Brain Endocast Research Articles

Hominid Brain Volume

Having calculated the brain volumes of several australopithecine and early Homo fossil hominid brain endocasts ([1][1]–[3][2]), I read with considerable interest the report by Glen C. Conroy et al. (12 June, p. [1730][3]) and the commentary by Dean Falk (Perspectives, Science 's Compass, 12 June,

Evidence for POT expansion in earlyHomo: A pretty theory with ugly (or no) paleoneurological facts

AbstractIf POT (parieto-occipital-temporal junction) reorganization came earlier in australopithecines than inHomo, it is likely that the selective pressures were different, and not necessarily directed toward language. The brain endocast evidence for the POT inA. afarensisis actually better than it is for earlyHomo.

Relationship of squamosal suture to asterion in pongids (Pan): relevance to early hominid brain evolution.

Based on 244 measurements of the relationship of the squamosal suture to the landmark asterion in 49 chimpanzee skulls, it is shown that in the normal lateral view the squamosal suture is very rarely inferior to asterion. In hominid crania, the squamosal suture is always well superior to asterion. Even in Pan, that part of the squamosal suture most homologous with the remnant found on the Hadar AL 162-28 Australopithecus afarensis hominid cranial fragment is very rarely inferior to asterion. Such variability suggests that Falk's (Nature 313:45-47, 1985) orientation of the Hadar specimen is incorrect; she places asterion superior to the position of the squamosal suture if projected endocranially. The implication for the brain endocast is that, however the fragment is oriented, the posterior aspect of the intraparietal (IP) sulcus is in a very posterior position relative to any chimpanzee brain. The distance from the posterior aspect of IP to occipital pole is twice as great in chimpanzee brain casts than on the Hadar AL 162-28 endocast, even though the chimpanzee brain casts are smaller in overall size. This suggests that brain reorganization, at least as exemplified as a reduction in primary visual striate cortex (area 17 of Brodmann), occurred early in hominid evolution, prior to any major brain expansion.

The Indonesian Homo erectus brain endocasts revisited

AbstractNew brain endocast reconstructions of Homo erectus discoveries from Indonesia since 1963 (H. erectus VI, 1963; VII, 1965; VIII, 1969) have been made and their volumes determined. In addition, older discoveries (H. erectus I, 1891; II, 1937; IV, 1937–38) have been reendocast and reconstructed, and have yielded volumes considerably different from those previously published. This is particularly so in the case of Dubois's original discovery, which yields a volume of 940 ml rather than the widely quoted volume of 750 ml. In addition, a number of morphological observations regarding hemispheric asymmetries (petalias) are provided, which suggest a condition similar to modern Homo sapiens.

The O.H. 7 (Olduvai Gorge, Tanzania) hominid partial brain endocast revisited.

The O.H. 7 brain endocast was reexamined using a stereoplotting apparatus to quantify the amount of distortion. Some 127 measurements for each of the left and right sides were taken and treated statically by student t-tests, both in paired and grouped fashion. Grouped data indicated no significant left-right differences. Paired data suggested three small regions of distortion, which produced three pairs of left-right differences that were significantly different. Given the very local nature of these minor distortions, it is concluded that the original reconstruction by Tobias was essentially correct. In addition, multiple regression analyses of selected chord-arc dimensions suggest that a volume in excess of 700 ml is most probable.

Indonesian "Solo" (Ngandong) endocranial reconstructions: some preliminary observations and comparisons with Neandertal and Homo erectus groups.

Latex rubber brain endocasts of solo I, V, VI, X, and XI crania were prepared in order to determine accurate volumes by H2O-displacement and morphological description. The new volumes are not markedly different from previous estimates that had been done by mensuration formulae. The mean volume is 1,151 ml. The endocast surfaces, while devoid of gyral and sulcal relief patterns, do show a preponderance of left-occipital-right-frontal petalia patterns, suggesting right-handedness. Metrical observations support the viewpoint that the solo crania are more closely related to earlier Indonesia homo erectus than to Neandertals.