Striped crested rat
|Striped crested rat|
|Thomas , 1900|
The striped crested rat or Chaco crested rat ( Ctenomys dorsalis ) is a barely researched rodent from the family of crested rats (Ctenomyidae). It occurs in Paraguay .
The average total length of 17 measured specimens is 230 mm. The average tail length of this is 64 mm. The average skull length is 39.77 mm. The head-trunk length of the type specimen is 156 mm, the tail length 46 mm and the hind foot length 30 mm. No specific data are available on weight. The fur is soft and thin. The back is light yellow-brown. A black mottled back line runs from the nose to the rump and a clearly defined line 10 mm wide on the head, which is visible as a fuzzy band on the back. There are no dark markings around the eyes and ears as in similar species of comb rats, but there is a clearly outlined light collar pattern that extends from behind the cheeks and chin to behind the ears. The throat, chest, outer sides of the abdomen and a narrow central stripe are light yellow-brown with gray basic hair. The rest of the belly hair is white. The tail hairs are black and white. The front teeth are orange.
distribution and habitat
The striped rat is only known from the two localities Colonia Fernheim and Orloff, which are in the Paraguayan Gran Chaco in the Boquerón department and 30 km apart on both sides of the city of Filadelfia . The entire area was converted into agricultural land no later than the 1920s, when the first Mennonite colonies were founded in western Paraguay. The original vegetation corresponds to that of the Chaco árido ecoregion , a landscape characterized by a mosaic of thorn forest, shrubbery, tree cacti and grass savannahs. The location and date of collection of the holotype of Ctenomys dorsalis has not yet been adequately clarified. At the time of the collection, the "Paraguayan Chaco" was a much smaller area than it is today. After the war between Bolivia and Paraguay ( Chaco War 1932–1935) it was expanded. Based on the routes described by John Graham Kerr , Julio Rafael Contreras and Virgilio Germán Roig suggested that the holotype was collected in the Department of Presidente Hayes . Should your doubts be proven that Oldfield Thomas incorrectly gave the collection date May 7, 1900, there are at least two locations in the Chaco that Kerr visited on May 7, one in 1890 and another in 1897 In 1890 Kerr traveled between Las Juntas and Fortín Page, near today's border with Argentina. In 1897, Kerr worked at the Misión Inglesa in Waikhtlatingmalyalwa. These two locations are 325 km southeast and 200 km southeast of the areas described. In this second location, Kerr collected the holotype of Akodon lenguarum (now Necromys lenguarum ) on May 10, 1897 , whose terra typica is given by Thomas as "Waikthlatingmayalwa, North Chaco of Paraguay". Another plausible assumption comes from Contreras and Roig, based on the local common name Sumkum , which the indigenous groups used to refer to the animal that Kerr had collected. These authors found that a careful study of the vocabulary of the different tribes that make up the Chaco is helpful in determining the origin of the type specimen. Coincidentally, the word Soomcon was added to the vocabulary of the Enlhet , an indigenous group from the central Chaco who were native to the Misión Inglesa. Contreras and Roig believe there are several lines of evidence to suggest that it is entirely possible that Kerr collected the C. dorsalis holotype at or near Waikhtlatingmalyalwa, where that researcher spent most of May 1897.
Way of life
The way of life of this species is not documented. The striped crested rat, however, plays a major role in maintaining the ecological processes in the arid Chaco. Digging underground passages buries foliage, bringing in enough moisture to break down the leaf litter.
Hazard and protection
For a long time the species was only known from the holotype, a female that is in the Natural History Museum in London . In 2018, 17 more specimens were examined, which were collected in July 1945 by Pedro Willim in the Department of Boquerón and are kept in the Field Museum of Natural History in Chicago . The characteristics correspond to those that Oldfield Thomas had made in his first description . The IUCN classifies the species in the category "insufficient data" ( data deficient ). However, given the various regional changes caused by human activities such as agriculture and livestock farming, as well as the limited range of the striped crested rat, it is possible that this rodent could be classified as an endangered species. Field work in the Paraguayan Chaco is urgently needed to assess the conservation status of the striped crested rat.
- Claudio Juan Bidau: Ctenomys dorsalis Thomas, 1900 In: James L. Patton, Ulyses FJ Pardinas, Guillermo D'Elía (Eds.): Mammals of South America, Volume 2 - Rodents. The University of Chicago Press, Chicago 2015; P. 832, ISBN 978-0-226-16957-6 .
- Thales Freitas: Family Ctenomyidae (Tuco-tucos). In: Don Ellis Wilson and Russell Mittermeier (Eds.): Handbook of the Mammals of the World. Volume 6: Lagomorphs and Rodents 1 Lynx Edicions, Barcelona 2016, ISBN 978-84-941892-3-4 , p. 529
- Manuela Londoño-Gaviria, Pablo Teta, Sergio D. Ríos and Bruce D. Patterson: Redescription and phylogenetic position of Ctenomys dorsalis Thomas 1900, an enigmatic tuco tuco (Rodentia, Ctenomyidae) from the Paraguayan Chaco Mammalia, September 2018.
- Ctenomys dorsalis inthe IUCN 2018.1 Red List of Threatened Species . Posted by: C. Bidau, E. Lessa, R. Ojeda, 2008. Retrieved October 3, 2018.
- ^ John G. Kerr: A naturalist in the Gran Chaco. Cambridge University Press, Cambridge. P. i – xv + 1–235 + 1 map + plates I – XXIV, 1950
- ↑ a b c d J. R. Contreras and VG Roig: Las especies del género Ctenomys (Rodentia: Octodontidae). I. Ctenomys dorsalis Thomas, 1900. Nótulas Faunísticas 34, 1992, pp. 1-4.
- ↑ Manuela Londoño-Gaviria, Pablo Teta, Sergio D. Ríos and Bruce D. Patterson: Redescription and phylogenetic position of Ctenomys dorsalis Thomas 1900, an enigmatic tuco tuco (Rodentia, Ctenomyidae) from the Paraguayan Chaco Mammalia, September 2018.