Laotian Rock Rat
From Wikipedia
| Laotian Rock Rat | ||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Scientific classification | ||||||||||||||||
| ||||||||||||||||
| Binomial name | ||||||||||||||||
| Laonastes aenigmamus (Jenkins, Kilpatrick, Robinson, Timmins, 2005) |
The Kha-nyou or Laotian Rock Rat (Laonastes aenigmamus) is a rodent from the Khammouan region of Laos. The species was first described in an article issued 18 April 2005 by Jenkins and colleagues who considered it to be so distinct from all living rodents that they placed it in a new family, Laonastidae. The animals resemble large dark rats with a haired thick tail. Their skulls are very distinct and have features that separate them from all other mammals. In biology, binomial nomenclature is a standard convention used for naming species. ... 2005 is a common year starting on Saturday of the Gregorian calendar. ... Families Many, see text The order Rodentia is the most numerous of all the branches on the mammal family tree. ... Khammouan (Lao ຄໍາມ່ວນ) is a province of Laos, located in the south of the country. ... The Lao Peoples Democratic Republic is a landlocked country in southeast Asia, bordered by Myanmar (commonly known in the west as Burma) and the Peoples Republic of China to the northwest, Vietnam to the east, Cambodia to the south, and Thailand to the west. ... April 18 is the 108th day of the year in the Gregorian calendar (109th in leap years). ... 2005 is a common year starting on Saturday of the Gregorian calendar. ... This is an article about wild rats; for pet rats, see Fancy rat Species 50 species; see text *Several subfamilies of Muroids include animals called rats. ... This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... For symbolic or mythic uses of the human skull, see Skull (symbolism). ...
| Table of contents |
A new family
The discovery of a new species of extant mammal that represents a completely new family is a rare occurrence. The most recent incident prior to the discovery of the Laotian rock rat by western science was the discovery of the bumblebee bat (Craseonycteris thonglongyai; family Craseonycteridae) in 1974. The only other examples from the 1900s are represented by species that are only considered distinct families by a few authorities. These discoveries are: Chinese river dolphin (Lipotes vexillifer; family Lipotidae) in 1918, Zagros mouse-like hamster (Calomyscus bailwardi; family Calomyscidae) in 1905, and Goeldi's marmoset (Callimico goeldii; family Callimiconidae) in 1904. The Kalinowski's Opossum (Hyladelphys kalinowskii), described only in 1992, is currently assigned to the family Didelphidae, but it may represent its own family. Representatives from all the remaining mammal families with living representatives (~30) were discovered prior to 1900. The Bumblebee Bat or perhaps more correctly Kittis Hog-nosed Bat, (Craseonycteris thonglongyai) is the worlds smallest species of bat at 29-33 mm in length and a weight of 2 grams (about as much as a dime). ... The Bumblebee Bat or perhaps more correctly Kittis Hog-nosed Bat, (Craseonycteris thonglongyai) is the worlds smallest species of bat at 29-33 mm in length and a weight of 2 grams (about as much as a dime). ... 1974 is a common year starting on Tuesday (click on link for calendar). ... Binomial name Lipotes vexillifer Miller, 1918 The Chinese River Dolphin (Lipotes vexillifer) is a freshwater dolphin found only in the Yangtze River in China. ... Binomial name Lipotes vexillifer Miller, 1918 The Chinese River Dolphin (Lipotes vexillifer) is a freshwater dolphin found only in the Yangtze River in China. ... 1918 was a common year starting on Tuesday (see link for calendar). ... Species see text Mouse-like hamsters are a group of small rodents found in Syria, Azerbaijan, Turkmenistan, Pakistan. ... 1905 was a common year starting on Sunday (see link for calendar). ... Binomial name Callimico goeldii Thomas, 1904 Goeldis Marmoset or Goeldis Monkey (Callimico goeldii) is a small, South American New World monkey that lives in the upper Amazon Basin region of Brazil, Colombia, Ecuador, and Peru. ... 1904 is a leap year starting on a Friday (link will take you to calendar). ... 1992 is a leap year starting on Wednesday of the Gregorian calendar. ... Genera Several; see text The order Didelphimorphia contains the common opossums of the western hemisphere. ... 1900 is a common year starting on Monday. ...
Etymology
The genus name for this animal, Laonastes, means "inhabitant of stone". This is in reference to its presence around limestone rocks. The specific epithet aenigmamus means "enigmatic mouse" referring to its unknown position among the rodents.
