# 3D models related to the publication: Dental morphology evolution in early peratheriines, including a new morphologically cryptic species and findings on the largest early Eocene European metatherian

Killian Gernelle, Marc Godinot, Bernard Marandat, Dominique Téodori, Sandrine Ladevèze, Rodolphe Tabuce

► To cite this version:

Killian Gernelle, Marc Godinot, Bernard Marandat, Dominique Téodori, Sandrine Ladevèze, et al. 3D models related to the publication: Dental morphology evolution in early peratheriines, including a new morphologically cryptic species and findings on the largest early Eocene European metatherian. MorphoMuseum, 2025, pp.e255. 10.18563/journal.m3.255. hal-04867658

HAL Id: hal-04867658

https://hal.science/hal-04867658v1

Submitted on 7 Feb 2025

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
# 3D models related to the publication: Dental morphology evolution in early peratheriines, including a new morphologically cryptic species and findings on the largest early Eocene European metatherian.

Killian Gernelle¹*, Marc Godinot², Bernard Marandat¹, Dominique Téodori³, Sandrine Ladevèze⁴†, Rodolphe Tabuce¹†

¹Institut des Sciences de l'Évolution de Montpellier (ISEM, UMR 5554), Univ Montpellier, CNRS, IRD, c.c. 064, Place Eugène Bataillon, F-34095 Montpellier Cedex 05, France

École Pratique des Hautes Etudes, PSL, UMR 7207, CR2P, 8 rue Buffon, F75005, Paris, France

³8 impasse de San Marino, 31140 Pechbonnieu, Haute-Garonne, France

⁴Centre de Recherche en Paléontologie - Paris (CR2P, UMR 7207), Sorbonne Université, Muséum National d'Histoire Naturelle, CNRS, 8 rue Buffon, F-75005, Paris, France

*Corresponding author: killian.gernelle@umontpellier.fr; †Co-senior authors

**Abstract**

This contribution contains the three-dimensional models of the most informative fossil material attributed to both *Peratherium musivum* Gernelle, 2024, and *Peratherium maximum* (Crochet, 1979), respectively from early and middle early Eocene French localities. These specimens, which document the emergence of the relatively large peratheriines, were analyzed and discussed in: Gernelle et al. (2024), Dental morphology evolution in early peratheriines, including a new morphologically cryptic species and findings on the largest early Eocene European metatherian. https://doi.org/10.1080/08912963.2024.2403602

**Keywords:** France, Herpetotheriidae, molars, systematics, Ypresian

Submitted: 26/11/2024, published online: 06/01/2025. https://doi.org/10.18563/journal.m3.255

## INTRODUCTION

The subfamily Peratheriinae includes all Cenozoic European her-
petotheriid metatherians known to date (Ladevèze et al., 2020;
*Peratherium* and *Amphiperatherium* genera), which are charac-
terized by the conservative morphology of their tribosphenic mo-
lars. Most of their intrasubfamilial relationships are unclear so
far (Ladevèze et al., 2012; Gernelle et al., 2024b). *Peratherium*
*musivum* Gernelle, 2024 is currently the second oldest peratheri-
ine species. It was approximately two times larger than the
earliest species of this subfamily, spanned part of the time in-
terval between the MP7 and MP8+9 reference level and shares
morphological characters with the largest early Eocene metathe-
rian, *Peratherium maximum* (Crochet, 1979) (Gernelle et al.,
2024b). We present here the 3D digital models of six key spec-
imens of *Pt. musivum* and *Pt. maximum*, from three French
fossiliferous localities (Table 1). *Peratherium musivum* is best
documented in the Southern France Rians fauna, by four isolated
molars (Fig. 1A-H, L) representing two successive upper (Fig.
1A-D; M1-M2) and two successive lower (Fig. 1E-H; m1-m2)
molar loci (Gernelle et al., 2024b). The Rians specimens were
first allocated to two *Amphiperatherium* taxa (Godinot, 1981).
The M3 holotype of *Pt. musivum* (Fig. 1I-K), first attributed
to an indeterminate *Peratherium* species by Crochet (1980), is
from the Northern France locality of Soissons, thereby showing
that *Pt. musivum* was likely present somewhat simultaneously
in Northwestern and Southwestern European faunas, alongside
other contemporaneous European metatherian species (Gernelle
et al., 2024a, 2024b). During molar occlusion, the protocone

