Bohaiornithidae

Bohaiornithidae is a group of early enantiornithean stem-birds from the early Cretaceous Period of China. All undisputed Bohaiornithidae specimens come from the northeast of present-day China – specifically, the eastern and southern foothills of the Greater Khingan mountains –, and date to the early Aptian age, roughly 125–120 million years ago. As of 2024 they are not certainly known from outside this limited region and timeframe, even though there and then they were a prominent – and probably predatory, unlike the bulk of their relatives – element of the local fauna, namely the Jehol Biota. The taxon Bohaiornithidae was established by Wang and colleagues in 2014. They defined it as the natural group formed by all descendants of the common ancestor of the type species, Bohaiornis guoi, and Shenqiornis mengi.

Description

Most adult bohaiornithids would have been rather similar in size and appearance to each other, and the family lacked the longevity and physical diversity of some other enantiornithean groups, such as the long-snouted longipterygids. The largest specimens of bohaiornithids assumed to have reached adulthood, namely the holotype of Zhouornis and a referred specimen of Bohaiornis, were about the size of a pigeon, which is much larger than most other Jehol enantiornitheans with the exception of Pengornis and Xiangornis. The smallest and youngest bohaiornithid specimens were about half the size of the largest ones.

Similar to most enantiornitheans, bohaiornithids possessed teeth rather than a beak as in modern birds, although they could be distinguished from their relatives due to the structure of their teeth. Bohaiornithid teeth were large, robust and somewhat conical, but had sharply pointed tips which curved backwards.