Pengornithidae

Pengornithidae is a group of early enantiornithines from the early Cretaceous Period of China. Specimens of these animals have been found both in the Huajiying Formation and Jiufotang Formation of Liaoning and Hebei provinces, dating from the Hauterivian age (130.7 million years ago) to the Aptian age (120 million years ago).[1]

Pengornithids Temporal range: Early Cretaceous, 130.7–120 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Fossil specimen of Parapengornis eurycaudatus
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Dinosauria
Clade:	Saurischia
Clade:	Theropoda
Clade:	†Enantiornithes
Family:	†Pengornithidae Wang et al., 2014
Type genus
†Pengornis Zhou, Clarke, & Zhang, 2008
Genera
†Eopengornis †Pengornis †Parapengornis †Chiappeavis

Description

Pengornithids were primitive 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 (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.[2]

Ecology

The unique, rounded pygostyle and long, stiff tail feathers of pengornithids would have made their tail overall similar to that of woodpeckers. 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 birds, they were better climbers than many other enantiornithes.[2]

Classification

The cladogram below was found in the phylogenetic analysis of Hu et al. 2014.[2]

Enantiornithes

Protopteryx       Elsornis         Rapaxavis     Iberomesornis       Shanweiniao     Longirostravis       Euenantiornithes       Boluochia     Longipteryx         Vescornis     Otogornis     Gobipteryx           Eocathayornis       Shenqiornis     Pengornithidae     Eopengornis     IVPP V18632         Parapengornis     Pengornis           Neuquenornis       Eoenantiornis         Liaoningornis     Eoalulavis         Concornis     Cathayornis

The cladogram below was found by an analysis by Wang et al. in 2015, updated from a previous data set created by Jingmai O'Connor.[3]

Ornithothoraces	Euornithes   †Enantiornithes   †Protopteryx     †Pengornithidae     †Longipterygidae   †Euenantiornithes   †Eocathayornis       †Elsornis       †Dunhuangia     †Fortunguavis       †Bohaiornithidae       †Pterygornis       †Eoenantiornis       †Cathayornis       †Vescornis     †Neuquenornis     †Gobipteryx     †Eoalulavis       †Qiliania     †Concornis

References

1. Wang, X.; O'Connor, J. K.; Zheng, X.; Wang, M.; Hu, H.; Zhou, Z. (2014). "Insights into the evolution of rachis dominated tail feathers from a new basal enantiornithine (Aves: Ornithothoraces)". Biological Journal of the Linnean Society. 113 (3): 805–819. doi:10.1111/bij.12313.
2. Hu, Han; o'Connor, Jingmai K.; Zhou, Zhonghe (2015). "A New Species of Pengornithidae (Aves: Enantiornithes) from the Lower Cretaceous of China Suggests a Specialized Scansorial Habitat Previously Unknown in Early Birds". PLOS ONE. 10 (6): e0126791. doi:10.1371/journal.pone.0126791. PMC 4454694. PMID 26039693.
3. Wang, Hu; Li (2015). "A new small enantiornithine bird from the Jehol Biota, with implications for early evolution of avian skull morphology". Journal of Systematic Palaeontology. 14 (6): 1–17. doi:10.1080/14772019.2015.1073801.