Scrotifera ("beasts with scrotum") is a clade of placental mammals that groups together grandorder Ferungulata, clade Apo-Chiroptera (aka order Chiroptera), other extinct members and their common ancestors. The clade Scrotifera is a sister group to the order Eulipotyphla (true insectivores) based on evidence from molecular phylogenetics,[1] and together they make superorder Laurasiatheria. The last common ancestor of Scrotifera is supposed to have diversified ca. 73.1[3] to 85.5[4] 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 (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.[1]
Classification and phylogeny
History of phylogeny
In year 2006 clade Pegasoferae (a clade of mammals that includes orders Chiroptera, Carnivora, Perissodactyla and Pholidota) was proposed as part of clade Scrotifera and sister group to the order Artiodactyla, based on genomic research in molecular systematics.[5] The monophyly of the group is not well supported, and recent studies have indicated that this clade is not a natural grouping.[4][6]
According to 2022 study of Matthew F. Jones, Nancy Simmons and K. Christopher Beard, two nyctitheres species (Eosoricodon terrigena and "Wyonycteris" microtis) were identified to be most closely related to bats.[7]
Taxonomy
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Clade: Scrotifera (Waddell, 1999)
Phylogeny
The phylogenetic relationships of clade Scrotifera are shown in the following cladogram, reconstructed from mitochondrial and nuclear DNA and protein characters, as well as the fossil record:[1][8][4][9][10][11]
Boreoeutheria Euarchontoglires 
Laurasiatheria Eulipotyphla 
Scrotifera Ferungulata †Pantodonta 
†Tillodontia
†Deltatheriidae
Pan-Euungulata 
Ferae 
? †Acmeodon
†Eosoricodontidae
†"Wyonycteris" microtis
Apo-Chiroptera Chiroptera 
? †"Icaronycteris" sigei
? †"Icaronycteris" menui
†Icaronycteridae
†Onychonycteridae 
†Archaeonycteridae
†Hassianycteridae
†Palaeochiropterygidae
See also
References
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^ a b c d Waddell, Peter J.; Cao, Ying; Hauf, Jöerg; Hasegawa, Masami (1 March 1999). Olmstead, R. (ed.). "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. ISSN 1076-836X. PMID 12078643.
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^ Springer M. S., Murphy W. J., Eizirik E., O'Brien S. J. In: "Placental Mammals: Origins and Relationships of the Major Clades." Rose K. D., Archibald J., editor. Baltimore: Johns Hopkins; (2005.) "Molecular evidence for major placental clades"; pp. 37–49
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^ dos Reis, Mario; Inoue, Jun; Hasegawa, Masami; Asher, Robert J.; Donoghue, Philip C. J.; Yang, Ziheng (7 September 2012). "Phylogenomic datasets provide both precision and accuracy in estimating the timescale of placental mammal phylogeny". Proceedings of the Royal Society B: Biological Sciences. 279 (1742): 3491–3500. doi:10.1098/rspb.2012.0683. ISSN 0962-8452. PMC 3396900. PMID 22628470.
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^ a b c Zhou, Xuming; Xu, Shixia; Xu, Junxiao; Chen, Bingyao; Zhou, Kaiya; Yang, Guang (1 January 2012). "Phylogenomic Analysis Resolves the Interordinal Relationships and Rapid Diversification of the Laurasiatherian Mammals". Systematic Biology. 61 (1): 150–64. doi:10.1093/sysbio/syr089. ISSN 1063-5157. PMC 3243735. PMID 21900649.
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^ Nishihara, H.; Hasegawa, M.; Okada, N. (2006). "Pegasoferae, an unexpected mammalian clade revealed by tracking ancient retroposon insertions". Proceedings of the National Academy of Sciences. 103 (26): 9929–9934. doi:10.1073/pnas.0603797103. PMC 1479866. PMID 16785431.
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^ Tsagkogeorga, G.; Parker, J.; Stupka, E.; Cotton, J. A.; Rossiter, S. J. (2013). "Phylogenomic analyses elucidate the evolutionary relationships of bats (Chiroptera)". Current Biology. 23 (22): 2262–2267. doi:10.1016/j.cub.2013.09.014. PMID 24184098.
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^ Matthew F. Jones, Nancy Simmons, K. Christopher Beard (2022.) "Relationship of nyctitheres (Mammalia, Nyctitheriidae) to bats and other laurasiatherians", in "The Society of Vertebrate Paleontology 82nd annual meeting"
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^ Peter J. Waddell, Hirohisa Kishino, Rissa Ota (2001.) "A Phylogenetic Foundation for Comparative Mammalian Genomics" Genome Informatics 12: 141–154
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^ O’Leary, M. A., Bloch JI, Flynn, J. J., Gaudin, T. J., Giallombardo, A., Giannini, N. P., Goldber, S. L, Kraatz, B. P., Luo, Z-X, Jin Meng, Xijun Ni, Novacek, M. J., Perini, F. A., Randall, Z. S., Rougier, G. W., Sargis, E. J., Silcox, M. T., Simmons, N. B., Spaulding, M. Velazco, P. M., Weksler, M., Wible, J. R. Cirranello, A. L. (2013.) "The Placental Mammal Ancestor and the Post–K-Pg Radiation of Placentals." Science 339:6120:662-667.
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^ Frank Zachos (2020.) "Mammalian Phylogenetics: A Short Overview of Recent Advances", In book: "Mammals of Europe – Past, Present, and Future" (pp.31-48)
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^ Xue Lv, Jingyang Hu, Yiwen Hu, Yitian Li, Dongming Xu, Oliver A. Ryder, David M. Irwin, Li Yu (2021.) "Diverse phylogenomic datasets uncover a concordant scenario of laurasiatherian interordinal relationships", Molecular Phylogenetics and Evolution, Volume 157
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