The Bristle-spined Porcupine, Chaetomys subspinosus, is an arboreal rodent from Brazil. Also known as the Thin-spined Porcupine, it is the only member of the genus Chaetomys and the subfamily Chaetomyinae. Scientific classification or biological classification is how biologists group and categorize extinct and living species of organisms. ... Jump to: navigation, search Phyla Porifera (sponges) Ctenophora (comb jellies) Cnidaria Placozoa Subregnum Bilateria  Acoelomorpha  Orthonectida  Rhombozoa  Myxozoa  Superphylum Deuterostomia     Chordata (vertebrates, etc. ... Typical Classes Subphylum Urochordata - Tunicates Ascideiacea Thaliacea Larvacea Subphylum Cephalochordata - Lancelets Subphylum Myxini - Hagfishes Subphylum Vertebrata - Vertebrates Petromyzontida - Lampreys Placodermi (extinct) Chondrichthyes - Cartilaginous fishes Acanthodii (extinct) Actinopterygii - Ray-finned fishes Actinistia - Coelacanths Dipnoi - Lungfishes Amphibia - Amphibians Reptilia - Reptiles Aves - Birds Mammalia - Mammals Chordates (phylum Chordata) include the vertebrates, together with... Jump to: navigation, search Orders Subclass Multituberculata (extinct) Plagiaulacida Cimolodonta Subclass Palaeoryctoides (extinct) Subclass Triconodonta (extinct) Subclass Placentalia Afrosoricida Artiodactyla Carnivora Cetacea Chiroptera Creodonta (extinct) Dermoptera Desmostylia (extinct) Embrithopoda (extinct) Hyracoidea Insectivora Lagomorpha Litopterna (extinct) Macroscelidea Notoungulata (extinct) Perissodactyla Pholidota Primates Proboscidea Rodentia Scandentia Sirenia Tubulidentata Xenarthra Subclass Marsupialia Dasyuromorphia... Families Many, see text The order Rodentia is the most numerous of all the branches on the mammal family tree. ... Hystricognathi is a subordo of the Rodentia. ... Caviomorpha is an infraorder of hystricognath rodents. ... Genera  Coendou  Sphiggurus  Erethizon  Echinoprocta The New World porcupines are large terrestrial rodents, distinguished by their spiny covering from which they take their name. ... Jump to: navigation, search Genera †Cercomys †Maruchito †Paulacoutomys †Willidewu †Adelphomys †Deseadomys †Paradelphomys †Stichomys †Xylechimys Dactylomys Kannabateomys Olallamys †Boromys †Brotomys †Heteropsomys †Puertoricomys †Acarechimys †Chasichimys †Eumysops Lonchothrix Mesomys †Palaeoechimys †Pampamys †Pattersomys †Protacaremys †Protadelphomys †Sallamys Proechimys Thrichomys Trinomys Carterodon Clyomys Euryzygomatomys Callistomys Diplomys Echimys Isothrix Makalata Pattonomys Phyllomys Santamartamys The spiny rats are... Michael Rogers Oldfield Thomas (February 21, 1858 - June 16, 1929) was a British zoologist. ... Jump to: navigation, search 1897 was a common year starting on Friday (see link for calendar). ... 1843 was a common year starting on Sunday (see link for calendar). ... 1818 is a common year starting on Thursday. ... In biology, binomial nomenclature is a standard convention used for naming species. ... 1818 is a common year starting on Thursday. ... This article is about the biological organisms known as trees. ... Jump to: navigation, search Families See Classification Section The order Rodentia is the most numerous of all the branches on the mammal family tree. ...

Characteristics

Bristle-spined Porcupines are named because the spines on the back are more bristle-like in texture than the spines on the rest of the body. They have long naked tails which are not prehensile. Adult animals weigh around 1.3 kg. Prehensility is the quality of an organ that has adapted for grasping or holding. ...

Their skulls are unusual in several ways. The eye socket is almost completely surrounded by a ring of bone. Incisors are distinctly narrow. Overall, the animal displays a mix of New World porcupine cranial characters, spiny rat cranial characters, and characters that set it apart from all other rodents.

The Bristle-spined Porcupine is restricted to remnant forests and forest edges in the Atlantic coastal forests on the East Coast of Brazil. Its habitat is dwindling rapidly and the species may be vulnerable to extinction. It is classified as vulnerable by IUCN and endangered by USDI (Nowak, 1999). In biology and ecology, extinction is the ceasing of existence of a species or group of taxons. ... The World Conservation Union or International Union for Conservation of Nature and Natural Resources (IUCN) is an international organization dedicated to natural resource conservation. ... This is a list of all endangered species listed by the federal government. ...

