# Tetrapod tracks from the Middle/Late Triassic of the Ourika and Yagour basins (Morocco): new ichnotaxonomical data based on the Biron collection

Jean-David Moreau, Naima Benaouiss, Abdelilah Tourani, Nour-Eddine Jalil, Sylvie Bourquin

► To cite this version:

Jean-David Moreau, Naima Benaouiss, Abdelilah Tourani, Nour-Eddine Jalil, Sylvie Bourquin. Tetrapod tracks from the Middle/Late Triassic of the Ourika and Yagour basins (Morocco): new ichnotaxonomical data based on the Biron collection. Journal of African Earth Sciences, 2024, 212, pp.105202. 10.1016/j.jafrearsci.2024.105202. insu-04452136

HAL Id: insu-04452136

https://insu.hal.science/insu-04452136

Submitted on 12 Feb 2024

HAL is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entific research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d'enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.

<figure><img src="image_1.png" /></figure>

Distributed under a Creative Commons Attribution 4.0 International License
# Tetrapod tracks from the Middle/Late Triassic of the Ourika and Yagour basins (Morocco): new ichnotaxonomical data based on the Biron collection

Jean-David Moreau, Naima Benaouiss, Abdelilah Tourani, Nour-Eddine Jalil, Sylvie Bourquin

<figure><img src="image_1.png" /></figure>

## ► To cite this version:

Jean-David Moreau, Naima Benaouiss, Abdelilah Tourani, Nour-Eddine Jalil, Sylvie Bourquin. Tetrapod tracks from the Middle/Late Triassic of the Ourika and Yagour basins (Morocco): new ichnotaxonomical data based on the Biron collection. Journal of African Earth Sciences, 2024, 212, pp.105202. 10.1016/j.jafrearsci.2024.105202. insu-04452136

HAL Id: insu-04452136

https://insu.hal.science/insu-04452136v1

Submitted on 12 Feb 2024

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

<figure><img src="image_2.png" /></figure>

Distributed under a Creative Commons Attribution 4.0 International License
Journal Pre-proof

Tetrapod tracks from the Middle/Late Triassic of the Ourika and Yagour basins
(Morocco): new ichnotaxonomical data based on the Biron collection

Jean-David Moreau, Naima Benaouiss, Abdelilah Tourani, Nour-Eddine Jalil, Sylvie Bourquin

PII: S1464-343X(24)00035-9

DOI: https://doi.org/10.1016/j.jafrearsci.2024.105202

Reference: AES 105202

To appear in: *Journal of African Earth Sciences*

Received Date: 9 October 2023

Revised Date: 9 February 2024

Accepted Date: 9 February 2024

<figure><img src="image_2.png" /></figure>

Please cite this article as: Moreau, J.-D., Benaouiss, N., Tourani, A., Jalil, N.-E., Bourquin, S., Tetrapod tracks from the Middle/Late Triassic of the Ourika and Yagour basins (Morocco): new ichnotaxonomical data based on the Biron collection, *Journal of African Earth Sciences* (2024), doi: https://doi.org/10.1016/j.jafrearsci.2024.105202.

This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

© 2024 Published by Elsevier Ltd.
Journal Pre-proof

Tetrapod tracks from the Middle/Late Triassic of the Ourika and Yagour basins
(Morocco): new ichnotaxonomical data based on the Biron collection

Jean-David Moreau, Naima Benaouiss, Abdelilah Tourani, Nour-Eddine Jalil, Sylvie Bourquin

PII: S1464-343X(24)00035-9

DOI: https://doi.org/10.1016/j.jafrearsci.2024.105202

Reference: AES 105202

To appear in: *Journal of African Earth Sciences*

Received Date: 9 October 2023

Revised Date: 9 February 2024

Accepted Date: 9 February 2024

Please cite this article as: Moreau, J.-D., Benaouiss, N., Tourani, A., Jalil, N.-E., Bourquin, S., Tetrapod tracks from the Middle/Late Triassic of the Ourika and Yagour basins (Morocco): new ichnotaxonomical data based on the Biron collection, *Journal of African Earth Sciences* (2024), doi: https://doi.org/10.1016/j.jafrearsci.2024.105202.

This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

© 2024 Published by Elsevier Ltd.

<figure><img src="image_3.png" /></figure>
1 **Tetrapod tracks from the Middle/Late Triassic of the Ourika and Yagour basins**

2 **(Morocco): new ichnotaxonomical data based on the Biron collection**

3 Jean-David Moreau a,*, Naima Benaouiss b, Abdelilah Tourani b, Nour-Eddine Jalil b,c, Sylvie

4 Bourquin d

5 a Biogéosciences, UMR CNRS 6282, Université de Bourgogne, 6 boulevard Gabriel, 21000,

6 Dijon, France.

7 b Département de géologie, Faculté des Sciences Semlalia, Université Cadi Ayyad, BP 2390,

8 Marrakech, 40000, Maroc.

9 c Centre de Recherches en Paléontologie-Paris (CR2P), UMR 7207,

10 CNRS/MNHN/SU/EPHE, Muséum national d'Histoire naturelle, Paris, France.

11 d Univ. Rennes, CNRS, Géosciences Rennes – UMR CNRS 6118, F-35000 Rennes, France.

12 *Corresponding author: jean.david.moreau@gmail.com

13

14 **Abstract:** Palaeontological prospecting organized in the Ourika and Yagour basins

15 (Marrakech High Atlas, Morocco) in the 1980's, have yielded abundant and exquisitely

16 preserved tetrapod tracks, some of them preserving thinly detailed skin traces (Collection

17 Biron, Cadi Ayyad, Marrakech, Morocco). Based on this material, diverse morphologies of

18 tracks were described and six new ichnotaxa were erected. However, these trackways have

19 never been reinvestigated in detail from an ichnotaxonomic point of view. Here, the Biron

20 collection is reevaluated using modern photogrammetric imaging techniques. The fine-
21 grained sandstone slabs bear trackways ascribed to *Apatopus lineatus*, *Isochirotherium* isp.

22 and *Rhynchosauroides* isp. whose trackmakers are possible phytosaurs, crocodylian-stem
23 archosaurs or non-crown-group archosauriforms and lepidosauromorphs/archosauromorphs,

24 respectively. “*Chirotherium atlensis*”, “*Enigmatopus atlensis*”, “*Hyloidichnus triasicus*”,

25 “*Prochirotherium triasicum*”, “*Pseudochirotherium oukaimedensis*” and “*Rectilinetopus*

26 *ourikensis*” are considered as invalid. The palaeoichnological assemblage includes a mixture
27 of Early to the Middle Triassic (*Isochirotherium*) and Late Triassic (*Apatopus lineatus*) tracks.

28 This result corroborates the biostratigraphic data recently obtain from the base of the

29 Oukaïmeden Sandstone Formation, suggesting a Middle-Late Triassic age. The living
30 environment was a semi-arid alluvial plain with ponds and ephemeral rivers.
1 **Tetrapod tracks from the Middle/Late Triassic of the Ourika and Yagour basins**

2 **(Morocco): new ichnotaxonomical data based on the Biron collection**

3 Jean-David Moreau a,*, Naima Benaouiss b, Abdelilah Tourani b, Nour-Eddine Jalil b,c, Sylvie

4 Bourquin d

5 a Biogéosciences, UMR CNRS 6282, Université de Bourgogne, 6 boulevard Gabriel, 21000,

6 Dijon, France.

7 b Département de géologie, Faculté des Sciences Semlalia, Université Cadi Ayyad, BP 2390,

8 Marrakech, 40000, Maroc.

9 c Centre de Recherches en Paléontologie-Paris (CR2P), UMR 7207,

10 CNRS/MNHN/SU/EPHE, Muséum national d'Histoire naturelle, Paris, France.

11 d Univ. Rennes, CNRS, Géosciences Rennes – UMR CNRS 6118, F-35000 Rennes, France.

12 *Corresponding author: jean.david.moreau@gmail.com

13

14 **Abstract:** Palaeontological prospecting organized in the Ourika and Yagour basins

15 (Marrakech High Atlas, Morocco) in the 1980's, have yielded abundant and exquisitely

16 preserved tetrapod tracks, some of them preserving thinly detailed skin traces (Collection

17 Biron, Cadi Ayyad, Marrakech, Morocco). Based on this material, diverse morphologies of

18 tracks were described and six new ichnotaxa were erected. However, these trackways have

19 never been reinvestigated in detail from an ichnotaxonomic point of view. Here, the Biron

20 collection is reevaluated using modern photogrammetric imaging techniques. The fine-
21 grained sandstone slabs bear trackways ascribed to *Apatopus lineatus*, *Isochirotherium* isp.

22 and *Rhynchosauroides* isp. whose trackmakers are possible phytosaurs, crocodylian-stem
23 archosaurs or non-crown-group archosauriforms and lepidosauromorphs/archosauromorphs,
24 respectively. "*Chirotherium atlensis*", "*Enigmatopus atlensis*", "*Hyloidichnus triasicus*",

25 "*Prochirotherium triasicum*", "*Pseudochirotherium oukaimedensis*" and "*Rectilinetopus*

26 *ourikensis*" are considered as invalid. The palaeoichnological assemblage includes a mixture
27 of Early to the Middle Triassic (*Isochirotherium*) and Late Triassic (*Apatopus lineatus*) tracks.

28 This result corroborates the biostratigraphic data recently obtain from the base of the

29 Oukaïmeden Sandstone Formation, suggesting a Middle-Late Triassic age. The living
30 environment was a semi-arid alluvial plain with ponds and ephemeral rivers.
31 **Keywords**: tetrapod tracks; Mesozoic; Ladinian; Carnian; Marrakech High Atlas;
32 photogrammetry

33

34 **1. Introduction**

35 In Morocco, significant ichnofossils including abundant and diverse vertebrate and
36 invertebrate tracks were reported from Triassic deposits of the Argana Basin (Klein et al.,
37 2010, 2011; Tourani et al., 2010; Lagnaoui et al., 2012, 2016; Zouheir et al., 2020), the Sidi
38 Saïd Maachou Basin (Hminna et al., 2013, 2020, 2021) and the Yagour Plateau (Biron and
39 Dutuit, 1981; Biron, 1982). They constitute a key for the reconstruction of continental early
40 Mesozoic palaeoecosystems (Biron and Dutuit, 1981; Klein et al., 2010, 2011; Tourani et al.,
41 2010; Lagnaoui et al., 2012, 2016; Zouheir et al., 2020; Hminna et al., 2013, 2020, 2021).
42 Whereas tracks from the Triassic deposits of the Argana Basin were abundantly studied
43 (Biron and Dutuit, 1981; Klein et al., 2010, 2011; Tourani et al., 2010; Lagnaoui et al., 2012,
44 2016; Zouheir et al., 2020), those from the Ourika and Yagour basins clearly appear to be
45 underestimated. In 1981, Pierre-Eymard Biron discovered several tracksites (Biron and
46 Dutuit, 1981; Biron, 1982). This material was described by Biron and Dutuit (1981) who
47 dated it as Late Triassic. In this study, they described two slabs bearing exquisitely preserved
48 tracks that they attributed to *Apatopus lineatus* and a new species of *Chirotherium*: "*C.
atlensis*".
49 Then, based on isolated pes or manus tracks, they briefly described five additional
50 new ichnotaxa: "*Enigmatopus atlensis*", "*Hyloidichnus triasicus*", "*Prochirotherium
51 triasicum*", "*Pseudochirotherium oukaimedensis*" and "*Rectilinetopus ourikensis*". Except for
52 a tentative discussion by Klein and Lucas (2013, 2021) of some of these ichnospecies, the
53 tracks from the Ourika and Yagour basins have never been reinvestigated in detail. Here, we
54 revised Biron's material housed at the Cadi Ayyad University (Marrakech). We describe it
55 using photogrammetric imaging techniques, update the ichnotaxonomy of the tracks and
56 discuss their age.

57

58 **2. Geographical and geological setting**

59
31 **Keywords**: tetrapod tracks; Mesozoic; Ladinian; Carnian; Marrakech High Atlas;
32 photogrammetry

33

34 **1. Introduction**

35 In Morocco, significant ichnofossils including abundant and diverse vertebrate and
36 invertebrate tracks were reported from Triassic deposits of the Argana Basin (Klein et al.,
37 2010, 2011; Tourani et al., 2010; Lagnaoui et al., 2012, 2016; Zouheir et al., 2020), the Sidi
38 Saïd Maachou Basin (Hminna et al., 2013, 2020, 2021) and the Yagour Plateau (Biron and
39 Dutuit, 1981; Biron, 1982). They constitute a key for the reconstruction of continental early
40 Mesozoic palaeoecosystems (Biron and Dutuit, 1981; Klein et al., 2010, 2011; Tourani et al.,
41 2010; Lagnaoui et al., 2012, 2016; Zouheir et al., 2020; Hminna et al., 2013, 2020, 2021).
42 Whereas tracks from the Triassic deposits of the Argana Basin were abundantly studied
43 (Biron and Dutuit, 1981; Klein et al., 2010, 2011; Tourani et al., 2010; Lagnaoui et al., 2012,
44 2016; Zouheir et al., 2020), those from the Ourika and Yagour basins clearly appear to be
45 underestimated. In 1981, Pierre-Eymard Biron discovered several tracksites (Biron and
46 Dutuit, 1981; Biron, 1982). This material was described by Biron and Dutuit (1981) who
47 dated it as Late Triassic. In this study, they described two slabs bearing exquisitely preserved
48 tracks that they attributed to *Apatopus lineatus* and a new species of *Chirotherium*: "*C.
atlensis*".
49 Then, based on isolated pes or manus tracks, they briefly described five additional
50 new ichnotaxa: "*Enigmatopus atlensis*", "*Hyloidichnus triasicus*", "*Prochirotherium
51 triasicum*", "*Pseudochirotherium oukaimedensis*" and "*Rectilinetopus ourikensis*". Except for
52 a tentative discussion by Klein and Lucas (2013, 2021) of some of these ichnospecies, the
53 tracks from the Ourika and Yagour basins have never been reinvestigated in detail. Here, we
54 revised Biron's material housed at the Cadi Ayyad University (Marrakech). We describe it
55 using photogrammetric imaging techniques, update the ichnotaxonomy of the tracks and
56 discuss their age.

