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Palmqvist, P.
On the presence of Megantereon whitei at the south turkwel hominid site, northern Kenya
2002  Journal of Paleontology (76): 928-930

WERDELIN AND LEWIS (2000) recently described a new species of the saber-tooth genus Megantereon (Mammalia, Carnivora, Felidae) from Late Pliocene (;3.5 Ma) deposits of the Nachukui Formation south of the Turkwel River in Turkana, northern Kenya (Ward et al., 1999). The new species, Megantereon ekidoit, is said to represent the earliest occurrence of this genus in Africa. It was described from a right mandibular ramus (KNM-St 23812) with i3-m1. As discussed below, the post-canine diastema is longer than the cheek-tooth row, since there does not appear to have been a third premolar (p3), and the coronoid process is relatively well developed, showing a hook-shaped morphology (Werdelin and Lewis, 2000: Fig. 1). The fourth premolar (p4) and the lower carnassial tooth (m1) show considerable wear. Two major reviews on the origin, evolution and dispersal of Megantereon have been published by Turner (1987) and by Mart?īnez-Navarro and Palmqvist (1995), respectively; surprisingly, neither of these articles were cited by Werdelin and Lewis (2000). The saber-tooth genus Megantereon shares much in common with Smilodon, and both genera form the tribe Smilodontini. The earliest presence of Megantereon is recorded at 4.5 Ma in the Bone Valley Formation (Florida), where it is represented by Megantereon cultridens. This species dispersed from North America before 3.5 Ma, to extend all over the Old World. Europe was also home to M. cultridens until the lower Pleistocene, and in China it lingered well into the middle Pleistocene (e.g., at Choukoutien Locality I). In a comprehensive review of the systematics of Megantereon in the New and Old World, Turner (1987) considered M. cultridens to be the only valid species for this genus; however, his analysis was based on the morphology and dimensions of the lower carnassial, the tooth that shows least interpopulational variability and greatest conservatism in the evolution of the genus. The comparative study by Mart?īnez-Navarro and Palmqvist (1995) of Megantereon remains followed a multivariate approach using both principal component and discriminant analyses of tooth measurements. The results of the their study showed that M. cultridens gave rise in Africa to a new species, Megantereon whitei, characterized by a reduction in the size of both the maxillary carnassial (P4) and the mandibular premolars, particularly p3; the extreme reduction of the latter tooth is reflected in the appearance of a diastema between p3 and p4. M. whitei survived in Africa until 1.5 Ma (Turner, 1990), and is recorded at South Africa (Sterkfontein, Elandsfontein, Schurveburg, Kromdraai, Swartkrans) and East Africa (Omo, East Turkana, Koobi Fora) (Mart?īnez-Navarro and Palmqvist, 1995). The time range of M. whitei in Africa comprises from ;3 Ma (Sterkfontein Member 2) to ;1 Ma (Swartkrans Member 3) (Mart?īnez-Navarro and Palmqvist, 1995). Megantereon whitei dispersed to Eurasia at the Plio-Pleistocene boundary, as recorded at Orce (Guadix-Baza Basin, Spain), Apollonia (Mygdonia Basin, Greece) and Dmanisi (East Georgia, Caucasus) (Mart?īnez-Navarro and Palmqvist, 1995, 1996). The arrival of this machairodont in Eurasia may well have played a significant role in facilitating the dispersal out of Africa of the giant, shortfaced hyena Pachycrocuta and the first representatives of the genus Homo, since Megantereon seems to have been an ambushpredator with great killing capability in relation to its nutritional requirements (Arribas and Palmqvist, 1999). Presumably it left relatively large amounts of flesh and all nutrients within bones in the carcasses of its ungulate prey; such resources could be subsequently scavenged by both hyenas and hominids (Palmqvist et al., 1996; Arribas and Palmqvist, 1998; Palmqvist and Arribas, 2001). The goal of this article is to show that mandibular ramus KNMSt 23812, attributed by Werdelin and Lewis (2000) to M. ekidoit, is not a new species of Megantereon, and that this specimen can be confidently assigned to M. whitei.

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