Pygmoid Australomelanesian Homo sapiens skeletal remains from Liang Bua, Flores: Population affinities and pathological abnormalities

Abstract

Indonesia ͉ microcephaly ͉ skeletal pathology ͉ asymmetry ͉ dentition

Flores hominid: New species or microcephalic dwarf?

“…Falk et al (2005a) note that human pygmy skulls typically have cranial capacities exceeding 1,000 cc (compared to a worldwide mean value for all modern humans of 1,349 cc) (Beals et al, 1984). The adult female pygmy skull used in their comparison in fact had a cranial capacity of 1,249 cc, while modern Rampasasa pygmies on Flores have an average cranial capacity of 1,270 cc (Jacob et al, 2006), similar to the value of 1,204 cc reported by Jacob (1967) for the Flores ''pygmoid'' described by Verhoeven (1958). explicitly suggested that Homo floresiensis was derived from Homo erectus through a process of insular dwarfing (see also Morwood et al, 2005b), although Morwood et al (2005a) state that ''H.…”

“…1), the possibility of a pathological disorder, specifically some form of microcephaly, must be considered (Henneberg and Thorne, 2004;Jacob et al, 2006;Martin et al, 2006;Richards, 2006). This possibility was mentioned briefly in the original report , but then rejected.…”

“…Yet examination of a living modern human with similar features in a medical genetics clinic would yield the following conclusions for a young adult female with height $ 106 cm, body mass 16-29 kg, and head circumference (our estimate) 39-41 cm; relative to modern human standards, these values would be graphed at À9 to À10 standard deviations (SD) for height, À4 to À6 SD for body mass, and À10 to À12 SD for head circumference. Physical examination would reveal a recessed jaw with no chin, accompanied by congenital dental anomalies consisting of absent mandibular right P 4 and maxillary right M 3 (questioned by Jacob et al, 2006), small maxillary left M 3 , and pathological rotation of both maxillary P 4 s. [Lukacs et al (2006) provide additional comments on the dental anomalies of LB1.] The long bones of the LB1 fossil appear disproportionately broad and less modeled (less narrowing of the diaphysis) than long bones in modern humans, as would be seen on radiographs (see also Jacob et al, 2006).…”

“…Physical examination would reveal a recessed jaw with no chin, accompanied by congenital dental anomalies consisting of absent mandibular right P 4 and maxillary right M 3 (questioned by Jacob et al, 2006), small maxillary left M 3 , and pathological rotation of both maxillary P 4 s. [Lukacs et al (2006) provide additional comments on the dental anomalies of LB1.] The long bones of the LB1 fossil appear disproportionately broad and less modeled (less narrowing of the diaphysis) than long bones in modern humans, as would be seen on radiographs (see also Jacob et al, 2006). All of these abnormalities taken together would lead to diagnosis of a severe short stature with microcephaly syndrome, although the available data are not sufficient to match this to a specific known syndrome (Judith G. Hall, personal communication).…”

“…Because the Flores finds involve such a strikingly incongruous combination of a tiny-brained hominid with advanced stone tools, it is surely advisable to give serious consideration to alternative explanations (Henneberg and Thorne, 2004;Jacob et al, 2006;Martin et al, 2006;Richards, 2006). One possibility is that the individual represented by the main skeleton LB1 suffered some kind of pathology, exhibiting a form of microcephaly.…”