Orocavia andina Jaén & Pérez 2024, n. comb.
Year: 2024
Type: other
Abstract: Orocavia andina (Rovereto, 1914) n. comb. (Figs 3-7; Tables 1-3) Dolichotis andina Rovereto, 1914: 58, fig. 25. Orthomyctera (Orocavia) andina Kraglievich, 1932: 163. TYPE MATERIAL. — Holotype. Argentina. MACN-Pv 8350, skull with articulated atlas, complete upper dental series, and left mandibular fragment with i, p4-m3. REFERRED MATERIAL. — MACN-Pv 8300, right mandible fragment with p4-m3; MACN-Pv 8347, palatal fragment with right P4-M2 and fragment of M3 and left P4-M1; MACN-Pv 8349, left mandible fragment with p4-m2; MACN-Pv 8351, fragment of skull with complete dental series; MACN-Pv 8399, fragment of skull with complete dental series; MACN-Pv 8401, fragment of skull with complete dental series; MACN-Pv 8402, palatal fragment with complete dental series; MACN-Pv 8403, palatal fragment with left P4-M3 and right P4-M2; MACN-Pv 8404, palatal fragment with left M1-M3 and right P4-M1; MACNPv 8409, palatal fragment with left M1-M3; MACN-Pv 8411, right mandible fragment with m1-m3; MACN-Pv 8412, right mandible fragment with p4-m3; MACN-Pv 8414, left mandible fragment with p4-m3; PVL 3293, left mandible fragment with p4-m3; FMNH P 14464, fragment of skull with complete dental series; FMNH PM 1094, fragment right mandible p4-m2; FMNH P 14370, fragment of skull with complete dental series and atlas; PVL 4892, fragment of skull with complete dental series; MCH-P 90, fragment of skull with right complete dental series and left P4-M2 and anterior lobe of M3; MCH-P 91, fragment of skull with left M1 and right M1-M2; MCH-P 94, left mandible fragment with p4-m2; MCH-P 345 right mandible fragment with p4-m2; MCH-P 346 left mandible fragment with m1-m2; MCH-P 360 left mandible fragment with m1-m2; MCH-P 361 left mandible fragment with m1-m2; MCH-P 366 maxilla fragment with right P4-M2 and fragment of M3 and left P4-M1 and left mandible fragment with m1; MCH-P 367 left mandible fragment with p4. The provenance of each referred material is detailed in Appendix 9. MODIFIED DIAGNOSIS. — Caviinae diagnosed by the following unique combination of characters (apomorphies marked with an asterisk): cheek teeth euhypsodont, bilobed, and each heart-shaped; constriction in the apex of each lobe present; hypoflexus/ id funnel-shaped; dentine crest in the middle of occlusal surface in each lobe; cement in the hypoflexus/id present; *furrow opposite to hypoflexus/ids present as in Dolichotinae, differing from the other Caviinae (Galea, Cavia, Microcavia, Palaeocavia, Neocavia, Dolicavia, and Orthomyctera); enamel interrupted on the labial side in upper cheek teeth, and on the medial side in lower ones, except on the furrow opposite to hypoflexus/id; M1 shorter and M3 longer than the other cheek teeth as in O. rigens; posterior projection of M3 anteroposteriorly long, shorter than in Dolicavia; anterior projection of p4 anteriorly well-developed differing from Palaeocavia and Cavia. Lateral ridge of the infraorbital groove absent; posterior portion of diastema oblique and shorter than in Cavia aperea Erxleben, 1777 and Galea leucoblephara, differing from O. rigens, Microcavia and Dolicavia. Terraced palate shallower than in Neocavia, O. rigens, Dolicavia, and M. australis. Tympanic bullae with respect to skull length are large as Dolicavia, M. australis, and Neocavia, but smaller than in N. lozanoi. External auditory meatus more ventral respect to the occlusal dental series, as in Dolicavia, M. australis, and N. lozanoi. Notch for insertion of the tendon of the masseter medialis pars infraorbitalis muscle is deeper depth than dorsal fossa of horizontal crest. TYPE LOCALITY. — Argentina, Andalhuala locality, Catamarca Province, Santa María Valley. Late Miocene-early Pliocene (“Araucanian”). GEOGRAPHIC AND STRATIGRAPHIC PROVENANCE. — Santa María Valley, Catamarca Province: in Andalhuala and “Al sureste de ex Chiquimil”, [Southeast from ex Chiquimil] Entre Ríos localities, without precise stratigraphic data (Late Miocene-Early Pliocene, and “Araucanense”; Marshall & Patterson 1981); Entre Ríos (ex Chiquimil) locality, Andalhuala Formation, in levels XVIIIa and XVIIIb; Loma Rica locality in level XVII (Late Miocene, Marshall & Patterson 1981). Villavil-Quillay basin, Catamarca Province in Villavil locality, Chiquimil Formation, El Jarillal Member, (Late Miocene, Powell et al. 1998; Esteban et al. 2014); Western Slope of Cerro Pampa (San Fernando Sur locality), Andalhuala Formation (Late Miocene-Early Pliocene; Bonini et al. 2021). DESCRIPTION AND COMPARISON Cranium The anteroposterior length of Orocavia andina n. comb. is approximately similar to that of Orthomyctera rigens (Fig. 2), larger than in M. australis and smaller than Dolicavia (Appendices 4; 5). The APL of the rostrum in relation to APL of the skull is larger than in M. australis (approximatively 7.5% longer) and Dolicavia (approx. 