Neocavia lozanoi Kraglievich, 1932

Madozzo-Jaén, M. Carolina, Pérez, M. Encarnación, Montalvo, Claudia I. & Tomassini, Rodrigo L., 2018, Systematic review of Neocavia from the Neogene of Argentina: Phylogenetic and evolutionary implications, Acta Palaeontologica Polonica 63 (2), pp. 241-260 : 244-250

publication ID	https://doi.org/ 10.4202/app.00464.2018
persistent identifier	https://treatment.plazi.org/id/6127922B-FFF0-FF84-F550-3214FD5A8E84
treatment provided by	Felipe
scientific name	Neocavia lozanoi Kraglievich, 1932
status

Treatment

Figs. 3 View Fig , 4A View Fig , 5A, B, F.

Holotype: MACN-Pv 8400 , skull with left P4–M3 and right P4–M2, right mandibular fragment with incisor, p4–m2 and m3 broken ( Figs. 3 View Fig , 4A View Fig , 5B).

Type locality: Andalhuala locality, Santa María Valley, Catamarca Province, Argentina.

Type horizon: “Araucanense” (late Miocene–early Pliocene).

Material.— PVL 7057 View Materials , maxillary fragment with left and right P4–M2 ( Figs. 3B View Fig , 5A) from Andalhuala Formation (late Miocene–early Pliocene) of Encalilla locality, Santa María Valley, Tucumán Province, Argentina ( Fig. 1A View Fig ) ; MACN-Pv 8415 , left mandibular fragment with p4–m2 ( Figs. 3C View Fig , 5B 2) from the type locality .

Emended diagnosis. —The adults individuals of Neocavia lozanoi are characterized by a unique combination of characters: the primary internal flex is narrower than that of the N. pampeana sp. nov., and deeper than in N. depressidens ; the anteroposterior length of the anterior and posterior lobes of the lower molariforms is similar, differing from the N. pampeana sp. nov., in which the posterior lobe is smaller than the anterior lobe. The posterior border of the upper diastema is vertical, as in Microcavia australis and Dolicavia minuscula ; the tympanic bulla is larger than in M. australis , Dolicavia , G. musteloides , and Cavia aperea ; the parietal and occipital regions are strongly convex; the external auditory meatus is more ventral respect to the occlusal dental series, as in M. australis and Dolicavia .

Description.—Skull: The skull is only known from the holotype, but a maxillary fragment is also assigned herein (PVL 7057; Fig. 3A View Fig 1 –A View Fig 4 View Fig , B). The skull is poorly preserved, lacking the most anterior part of the rostrum and the zygomatic arch ( Kraglievich 1932, 1948). It is similar in size to M. australis and smaller than in Dolicavia .

In dorsal view ( Fig. 3A View Fig 1 View Fig ), the posterior portion of the nasal, the anterior portion of the frontal, a small fragment of the left parietal, and the endocast are partially conserved. The interorbital width (narrower width of the right frontal in the orbit) is narrower than the braincase, a condition that resembles that of other caviines (e.g., C. aperea , M. australis , Dolicavia ), and contrasts with the condition of Dolichotinae and Hydrochoerinae . The preserved portion of the endocast at the level of the parietals is posterodorsally convex, similar to M. australis and Dolicavia , but the parietal-occipital suture and the temporal fossa are not differentiated.

In ventral view ( Fig. 3A View Fig 2 View Fig , B 1 View Fig ), the posterior margin of the incisive foramina is wide, as in M. australis and Dolicavia . On the posterior wall of the diastema, the suture between both maxillae forms a small bulge, similar to that of M. australis and Dolicavia ; and the anterior ventral root of the zygomatic arch begins anteriorly to P4 ( Fig. 3A View Fig 2 –A View Fig 4 View Fig , B 1 View Fig ). The Pt is more dorsal than the Mx, forming a ridge in the palate, resembling M. australis and Dolicavia , and contrasting with C. aperea and G. musteloides , in which the Mx and Pt are at the same level in the palate.