57

58 **2. Geographical and geological setting**

59
The study area is located in the Marrakech High Atlas (Fig. 1A), 60 to 80 km southeast of Marrakech. At the south of the Carboniferous Ourika-Zat anticline (Fig. 1B), the Permian and Triassic outcrops overlie the deformed Variscan basement, represented by Precambrian volcanic rocks, Cambrian series, granitoids and metamorphic rocks, or Carboniferous deposits. The Permian and Triassic rift area is related to the NW-SE-oriented extension, which generated N-S trending normal faults (Van Houten, 1977; El Arabi et al., 2003; Qarbous et al., 2003; Baudon et al., 2009) and reactivated pre-existing NE-SW to ENE-WSW Variscan structures (Fig. 1B). These dip-slip and strike-slip faults are reactivated (Baudon et al., 2009; El Arabi, 1988; El Arabi et al., 2003; Laville and Petit, 1984; Laville and Piqué, 1991) and controlled the Triassic sedimentation (Benaouiss et al., 2023). The Permian and Triassic sedimentary successions are represented by elongated and narrow tectonic belts with an ENE-WSW orientation (Fig. 1B), up to 17 km wide and up to 35 km long. These Permian and Triassic deposits are subdivided into six formations (fms), noted F1 to F6 (Biron, 1982; Fig. 1C), corresponding to the Permian Anrar Conglomerate (F1), dated by radioactive and zircon method (Van Houten, 1977 and Perez et al., 2019) and the Cham-El-Houa Siltstone (F2), located below the Permian-Triassic unconformity, is attributed to the Permian age by correlation with the Argana t2 Unit (e.g. Benaouiss et al., 2023). The F3 (Timalizène Conglomerate), F4 (Anouffig Siltstone), F5 (Oukaïmeden Sandstone), and F6 (Tafilalt Siltstone) fms of Biron (1982) correspond respectively to the Basal Conglomerate, Ramuntcho Siltstone, the Oukaïmeden Sandstone and Upper Siltstone fms of Mattis (1977). The F3 Formation (Fm) is attributed to Early Triassic (e.g. Benaouiss et al., 2023) by correlation with the t3 Unit in the Argana Basin, dated by Tourani et al. (2010) with tetrapod tracks. Based on pollen analyses, the lower part of F4 Fm is middle Anisian age (El Arabi et al., 2006) and the F5 Fm is dated middle Carnian at its lower (Biron and Courtinat, 1982) and upper parts (Cousminer and Manspeizer, 1976) (Fig. 1C). The base of the Oukaïmeden Sandstone Fm was recently dated by pollen grains and conchostracans as Ladinian-early Carnian (Benaouiss et al., 2018). This part of F5 Fm represents the equivalent of the lower part of the t5 Unit in the Argana Basin which is dated as Julian-Tuvalian (mid-Carnian) by Tourani et al. (2023). The F6 Fm is attributed to the Norian, by correlation to the t8 Unit in the Argana Basin which is dated by conchostracans according to Weems and Lucas (2015). The Triassic series is overlain by Early Jurassic basalts, representing a good stratigraphic marker across Morocco (Bertrand et al., 1982; Blackburn et al., 2013; De Pachtère, 1983; Marzoli et al., 2004).
The study area is located in the Marrakech High Atlas (Fig. 1A), 60 to 80 km southeast of Marrakech. At the south of the Carboniferous Ourika-Zat anticline (Fig. 1B), the Permian and Triassic outcrops overlie the deformed Variscan basement, represented by Precambrian volcanic rocks, Cambrian series, granitoids and metamorphic rocks, or Carboniferous deposits. The Permian and Triassic rift area is related to the NW-SE-oriented extension, which generated N-S trending normal faults (Van Houten, 1977; El Arabi et al., 2003; Qarbous et al., 2003; Baudon et al., 2009) and reactivated pre-existing NE-SW to ENE-WSW Variscan structures (Fig. 1B). These dip-slip and strike-slip faults are reactivated (Baudon et al., 2009; El Arabi, 1988; El Arabi et al., 2003; Laville and Petit, 1984; Laville and Piqué, 1991) and controlled the Triassic sedimentation (Benaouiss et al., 2023). The Permian and Triassic sedimentary successions are represented by elongated and narrow tectonic belts with an ENE-WSW orientation (Fig. 1B), up to 17 km wide and up to 35 km long. These Permian and Triassic deposits are subdivided into six formations (fms), noted F1 to F6 (Biron, 1982; Fig. 1C), corresponding to the Permian Anrar Conglomerate (F1), dated by radioactive and zircon method (Van Houten, 1977 and Perez et al., 2019) and the Cham-El-Houa Siltstone (F2), located below the Permian-Triassic unconformity, is attributed to the Permian age by correlation with the Argana t2 Unit (e.g. Benaouiss et al., 2023). The F3 (Timalizène Conglomerate), F4 (Anouffig Siltstone), F5 (Oukaïmeden Sandstone), and F6 (Tafilalt Siltstone) fms of Biron (1982) correspond respectively to the Basal Conglomerate, Ramuntcho Siltstone, the Oukaïmeden Sandstone and Upper Siltstone fms of Mattis (1977). The F3 Formation (Fm) is attributed to Early Triassic (e.g. Benaouiss et al., 2023) by correlation with the t3 Unit in the Argana Basin, dated by Tourani et al. (2010) with tetrapod tracks. Based on pollen analyses, the lower part of F4 Fm is middle Anisian age (El Arabi et al., 2006) and the F5 Fm is dated middle Carnian at its lower (Biron and Courtinat, 1982) and upper parts (Cousminer and Manspeizer, 1976) (Fig. 1C). The base of the Oukaïmeden Sandstone Fm was recently dated by pollen grains and conchostracans as Ladinian-early Carnian (Benaouiss et al., 2018). This part of F5 Fm represents the equivalent of the lower part of the t5 Unit in the Argana Basin which is dated as Julian-Tuvalian (mid-Carnian) by Tourani et al. (2023). The F6 Fm is attributed to the Norian, by correlation to the t8 Unit in the Argana Basin which is dated by conchostracans according to Weems and Lucas (2015). The Triassic series is overlain by Early Jurassic basalts, representing a good stratigraphic marker across Morocco (Bertrand et al., 1982; Blackburn et al., 2013; De Pachtère, 1983; Marzoli et al., 2004).
Two main Triassic outcrops are of interest to this study (Fig. 1B): (1) those of the Ourika Basin, which is limited at the north by the Sidi Ali-Ou-Fars fault and at the south by the Oukaïmeden fault (Fig. 1B), (2) those of the Yagour Basin, which is limited by the Sidi Ali-Ou-Fars and Tafrawt faults at the north and the Meltsene fault at the south (Fig. 1B).

Biron and Dutuit (1981) reported three tracksites on the Ourika and Yagour basins, at the East of Aghbalou, at the North-East of Anammer and at the North-West of the Yagour Plateau (Star symbol in Fig. 1B). The historical tracksites are located at the base of the Oukaïmeden Sandstone Fm (Fig. 1B and C). This formation is up to 600 m thick and outcrops mainly as cliffs, accessible along streams and tracks, and is mainly characterized by channel sandstone bodies alternating with lenticular fluvial bar sandstones and overbank mudstone deposits (Benaouiss et al., 1996; Fabuel-Perez et al., 2009). The Oukaïmeden Sandstone Fm is subdivided into three units (Benaouiss et al., 1996; Fabuel-Perez et al., 2009), called lower-, middle- and upper Okaïmeden units. The lower unit, which yields the fossil tracks, is 30 to 110 m thick. It is richer, than the middle and upper units, in red clay-stones and siltstones, and was deposited in an ephemeral fluvial system under dry climate. The middle unit is 25 to 80 m thick, and corresponds to a distal braided system associated with more humid conditions (Fabuel-Perez et al., 2009). The upper unit, which is 30 to 80 m thick, corresponds to the comeback of ephemeral conditions with the installation of aeolian dunes corresponding to arid conditions (Benaouiss et al., 1996; Fabuel-Perez et al., 2009).

## 3. Material and methods

The palaeontological collection of the department of Geology (Cadi Ayyad University) includes two large fine-grained sandstone slabs bearing tetrapod tracks, described and figured in Biron and Dutuit (1981) (Figs. 2 and 3). These slabs called “Dalle 1” and “Dalle 2” in Biron and Dutuit (1981), bear currently the collection numbers UCA.82 and UCA.83, respectively. The slab UCA.82 (Fig. 2), was collected at the base of the Yagour Plateau whereas the geographical origin of the slab UCA.83 (Fig. 3) was not indicated in Biron and Dutuit (1981). The slab UCA.82 (63 cm long and 58 cm wide) bears eight large and exquisitely preserved tracks briefly described by Biron and Dutuit (1981) for which they erected the new ichnospecies “Chirotherium atlensis”. The slab UCA.82 also bears numerous (around one hundred) small lacertoid tracks (Rhynchosauroides) undescribed by Biron and
Two main Triassic outcrops are of interest to this study (Fig. 1B): (1) those of the Ourika Basin, which is limited at the north by the Sidi Ali-Ou-Fars fault and at the south by the Oukaïmeden fault (Fig. 1B), (2) those of the Yagour Basin, which is limited by the Sidi Ali-Ou-Fars and Tafrawt faults at the north and the Meltsene fault at the south (Fig. 1B).

Biron and Dutuit (1981) reported three tracksites on the Ourika and Yagour basins, at the East of Aghbalou, at the North-East of Anammer and at the North-West of the Yagour Plateau (Star symbol in Fig. 1B). The historical tracksites are located at the base of the Oukaïmeden Sandstone Fm (Fig. 1B and C). This formation is up to 600 m thick and outcrops mainly as cliffs, accessible along streams and tracks, and is mainly characterized by channel sandstone bodies alternating with lenticular fluvial bar sandstones and overbank mudstone deposits (Benaouiss et al., 1996; Fabuel-Perez et al., 2009). The Oukaïmeden Sandstone Fm is subdivided into three units (Benaouiss et al., 1996; Fabuel-Perez et al., 2009), called lower-, middle- and upper Okaïmeden units. The lower unit, which yields the fossil tracks, is 30 to 110 m thick. It is richer, than the middle and upper units, in red clay-stones and siltstones, and was deposited in an ephemeral fluvial system under dry climate. The middle unit is 25 to 80 m thick, and corresponds to a distal braided system associated with more humid conditions (Fabuel-Perez et al., 2009). The upper unit, which is 30 to 80 m thick, corresponds to the comeback of ephemeral conditions with the installation of aeolian dunes corresponding to arid conditions (Benaouiss et al., 1996; Fabuel-Perez et al., 2009).

## 3. Material and methods

The palaeontological collection of the department of Geology (Cadi Ayyad University) includes two large fine-grained sandstone slabs bearing tetrapod tracks, described and figured in Biron and Dutuit (1981) (Figs. 2 and 3). These slabs called “Dalle 1” and “Dalle 2” in Biron and Dutuit (1981), bear currently the collection numbers UCA.82 and UCA.83, respectively. The slab UCA.82 (Fig. 2), was collected at the base of the Yagour Plateau whereas the geographical origin of the slab UCA.83 (Fig. 3) was not indicated in Biron and Dutuit (1981). The slab UCA.82 (63 cm long and 58 cm wide) bears eight large and exquisitely preserved tracks briefly described by Biron and Dutuit (1981) for which they erected the new ichnospecies “Chirotherium atlensis”. The slab UCA.82 also bears numerous (around one hundred) small lacertoid tracks (Rhynchosauroides) undescribed by Biron and
Dutuit (1981) but briefly mentioned in Biron (1982). The slab UCA.83 (44 cm long and 41 cm wide) bears eight large tracks briefly described by Biron and Dutuit (1981) who ascribed them to *Apatopus lineatus* (Fig. 3). This slab also bears four isolated and partial small lacertoid tracks ascribed to *Rhynchosauroides* (Fig. 4). On both slabs, tetrapod ichnofossils are preserved as convex hyporeliefs. The tracks that Biron and Dutuit (1981) described as "*Enigmatopus atlensis*", "*Hyloidichnus triasicus*", "*Prochirotherium triasicum*", and "*Rectilinetopus ourikensis*" (Fig. 5) were preserved on large isolated blocs left in place on the field (unfortunately not precisely located in Biron and Dutuit, 1981).

