Abstract The Wukongopteridae is an important pterosaur clade from the Yanliao Biota, combining features of basal and derived pterosaurs. So far, the Wukongopteridae consists of five species divided into three genera: Wukongopterus lii, Darwinopterus modularis, Darwinopterus linglongtaensis, Darwinopterus robustodens, and Kunpengopterus sinensis. Here we report a new species, Darwinopterus camposi sp. nov., based on an almost complete skeleton (IVPP V 17957). The new species is referred to Darwinopterus due to the presence of an elongated posterior region of the skull and the bony premaxillary crest that starts about the anterior margin of the nasoantorbital fenestra. It differs from all other wukongopterids by having the dorsal margin of the premaxillary crest straight, without an extensive dorsal projection and presenting a smooth lateral surface. Furthermore, D. camposi sp. nov. has eighteen and fourteen teeth on each side of the upper and lower jaws, respectively, and the fourth phalanx of the wing finger shorter than the first. IVPP V 17957 shows some fused postcranial bones, like the extensor tendon process to the first wing finger phalanx, but also has unfused premaxilla and frontal, which provides further information about wukongopterid ontogeny.

Abstract Shell beds, or coquinas, have a complex origin, limiting their utility in paleoecology. However, such accumulations can serve as crucial paleoenvironmental indicators, since their bioestratinomic and diagenetic properties explain the physical-chemical and biological processes of their formation, as well as the ancient environments linked to their development. In 2016, the PALEOANTAR Project sampled coquinas from the James Ross Island (Antarctic Peninsula) in Passo São José (PSJ – San José Way) and Muro do Castelo (MDC – Castle Wall), two new localities with outcrops of the lower Lachman Crags Member, Santa Marta Formation, Marambio Group, Cretaceous of Larsen Basin. The paleontological content and sedimentary structures indicate a shallow marine depositional system. The PSJ coquina are composed by gastropods bioclasts, with predominantly dense/loose packing. The MDC presents a larger variety of bioclasts with bivalve dominance on a loose packing and conglomeratic horizons, that varies from granule to pebble. Sedimentary and biostratinomic features observed in samples from both localities indicate their genesis from high-energy events, characterized as a proximal tempestite. These descriptions allow a more accurate reconstruction of the depositional environments, highlighting the importance of these rocks in the geological record during the Cretaceous of Antarctica.

Abstract This study investigates ichnoassemblages characterized by spreite trace fossils from the Upper Cretaceous Snow Hill Island Formation on Vega Island, Antarctica. The succession reveals alternating heterolithic beds of sandy siltstones to very fine- to fine-grained sandstones, suggestive of a deltaic depositional setting influenced by fluctuating energy conditions. The dominance of spreite structures, such as Paradictyodora antarctica and Euflabella, suggests the prevalence of a colonization window for deposit- or detritus-feeding activity. Notably, the prevalence of Euflabella towards the upper levels of the succession, in more proximal and impacted depositional setting, suggests an adaptive strategy for coping with varying food resources, corroborating its role as a trophic generalist. Additionally, the absence of distinct shifts between fully marine and stressed ichnofauna challenges a clear assignation to the Phycosiphon or Rosselia ichnofacies, although in vertical succession the Euflabella dominance in upper levels is related to a lower diverse ichnoassemblage than Paradictyodora in lower levels, suggesting some freshwater impact in the top. The occurrence of horizontal and vertical sessile deposit feeding structures would align with the Rosselia ichnofacies definition, but the presence of spreite burrows and high ichnodisparity better fits into the Cruziana ichnofacies. These spreite-dominated ichonoassemblages are here attributed to Cruziana ichnofacies.