Scrotifera
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| Scrotifera | ||||||||||||
| Waddell , Cao , Hauf & Hasegawa , 1999 |
The Scrotifera are a systematic taxon within the Laurasiatheria , one of the four main lines of the higher mammals (Eutheria). Besides the insectivores (Eulipotyphla) all other representatives of the Laurasiatheria belong to the Scrotifera . The taxon was introduced in 1999 by Peter J. Waddell and research colleagues on the basis of molecular genetic results which had shown that the common group of predators (Carnivora), originally derived on an anatomical basis, with the so-called " ungulates " (ungulata), consisting of unpaired ungulates (Perissodactyla), even-toed ungulates (Artiodactyla) and paenungulata who were united until then in the taxon Ferungulata, not monophyletic represent community.
Rather, the carnivores as well as the ungulate and odd-toed ungulates have a closer genetic relationship to the bats (Chiroptera) and the pangolins (Pholidota), whose exact relationship was previously considered difficult. Because of this, the taxon of the Ferungulata was dissolved and replaced by the new group Scrotifera in order to unite the five mentioned orders with one another. As a subordinate group, the Fereuungulata were established, which in addition to the pair and odd- toed ungulates ( Euungulata ) include the predators and pangolins ( Ferae ) and their sister group are the bats.
As a common feature of the scrotifera behind the true penis trained scrotum , have the adult males of the group and some aquatic representatives and at most, with the exception of pangolins is outwardly visible. With the exceptions mentioned, the testicles lie directly under the skin. The characteristic of the externally visible scrotum is considered to be the original characteristic of the group and was also the inspiration for the name of the taxon. Translated into German it means "scrotum carrier" (from Latin scrotum "scrotum" and ferre "to carry"). However, the characteristic also occurs in other higher mammals, such as primates , but is not to be understood as a basic characteristic there.
The following orders and groups that exist today can be added to the Scrotifera:
- Scrotifera Waddell, Cao, Hauf & Hasegawa , 1999
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- Order pangolins (Pholidota Weber , 1904)
- Order predators (Carnivora Bowdich , 1821)
- Order bats (Chiroptera Blumenbach , 1779)
- Order odd-toed ungulate (Perissodactyla Owen , 1848)
- Cetartiodactyla Montgelard, Catzeflis & Douzery , 1997
- Order Artiodactyla (Artiodactyla Owen , 1848)
- Order whales (Cetacea Brisson , 1762)
According to molecular genetic analyzes, the Scrotifera split off from the insectivores more than 77 million years ago in the Upper Cretaceous , but the oldest fossil records date back to the subsequent Paleocene and Lower Eocene .
Cladograms
An original cladogram for the internal systematics of the Laurasiatheria looked after Peter J. Waddell et al. 2001 looks like this:
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A more modern cladogram of the internal systematics of Laurasiatheria results from Maureen A. O'Leary et al. 2013:
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Individual evidence
- ↑ George Gaylord Simpson: The principles of classification and a classification of mammals. Bulletin of the American Museum of Natural History 85, 1945, pp. 1–350 (pp. 105–162) ( PDF )
- ↑ a b c d Peter J. Waddell, Ying Cao, Jöerg Hauf, Masami Hasegawa: 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), 1999, pp. 31-53 doi: 10.1080 / 106351599260427
- ^ Robert W. Meredith, Jan E. Janečka, John Gatesy, Oliver A. Ryder, Colleen A. Fisher, Emma C. Teeling, Alisha Goodbla, Eduardo Eizirik, Taiz LL Simão, Tanja Stadler, Daniel L. Rabosky, Rodney L. Honeycutt, John J. Flynn, Colleen M. Ingram, Cynthia Steiner, Tiffani L. Williams, Terence J. Robinson, Angela Burk-Herrick, Michael Westerman, Nadia A. Ayoub, Mark S. Springer, William J. Murphy: Impacts of the Cretaceous Terrestrial Revolution and KPg extinction on mammal diversification. Science 334 (6055), 2011, pp. 521-524 doi: 10.1126 / science.1211028
- ↑ a b Maureen A. O'Leary, Jonathan I. Bloch, John J. Flynn, Timothy J. Gaudin, Andres Giallombardo, Norberto P. Giannini, Suzann L. Goldberg, Brian P. Kraatz, Zhe-Xi Luo, Jin Meng , Xijun Ni, Michael J. Novacek, Fernando A. Perini, Zachary S. Randall, Guillermo W. Rougier, Eric J. Sargis, Mary T. Silcox, Nancy B. Simmons, Michelle Spaulding, Paúl M. Velazco, Marcelo Weksler, John R. Wible, Andrea L. Cirranello: The Placental Mammal Ancestor and the Post-K-Pg Radiation of Placentals. Science 339 (6120), 2013, pp. 662-667 doi: 10.1126 / science.1229237
- ↑ Peter J. Waddell, Hirohisa Kishino, Rissa Ota: A Phylogenetic Foundation for Comparative Mammalian Genomics. Genome Informatics 12, 2001, pp. 141-154 doi: 10.11234 / gi1990.12.141