Homo floresiensis Gains Legitimacy

Science Daily has posted a story detailing new examination of the Liang Bua crania by researchers at SUNY Stonybrook, The University of Tubingen, and the University of Minnesota in which they grant legitimate species status to Homo floresiensis.  They write:

The scientists applied the powerful methods of 3-D geometric morphometrics to compare the shape of the LB1 cranium (the skull minus the lower jaw) to many fossil humans, as well as a large sample of modern human crania suffering from microcephaly and other pathological conditions. Geometric morphometrics methods use 3D coordinates of cranial surface anatomical landmarks, computer imaging, and statistics to achieve a detailed analysis of shape.

This was the most comprehensive study to date to simultaneously evaluate the two competing hypotheses about the status of Homo floresiensis.

The study found that the LB1 cranium shows greater affinities to the fossil human sample than it does to pathological modern humans. Although some superficial similarities were found between fossil, LB1, and pathological modern human crania, additional features linked LB1exclusively with fossil Homo. The team could therefore refute the hypothesis of pathology.

The link to the PLoS paper is here.This is the conclusion of the paper:

Our analyses corroborate the previously suggested link between LB1 and fossil Homo and support the attribution of this specimen to a distinct taxon, H. floresiensis. Furthermore, the neurocranial shape of H. floresiensis closely resembles that of H. erectus s.l. and particularly specimens of early Eurasian H. erectus, although it is unclear whether this latter affinity is best attributed to a close phylogenetic relationship or to a size-related convergence in shape. These results also counter the hypotheses of pathological conditions as the underlying cause of the LB1 neurocranial phenotype, with the possible exception of posterior deformational plagiocephaly, a condition without significant adverse health effects.

Of course, this doesn't mean that it is not endemic dwarfism, just that it is not built on a modern human base. In this case, it may represent a Homo erectus base. Why it was so marked is still an unanswered question.It is also quite possible that this represents founder effect followed by years of selection for diminutive characteristics.  It definitely represents a peculiar side branch in human evolutionary history but not one that defies explanation. 

Letters of Alfred Russel Wallace Online

The collected letters of Alfred Russel Wallace, the co-discoverer of natural selection, have been put online by the Natural History Museum.  Wallace was the subject of a chapter in the David Quammen book The Song of the Dodo: Island Biogeography in an Age of Extinction. The chapter was called "The Man Who Knew Islands." Where Darwin used the Galapagos Islands and the terrain of South America to devise his theory, Wallace used the islands of Indonesia.  The site is billed as having:

• iconic correspondence between Wallace and Charles Darwin about evolution by natural selection
• important observations and discoveries made when in the Malay Archipelago (1854 - 1862)
• fascinating discussions on a variety of subjects, scientific and social such as glaciology, anthropology, epidemiology, astrobiology, socialism, land reform and spiritualism

Wallace was a spiritualist and began to infuse his scientific writings with spiritualism, a development which dismayed Darwin, who had gone to great lengths to show that natural selection could be thought of in scientific terms, alone.

As Go the Hippos, So Goes Homo floresiensis?

One hippopotami cannot get on a bus, because one hippopotami is two hippopotamus.

(Alan Sherman)

According to news from Madagascar, island endemic dwarfism affects the development and size of the brain. Science Daily has a story on fossil remains of ancient hippopotami.

By examining the skulls of extinct Madagascan hippos, Museum scientists discovered that dwarfed mammals on islands evolved much smaller brains in relation to their body size. So Homo floresiensis may have had a tiny brain because it lived on an island. This is something which has been at the heart of the debate of the Hobbit’s origins, whose remains were uncovered on the Indonesian island of Flores in 2003.

This was put forth as an explanation some years back but this is the first time I have heard it fleshed out. Read the whole thing.