The discovery of the strange skull of Tapejara (Kellner 1989) opened to the door to this large-crested clade, often preserved with soft tissue crests that extended the bone shape. While resembling crested Pteranodon in several aspects, all the similarities were by convergence, although the two clades did share a common ancestor in a sister to Germanodactylus rhamphastinus.
Sinopterus dongi IVPP V13363 (Wang and Zhou 2003) wingspan 1.2 m, 17 cm skull length, was linked to Tapejara upon its discovery. Derived from a sister to Germanodactylus cristatus and Nemicolopterus, the skull of Sinopterus had a convex dorsal profile created by an expanded antorbital fenestra. The lacrimal and nasal were greatly expanded. The jugal was deeper, but the orbit remained large. The mandible was deeper. The palate was relatively twice as wide. The sacrals were nearly one half of the torso, but the torso remained rather elongated. The sternal complex was pentagonal. The radius and ulna were elongated. Manual 3.1 was longer than m2.1. Manual 4.1 was longer than the metacarpus. Manual 4.2 extended past the elbow. Metatarsal 3 was the longest. The proximal pedal phalanges were elongated such that p1.1 was subequal to p2.1 and p3.1.
Huaxiapterus jii GMN-03-11-001 (Lü and Yuan 2005) Aptian, Early Cretaceous, wingspan 9.4 m, 18.5 cm skull length, was considered a distinct taxon when first described, then relegated to a species of Sinopterus. Here Huaxiapterus is indeed a distinct taxon. The skull was shorter with a pronounced “bump” on the rostrum. The antorbital fenestra was taller. The jugal leaned posteriorly. The cranial crest was shorter. The upper temporal fenestra was smaller. The mandible was deeper and shorter. The cervicals were longer and more gracile. The dorsals were longer relative to the sacrals. The short ribs indicate the torso was not deep. The caudals were vestigial. The humerus and metacarpus were longer. Fingers 1-3 were more robust. Manual 3.1 was only slightly longer than m2.1. The pelvis was smaller. The prepubis was shorter. The pubis produces a posterior process. The fibula was a vestige. Metatarsal IV was the longest. Digits II-IV were aligned distally. The proximal phalanges were shorter.
Tapejara wellnhoferi (Kellner 1989) ~108 mya, Early Cretaceous was immediately recognized as something quite different when first discovered. 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.
Tupandactylus imperator (Campos and Kellner 1997) ~110 mya, Late Aptian, Early Cretaceous is one of the most spectabular pterosaurs ever discovered. Distinct from Tapejara, the skull of Tupandactylus was longer with an even taller rostral crest and a longer cranial crest. Between them a soft tissue crest spanned these masts. The nasal, maxilla and even a process of the jugal expanded dorsally to laminate with and support the premaxillary crest. The premaxilla topped the frontal and parietal extending far posterior to the back of the skull to create an elongate bony crest that served as the base for a very large soft-tissue crest much larger in lateral area than the entire skull.
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.
Kellner AWA 1989. A new edentate pterosaur of the Lower Cretaceous from the Araripe Basin, northeast Brazil. Anais da Academia Brasileira de Ciências 61, 439-446.
Wang X and Zhou Z 2003. A new pterosaur (Pterodactyloidea, Tapejaridae) from the Early Cretaceous Jiufotang Formation of western Liaoning, China and its implications for biostratigraphy. Chinese Science Bulletin 48:16-23.
Li J, Lü J and Zhang B 2003. A new Lower Cretaceous sinopterid pterosaur from the Western Liaoning, China. Acta Palaeontologica Sinica 42(3):442-447.
Lu J, Jin X, Unwin DM, Zhao L, Azuma Y and Ji Q 2006. A new species of Huaxiapterus (Pterosauria: Pterodactyloidea) from the Lower Cretaceous of Western Liaoning, Cina with comments on the systematics of Tapejarid pterosaurs: Acta Geologica Sinica, v. 80, n. 3, p. 315-326.7. (H. corrollatus)
Lü J, Gao Y, Xing L, Li Z and Ji Q 2007. A new species of Huaxiapterus (Pterosauria: Tapejaridae) from the Early Cretaceous of Western Liaoning, China: Acta Geologica Sinica, vol.81, no.5, p.683-687. (H. benxiensis)
Lü J and Yuan C 2005. New Tapejarid Pterosaur from Western Liaoning, China. Acta Geologica Sinica 79 (4): 453-45 (H. jii)