A new species from an ornithuromorph (Aves: Ornithothoraces) dominated locality of the Jehol Biota

Insight into the growth pattern and bone fusion of basal birds from an Early Cretaceous enantiornithine bird

“…It appears that the unfused pelvis in adult individuals of Early Cretaceous birds is plesiomorphically inherited from their dinosaurian ancestors and that pelvic fusion evolved convergently in late history of the Enantiornithes and Ornithuromorpha. Early Cretaceous ornithuromorphs generally exhibited a relatively higher degree of bone fusion than contemporaneous enantiornithines (21). For example, the tarsometatarsus is unfused distally in enantiornithines (1, 2) but completely fused in most ornithuromorphs except the most basal ornithuromorph Archaeorhynchus (34).…”

A new Early Cretaceous enantiornithine (Aves, Ornithothoraces) from northwestern China with elaborate tail ornamentation

“…In contrast, several Jehol ornithuromorphs (e.g., Hongshanornis longicresta Zhou and Zhang, 2005, Piscivoravis lii Zhou et al, 2013, Yanornis martini Zhou and Zhang, 2001Zhou and Zhang, 2005;Clarke et al, 2006;Zhou et al, 2013) preserve large, round tails formed by a fan of 6-10 rectrices, and one taxon (Schizooura lii) has a forked tail (Zhou et al, 2012), all considered aerodynamic morphologies. The only exception is the holotype of the recently discovered ornithuromorph Iteravis huchzermeyeri Zhou et al, 2014, which preserves what appears to be a pair of short, ornamental rectrices . With the possible exception of those preserved in the holotype specimen of Shanweiniao cooperorum, all preserved enantiornithine rectricial morphologies are interpreted as having ornamental functions, strongly suggesting that sexual selection was a major driving force in shaping tail morphologies within the clade (Wang et al, 2014b).…”

A new basal ornithuromorph bird (Aves: Ornithothoraces) from the Early Cretaceous of China with implication for morphology of early Ornithuromorpha

“…). Both vertebrae are exposed in left lateral view, revealing that the lateral surfaces of the centra are nearly flat, without the broad and deep fossa reported in other basal ornithuromorphs, e.g., Jianchangornis , Schizooura , and Iteravis (Zhou, Zhang & Li, ; Zhou et al ., , ). Visible from the cranial one of the two vertebrae, the parapophysis is cranially located as in other ornithuromorphs (Chiappe, ; Zhou et al ., ), rather than centrally located as in enantiornithines (Chiappe & Walker, ); the spinous process is well developed, approaching the height of the centrum; the postzygapophysis projects caudally beyond the centrum by a distance that is about half the centrum length, considerably longer than in Jianchangornis , Iteravis , and Patagopteryx (Chiappe, ; Zhou et al ., , ).…”

“…nov. ( IVPP ) with selected basal ornithuromorphs. (A) Bellulia rectusunguis ; (B) Archaeorhynchus spathula (modified from Z hou et al ., ); (C) Jianchangornis microdonta ; (D) Jiuquanornis niui ; (E) Hongshanornis longicresta (modified from Z hou et al ., ); (F) Yixianornis grabaui (modified from Z hou et al ., ); (G) Gansus yumenensis ; (H) Piscivoravis lii (modified from Z hou et al ., ); (I) Iteravis huchzermeyeri (modified from Z hou et al ., ); and (J) Yanornis martini (modified from Z hou et al ., ). Line drawings are not scaled.…”

“…Here we describe a new basal ornithuromorph bird from the Jiufotang Formation. The new specimen has a V‐shaped furcula with a short hypocleidium, a feature otherwise known only in Schizooura among Mesozoic ornithuromorphs, in which the furcula is typically delicate and U‐shaped (Zhou & Zhang, ; O'Connor, Gao & Chiappe, ; Zhou, Zhou & O'Connor, ; Zhou, O'Connor & Wang, ). A suit of primitive features hint a basal position for this new taxon, which is corroborated by our phylogenetic analysis.…”