Apsaravis

Apsaravis is a Mesozoic avialan genus from the Late Cretaceous. The single known species, Apsaravis ukhaana, lived about 78 million years ago, in the Campanian age of the Cretaceous period. Its fossilized remains were found in the Camel's Humps sublocality of the Djadokhta Formation, at Ukhaa Tolgod in the Gobi Desert of Mongolia. They were collected in the 1998 field season by the Mongolian Academy of Sciences/American Museum of Natural History Paleontological Expeditions. It was described by Norell and Clarke (2001). Its habitat was presumably very arid open landscape much like it is today, perhaps hotter still and with more (but nonetheless intermittent) rain. Permanent freshwater would have been scarce.

Apsaravis is a Mesozoic avialan genus from the Late Cretaceous. The single known species, Apsaravis ukhaana, lived about 78 million years ago, in the Campanian age of the Cretaceous period. Its fossilized remains were found in the Camel's Humps sublocality of the Djadokhta Formation, at Ukhaa Tolgod in the Gobi Desert of Mongolia. They were collected in the 1998 field season by the Mongolian Academy of Sciences/American Museum of Natural History Paleontological Expeditions. It was described by Norell and Clarke (2001). Its habitat was presumably very arid open landscape much like it is today, perhaps hotter still and with more (but nonetheless intermittent) rain. Permanent freshwater would have been scarce. ==Implications== Apsaravis is important in avian paleontology. It has provided evidence that is directly relevant to at least four issues: ===Enantiornithine monophyly=== In their cladistic analyses, Clarke and Norell (2002) found that Apsaravis had a mixture of primitive and advanced characters (described above in "Sauriurae") that removed most of the supporting characters for the clade Enantiornithes. Twenty-seven characters have been used to support enantiornithine monophyly, but Apsaravis brings the number down to only four. The discovery of further basal ornithurine fossils like Apsaravis could render the Enantiornithes paraphyletic. This would mean that, rather than a radiation of primitive birds separate from the radiation that led to modern birds, "enantiornithines" would actually be steps along the way to becoming modern birds. ==Phylogenetic position== Clarke and Norell (2002) found that Apsaravis is the most basal ornithurine bird, but more advanced than Enantiornithes and Patagopteryx. Subsequent cladistic analysis indicates that it and the more advanced Palintropus – long believed to be a modern bird –, and perhaps Ambiortus with which the preceding two had occasionally been allied, form a distinct lineage. This has been named "Palintropiformes", but Apsaraviformes was proposed earlier for the Apsaravis lineage and is thus the senior synonym. And if this group is held to include Apatornis too, it would receive the name Ambiortiformes, which was proposed even earlier. ==Footnotes== ==References== (2004): The Theropod Database: Phylogeny of taxa. Retrieved 2013-MAR-02.

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