Akidolestes

Akidolestes
Temporal range: Early Cretaceous, 122 Ma
Skeleton
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Symmetrodonta
Family: Spalacotheriidae
Genus: Akidolestes
Li & Luo, 2006
Type species
Akidolestes cifellii
Li & Luo, 2006

Akidolestes is an extinct genus of mammals of the family Spalacotheriidae, a group of mammals related to therians (the subclass containing marsupials and placentals).

The genus name, Akidolestes, is derived from akido, Greek for point, and lestes, Greek for thief. Akido- refers to the pointed snout and -lestes is a common suffix for fossil mammals. The specific epithet, cifelli, is in honor of Richard L. Cifelli, a prominent researcher in prehistoric mammals.[1]

An Akidolestes fossil preserved with a complete post-cranium and a partial skull was discovered in the Yixian Formation of Liaoning, China.[2][1] The holotype of Akidolestes cifellii, reserved in the Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences,[2][1] has a complete skeleton with a partial skull and dentition.[2][1] It displays characteristics of monotremes but appears to be more related to modern therian mammals.[2]

Although it had some features similar to monotremes in the lumbar vertebrae, pelvis, and hindlimb, Akidolestes cifellii is still placed in the Spalacotheriidae family and close to Zhangheotherium and Maotherium.[1] Those convergent synapomorphies might derive from a shared early common ancestor.[1] Based on the analysis and comparison of anatomy and locomotory features of Akidolestes cifellii with its related taxa, there is a hypothesis that spalacotheroids might have evolved in Eurasia and then dispersed to North America, which is consistent with the geodispersal pattern common to several mammalian groups during the Early Cretaceous period.[1]

Most fossils of Mesozoic mammals exist as teeth or jaw fragments only. Akidolestes cifellii was the third spalacotheroid species discovered with a complete skeleton in the Yixian Formation, after Zhangheotherium and Maotherium.[2]

  1. ^ a b c d e f g Li, Gang; Luo, Zhe-Xi (2006-01-12). "A Cretaceous symmetrodont therian with some monotreme-like postcranial features". Nature. 439 (7073): 195–200. Bibcode:2006Natur.439..195L. doi:10.1038/nature04168. ISSN 1476-4687. PMID 16407951. S2CID 4427305.
  2. ^ a b c d e Chen, Meng; Luo, Zhe-Xi (2012-04-20). "Postcranial Skeleton of the Cretaceous Mammal Akidolestes cifellii and Its Locomotor Adaptations". Journal of Mammalian Evolution. 20 (3): 159–189. doi:10.1007/s10914-012-9199-9. ISSN 1064-7554. S2CID 14801592.