A new paper by Sullivan, et al. (2014) reviewed the current knowledge of the vertebrates of the Jurassic Dauhugou Biota of northeastern China. That list included several lepidosaurs and pterosaurs. Unfortunately their review included several calls for “more testing” to determine phylogenetic relationships. We’ll review those here.
1. Indeterminate Squamate A (IVPP V14386, Figs. 1, 2) was considered a juvenile (total length >9cm) distinct from Dalinghosaurus, but the authors lamented that insufficient morphological information was present to justify the erection of a new taxon.
Not sure why Sullivan et al. decided there was insufficient morphological evidence here. I found every major bone but some mid-vertebrae (Fig. 2). It was like looking at an X-ray! This IVPP specimen does indeed nest with Dalinghosaurus and Homoeosaurus at the base of the Tritosauria, a third clade of lizards that Sullivan et al. evidently don’t care to consider. And that may be the source of their confusion because this specimen doesn’t nest within the Squamata. Distinct from Dalinghosaurus, the IVPP specimen has a wider skull (based on the exposed palate), a shorter ventral pelvis, no anterior scapulocoracoid fenestration and several other distinct traits.
2. Indeterminate Squamate B (IVPP V13747) (total length > 12cm) was considered a possible scleroglossan. The large reptile tree found it (the Daohugou lizard in the large reptile tree) also nested with basal tritosaurs.
3. Jeholopterus ningchengensis (IVPP V12705) was correctly considered an adult and referred to the Anurognathidae. Sullivan et al. reported this specimen, “may represent the smallest known adult pterosaur.” This is far from true, and reflects antiquated thinking regarding ontogeny and bone fusion, along with a refusal to consider tiny Solnhofen pterosaurs adults themselves.
The referred specimen (CAGS-IG-02-81) was considered a juvenile by Sullivan et al. because some long bones were half as long. Unfortunately no reconstructions were attempted. If the workers had only taken this step they would have realized immediately that these two specimens are not even congeneric. Their skulls are nearly the same size. Their post-crania differ greatly. The more gracile one attacked insects. The more robust one attacked dinosaurs for their blood.
4. Dendrorhynchoides mutoudengensis (originally GLGMV 0002, but now JZMP-04-07-3, but this is also the Boreopterus specimen number) was listed, but Sullivan et al. placed doubt on the referral of this specimen to this Dendrorhynchoides. And for good reason! The referred specimen (Fig. 4) nests with the flathead pterosaur, SMNS 811928, both derived from the holotype of Dendrorhynchoides (Fig. 4). Note the tail is even longer on the holotype as we noted before.
5. Fenghuangopterus lii (CYGB-0037) was considered small, but with an unclear ontogenetic stage. It was originally considered a scaphognathine, but the large pterosaur tree nests it as a long-legged, basal dorygnathid, so not too far from Scaphognathus.
6. Jianchangopterus zhaoianus (YHK-0931) was originally considered small, but a subadult scaphognathine related to Sordes. By contrast, Sullivan et al. wrote “it represents a very young individual.” and it’s relation to other pterosaurs “requires testing.” I have done that testing and this small adult specimen nests between Ningchengopterus and the new Painten pterosaur, all at the base of the genus clade, Pterodactylus. Here (Fig. 5) all three are compared to Sordes.
7. Qinlongopterus guoi (D3080, D3081) was considered a young juvenile very similar to Rhamphorhynchus due to its small size, large orbit and short rostrum. The large pterosaur tree nests it within that genus, close to other small rhamphs. Hone et al. (2012) noted that “juveniles of different pterosaur taxa are harder to distinguish than adults.” That may be so because Hone et al. does not care to test these small pterosaurs in phylogenetic analysis. If they took this little step they would find that, like Zhejiangopterus, Pteranodon and pterosaur embryos, which are identical to adults and can be scored with adults in phylogenetic analysis. In similar fashion Hone deleted fenestrasaurs when he and Benton wrote two papers supporting the archosaur origin for pterosaurs (without providing a viable archosaur candidate with pterosaur traits).
8. Changchengopterus pani (CYGB-0036) was considered a young juvenile by Sullivan et al. but it nests with other small pterosaurs, like the BSP 1994 specimen of Eudimorphodon at the base of all higher single cusp tooth pterosaurs. The referred specimen is a wukongopterid, as Wang (2010) erroneously suggested for the holotype. Sullivan et al. considered the phylogenetic position of these two specimens uncertain. They considered the holotype “one of the smallest pterosaurs specimens known” and considered it a juvenile due to its unfused scapulocoracoid, not realizing that this trait is phylogenetic in distribution, not ontogenetic.
9. Darwinopterus, Wukongopterus, Kunpengopterus, Archaeoistiodactylus are here all lumped together because they all form a clade, the Wukongopteridae, that left no descendants, but developed a long pterodactyloid rostrum and neck by convergence. Unfortunatelly Sullivan et al. followed Lü et al. in supporting their analysis that placed Darwinopterus at a transitional node from long tail rhamphs to short tail pterodcs. Of course the lack of resolution at this node was massive, with no single genus preceding or succeeding Darwinopterus. Nor did Lü et al include the actual transitional taxa, the tiny pterosaurs, which they considered juveniles unworthy or potentially disruptive of analysis. A more inclusive analysis can be seen here. To the credit of Sullivan et al. followed Martill and Etches (2013) and the pterosaurheresies and reptile evolution to break with the original nesting of Archaeoistiodactylus with the ornithocheirid Istiodactylus to suggest (without phylogenetic analysis) that it nested with wukongopterids.
Martill DM and Etches S2013. A new monofenestratan pterosaur from the Kimmeridge Clay Formation (Upper Jurassic, Kimmeridgian) of Dorset, England. Acta Palaeontologica Polonica 58 (2): 285–294. doi:10.4202/app.2011.0071.
Sullivan C, Wang Y, Hone DEW, Wanga Y, Xu X and Zhang F 2014. The vertebrates of the Jurassic Daohugou Biota of northeastern China. Journal of Vertebrate Paleontology 34(2):243-280.