Pengornithidae is a group of early

enantiornithines The Enantiornithes, also known as enantiornithines or enantiornitheans in literature, are a group of extinct avialans ("birds" in the broad sense), the most abundant and diverse group known from the Mesozoic era. Almost all retained teeth and cl ...

from the early

Cretaceous Period The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 77.1 million years, it is the ninth and longest geologi ...

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

, with the putative member '' Falcatakely'' possibly extending this clade's range into the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...

Madagascar Madagascar, officially the Republic of Madagascar, is an island country that includes the island of Madagascar and numerous smaller peripheral islands. Lying off the southeastern coast of Africa, it is the world's List of islands by area, f ...

, and several putative pengornithids also hail from this formation.O'Connor and Forster, 2010. A Late Cretaceous (Maastrichtian) avifauna from the Maevarano Formation, Madagascar. Journal of Vertebrate Paleontology. 30(4), 1178-1201. Specimens of these animals have been found both in the

Huajiying Formation The Huajiying Formation is a geological formation in Hebei, People's Republic of China. Known for its fossils including feathered dinosaurs, the age of the formation is uncertain. It may represent an early portion of the Jehol Biota, dating to som ...

and

Jiufotang Formation The Jiufotang Formation () is an Early Cretaceous geological formation in Chaoyang, Liaoning which has yielded fossils of feathered dinosaurs, primitive birds, pterosaurs, and other organisms (see Jehol Biota). It is a member of the Jehol group. T ...

Liaoning ) , image_skyline = , image_alt = , image_caption = Clockwise: Mukden Palace in Shenyang, Xinghai Square in Dalian, Dalian coast, Yalu River at Dandong , image_map = Liaoning in China (+all claims hatched).svg , ...

and

Hebei Hebei is a Provinces of China, province in North China. It is China's List of Chinese administrative divisions by population, sixth-most populous province, with a population of over 75 million people. Shijiazhuang is the capital city. It bor ...

provinces, dating from the

Hauterivian The Hauterivian is, in the geologic timescale, an age in the Early Cretaceous Epoch or a stage in the Lower Cretaceous Series. It spans the time between 132.6 ± 2 Ma and 125.77 (million years ago). The Hauterivian is preceded by the Valangi ...

age (130.7 million years ago) to the

Aptian The Aptian is an age (geology), age in the geologic timescale or a stage (stratigraphy), stage in the stratigraphic column. It is a subdivision of the Early Cretaceous, Early or Lower Cretaceous epoch (geology), Epoch or series (stratigraphy), S ...

age (120 million years ago).

Description

Pengornithids were basal enantiornithes. They had many small teeth in their jaws, and stout legs. Their internal anatomy was characterized by a hooked outgrowth of the shoulder blade and a

pygostyle Pygostyle is a skeletal condition in which the final few caudal vertebrae are fused into a single ossification, supporting the tail feathers and musculature. In modern birds, the rectrices attach to these. The pygostyle is the main component o ...

(the tail bone to which long feathers attach) which was short and rounded, instead of long and blade-shaped as in other enantiornithes. While most enantiornithes had four long backward projections growing from their breastbones, pengornithids only had two. Assuming ''Falcatakely'' is a pengornithid, it exhibits a rather novel cranial morphology compared to other enantiornitheans, having a

toucan Toucans (, ) are Neotropical birds in the family Ramphastidae. They are most closely related to the Semnornis, Toucan barbets. They are brightly marked and have large, often colorful Beak, bills. The family includes five genus, genera and over ...

-like snout ending on small teeth.

Ecology

The unique, rounded pygostyle and long, stiff tail feathers of pengornithids would have made their tail overall similar to that of

woodpecker Woodpeckers are part of the bird family (biology), family Picidae, which also includes the piculets, wrynecks and sapsuckers. Members of this family are found worldwide, except for Australia, New Guinea, New Zealand, Madagascar and the extreme ...

s. The feet of pengornithids were also particularly adapted for grasping branches. These features indicate that while pengornithids may not have been as adept at climbing as many modern

bird Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...

s, they were better climbers than many other enantiornithes. ''Falcatakely'' has been compared to

toucans Toucans (, ) are Neotropical birds in the family Ramphastidae. They are most closely related to the Toucan barbets. They are brightly marked and have large, often colorful bills. The family includes five genera and over 40 different species. ...

due to similar snout morphology.

Classification

The

cladogram A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not s ...

below was found in the phylogenetic analysis of Hu ''et al.'' 2014. The

below was found by an analysis by Wang ''et al.'' in 2015, updated from a previous data set created by Jingmai O'Connor.

References

{{Taxonbar, from=Q20072368 Enantiornithes Dinosaur families Early Cretaceous dinosaurs Dinosaurs of China