The descriptive terminology and biometric parameters used in this study follow those of Haubold (1971) and Leonardi (1987). We used the following standard abbreviations: ML, manus track length; MW, manus track width; ML/MW, length to width ratio of manus track; PL., pes track length; PW, pes track width; and PL/PW, length to width ratio of pes track.

3D photogrammetric reconstructions were produced with the software Agisoft Metashape Professional 2.0. Pictures of the surfaces were taken with a Nikon D5200 camera coupled with an AF-S Nikkor 18-105 128 mm f/3.5-5.6G ED lens. The same software was used to produce photogrammetric digital elevation models and contours.

141

## 4. Systematic palaeoichnology

143

### Isochirotherium isp.

Fig. 2A–F

*Material.* Eight tracks preserved as convex hyporeliefs on slab UCA.82, Cadi Ayyad University (Marrakech).

*Description.* The slab UCA.82 bears eight semi-plantigrade and quadrupedal tracks, including five pes tracks and three manus imprints (including three pes/manus sets; Fig. 2A–C). Two pes/manus sets are part of a trackway (Fig. 2A–C). Pes and manus tracks from the same set form a small divergent angle of 12 to 15°. Pes and manus track paces are 34.5 cm and 36.0 cm long, respectively. The pes and manus tracks are strongly oriented outward.

Pes imprints are pentadactyl, longer than wide, 16–17 cm long and 10.7–11.8 cm wide (Fig. 2D–F). The PL/PW ratio varies from 1.4 to 1.5. Digit imprints I-V are elongated, robust,
Dutuit (1981) but briefly mentioned in Biron (1982). The slab UCA.83 (44 cm long and 41 cm wide) bears eight large tracks briefly described by Biron and Dutuit (1981) who ascribed them to *Apatopus lineatus* (Fig. 3). This slab also bears four isolated and partial small lacertoid tracks ascribed to *Rhynchosauroides* (Fig. 4). On both slabs, tetrapod ichnofossils are preserved as convex hyporeliefs. The tracks that Biron and Dutuit (1981) described as "*Enigmatopus atlensis*", "*Hyloidichnus triasicus*", "*Prochirotherium triasicum*", and "*Rectilinetopus ourikensis*" (Fig. 5) were preserved on large isolated blocs left in place on the field (unfortunately not precisely located in Biron and Dutuit, 1981).

The descriptive terminology and biometric parameters used in this study follow those of Haubold (1971) and Leonardi (1987). We used the following standard abbreviations: ML, manus track length; MW, manus track width; ML/MW, length to width ratio of manus track; PL., pes track length; PW, pes track width; and PL/PW, length to width ratio of pes track.

3D photogrammetric reconstructions were produced with the software Agisoft Metashape Professional 2.0. Pictures of the surfaces were taken with a Nikon D5200 camera coupled with an AF-S Nikkor 18-105 128 mm f/3.5-5.6G ED lens. The same software was used to produce photogrammetric digital elevation models and contours.

141

## 4. Systematic palaeoichnology

143

### Isochirotherium isp.

Fig. 2A–F

*Material.* Eight tracks preserved as convex hyporeliefs on slab UCA.82, Cadi Ayyad University (Marrakech).

*Description.* The slab UCA.82 bears eight semi-plantigrade and quadrupedal tracks, including five pes tracks and three manus imprints (including three pes/manus sets; Fig. 2A–C). Two pes/manus sets are part of a trackway (Fig. 2A–C). Pes and manus tracks from the same set form a small divergent angle of 12 to 15°. Pes and manus track paces are 34.5 cm and 36.0 cm long, respectively. The pes and manus tracks are strongly oriented outward.

Pes imprints are pentadactyl, longer than wide, 16–17 cm long and 10.7–11.8 cm wide (Fig. 2D–F). The PL/PW ratio varies from 1.4 to 1.5. Digit imprints I-V are elongated, robust,
straight and apically pointed. They form a group oriented outward, whereas imprint of digit V
is curved rearward. The position of the impression of digit V is more proximal than those of
digits I-IV. Traces of digit V show a well-imprinted, oval and longer than wide proximal pad
that is in line with impression of digit IV (Fig. 2D–F). The impressions of the digit II and III
(that are similar in length) are the longest. The impressions of digits I and IV are shorter than
those of II and III. The divarication angle of digits I-IV and digits I-V varies from 20 to 35°
and 52 to 54°, respectively.

Manus imprints are pentadactyl, quite symmetrical, smaller than pes tracks (PL/ML=
2.6), wider than long (ML=6.5 cm, MW=7.3 cm, ML/MW ratio = 0.9; Fig. 2D–F). The digit
imprints are moderately elongated, straight and apically pointed. The impression of the digit
III is the longest. The impression of digit V is shallower than others. The impression of the
digit I is the shortest. The divarication angle of digits I-V is up to 120°. Proximal pads of
digits I–V form a posteriorly concave margin. Manus tracks sometimes show a poorly marked
sole. On pes and manus tracks, phalangeal nodes, skin detailed-structures and large triangular
claws are very well-preserved (Fig. 2D–F). The slab UCA.82 bears thin, elongated and
straight to curved ridges that could be possible tail marks (Fig. 2C).

**Remarks.** Biron and Dutuit (1981) identified these tracks as a new species, they named "Chirotherium atlensis". The gross morphologies of *Chirotherium* and *Isochirotherium* are very similar. However, *Isochirotherium* differs from *Chirotherium* by the size of pedal digits II and III that are quite similar in length (Klein et al., 2011, 2013). In *Chirotherium* the digit III is the longest. For this reason, we attribute the tracks from the slab UCA.82 to *Isochirotherium* and consider the ichnospecies "*Chirotherium atlensis*" as an invalid name. Chirotherian tracks (*Brachychirotherium*, *Parachirotherium*, *Protochirotherium*, and *Synaptichnium*), were abundantly described from the Triassic of Morocco: in the Sidi Saïd Maachou (Hminna et al., 2013, 2021) and Argana basins (Klein et al., 2010, 2011; Tourani et al., 2010; Lagnaoui et al., 2012, 2016; Zouheir et al., 2020). They all differ from the tracks of the slab UCA.82: *Brachychirotherium* (Fig. 6A) differs by broad pes that has short and broad digits and the oval basal pad of digit V that is in a postero-lateral position relatively to the anterior digit group I–IV; *Parachirotherium* (Fig. 6C) differs by the pentadactyl, functionally tridactyl pes traks with a wide divarication angle I-V, reduced imprints of digits II and IV, and a posteriorly shifted digit I. Lagnaoui et al. (2012, 2016) mentioned the occurrence of *Parachirotherium* in the Late Triassic of the Argana Basin. Nevertheless, according to Klein and Lucas (2021) *Parachirotherium* should be regarded as a junior synonym of *Chirotherium*;
straight and apically pointed. They form a group oriented outward, whereas imprint of digit V
is curved rearward. The position of the impression of digit V is more proximal than those of
digits I-IV. Traces of digit V show a well-imprinted, oval and longer than wide proximal pad
that is in line with impression of digit IV (Fig. 2D–F). The impressions of the digit II and III
(that are similar in length) are the longest. The impressions of digits I and IV are shorter than
those of II and III. The divarication angle of digits I-IV and digits I-V varies from 20 to 35°
and 52 to 54°, respectively.

Manus imprints are pentadactyl, quite symmetrical, smaller than pes tracks (PL/ML=
2.6), wider than long (ML=6.5 cm, MW=7.3 cm, ML/MW ratio = 0.9; Fig. 2D–F). The digit
imprints are moderately elongated, straight and apically pointed. The impression of the digit
III is the longest. The impression of digit V is shallower than others. The impression of the
digit I is the shortest. The divarication angle of digits I-V is up to 120°. Proximal pads of
digits I–V form a posteriorly concave margin. Manus tracks sometimes show a poorly marked
sole. On pes and manus tracks, phalangeal nodes, skin detailed-structures and large triangular
claws are very well-preserved (Fig. 2D–F). The slab UCA.82 bears thin, elongated and
straight to curved ridges that could be possible tail marks (Fig. 2C).

**Remarks.** Biron and Dutuit (1981) identified these tracks as a new species, they named "Chirotherium atlensis". The gross morphologies of *Chirotherium* and *Isochirotherium* are very similar. However, *Isochirotherium* differs from *Chirotherium* by the size of pedal digits II and III that are quite similar in length (Klein et al., 2011, 2013). In *Chirotherium* the digit III is the longest. For this reason, we attribute the tracks from the slab UCA.82 to *Isochirotherium* and consider the ichnospecies "*Chirotherium atlensis*" as an invalid name. Chirotherian tracks (*Brachychirotherium*, *Parachirotherium*, *Protochirotherium*, and *Synaptichnium*), were abundantly described from the Triassic of Morocco: in the Sidi Saïd Maachou (Hminna et al., 2013, 2021) and Argana basins (Klein et al., 2010, 2011; Tourani et al., 2010; Lagnaoui et al., 2012, 2016; Zouheir et al., 2020). They all differ from the tracks of the slab UCA.82: *Brachychirotherium* (Fig. 6A) differs by broad pes that has short and broad digits and the oval basal pad of digit V that is in a postero-lateral position relatively to the anterior digit group I–IV; *Parachirotherium* (Fig. 6C) differs by the pentadactyl, functionally tridactyl pes traks with a wide divarication angle I-V, reduced imprints of digits II and IV, and a posteriorly shifted digit I. Lagnaoui et al. (2012, 2016) mentioned the occurrence of *Parachirotherium* in the Late Triassic of the Argana Basin. Nevertheless, according to Klein and Lucas (2021) *Parachirotherium* should be regarded as a junior synonym of *Chirotherium*;
Protochirotherium (emended in Klein and Lucas, 2021 after Fichter and Kunz, 2004) differs from the tracks of the slab UCA.82 by larger manus tracks compared to the size of pes track and digit V of pes with strongly elongated pad proximally (Fig. 6D); Synaptichnium differs by a more slender overall shape, a less massive pedal digit V, and a pedal digit IV that is subequal with or even longer than digit III (Fig. 6E). In Morocco, Tourani et al. (2010) and Klein et al., (2011) reported Isochirotherium cf. gierlinskii and Isochirotherium courelifrom the Triassic of the Argana Basin. The tracks described as Isochirotherium cf. gierlinskii in Tourani et al. (2010) were tentatively renamed Protochirotherium by Klein et al. (2013). The tracks of the slab UCA.82 has no distinctive character supporting the creation of a new species nor can it be confidently assigned to any of the known species of Isochirotherium.

According to Klein and Lucas (2021), the valid Isochirotherium ichnospecies are I. coltoni, I. coureli, I. delicatum, I. herculis, I. lomasi, I. marshalli and I. soergeli. I. coureli differs from the tracks of the slab UCA.82 in showing higher PL/PW ratio (up to 1.9). I. soergeli differs in showing pes tracks with as long as wide to slightly longer than wide group I-IV. I. delicatum shows more elongated pes tracks with long traces of digits II-III as well as very short traces of digits I and IV. I. marshalli differs from the tracks of the slab UCA.82 in showing a bigger ovoid metatarsal-phalangeal pad on the digit V of pes tracks. I. herculis shows strongly bigger pes (PL can be more than 30 cm) and a group I-IV which is wider than long. I. coltoni and I. soergeli are clearly smaller than the tracks of the slab UCA.82. Similar to the tracks we describe here, the pes track of I. lomasi shows a longer than wide group I-IV. However, I. lomasi displays a higher PL/PW ratio (more than 1.6) and a shorter trace of digit IV on pes track.

210

211 *Apatopus lineatus* Bock, 1952

212 Fig. 3A–G

213

214 *Material.* Eight tracks preserved as convex hyporeliefs on slab UCA.83, Cadi Ayyad University (Marrakech).

216 *Description.* The slab UCA.83 bears eight plantigrade to semi-plantigrade and quadrupedal tracks, with four pes tracks and three manus imprints (including three pes/manus sets; Fig. 3A–C). Two pes/manus sets are part of a trackway (Fig. 3C). Pes and manus tracks from the
Protochirotherium (emended in Klein and Lucas, 2021 after Fichter and Kunz, 2004) differs from the tracks of the slab UCA.82 by larger manus tracks compared to the size of pes track and digit V of pes with strongly elongated pad proximally (Fig. 6D); Synaptichnium differs by a more slender overall shape, a less massive pedal digit V, and a pedal digit IV that is subequal with or even longer than digit III (Fig. 6E). In Morocco, Tourani et al. (2010) and Klein et al., (2011) reported Isochirotherium cf. gierlinskii and Isochirotherium courelifrom the Triassic of the Argana Basin. The tracks described as Isochirotherium cf. gierlinskii in Tourani et al. (2010) were tentatively renamed Protochirotherium by Klein et al. (2013). The tracks of the slab UCA.82 has no distinctive character supporting the creation of a new species nor can it be confidently assigned to any of the known species of Isochirotherium.

