Wednesday, August 6, 2008

'Hobbit' skull found in Indonesia is not human indeed

Since its first description in 2004, Homo floresiensis, or the Hobbit of Flores, has been attributed to a species of its own, a descendant of Homo erectus, Homo ergaster or another early hominid, such as Australopithecus. Non-believers however hold the new species for a pathological form of modern humans, Homo sapiens, or just a dwarf human like the Neolithic inhabitants of the very same island. Karen Baab and colleagues applied landmarks on the skull, and concluded Homo floresiensis is a species on its own, and related to hominins of 1.5 million years ago. We did the same, half a year earlier, and reached similar conclusion but dare to put one step further. We applied geometric morphometric analysis to the type skull of Homo floresiensis (LB1) and compared it with skulls of normal Homo sapiens, insular Homo sapiens (Minatogawa Man and Neolithic skulls from Flores), pathological Homo sapiens (microcephalics), Asian Homo erectus (Sangiran 17), African Homo habilis (KNM ER 1813), and Australopithecus africanus (Sts 5). Our analysis includes specimens that were highlighted by other authors to prove their conclusions. The geometric morphometric analysis separates the 'hobbit' from all modern humans, thus including both the pathological and the insular forms. It is further impossible to separate the 'hobbit' skull from Homo erectus. The very early hominin Australopithecus falls separately from all skulls.

Visual inspection of the skulls learned that the cranial shape of Homo floresiensis is most close to that of Homo erectus and not to that of any modern human. Apart from cranial shape, some features of Homo floresiensis are not unique but are shared with other insular taxa, such as the relatively large teeth (shared with Early Neolithic humans of Sardinia), and changed limb proportions (shared with Minatogawa Man).

We thus conclude that Homo floresiensis is a direct descendant of Asian Homo erectus and has no relation neither to primitive australopithecines nor to modern Neolithic pygmy people of Flores.

By G.A. LYRAS, M.D. DERMITZAKIS, A.A.E. Van der GEER, S.B. Van der GEER, J. De VOS. 2008. The origin of Homo floresiensis and its relation to evolutionary processes under isolation.© 2008 The Anthropological Society of Nippon

For free pdf, click here http://users.uoa.gr/~glyras/projects/Homo-floresiensis.pdf

Or go to the publisher http://www.jstage.jst.go.jp/browse/ase

The effect of insularity on the five-horned deer Hoplitomeryx (Late Miocene, Italy)

Island studies increase our understanding of the effects of habitat fragmentation. The study of the Tertiary paleo-island Gargano is an important contribution, because of the long-term isolation under less fluctuating climatic conditions, free from anthropogenic influences; such a situation does not exist in the Quaternary period nor in the Holocene period. This makes the Gargano a unique case to study the effects of insularity in isolation. Here, a highly endemic, unbalanced vertebrate fauna evolved including the five-horned deer Hoplitomeryx. Its post-cranial material contains four size groups, based on the metapodals. In this study, the humerus and radius are described. The question whether the morphotypes are chronomorphs or ecomorphs is addressed. Sexual dimorphism is ruled out as the underlying principle of size separation in this case, based upon body mass estimations and data from living deer. Chronomorphs is the best explanation for the Megaloceros cazioti lineage (Pleistocene, Sardinia) and the Myotragus balearicus lineage (Pliocene–Holocene, Mallorca). Ecomorphs are a better explanation for the size groups of Candiacervus (Late Pleistocene, Crete) and Cervus astylodon (Late Pleistocene, Ryukyu Islands, Japan). An adaptive radiation into several trophic types took place, promoted by the ecological meltdown of the ancestral niche. The drive behind this speciation is increased interspecific competition. For Hoplitomeryx, although the hypothesis of chronomorphs cannot be discarded, that of ecomorphs seems most likely, based upon the coexistence of two or more size groups per fissure, and upon the presence of a huge morphotype, larger than mainland species, in the younger fissures.

Read more in VAN DER GEER A.A.E. (2008). The effect of insularity on the Eastern Mediterranean early cervoid Hoplitomeryx: the study of the forelimb. Quaternary International 182, 1: 145-159. See http://dx.doi.org/10.1016/j.quaint.2007.09.021 or ask me a pdf (geeraae@geol.uoa.gr).

For more general information of this enigmatic Late Miocene 'deer', see my Wikipedia page at http://en.wikipedia.org/wiki/Hoplitomeryx