STL Science Center

STL Science Center

09 December 2015

Forgotten Yesterday

(C) Matt Martyniuk
I lost track of time yesterday and have to backdate this post. That is all well and good though on the internet. The first anatomical thing worth mentioning about Jeholornis is the long tail. The tail of this small bird is very dinosaur-like in its anatomy. It is a long slender tail that appears to have been covered in small(ish) feathers down the length of the appendage. The end of the tail is covered in fan shaped brush like set of retrices that look something like a cat-tail (the plant not the mammal) in silhouette. Long tails like this are not unheard of in the bird world as birds such as magpies often have long tails that are as much for display as they are for controlling flight. Perhaps the reason for this long tail was for display, but it could have also been used to steer an otherwise somewhat unwieldy bird through the air during powered flight. Barring that, and assuming that Jeholornis was a good flyer, it may be the simplest explanation and the tail may have been for display purposes only.

The claws on the wings of Jeholornis are also of great interest. One of the age old questions surrounding birds is when did the hands change such that they no longer ended in claws, but only phalanges supporting feathers? As more and more fossil birds come to light the timeline of clawlessness becomes slightly clearer. It may not ever be definitively known when clawed wings gave way completely to feather only wings, but it would be interesting to discover. The claws of Jeholornis are fairly small and appear almost as an afterthought of development, but even this appearance does not make the phylogeny of clawed wings distinctly clearer. Regardless, Jeholornis is a small bird that still resembles a dinosaur in many ways and has, through a bit of luck, been preserved in significant numbers in the fine sediments of the Hebei Province.

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