Summary: Petrosal bones of placental mammals from
the Late Cretaceous of Uzbekistan
ERIC G. EKDALE, J. DAVID ARCHIBALD, and ALEXANDER O. AVERIANOV
Ekdale, E.G., Archibald, J.D., and Averianov, A.O. 2004. Petrosal bones of placental mammals from the Late Cretaceous
of Uzbekistan. Acta Palaeontologica Polonica 49 (1): 161176.
Petrosal bones representing "Zhelestidae" and Kulbeckia ("Zalambdalestidae") were recovered from the Late Cretaceous
of Uzbekistan and are formally described. The "zhelestid" petrosal retains several characters ancestral to eutherians (if not
more basally in the mammalian phylogeny), including a prootic canal, a lateral flange, and a less elliptical fenestra
vestibuli. The only other eutherian taxon to retain these structures is the Early Cretaceous Prokennalestes. No characters
unique to "zhelestids" and ungulates were found in the "zhelestid" petrosal. The petrosal of Kulbeckia shares several
characters in common with other "zalambdalestids" (such as Zalambdalestes and Barunlestes), as well as Asioryctes and
Kennalestes, including a curved ridge connecting the crista interfenestralis to the caudal tympanic process, and presence
of a "tympanic process" at the posterior aspect of the petrosal.
Key words: Mammalia, "Zhelestidae", "Zalambdalestidae", Kulbeckia, petrosal, Late Cretaceous, Uzbekistan.
Eric G. Ekdale [email@example.com], Department of Biology, San Diego State University, San Diego, California
92182-4614, USA. Present address: Department of Geological Sciences, The University of Texas, Austin, Texas
J. David Archibald [firstname.lastname@example.org], Department of Biology, San Diego State University, San Diego,
California 92182-4614, USA;
Alexander O. Averianov [sasha@AA1923.spb.edu], Zoological Institute, Russian Academy of Sciences, Universitetskaya