According to Klein and Lucas (2021), the valid Isochirotherium ichnospecies are *I. coltoni*, *I. coureli*, *I. delicatum*, *I. herculis*, *I. lomasi*, *I. marshalli* and *I. soergeli*. *I. coureli* differs from the tracks of the slab UCA.82 in showing higher PL/PW ratio (up to 1.9). *I. soergeli* differs in showing pes tracks with as long as wide to slightly longer than wide group I-IV. *I. delicatum* shows more elongated pes tracks with long traces of digits II-III as well as very short traces of digits I and IV. *I. marshalli* differs from the tracks of the slab UCA.82 in showing a bigger ovoid metatarsal-phalangeal pad on the digit V of pes tracks. *I. herculis* shows strongly bigger pes (PL can be more than 30 cm) and a group I-IV which is wider than long. *I. coltoni* and *I. soergeli* are clearly smaller than the tracks of the slab UCA.82. Similar to the tracks we describe here, the pes track of *I. lomasi* shows a longer than wide group I-IV. However, *I. lomasi* displays a higher PL/PW ratio (more than 1.6) and a shorter trace of digit IV on pes track.

210

211 *Apatopus lineatus* Bock, 1952

212 Fig. 3A–G

213

214 *Material*. Eight tracks preserved as convex hyporeliefs on slab UCA.83, Cadi Ayyad University (Marrakech).

216 *Description*. The slab UCA.83 bears eight plantigrade to semi-plantigrade and quadrupedal tracks, with four pes tracks and three manus imprints (including three pes/manus sets; Fig. 3A–C). Two pes/manus sets are part of a trackway (Fig. 3C). Pes and manus tracks from the
219

220

221

same set form divergent angle of 22 to 40°. Pes and manus track paces are 22.5 cm and 19.0 cm long, respectively. The pes tracks are oriented outward whereas manus tracks are oriented forward to inward.

222

223

224

225

226

227

Pes imprints are pentadactyl, longer than wide, 10.0–10.5 cm long and 4.7–6.0 cm wide (Fig. 3D–G). The PL/PW ratio varies from 1.7 to 2.1. Digit imprints are elongated, straight and apically pointed. The impressions of digit increase in length from I to IV. The impression of digit V is shallower than others, nearly absent. Digits I-IV shows a sub-parallel arrangement. The divarication angle of digits I-V varies from 40 to 41°. Pes tracks show a large and triangular plantar-like impression (Fig. 3D–G).

228

229

230

231

232

233

234

Manus imprints are pentadactyl, smaller than pes tracks, longer than wide to as long as wide (ML=5.1–6.0 cm, MW=4.4–5.2 cm; Fig. 3D–G). The ML/MW ratio varies from 0.8 to 1.2. Digit imprints are short, straight and apically pointed. The impression of the digit III is the longest. The divarication angle of digits I-V varies from 68 to 70°. Manus tracks sometimes show a poorly impressed sole. Marks of phalangeal nodes and claws are very well-preserved on both pes and manus tracks (Fig. 3D–G).

235

236

237

238

239

240

241

242

243

244

245

246

247

248

249

250

251

**Remarks.** Based on the following characters, these tracks match with the diagnostic features of *Apatopus lineatus*: quadrupedal trackways; pes long and narrow, plantigrade, pentadactyl with slender digits increasing in length from I to IV; digits with well-developed articular swellings and sharp claw impressions; manus pentadactyl, semi-plantigrade, short, and quite symmetrical around digit III, which is the longest. Biron and Dutuit (1981) correctly ascribed these tracks to *Apatopus lineatus*. However they committed several mistakes in their interpretations of the tracks: (1) their interpretative sketch of the trackway (Biron and Dutuit, 1981; fig. 9B p. 412) is not concordant with what can be seen on the slab - although Biron and Dutuit (1981) noted a problem of laterally of right/left sets, it appears that they erroneously associated two manus/pes sets to a same trackway - this misinterpretation explained why the order of digits I-V is inverted on their stretch (Biron and Dutuit, 1981; fig. 9B p. 412; digit I towards the outside of the trackway whereas digit V was located towards the inside); (2) although they mentioned five digits on manus tracks, they drawed only up to four digits on their interpretative sketch (Biron and Dutuit, 1981; fig. 9 p. 412) of the trackway. The gross morphologies of *Apatopus* and *Synaptichnium* show many similarities. However,
219

220

221

same set form divergent angle of 22 to 40°. Pes and manus track paces are 22.5 cm and 19.0 cm long, respectively. The pes tracks are oriented outward whereas manus tracks are oriented forward to inward.

222

223

224

225

226

227

Pes imprints are pentadactyl, longer than wide, 10.0–10.5 cm long and 4.7–6.0 cm wide (Fig. 3D–G). The PL/PW ratio varies from 1.7 to 2.1. Digit imprints are elongated, straight and apically pointed. The impressions of digit increase in length from I to IV. The impression of digit V is shallower than others, nearly absent. Digits I-IV shows a sub-parallel arrangement. The divarication angle of digits I-V varies from 40 to 41°. Pes tracks show a large and triangular plantar-like impression (Fig. 3D–G).

228

229

230

231

232

233

234

Manus imprints are pentadactyl, smaller than pes tracks, longer than wide to as long as wide (ML=5.1–6.0 cm, MW=4.4–5.2 cm; Fig. 3D–G). The ML/MW ratio varies from 0.8 to 1.2. Digit imprints are short, straight and apically pointed. The impression of the digit III is the longest. The divarication angle of digits I-V varies from 68 to 70°. Manus tracks sometimes show a poorly impressed sole. Marks of phalangeal nodes and claws are very well-preserved on both pes and manus tracks (Fig. 3D–G).

235

236

237

238

239

240

241

242

243

244

245

246

247

248

249

250

251

**Remarks.** Based on the following characters, these tracks match with the diagnostic features of *Apatopus lineatus*: quadrupedal trackways; pes long and narrow, plantigrade, pentadactyl with slender digits increasing in length from I to IV; digits with well-developed articular swellings and sharp claw impressions; manus pentadactyl, semi-plantigrade, short, and quite symmetrical around digit III, which is the longest. Biron and Dutuit (1981) correctly ascribed these tracks to *Apatopus lineatus*. However they committed several mistakes in their interpretations of the tracks: (1) their interpretative sketch of the trackway (Biron and Dutuit, 1981; fig. 9B p. 412) is not concordant with what can be seen on the slab - although Biron and Dutuit (1981) noted a problem of laterally of right/left sets, it appears that they erroneously associated two manus/pes sets to a same trackway - this misinterpretation explained why the order of digits I-V is inverted on their stretch (Biron and Dutuit, 1981; fig. 9B p. 412; digit I towards the outside of the trackway whereas digit V was located towards the inside); (2) although they mentioned five digits on manus tracks, they drawed only up to four digits on their interpretative sketch (Biron and Dutuit, 1981; fig. 9 p. 412) of the trackway. The gross morphologies of *Apatopus* and *Synaptichnium* show many similarities. However,
252

*Synaptichnium* displays a compact metatarsal-phalangeal axis, which is absent amongst
*Apatopus* imprints (Klein and Lucas, 2013). *Apatopus lineatus* was described from the
Triassic deposits of the Argana Basin (Lagnaoui et al., 2012, 2016).

253

254

255

256

*Rhynchosauroides isp.*

257

Fig. 4A–D

258

259

*Material.* Numerous tracks (around a hundred) preserved as convex hyporeliefs on slabs
UCA.82 and UCA.83, Cadi Ayyad University (Marrakech).

260

261

262

263

264

265

266

267

268

269

270

271

272

*Description.* The tracks are small, pentadactyl, digitigrade to plantigrade and consist of numerous isolated pes and manus imprints (Fig. 4A–D) forming a trampled surface on slab UCA.82 (Fig. 2C). Tracks are so abundant that it was not possible to distinguish a trackway nor to clearly identify pes/manus sets. Morphology of tracks varies a lot. Only some tracks display well marked impression of all digits. In most of tracks only two or three traces of digits are present (II-IV mainly). Tracks showing five traces of digits are longer than wide, up to 2.3 cm long and up to 1.6 cm wide (Fig. 4A–D). The L/W ratio varies from 1.4 to 1.9. Digit imprints are slender, elongated, curved (sometimes straight) and show sharp claw traces. The impressions of digit increase in length from I to IV. When preserved, the impression of digit V is clearly more curved than others (Fig. 4A–D). Digits I-IV are curved inward showing a sub-parallel arrangement. Digit V is oriented outward compared to the group I-IV. The position of the impression of digit V is more proximal than those of digits I-IV. The divarication angle of digits I-V varies from 63 to 88°.

273

274

275

276

277

278

279

**Remarks.** These tracks can be confidently ascribed to *Rhynchosauroides* on the basis of the following characters: small, pentadactyl, digitigrade to plantigrade tracks; length impressions of digits increasing from I to IV; impressions of digits I-IV usually curved inward; posterolaterally positioned short digit V impression that is oriented antero-laterally. *Gwyneddichnium* differs from *Rhynchosauroides* in showing a digit proportion III > II ≥ IV > I (Klein and Lucas, 2021).

280

281

**5. Discussion**

282
252

*Synaptichnium* displays a compact metatarsal-phalangeal axis, which is absent amongst
*Apatopus* imprints (Klein and Lucas, 2013). *Apatopus lineatus* was described from the
Triassic deposits of the Argana Basin (Lagnaoui et al., 2012, 2016).

253

254

255

256

*Rhynchosauroides isp.*

257

Fig. 4A–D

258

259

*Material*. Numerous tracks (around a hundred) preserved as convex hyporeliefs on slabs
UCA.82 and UCA.83, Cadi Ayyad University (Marrakech).

260

261

262

263

264

265

266

267

268

269

270

271

272

*Description*. The tracks are small, pentadactyl, digitigrade to plantigrade and consist of numerous isolated pes and manus imprints (Fig. 4A–D) forming a trampled surface on slab UCA.82 (Fig. 2C). Tracks are so abundant that it was not possible to distinguish a trackway nor to clearly identify pes/manus sets. Morphology of tracks varies a lot. Only some tracks display well marked impression of all digits. In most of tracks only two or three traces of digits are present (II-IV mainly). Tracks showing five traces of digits are longer than wide, up to 2.3 cm long and up to 1.6 cm wide (Fig. 4A–D). The L/W ratio varies from 1.4 to 1.9. Digit imprints are slender, elongated, curved (sometimes straight) and show sharp claw traces. The impressions of digit increase in length from I to IV. When preserved, the impression of digit V is clearly more curved than others (Fig. 4A–D). Digits I-IV are curved inward showing a sub-parallel arrangement. Digit V is oriented outward compared to the group I-IV. The position of the impression of digit V is more proximal than those of digits I-IV. The divarication angle of digits I-V varies from 63 to 88°.

273

274

275

276

277

278

279

**Remarks.** These tracks can be confidently ascribed to *Rhynchosauroides* on the basis of the following characters: small, pentadactyl, digitigrade to plantigrade tracks; length impressions of digits increasing from I to IV; impressions of digits I-IV usually curved inward; postero-laterally positioned short digit V impression that is oriented antero-laterally. *Gwyneddichnium* differs from *Rhynchosauroides* in showing a digit proportion III > II ≥ IV > I (Klein and Lucas, 2021).

280

281

**5. Discussion**

282
283
284

5.1. *Ichnotaxonomic remarks on the other tetrapod tracks described by Biron and Dutuit*
(1981)

285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312

Based on a single, small and pentadactyl lacertoid footprint, Biron and Dutuit (1981) described a new ichnotaxon, "Enigmatopus atlensis" (Fig. 5A). Showing some resemblance to *Rhynchosauroides* and *Procolophonichnium*-like latertoid forms, Klein and Lucas (2021) considered this track as a *nomen dubium*. We agree with this proposition. Based on a track with bifurcated digit impressions, Biron and Dutuit (1981) erected the ichnospecies "Hyloidichnus triasicus" (Fig. 5B). *Hyloidichnus* being a Permian ichnogenus (Voigt and Lucas, 2018) with a different digit arrangement and given the fact that the description and the illustrations of Biron and Dutuit (1981) are of very poor quality without any valid arguments supporting their hypothesis, we do not consider "*H. triasicus*" as a valid ichnospecies. Biron and Dutuit (1981) described an isolated track they ascribed to a new species, "*Rectilinetopus ourikensis*" (Fig. 5C), in spite of similarities with the tracks they identified as *Apatopus lineatus*. Klein and Lucas (2013) synonymized "*Rectilinetopus ourikensis*" with *Apatopus lineatus*. We agree with this proposition since this track shares strong similarities with pes tracks of the slab UCA.83 (pes imprints pentadactyl, longer than wide; with digit imprints elongated, strait and apically pointed; impressions of digit increasing in length from I to IV; digits I-IV with a sub-parallel arrangement; large and triangular plantar-like impression).
Biron and Dutuit (1981) erected the ichnospecies "*Prochirotherium triasicum*" (Fig. 5D), for an isolated, small, pentadactyl, longer than wide, quite symmetrical track with a wide sole, and with straight and apically pointed digit impressions (impression of the digit III being the longest). They justified this assignment by similarities with tracks described as *Prochirotherium* from Permian deposits of Italy. Due to the poorness of the material described by Biron and Dutuit (1981) and the absence of diagnostic features, we consider "*P. triasicum*" as a *nomen dubium*. Based on a single isolated semi-plantigrade to plantigrade tetradactyl imprint, Biron and Dutuit (1981) erected the new species "*Pseudochirotherium oukaimedensis*" (Fig. 5E). Due to the partial preservation of tracks and the absence of diagnostic features, we consider this ichnotaxon as a *nomen dubium*. Klein and Lucas (2021) proposed that it consists of a chirotheriid track of indeterminate affinity.