The braincase is severely broken, but the basioccipital, occipital condyle, and part of the tympanic bullae are relatively partly preserved. The Bo has a small medial crest as in M. australis , C. aperea , and G. musteloides , but differs from the condition of Dolicavia in that it has a medial concavity. The Oc is elongated and anteromedially-posterolaterally oblique; the cast of the foramen magnum is preserved Fig. 3A View Fig 2 View Fig ).

In lateral view ( Fig. 3A 3 View Fig , A 4 View Fig , B 2 View Fig ), the posterior border of the upper diastema is vertically oriented, as in M. australis and Dolicavia . The length of the posterior border is shorter than in C. aperea and G. musteloides , and longer than in M. australis and Dolicavia . The maxilla has a groove for the passage of the infraorbital nerve and artery, and the rMx is dorsoventrally shorter than in other caviines (e.g., C. aperea , M. australis , Dolicavia ). At the level of the first molar, the specimen PVL 7057 has a small alveolar foramen with an oval section that is posteriorly open ( Fig. 3B View Fig 2 View Fig ).

The tympanic bullae are ovoid and strikingly prominent Fig. 3A View Fig 2 –A View Fig 4 View Fig ). The anteromedial-posterorlateral length of tympanic bullae (APB) is proportionally larger than that of the other Caviidae , and probably all Cavioidea ( Fig. 2A View Fig ; Table 1). The length of the APB is approximately 50% of the length from the length of premaxillary-maxillary suture to anterior border of foramen magnum (APL), as in Microcavia and Dolicavia , whereas in Galea these proportions are slightly smaller. In C. aperea the APB/APL proportion is even smaller, as in Kerodon and Dolichotinae . Furthermore, in the more derived Hydrochoerinae (e.g., Hydrochoerus hydrochaeris and Phugatherium novum ) this ratio is the smallest among Caviidae ( Fig. 6A; Table 1).

In lateral view, the shape of the epitympanic portion of the epitympanic of petrous seems to be anteroposteriorly shorter and more dorsoventrally developed than in M. australis , resembling C. aperea . The external auditory meatus (mae) is detected by a concavity in the center of the tympanic bulla, and is more ventral than the level of the dental series. The position of mae respect to the dental series resembles

Neocavia lozanoi 50.53

Microcavia australis 40.01

Microcavia chapalmalensis 39.91

Dolicavia minuscula 37.78

Galea musteloides 37.23

Galea spixii 37.26

Cavia aperea 28.54

Orthomyctera chapadmalense 26.32

Dolichotis patagonum 29.95

Dolichotis salinicola 31.26

Kerodon rupestris 30.55

Hydrochoerus hydrochaeris 17.25 B2 F G H I J1 J2

Fig. 5. Caviid rodent Neocavia from the Neogene of Argentina; upper (A, B 1, C–E) and lower (B 2, F–J) molariforms in occlusal views. A, B, F. Neocavia lozanoi Kraglievich, 1932 from Andalhuala Formation, late Miocene–early Pliocene, Encalilla locality, Santa María Valley, Tucumán Province (A) and “Araucanense”, Andalhuala locality, Santa María Valley, Catamarca Province (B, F). A. PVL 7057, right P4–M2; photograph (A 1) and explanatory drawing (A 2). B. MACN-Pv 8400 (reflected), right P4–M3 (B 1) and right p4–m2 (B 2). F. MACN-Pv 8415, left p4–m2. C–E, G–I. Neocavia pampeana sp. nov. from Cerro Azul Formation, late Miocene–early Pliocene, Caleufú locality, La Pampa Province. C. GHUNLPam 21351 (reflected), left P4–M3. D. GHUNLPam 21854, rigth P4–M3. E. GHUNLPam 21286, rigth DP4/P4–M3. G. GHUNLPam 19582, left p4–m2. H. GHUNLPam 19559, left p4–m3. I. GHUNLPam 21288, rigth p4–m2. J. Neocavia sp. from the lower levels of the Monte Hermoso Formation, Montehermosan Stage/Age, early Pliocene, Farola Monte Hermoso locality, Buenos Aires Province, MD-FM-17-01, left p4–m1 and posterior lobe of m2; photograph (J 1) and explanatory drawing (J 2). Scale bars 2 mm.