Discovery
The first specimens were found for sale as meat at a market in Thakhek, Khammouan in 1996. Remains of three additional animals were obtained in 1998 from villagers and in an owl pellet. Several more animals were trapped in the region. Interestingly, the researchers also obtained two additional rodent species on that expedition that were unknown to science. These animals, however, could be assigned to known genera (Niviventer, and Hylomys) 1996 is a leap year starting on Monday of the Gregorian calendar, and was designated the International Year for the Eradication of Poverty. ... 1998 is a common year starting on Thursday of the Gregorian calendar, and was designated the International Year of the Ocean. ...
Description
The animals look like rats with furred thick tails. They are about 26 cm long with a 14 cm tail and weigh about 400 g. They have a hystricognathous jaw and an enlarged infraorbital foramen consistent with a hystricomorphous zygomasseteric system. The pterygoid fossa do not connect to the orbit making them unique among the hystricognathous rodents. In anatomy the orbit is the cavity or socket of the skull in which the eye and its appendages are situated. ...
Natural history
The Laotian Rock Rats are found in regions of karst limestone. They appear to be found only among limestone boulders on hillsides. Villagers know the animal, calling it kha-nyou, and trap the rodents for food. The animals are presumed to be nocturnal. Karst topography occurs when a landscape is marked by underground drainage patterns. ... Limey shale overlaid by limestone. ... A nocturnal animal is one that sleeps during the day and is active at night - the opposite of the human (diurnal) schedule. ...
These rock rats appear to be predominantly herbivores, eating leaves, grass and seeds. Insects may be eaten as well, but probably not in high abundance. Females may give birth to a single young. In zoology, an herbivore is an animal that is adapted to eat primarily plants (rather than meat). ...
This article is about the leaf, a plant organ. ...
In popular language grass means a short, green, ground covering or lawn, usually, but not necessarily comprised of a true grass or grasses, called turf. ...
This writeup is about biological seeds; for other meanings see Seed (disambiguation). ...
Orders Subclass Apterygota Symphypleona - globular springtails Subclass Archaeognatha (jumping bristletails) Subclass Dicondylia Monura - extinct Thysanura (common bristletails) Subclass Pterygota Diaphanopteroidea - extinct Palaeodictyoptera - extinct Megasecoptera - extinct Archodonata - extinct Ephemeroptera (mayflies) Odonata (dragonflies and damselflies) Infraclass Neoptera Blattodea (cockroaches) Mantodea (mantids) Isoptera (termites) Zoraptera Grylloblattodea Dermaptera (earwigs) Plecoptera (stoneflies) Orthoptera (grasshoppers, crickets...
To what are they related?
The results of the phylogenetic analyses performed by Jenkins et al. (2005) are somewhat inconclusive and contradictory. Both morphology and molecules show Laonastes as a member of the rodent suborder Hystricognathi. The morphological analysis suggests that it is the most basal member of the suborder. This would suggest that this living fossil represents the first living evolutionary split among the hystricognaths. In other words, all living members of the suborder Hystricognathi are more closely related to one another than to the Laotian rock rat. A phylogeny (or phylogenesis) is the origin and evolution of a set of organisms, usually of a species. ... Morphology is the following: In linguistics, morphology is the study of the structure of word forms. ... Molecular systematics is a product of the traditional field of systematics and the growing field of bioinformatics. ... Greek clados = branch) or phylogenetic systematics is a branch of biology that determines the evolutionary relationships of living things based on derived similarities. ... Living fossil is a term for any living species which closely resembles a species otherwise only known from fossils, i. ...
The molecular analyses suggest that Laonastes is related to the living African hystricognaths such as the dassie rats and the naked mole rat. Another type of analysis on the same data produces the same result as morphology; Laonestes represents the earliest split among hystricognaths. Neither analysis, however, shows more than moderate statistical support for the relationship of Laonastes within the hystricognaths. Binomial name Heterocephalus glaber Rüppell, 1842 The Naked Mole Rat (Heterocephalus glaber), or Sand Puppy, is a very unusual burrowing rodent native to arid parts of East Africa. ...
References
- Jenkins, P. D., C. W. Kilpatrick, M. F. Robinson, and R. J. Timmins. 2005. Morphological and molecular investigations of a new family, genus and species of rodent (Mammalia: Rodentia: Hystricognatha) from Lao PDR. Systematics and Biodiversity, 2:419-454.
- Wilson, D. E. and D. M. Reeder. 1993. Mammal Species of the World: A Taxonomic and Geographic Reference. Washington D.C., Smithsonian Institution Press.
