Friday Elephant Shrew Blogging

Elephant Shrew Posted by Hello

The above critter may be related to an ancient order of mammals called condylarths.
From Geotimes:

The fossil, encased in hematite, was actually unearthed decades ago from the early-Eocene Willwood Formation in the Bighorn Basin of Wyoming, says Shawn Zack, a graduate student in functional anatomy at the Johns Hopkins University School of Medicine in Baltimore, Md. But the bones were only recently rediscovered and identified by Zack and colleagues as belonging to Apheliscus chydaeus, a member of a group called condylarths, early hoofed mammals that were present in North America.

Working with Jonathan Bloch, assistant curator of vertebrate paleontology at the Florida Museum of Natural History at the University of Florida in Gainesville, Zack’s team realized that some fossils in the Florida museum’s collection might be related as well. Comparing the leg and foot bones to those of living elephant shrews, they concluded that condylarths are closely related to modern elephant shrews, which they described in the March 24 Nature.

Other studies, based on jaws and teeth, had previously suggested a possible link between condylarths and modern elephant shrews, Zack says. But some are not convinced that the new fossil is actually an afrothere, saying that similarities could have evolved independently, a point the authors acknowledge.

The importance comes from:

New fossil finds are challenging the idea that six disparate orders of African mammals — elephants, sea cows, aardvarks, elephant shrews, hyraxes, and golden moles and tenrecs — all evolved from a single common ancestor isolated on the continent of Africa by the breakup of Gondwana about 100 million years ago.
The hypothesis, put forth in 1998, classifies the six mammalian orders as a “superorder” called Afrotheria, based on molecular biology studies that found many DNA sequences in common among modern members of the group. Most living “afrotheres” are endemic to Africa.


The new discovery also highlights an ongoing debate in paleontology over how best to determine evolutionary relationships. “Molecular phylogeny” determines relationships based on genetic similarities in DNA or proteins of modern descendants, while “morphological phylogeny” determines relationships by studying the anatomy of living and extinct animals.

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