Vetelia gandhii Esteban & Nasif, 1996

Brandoni, Diego, Barasoain, Daniel & González Ruiz, Laureano R., 2023, Late Miocene Dasypodidae Gray, 1821 (Xenarthra, Cingulata) from the Toro Negro Formation (Central Andes, Argentina): diversity and chronological and biogeographical implications, Comptes Rendus Palevol 22 (1), pp. 1-16 : 4-6

Vetelia gandhii Esteban & Nasif, 1996

( Fig. 3 A-F; Table 1)

Vetelia puncta Esteban & Nasif, 1996: 329 .

MATERIAL REFERRED. — CRILAR-Pv 116, one isolated fixed osteoderm; CRILAR-Pv 117, one fixed osteoderm associated with a fragment of an osteoderm from the right lateral border of the carapace; and CRILAR-Pv 118, an association of seven broken osteoderms interpreted as belonging to a juvenile.

GEOGRAPHIC AND STRATIGRAPHIC PROVENANCE. — Quebrada de Las Torrecillas (28°36’S, 68°14’W), La Rioja Province, Argentina ( Fig. 1). Upper levels of the lower member of the Toro Negro Formation (Messinian-Zanclean; Late Miocene-Early Pliocene).

DESCRIPTION

Fixed and lateral osteoderms. The size of fixed osteoderms is similar to that of the extant Priodontes maximus ( Kerr, 1792) .

A B C D E F

The fixed osteoderm CRILAR-Pv 116 ( Fig. 3A) is thick, wide, and has a pentagonal outline, and probably belongs to the more dorsal region of the carapace. In turn, the fixed osteoderm CRILAR-Pv 117 ( Fig. 3B) is thinner and narrower than CRILAR-Pv 116 and has a sub-rectangular in outline, so it probably occupied a more lateral position within the carapace. The whole dorsal surface of the osteoderms is full of small foramina. In lateral view, osteoderms have a constant thickness from the anterior to the posterior margin.

The ornamentation pattern of the dorsal surface is composed by a wide and slightly convex central figure, and a variable number (4-5) of minor peripheral figures restricted to the anterior half of the osteoderm. The central figure is sub-elliptical, and is delimited by a main sulcus containing several small dorsal foramina, which are more numerous in the proximal area. Towards the posterior margin of the osteoderm, this sulcus becomes progressively shallower until disappearing, so that the central figure becomes unified with the remaining dorsal surface of the osteoderm. The peripheral figures, anteriorly placed, are sub-pentagonal, and delimited by minor sulci. Contrary to the main sulcus, these sulci have no dorsal foramina and are much deeper.

In the posterior margin, there is a variable number of large piliferous foramina, posteriorly oriented and arranged into a single row. Osteoderm CRILAR-Pv 116 has just one foramen, while osteoderm CRILAR-Pv 117 has a row of three piliferous foramina. There are no foramina at the lateral margins of the fixed osteoderms. By contrast, there are two piliferous foramina in the external margin of the preserved fragment of the osteoderm from the right lateral border of the carapace ( Fig. 3C).

Juvenile osteoderms. These osteoderms (CRILAR-Pv 118; Fig. 3 D-F) are of similar shape to those of fixed osteoderms of adult individuals, but can be recognized as belonging to juvenile stage due to several features, such as a much smaller size ( Table 1); undeveloped central and peripheral figures and very punctuate dorsal and ventral surfaces. The same morphological differences have been reported for juveniles of other cingulate groups such as glyptodonts (see Luna & Krapovickas 2011; Zurita et al. 2011; Luna et al. 2018). Additionally, these osteoderms have a series of conspicuous dorsal foramina which correspond with the location of the main sulcus in osteoderms belonging to adult individuals.

REMARKS

Vetelia includes V. puncta , V. perforata Scillato-Yané, 1977 , and V. ghandii . The analyzed specimens are assigned to V. ghandii for having large and scarce piliferous foramina (1-3) at the posterior margin. In V. perforata foramina are much smaller and numerous (6-14) (see Scillato-Yané 1977, 1982; Barasoain et al. 2021). In turn, V. puncta osteoderms develop several small piliferous foramina at the posterior margin ( Ameghino 1891), several dorsal foramina in both main and minor sulci, and smaller piliferous foramina are present at the anterior and lateral margins of the osteoderm, which are absent in V. ghandii (see Esteban & Nasif 1996; Barasoain et al. 2021).