Catonyx tarijensis ( Gervais & Ameghino, 1880 )

Verger, Kévin Le, 2023, Xenarthrans of the collection of Santiago Roth from the Pampean Region of Argentina (Pleistocene), in Zurich, Switzerland, Swiss Journal of Palaeontology (3) 142 (1), pp. 1-39 : 27

Catonyx tarijensis ( Gervais & Ameghino, 1880) .

Referred material: Cranium: PIMUZ A/ V 511; cranium: PIMUZ A/ V 512 ( Fig. 10 ); mandible fragment with three teeth: PIMUZ A/ V 516; Mf1: PIMUZ A/ V 524; Mf1: PIMUZ A/ V 525; mandible fragment: PIMUZ A/ V 4129.

Comment: Tis generic reassignation is largely based on the study of PIMUZ A/V 512, an exceptionally well-preserved cranium. PIMUZ A/V 512 exhibits a mediolaterally wider nasal cavity than in Scelidotherium , a convex cranial roof in lateral view, a relatively more robust dentition than Scelidotherium , a mediolaterally broad snout, and a mesiodistally elongated caniniform. Tese morphological traits suggest reassignment to the genus Catonyx (following Miño-Boilini et al., 2014) rather than confirming the initial assignment to Scelidotherium (see Additional file 1: Table S1). For a more specific determination, the dentition is the main diagnostic element (Corona et al., 2013; Miño-Boilini, 2016). PIMUZ A/V 512 shows a weak trilobulation of Mf1 and Mf2 without a prominent groove, supporting an assignment to Ca. tarijensis rather than Ca. cuvieri (Corona et al., 2013; Miño-Boilini, 2016). Te occlusal shape pattern of PIMUZ A/V 512 matches that proposed by Corona et al. (2013) for Ca. tarijensis (see Fig. 5C —MMP n/n) and it is here assigned to this species. PIMUZ A/V 511 has a cranium similar to PIMUZ A/V 512 and this is the basis for the taxonomic interpretation; although teeth are not preserved. PIMUZ A/V 516 shows a less trilobate shape in occlusal view from mf2 to mf4, while mf4 has a triangular shape as reported for Ca. tarijensis species by Corona et al. (2013). PIMUZ A/V 524, PIMUZ A/V 525, and PIMUZ A/V 4129 were all originally assigned to Scelidotherium patrium Ameghino, 1888 , a species that is now invalid and considered juveniles of Ca. tarijensis ( Miño-Boilini et al., 2019) . Te presence of Catonyx in the Roth collection at PIMUZ brings a new complexity regarding the diversity of scelidotheres, as Ca. tarijensis is considered a species with a high ecological tolerance to different environments and altitudes ( Miño-Boilini & Quiñones, 2020). A more important fact is the high preservation quality of two subcomplete crania in the collection although the cranial and endocranial anatomy of this species was already well described (Boscaini et al., 2020a; Miño-Boilini, 2016).

Figures

Fig. 10 Plate of crania belonging to the Pilosa from the Roth collection at PIMUZ. Each‘subfamily’ presents cranial remains among which the most complete belong to the Mylodontinae, the Scelidotheriinae and the Nothrotheriinae. Scale bar= 10 cm

Fig. 5 Plate of the most complete postcranial remains of the forelimb from the Roth collection at PIMUZ and a ground sloth scapula. Among the Cingulata, the best represented clades are large-sized armadillos (Eutatini, Pampatheriinae) and glyptodonts. In the ground sloths, only the mylodonts are not represented here. Scale bar= 1 cm