Photo of the Day #26: Lesser Tree Shrew

Lesser Tree Shrew

Today’s photo is of a Lesser Tree Shrew (Tupaia minor), sitting still for a split second allowing me to get a somewhat blurry shot. I wasn’t initially thinking of putting this one up today, but I thought it would be a topical choice given a new study in Scienceout this week that suggests Colugos (Family Cynocephalidae) may be more closely related to primates than Tree Shrews (Order Scandentia). Using partial genomic data from both groups (plus primates), the research team found that the colugos were more closely related to primates than the tree shrews, although we have yet to see if this relationship is supported by anatomical and paleontological data. Although I have not read the paper as yet (I do not have access to Science from home), the abstract hints at another interesting implication of the study; the researchers suggest that tree shrews arose 63 million years ago (after the Cretaceous mass extinction) but that the ancestors of modern primates and Colugos diverged during the Cretaceous about 86 million years ago (much older than the oldest known primate fossil). Again, I doubt this is the “last word” on the subject, (especially since the Colugo genome is not entirely sequenced and we haven’t yet found the fossils to determine how accurate the estimated “ghost lineage” is) and I will be keeping my eyes open to see if there is support from the fossil record for this new arrangement. If you want to read a good overview of the research, be sure to check out Anne-Marie’s summary.

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