Tapejara wellnhoferi (Kellner 1989) ~108 mya, Early Cretaceous was immediately recognized as something quite different when first discovered. Tapejara was derived from a sister to Huaxiapterus and phylogenetically preceded Tupandactylus (below). Sister taxa include Tupuxuara and Thalassodromeus.
Distinct from Huaxiapterus, the skull of Tapejara was shorter with a taller rostral crest. The mandible was deeper. The jugal did not lean as much.
The cervicals were shorter. The sacrals were longer (judging by the pelvis).
The humerus was more narrowly waisted. The rest of the wing was more gracile, including the fingers.
The posterior process of the pubis was further expanded creating an obturator foramen between it and the broad ischium. The prepubis was angled anteriorly. The hind limbs were shorter. The fibula was barely present.
Question: How does one decide when two fossil taxa are conspecific? Congeneric? Or simply related more closely to each other than to other taxa? The last is the easiest question to answer. A cladistic analysis helps determine the most closely related taxa from a given inclusion set. The other two decisions (and they tend to be subjective decisions) are more tricky.
In pterosaurs there is a long tradition of naming pterosaurs that look like Pterodactylus "Pterodactylus," and those that look like Rhamphorhynchus or Pteranodon "Rhamphorhynchus" and "Pteranodon." Lately however, there has been a rush to create new genera, so scientists have split fossils once assigned toTapejara into Tupandactylus and Tapejara. Is this warranted? No, according to tradition. Yes, according to morphology. However, if we follow the splitting of Tupandactylus from Tapejara, we should also split many other pterosaurs, such as those listed above. Personally, I think the splitting of genera, in this case, was too much and the splitting of species was enough. After all, there was thought that T. imperator might have been the adult form of Tapejara.
The family tree of the Ornithocephalia and Germanodactylia is here. The expanded family tree of the Pterosauria is here. |