313

5.2. Age of the tracksite
283
284

5.1. *Ichnotaxonomic remarks on the other tetrapod tracks described by Biron and Dutuit*
(1981)

285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312

Based on a single, small and pentadactyl lacertoid footprint, Biron and Dutuit (1981) described a new ichnotaxon, "Enigmatopus atlensis" (Fig. 5A). Showing some resemblance to *Rhynchosauroides* and *Procolophonichnium*-like latertoid forms, Klein and Lucas (2021) considered this track as a *nomen dubium*. We agree with this proposition. Based on a track with bifurcated digit impressions, Biron and Dutuit (1981) erected the ichnospecies "Hyloidichnus triasicus" (Fig. 5B). *Hyloidichnus* being a Permian ichnogenus (Voigt and Lucas, 2018) with a different digit arrangement and given the fact that the description and the illustrations of Biron and Dutuit (1981) are of very poor quality without any valid arguments supporting their hypothesis, we do not consider "*H. triasicus*" as a valid ichnospecies. Biron and Dutuit (1981) described an isolated track they ascribed to a new species, "*Rectilinetopus ourikensis*" (Fig. 5C), in spite of similarities with the tracks they identified as *Apatopus lineatus*. Klein and Lucas (2013) synonymized "*Rectilinetopus ourikensis*" with *Apatopus lineatus*. We agree with this proposition since this track shares strong similarities with pes tracks of the slab UCA.83 (pes imprints pentadactyl, longer than wide; with digit imprints elongated, strait and apically pointed; impressions of digit increasing in length from I to IV; digits I-IV with a sub-parallel arrangement; large and triangular plantar-like impression).
Biron and Dutuit (1981) erected the ichnospecies "*Prochirotherium triasicum*" (Fig. 5D), for an isolated, small, pentadactyl, longer than wide, quite symmetrical track with a wide sole, and with straight and apically pointed digit impressions (impression of the digit III being the longest). They justified this assignment by similarities with tracks described as *Prochirotherium* from Permian deposits of Italy. Due to the poorness of the material described by Biron and Dutuit (1981) and the absence of diagnostic features, we consider "*P. triasicum*" as a *nomen dubium*. Based on a single isolated semi-plantigrade to plantigrade tetradactyl imprint, Biron and Dutuit (1981) erected the new species "*Pseudochirotherium oukaimedensis*" (Fig. 5E). Due to the partial preservation of tracks and the absence of diagnostic features, we consider this ichnotaxon as a *nomen dubium*. Klein and Lucas (2021) proposed that it consists of a chirotheriid track of indeterminate affinity.

313

5.2. Age of the tracksite
All tracksites reported by Biron and Dutuit (1981) and Biron (1982) are stratigraphically located at the base of the Oukaïmeden Sandstone Fm (F5 Fm *sensu* Biron, 1982). Based on pollen analyses (Cousminer and Manspeizer, 1976; Biron and Courtinat, 1982), these deposits were considered as Late Triassic. However, based on conchostracans and new palynological data, Benaouiss et al. (2018) proposed a Ladinian-early Carnian age for the base of the Oukaïmeden Sandstone Fm. In Morocco, *Rhynchosauroides* was reported from Middle to Late Triassic in the Argana Basin (Klein et al., 2011; Lagnaoui et al., 2012, 2016; Zouheir et al., 2020). Possible *Rhynchosauroides* were also described in the Early Triassic from the same basin (Klein et al., 2010). Although *Rhynchosauroides* shows a broad stratigraphic range, extending from the middle Permian (e.g. Marchetti et al., 2022) to the Late Jurassic (Avanzini et al., 2010), the stratigraphic distribution of *Apatopus lineatus* and *Isochirotherium* are more restricted. *Apatopus lineatus* is characteristic of the Late Triassic being known from the Carnian to the Rhaetian (Klein and Lucas, 2013). In Morocco, this ichnospecies was reported from the Carnian deposits of the Argana Basin (Lagnaoui et al., 2012, 2016). *Isochirotherium* is characteristic of the Lower to the Middle Triassic with a large geographic distribution (France, Italy, Germany, Great Britain, Spain, and the USA; Klein and Haubold, 2007; Klein and Lucas, 2021 and references therein). In Morocco, *Isochirotherium coureli* was reported by Klein et al. (2011) from the Anisian-Ladinian (Middle Triassic) deposits of the Argana Basin. In conclusion, the palaeoichnological assemblage described here, as well as the palynological and conchostracean content (Benaouiss et al., 2018) from the base of the Oukaïmeden Sandstone Fm suggest a Middle-Late Triassic age. The ichnoassemblage described here displays the first documented co-occurrence of *Apatopus* and *Isochirotherium*.

337

### 5.3. Trackmakers and their paleoenvironment

Trackmakers of *Apatopus* are considered as phytosaurs (Klein and Lucas, 2013). Morphology of *Apatopus* shares similarities with crocodylian imprints, suggesting a semi-aquatic mode of life (Klein and Lucas, 2013). This contrast with the compact metatarsal-phalangeal axis typically observed amongst *Synaptichnium* whose trackmakers are supposed to be a terrestrial archosauriforms (Klein and Lucas, 2013). *Isochirotherium* is usually referred to possible crocodylian-stem archosaurs or non-crown-group archosauriforms (Klein
All tracksites reported by Biron and Dutuit (1981) and Biron (1982) are stratigraphically located at the base of the Oukaïmeden Sandstone Fm (F5 Fm *sensu* Biron, 1982). Based on pollen analyses (Cousminer and Manspeizer, 1976; Biron and Courtinat, 1982), these deposits were considered as Late Triassic. However, based on conchostracans and new palynological data, Benaouiss et al. (2018) proposed a Ladinian-early Carnian age for the base of the Oukaïmeden Sandstone Fm. In Morocco, *Rhynchosauroides* was reported from Middle to Late Triassic in the Argana Basin (Klein et al., 2011; Lagnaoui et al., 2012, 2016; Zouheir et al., 2020). Possible *Rhynchosauroides* were also described in the Early Triassic from the same basin (Klein et al., 2010). Although *Rhynchosauroides* shows a broad stratigraphic range, extending from the middle Permian (e.g. Marchetti et al., 2022) to the Late Jurassic (Avanzini et al., 2010), the stratigraphic distribution of *Apatopus lineatus* and *Isochirotherium* are more restricted. *Apatopus lineatus* is characteristic of the Late Triassic being known from the Carnian to the Rhaetian (Klein and Lucas, 2013). In Morocco, this ichnospecies was reported from the Carnian deposits of the Argana Basin (Lagnaoui et al., 2012, 2016). *Isochirotherium* is characteristic of the Lower to the Middle Triassic with a large geographic distribution (France, Italy, Germany, Great Britain, Spain, and the USA; Klein and Haubold, 2007; Klein and Lucas, 2021 and references therein). In Morocco, *Isochirotherium coureli* was reported by Klein et al. (2011) from the Anisian-Ladinian (Middle Triassic) deposits of the Argana Basin. In conclusion, the palaeoichnological assemblage described here, as well as the palynological and conchostracean content (Benaouiss et al., 2018) from the base of the Oukaïmeden Sandstone Fm suggest a Middle-Late Triassic age. The ichnoassemblage described here displays the first documented co-occurrence of *Apatopus* and *Isochirotherium*.

337

### 5.3. Trackmakers and their paleoenvironment

Trackmakers of *Apatopus* are considered as phytosaurs (Klein and Lucas, 2013). Morphology of *Apatopus* shares similarities with crocodylian imprints, suggesting a semi-aquatic mode of life (Klein and Lucas, 2013). This contrast with the compact metatarsal-phalangeal axis typically observed amongst *Synaptichnium* whose trackmakers are supposed to be a terrestrial archosauriforms (Klein and Lucas, 2013). *Isochirotherium* is usually referred to possible crocodylian-stem archosaurs or non-crown-group archosauriforms (Klein
345

346

and Lucas, 2021). Trackmakers of *Rhynchosauroides* is considered as lepidosauromorph and/or archosauromorph trackmakers (Avanzini and Renesto, 2002).

347

348

349

350

351

352

353

As mentioned by Biron and Dutuit (1981), vertebrate tracks from the Triassic deposits of the Ourika and Yagour basins are commonly associated with *Scoyenia*. This ichnogenus is interpreted as a feeding or a combined feeding and locomotion trace, produced by arthropods or annelids (Bromley and Asgaard 1979; Frey et al., 1984). The co-occurrence of these protostomian burrows and traces with tetrapod tracks matches with the *Scoyenia* ichnofacies. This latter is observed in non-marine formations commonly interpreted as subaqueous freshwater sediments (Buatois and Mángano, 1995; Buatois et al., 1997).

354

355

356

According to Fabuel-Perez et al. (2009), the lower part of the Oukaïmeden Sandstone Fm was deposited in an ephemeral fluvial system. As a result, the living environment was semi-arid, with ponds and ephemeral sediment supply.

357

358

**6. Conclusions**

359

360

361

362

-The two slabs from the Cadi Ayyad University collection bear tetrapods tracks ascribed to *Apatopus lineatus*, *Isochirotherium* isp. and *Rhynchosauroides* isp. whose trackmakers are possible phytosaurs, crocodylian-stem archosaurs or non-crown-group archosauriforms and lepidosauromorphs/archosauromorphs, respectively.

363

364

365

-All ichnotaxa created by Biron and Dutuit (1981) ("*Chirotherium atlensis*", "*Enigmatopus atlensis*", "*Hyloidichnus triasicus*", "*Prochirotherium triasicum*", "*Pseudochirotherium oukaimedensis*" and "*Rectilinetopus ourikensis*") are considered as invalid.

366

367

368

- The lithological features of the base of the Oukaïmeden Sandstone Fm as well as the presence of tetrapod walking tracks indicate that the depositional environment was a semi-arid alluvial plain with ponds, periodically flooded by ephemeral fluvial system.

369

370

371

372

- The palaeoichnological assemblage includes a mixture of Early to the Middle Triassic (*Isochirotherium*) and Late Triassic (*Apatopus lineatus*) tracks. This result corroborates the biostratigraphic data recently obtained from the base of the Oukaïmeden Sandstone Fm, suggesting a Middle-Late Triassic age.

373

374

**Declaration of competing interest**
345

346

and Lucas, 2021). Trackmakers of *Rhynchosauroides* is considered as lepidosauromorph and/or archosauromorph trackmakers (Avanzini and Renesto, 2002).

347

348

349

350

351

352

353

As mentioned by Biron and Dutuit (1981), vertebrate tracks from the Triassic deposits of the Ourika and Yagour basins are commonly associated with *Scoyenia*. This ichnogenus is interpreted as a feeding or a combined feeding and locomotion trace, produced by arthropods or annelids (Bromley and Asgaard 1979; Frey et al., 1984). The co-occurrence of these protostomian burrows and traces with tetrapod tracks matches with the *Scoyenia* ichnofacies. This latter is observed in non-marine formations commonly interpreted as subaqueous freshwater sediments (Buatois and Mángano, 1995; Buatois et al., 1997).

354

355

356

According to Fabuel-Perez et al. (2009), the lower part of the Oukaïmeden Sandstone Fm was deposited in an ephemeral fluvial system. As a result, the living environment was semi-arid, with ponds and ephemeral sediment supply.

357

358

**6. Conclusions**

359

360

361

362

-The two slabs from the Cadi Ayyad University collection bear tetrapods tracks ascribed to *Apatopus lineatus*, *Isochirotherium* isp. and *Rhynchosauroides* isp. whose trackmakers are possible phytosaurs, crocodylian-stem archosaurs or non-crown-group archosauriforms and lepidosauromorphs/archosauromorphs, respectively.

363

364

365

-All ichnotaxa created by Biron and Dutuit (1981) ("*Chirotherium atlensis*", "*Enigmatopus atlensis*", "*Hyloidichnus triasicus*", "*Prochirotherium triasicum*", "*Pseudochirotherium oukaimedensis*" and "*Rectilinetopus ourikensis*") are considered as invalid.

366

367

368

- The lithological features of the base of the Oukaïmeden Sandstone Fm as well as the presence of tetrapod walking tracks indicate that the depositional environment was a semi-arid alluvial plain with ponds, periodically flooded by ephemeral fluvial system.

369

370

371

372

- The palaeoichnological assemblage includes a mixture of Early to the Middle Triassic (*Isochirotherium*) and Late Triassic (*Apatopus lineatus*) tracks. This result corroborates the biostratigraphic data recently obtained from the base of the Oukaïmeden Sandstone Fm, suggesting a Middle-Late Triassic age.

373

374

**Declaration of competing interest**
375

376

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

377

378

Data availability

379

Data will be made available on request.

380

381

Acknowledgments

382

383

384

385

The authors are grateful to Moulay Ahmed Boumehdi, head of the department of Geology at Cadi Ayyad University Marrakech for the access to the collection room housing the studied slabs. We also thank Spencer G. Lucas and the anonymous reviewer for their constructive and thoughtful reviews on the manuscript.

386

387

References

388

389

390

391

392

393

394

395

396

397

Avanzini, M., Renesto, S., 2002, A review of *Rhynchosauroides tirolicus* Abel, 1926
ichnospecies (Middle Triassic: Anisian-Ladinian) and some inferences on
*Rhynchosauroides* trackmaker. Riv. Ital. di Paleontol. e Stratigr. 108, 51–66.

