Lami-Comb rat

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Lami-Comb rat
Systematics
Subordination : Porcupine relatives (Hystricomorpha)
Partial order : Hystricognathi
without rank: Guinea Pig Relatives (Caviomorpha)
Family : Comb rats (Ctenomyidae)
Genre : Comb rats ( Ctenomys )
Type : Lami-Comb rat
Scientific name
Ctenomys lami
Freitas , 2001

The lami-comb rat ( Ctenomys lami ) is a type of comb- rat . The species is endemic to the east of the state of Rio Grande do Sul in Brazil .

features

The lami-comb rat reaches an average total length of 23.1 to 31.0 centimeters with a tail length of 6.7 to 9.2 centimeters and a weight of about 370 grams. The rear foot length is 31 to 42 millimeters, the ear length about 8 millimeters. It is a medium to large species of the genus. The back color is evenly dark brown, with the individual hairs being dark gray at the base and brown in the upper third. The ventral side is lighter brown.

The skull is comparatively broad; the brain skull is clearly oval in shape, and its length corresponds to about a third of the total length of the skull. The upper incisors are large and not protruding ( orthodontic ); they have orange-colored enamel . The nasal bones are wide in the front area and narrow towards the back. The zygomatic arches are strongly developed. The lower jaw has a distinct coronoid process.

The karyotype consists of a double set of chromosomes of 2n = 54 to 58 (FN = 76 to 82) chromosomes, whereby the haplotypes can vary widely within the species and the species thus has the highest variability of the karyotypes within the comb rats. The sperm are symmetrical.

distribution

The distribution area of ​​the lami crested rat is limited to the south of Brazil , where the species occurs endemically and is only proven in the east of the state of Rio Grande do Sul in a region called "Coxilha da Lombas". The holotype comes from Guaíba beach near Porto Alegre

Way of life

There is hardly any information about the way of life of the species. Like all comb rats, it lives largely underground in duct systems and feeds on the available vegetation, especially grass and leaves, as a vegetarian diet. As a habitat, it uses open, sandy areas of the lowlands in the area of ​​the dunes on the Guaiba and Barros lakes as well as anthropogenically influenced grass areas. The animals are loners (solitary). Between June and December the females give birth to litters of one to three pups each.

Systematics

The lami-comb rat is classified as an independent species within the genus of comb rats ( Ctenomys ), which consists of around 70 species. The first scientific description of the species comes from the Brazilian zoologist Thales Renato O. de Freitas from 2001, who described it using individuals from the Guaíba near Porto Alegre and differentiated it from the pygmy crested rat ( Ctenomys minutus ). Based on molecular biological data, it is assigned to the torquatus group around the collar-comb rat ( Ctenomys torquatus ).

Apart from the nominate form, no subspecies are distinguished within the species .

Status, threat and protection

The lami-comb rat is classified by the International Union for Conservation of Nature and Natural Resources (IUCN) as endangered ("vulnerable"). The classification is justified by the comparatively small distribution area of ​​about 14,700 km², whereby the species is only known from 10 sites and the availability of habitat is decreasing. The population has decreased dramatically in recent years due to the progressive urbanization of the habitats of this species.

A hybrid zone was identified between the populations of the lami-comb rat and the closely related dwarf -comb rat ( Ctenomys minutus ) . Originally both species were separated by a wide wetland zone; however, rice cultivation reduced the swamp to an arid region and the two species were merged. Urbanization and the expansion of agriculture, especially the cultivation of rice and soybeans , are seen as the main sources of threat to the species.

supporting documents

  1. ↑ a b c d e f g h i j k Lami Tuco-tuco. In: TRO Freitas: Family Ctenomyidae In: Don E. Wilson, TE Lacher, Jr., Russell A. Mittermeier (editor): Handbook of the Mammals of the World: Lagomorphs and Rodents 1. (HMW, Volume 6) Lynx Edicions, Barcelona 2016, p. 521. ISBN 978-84-941892-3-4 .
  2. ↑ Thales Renato O. de Freitas: Ctenomys lami: The highest chromosome variability in Ctenomys (Rodentia, Ctenomyidae) due to a centric fusion / fission and pericentric inversion system. Acta Theriologica 52, 2007; Pp. 171-180. doi : 10.1007 / BF03194212
  3. ↑ Ctenomys lami . In: Don E. Wilson , DeeAnn M. Reeder (Eds.): Mammal Species of the World. A taxonomic and geographic Reference. 2 volumes. 3. Edition. Johns Hopkins University Press, Baltimore MD 2005, ISBN 0-8018-8221-4 .
  4. ↑ Thales Renato O. de Freitas: Tuco-tucos (Rodentia, Octodontidae) in Southern Brazil: Ctenomys lami spec. nov. Separated from C. minutus Nehring 1887. Studies on Neotropical Fauna and Environment 36 (1), 2001; Pp. 1-8.
  5. ↑ a b c d Ctenomys lami in the endangered Red List species the IUCN 2019. Posted by: CJ Bidau, 2016. Accessed April 24, 2020th

literature

  • Lami Tuco-tuco. In: TRO Freitas: Family Ctenomyidae In: Don E. Wilson, TE Lacher, Jr., Russell A. Mittermeier (editor): Handbook of the Mammals of the World: Lagomorphs and Rodents 1. (HMW, Volume 6) Lynx Edicions, Barcelona 2016, p. 521. ISBN 978-84-941892-3-4 .

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