Early Cretaceous Longicrusavis houi under DGS

A complete and articulated,
except for a skull suspiciously emerging from/near the cloaca, Early Cretaceous ornithuromorph bird, Longicrusavis houi (O’Connor, Gao and Chiappe 2010; PKUP V1069), gets the DGS treatment today. That involves segregating the bones by coloring them, then rearranging them to an in vivo pose. This is done without seeing the specimen firsthand. You can see what little the authors saw in figure 1.

Figure 1. Skull of Longicrusavis houi in situ, as originally traced and colorized using the DGS method. Below is a reconstruction based on the colored bones. The palate was not reconstructed, but palatal bones are colored.

Figure 1. Skull of Longicrusavis houi in situ, as originally traced and colorized using the DGS method. Below is a reconstruction based on the colored bones. The palate was not reconstructed, but palatal bones are colored. Quite a bit more data is gleaned without having seen the fossil firsthand here. The occiput is well exposed here. Possible squamosal/quadratojugal contact here. The lacrimal was displaced to the dorsal frontal. The caudals intersect the skull and push the jugal (cyan) dorsally.

After analysis,
Longicrusavis nests in the large reptile tree (LRT, 1027 taxa) at the base of the Yanornis + Changzuiornis clade and these are sisters to Apsaravis + Ichthyornis and Gansus + Hesperornis among the basalmost neognaths. The O’Connor team recovered a similar nesting with a different list of taxa.

Figure 2. It's always valuable to see what the taxon looks like with scale bars. This is a tiny specimen, but rather completely known.

Figure 2. It’s always valuable to see what the taxon looks like with scale bars. This is a tiny specimen, but rather completely known. If you have a typical 72 dpi screen, the images is 1.5x life size.

O’Connor et al. report,
“There are no teeth preserved in PKUP V1069, though alveoli do appear to be present in the premaxilla and maxilla.” I see tiny teeth (Fig. 1). Phylogenetic bracketing indicates it could go either way as derived members of this clade redevelop teeth. The jugal, lacrimal, quadratojugal and several other bones were also overlooked by those who had firsthand access. We’ll see as time goes by and better data comes in.

References
O’Connor JK, Gao K-Q and Chiappe LM 2010. A new ornithuromorph (Aves: Ornithothoraces) bird from the Jehol Group indicative of higher-level diversity. Journal of Vertebrate Paleontology 30(2):311–321.

PKUP, Peking University Paleontological Collection, Beijing, China

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