Small bare-tailed armadillo
| Small bare-tailed armadillo | ||||||||||||
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Small bare- tailed armadillo ( Cabassous chacoensis ) |
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| Cabassous chacoensis | ||||||||||||
| Wetzel , 1980 |
The small bare - tailed armadillo or Chaco bare-tailed armadillo ( Cabassous chacoensis ) is the smallest representative of the bare-tailed armadillos and lives mainly in the arid landscapes of the Gran Chaco in South America . Very little is known about his way of life. According to the IUCN, the species is only slightly endangered.
features
Habitus
The small bare - tailed armadillo reaches a head-torso length of 31 cm, plus a long and narrow tail with an average length of 9.3 cm. The weight is 1.5 to 1.6 kg. The head is short and broad, the eyes are characteristically small. The small and widely spaced ears are only 1.4 cm long and are therefore significantly smaller than those of the other bare-tailed armadillos . The head shield, which consists of 25 to 29 bone platelets and is triangular in shape, is striking. The back armor covers both the shoulder and pelvic regions and extends down to the limbs. It is dark brown in color, a little lighter on the sides. It is made up of individual bands of bone platelets, with 16 to 27 platelets forming a row in the shoulder area and 25 to 5 in the pelvic area (counting from front to back). Between the more solid shoulder and pelvic armor there are twelve movable ligaments with an average of 28 to 29 platelets each. The tail has no bone platelets and is bare. Hair, which is sometimes quite long, is only found on the sides of the body below the back armor, but the belly is largely hairless. The very short limbs end in five claws each at the front and back. Those of the forefoot are long, especially on the middle (third) ray. When running, the animal uses the entire sole of the hind feet, while the claws put on the front feet. The rear foot becomes 6.1 cm long.
Skeletal features
The skull is 6.8 cm long and at the cheekbones up to 4 cm wide, the height is 3 cm. The rostrum is comparatively shorter and wider than that of other bare-tailed armadillos. The lower jaw has a narrow shape. The teeth do not correspond to those commonly formed in mammals . They resemble a little the molars , are wider than long on average 2.5 mm in size. In the upper jaw there are eight to nine of these teeth, and in the lower jaw eight of these teeth are formed per jaw arch, so a total of 32 to 34 teeth are in the set. The length of the row of teeth in the upper jaw is 2.6 cm, in the lower jaw 2.4 cm. The ulna on the forelegs is remarkable. It becomes 4.8 cm long, the upper joint end ( olecranon ) of which alone takes 2.2 cm. Such a large joint is typical for mammals with a burrowing way of life.
Sensory performances and vocalizations
Only a squeak reminiscent of pigs is known from male animals. Females hardly seem to make any sounds.
distribution and habitat
The distribution area includes the western part of Paraguay and northern Argentina . Information from Bolivia and southern Brazil has not yet been confirmed. The settlement area is given as 438,000 km², but the population density is unknown. The small bare-tailed armadillo mainly lives in dry areas of the Gran Chaco , which consists of open landscapes and dry forests with thorny bushes. Here it often occurs in areas with dense growth from Prosopis and Quebracho trees . In addition, the soils consist of loose, non-clayey sediments. The small bare-tailed armadillo avoids cultivated areas.
Way of life
The small bare-tailed armadillo is very rarely observed, in the period since the late 1980s only very few sightings documented by scientists have become known, so almost nothing is known about their way of life. The armadillo is believed to be nocturnal, but some sightings have also occurred during the day. She continues to live underground in caves that she probably dug herself. According to reports, she leaves these when thunderstorms are approaching . The main food consists of ants and termites , the burrows of which the small bare-tailed armadillo break open with its claws. In addition, the animal seems to be able to track down water very well. Females usually give birth to a young during reproduction.
Systematics
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Internal systematics of the armadillos according to Gibb et al. 2015
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The small bare-tailed armadillo belongs to the genus of bare- tailed armadillos ( Cabassous ), to which three other species can be assigned. These in turn are all referred to the group of armadillos (Dasypoda) and to the family of Chlamyphoridae . Within the family, the genus Cabassous is a member of the subfamily of the Tolypeutinae , the closest related forms are the giant armadillos ( Priodontes ) and the spherical armadillos ( Tolypeutes ). The Tolypeutinae are the sister taxons of the Chlamyphorinae , which include the two belt mole species . The subfamily of Euphractinae with the bristle armadillos ( Chaetophractus ) and the six-banded armadillo ( Euphractus ) are related in some distance. According to molecular genetic studies, the Chlamyphorinae and the Tolypeutinae separated already in the Oligocene 33 million years ago, after which the Tolypeutinae were subject to a stronger division since the early Miocene . Fossil evidence of the small bare-tailed armadillo is not known.
There are no known subspecies of the lesser bare-tailed armadillo, so the species is monotypical. It was described in 1980 by Ralph Martin Wetzel in the course of a revision of the Cabassous genus , as a type region he gave the area 5 to 7 km west of Estancia Juan de Zalazar in the Paraguayan Department Presidente Hayes . The species name chacoensis refers to the Gran Chaco region as a habitat.
