DOI: 10.5061/dryad.pk0p2ngx8
title: 3D meshes of H1 and H6 footprints at PK23 track site, Northern Chile

description: We report new ichnites corresponding to a trackway composed of three
 tetradactyl pedal footprints and plant remains near Southeastern
 Guatacondo, Tarapacá Region, within the transition of Majala and
 Chacarilla Formations (Late Jurassic-Early Cretaceous). The fossils were
 found in the context of a Copper Mining road construction at the PK23
 site, Quebrada Blanca Phase 2 project, by the Teck Mining Company Quebrada
 Blanca S.A. We performed stratigraphical, paleobotanical, and
 paleoichnological studies, along with the footprint characterization and
 comparisons by Principal Component Analysis, and Discriminant Analysis of
 I-II, II-III and III-IV interdigital angles, using a large tetradactyl
 footprint morphological database of potential producers (dinosaurs,
 crocodiles, lepidosaurs, and pterosaurs). Additionally, we performed 3D
 pedal computer modeling kinematic analysis of the Chilesaurus
 diegosuarezi’s 3D tetradactyl foot under two different sedimentary
 conditions (i.e. hard soil with superficial impression, and soft sediment
 with a penetrative impression), to test it as a potential trackmaker. The
 stratigraphic section reveals an association of siliciclastic facies,
 formed by the intercalation of fine-grained sandstones and wackes, with
 ripple marks, cross and horizontal lamination, evidencing intermittent
 moderate to low sedimentation energy. Among the plant material, several
 organs of the family Cheirolepidiaceae were identified such as, leaves and
 leafy branches of Brachyphyllum type, Classostrobus pollen cone,
 ovuliferous scales, and wood fragments related to Cupressinoxylon. The
 monodominance of Cheirolepidiaceae among the preserved macroflora allows
 inferring the characteristics of the environment in which the plants
 lived, highlighting halophytic, and temporarily arid conditions. Evidence
 as a whole, permits to interpret the depositional environment as an arid
 deltaic-littoral plain, temporarily covered with an ephemeral water layer
 associated with a stunted woody vegetation, in which terrestrial
 vertebrates walked by. Despite the low predictive power of the
 multivariate analysis, due to the various sources of morphological
 variability inherent to footprint formation, the PK23 footprints seem to
 better correspond to Dinosauria or Avialae as the most likely producers,
 rather than to Lepidosauria or Crocodylia, discarding the dinosaur
 Chilesaurus due to very low interdigital mediolateral rotation
 capabilities.
description: This investigation was carried out in transitional strata between
 the Majala and the Chacarilla formations outcropping eight kilometers to
 the southeast of Guatacondo, Tarapacá Región in northern Chile, within the
 Quebrada Blanca Phase 2 project owned by Teck Mining Company Quebrada
 Blanca S.A (Fig. 1). Unfortunately, it is no longer possible to see the
 footprints in-situ, since the original site subsequently collapsed, so.
 However, prior to this event, we carried out three field trips in which it
 was possible to scan some sectors of the surface in 3D (Available from
 DRYAD WEBSITE), along with a collection of casts and rock
 samples.  Six biogenic structures were initially
 recognized, in which three correspond to a single trackway. Two of them
 (H1-H6, virtual meshes available at the DRYAD WEBSITE), show good
 preservation of anatomical details. These footprints were scanned using
 Go!Scan20 for the generation of 3D models with the software Vxelements,
 Creaform<sup>MR</sup>. Additionally, rubber and plaster molds
 were made following Reuil and Muzzopappa (2019) protocols.
 The collected material used to develop this study is stored and
 housed at the Municipal Museum of Pica, Tarapacá Region, Chile. Thus far,
 only field numbers have been assigned to the material.
 All the paleontological interventions at PK23 fossiliferous
 outcrop were carried out under the voluntary commitments detailed in the
 Environmental Classification Ordinance (Resolución de Calificación
 Ambiental “RCA” in spanish) number 074/2018 CV-17, reviewed and mandated
 by The Council of National Monuments in Chile.
description: # 3D meshes of H1 and H6 footprints at PK23 track site, Northern Chile
 [https://doi.org/10.5061/dryad.pk0p2ngx8](https://doi.org/10.5061/dryad.pk0p2ngx8) Data contains two untextured meshes for H1 and H6 footprints in obj format. Files have been set for easy printing, including a straight base which facilitates exhibition on a table. The original dimensions have not been modified. ## Description of the data and file structure Data could be used for education and/or for comparison with other footprints.