''Chulsanbaatar'' is an extinct
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
mammal
A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...
from the
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 ...
of
Mongolia
Mongolia is a landlocked country in East Asia, bordered by Russia to the north and China to the south and southeast. It covers an area of , with a population of 3.5 million, making it the world's List of countries and dependencies by po ...
. It was a member of the order of
Multituberculata
Multituberculata (commonly known as multituberculates, named for the multiple tubercles of their teeth) is an extinct Order (biology), order of rodent-like mammals with a fossil record spanning over 130 million years. They first appeared in the M ...
and is within 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 ...
. The genus ''Chulsanbaatar'' was named by
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 ...
in 1974 , after the locality of Khulsan near the dig sites where these organisms were found, and
Ulan Bator, the capital of Mongolia.
Fossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...
remains of the species ''Chulsanbaatar vulgaris'' have been found in multiple localities in the Gobi Desert, including the Red Beds of Hermiin Tsav (also known as Khermeen Tsav, part of the
Barun Goyot Formation
The Baruungoyot Formation (also known as Barun Goyot) is a geological formation dating to the Late Cretaceous Period. It is located within and is widely represented in the Gobi Desert Basin, in the Ömnögovi Province of Mongolia.
Descriptio ...
) in
Mongolia
Mongolia is a landlocked country in East Asia, bordered by Russia to the north and China to the south and southeast. It covers an area of , with a population of 3.5 million, making it the world's List of countries and dependencies by po ...
. They range in the fossil record from 84 to 71 million years ago, from the late
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 ...
, through the
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 early
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.
This small multituberculate had a long skull. Remarkably, it has been possible to study the ear bones, which shows how well some of the fossils are preserved. With several intact skulls having been found, it can be determined that ''C.vulgaris'' has a
dental formula
Dentition pertains to the development of teeth and their arrangement in the mouth. In particular, it is the characteristic arrangement, kind, and number of teeth in a given species at a given age. That is, the number, type, and morpho-physiology ...
of . The adult body mass has been estimated at , which is similar to a small modern mouse.
According to detailed reconstructions by Kielan-Jaworowska and Gambaryan, ''Chulsanbaatar'' was likely nocturnal due its large eyes, and had live births but relatively undeveloped young due to its pelvic structure. It likely was behaviorially similar to that of the modern
gerbil
The Mongolian gerbil or Mongolian jird (''Meriones unguiculatus'') is a rodent belonging to the subfamily Gerbillinae. Their body size is typically , with a tail, and body weight , with adult males larger than females. The animal is used in s ...
.
The type specimen of ''Chulsanbaatar'' is now a resident of the Polish Academy of Science in
Warsaw
Warsaw, officially the Capital City of Warsaw, is the capital and List of cities and towns in Poland, largest city of Poland. The metropolis stands on the Vistula, River Vistula in east-central Poland. Its population is officially estimated at ...
,
Poland
Poland, officially the Republic of Poland, is a country in Central Europe. It extends from the Baltic Sea in the north to the Sudetes and Carpathian Mountains in the south, bordered by Lithuania and Russia to the northeast, Belarus and Ukrai ...
. (ZPAL MgM-I/189). Kielan-Jaworowska noted ''C.vulgaris'' to be the most commonly found mammal in
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 ...
aged Gobi Desert dig sites and was precisely why she gave the species that name (common = ).
[Kielan-Jaworowaska, 1974, p 39]
Notes
References
*
*
*
*
{{Taxonbar, from=Q3676071
Cimolodonta
Santonian life
Campanian life
Late Cretaceous mammals of Asia
Fossils of Mongolia
Fossil taxa described in 1974
Prehistoric mammal genera