Avanzini, M., Piñuela, L., Garcia-Ramos, J.C., 2010. First report of a Late Jurassic lizard-like footprint (Asturias, Spain). J. Iber. Geol. 36, 175–180.

Baudon, C., Fabuel-Perez, I., Redfern, J., 2009. Structural style and evolution of a Late Triassic rift basin in the Central High Atlas, Morocco: controls on sediment deposition. Geol. J. 44, 677–691.

Beauchamp, J., 1988. Triassic sedimentation and rifting in the High Atlas (Morocco). Dev. Geotecton. 22, 477–497.

Benaouiss, N., Courel, L., Beauchamp, J., 1996. Rift-controlled fluvial/tidal transitional series in the Oukaïmeden Sandstones, High Atlas of Marrakesh (Morocco). Sed. Geol. 107, 21–36.

400

401

402
375

376

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

377

378

**Data availability**

379

Data will be made available on request.

380

381

**Acknowledgments**

382

383

384

385

The authors are grateful to Moulay Ahmed Boumehdi, head of the department of Geology at Cadi Ayyad University Marrakech for the access to the collection room housing the studied slabs. We also thank Spencer G. Lucas and the anonymous reviewer for their constructive and thoughtful reviews on the manuscript.

386

387

**References**

388

389

390

Avanzini, M., Renesto, S., 2002, A review of *Rhynchosauroides tirolicus* Abel, 1926
ichnospecies (Middle Triassic: Anisian-Ladinian) and some inferences on
*Rhynchosauroides* trackmaker. Riv. Ital. di Paleontol. e Stratigr. 108, 51–66.

391

392

393

Avanzini, M., Piñuela, L., Garcia-Ramos, J.C., 2010. First report of a Late Jurassic lizard-like footprint (Asturias, Spain). J. Iber. Geol. 36, 175–180.

394

395

396

397

Baudon, C., Fabuel-Perez, I., Redfern, J., 2009. Structural style and evolution of a Late Triassic rift basin in the Central High Atlas, Morocco: controls on sediment deposition. Geol. J. 44, 677–691.

398

399

Beauchamp, J., 1988. Triassic sedimentation and rifting in the High Atlas (Morocco). Dev. Geotecton. 22, 477–497.

400

401

402

Benaouiss, N., Courel, L., Beauchamp, J., 1996. Rift-controlled fluvial/tidal transitional series in the Oukaïmeden Sandstones, High Atlas of Marrakesh (Morocco). Sed. Geol. 107, 21–36.
403 Benaouiss, N., Juncal, M., Bourquin, S., Tourani, A., Broutin, J., Diez, J.-B., 2018. New
404 biostratigraphical records in the Permian and Triassic basins, High Atlas of
405 Marrakech, Morocco. 2nd International Congress on Permian and Triassic, 19–20.

406 Benaouiss, N., Tourani, A., Bourquin, S., Jalil, N.-E., 2023. Late Permian to early Middle
407 Triassic palaeoenvironmental reconstructions of the High Atlas, Morocco:
408 Geodynamic and climate implications in the intertropical western Peri-Tethyan
409 domain. Palaeogeogr. Palaeoclimatol. Palaeoecol. 630, 111809.

410 Bertrand, H., Dostal, J., Dupuy, C., 1982. Geochemistry of early Mesozoic tholeiites from
411 Morocco. Earth Planet. Sci. Lett. 58, 225–239.

412 Biron, P. E., 1982. Le Permo-Trias de la région de l'Ourika (Haut-Atlas de Marrakech,
413 Maroc): lithostratigraphie, sédimentologie, tectonique et minéralisations. Université de
414 Grenoble, France. Unpublished PhD diss.

415 Biron, P.E., Dutuit, J., 1981. Figurations sédimentaires et traces d'activité au sol dans le Trias
416 de la formation d'Argana et de l'Ourika (Maroc): Bull. Mus. Hist. Nat. Paris 4, 399–
417 427.

418 Biron, P.E., Courtinat, B., 1982. Contribution palynologique à la connaissance du Trias du
419 Haut Atlas de Marrakech. Geobios 15, 231–235.

420 Blackburn, T.J., Olsen, P.E., Bowring, S.A., McLean, N.M., Kent, D.V., Puffer, J., McHone,
421 G., Rasbury, E.T., Et-Touhami, M., 2013. Zircon U-Pb Geochronology Links the End-
422 Triassic Extinction with the Central Atlantic Magmatic Province. Science 340, 941–
423 945.

424 Bock, W., 1952. Triassic reptilian tracks and trends of locomotive evolution. J. Paleontol. 26,
425 395–433.

426 Bromley, R., Asgaard, U., 1979. Triassic freshwater ichnocoenoses from Carlsberg Fjord, east
427 Greenland. Palaeogeogr. Palaeoclimatol. Palaeoecol. 28, 39–80.

428 Buatois, L. A., Mángano, M.G., 1995. The paleoenvironmental and paleoecological
429 significance of the lacustrine Mermia ichnofacies: an archetypical subaqueous
430 nonmarine trace fossil assemblage. Ichnos 4, 151–161.
403 Benaouiss, N., Juncal, M., Bourquin, S., Tourani, A., Broutin, J., Diez, J.-B., 2018. New
404 biostratigraphical records in the Permian and Triassic basins, High Atlas of
405 Marrakech, Morocco. 2nd International Congress on Permian and Triassic, 19–20.

406 Benaouiss, N., Tourani, A., Bourquin, S., Jalil, N.-E., 2023. Late Permian to early Middle
407 Triassic palaeoenvironmental reconstructions of the High Atlas, Morocco:
408 Geodynamic and climate implications in the intertropical western Peri-Tethyan
409 domain. Palaeogeogr. Palaeoclimatol. Palaeoecol. 630, 111809.

410 Bertrand, H., Dostal, J., Dupuy, C., 1982. Geochemistry of early Mesozoic tholeiites from
411 Morocco. Earth Planet. Sci. Lett. 58, 225–239.

412 Biron, P. E., 1982. Le Permo-Trias de la région de l'Ourika (Haut-Atlas de Marrakech,
413 Maroc): lithostratigraphie, sédimentologie, tectonique et minéralisations. Université de
414 Grenoble, France. Unpublished PhD diss.

415 Biron, P.E., Dutuit, J., 1981. Figurations sédimentaires et traces d'activité au sol dans le Trias
416 de la formation d'Argana et de l'Ourika (Maroc): Bull. Mus. Hist. Nat. Paris 4, 399–
417 427.

418 Biron, P.E., Courtinat, B., 1982. Contribution palynologique à la connaissance du Trias du
419 Haut Atlas de Marrakech. Geobios 15, 231–235.

420 Blackburn, T.J., Olsen, P.E., Bowring, S.A., McLean, N.M., Kent, D.V., Puffer, J., McHone,
421 G., Rasbury, E.T., Et-Touhami, M., 2013. Zircon U-Pb Geochronology Links the End-
422 Triassic Extinction with the Central Atlantic Magmatic Province. Science 340, 941–
423 945.

424 Bock, W., 1952. Triassic reptilian tracks and trends of locomotive evolution. J. Paleontol. 26,
425 395–433.

426 Bromley, R., Asgaard, U., 1979. Triassic freshwater ichnocoenoses from Carlsberg Fjord, east
427 Greenland. Palaeogeogr. Palaeoclimatol. Palaeoecol. 28, 39–80.

428 Buatois, L. A., Mángano, M.G., 1995. The paleoenvironmental and paleoecological
429 significance of the lacustrine Mermia ichnofacies: an archetypical subaqueous
430 nonmarine trace fossil assemblage. Ichnos 4, 151–161.
431 Buatois, L.A., Mángano, M.G., Maples, C.G., 1997. The paradox of nonmarine ichnofaunas
432 in tidal rhythmites; integrating sedimentologic and ichnologic data from the Late
433 Cretaceous of eastern Kansas, USA. Palaios 12, 467–481.

434 Cousminer, H.L., Manspeizer, W., 1976. Triassic pollen date Moroccan High Atlas and the
435 incipient rifting of Pangea as middle Carnian. Science 191, 943–945.

436 De Pachtère, P., 1983. Le volcanisme permien et fini-triasique dans le Haut-Atlas de
437 Marrakech (Maroc): Approche pétrologique et géochimique. Université de Grenoble,
438 France. Unpublished PhD diss.

439 El Arabi, E.H., 1988. Le Permo-Trias du flanc sud du Haut Atlas de Marrakech.
440 Sédimentologie, cartographie et paléogéographie. Université de Grenoble, France.
441 Unpublished PhD diss.

442 El Arabi, E.H., Ferrandini, J., Essamoud, R., 2003. Triassic stratigraphy and structural
443 evolution of a rift basin: the Eç Çour basin, High Atlas of Marrakech, Morocco. J. Afr.
444 Earth Sci. 36, 29–39.

445 El Arabi, E.H., Diez, J.B., Broutin, J., Essamoud, R., 2006. Première caractérisation
446 palynologique du Trias moyen dans le Haut Atlas ; implications pour l'initiation du
447 rifting téthysien au Maroc. C. R. Geoscience 338, 641-649.

448 Fabuel-Perez, I., Redfern, J., Hodgetts, D., 2009. Sedimentology of an intra-montane rift-
449 controlled fluvial dominated succession: the Upper Triassic Oukaimeden Sandstone
450 Formation, Central High Atlas, Morocco. Sediment. Geol. 218, 103-140.

451 Fichter, J., Kunz, R., 2004. New genus and species of chirotheroid tracks in the Detyurth-
452 Formation (Middle Bunter, Lower Triassic) of Central Germany. Ichnos 11, 183–193.

453 Frey, R.W., Pemberton, S.G., Fagerstrom, J.A., 1984. Morphological, ethological, and
454 environmental significance of the ichnogenera *Scoyenia* and *Ancorichnus*. J. Paleontol.
455 58, 511–528.

456
457 Haubold, H. 1971. Ichnia Amphibiorum et Reptiliorum fossilium. Handb. Paläoherpetol. 18,
458 1–124.
431 Buatois, L.A., Mángano, M.G., Maples, C.G., 1997. The paradox of nonmarine ichnofaunas
432 in tidal rhythmites; integrating sedimentologic and ichnologic data from the Late
433 Cretaceous of eastern Kansas, USA. Palaios 12, 467–481.

434 Cousminer, H.L., Manspeizer, W., 1976. Triassic pollen date Moroccan High Atlas and the
435 incipient rifting of Pangea as middle Carnian. Science 191, 943–945.

436 De Pachtère, P., 1983. Le volcanisme permien et fini-triasique dans le Haut-Atlas de
437 Marrakech (Maroc): Approche pétrologique et géochimique. Université de Grenoble,
438 France. Unpublished PhD diss.

439 El Arabi, E.H., 1988. Le Permo-Trias du flanc sud du Haut Atlas de Marrakech.
440 Sédimentologie, cartographie et paléogéographie. Université de Grenoble, France.
441 Unpublished PhD diss.

442 El Arabi, E.H., Ferrandini, J., Essamoud, R., 2003. Triassic stratigraphy and structural
443 evolution of a rift basin: the Eç Çour basin, High Atlas of Marrakech, Morocco. J. Afr.
444 Earth Sci. 36, 29–39.

445 El Arabi, E.H., Diez, J.B., Broutin, J., Essamoud, R., 2006. Première caractérisation
446 palynologique du Trias moyen dans le Haut Atlas ; implications pour l'initiation du
447 rifting téthysien au Maroc. C. R. Geoscience 338, 641-649.

448 Fabuel-Perez, I., Redfern, J., Hodgetts, D., 2009. Sedimentology of an intra-montane rift-
449 controlled fluvial dominated succession: the Upper Triassic Oukaimeden Sandstone
450 Formation, Central High Atlas, Morocco. Sediment. Geol. 218, 103-140.

451 Fichter, J., Kunz, R., 2004. New genus and species of chirotheroid tracks in the Detyrth-
452 Formation (Middle Bunter, Lower Triassic) of Central Germany. Ichnos 11, 183–193.

453 Frey, R.W., Pemberton, S.G., Fagerstrom, J.A., 1984. Morphological, ethological, and
454 environmental significance of the ichnogenera *Scojenia* and *Ancorichnus*. J. Paleontol.
455 58, 511–528.

456
457 Haubold, H. 1971. Ichnia Amphibiorum et Reptiliorum fossilium. Handb. Paläoherpetol. 18,
458 1–124.
459

Hminna, A., Voigt, S., Klein, H., Saber, H., Schneider, J.W., Hmich, D., 2013. First occurrence of tetrapod footprints from the continental Triassic of the Sidi Said Maachou area (Western Meseta, Morocco). *J. Afr. Earth Sci.* 80, 1–7.

460

461

462

Hminna, A., Lagnaoui, A., Zouheir, T., Saber, H., Schneider, J.W., 2020. Late Triassic ichnoassemblage from a playa-lake system of the Coastal Meseta, Morocco: Palaeoenvironmental and palaeoecological implications. *J. Afr. Earth Sci.* 172, 103995.

463

464

465

466

Hminna, A., Klein, H., Zouheir, T., Lagnaoui, A., Saber, H., Lallensack, J. N., Oukassou, M., 2021. The Late Triassic archosaur ichnogenus *Brachychirotherium*: first complete step cycles from Morocco, North Africa, with implications for trackmaker identification and ichnotaxonomy. *Hist. Biol.* 33, 723–736.

