Mylodontidae

Carrillo-Briceno, Jorge Domingo, Ruiz-Ramoni, Damian, Sanchez, Rodolfo, Jaimes, Arturo, Chavez-Aponte, Edwin, Prevosti, Francisco Juan, Segura, Valentina, Carlini, Alfredo Armando, Garbe, Lisa, Tombret, Olivier, Zazzo, Antoine & Sanchez-Villagra, Marcelo Ricardo, 2024, Cauca: megafaunal and felid fossils (Mammalia) from a Pleistocene site in northwest Venezuela, Fossil Record 27 (1), pp. 187-207 : 187

cf. Mylodontidae

Fig. 5

Referred material.

The right radius (AMU-CURS-1363) collected in Cauca “B” (Fig. 4B ).

Descriptions.

The AMU-CURS-1363 radius is incomplete in its distal part and has a Tl of 430 mm (Fig. 5H1, H2 ). This specimen differs in dimensions and morphology with reference to the left radius of cf. Eremotherium laurillardi (AMU-CURS-1268d; Fig. 5C1-C3 ) found in the same excavation. AMU-CURS-1363 is proportionally thicker and shorter compared to Megatheriidae and Megalonichydae (e.g. McAfee (2007)), being narrow at the proximal end and laterally expanded at the distal end, which is fragmented and deteriorated. The proximal articular head is concave, narrow, and semicircular with a maximum diameter of 40 mm. The axes are relatively straight, and a prominent laterally expanded pronator ridge is not observed, as occurs in Scelidotherinae and some Lestodontinae . These characteristics lead us to consider AMU-CURS-1363 as belonging likely to a mylodontid ( Mylodontinae ) indet.

Remarks.

The incompleteness and state of preservation of AMU-CURS-1363 does not allow for a more precise taxonomic determination. Mylodontid remains reported for the Late Pleistocene of Falcón State come from the Muaco and Taima-Taima sites and some of these have been referred to as Glossotherium tropicorum Hoffstetter, 1952, by Bocquentin-Villanueva (1979), Aguilera (2006) and Carrillo-Briceño (2015); although De Iuliis et al. (2017) noted that those specimens from Falcón appear to be distinct from the G. tropicorum material known from Ecuador and Peru. A taxonomic re-evaluation of the Glossotherium materials found in Falcón, as well as in other regions of Venezuela ( Carrillo-Briceño 2015; Chávez-Aponte 2022), would be relevant for new clues about the stratigraphic range and geographic distribution of the three valid species of Glossotherium recognised for the Pleistocene of South America (see Cartelle et al. (2019)).

Cingulata Illiger, 1811

† Glyptodontidae Gray, 1869

Figures

Figure 4. Excavations at the Cauca site. Cauca " A " (A), Cauca " B " (B), and Cauca " E " (C), showing the defence of Notiomastodon platensis (AMU-CURS- 1359) in situ. Mandible of N. platensis in plaster jacket in Cauca " A " (D). Cauca " D " with remains (tibia and ribs) of cf. Eremotherium laurillardi (E).

Figure 5. Megatheres (A 1 - G) and mylodontids (H 1, H 2) from the Cauca site. A 1 - A 4. Skull of cf. Eremotherium laurillardi (AMU-CURS- 1268 a) in right lateral, ventral, posterior and anteroventral view; B 1, B 2. Right hemi-mandible (AMU-CURS- 1268 b) in right lateral view; C 1 - C 3. Right radius (AMU-CURS- 1268 d) in proximal, dorsal and distal view; D 1, D 2. Right clavicle (AMU-CURS- 1268 c); E 1, E 2. Thoracic vertebra (AMU-CURS- 1268 j) in anterior and left lateral view; F. Thoracic or lumbar vertebral centrum (AMU-CURS- 1268 k) in anterior view; G. Left IV metatarsal (AMU-CURS- 1268 g); H 1, H 2. cf. Mylodontidae, proximal and dorsal right radius (AMU-CURS- 1363). Abbreviations: (alv.) alveolus, (fm) foramen magnum, (mf) lower molariform, (Mf) upper molariform, (oc) occipital condyle.