Taxonomic controversy

Non consensus has been reached as to the taxonomic position of Chaetomys. It is commonly placed with the New World porcupines in the family Erethizontidae or with the spiny rats the family Echimyidae. Both are South American hystricognaths with hairs modified as spines or quills. Chaetomys has more highly developed spines than the spiny rats, but less developed than the porcupines. Characteristics of the premolar suggest that it belongs with the Echimyidae, but characteristics of the incisor enamel suggest that it belongs in the Erethizontidae. Genera  Coendou  Sphiggurus  Erethizon  Echinoprocta The New World porcupines are large terrestrial rodents, distinguished by their spiny covering from which they take their name. ... Jump to: navigation, search Genera †Cercomys †Maruchito †Paulacoutomys †Willidewu †Adelphomys †Deseadomys †Paradelphomys †Stichomys †Xylechimys Dactylomys Kannabateomys Olallamys †Boromys †Brotomys †Heteropsomys †Puertoricomys †Acarechimys †Chasichimys †Eumysops Lonchothrix Mesomys †Palaeoechimys †Pampamys †Pattersomys †Protacaremys †Protadelphomys †Sallamys Proechimys Thrichomys Trinomys Carterodon Clyomys Euryzygomatomys Callistomys Diplomys Echimys Isothrix Makalata Pattonomys Phyllomys Santamartamys The spiny rats are... South America South America is a continent crossed by the equator, with most of its area in the Southern Hemisphere. ... Jump to: navigation, search The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ... The premolar teeth or bicuspids are transitional teeth located between the canine and molar teeth. ... Incisors are the first kind of tooth in heterodont mammals. ... The word enamel can mean more than one thing: Tooth enamel Vitreous enamel Enamel (markup language) Enameled wire This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ...

Patterson and Pascual (1968), Patterson and Wood (1982), Woods (1982, 1984, 1993) Patton and Reig (1989), Nowak (1999), and Carvalho (2000) suppport the inclusion of this animal in the Echimyidae whereas Martin (1994), McKenna and Bell (1997), and Carvalho and Salles (2004) argue that it belongs in the Erethizontidae. Emmons (2005) mentions the family Chaetomyidae without much further comment except to exclude it from Echimyidae.

References

• Carvalho, 2000. Substitution of the deciduous premolar in Chaetomys subspinosus (Olfers, 1818) (Hystricognathi, Rodentia) and its taxonomic implications. Zeitschrift für Säugetierkunde, 65:187-190.
• Carvalho, G. A. S. and L. O. Salles. 2004. Relationships among extant and fossil echimyids. Zoological Journal of the Linnean Society, 142:445-477.
• Emmons, L.H. 2005. A Revision of the Genera of Arboreal Echimyidae (Rodentia: Echimyidae, Echimyinae), With Descriptions of Two New Genera. Pp. 247-310 in Lacey, E.A. & Myers, P. 2005. Mammalian Diversification: From Chromosomes to Phylogeography (A Celebration of the Career of James L. Patton). University of California Publications in Zoology.
• Martin, T. 1994. On the systematic position of Chaetomys subspinosus (Rodentia: Caviomorpha) based on evidence from the incisor enamel microstructure. Journal of Mammalian Evolution, 2:117-131.
• McKenna, Malcolm C., and Bell, Susan K. 1997. Classification of Mammals Above the Species Level. Columbia University Press, New York, 631 pp. ISBN 0-231-11013-8
• Nowak, R. M. 1999. Walker's Mammals of the World, Vol. 2. Johns Hopkins University Press, London.
• Patton, J. L. and O. A. Reig. 1989. Genetic differentiation among echimyid rodents, with emphasis on spiny rats, genus Proechimys. Pp. 75-96 in Neotropical Mammalogy (K. H. Redford and J. F. Eisenberg, eds.). Sandhill Crane Press, Gainesville.
• Patterson, B. and R. Pascual. 1968. New echimyid rodents from the Oligoceneof Patagonia, and a synopsis of the family. Brevioria, 301:1-14.
• Patterson, B. and A. E. Wood. 1982. Rodents from the Deseadan Oligocene of Bolivia and the relationships of the Caviomorpha. Bulletin of the Museum of Comparative Zoology, 149:371-543.
• Woods, C. A. 1982. The history and classification of the South American hystricognath rodents: Reflections on the far away and long ago. Pymatuning Laboratory of Ecology Special Publication, 6:377-392.
• Woods, C. A. 1984. Hystricognath rodents. Pp. 389-446 in Anderson and Jones eds. Orders and families of Recent mammals of the world. John Wiley and Sons, New York.
• Woods, C. A. 1993. Hystricognathi. In Mammal Species of the World a Taxonomic and Geographic Reference. D. E. Wilson and D. M. Reeder eds. Smithsonian Institution Press, Washington D.C.

External links

• Animal Diversity Web page on Chaetomys