Libycochoerus massai Arambourg, 1961

Pickford, Martin, Miller, Ellen R. & El-Barkooky, Ahmed N., 2010, Suidae and Sanitheriidae from Wadi Moghra, early Miocene, Egypt, Acta Palaeontologica Polonica 55 (1), pp. 1-11 : 7-8

Libycochoerus massai Arambourg, 1961

Fig. 5D .

Holotype: Left mandible with p2–m3, No. 1961−5−8 MNHN Paris.

Type locality and horizon: Terminal early Miocene to basal middle Miocene, Gebel Zelten, Libya.

Material.—WM DEC06−09, partial right M3 ( Fig. 5D ); CGM 30791, right talus; DPC 17744 canine and DPC 14565 canine are provisionally referred to this species.

Diagnosis.—Large kubanochoere, about 10–20% smaller than Kubanochoerus robustus ; upper molar series about 100 mm long ( Pickford 1986).

Description.—WM DEC06−09, a partial upper third molar is unworn but is missing part of the paracone and the buccal edge of the metacone ( Fig. 5D ). However, enough remains of the tooth to reveal its main characters. The protocone, metacone and hypocone are well preserved conical bunodont cusps with coarse but shallow furchen and wrinkles. The anterior and median accessory cusplets are also conical and voluminous, being about 2/3rd the height of the main cusps. The anterior accessory cusplet is located well anterior to the line joining the apices of the paracone and protocone, and it is fused to the beaded anterior cingulum. The hypocone has a cingular remnant on its antero−lingual corner, partly blocking off the transverse valley. The median accessory cusp is relatively small and low. The hypoconule is located in line with the protocone and hypocone, and it sends a descending beaded cingulum antero−buccally. This tooth is remarkably similar to material of Libycochoerus massai from Gebel Zelten (see specimens illustrated by Van der Made 1996: pl. 10: 7, 8). In terms of size, WM DEC06−09 plots out at the small end of the range of variation of L. massai from Gebel Zelten ( Fig. 7 ), but we have little hesitation in attributing this tooth to the species. Dental dimensions for the Moghra specimen are provided in Table 2 and Table S4 (see Supplementary Online Material at http://app.pan.pl/SOM/app55-Pickford_etal_SOM.pdf) provides comparative dental data from a large sample of other African and Eurasian kubanochoerines.

CGM 30791 is a right talus from a large suid the dimensions of which are close to those of LBE 505, a right talus from Gebel Zelten attributed to L. massai ( Orliac 2007: fig. 66.2). Dimensions of the Moghra and Zelten tali are provided in Table S5 (see Supplementary Online Material at http://app.pan.pl/SOM/app55-Pickford_etal_SOM.pdf).

Geographic and stratigraphic range.—Wadi Moghra, Egypt; Gebel Zelten, Libya ( Arambourg 1961, 1963), early to middle Miocene.

cf. Libycochoerus sp. sensu Drake et al. (1988)

Locality and horizon: Moruorot and Kalodirr are aged ca. 17.2 Ma, whereas Rusinga and Karungu are 17.8 Ma ( Drake et al. 1988).

Material.—DPC 8947, left mandible fragment with wind−abraded m1 to m3.

Description.—DPC 8947, a sand−blasted left mandible with part of the right symphysis preserved, contains worn and damaged m1–m3 and roots of p4 ( Fig. 6 ). The symphysis is solidly fused and very thick dorso−ventrally, its posterior extremity lying beneath about the p3, but the specimen is so damaged that little can be said about its morphology. It is possible to see however, that the junction between the two halves of the symphysis forms a raised ridge lingually, suggesting that the individual was aged when it died, a possibility supported by the heavy wear on the m3. The buccal surface of the jaw has been destroyed leaving nothing to be ob−

doi:10.4202/app.2009.0015

served concerning the position of the mental foramen or the dimensions of the canine. The sublingual fossa is large and extends anteriorly as far as the m1, forming a deep recess beneath m3. The teeth are deeply worn occlusally and on their buccal sides have suffered greatly from wind−driven sand. Lingually the teeth are better preserved, and they reveal that the median transverse valleys in the m2 and m3 were broad near the cervix, as in the genus Libycochoerus ( Pickford 1986) . The median accessory cusps extend across less than half the bucco−lingual breadth of the tooth. This is clearly visible in the m2, in which the remnant of this accessory cusplet shows an almost circular outline, markedly divergent from the bucco−lingually elongated and mesio−distally compressed outline that occurs in teeth of Nguruwe species. The ends of the median transverse valleys do not possess any tubercles or cingular remnants. Although accurate measurements are difficult to take on account of the abrasion of the specimen, DPC 8947 is clearly larger than known specimens of Kenyasus rusingensis ( Fig. 7 ), and is about the same size as Libycochoerus jeanneli and L. anchidens ( Table 3).

Discussion.—The restricted amount of morphology that is discernible in this wind−abraded fragment is not compatible with Listriodontinae or Hyotheriinae , but recalls Kubanochoerinae . The dimensions of DPC 8947 are comparable with both Libycochoerus anchidens and Libycochoerus jeanneli , and both species are known from East Africa in deposits dated to between ca. 17.8 and 17.2 Ma ( Pickford 1986, 2007). Miocene suid taxa tend to be extremely widespread, so the presence of one or the other of these species at Moghra would not be surprising. The species Nguruwe kijivium is equally widespread, being reported from Namibia, East Africa and Moghra. The possible presence of Libycochoerus anchidens or Libycochoerus jeanneli at Moghra would provide additional support for the view that the stratigraphic succession in the region includes deposits spanning the end of the early Miocene.

Geographic and stratigraphic range.— Libycochoerus jeanneli is known from Moruorot (type locality) and Kalodirr, Kenya ( Arambourg 1933; Pickford 1986; Orliac 2007): Libycochoerus anchidens is known from Rusinga (type locality) and Karungu, Kenya ( Pickford 1986; Van der Made 1996), early Miocene.

Figures

Fig. 5. Kubanochoerin suids from early Miocene of Wadi Moghra, Egypt. A–C. Nguruwe kijivium (Wilkinson, 1976). A. Right mandible with m2–3 (DPC 4385) in lingual (A1), occlusal (A2), and buccal (A3) views. B. Right m/3 (DPC 14564) in occlusal view. C. Left m3 (WM Dec 06−10) in occlusal view. D. Libycochoerus massai Arambourg, 1961 partial, right M3 (WM Dec 09) in occlusal view.

Fig. 7. Length versus breadth scatter plots of suid molars from early Miocene of Wadi Moghra (black diamond) compared with early and middle Miocene suids from other localities in Africa. Abbreviations: A, Libycochoerus anchidens (Van der Made, 1996); B, Megalochoerus marymuunguae (Van der Made, 1996); J, Libycochoerus jeanneli (Arambourg, 1933); K, Nguruwe kijivium (Wilkinson, 1976); M, Libycochoerus massai Arambourg, 1961; N, Nguruwe namibensis (Pickford, 1986); Q, Kenyasus namaquensis Pickford and Senut, 1997; R, Kenyasus rusingensis Pickford, 1986; Z, Megalochoerus khinzikebirus (Wilkinson, 1976).

Fig. 6. Kubanochoerin suid cf. Libycochoerus sp. (size of Libycochoerus jeanneli and Libycochoerus anchidens) sensu Drake et al. (1988) from early Miocene of Wadi Moghra, Egypt, (DPC 8947), left mandible fragment with wind−abraded m1–m3 in buccal (A), occlusal (B), and lingual (C) views.