of upper molars contacts the talonid basin of lower molars at
the termination of the power stroke (Fig. 1L; Crompton and
Hiiemae, 1970). Early peratheriine species notably differ from
one another in molar features concerning the relative size of
the protocone – talonid basin functional complex, which is rela-
tively larger in *Pt. maximum* (Gernelle et al., 2024b: tables 5-6).
The peratheriine hemi-mandible from the middle early Eocene
fauna (~MP8+9) of La Borie (UM-BRI-17; Fig. 2), found and
prepared by one of us (DT), documents the first known occur-
rence of *Pt. maximum* in Southwestern Europe, and is the single
known specimen of this species with associated teeth. The rela-
tively large size of the posterior alveolus of the m2, in addition
to the elongate shape of lower molar alveoli (Fig. 2B), are in-
formative characters regarding the generic systematics of early
peratheriines (Gernelle et al., 2024b: table 4). The peratheri-
ine specimens are permanently housed in the collections of the
Muséum National d'Histoire Naturelle (MNHN), for those from
Soissons and Rians, and of the Université de Montpellier (UM),
for the hemi-mandible from La Borie (Table 1).

## METHODS

The six peratheriine specimens were scanned by one of us
(KG) using a µ-CT-scanning station EasyTom 150/Rx Solu-
tions (Montpellier RIO Imaging [MRI], ISEM, Montpellier,
France), with a resolution between 8 and 9 µm, except for the
M1 MNHN.F.RI296 (Fig. 1C-D), scanned with a resolution
of 6.6 µm. The 3D surfaces were extracted semi-automatically
from the five isolated molars of *Pt. musivum* (Fig. 1) using
<table><caption>**Table 1.** List of 3D models of *Peratherium musivum* specimens from Soissons (SN) and Rians (RI), and of *Peratherium maximum* from La Borie (BRI). Collections: Muséum National d'Histoire Naturelle, Paris (MNHN) for Soissons and Rians specimens; Université de Montpellier, France (UM) for the specimen from La Borie.</caption><thead><tr><th>Inv nr.</th><th>Taxon</th><th>Description</th><th>Collection</th></tr></thead><tbody><tr><td>MNHN.F.SN122</td><td>Peratherium musivum</td><td>right M3</td><td>MNHN, Paris</td></tr><tr><td>MNHN.F.RI220</td><td>Peratherium musivum</td><td>left M2 (partial)</td><td>MNHN, Paris</td></tr><tr><td>MNHN.F.RI296</td><td>Peratherium musivum</td><td>right M1 (partial)</td><td>MNHN, Paris</td></tr><tr><td>MNHN.F.RI368</td><td>Peratherium musivum</td><td>right m2</td><td>MNHN, Paris</td></tr><tr><td>MNHN.F.RI385</td><td>Peratherium musivum</td><td>left m1</td><td>MNHN, Paris</td></tr><tr><td>UM-BRI-17</td><td>Peratherium maximum</td><td>right hemi-mandible with p1-p3, m1-m3 alveoli, and m4</td><td>ISEM, Montpellier</td></tr></tbody></table>

the segmentation threshold selection tool of Avizo® 9.3. The M2 MNHN.F.RI220 (Fig. 1A-B) and the m2 MNHN.F.RI368 (Fig. 1E-F) have been oriented, and their protocone and talonid basin have been put in occlusion (Fig. 1L) using the MorphoDig open-source 3D freeware (Lebrun, 2018). Regarding the hemi-mandible UM-BRI-17 (Fig. 2), a pre-segmentation of the cheek teeth and dentary of one slice every 5-10 slices was performed, employing the lasso, magic wand and blow selection tools of Avizo® 9.3. The smart interpolation tool of the online platform Biomedisa (Lösel et al., 2020) was used to complete the segmentation. The 3D surface models, visualized with Avizo® 9.3, are provided in .ply format and can therefore be opened with a wide range of freeware (e.g., MorphoDig).

## ACKNOWLEDGEMENTS

We acknowledge Guillaume Billet (MNHN) for the loan of specimens from the MNHN mammals' collection, under his care. We are also thankful to Vincent N. Pernègre (MNHN), who managed the allocation of the MNHN specimen number of the holotype of *Peratherium musivum*. Three-dimensional data acquisition was performed using the micro-computed tomography (μ-CT) facilities of the MRI platform member of the national infrastructure France-BioImaging supported by the French National Research Agency (ANR-10-INBS-04, 'Investments for the future'), the labex CEMEB (ANR-10-LABX-0004) and NU-MEV (ANR-10-LABX-0020). This research was financially supported by a PhD thesis funding from the French Ministry of Higher Education, Research, and Innovation, and in part by the ANR project EDENs (ANR-20-CE02-0007). This is ISEM publication n° 2024-x.