4% longer). The width of the braincase is smaller than in Dolicavia (approximatively 20% less) and somewhat larger than in M. australis and Neocavia lozanoi (approximatively 10% longer) Table 1; Appendices 4; 5). Nasal. The nasals are better preserved in the holotype, but the anterior portion is missing (Fig. 4A). In dorsal view, this bone is relatively wider than in M. australis, and narrower than that of Dolicavia. The nasofrontal suture is anteriorly concave (Fig. 4 A-C) as in Dolicavia or slightly concave (Fig. 5A) as in M. australis. In lateral view, the nasal is dorsally convex in the medial portion (Fig. 6A, B; Appendices 4; 5). Premaxilla. In dorsal view (Figs 4A; 5A), the dorsal process of the premaxilla is narrow along the contact with the nasal, widening posteriorly. In lateral view, the alveoli of the upper incisors are broken in all the specimens that preserve this portion (Figs 4B, C; 6A). The premaxillary portion of the rostral masseteric fossa is shallow as in Dolicavia. The premaxillamaxilla suture in the lateral wall of the rostrum is unclear in the holotype because this region is deteriorated (Fig. 4B, C). In ventral view, the suture is located on the posterior half portion of the diastema, as in Dolicavia and M. australis. Approximately 75% of the margins of the incisive foramen are formed by the premaxilla. This foramen (Figs 4D; 5D) is similar in size and shape to those of Dolicavia, Microcavia (Appendices 4; 5). Maxilla. In lateral view, the maxillary portion of the rostral masseteric fossa is in the middle of the rostrum (Figs 4B, C; 6A), this fossa is less developed than in M. australis. At the P4 level, a lateral vacuity of the nasolacrimal duct (nasolacrimal foramen sensu Ubilla et al. 1999; maxillary lacrimal canal sensu Cherem & Ferigolo 2012) is present (Fig. 6C). This vacuity is present in Caviinae and Hydrochoerinae (e.g. Hydrochoerus), but absent in Dolichotinae (e.g. Dolichotis). In the posterior portion of the diastema, the maxilla is obliquely oriented respect to alveolar line (Figs 4B, C; 6G), and this condition differs from M. australis, Dolicavia, and N. lozanoi (see above). The lateral ridge of the infraorbital groove is absent. It differs from O. rigens, N.lozanoi, Dolicavia, and M. australis, in which it is present. The sphenopalatine foramen is between groove infraorbital and alveolar protuberances of P4 and M1 (Cherem & Ferigolo 2012; Fig. 6D, E). Dorsally to the alveolar protuberance of M2 (Fig. 6 C-E), the lacrimomaxillary fissure (sensu Cherem & Ferigolo 2012) extends posteriorly. The maxillary process of the zygomatic arch originates at the level of P4, anteriorly is elongated and dorsoventrally low (Fig. 6 A-F). In ventral view, the origin of the zygomatic arch presents a shallow notch of the tendon of the medial part of masseter muscle (Fig. 5D). This notch is an elliptical concavity with well-defined edges in O. rigens (Fig. 2D) and Dolicavia (Appendices 4; 5). The palate is triangular and terraced; the central portion is more dorsal than the alveolar border but this difference is less marked than Neocavia, O. rigens, Dolicavia, and M. australis (Figs 2D; 4D; Appendices 4; 5). Palatine. The notch for the minor palatine nerve and vessels (sensu Wible et al. 2005) is medial to the posterior projection of M3 (Fig. 5C). Some specimens (Fig. 5D, F) have preserved a palatine crest on the middle line that extends up to the M1-M2 level. The anterior apex of the mesopterygoid fossa is U-shaped and anteriorly extended up to the level of the anterior lobe of M3 (Figs 4D; 5D), as in M. australis. The anterior margin of sphenopalatine vacuity (sensu Cherem & Ferigolo 2012); is limited by palatine and medially by the presphenoid; the posterior margin is not preserved (Fig. 5C). Frontal. In dorsal view, the nasal process of the frontal (sensu Cherem & Ferigolo 2012; i.e., the anterior projection of the frontal, between the nasal and the premaxilla) is triangular-shaped and conspicuously extended anteriorly in the holotype (Fig. 4A); whereas in MACN-Pv 8351 (Fig. 5A) is not anteriorly projected. The interorbital width is similar to that of M. australis and smaller than in Dolicavia (Appendices 4; 5). The contacts with parietals are straight as M. australis, D. minuscula. Parietal. The parietal is dorsolaterally convex (Fig. 4A), as in O. rigens Dolicavia, M. australis (Appendices 4; 5), and N. lozanoi, but differs from D. patagonum which have anterior portion slightly convex (see Rovereto 1914). The temporal fossae are shallow and do not developed a sagittal crest; there is a differentiated plane area named the “interposed flat zone” by Quintana (1998) Fig. 4A), as in Dolicavia and M. australis. The specimens of Or. andina n. comb. consists of adult individuals in which the interparietal is not recognized; this condition differs from Dolicavia in which the interparietal is not fused with the parietal in adult specimens. This region is deformed in other skulls of Or. andina (e.g. MACN-Pv 8351, MACN-Pv 8401; Figs 5A; 6E). Lacrimal. In lateral view, the anterodorsal portion of the zygomatic arch of the holotype (Fig. 4C) ha
Authors: Jaén, María Carolina Madozzo, Pérez, María Encarnación
Language: English
Subfield: Paleontology
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W6930650459
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