Buhakia sp.

Morales, Jorge & Pickford, Martin, 2017, New Hyaenodonts (Ferae, Mammalia) From The Early Miocene Of Napak (Uganda), Koru (Kenya) And Grillental (Namibia), Fossil Imprint 73 (3 - 4), pp. 332-359 : 337-339

Buhakia sp. II

Pl. 1

L o c a l i t y. Grillental VI, Sperrgebiet ( Namibia).

A g e. Early Miocene.

M a t e r i a l. Right mandible with the p2 – m1 and the alveolus of the m2 and the anteriormost part of the alveolus of m3 (GSN GT VI 22’17). Measurements p3 (L = 9 mm, W = 4.5 mm), p4 (L = 9.15 mm, W = 5 mm), m1 (L = ca. 8.3 mm, W = ca. 4.2 mm), alveolus m2 (L = 10 mm, W = 4.8 mm) (Pl. 1).

D e s c r i p t i o n. GT VI 22’17 is a right mandible with the p2 – m1 and the alveolus of the m2 and the anteriormost part of the alveolus of m3. The front of the p2 and the lingual side of the m1 are broken. The talonid of the m1 is relatively short but it would have been broad, with a strong, tall hypoconid. The p4 is quite a bit bigger than the m1 with a well-developed, tall main cusp. The anterior and posterior cristids are almost vertical and are well-marked, especially the anterior one. There is no anterior cuspid. The talonid is short but relatively broad, and the hypoconid is strong and occupies the buccal half of the talonid, and a low crest forms the lingual border. A moderate cingulum is irregularly developed around the premolar, more marked on the anterior part of the tooth. The p3 is almost as large as the p4 but is lower with less vertical cristids. Like the p4 it has no anterior cuspid and the talonid is short, almost reduced to a posterior cingulum. The p2 has lost the anterior extremity but its basic morphology seems to be like that of the p3, and it is appreciably smaller. The two anterior premolars overlap and are oriented obliquely with respect to the p4. The mandibular ramus is deep and the symphysis very rugose, with its posterior margin at the level of the posterior root of the p3. On the buccal side of the jaw there are two foramina visible at half the height of the jaw beneath the gap between the p3 and p4. Of these the anterior one is strong and oval, the posterior one small and circular.

D i s c u s s i o n. The premolars of the Grillental VI jaw are robust and big, the two anterior premolars (p2 and p3) being only slightly smaller than the p4. The p4 is quite peculiar because of its tall main cusp with almost vertical, concave anterior cristid, and the absence of a paraconid. In effect, it is quite close in morphology to the p4 of Dissopsalis carnifex ( Barry 1988: fig. 2) and Dissopsalis pyroclasticus ( Savage 1965: pl. 3), even though the tooth is smaller than in these two species. In contrast if we attribute the p2 or p3 to D. carnifex (GSP 16036; Barry 1988: fig. 3) the differences from the Grillental specimen would be important. Unfortunately, in D. pyroclasticus the anterior premolars are not preserved although the alveoli suggest that they would have been large relative to the p4. It is possible that the p3 attributed to Dissopsalis carnifex mentioned above could be a P3 as it is morphologically close to the P 3 in the maxilla from Karungu, here identified as Buhakia sp. , sharing the presence of a weakly developed posterior cuspid, and above all a characteristic postero-buccal cingulum or basal swelling.

Some information can be obtained from Anasinopa leakeyi ( Savage 1965) in which the p4 possesses a structure similar to that described in Dissopsalis , although it differs from it by the lower height of the main cusp and the less vertical anterior cristid, as well as the greater development of the talonid. The p2 and p3 of D. pyroclasticus have a more usual morphology similar to that in the Grillental VI specimen, even though, at least in the p3 the main cusp is lower than in the Namibian form. In conclusion, the mandible from Grillental VI has several features more specialised than in Anasinopa leakeyi , a characteristic of the tribe Dissopsalini , as we point out in this paper. The dimensions of the Grillental VI specimen are smaller than Dissopsalis or Leakitherium hiwegi , and could correspond closely to Buhakia ( Morales et al. 2003, Morlo et al. 2007). The alveoli of the m 2 in GT VI 22’17 measure about 11 mm, which suggests that the tooth would have been close in dimensions to the m2 of B. moghraensis or B. hyaenoides . However, in this genus the lower premolars are unknown, and as mentioned previously, they are poorly represented in the larger genus Dissopsalis . But, we can have a reasonable idea about the characters of the premolars in this group that we call Dissopsalini which are remarkably divergent from those of the very bunodont genus Teratodon , approaching the hyaenid pattern, tall and robust premolars. This morphological pattern is clearly recognisable in the mandible from Grillental VI, from which we deduce that its inclusion in Dissopsalini is the most plausible hypothesis. In contrast, it differs in size from the species of Dissopsalis and Leakitherium , and is closer to species of Buhakia , which is for the moment, the only clear representative of this size in this tribe. For these reasons, and in the hope of finding new material in the Early Miocene sites of the Sperrgebiet, Namibia, we prefer to classify this fossil as Buhakia sp. , following the same reasoning that we used for the controversial maxilla from Karungu. Nevertheless, some doubt remains concerning the specific identification of the two fossils.