that of M. australis and Dolicavia , but contrasts with C. aperea and G. musteloides , in which the mae is at the same level as the dental series, or above. The circular infratympanic fenestra (fit) is anteroventral to the mae, and smaller, as in Dolicavia . The mastoid of petrous (Pmp) forms the mastoid sinus, laterally and posteriorly exposed. The Pmp has an anteroventral-posterodorsal orientation ( Fig. 3A 3 View Fig , A 4 View Fig ) and differs from other caviines, in which the Pmp seems to be more vertical (e.g., C. aperea , G. musteloides , M. australis , and Dolicavia ). The right paraoccipital process is much broken and is only preserved up to the level of the inferior border of the occipital condyle.

Dentary: The preserved mandibles ( Fig. 3A View Fig 5 –A 7, C) conserve the anterior portion of the dentary, part of the incisors, and p4–m2. The mental foramen is located anteriorly to p4 at half the dorsoventral heigt of the lateral surface of the dentary, as in other caviids. The notch for the insertion of the tendon of the nMpi is at the level of m1–m2, as in M. australis , and the horizontal crest is well-developed, forming a laterally projected shelf as in other caviids. The fossa for the insertion of the masseter medialis muscle (dorsal to the horizontal crest) is deeper than the nMpi, as in other caviines ( Fig. 3A View Fig 7 View Fig ), except for Galea , in which the nMpi is deeper than df. The lateral crest arises at the level of the anterior lobe of m2 and is straight, as in M. australis and G. musteloides ( Fig. 3A View Fig 5, C 1). The ventral margin of the dentary exhibits a conspicuous alveolar protuberance, similar to that of Dolicavia , and more developed than in M. australis . In lingual view ( Fig. 3A View Fig 6, C 2 View Fig ), the lower incisor extends up to the level of the anterior lobe of m1, and the mylohyoid crest is present, similar to Dolicavia , C. aperea , and Palaeocavia impar .

Molariforms: The molariforms are euhypsodont, double heart-shaped, with a constriction in the apex of the lobes, and with a transverse dentine crest on the middle of the occlusal surface at each lobe. The Hf/hf is funnel-shaped and has cement (Fig. 5A, B). The enamel is continuous around the entire crown, but is interrupted on the labial side in the upper molariforms, and on the lingual side in the lower molariforms, except in the h.p.i. and the H.S.E., as in other caviines. The length of the molariforms ( Tables 2, 3) increases anteroposteriorly (P4/p4 are smaller than M1/m1, M1/m1 are smaller than M2/m2, and M2 is smaller than M3–m3 are not preserved), the lower molariforms pattern is shared with Microcavia , Galea , and P. impar . The anterior and posterior lobes of the lower molariforms are approximately similar in anteroposterior length ( Fig. 6B).

Upper teeth: The anterior lobes have a rounded posterolabial extension that reaches the anterior margin of the posterior lobe ( Fig. 2B View Fig ). This characteristic differs from that of M. australis and Dolicavia , in which the projection is posteriorly pointed. The anteroposterior length of the anterior upper lobes is lesser than in the posterior lobes. The shallow H.S.E. (Fig. 5A, B 1) is similar to the condition of Dolicavia and M. australis . The M3 is the largest tooth and has an elongated posterior projection similar to that of Dolicavia .

Lower teeth: The h.p.i. seems to be deeper than in “ Neocavia depressidens ” ( Fig. 2C View Fig ; Table 3). The incisor is broken and the presence of an anterior lobe of p4 is variable (Fig. 5B 2, F): the assigned specimen ( MACN-Pv 8415 ) has an anterior projection, absent in the holotype ( MACN-Pv 8400 ). In the holotype, the anterior lobe is oblique in relation to the anteroposterior axis of the mandible, while in the assigned specimen ( MACN-Pv 8415 ) the anterior projection is well developed (Fig. 5B 2, F) .

