Posted by: paulgarner | August 9, 2012

Early Homo and extant graptolites

In this week’s Nature, Meave Leakey and others (2012) describe new fossils from Koobi Fora, northern Kenya, that clarify the taxonomic status of KNM-ER 1470, the type specimen of Homo rudolfensis. Ever since 1470 was discovered in 1972, there has been controversy about whether it belonged with other lower Pleistocene Homo fossils in a single, highly variable species or whether it provided evidence of multiple species of early Homo. This new study supports the multiple species hypothesis. Assuming that these early Homo species are members of the human holobaramin, it seems that post-Babel humanity underwent quite a bit of diversification and that modern human variability is much diminished from what it was in the past.

Elsewhere, Mitchell et al. (2012) present a new phylogenetic analysis suggesting that the modern pterobranch hemichordates known as rhabdopleurids should be regarded as extant graptolites, a group otherwise known only from fossils. The authors state that “Rhabdopleura nests among the benthic, encrusting graptolite taxa as it shares all of the synapomorphies that unite the graptolites.” Now I think that Rhabdopleura as a living graptolite is quite exciting. Graptolites are important zonal fossils for the Lower to Mid Palaeozoic, and were thought to be long extinct. Take my word for it: if this were a dinosaur or something it would be a big deal.

References

Leakey M.G. and six others. 2012. New fossils from Koobi Fora in northern Kenya confirm taxonomic diversity in early Homo. Nature 488:201–204.

Mitchell C.E. and three others. 2012. Phylogenetic analysis reveals that Rhabdopleura is an extant graptolite. Lethaia DOI: 10.1111/j.1502-3931.2012.00319.x.

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