Threat and protection
The small bare-tailed armadillo occurs in regions with an average of very thin human colonization; the greatest threat is the loss of habitat through agriculture , especially through the increased cultivation of peanuts , sorghum and sesame , for which the soft soils are predestined. In addition, it is often tracked down by domestic dogs roaming free in its living caves. Sometimes it also serves as food for humans. The IUCN currently classifies the animal species as " near threatened "; some researchers assume a decline of up to 25% of the total population due to the increasing agriculture in the Gran Chaco region and plead for a higher endangerment classification. In Argentina it is native to some national parks, such as the Talampaya National Park .
literature
- Virginia Hayssen: Cabassous chacoensis (Cingulata: Dasypodidae). Mammalian Species 46 (908), 2014, pp. 24-27
- Mariella Superina and Agustín Manuel Abba: Chlamyphoridae (Chlamyphorid armadillos). In: Don E. Wilson and Russell A. Mittermeier (eds.): Handbook of the Mammals of the World. Volume 8: Insectivores, Sloths and Colugos. Lynx Edicions, Barcelona 2018, pp. 48-71 (pp. 70-71) ISBN 978-84-16728-08-4
Individual evidence
- ^ A b S. F. Vizcaíno and N. Milne: Structure and function in armadillo limbs (Mammalia: Xenarthra: Dasypodidae). Journal of Zoology 257, 2002, pp. 257, 117-127
- ↑ a b c d e f g Paul Smith: Chaco naked-tailed armadillo Cabasssous chacoensis Wetzel, 1980. Mammals of Paraguay 25, 2008, pp. 1-7
- ↑ a b c d e Virginia Hayssen: Cabassous chacoensis (Cingulata: Dasypodidae). Mammalian Species 46 (908), 2014, pp. 24-27
- ↑ a b c Mariella Superina and Agustín Manuel Abba: Chlamyphoridae (Chlamyphorid armadillos). In: Don E. Wilson and Russell A. Mittermeier (eds.): Handbook of the Mammals of the World. Volume 8: Insectivores, Sloths and Colugos. Lynx Edicions, Barcelona 2018, pp. 48-71 (pp. 70-71) ISBN 978-84-16728-08-4
- ^ Anteater, Sloth and Armadillo Specialist Group: Cabassous chacoensis. Edentata 11 (2), 2010, pp. 140-141
- ↑ Dennis A. Meritt Jr .: Xenarthrans of the Paraguayan Chaco. In: Sergio F. VizcaínoW. J. Laughry (Ed.): The Biology of the Xenarthrans. University Press of Florida, Gainesville, 2008, pp. 294-299
- ↑ a b Julio C. Monguillot and Rodolfo Miatello: Presencia de Cabassous chacoensis en el Parque Nacional Talampaya, La Rioja, Argentina. Edentata 8-10, 2009, pp. 56-57
- ^ Daniela María Tamburini and Cecilia Verónica Briguera: Nuevo registro del cabasú chaqueño, Cabassous chacoensis Wetzel, 1980 para la Provincia de Córdoba, Argentina. Edentata 13, 2012, pp. 69-71
- ^ A b Paul Smith: Assessing the assessment, the relevance of the 2006 Paraguayan mammal Red List to the reality of Xenarthra conservation in 2012. Edentata 13, 2012, pp. 18-28
- ↑ a b Gillian C. Gibb, Fabien L. Condamine, Melanie Kuch, Jacob Enk, Nadia Moraes-Barros, Mariella Superina, Hendrik N. Poinar and Frédéric Delsuc: Shotgun Mitogenomics Provides a Reference Phylogenetic Framework and Timescale for Living Xenarthrans. Molecular Biology and Evolution 33 (3), 2015, pp. 621-642
- ↑ Maren Möller-Krull, Frédéric Delsuc, Gennady Churakov, Claudia Marker, Mariella Superina, Jürgen Brosius, Emmanuel JP Douzery and Jürgen Schmitz: Retroposed Elements and Their Flanking Regions Resolve the Evolutionary History of Xenarthran Mammals (Armadillos, Anteaters and Sloths). Molecular Biology and Evolution 24, 2007, pp. 2573-2582
- ↑ Frederic Delsuc, Mariella Superina, Marie-Ka Tilak, Emmanuel JP Douzery and Alexandre Hassanin: Molecular phylogenetics unveils the ancient evolutionary origins of the enigmatic fairy armadillos. Molecular Phylogenetics and Evolution 62, 2012, 673-680
- ↑ Frédéric Delsuc, Sergio F Vizcaíno and Emmanuel JP Douzery: Influence of Tertiary paleoenvironmental changes on the diversification of South American mammals: a relaxed molecular clock study within xenarthrans. BMC Evolutionary Biology 4 (11), 2004, pp. 1-13
- ↑ Mariella Superina and Augusín M. Abba: Cabassous chacoensis. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. ( [1] ) last accessed on January 2, 2013
Web links
- Cabassous chacoensis in the endangered Red List species the IUCN 2006. Posted by: Abba & Superina, 2006. Retrieved on January 2, 2013.