Remarks.— The anatomic analyses here performed reveal certain discrepancies with respect to the description of Kraglievich (1932, 1948), mainly due to the poor preservation of the holotype (MACN-Pv 8400). According to the author, “los huesos nasales presentan una convexidad transversal moderada” [the nasal bones show a moderate transverse convexity] ( Kraglievich 1948: 143). This characteristic cannot be confirmed because only a small portion of the nasal is preserved in the anterior portion of the skull. Moreover, the author described “...adelante de los premolares unos amplios forámenes palatinos” [wide palatine foramens in front of the premolars] ( Kraglievich 1948: 143). Nevertheless, following Cherem and Ferigolo (2012), the foramen anterior to the premolars is the incisive foramen, which is only preserved in the posterior portion without a medial septum. In addition, Kraglievich (1948) described that the rostrum is inclined respect to the basioccipital, as in Dolicavia , but this characteristic is shared by all Caviinae .

The dentary was broken, probably after the description of Kraglievich (1932, 1948; Fig. 4A View Fig ). In this sense, the specimen has been imprecisely repaired ( Fig. 3A View Fig 5), so that the most anterior part is laterally rotated, and the posteroventral projection of the posterior end of the mandibular symphysis is not present. However, it is illustrated in a posterior paper of Kraglievich (1948). According to Kraglievich (1932, 1948), and Parodi and Kraglievich (1948), the masseteric crest in the dentary is much developed and begins at the level of m1. However, following Pérez (2010a, b), the portion at the level of m1 corresponds to the nMpi; the crest corresponds to the horizontal crest, and the portion of dentary with the masseteric crest is not preserved.

Stratigraphic and geographic range.— Late Miocene–early PlioceneofArgentina,“Araucanense”,AndalhualaFormation; Santa María Valley in Andalhuala locality, Catamarca Province and Encalilla locality, Tucumán Province.

“ Neocavia depressidens ” Parodi and Kraglievich, 1948

Fig. 4C View Fig .

Holotype: MLP 46 View Materials -V-13-53, left mandibular fragment with p4–m2 ( Fig. 4C View Fig ).

Type locality: Farola Monte Hermoso locality, Buenos Aires Province, Argentina ( Fig. 1C View Fig ).

Type horizon: Upper? levels of the Monte Hermoso Formation, early Pliocene, Monteherrmosan Stage/Age ( Parodi and Kraglievich 1948; Tomassini et al. 2013).

Diagnosis (from Parodi and Kraglievich 1948).—“Cavino pequeño con los molares constituidos por dos prismas separados externamente por un surco amplio; internamente ofrecen un surco pequeño poco insinuado colocado un poco atrás con relación al externo. El primer prisma del p4 no tiene prolongamiento anterior y es menor que el segundo; las caras externas anteriores y posteriores de los prismas son algo deprimidas en el centro; la cresta masetérica arranca en la parte más anterior del m1”. [Small caviine with molars consisting of two prisms separated externally by a broad groove; internally showing a small, slightly insinuated groove, located a little back with respect to the external one. The first lobe of p4 has no anterior extension and is smaller than the second one; the anterior and posterior external faces of the prisms are somewhat depressed in the center; the masseteric ridge starts at the most anterior part of m1] ( Parodi and Kraglievich 1948: 66–67).

Remarks.— “ Neocavia depressidens ” ( Fig. 4C View Fig ) was diagnosed, described, and figured by Parodi and Kraglievich 1948). The holotype and only known specimen is currently lost. The original drawing possibly does not accurately reflect all the diagnostic characters given by the authors, and even other characters (e.g., constriction in the apex of each lobe of molariforms) have been drawn, but were not described. Additionally, here we interpret that “por el punto de arranque de la cresta masetérica” [by the starting point of the masseteric crest] ( Parodi and Kraglievich 1948: 67) refers to the anterior border of the nMpi (sensu Pérez 2010a, b), and that “el surco ... colocado un poco atrás con relación al externo” [the groove ... located a little behind in relation to the external] ( Parodi and Kraglievich 1948: 67) refers to h.p.i. (sensu Mones 1991), which is located posteriorly to the hypoflexid, and which, in this case, would be superficial.

Due to the loss of type material, and the result of phylogenetic analysis (see Phyogenetic analysis below), we decided to use a quotation mark to name “ Neocavia depressidens ”, until corroborating the validity of this taxon.