Zhenyuanlong

Name: Zhenyuanlong ‭(‬Zhenyuan’s dragon‭)‬.
Phonetic: Zen-yu-an-long.
Named By: Junchang Lü‭ & ‬Stephen L.‭ ‬Brusatte‭ ‬-‭ ‬2015.
Classification: Chordata,‭ ‬Reptilia,‭ ‬Dinosauira,‭ ‬Theropoda,‭ ‬Maniraptora,‭ ‬Dromaeosauridae.
Species: Z.‭ ‬suni‭ (‬type‭)‬.
Diet: Carnivore.
Size: Holotype individual estimated to be about‭ ‬1.65‭ ‬meters long at the time of death (not including feathers).‭
Known locations: China,‭ ‬Liaoning Province‭ ‬-‭ ‬Yixian Formation.
Time period: Aptian of the Cretaceous.
Fossil representation: Partial skull and partial skeletal remains.

       Zhenyuanlong is an interesting genus of dromaeosaurid dinosaur.‭ ‬To start Zhenyuanlong has some of the proportionately shortest arms in relation to leg lengths of any dromaeosaurid,‭ ‬and at the time of the description of the genus in‭ ‬2015,‭ ‬only Austroraptor and Mahakala are known to have been even more extreme.‭ ‬The radius bone of the forearm of Zhenyuanlong is by proportion the thinnest of any previously described theropod dinosaur.
       From these arms however large pennaceous feathers‭ (‬the kind with well-developed quills‭) ‬grew and attained lengths of over twice the length of the humerus‭ (‬upper arm bone‭)‬.‭ ‬These feathers resulted in what would have looked like a wing,‭ ‬however researchers are certain that Zhenyuanlong was incapable of flight.‭ ‬For a start on the preserved skeleton there are no attachments that support the presence of strong flapping muscles like those seen in birds,‭ ‬and the size and possible weight of the Zhenyuanlong holotype individual would have also made extended gliding unlikely.‭
       The purpose of the large‭ ‘‬wing‭; ‬feathers was probably that of display,‭ ‬though it is not impossible that the wings may have been held out to improve stability and balance when Zhenyuanlong was running and cornering at speed.‭ ‬The rest of the body of Zhenyuanlong seems to have been covered in fluffy downy feathers that probably served and insulatory purpose,‭ ‬though secondarily also may have been coloured for display.‭ ‬One area of curiosity about Zhenyuanlong is that the rear legs don’t show the presence of large feathers similar to‭ ‬the arms,‭ ‬something quite unusual given that Zhenyuanlong has been identified as being similar to other genera such as Microraptor which do.‭ ‬However,‭ ‬the authors describing Zhenyuanlong also noted that no feathers,‭ ‬not even insulatory ones were preserved on the hind quarters.‭ ‬This raises the prospect that Zhenyuanlong either had an unusual feathering pattern,‭ ‬or that the hind quarter feathers on the first known individual were simply not preserved.‭
       Zhenyuanlong is one of a growing number of dromaeosaurs that have been discovered in Liaoning Province with other genera including Microraptor,‭ ‬Graciliraptor,‭ ‬Sinornithosaurus,‭ ‬Tianyuraptor and Changyuraptor.‭ ‬It is not yet known if all of these genera coexisted at the same time as one another,‭ ‬yet all of them show specific specialisations,‭ ‬indicating perhaps a high degree of niche partitioning amongst China’s dromaeosaurids that would allow for a fairly high number of genera to co-exist in the same ecosystems.‭ ‬Out of these genera Zhenyuanlong is noted as‭ ‬being very similar to Tianyuraptor in body,‭ ‬while the skull of Zhenyuanlong is similar to both Tianyuraptor and Sinornithosaurus in skull form.

Further reading
-‭ ‬A large,‭ ‬short-armed,‭ ‬winged dromaeosaurid‭ (‬Dinosauria:‭ ‬Theropoda‭) ‬from the Early Cretaceous of China and its implications for feather evolution.‭ ‬-‭ ‬Scientific Reports‭ ‬5:‭ ‬Article number‭ ‬11775.‭ ‬-‭ ‬Junchang Lü‭ & ‬Stephen L.‭ ‬Brusatte‭ ‬-‭ ‬2015.



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