SVP 8 – a new wukongopterid from China

In an SVP abstract
Cheng et al. 2015 describe a new wukongopterid, but have several issues to get over.

Figure 1. Click to enlarge. The five specimens of Darwinopterus to scale and in phylogenetic order preceded by six more primitive taxa. The ZMNH 8802 specimen is a female associated with an egg. The others genders shown are guesses by Lü et al. 2011a. Note the skull did not elongate, it actually shrank in the vertical dimension, probably reducing its weight. The female is crestless because it is the most primitive of the five known Darwinopterus specimens. The odds that the remaining four specimens are all males is relatively small.

Figure 1. Click to enlarge. The five specimens of Darwinopterus to scale and in phylogenetic order preceded by six more primitive taxa. The ZMNH 8802 specimen is a female associated with an egg. The others genders shown are guesses by Lü et al. 2011a. Note the skull did not elongate, it actually shrank in the vertical dimension, probably reducing its weight. The female is crestless because it is the most primitive of the five known Darwinopterus specimens. The odds that the remaining four specimens are all males is relatively small.

From the abstract – asterisks have replies below:

The Wukongopteridae comprises a group of long-tailed flying reptiles that combine typical characteristics of basal (non-Pterodactyloidea) and derived pterosaurs (Pterodactyloidea)*. To date, it contains three genera: Wukongopterus, Darwinopterus, and Kunpengopterus**, and potentially also includes Changchengopterus***. Although known from several specimens, there is still a general lack of knowledge about their anatomy, particularly changes during ontogeny.**** Here we report a new specimen (IVPP V17959) that can be referred to the Wukongopteridae based on the presence of a confluent nasoantorbital fenestra, elongated cervical vertebrae and a long tail. The skull and lower jaw are preserved laterally and exposed in left view, lacking the rostral tip. The premaxilla bears a low ossified crest, which is confined to the anterior part of premaxilla and possibly extends to the rostral tip. This differs from Wukongopterus, in which the anterior dorsal margin of the premaxilla is flat, Darwinopterus, which shows a bony premaxillary crest starting anterior to the nasoantorbital fenestra reaching the skull roof*****, and Kunpengopterus, which lacks a cranial crest. The nasal bears a ventral process formed by contralateral fusing elements. Although broken, it is clear that this process almost reaches the ventral margin of the nasoantorbital fenestra. This process differs from the short and inclined nasal process of Darwinopterus and Kunpengopterus. The postcranial skeleton of IVPP V17959 shows signs of an ontogenetically fully mature individual at the time of death, having several elements completely fused such as the scapula and coracoid, the proximal and distal carpal series, and the extensor tendon process of the first wing finger phalanx******. Besides that, opposite prepubes are in close contact with the suture between them partially open suggesting that they are about to fuse. Based on this specimen, it appears that the fusion of the prepubes occurs very late in ontogeny. The new specimen also increases the diversity of the Wukongopteridae and the non-pterodactyloid pterosaurs of the Yanliao Biota, suggesting that it was the most abundant pterosaur group represented in that region during the Jurassic.”

*So do anurognathids (just ask Brian Andres).

** The large pterosaur tree also includes Pterorhynchus, Archaeoistiodactylus and Jianchangnathus in that clade, as more basal members.

***Only the referred specimenPMOL-AP00010, not the much smaller holotype, CYGB-0036. which is closer to Sordes..

**** There should be few to no changes during ontogeny as pterosaurs are known to grow (except for their crests) isometrically, which is why many (hatchlings of the crow-sized and larger pterosaurs) can fly upon hatching.

***** Some Darwinopterus do not have a premaxillary crest.

****** Fusion is more dependent on phylogeny, not ontogeny. Remember, these are lepidosaurs.

It is worthwhile to put all wukongopterid specimens into a phylogenetic analysis. There is phylogenetic variety just in Darwinopterus, for example.

References
Cheng X et al. 2015. 
Description of a new wukongopterid pterosaur with a different type of premaxillary crest from the Jurassic of China and its implications for ontogeny. Journal of Vertebrate Paleontology abstracts.

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