Nguruwe kijivium ( Wilkinson, 1976 )
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publication ID |
https://doi.org/ 10.4202/app.2009.0015 |
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persistent identifier |
https://treatment.plazi.org/id/03AC87C6-FFD7-FFF9-FF86-FA84124DF9D9 |
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treatment provided by |
Felipe |
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scientific name |
Nguruwe kijivium ( Wilkinson, 1976 ) |
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Nguruwe kijivium ( Wilkinson, 1976)
Fig. 5A–C View Fig .
Holotype: NAP I’64, left maxilla fragment with M1–3, figured in Wilkinson 1976: pl. 2: g; Pickford 1986: fig. 6.
Type locality and horizon: Early Miocene, Napak I, Uganda.
Material.—WM 97−715, left m3; WM DEC06−10, worn left m3 ( Fig. 5C View Fig ); DPC 4385, right mandible fragment with m2–3 ( Fig. 5A View Fig ); DPC 14564, right m3 ( Fig. 5B View Fig ).
Diagnosis.—A small genus of Kubanochoerinae in which I1 is labiolingually compressed, not meeting interproximally; P4 with two main cusps and complete cingulum; molars with thick enamel, inflated main cusps, closed lingual notches; simple talon/id in upper and lower third molars; occlusal outline of m3 symmetrical; p3 with wide distal lingual cingular cusp or platform; p4 with metaconid almost completely suppressed; dm4 buccolingually inflated; lower canine scrofic; upper canine with dorsal cement cover ( Pickford 1986).
Description.—DPC 4385, a right mandible fragment, retains m2 and m 3 in medium wear ( Fig. 5A View Fig ). The m2 has four main cusps arranged in two lophids and there are small anterior, median and posterior cusplets in the center line of the crown. The median accessory cusplet is antero−posteriorly compressed, transversely elongated, and at the wear stage in which the dentine lake extends over about half the width of the crown. The median transverse valley is extremely narrow from just above cervix level to the occlusal surface of the tooth, as in other specimens of Nguruwe . The m3 is similar to the m2 save for the presence of a large talonid cusp positioned slightly buccal to the mid−line of the tooth. The posterior transverse valley of this tooth possesses low tubercles buccally and lingually and there is a low tubercle at the buccal extremity of the median transverse valley.
Lower third molars of N. kijivium from Wadi Moghra are simple, bunodont teeth with a small almost centrally positioned talonid ( Fig. 5C View Fig ). WM DEC06−55 shows a medium amount of wear, with dentine showing at the apices of the two anterior cusps, and all evidence of the furchen abraded away. The enamel is thick as in specimens of this genus from East Africa and Namibia ( Pickford 1986, 1987, 1995, 1997, 2003, 2004). The hypoconulid is located slightly to the buccal side of the central line, and it has cingular crests running antero−buccally and antero−lingually. The anterior cingulum is narrow and extends slightly onto the buccal side of the protoconid. The anterior accessory cusplet is deeply worn, being barely perceptible. The median accessory cusplet is heavily worn showing a transversely elongated wear facet occupying about half the extent of the transverse valley. This is similar to the situation observed in East African and Namibian specimens of the species that are worn to a comparable stage. The posterior accessory cusplet lies anterior to the hypoconulid in the midline of the tooth. Cingular remnants block the buccal ends of the median and posterior transverse valleys, but there is no cingulum at the lingual end of the median transverse valley. The dimensions of these teeth are close to those of Nguruwe kijivium from Eastern and Southern Africa ( Table 2). In addition, Tables S3 and S4 (see Supplementary Online Material at http://app.pan.pl/SOM/app55-Pickford_etal_SOM.pdf) compare M3 and m3 dimensions of Kubanochoerinae from Moghra with a large sample of other African and Eurasian kubanochoerines.
Remarks.—Fossils from Moghra attributed to Nguruwe kijivium are similar to specimens of this taxon from East Africa and Namibia. This species ranges in age from about 20–18 Ma in East Africa, and up to about 17.5 Ma in Namibia. It is thus a useful marker for the upper part of the early Miocene, and possibly the base of the middle Miocene. The deposits where this species has been found are usually correlated to MN 3 and MN
4 of the European mammal zones. Geographic and stratigraphic range.— Uganda (Napak, I, IV,
V); Kenya (Songhor, Koru, Mteitei, Mfwangano, Rusinga (Hiwegi)); Egypt (Wadi Moghra); Namibia (Arrisdrift), early to?middle Miocene.
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