467

468

469

470

Klein, H., Haubold, H., 2007. Archosaur footprints – Potential for biochronology of Triassic continental sequences. *New Mexico Mus. Nat. Hist. Sci. Bull.* 41, 120–130.

471

472

Klein, H., Lucas, S.G., 2013. The Late Triassic tetrapod ichnotaxon *Apatopus lineatus* (Bock 1952) and its distribution. *New Mexico Mus. Nat. Hist. Sci. Bull.* 61, 313–324.

473

474

Klein, H., Lucas, S.G., 2021. The Triassic tetrapod footprint record. *New Mexico Mus. Nat. Hist. Sci. Bull.* 83, 1–194.

475

476

Klein, H., Voigt, S., Hminna, A., Saber, H., Schneider, J., Hmich, D., 2010. Early Triassic archosaur-dominated footprint assemblage from the Argana Basin (western High Atlas, Morocco). *Ichnos* 17, 215–227.

477

478

479

Klein, H., Voigt, S., Saber, H., Schneider, J.W., Hminna, A., Fischer, J., Lagnaoui, A., Brosig, A., 2011. First occurrence of a Middle Triassic tetrapod ichnofauna from the Argana Basin (western High Atlas, Morocco). *Palaeogeogr. Palaeoclimatol. Palaeoecol.* 307, 218–231.

480

481

482

483

Klein, H., Niedźwiedzki, G., Voigt, S., Lagnaoui, A., Hminna, A., Saber, H., Schneider, J.W., 2013. The tetrapod ichnogenus *Protochirotherium* Fichter and Kunz 2004, a characteristic Early Triassic morphotype of central Pangea. *Ichnos* 20, 24–30.

484

485
459

Hminna, A., Voigt, S., Klein, H., Saber, H., Schneider, J.W., Hmich, D., 2013. First occurrence of tetrapod footprints from the continental Triassic of the Sidi Said Maachou area (Western Meseta, Morocco). *J. Afr. Earth Sci.* 80, 1–7.

460

461

462

Hminna, A., Lagnaoui, A., Zouheir, T., Saber, H., Schneider, J.W., 2020. Late Triassic ichnoassemblage from a playa-lake system of the Coastal Meseta, Morocco: Palaeoenvironmental and palaeoecological implications. *J. Afr. Earth Sci.* 172, 103995.

463

464

465

466

Hminna, A., Klein, H., Zouheir, T., Lagnaoui, A., Saber, H., Lallensack, J. N., Oukassou, M., 2021. The Late Triassic archosaur ichnogenus *Brachychirotherium*: first complete step cycles from Morocco, North Africa, with implications for trackmaker identification and ichnotaxonomy. *Hist. Biol.* 33, 723–736.

467

468

469

470

Klein, H., Haubold, H., 2007. Archosaur footprints – Potential for biochronology of Triassic continental sequences. *New Mexico Mus. Nat. Hist. Sci. Bull.* 41, 120–130.

471

472

Klein, H., Lucas, S.G., 2013. The Late Triassic tetrapod ichnotaxon *Apatopus lineatus* (Bock 1952) and its distribution. *New Mexico Mus. Nat. Hist. Sci. Bull.* 61, 313–324.

473

474

Klein, H., Lucas, S.G., 2021. The Triassic tetrapod footprint record. *New Mexico Mus. Nat. Hist. Sci. Bull.* 83, 1–194.

475

476

Klein, H., Voigt, S., Hminna, A., Saber, H., Schneider, J., Hmich, D., 2010. Early Triassic archosaur-dominated footprint assemblage from the Argana Basin (western High Atlas, Morocco). *Ichnos* 17, 215–227.

477

478

479

Klein, H., Voigt, S., Saber, H., Schneider, J.W., Hminna, A., Fischer, J., Lagnaoui, A., Brosig, A., 2011. First occurrence of a Middle Triassic tetrapod ichnofauna from the Argana Basin (western High Atlas, Morocco). *Palaeogeogr. Palaeoclimatol. Palaeoecol.* 307, 218–231.

480

481

482

483

Klein, H., Niedźwiedzki, G., Voigt, S., Lagnaoui, A., Hminna, A., Saber, H., Schneider, J.W., 2013. The tetrapod ichnogenus *Protochirotherium* Fichter and Kunz 2004, a characteristic Early Triassic morphotype of central Pangea. *Ichnos* 20, 24–30.

484

485
486 Lagnaoui, A., Klein, H., Voigt, S., Hminna, A., Saber, H., Schneider, J. W., Werneburg, R., 2012. Late Triassic tetrapod-dominated ichnoassemblages from the Argana Basin (Western High Atlas, Morocco). *Ichnos* 19, 238–253.

489 Lagnaoui, A., Klein, H., Saber, H., Fekkak, A., Belahmira, A., Schneider, J.W., 2016. New discoveries of archosaur and other tetrapod footprints from the Timezgadiouine Formation (Irohalene Member, Upper Triassic) of the Argana Basin, western High Atlas, Morocco–Ichnotaxonomic implications. *Palaeogeogr. Palaeoclimatol. Palaeoecol.* 453, 1–9.

494 Laville, E., Petit, J.-P., 1984. Role of synsedimentary strike-slip faults in the formation of Moroccan Triassic basins. *Geology* 12, 424–427.

496 Laville, E., Piqué, A., 1991. La Distension crustale atlantique et atlasique au Maroc au début du Mésozoïque; le rejeu des structures hercyniennes. *Bull. Soc. Géol. Fr.* 162, 1161–1171.

499 Leonardi, G., 1987. Glossary and manual of tetrapod footprint palaeoichnology. *Ministerio Minas Energie, Departamento Nacional da Produção Mineral, Brasília*.

501 Marchetti, L., Logghe, A., Mujal, E., Barrier, P., Montenat, C., Nel, A., J-M, Pouillon, R. 502 Garrouste, J.S., Steyer, 2022. Vertebrate tracks from the Permian of Gonfaron 503 (Provence, Southern France) and their implications for the late Capitanian terrestrial 504 extinction event. *Palaeogeography, Palaeoclimatology, Palaeoecology*, 599, 111043.

505 Marzoli, A., Bertrand, H., Knight, K.B., Cirilli, S., Buratti, N., Vérati, C., Nomade, S., 506 Renne, P.R., Youbi, N., Martini, R., 2004. Synchrony of the Central Atlantic 507 magmatic province and the Triassic-Jurassic boundary climatic and biotic crisis. 508 *Geology* 32, 973–976.

509 Mattis, A.F., 1977. Nonmarine Triassic sedimentation, central High Atlas Mountains, 510 Morocco. *J. Sediment. Petrol.* 47, 107–119.

511 Perez, N.D., Teixell, A., Gómez-Gras, D., Stockli, D.F., 2019. Reconstructing Extensional 512 Basin Architecture and Provenance in the Marrakech High Atlas of Morocco: 513 Implications for Rift Basins and Inversion Tectonics. *Tectonics* 38, 1584–1608.
486 Lagnaoui, A., Klein, H., Voigt, S., Hminna, A., Saber, H., Schneider, J. W., Werneburg, R., 2012. Late Triassic tetrapod-dominated ichnoassemblages from the Argana Basin (Western High Atlas, Morocco). *Ichnos* 19, 238–253.

489 Lagnaoui, A., Klein, H., Saber, H., Fekkak, A., Belahmira, A., Schneider, J.W., 2016. New discoveries of archosaur and other tetrapod footprints from the Timezgadiouine Formation (Irohalene Member, Upper Triassic) of the Argana Basin, western High Atlas, Morocco–Ichnotaxonomic implications. *Palaeogeogr. Palaeoclimatol. Palaeoecol.* 453, 1–9.

494 Laville, E., Petit, J.-P., 1984. Role of synsedimentary strike-slip faults in the formation of Moroccan Triassic basins. *Geology* 12, 424–427.

496 Laville, E., Piqué, A., 1991. La Distension crustale atlantique et atlasique au Maroc au début du Mésozoïque; le rejeu des structures hercyniennes. *Bull. Soc. Géol. Fr.* 162, 1161–1171.

499 Leonardi, G., 1987. Glossary and manual of tetrapod footprint palaeoichnology. *Ministerio Minas Energie, Departamento Nacional da Produção Mineral, Brasília*.

501 Marchetti, L., Logghe, A., Mujal, E., Barrier, P., Montenat, C., Nel, A., J-M, Pouillon, R. 502 Garrouste, J.S., Steyer, 2022. Vertebrate tracks from the Permian of Gonfaron 503 (Provence, Southern France) and their implications for the late Capitanian terrestrial 504 extinction event. *Palaeogeography, Palaeoclimatology, Palaeoecology*, 599, 111043.

505 Marzoli, A., Bertrand, H., Knight, K.B., Cirilli, S., Buratti, N., Vérati, C., Nomade, S., 506 Renne, P.R., Youbi, N., Martini, R., 2004. Synchrony of the Central Atlantic 507 magmatic province and the Triassic-Jurassic boundary climatic and biotic crisis. 508 *Geology* 32, 973–976.

509 Mattis, A.F., 1977. Nonmarine Triassic sedimentation, central High Atlas Mountains, 510 Morocco. *J. Sediment. Petrol.* 47, 107–119.

511 Perez, N.D., Teixell, A., Gómez-Gras, D., Stockli, D.F., 2019. Reconstructing Extensional 512 Basin Architecture and Provenance in the Marrakech High Atlas of Morocco: 513 Implications for Rift Basins and Inversion Tectonics. *Tectonics* 38, 1584–1608.
514

Qarbous, A., Medina, F., Hoepffner, C., 2003. Le bassin de Tizi n'Test (Haut Atlas, Maroc) :
exemple d'évolution d'un segment oblique au rift de l'Atlantique central au Trias.
Can. J. Earth Sci. 40, 949-964.

515

516

517

Tourani, A., Benaouiss, N., Gand, G., Bourquin, S., Jalil, N.-E., Broutin, J., Battail, B.,
Germain, D., Khaldoune, F., Sebban, S., Steyer, J.-C., Vacant, R., 2010. Evidence of
an Early Triassic age (Olenekian) in Argana Basin (High Atlas, Morocco) based on
new chirotherioid traces. C. R. Palevol 9, 201-208.

518

519

520

521

Tourani, A., Benaouiss, N., De la Horra, R., Barrenechea, J. F., Lopez-Gomez, J., Gallego, O.
F., Bourquin, S., 2023. Characterization of the Carnian Pluvial Episode in the Argana
Basin (Western High Atlas, Morocco): An approach based on sedimentology, clay
mineralogy and paleosols. Palaeogeogr. Palaeoclimatol. Palaeoecol. 627, 111720.

522

523

524

525

Van Houten, F.B., 1977. Triassic-Liassic deposits of Morocco and East North America: A
comparison. Bull. Am. Assoc. Pet. Geol. 61, 79-99.

526

527

Voigt, S., Lucas, S.G., 2018. Outline of a Permian tetrapod footprint ichnostratigraphy. Geol.
Soc. Spec. Publ. 450, 387-404.

528

529

Weems, R. E., Lucas, S.G., 2015. A revision of the Norian conchostracan zonation in North
America and its implications for Late Triassic North American tectonic history. New
Mexico Mus. Nat. Hist. Sci. Bull. 67, 303-318.

530

531

532

Zouheir, T., Hminna, A., Klein, H., Lagnaoui, A., Saber, H., Schneider, J.W., 2020. Unusual
archosaur trackway and associated tetrapod ichnofauna from Irohalene member
(Timezgadiouine Formation, late Triassic, Carnian) of the Argana Basin, Western
High Atlas, Morocco. Hist. Biol. 32, 589-601.

533

534

535

536

537

538

539

540

541
514

Qarbous, A., Medina, F., Hoepffner, C., 2003. Le bassin de Tizi n'Test (Haut Atlas, Maroc) :
exemple d'évolution d'un segment oblique au rift de l'Atlantique central au Trias.
Can. J. Earth Sci. 40, 949-964.

515

516

517

Tourani, A., Benaouiss, N., Gand, G., Bourquin, S., Jalil, N.-E., Broutin, J., Battail, B.,
Germain, D., Khaldoune, F., Sebban, S., Steyer, J.-C., Vacant, R., 2010. Evidence of
an Early Triassic age (Olenekian) in Argana Basin (High Atlas, Morocco) based on
new chirotherioid traces. C. R. Palevol 9, 201-208.

518

519

520

521

Tourani, A., Benaouiss, N., De la Horra, R., Barrenechea, J. F., Lopez-Gomez, J., Gallego, O.
F., Bourquin, S., 2023. Characterization of the Carnian Pluvial Episode in the Argana
Basin (Western High Atlas, Morocco): An approach based on sedimentology, clay
mineralogy and paleosols. Palaeogeogr. Palaeoclimatol. Palaeoecol. 627, 111720.

522

523

524

525

Van Houten, F.B., 1977. Triassic-Liassic deposits of Morocco and East North America: A
comparison. Bull. Am. Assoc. Pet. Geol. 61, 79-99.

526

527

Voigt, S., Lucas, S.G., 2018. Outline of a Permian tetrapod footprint ichnostratigraphy. Geol.
Soc. Spec. Publ. 450, 387-404.

