Scrotifera


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. The last common ancestor of Scrotifera is supposed to have diversified ca. 73.1 to 85.5 million years ago.

Etymology

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. 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.

Phylogeny

The clade Scrotifera is based on evidence from molecular phylogenetics. The monophyly of the group is well supported, although recent studies have indicated that the Pegasoferae is not a natural grouping.

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