Meniscoessus Robustus
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''Meniscoessus'' is a
genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
of
extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...
multituberculates from the Upper
Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...
Period that lived in
North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...
. It is a member of the order Multituberculata, belonging to the suborder
Cimolodonta Cimolodonta is a clade of Multituberculata, multituberculate mammals that lived from the Cretaceous to the Eocene. They probably lived something of a rodent-like existence until their ecological niche was assumed by true rodents. The more basal ...
and
family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...
Cimolomyidae. The multituberculates were primitive, rodent-like mammals occupying the modern rodent ecological niche. They were significant for having diverged early in mammalian evolution, co-existing with dinosaurs for ~100 million years, surviving through the
Cretaceous–Paleogene extinction event The Cretaceous–Paleogene (K–Pg) extinction event, also known as the K–T extinction, was the extinction event, mass extinction of three-quarters of the plant and animal species on Earth approximately 66 million years ago. The event cau ...
and lasting until the end of the Paleogene, likely having been replaced by true rodents. ''Meniscoessus'' lived during the
Santonian The Santonian is an age in the geologic timescale or a chronostratigraphic stage. It is a subdivision of the Late Cretaceous Epoch or Upper Cretaceous Series. It spans the time between 86.3 ± 0.7 mya ( million years ago) and 83.6 ± 0.7 m ...
,
Campanian The Campanian is the fifth of six ages of the Late Cretaceous epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campa ...
and
Maastrichtian The Maastrichtian ( ) is, in the International Commission on Stratigraphy (ICS) geologic timescale, the latest age (geology), age (uppermost stage (stratigraphy), stage) of the Late Cretaceous epoch (geology), Epoch or Upper Cretaceous series (s ...
ages of the
Upper Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cret ...
. This was a period of significant diversification of multiturbiculates, and evidence that contradicts the popular misconception that mammals were unable to thrive due to being outcompeted by the dinosaurs. They are useful as index fossils for the Judithian, Edmontonian, and Lancian faunal stages. Like most early mammals, ''Meniscoessus'' fossils mainly consist of teeth.
Zofia Kielan-Jaworowska Zofia Emilia Kielan-Jaworowska (25 April 1925 – 13 March 2015) was a Polish paleobiologist. In the mid-1960s, she led a series of Polish-Mongolian paleontological expeditions to the Gobi Desert. She was the first woman to serve on the executi ...
and Jørn Hurum considered them to be the "best known" members of the Cimolomyidae.


Taxonomy


History

The genus ''Meniscoessus'' was named by
Edward Drinker Cope Edward Drinker Cope (July 28, 1840 – April 12, 1897) was an American zoologist, paleontology, paleontologist, comparative anatomy, comparative anatomist, herpetology, herpetologist, and ichthyology, ichthyologist. Born to a wealthy Quaker fam ...
in 1882. Members of this genus have been previously classified under the following genus names: '' Cimolomys '' (partly); ''Dipriodon''; ''Halodon''; ''Oracodon''; ''Moeniscoessus''; ''Selenacodon'' (partly); and ''Tripriodon''. As Osborn pointed out in 1891, a number of erroneous discoveries had been made as a result of analyzing different teeth of the same animal, different individuals of the same species, and violating the principle of priority due to workers ignoring previously published discoveries. There may have been confusion with some teeth described as belonging to small
carnivorous A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose nutrition and energy requirements are met by consumption of animal tissues (mainly mu ...
dinosaurs. These were further christened ''Dipriodon'', ''Tripriodon,'' and others, including ''Triprotodon''. Close similarities were then noticed with an already established dinosaur genus, '' Paronychodon'' (Cope 1876), also based on teeth from the Laramie Formation. Over time, an impressive school of names was synonymized under ''P.'' However, this is now considered a ''
nomen dubium In binomial nomenclature, a ''nomen dubium'' (Latin for "doubtful name", plural ''nomina dubia'') is a scientific name that is of unknown or doubtful application. Zoology In case of a ''nomen dubium,'' it may be impossible to determine whether a ...
''.


