More data on the scaly fenestrasaur, Kyrgyzsaurus

Updated March 3, 2016 with a reconstruction from the tracings.

An earlier nesting
in the large reptile tree placed the Late Triassic reptile Kyrgyzsaurus not with drepanosaurs, but with fenestrasaurs, between Cosesaurus and higher taxa, all bipeds or near bipeds. The parallelogram-shaped cervicals indicate the skull was held higher than the shoulders, as in pterosaurs, Longisquama and Cosesaurus. 

Figure 1. New data on Kyrgyzsaurus provides the first evidence for forelimbs.

Figure 1. New data on Kyrgyzsaurus provides the first evidence for forelimbs. This is the first time I’ve seen the bones in color. Note: Spindler thought the forelimb was tiny, but did not trace left forelimb elements, only the elbow visible over the dorsals. This is an example of DGS. Higher resolution would enable further details to be traced.

New photos
(Fig. 1) of what appear to have come from an abstract posters provided online by Spindler et al. 2014 reveal more data for Kyrgyzsaurus, including a complete pectoral girdle and tiny forelimb with laterally folding digit 4 (as in pterosaurs), adding to the possibility that long hind limbs probably gave this taxon a bipedal configuration as well (based on phylogenetic bracketing). Longisquama and Sharovipteryx were sisters and contemporaries that likewise had short arms.

Figure 2. Updated figure of Kyrgyzsaurus.  Note the tiny forelimbs and large hyoid, as in Sharovipteryx.

Figure 2. Updated figure of Kyrgyzsaurus. Note the tiny forelimbs and large hyoid, as in Sharovipteryx.

The abstract discusses
coloration in the scales, not unexpected as exquisitely preserved Late Triassic insects likewise preserve coloration in this formation.

From the poster
“Dorsally the scales are generally smaller, but conspicuous craniocaudal rows of large oval to rectangular scales occur within the meshwork of smaller scales. The reddishly preserved skin colouration follows no simple pattern: There is a larger color patch along the posterior margin of the skull, the ventral neck and anterior trunk display scales with tiny colour spots, and the dorsal rows of larger scales are sometimes marked by thin aligned stripes.”

Figure 3. The origin of pterosaurs now includes Kyrgyzsaurus, nesting between Cosesaurus and Sharovipteryx.

Figure 3. The origin of pterosaurs now includes Kyrgyzsaurus, nesting between Cosesaurus and Sharovipteryx. Click to enlarge.

Unfortunately Spindler et al.
were unable to decipher their own precise tracings and so overlooked the forelimb of Kyrgyzsaurus. In this case it might have been important for them to understand where this specimen nested in the reptile family tree (published here in 2012). They considered it merely as ‘a reptile’ with tiny forelimbs with very, very small fingers, evidently imagined. They did not even call it Kyrgyzsaurus, or make reference to the original paper (Alfanov and Kurochkin 2011), even though the specimen was named three years earlier. It is clear that Spindler et al. did not trace fingers, but guessed at their presence. They labeled the ‘pectoral girdle’ with a vague arrow, but not the individual elements. Maybe none of this matters, as their study focused on skin coloration.

DGS
(digital graphic segregation), a reconstruction, and a phylogenetic analysis once again pulled data out of an online photo that was overlooked by first hand observers.

References
Alifanov VR and Kurochkin EN 2011. Kyrgyzsaurus bukhanchenkoi gen. et sp. nov., a new reptile from the triassic of southwestern Kyrgyzstan. Paleontological Journal 45(6): 639–647. doi:10.1134/S0031030111060025.
Spindler F, Buchwitz M, Fischer J and Voigt S 2014. Preservation of tetrapod skin in the Triassic Madygen Formation. Conference: 82. Jahrestagung der Paläontologischen Gesellschaft, At Vienna (Austria), Volume: Beiträge zur Paläontologie – Program and Abstracts 32: pp. 76–77.

wiki/Kyrgyzsaurus

 

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s