Gigantopithecus and Its Relationship to Australopithecus
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Gigantopithecus and Its Relationship to Australopithecus DAVID W. FRAYER Department of Anthropology, University of Michigan, Ann Arbor, Michigan 481 04 KEY WORDS Gigantopithecus . Australopithecus . P. Gorilla . Hominid origins. ABSTRACT Gigantopithecus blacki and G. bilaspurensis are compared to P. gorilla and Australopithecus. The total morphological pattern of Giganto- pithecus mandibles is more similar to Australopithecus than to P. gorilla. Two major points are raised. (1) G. blacki might be considered an aberrant hominid rather than an aberrant pongid. (2) G. bilaspurensis can be considered an equal- ly likely candidate, along with Ramapithecus, for possible hominid ancestry. Numerous taxonomic and evolutionary topithecus and Australopithecus. Further- statements have been made concerning more, a direct comparison between the the genus Gigantopithecus. These inter- Middle Pliocene G. bilaspurensis and Aus- pretations have portrayed Gigantopithecus tralopithecus has not been done, although as ancestral to hominids, as an over-spe- Simons and Chopra (‘69a) allude to some cialized side-branch of hominids, or as basic similarities. The metric data pre- an aberrant pongid, unrelated to hominid sented below combined with a review of evolution. Weidenreich was the main pro- morphological data are intended to clarify ponent of the ancestor/descendent rela- these relationships. tionship between Gigantopithecus and DATA “Meganthropus” ( = Australopithecus) (‘45, ’46, ’49). More recently, Eckhardt (‘71, Dental and mandibular measurements ’72) has reopened the possibility of Gigan- of P. gorilla, Australopithecus, and Gigan- topithecus as a hominid forbear. Woo (‘62) topithecus appear in Appendices 1-5. and von Koenigswald (‘52, ’58) suggested Gorilla tooth dimensions were taken by that Gigantopithecus should be considered Paul E. Mahler and Milford H. Wolpoff. a hominid, but that the genus represents All mandibular measurements were taken an over-specialized side-branch which did by the author. Since all the Cleveland not contribute to australopithecine evolu- Museum of Natural History gorilla speci- tion, but became extinct. Both of these mens were wild-shot, reliable sex deter- schemes consider only G. blachi and not minations are possible. The sex of the the recently discovered Middle Pliocene specimens listed in Appendices 4-5, then, G. bilaspurensis. being determined in the field from the Simons and Pilbeam (‘65) reviewed the carcass, is quite accurate. G. blachi material and concluded that the Except for noted cases, all australopith- genus represented an aberrant pongid ecine measurements were taken on the with peculiar hominid parallelisms. Si- original specimens by Milford H. Wolpoff. mons’ subsequent discovery of the Indian These fossils are classified into gracile Gigantopithecus (G. bilaspurensis) further and robust categories based either on the confirmed, they felt, this aberrant pongid specific site (e.g., Sterkfontein = gracile) status (Pilbeam, ’70; Simons and Ettel, or on published accounts (e.g., robust and ’70; Simons and Chopra, ’69a,b; Simons gracile forms from Omo). The gracile and Pilbeam, ’72). sample includes South African specimens Throughout this debate, however, little generally described as A. africanus and substantive information has been given 1 This paper is a revised version of paper delivered which would indicate the metrical and at the 1971 meeting of the American Association of morphological similarity between Gigan- Physical Anthropologists, AM, J. PHYS. ANTHROP.,39: 413-426 413 414 DAVID W. FRAYER East African Lower Pleistocene specimens mates of posterior tooth size in gorillas described as Homo. ER-992 has been in- are more reliable when considering only cluded in the gracile sample with reserva- the summed areas of P4-M3. I have for- tions. The robust sample consists of speci- mulated the same indices using summed mens published as A. “robustus” and A. P3-Ms length and areas and have obtained “boisei.” Severely crushed and distorted results similar to those presented in ta- specimens are not included in these groups, ble 1. The inclusion of all the measure- but in some cases teeth with post-mortem, ments provides data for analysis in either matrix-filled cracks are utilized. In these manner. specimens the dimensions of the crack Each index in table 1 intends to show have been subtracted from the overall morphological characteristics through dimension, rendering a good representa- metric evaluation. The three genera are tion of the true tooth size. The notable represented by measurements presented case in this regard is the East African in indices allowing direct comparison of robust specimen, ER-818. Formal descrip- metric/morphological relationships. tions of these newly discovered East Afri- Bicanine breadth divided by the length can hominids appear in Leakey (’71, ’72) of the cheekteeth (P4-Mz) compares the and Leakey et al. (‘71, ’72). maximum external breadth outside the With the exception of bicanine breadth, canines to the length of the posterior all measurements