Scrotifera is a clade of placental mammals that comprises the following orders and their common ancestors: Chiroptera, Carnivora, Pholidota, Perissodactyla and Cetartiodactyla, with the latter including the traditional orders Artiodactyla and Cetacea. Scrotifera is the sister group to the Eulipotyphla and together they make up the Laurasiatheria.
Peter Waddell, then of the Institute of Statistical Mathematics, explains the etymology of the clade's name as follows:
The name comes from the word scrotum, a pouch in which the testes permanently reside in the adult male. All members of the group have a postpenile scrotum, often prominently displayed, except for some aquatic forms and pangolin (which has the testes just below the skin). It appears to be an ancestral character for this group, yet other orders generally lack this as an ancestral feature, with the probable exception of Primates.
The clade Scrotifera is based on evidence from molecular phylogenetics. The monophyly of the group is well supported, but there is some debate about the internal order, with Pegasoferae being an alternative to that shown in the following cladogram.
|Order-level cladogram of the Scrotifera in the context of the Boreoeutheria phylogeny.|
|The cladogram has been reconstructed from mitochondrial and nuclear DNA and protein characters.|
- Waddell; et al. (1999). "Using Novel Phylogenetic Methods to Evaluate Mammalian mtDNA, Including Amino Acid-Invariant Sites-LogDet plus Site Stripping, to Detect Internal Conflicts in the Data, with Special Reference to the Positions of Hedgehog, Armadillo, and Elephant". Systematic Biology. 48 (1): 31–53. doi:10.1080/106351599260427. Retrieved 4 October 2011.
- Zhou, X.; et al. (2011). "Phylogenomic analysis resolves the interordinal relationships and rapid diversification of the Laurasiatherian mammals". Systematic Biology. 61 (1): 150–64. doi:10.1093/sysbio/syr089. PMC 3243735. PMID 21900649. Retrieved 3 October 2011. (Advance Access; published online 7 September 2011) "Our reconstructions resolve the interordinal relationships within Laurasiatheria and corroborate the clades Scrotifera, Fereungulata, and Cetartiodactyla."
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