![]() ![]() These shared traits may have appeared independently as adaptations to a similar diet, although, as explained in a 2006 study led by Manuel Salesa, the fact that the fossil red panda Simocyon had a pseudo-thumb but lacked plant-crushing teeth suggests that red panda thumbs were initially adaptations to life in the trees and were only later co-opted for eating bamboo. Despite this distance, however, the red panda also feeds on bamboo, has enlarged molars for grinding tough food, and even has a specialized wrist bone (the sesamoid) that creates a jury-rigged, opposable “thumb“. There’s the panda bear, and then there’s the red panda ( Ailurus fulgens), which last shared a common ancestor with the giant panda over 40 million years ago. One of the prime examples of this kind of convergence comes from the two distantly-related modern pandas. Their hypothesis was that a combination of shared evolutionary constraints and similar pressures from natural selection determined the unique skull shapes of carnivorans that went vegetarian. In 2010 Borja Figueirido and co-authors looked at how many times the group of mammals which contains dogs, cats, and bears – called carnivorans – has evolved similar adaptations in their skulls to eating plants. ![]() ![]() microta skull has allowed paleontologists to identify some of the evolutionary trends that shaped this peculiar group of bears. There is much that remains unknown about the diversity of prehistoric pandas and their precise placement in time.Įven if the recent history of prehistoric pandas remains a bit fuzzy, the discovery of the A. (A follow-up paper by Wei Dong on CT scans of the brain cavities of these bears showed that a reduction in brain size went along with the reduction in body size.) Given that we still know so little about these bears, however, an evolutionary march of the pandas cannot be confirmed, and better sampling will be needed to tell whether all these fossil species represent a lineage as straight as a bamboo stem or whether there were splits which led species to overlap in time with each other. baconi before a size reduction culminating in the modern A. The authors of the 2007 description interpreted them in a straight-line march from A. ![]() baconi, but it appeared that at least some unique giant panda traits were already present about two million years ago and had just been tweaked a bit since then.Įxactly how these species relate to each other is unclear. Overall, its skull was not as heavily-built as that of the largest fossil panda, A. microta, though lacking the extra cusps seen in living pandas, were broad and well-suited to grinding, and the back of the skull was expanded for heavy chewing muscles. Nevertheless, the 2007 description of the skull by Changzhu Jin and colleagues points out that this animal shared some tell-tale characteristics associated with the modern panda’s diet of coarse, fibrous bamboo. Found in southwestern China’s Jinyin cave, this worn skull is considerably different from those of later species and looks rather puny compared next to them. The fossil that has spurred several new studies into the origins of pandas is the skull of the smallest and earliest giant panda species, Ailuropoda microta. Thanks to a single discovery, though, paleontologists have begun to piece together a better understanding of how these bears changed over time. From the known parts – especially the teeth – the fossil bears did not seem all that different from the modern pandas. Notices of most of these fossil finds were tucked away in obscure journals or were only briefly mentioned in catalogs of specimens recovered during American Museum of Natural History expeditions. The earliest potential member of the giant panda lineage is the approximately seven million year old bear Ailurarctos, but there are not any solid points between it and the later pandas to draw together. Prior to the origin of the modern panda, the larger species Ailuropoda baconi lived during the past 750,000 years, and was preceded by the poorly-known Ailuropoda wulingshanensis and a smaller species – Ailuropoda microta – which occupied China between 2 and 2.4 million years ago. A few skulls, mandibles, and other assorted fragments from caves and fissures in southwestern Asia were all that had turned up. Until recently, there was little to be said about the prehistory of pandas. What I’m wondering about is the evolutionary origin of these bamboo-eating bears. Where do giant pandas come from? Of course, the proximal answer involves a male and female panda – and maybe some panda porn, if life in captivity dampens the mood – but I’m not talking about that. ![]()
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