528

529

Weems, R. E., Lucas, S.G., 2015. A revision of the Norian conchostracan zonation in North
America and its implications for Late Triassic North American tectonic history. New
Mexico Mus. Nat. Hist. Sci. Bull. 67, 303-318.

530

531

532

Zouheir, T., Hminna, A., Klein, H., Lagnaoui, A., Saber, H., Schneider, J.W., 2020. Unusual
archosaur trackway and associated tetrapod ichnofauna from Irohalene member
(Timezgadiouine Formation, late Triassic, Carnian) of the Argana Basin, Western
High Atlas, Morocco. Hist. Biol. 32, 589-601.

533

534

535

536

537

538

539

540

541
542 **Figure captions**

543

544 **Fig. 1.** Geological and stratigraphical setting of Marrakech High Atlas around the Ourika and
545 Yagour basins. **A**, Permian and Triassic outcrops throughout the High Atlas:

546 CHA = Central High Atlas, EHA = Eastern High Atlas, MA = Middle Atlas, MHA =
547 Marrakech High Atlas and WHA = Western High Atlas (modified after Beauchamp, 1988;
548 Laville and Piqué, 1991). Rectangle indicates the study area. **B**, geological map modified after
549 Biron (1982), showing tetrapod trackway sites marked by stars with number: (1) East of
550 Aghbalou, (2) North-East of Anammer, and (3) NW of Yagour Plateau. **C**, Simplified
551 lithostratigraphic column of the MHA area (F1 to F6 Fm). The studied interval is localised at
552 the base of the F5 Fm. (1) early Permian (radioactive and zircon method, Van Houten, 1977);
553 (2) middle Anisian (from pollens, El Arabi et al., 2006); (3) middle Carnian (from pollens,
554 Biron and Courtinat, 1982); (4) Ladinian-early Carnian (from pollens and conchostracans;
555 Benaouiss et al., 2018); (5) middle Carnian (from pollens; Cousminer and Manspeizer, 1976).

556

557 **Fig. 2. Isochirotherium. A–C**, Slab UCA.82 bearing several consecutive pes/manus sets (P.,
558 pes track; M., manus track), photograph (A), photogrammetric 3D mesh (B) and interpretative
559 sketch (C); the red dotted line indicates the axis of the partial trackway. **D–F**, Pes/manus set;
560 photograph (D), digital elevation model in false colours (E) and interpretative sketch (F).
561 Convex hyporeliefs. **G–H**, details of the skin trace; photograph (G), and interpretative sketch
562 (H).

563

564 **Fig. 3. Apatopus lineatus. A–C**, Slab UCA.83. bearing several consecutive pes/manus sets,
565 two of them forming a trackway (blue dots) (LP. left pes track, LM. left manus track, RP.
566 right pes track, RM. right manus track), photograph (A), photogrammetric 3D mesh (B) and
567 interpretative sketch (C). **D–G**, Two pes/manus sets; photograph (D, F) and interpretative
568 sketches (E, G). Convex hyporeliefs.

569
542 **Figure captions**

543

544 **Fig. 1.** Geological and stratigraphical setting of Marrakech High Atlas around the Ourika and
545 Yagour basins. **A**, Permian and Triassic outcrops throughout the High Atlas:

546 CHA = Central High Atlas, EHA = Eastern High Atlas, MA = Middle Atlas, MHA =
547 Marrakech High Atlas and WHA = Western High Atlas (modified after Beauchamp, 1988;
548 Laville and Piqué, 1991). Rectangle indicates the study area. **B**, geological map modified after
549 Biron (1982), showing tetrapod trackway sites marked by stars with number: (1) East of
550 Aghbalou, (2) North-East of Anammer, and (3) NW of Yagour Plateau. **C**, Simplified
551 lithostratigraphic column of the MHA area (F1 to F6 Fm). The studied interval is localised at
552 the base of the F5 Fm. (1) early Permian (radioactive and zircon method, Van Houten, 1977);
553 (2) middle Anisian (from pollens, El Arabi et al., 2006); (3) middle Carnian (from pollens,
554 Biron and Courtinat, 1982); (4) Ladinian-early Carnian (from pollens and conchostracans;
555 Benaouiss et al., 2018); (5) middle Carnian (from pollens; Cousminer and Manspeizer, 1976).

556

557 **Fig. 2. Isochirotherium. A–C**, Slab UCA.82 bearing several consecutive pes/manus sets (P.,
558 pes track; M., manus track), photograph (A), photogrammetric 3D mesh (B) and interpretative
559 sketch (C); the red dotted line indicates the axis of the partial trackway. **D–F**, Pes/manus set;
560 photograph (D), digital elevation model in false colours (E) and interpretative sketch (F).
561 Convex hyporeliefs. **G–H**, details of the skin trace; photograph (G), and interpretative sketch
562 (H).

563

564 **Fig. 3. Apatopus lineatus. A–C**, Slab UCA.83. bearing several consecutive pes/manus sets,
565 two of them forming a trackway (blue dots) (LP. left pes track, LM. left manus track, RP.
566 right pes track, RM. right manus track), photograph (A), photogrammetric 3D mesh (B) and
567 interpretative sketch (C). **D–G**, Two pes/manus sets; photograph (D, F) and interpretative
568 sketches (E, G). Convex hyporeliefs.

569
570

**Fig. 4.** *Rhynchosauroides* isp., two tracks from the slab UCA.82. **A–D**, Isolated tracks, photographs (A, C) and interpretative sketch (B, D). Convex hyporeliefs.

571

572

573

**Fig. 5.** Invalid or problematic ichnotaxa reported by Biron and Dutuit (1981) in the Triassic of the Ourika-Yagour basins. **A**, “*Enigmatopus atlensis*” (invalid ichnotaxon in this study). **B**, “*Hyloidichnus triasicus*” (nomen dubium in this study). **C**, “*Rectilinetopus ourikensis*” (*Apatopus lineatus* in this study). **D**, “*Prochirotherium triasicum*” (nomen dubium in this study). **E**, “*Pseudochirotherium oukaimedensis*” (nomen dubium in this study).

574

575

576

577

578

579

**Fig. 6.** Comparison between some Triassic Chirotherian tracks. **A**, *Brachychirotherium*, Late Triassic, Germany. **B**, *Isochirotherium lomasi*, Middle Triassic, Great Britain. **C**, *Chirotherium* (“*Parachirotherium*”), Middle Triassic, Germany. **D**, *Protochirotherium*, Early Triassic, Germany. **E**, *Synaptichnium*, Middle Triassic, Great Britain. Modified after Klein and Lucas (2021).

580

581

582

583

584
570

571

**Fig. 4.** *Rhynchosauroides* isp., two tracks from the slab UCA.82. **A–D**, Isolated tracks, photographs (A, C) and interpretative sketch (B, D). Convex hyporeliefs.

572

573

574

575

576

577

**Fig. 5.** Invalid or problematic ichnotaxa reported by Biron and Dutuit (1981) in the Triassic of the Ourika-Yagour basins. **A**, “*Enigmatopus atlensis*” (invalid ichnotaxon in this study). **B**, “*Hyloidichnus triasicus*” (nomen dubium in this study). **C**, “*Rectilinetopus ourikensis*” (*Apatopus lineatus* in this study). **D**, “*Prochirotherium triasicum*” (nomen dubium in this study). **E**, “*Pseudochirotherium oukaimedensis*” (nomen dubium in this study).

578

579

580

581

582

583

**Fig. 6.** Comparison between some Triassic Chirotherian tracks. **A**, *Brachychirotherium*, Late Triassic, Germany. **B**, *Isochirotherium lomasi*, Middle Triassic, Great Britain. **C**, *Chirotherium* (“*Parachirotherium*”), Middle Triassic, Germany. **D**, *Protochirotherium*, Early Triassic, Germany. **E**, *Synaptichnium*, Middle Triassic, Great Britain. Modified after Klein and Lucas (2021).

584
<figure><img src="image_3.png" /></figure>

<figure><img src="image_4.png" /></figure>
<figure><img src="image_4.png" /></figure>

<figure><img src="image_5.png" /></figure>
A

<figure><img src="image_5.png" /></figure>

B

<figure><img src="image_6.png" /></figure>

C

<figure><img src="image_7.png" /></figure>

D

<figure><img src="image_8.png" /></figure>

E

<figure><img src="image_9.png" /></figure>

F

<figure><img src="image_10.png" /></figure>

G

<figure><img src="image_11.png" /></figure>
A

<figure><img src="image_6.png" /></figure>

B

<figure><img src="image_7.png" /></figure>

C

<figure><img src="image_8.png" /></figure>

D

<figure><img src="image_9.png" /></figure>

E

<figure><img src="image_10.png" /></figure>

F

<figure><img src="image_11.png" /></figure>

G

<figure><img src="image_12.png" /></figure>
<figure><img src="image_12.png" /></figure>

<figure><img src="image_13.png" /></figure>

<figure><img src="image_14.png" /></figure>

<figure><img src="image_15.png" /></figure>

<figure><img src="image_16.png" /></figure>
<figure><img src="image_13.png" /></figure>

<figure><img src="image_14.png" /></figure>

<figure><img src="image_15.png" /></figure>

<figure><img src="image_16.png" /></figure>

<figure><img src="image_17.png" /></figure>
<figure><img src="image_17.png" /></figure>

<figure><img src="image_18.png" /></figure>

<figure><img src="image_19.png" /></figure>

<figure><img src="image_20.png" /></figure>

<figure><img src="image_21.png" /></figure>
<figure><img src="image_18.png" /></figure>

<figure><img src="image_19.png" /></figure>

<figure><img src="image_20.png" /></figure>

<figure><img src="image_21.png" /></figure>

<figure><img src="image_22.png" /></figure>
A

<figure><img src="image_22.png" /></figure>

B

<figure><img src="image_23.png" /></figure>

C

<figure><img src="image_24.png" /></figure>

D

<figure><img src="image_25.png" /></figure>

E

<figure><img src="image_26.png" /></figure>

10 cm

<figure><img src="image_27.png" /></figure>
A

<figure><img src="image_23.png" /></figure>

B

<figure><img src="image_24.png" /></figure>

C

<figure><img src="image_25.png" /></figure>

D

<figure><img src="image_26.png" /></figure>

E

<figure><img src="image_27.png" /></figure>

10 cm

<figure><img src="image_28.png" /></figure>
A

<figure><img src="image_28.png" /></figure>

B

<figure><img src="image_29.png" /></figure>

C

<figure><img src="image_30.png" /></figure>

D

<figure><img src="image_31.png" /></figure>

E

<figure><img src="image_32.png" /></figure>

F

<figure><img src="image_33.png" /></figure>

G

<figure><img src="image_34.png" /></figure>

H

<figure><img src="image_35.png" /></figure>
<figure><img src="image_29.png" /><figcaption>B</figcaption></figure>

<figure><img src="image_30.png" /><figcaption>C</figcaption></figure>

<figure><img src="image_31.png" /><figcaption>D</figcaption></figure>

<figure><img src="image_32.png" /><figcaption>E</figcaption></figure>

<figure><img src="image_33.png" /><figcaption>F</figcaption></figure>

<figure><img src="image_34.png" /><figcaption>G</figcaption></figure>

<figure><img src="image_35.png" /><figcaption>H</figcaption></figure>

<figure><img src="image_36.png" /></figure>
-Triassic tetrapod tracks from the Ourika-Yagour basins (Morocco) are studied.

-The historical collection of Pierre-Eymard Biron is ichnotaxonomically revised.

-These exquisitely preserved trackways are studied using 3D photogrammetric technique.

-Tracks include *Apatopus lineatus*, *Isochirotherium* isp. and *Rhynchosauroides* isp.

-They suggest a Middle-Late Triassic age for the Oukaïmeden Sandstone Formation.

<figure><img src="image_36.png" /></figure>
-Triassic tetrapod tracks from the Ourika-Yagour basins (Morocco) are studied.

-The historical collection of Pierre-Eymard Biron is ichnotaxonomically revised.

-These exquisitely preserved trackways are studied using 3D photogrammetric technique.

-Tracks include *Apatopus lineatus*, *Isochirotherium* isp. and *Rhynchosauroides* isp.

-They suggests a Middle-Late Triassic age for the Oukaïmeden Sandstone Formation.

<figure><img src="image_37.png" /></figure>
Dr. Jean-David Moreau

Biogéosciences, CNRS UMR 6282

Université de Bourgogne

6 boulevard Gabriel

21000 Dijon, France

E-mail: jean.david.moreau@gmail.com

Phone: +33 (0)6 80 91 11 94

To Editor-in-Chief of *Journal of African Earth Sciences*

Dear Editor-in-Chief,

**Declaration of interests**

[x] The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

[ ] The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:

<figure><img src="image_37.png" /></figure>

Yours sincerely,

Dr. Jean-David Moreau
for the authors
Dr. Jean-David Moreau

Biogéosciences, CNRS UMR 6282

Université de Bourgogne

6 boulevard Gabriel

21000 Dijon, France

E-mail: jean.david.moreau@gmail.com

Phone: +33 (0)6 80 91 11 94

To Editor-in-Chief of *Journal of African Earth Sciences*

Dear Editor-in-Chief,

**Declaration of interests**

[x] The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

[ ] The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:

<figure><img src="image_38.png" /></figure>

Yours sincerely,

Dr. Jean-David Moreau
for the authors