Redescription of Tupandactylus imperator Campos & Keller, 1997 (Pterosauria, Tapejaridae) based on a new complete specimen from the Crato Formation (Aptian-Albian) of the Araripe Basin, Ceará, Brazil

• Autor(a) principal: Costa, Lucas Piazentin
• Data de Publicação: 2021
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Biblioteca Digital de Teses e Dissertações da USP
• Texto Completo: https://www.teses.usp.br/teses/disponiveis/41/41133/tde-14082021-135310/
• topic: . Osteology; Cretáceo Inferior; Early Cretaceous; Filogenia; Osteologia; Phylogeny; Tapejaridae; Tapejaridae; Tupandactylus imperator; Tupandactylus imperator

Formations is the Tapejaridae, with toothless beaks and high and long crests that may support a large soft tissue membrane. Of the tapejarids described for the Crato Formation, the most intriguing is undoubtedly Tupandactylus imperator Campos & Kellner, 1997, known because of its premaxillary crest, with a very high suprapremaxillary process shaped as a dorsal spine, and a very long posterior occipital crest, both anchoring a high and long soft tissue membrane. Although many tapejarid specimens are known from the Crato Formation, all species formally described are based only on cranial material, including T. imperator. The new specimen described here, MZSP-PV 1249, has an almost complete postcranial skeleton articulated with a skull and a lower jaw, allowing a precise identification at the specific level. It is one of the first postcranial material that can be referred to a named tapejarid species from the Crato Formation, being the fifth specimen officially referred to T. imperator. This specimen, a subadult, reveals that the rostral concavity present in mature tapejarids may be a possible allometric feature, with adult specimens presenting a perfect occlusion. Tupandactylus imperator shares with all Brazilian tapejarids a tetrarradiate jugal, where the quadratojugal process is directed posterodorsally. Tupandactylus, Sinopterus and Caiuajara share a suprapremaxillary process, with its morphology being unique for each genus. Tupandactylus species share the suprapremaxillary process shape and a deep mandibular crest. The retroarticular process is elongated, something unique for Tupandactylus and Sinopterus within tapejarids. The new specimen reveals that T. imperator has an autapomorphic nasal descending process morphology. Additional autapomorphies identified are the posterior occipital crest morphology, with every tapejarid species presenting unique morphologies, and a residual fourth wing phalanx. All axial and appendicular features of T. imperator match the known tapejarid pattern, including fourth and fifth mid-cervicals being the longest vertebrae, concave ventral surface of the mid-cervicals and second and third wing phalanges having a longitudinal ventral ridge. There is a fifth pedal digit in T. imperator, with a single phalanx, a feature observed on the azhdarchoids Sinopterus and Jidapterus. Two preliminary phylogenetic analyses were performed, indicating that the clade forming the family Tapejaridae is supported mainly by lower jaw characters. The preliminary phylogenetic results also indicated a closer relationship between Tupandactylus, Caiuajara and Sinopterus