for Gigantopithecus tooth row. The size of the canine (length blachi are taken from Woo (‘62). To my X breadth) is normalized against the knowledge published mandibular dimen- summed areas of the posterior teeth, sions for G. bilaspurensis do not exist. while the area of the lower second incisor Consequently, all dimensions on the Bilas- is compared to the area of the lower first pur mandible were taken on the Yale- molar. I have also compared lower Is area Peabody Museum cast. Checking dental with the summed posterior tooth areas dimensions from the cast with those pub- as well as lower Mz area. All indices fol- lished by Simons and Chopra (’69a), the low the same pattern, but for the sake of Yale-Peabody Museum case is within 4% brevity, have not been included in this of the dimensions on the original speci- paper. Maximum symphyseal length is men. Mandibular dimensions taken from considered in regard to the height of the the cast for the Bilaspur mandible are mandible at Mn. This index is somewhat assumed to be within 4% of the true different from that described in Simons values. Bicanine breadth on G. blachi is and Chopra (‘69a), but again demonstrates similarly accurate. Finally, dental dimen- the same morphological relationship as sions for all Gigantopithecus mandibles their index of maximum symphyseal length are published by Simons and Chopra (‘69a) divided by mandible height multiplied by and are not duplicated here. breadth at Mz and by the summed pos- METHOD terior cheek teeth area. Maximum sym- physeal length divided by corpus height at The indices presented in table 1 are in Mz better separates Australopithecus from most cases those used by Simons and P. gorilla and, for this reason, is used in Chopra (‘69a) in their taxonomic discus- this analysis. The summed areas of P4-Mz sion of G. bilaspurensis and G. blachi. In divided by height X breadth of the man- place of P3-M3 length and P3-M3 summed dible at Mz normalizes the cheek teeth areas, I have chosen to substitute P4-M2 relative to the robusticity of the mandible length and area. This substitution allows under Mz. Area (1 X b) of MI divided by for a larger sample size in Gigantopithecus height X breadth of the corpus under Mz (G. blachi I and I1 lack lower third molars) provides a further check. and in Australopithecus. It also eliminates These indices are used to demonstrate the comparison of lower third premolars morphological patterns through metric between known pongids and hominids. analysis. They provide excellent sorting Since the lower third premolar in apes is criteria for separating australopithecines a mesiodistally elongated tooth set at an from gorillas. Student’s t-tests performed angle to the tooth row and is not directly on these two genera (Australopithecus involved in grinding and crushing, esti- and P. gorilla) using the six indices all GIGANTOPITHECUS AND AUSTRALOPITHECUS 415 showed significant differences at the 0.01 contra these authors, does not specifically level. It follows, then, since the indices indicate that gigantopithecines are “aber- separate australopithecines from gorillas, rant apes.” Rather, if one has to resort that they are useful criteria for analyzing to such terminology, the close metric sim- other hominoid, and possibly related ilarity between G. blacki, G. bilaspurensis genera. and Australopithecus would better de- RESULTS scribe an aberrant hominid. Three major points can be readily seen (3) The third observation apparent from from an examination of table 1. (1) Aus- table 1 is that G. blacki and G. bilaspuren- tralopithecus differs widely from gorillas, sis show some different metric relation- a fact which has been discussed above and ships. The relative bicanine breadth and by numerous authors beginning with relative symphyseal length are both small- Dart (‘26). Different cultural and dietary er in G. bilaspurensis than in G. blacki I, adaptations are likely the major reasons I1 or 111, and one would expect the index for this metric difference. The morpho- describing lower incisor area to differ logical specialization of Australopithecus also. In some cases G. bilaspurensis closely to small object feeding has been consid- resembles Australopithecus. ered in detail by Jolly (‘70). The infie- This similarity is further emphasized quency of range overlap between Australo- when comparing G. bilaspurensis with two pithecus and P. gorilla provides new robust australopithecines from East Africa evidence for determining the phylogenetic (see table 2). Here the major differences positions of G. blacki and G. bilaspurensis. between the Bilaspur mandible, Omo 7, (2) Except in two cases (relative sym- and ER-729 relate to absolute canine size. physeal length and relative p4-M~ area, The smaller size of the bicanine breadth both in G. blacki 11), indices describing in G. bilaspurensis reflects the size of the Gigantopithecus mandibles and tooth size canines rather than the size of the incisors. fall completely within the range of Aus- The internal bicanine breadth (measured tralopithecus. Both G. blacki and G. bi- from lingual surface on the canine) dem- laspurensis overlap extensively with Aus- onstrates this clearly.