New ScientistOne of the odder aspects into the investigations into whether Liang Bua 1 represents a diseased modern human or an entirely new and unexpected species of Homo is the way most attention has been paid to the cranial material, when from quite an early stage it became apparent that significant elements of the post-cranial material appeared to be anomalous, in that modern features weren't observed.
In this linked report, the researchers have concentrated their attention on the foot bones, and in the process have come up with some surprising suggestions - as we see...
Tolkien's hobbits walked an awful long way, but the real "hobbit", Homo floresiensis, would not have got far.
Its flat, clown-like feet probably limited its speed to what we would consider a stroll, and kept its travels short, says Bill Jungers, an anthropologist at the State University of New York in Stony Brook.
"It's never going to win the 100-yard dash, and it's never going to win the marathon," he says.
He presented his conclusion at last week's meeting of the American Association of Physical Anthropologists in Columbus, Ohio.
By analysing the nearly complete left foot of an 18,000-year-old hobbit skeleton dubbed LB1, found on the Indonesian island of Flores , Jungers' team estimated the length of the hobbit's feet, which were unusually large for its metre-high frame. "Sort of like a young girl wearing her mum's shoes," Junger says.
It also sounds similar to the effect one might get walking around wearing a pair of diver's flippers - and indeed would have made actions like running, very difficult indeed - if there had been any predatory fauna on Flores, I imagine the human population would have been wiped out fairly quickly...Jungers and other researchers who claim the hobbit was a distinct species from Homo sapiens point to the foot as further evidence supporting their theory. It has been suggested that the hobbit suffered from a severe block to growth known as cretinism or a disease called microcephaly that leads to miniaturised heads.
"It puts another nail in the coffin of the disease hypothesis," says Henry McHenry, an anthropologist at the University of California, Davis who saw the presentation.
But the feet don't solve the bigger mystery of where H. floresiensis originated, McHenry says. "It's so strange," he muses.
It might be possible they evolved from an earlier H. erectus population on the island, whose tools found there date back at least 840,000 years - but the mystery of how H. erectus themselves got to Flores is another of those nagging mysteries that won't go away.
It has also been noted that the hands of LB1 are somewhat different from modern H. sapiens, and on that note, here's part of a paper I came across in the Journal of Anatomy, specifically the part which deals with H. floresiensis...
Homo floresiensis
The recent discovery of a hominin species on the Indonesian island of Flores adds significantly to our knowledge of early hominin wrist morphology despite the fact that this material dates to only 0.018 Ma (Brown et al. 2004; Morwood et al. 2004, 2005; Tocheri et al. 2007a,b). Although its relationships to other hominin taxa remain a topic of lively debate, there is little doubt that the morphology of its partially preserved wrist is remarkably primitive (Tocheri et al. 2007a,b). Two additional facts underscore the importance of the H. floresiensis partial wrist to our understanding of early hominin hand evolution. Firstly, with four articulating elements preserved, it is the most complete primitive hominin wrist recovered from a single individual (LB 1). Second, it was recovered in direct association with cranio-dental and additional postcranial material (Brown et al. 2004; Morwood et al. 2004, 2005; Tocheri et al. 2007b), an otherwise rare occurrence in the hominin fossil record.The scaphoid (LB 1-44) has a congenitally fused centrale (Table 1, F) (Tocheri et al. 2007a,b), which is a synapomorphy of the Gorilla-Pan-Homo clade (Huxley, 1863; Begun, 1992; Richmond et al. 2001; Kivell & Begun, 2007). The articular surface for the trapezium on the scaphoid does not extend out onto the scaphoid tubercle (Table 1, H) (Tocheri et al. 2007a,b). No scaphoids have yet been described for any hominin dating to 2 Ma or older, but overall the LB 1 and OH 7 scaphoids are similar to those of African apes. This evidence suggests that all hominin species descended from the hypothetical ancestors present at Nodes 4 through 9 (Figs 4, 5) will also likely show similar scaphoid morphology, unless the scaphoid has become uniquely derived (autapomorphic) within a particular hominin lineage. The scaphoid articular facets on the trapezium and capitates of Australopithecus, which suggest a primitive scaphoid shape, are consistent with such an assessment.
The trapezoid (LB 1-47) is wedge-shaped (Table 1, J) and its articulation with the capitate (LB 1-45) is relatively small and more dorsally placed (Table 1, L) (Tocheri et al. 2007a,b). The radial side of the capitate neck is ‘waisted’ (Table 1, M) and the articular surface for the second metacarpal base is oriented more radio-ulnarly (Table 1, N) (Tocheri et al. 2007a,b). All of these features are remarkably similar to those of extant great apes in general, and African apes in particular (McHenry, 1983; Lewis, 1989; Tocheri et al. 2005, 2007).
Again, this suggests that all hominin species descended from the hypothetical ancestors present at Nodes 4 through 9 (Figs 4, 5) will also likely show similarly primitive wrist morphology. The radio-ulnar orientation of the capitate-second metacarpal joint of LB 1 (Table 1, N), however, raises an important issue. This is the second fossil wrist bone (the other is the OH 7 trapezium) to exhibit a primitive joint configuration with the second metacarpal base. Recall that Au. afarensis and Au. africanus (but not Au. anamensis) show configurations that are derived relative to Pan, Gorilla, and the Pan-Homo LCA.
These two derived features in Australopithecus have generally been considered synapomorphies with modern humans, but the OH 7 trapezium and the LB 1 capitate indicate that more fossil and comparative evidence is necessary to resolve the polarity of these particular characters as well as test whether they are in fact homologous in Australopithecus and modern humans.
Although descriptions of the incomplete hamate (LB 1-46) and metacarpal shaft (LB 1-59), as well as several hand phalanges (LB 1-40, -42, -48 , -49, -55), remain unpublished at present, these elements will likely shed further light not only on the hand of H. floresiensis but also inferentially regarding the hands of earlier hominin lineages.
In total, the relatively complete scaphoid, trapezoid, and capitate of H. floresiensis enable the resolution of several conditions present in the hand of the hypothetical ancestor at Node 8 (Fig. 5), which corresponds to the origin of the genus Homo (and perhaps Paranthropus) as presently defined (Wood & Collard, 1999; Wood & Richmond, 2000). These primitive hand features were also probably present in the hypothetical ancestors at Nodes 4 through 9 (Figs 4, 5), which include the Pan-Homo LCA.
Reading between the lines, I get the impression here that the anatomical details argue against LB1 being a diseased modern human, and taken with the research into the feet, present an even stronger case for H. floresiensis being a separate species in its own right. The details of the paper from which this is excerpted are as follows...
0 comments:
Post a Comment