Lü et al. (2012) erected a new genus and species for a new rhamphorhynchid from the Tiaojishan Formation of China (Mid/Late Jurassic). They reported, “Qinglongopterus is strikingly similar to Rhamphorhynchus and more closely related to this taxon than to any other rhamphorhynchine.”
Lü et al. (2012) considered the Qinglongopterus specimen immature due to lack of fusion in the scapula + coracoid, carpals, extensor tendon epiphysis, pubis and ischium, etc. However they noticed, “external bone surfaces appear to be fairly well ossified and do not exhibit the coarse, fibrous texture evident in the rostrum and limb bones of embryos.”
Lü et al. (2012) considered their find an archosaur. They used Euparkeria for an outgroup taxon. While noting similarities to Rhamphorhynchus and considering the specimen immature, oddly Lü et al. (2012) did not test their find against any so-called “immature” Rhamphorhynchus specimens. Their analysis of 37 taxa recovered 550 trees and nested Qinglongopterus with R. muensteri.
That’s 549 Red Flags
IMHO, that’s way too many MPTs for so few taxa.
Testing All the Above
Qinglongopterus was inserted into the matrix of the large pterosaur study, which included eleven Rhamphorhynchus specimens of all sizes. Having so many possible nesting partners covers more contingencies and minimizes problems with taxon exclusion. Here, employing 183 taxa, one MPT (most parsimonious tree) was recovered. That’s complete resolution and inspires high confidence that this tree mirrors nature’s own. Qinglongopterus was recovered as a successor to the BMM Rhamphorhynchus and a predecessor to Wellnhofer’s (1975) No. 10 and No. 11, three Rhamphorhynchus specimens generally and traditionally considered juveniles. But they were not juveniles. They were small adults as demonstrated earlier using phylogenetic analysis. Small specimens are typically found at the bases of all major pterosaur clades as size reduction accompanies major morphological changes in the Pterosauria. Even their feet were distinct (Fig. 2)
Is Qinglongopterus a Rhamphorhynchus?
You decide. If the phylogenetic predecessors of Qinglongopterus were Rhamphorhynchus and its phylogenetic successors were Rhamphorhynchus, what is Qinglongopterus? This is an awkward nomenclature situation akin to the nesting of Nesodactylus within Campylognathoides and Eosipterus within Germanodactylus.
Taxon Exclusion Restricts Nesting Possibilities
Unfortunately Lü et al. (2012) did not test for the possibility that Qinglongopterus might have nested within Rhamphorhynchus by restricting their taxon list to only one Rhamphorhynchus despite a wide gamut of morphological variation within that genus. Adding a few small specimens of Rhamphorhynchus would have tested their ontogenetic and phylogenetic concerns.
Is Qinglongopterus a new Species of Rhamphorhynchus?
Yes. Distinct from sister taxa in the present study manual 2.2 was longer than m2.1. Manual 3.3 was not as long as m3.1 + m3.2. The pes/tibia ratio was relatively smaller than in sisters. Pedal 2.1 was longer than p3.1. The sternal complex was wider than long. Otherwise Qinglongopterus retains certain plesiomorphic traits retained from the BMM specimen and displays certain derived traits not found in the BMM specimen but found in No. 10 and No. 11, like the pointed jaws. The pes of Qinglongopterus is similar to the pes in the BMM specimen (Fig. 2) and the pes of No. 11 .
Is Qinglongopterus Immature?
All sister taxa share the same lack of fusion enjoyed by Qinglongopterus. Earlier we discussed lack of fusion as a phylogenetic trait, not an ontogenetic one. It’s important to remember that pterosaurs do not follow archosaur ontogenetic patterns because they are not archosaurs. Maisano (2002) spelled out the “rules” for lepidosaurs, and pterosaurs follow them.
Fusion Patterns in Pterosaur Ontogeny
Three pterosaur embryos (IVPP specimen, JZMP specimen and Pterodaustro) all have an unfused scapula and coracoid. So do sister taxa (Dimorphodon? weintraubi and Boreopterus) and adults (Pterodaustro). The less developed and largely unossified embryo Darwinopterus had an unfused scapula and coracoid. It’s mother and all sister taxa back to Pterorhynchus fused those elements.
When does fusion take place in taxa with a fused scapulocoracoid?
Maybe at hatching. Maybe later. We don’t know at present.
By the way…
I wrote to Drs. Lü and Unwin asking why they did not test any purported juvenile Rhamphorynnchus specimens against Qinglongopterus. When I hear from them, I’ll update this blog.
As always, I encourage readers to see specimens, make observations and come to your own conclusions. Test. Test. And test again.
Evidence and support in the form of nexus, pdf and jpeg files will be sent to all who request additional data.
Lü J, Unwin DM, Zhao B, Gao C and Shen C 2012. A new rhamphorhynchid (Pterosauria: Rhamphorhynchidae) from the Middle/Upper Jurassic of Qinglong, Hebei Province, China. Zootaxa 3158:1-19. online first page
Maisano JA 2002. Terminal fusions of skeletal elements as indicators of maturity in squamates. Journal of Vertebrae Paleontology 22: 268–275.