## BIBLIOGRAPHY

* Crochet, J.-Y. 1980. Les marsupiaux du Tertiaire d'Europe. Paris: Editions Foundation Singer-Polignac. https://doi.org/10.1163/9789004630802

* Crompton, A.W., Hiiemae, K. 1970. Molar occlusion and mandibular movements during occlusion in the American opossum, *Didelphis marsupialis* L. Zoological Journal of the Linnean Society 49, 21-47. https://doi.org/10.1111/j.1096-3642.1970.tb00728.x

* Gernelle, K., Billet, G., Gheerbrant, E., Godinot, M., Marandat, B., Ladevèze, S., Tabuce, R. 2024. Taxonomy and evolutionary history of peradectids (Metatheria): new data from the early Eocene of France. Journal of Mammalian Evolution 31, 31. https://doi.org/10.1007/s10914-024-09724-5

* Gernelle, K., Godinot, M., Marandat, B., Téodori, D., Ladevèze, S., Tabuce, R. 2024b. Dental morphology evolution in early peratheriines, including a new morphologically cryptic species and findings on the largest early Eocene European metatherian. Historical Biology. https://doi.org/10.1080/08912963.2024.2403602

* Godinot, M. 1981. Les mammifères de Rians (Eocène inférieur, Provence). Palaeovertebrata 10, 43-126.

* Ladevèze, S., Selva, C., Muizon, C. de. 2020. What are "opossum-like" fossils? The phylogeny of herpetotheriid and peradectid metatherians, based on new features from the petrosal anatomy. Journal of Systematic Palaeontology 18, 1463-1479. https://doi.org/10.1080/14772019.2020.1772387

* Ladevèze S, Smith R, Smith T. 2012. Reassessment of the morphology and taxonomic status of the earliest herpetotheriid marsupials of Europe. Journal of Mammalian Evolution 19, 249-261. https://doi.org/10.1007/s10914-012-9195-0

* Lebrun, R. 2018. MorphoDig, an open-source 3D freeware dedicated to biology. 5th International Paleontological Congress (IPC5). Available at https://morphomuseum.com/downloadMorphodig

* Lösel, P. D., Kamp, T. van de, Jayme, A., Ershov, A., Faragó, T., Pichler, O., Tan Jerome, N., Aadepu, N., Bremer, S., Chilin-garyan, SA. et al. 2020. Introducing Biomedisa as an open-source online platform for biomedical image segmentation. Nature Communications 11, 5577. https://doi.org/10.1038/s41467-020-19303-w
<figure><img src="image_2.png" /><figcaption>**Figure 1.** Three-dimensional models of isolated upper and lower molars of *Peratherium musivum* from Rians in Southern France (A-H, L) and Soissons in Northern France (I-K), both in the time interval between MP7 and MP8+9 reference levels. **A-B**, MNHN.F.RI220, partial left M2 in reverse labial (A) and occlusal (B) views. **C-D**, MNHN.F.RI296, partial right M1 in labial (C) and occlusal (D) views. **E-F**, MNHN.F.RI368, right m2 in occlusal (E) and lingual (F) views. **G-H**, MNHN.F.RI385, left m1 in reverse occlusal (G) and lingual (H) views. **I-K**, MNHN.F.SN122, holotype, right M3 in occlusal (I), labial (J) and mesial (K) views. **L**, M2 MNHN.F.RI220 and m2 MNHN.F.RI368 with occluding protocone and talonid basin in distolingual view (reversed for MNHN.F.RI220). The scale bar equals 1 mm.</figcaption></figure>
<figure><img src="image_3.png" /><figcaption>**Figure 2.** Three-dimensional model of the right hemi-mandible UM-BRI-17 with p1-p3, m1-m3 alveoli, and m4, of *Peratherium maximum* from La Borie (Lauragais, Southern France; ~MP8+9). **A**, Occlusal view. **B**, Occusal view with a close-up on m1 to m4 alveoli (with m4 removed). **C**, Lateral (labial) view. **D**, Medial (lingual) view. Scale bars equal 1 mm (B) and 5 mm (A, C-D).</figcaption></figure>