Species

* ''Meniscoessus collomensis'' – Named by Jason A. Lillegraven in 1987. Fossil remains were first found in Upper Cretaceous
strata In geology and related fields, a stratum (: strata) is a layer of Rock (geology), rock or sediment characterized by certain Lithology, lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by v ...
of the Williams Fork Formation in
Colorado Colorado is a U.S. state, state in the Western United States. It is one of the Mountain states, sharing the Four Corners region with Arizona, New Mexico, and Utah. It is also bordered by Wyoming to the north, Nebraska to the northeast, Kansas ...
. It appears useful as an index fossil for the Edmontonian faunal stage. It weighed an estimated . * ''Meniscoessus conquistus'' – Named by
Edward Drinker Cope Edward Drinker Cope (July 28, 1840 – April 12, 1897) was an American zoologist, paleontology, paleontologist, comparative anatomy, comparative anatomist, herpetology, herpetologist, and ichthyology, ichthyologist. Born to a wealthy Quaker fam ...
in 1882. Remains were found in Maastrichtian strata of Colorado and St. Mary River Formation of Canada. Cope thought it "was about the size of the Australian bandicoot." ''M.conquistus'' is the
type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...
of the genus ''Meniscoessus''. * ''Meniscoessus ferox'' – Named by Richard C. Fox in 1971. Remains were found in Campanian strata of the Upper Milk River Formation of
Alberta Alberta is a Provinces and territories of Canada, province in Canada. It is a part of Western Canada and is one of the three Canadian Prairies, prairie provinces. Alberta is bordered by British Columbia to its west, Saskatchewan to its east, t ...
, Canada. The
holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...
, collected in 1968, is in the
University of Alberta The University of Alberta (also known as U of A or UAlberta, ) is a public research university located in Edmonton, Alberta, Canada. It was founded in 1908 by Alexander Cameron Rutherford, the first premier of Alberta, and Henry Marshall Tory, t ...
collection. * ''Meniscoessus intermedius'' – Named by Richard C. Fox in 1976. Remains were first found in Campanian and Maastrichtian strata of the Oldman Formation of Alberta and
New Mexico New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...
,
Utah Utah is a landlocked state in the Mountain states, Mountain West subregion of the Western United States. It is one of the Four Corners states, sharing a border with Arizona, Colorado, and New Mexico. It also borders Wyoming to the northea ...
, and
Wyoming Wyoming ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States, Western United States. It borders Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho t ...
. It is estimated to have weighed about , as much as a large rat. They are the oldest member of the genus; their first appearance in the fossil record was 86 Million Years ago, during the Santonian age. * ''Meniscoessus major'' – Named by Loris Shano Russell in the 1930s. It is also known as ''Cimolomys major'' (Russell 1936). Fossils of this species have been found in Campanian and Maastrichtian aged strata, from 79-69 Million years ago. The body mass of this species is estimated at . The
holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...
is in Alberta. * ''Meniscoessus robustus'' – Named by Othniel Charles Marsh in 1889. Fossils have been found from Campanian to Maastrichtian strata of Wyoming, Montana,
South Dakota South Dakota (; Sioux language, Sioux: , ) is a U.S. state, state in the West North Central states, North Central region of the United States. It is also part of the Great Plains. South Dakota is named after the Dakota people, Dakota Sioux ...
and Alberta. There are controversial examples from one site in Alberta that may either be late Cretaceous(Lancian faunal stage) or early Paleocene( Puercan). Marsh thought that these organisms ranged from "rat" to "squirrel" to "rabbit" in size when they had lived. The weight of this species has been more recently estimated to be about . Marsh claimed discoveries of several new taxa in his 1889 work, but Osborn believed that many were synonymous with what is now ''M. robustus''. * ''Meniscoessus seminoensis'' – Named by Jaelyn J. Eberle and Jason A. Lillegraven in 1998. Remains were found in the Lancian faunal stage of the Maastrichtian strata of the Ferris Formation in Wyoming. A lower jaw fragment was found near the Seminoe Mountains, for which the species was named. It has a close resemblance to ''M. robustus'', with the new species distinguished by its characteristic 4th premolar (P4). It was estimated to have a body mass of Wilson et al, 2012, Supplemental Table 5 Several other names have been in circulation, such as ''Meniscoessus bustus'', and ''Meniscoessus coelatus''. The first is probably a variant of ''M. robustus'', while the latter seems to have been connected with
dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...
teeth.


Notes


References

* * * * * * * * * * * * * * * * * {{Taxonbar, from=Q12901024 Cimolodonta Cretaceous mammals Extinct mammals of North America Hell Creek fauna Laramie Formation Milk River Formation Fossil taxa described in 1882 Taxa named by Edward Drinker Cope Prehistoric mammal genera Santonian genus first appearances Campanian genera Maastrichtian genus extinctions