New Material of Sinopterus (Pterosauria, Tapejaridae) from the Early Cretaceous Jehol Biota of China

Abstract

tapejaridae is a clade of toothless pterosaurs typically characterized by a large nasoantorbital fenestra and a premaxillary crest that extends from the anterior to the posterior part of the skull. Sinopterus dongi was the first reported Chinese tapejarid. Another genus "Huaxiapterus" was described, but it was later on determined that "Huaxiapterus" is in fact an invalid name. here, we report on a new juvenile specimen of Sinopterus atavismus from the Jiufotang Formation of western Liaoning, China, and revise the diagnosis of this species. Sinopterus atavismus does not present a square-like crest. Moreover the feature that groove in the ventral part of the second or third phalanx of manual digit IV is not diagnostic of the species. In the new material, the skull preserves a pointed process in the middle part of the dorsal margin of the premaxillary crest, which is different from other Chinese tapejarids. Considering the new specimen is known from a large skeleton that differed from the holotype, this difference may be related to ontogeny, as the premaxillary crest of the holotype is short and does not extend as long as that of the new specimen.

Osteology of an exceptionally well-preserved tapejarid skeleton from Brazil: Revealing the anatomy of a curious pterodactyloid clade

“…The Rostral Value of GP/2E 9266 (as measured from the tip of the premaxillomaxillae to the anterior margin of the nasoantorbital fenestrae [ 26 , 27 ]) is 2.57, an intermediate value when compared with Chinese tapejarids (ranging from 1.76 in “ Huaxiapterus jii ” [ 23 ] to 4.05 in S . lingyuanensis [ 7 , 28 ]). The rostral index (RI sensu [ 29 ]) of GP/2E 9266 is 0.46, differing from those of the holotype (SMNK PAL 2344) and a referred specimen (SMNK PAL 2343) of Tupa .…”

“…atavismus and Ta . wellnhoferi ; [ 6 , 7 ]). Two distal tarsals are present, with the left one longer (10.2 mm) than the right one (6.2 mm).…”

“…Most Brazilian tapejarids are known from isolate skulls or partial skeletons, with the exceptions of Caiuajara dobruskii and Tapejara wellnhoferi , from which several disarticulated specimens were recovered [ 5 , 6 ]. Up to now, the most complete tapejarid specimens were found in the Early Cretaceous of China [ 7 ], but their anatomy has not yet been described in detail.…”

Assessing ontogenetic maturity in extinct saurian reptiles

“…Haines, 1939; Maisano, 2002 c ; see Section IV.3 c ). The external surface texture of the proximal ends of long bones is the most common way postcranial ossification is used to assess maturity in our database, with ‘unfinished’ textures reported for ‘embryos’ (Motani, 1999 a ; Wang & Zhou, 2004; Motani et al ., 2014), ‘babies’ (Carpenter, 1994; Carpenter & McIntosh, 1994), ‘juveniles’ (Clarke, 2004; Codorniú & Chiappe, 2004; Evans et al ., 2005; Bennett, 2018; Zhang et al ., 2019; Farke & Yip, 2019), ‘subadults’ (Bolet & Evans, 2012; Hu, Zhong‐He & O'Connor, 2014; Dong et al ., 2019), and immature individuals (Bolet & Evans, 2010), and with mature or ‘adult’ individuals possessing finished or fully ossified epiphyses (e.g. Haines, 1942; Callison & Quimby, 1984; Worthy, 1989; Wiffen et al ., 1995; Cau et al ., 2014).…”

New Antarctic clawed lobster species (Crustacea: Decapoda: Nephropidae) from the Upper Cretaceous of James Ross Island

“…Antarctica plays a very important role in understanding faunal groups with Gondwanan origin (Crame 1989;Clarke et al 2004). However, on the account of the continent's inhospitable conditions, its remoteness and the high cost of operations, Antarctica's fossil record is generally scarce compared to deposits in other continents (e.g., Kellner 1996;Feldmann & Schweitzer 2017;Kellner et al 2019;Zhang et al 2019). The James Ross Basin, in the Antarctic Peninsula, has one of the best-preserved and highly diverse fossil assemblages of the continent (Feldmann 1990;Feldmann et al 1993).…”