Dentition of Living Primates.

Snyder, Richard G.; Swindler, D. A.

doi:10.2307/2801011

Cited by 37 publications

(52 citation statements)

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“…Thanks are due to Martyn Cooke for preparation of the endocast of the microcephalic hemiskull at the Hunterian Museum, Royal College of Surgeons, London; Ken Mowbray at the American Museum of Natural History, New York, for providing initial information on the micro- Kanazawa and Rosenberger (1989), Lucas et al (1986), and Swindler (1976); for fossil hominids from Blumenberg and Lloyd (1983); for modern Homo sapiens from Brace (1979); for LB1 from Morwood et al (2005a). Gary Sawyer kindly provided measurements of the lower molars from the AMNH cast of the Lesotho microcephalic mandible.…”

Section: Acknowledgmentsmentioning

confidence: 99%

Flores hominid: New species or microcephalic dwarf?

et al. 2006

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The proposed new hominid ''Homo floresiensis'' is based on specimens from cave deposits on the Indonesian island Flores. The primary evidence, dated at $ 18,000 y, is a skull and partial skeleton of a very small but dentally adult individual (LB1). Incomplete specimens are attributed to eight additional individuals. Stone tools at the site are also attributed to H. floresiensis. The discoverers interpreted H. floresiensis as an insular dwarf derived from Homo erectus, but others see LB1 as a small-bodied microcephalic Homo sapiens. Study of virtual endocasts, including LB1 and a European microcephalic, purportedly excluded microcephaly, but reconsideration reveals several problems. The cranial capacity of LB1 ($ 400 cc) is smaller than in any other known hominid < 3.5 Ma and is far too small to derive from Homo erectus by normal dwarfing. By contrast, some associated tools were generated with a prepared-core technique previously unknown for H. erectus, including bladelets otherwise associated exclusively with H. sapiens. The single European microcephalic skull used in comparing virtual endocasts was particularly unsuitable. The specimen was a cast, not the original skull (traced to Stuttgart), from a 10-year-old child with massive pathology. Moreover, the calotte does not fit well with the rest of the cast, probably being a later addition of unknown history. Consideration of various forms of human microcephaly and of two adult specimens indicates that LB1 could well be a microcephalic Homo sapiens. This is the most likely explanation for the incongruous association of a small-brained recent hominid with advanced stone tools.

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Section: Acknowledgmentsmentioning

confidence: 99%

Flores hominid: New species or microcephalic dwarf?

et al. 2006

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“…[Evidence of the latter derives from studies of differences in tooth enamel thickness, the topography of the occlusal surfaces, and the shape of the dental arcade in gorillas and in Au. afarensis (3,4,(9)(10)(11)(12)(13). ] We note again that orangutans, the outgroup in the analysis, fall within the generalized group.…”

Section: Thementioning

confidence: 99%

Gorilla-like anatomy onAustralopithecus afarensismandibles suggestsAu. afarensislink to robust australopiths

Rak

Ginzburg

2007

Proc. Natl. Acad. Sci. U.S.A.

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Mandibular ramus morphology on a recently discovered specimen of Australopithecus afarensis closely matches that of gorillas. This finding was unexpected given that chimpanzees are the closest living relatives of humans. Because modern humans, chimpanzees, orangutans, and many other primates share a ramal morphology that differs from that of gorillas, the gorilla anatomy must represent a unique condition, and its appearance in fossil hominins must represent an independently derived morphology. This particular morphology appears also in Australopithecus robustus. The presence of the morphology in both the latter and Au. afarensis and its absence in modern humans cast doubt on the role of Au. afarensis as a modern human ancestor. The ramal anatomy of the earlier Ardipithecus ramidus is virtually that of a chimpanzee, corroborating the proposed phylogenetic scenario.hominins ͉ phylogeny ͉ ramus I n all primates, the superior end of the mandibular ramus terminates in two processes: posteriorly, the condylar process, which articulates with the base of the skull, and anteriorly, the coronoid process, which is the insertion site of the temporalis muscle. An indentation, the mandibular (or sigmoid) notch, separates these two processes.Among extant higher primates, each species shows speciesspecific characteristics of the ramus. Nevertheless, the ramal configurations in those primates that we studied clearly fall into two groups: one consists of gorillas, and the other consists of modern humans, two chimpanzee species, and orangutans. In the latter group, which shares a pattern of ramal morphology with many other primates that we examined, the coronoid process is typically lower than the condylar process; the base of the coronoid constitutes a relatively small percentage of the ramal width and tapers into a slender, pointed, superiorly directed tip (Fig. 1). This tapering produces a spacious mandibular notch between the two processes; hence, the deepest point of the notch is situated anteriorly. In gorillas, on the other hand, the coronoid process is usually higher than the condylar process. The broad base of the coronoid constitutes much of the ramal width, moving the deepest point of the mandibular notch closer to the condylar process than in what we interpret to be the more primitive (common) configuration. With the tip of the coronoid pointing posteriorly, the superior edge of the process in gorillas assumes a f lat contour; in many cases, the tip overhangs the mandibular notch, lending the process a hook-like appearance, and the notch, a narrow, deep, confined appearance. As a consequence, the notch occupies a smaller portion of the total ramal area than in the more common ramal morphology. § The ramus of an Australopithecus afarensis specimen discovered in 2002, A. L. 822-1 (Fig. 1), closely matches that of the gorilla. The specimen is a fragmentary but well preserved skull of an adult individual found in the Unda Hadar, a tributary of the Awash River running parallel to the Kada Hadar. Discovered Ϸ2.5 km east of...

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“…Table 1 shows that the Nakatsu skull has a relatively short face and wide orbits compared with D. ruscinensis, though many measurements of the latter are estimated. As for tooth size, the mesiodistal lengths of molars are around 9-10 mm in both the Nakatsu skull and D. ruscinensis (Table 2), while the range is 5-8 mm in Mesopithecus (Table 2; Delson, 1973) and in all eight species of living colobines reported by Swindler (1976).…”

Section: Description and Discussionmentioning

confidence: 99%

A Pliocene colobine from the Nakatsu Group, Kanagawa, Japan

Iwamoto

Hasegawa

Koizumi

2005

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In 1991, a partial cranium of a fossil colobine monkey was found in Kanagawa Prefecture, Japan. Its geological age is Late Pliocene (ca. 2.5 Ma). It is larger than skulls of living colobine monkeys and resembles a male example of Pliocene Dolichopithecus ruscinensis from France. However, the cranium exhibits some distinctive features, notably very thin postorbital rims (lateral margins of the orbit). Therefore, a new subgeneric and specific name Dolichopithecus (Kanagawapithecus) leptopostorbitalis is given.

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Dentition of Living Primates.

Cited by 37 publications

References 0 publications

Flores hominid: New species or microcephalic dwarf?

Flores hominid: New species or microcephalic dwarf?

Gorilla-like anatomy onAustralopithecus afarensismandibles suggestsAu. afarensislink to robust australopiths

A Pliocene colobine from the Nakatsu Group, Kanagawa, Japan

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