Scrotifera

Scrotifera; Temporal range: Paleocene–Recent PreꞒ Ꞓ O S D C P T J K Pg N
	From top to right: tiger, Indian pangolin, red deer, white rhino and Lyle's flying fox. Representing the living orders: Carnivora, Pholidota, Artiodactyla, Perissodactyla and Chiroptera, comprising Scrotifera.
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Superorder:	Laurasiatheria
Clade:	Scrotifera; Waddell et al., 1999
Subgroups
	Grandorder: Ferungulata; Clade: Chiroptera; Family: †Eosoricodontidae; Genus: †Acmeodon; Genus: †Gelastops; Incertae sedis: †"Wyonycteris" microtis; ;
Synonyms
	Variamana (Springer, 2005);

Scrotifera ("scrotum bearers") is a clade of placental mammals that groups together grandorder Ferungulata, Chiroptera (bats), 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 2006, the clade Pegasoferae (a clade of mammals that includes orders Chiroptera, Carnivora, Perissodactyla and Pholidota) was proposed as part of the clade Scrotifera and a 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 a 2022 study, two extinct species (Eosoricodon terrigena and "Wyonycteris" microtis) were identified as outside of the family Nyctitheriidae and more closely related mammals to bats.^[7] In another 2022 study, the extinct genus Acmeodon was recognized as not a member of the extinct order Cimolesta but a basal laurasiatherian mammal in the clade Scrotifera.^[8]^[9]

Taxonomy

Former classification:	Current classification:
Clade: Scrotifera (Waddell, 1999) Order: Artiodactyla (Owen, 1848) (even-toed ungulate) Clade: Pegasoferae (Nishihara, 2006) Order: Chiroptera (Blumenbach, 1779) (bats) Clade: Zooamata (Waddell, 1999) Miroder: Ferae (Linnaeus, 1758) Order: Perissodactyla (Owen, 1848) (odd-toed ungulate)	Clade: Scrotifera (Waddell, 1999) Grandorder: Ferungulata (Simpson, 1945) Clade: Chiroptera (bats) Family: †Eosoricodontidae (Lopatin, 2005) Genus: †Acmeodon (Matthew & Granger, 1921) Genus: †Gelastops (Simpson, 1935) Incertae sedis: †"Wyonycteris" microtis (Secord, 2008)

References

^ ^a ^b ^c 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.
^ 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
^ 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.
^ ^a ^b 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.
^ 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.
^ 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.
^ 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"
^ Bertrand, O. C.; Shelley, S. L.; Williamson, T. E.; Wible, J. R.; Chester, S. G. B.; Flynn, J. J.; Holbrook, L. T.; Lyson, T. R.; Meng, J.; Miller, I. M.; Püschel, H. P.; Smith, T.; Spaulding, M.; Tseng, Z. J.; Brusatte, S. L. (2022). "Brawn before brains in placental mammals after the end-Cretaceous extinction". Science. 376 (6588): 80–85. Bibcode:2022Sci...376...80B. doi:10.1126/science.abl5584. hdl:20.500.11820/d7fb8c6e-886e-4c1d-9977-0cd6406fda20.
^ Bertrand, O. C.; Jiménez Lao, M.; Shelley, S. L.; Wible, J. R.; Williamson, T. E.; Meng, J.; Brusatte, S. L. (2023). "The virtual brain endocast of Trogosus (Mammalia, Tillodontia) and its relevance in understanding the extinction of archaic placental mammals" (PDF). Journal of Anatomy. doi:10.1111/joa.13951. PMID 37720992. S2CID 262047180.

[Waddell1999-1] 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.

[2] 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

[dosReis2012-3] s 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.

[Zhou2012-4] 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.

[5] 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.

[6] 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.

[7] 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"

[8] Bertrand, O. C.; Shelley, S. L.; Williamson, T. E.; Wible, J. R.; Chester, S. G. B.; Flynn, J. J.; Holbrook, L. T.; Lyson, T. R.; Meng, J.; Miller, I. M.; Püschel, H. P.; Smith, T.; Spaulding, M.; Tseng, Z. J.; Brusatte, S. L. (2022). "Brawn before brains in placental mammals after the end-Cretaceous extinction". Science. 376 (6588): 80–85. Bibcode:2022Sci...376...80B. doi:10.1126/science.abl5584. hdl:20.500.11820/d7fb8c6e-886e-4c1d-9977-0cd6406fda20.

[9] Bertrand, O. C.; Jiménez Lao, M.; Shelley, S. L.; Wible, J. R.; Williamson, T. E.; Meng, J.; Brusatte, S. L. (2023). "The virtual brain endocast of Trogosus (Mammalia, Tillodontia) and its relevance in understanding the extinction of archaic placental mammals" (PDF). Journal of Anatomy. doi:10.1111/joa.13951. PMID 37720992. S2CID 262047180.

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