Explorornis

Taxobox
name = "Explorornis"
status = fossil
fossil_range = Late Cretaceous (Turonian)
regnum = Animalia
phylum = Chordata
classis = Aves
subclassis = Enantiornithes?
superordo = Euenantiornithes?
genus = "Explorornis"
genus_authority = Panteleev, 1998
subdivision_ranks = Species
subdivision =
*"Explorornis nessovi" Panteleev, 1998 (type)
*"Explorornis walkeri"
(Nessov and Panteleev, 1993) (disputed)and see text

"Explorornis" is a genus of Mesozoic birds. It lived during the mid-late Turonian stage, around 90 million years agoVerify source|date=October 2007 . Unlinke many contemporary genera, which are only known from a handful of remains that cannot be compared among each other, "Explorornis" is known from a handful of coracoids which are similar enough to be at least preliminarily assigned to a single genus. Nonetheless, each of the named species as well as the 2 unnamed ones are known by a single, damaged bone. They are all from the Bissekty Formation of the Kyzyl Kum, in present-day Uzbekistan.

"Explorornis" means simply "discovered bird", from Latin "explōrō" "to discover" and Ancient Greek "ornis" ("όρνις") "bird". The named species are honoring famous paleontologists: Lev Alexandrovich Nessov (1947–1995) and Cyril Alexander Walker.

"E. walkeri" (specimen PO 4825) was originally placed in "Enantiornis", because at the time of its description very little was known about Enantiornithes diversity. With the description of the type species "E. nessovi" (PO 4819), it became clear that "E. walkeri" was much closer to that bird than to the South American "Enantiornis", which also makes far more sense considering biogeography.

The unnamed specimens are distinct from these but each resembles one named species more than the other; PO 4818 seems closer to "E. nessovi" but is stouter than that bone, while PO 4817 appears more similar to "E. walkeri".

These were all smallish birds, maybe 15-20 cm long in life, except "E. walkeri" which was probably more than 25 cm long. [Mortimer (2004)]

Since only the coracoids are known, the phylogenetic position of these taxa is somewhat unresolved. They do resemble the more advanced Enantiornithes more than they do any other bird however. Confirmation of their placement with Euenantiornithes wuld still require more material however.

In addition, "E. walkeri" and PO 4817 seem to be more apomorphic than the other two bones, judging from the little data available. The former have some similarities to taxa such as "Gurilynia", "Halimornis", "Incolornis" and "Largirostrornis", and this might indicate that they do belong to a different as of yet unnamed genus after all.

Footnotes

References

* (2004): The Theropod Database: [http://home.comcast.net/~eoraptor/Phylogeny%20of%20Taxa.html Phylogeny of taxa] . Retrieved 2008-AUG-14.

External links

* Dinosauricon: [http://dino.lm.com/images/display.php?id=1151 Specimen drawing] (bottom left corner: "E. walkeri". Bottom row, third from the right: "E. nessovi") by Michael Mortimer. Retrieved 2007-OCT-29.