Bristle armadillos
| Bristle armadillos | ||||||||||||
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Small bristle armadillo ( C. vellerosus ) |
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| Scientific name | ||||||||||||
| Chaetophractus | ||||||||||||
| Fitzinger , 1871 |
The chaetophractus ( Chaetophractus ) are a mammalian species selected from the group of the armadillo (Dasypoda). They get their name from the bristle-like hair on the shell. The genus is now divided into two types: the brown-bristle armadillo ( C. villosus ) and the small bristle armadillo ( C. vellerosus ). The " Andean bristle armadillo " ( C. nationi ) was considered a separate species until 2016, but was then combined with the small bristle armadillo due to the lack of characteristic differences. In addition, the dwarf armadillo ( Zaedyus pichyi ), which is to be regarded as an independent genus, according to genetic studies, is within the bristle armadillos, which means that the latter are not a closed unit. The bristle armadillos live in arid and open landscapes in South America and feed as omnivores .
description
Bristle armadillos are largely small to medium-sized armadillos with a head-trunk length of about 20 to 36 cm and a tail length of 9 to 18 cm. The weight varies between 0.5 and 3.5 kg. The head is armored with a shield made of small, bony plates and extends almost to the tip of the nose. The ears are rather short, set wide apart and have rounded ends. The dentition differs from that of the other mammals and consists of characteristic tooth formations that have no enamel and only one root. In the upper jaw there are 9, in the lower jaw 9 or 10 such teeth per half of the jaw, a total of 36 to 38. The bristle armadillos differ from most other armadillo species in their strong body hair, which also includes the back armor. The hair on the back is light to dark brown, on the underside as well as on the limbs, which are more often equipped with a thicker coat, light brown to white. The back armor has a strikingly wide and flat shape and is divided into ribbon-like segments, which, like the head shield, consist of individual, small bone plates. Between the two fixed shoulder and pelvic parts of the tank there are seven to nine movable straps. At the rear end of the armor there are individual holes in the platelets in which glands are formed. These produce a secretion which gives the bristle armadillos a characteristic scent. The short legs end in front and back in five clawed toes.
distribution
Bristle armadillos mainly inhabit the central and southern part of South America . The distribution area includes southern Bolivia , Paraguay , Argentina , northern Chile and southern Peru . Individual groups were also settled on Tierra del Fuego . Open and rather dry habitats such as grasslands or semi-deserts, especially the pampas region and Patagonia , are preferred . A population of the lesser bristle armadillo is relatively isolated in the high altitudes of the Andes at an altitude of up to 4000 m.
Way of life
Territorial behavior
-1.JPG)
Bristle armadillos are solitary animals that maintain activity spaces that cover up to 3.5 hectares. They dig burrows several meters long with their claws, which they use as resting places. They also try to escape predators, including big cats and birds of prey , by burying themselves. If this does not succeed, they press themselves firmly to the ground to protect the unarmored belly and ram their claws into the ground. Furthermore, bristle armadillos do not have a fixed period of activity, this depends on the climate and season. In summer in hot areas they are quite nocturnal, in winter in cool areas they are diurnal.
food
Bristle armadillos are omnivores that consume both vegetable materials, which mainly include fruits , roots and tubers , and animal remains such as insects , maggots , small vertebrates and carrion . According to reports, individual members of the bristle armadillos burrow into the carcasses of larger animals to consume carcasses and insects. There are indications that the food spectrum is partly dependent on the seasons and therefore varies somewhat in the annual rhythm.
Reproduction
After a gestation period of around 60 to 75 days, two young animals are usually born, weighing between 86 and 115 g. Raising them is the sole responsibility of the females; the males do not take part. Newborns are small and helpless, their eyes opening at two to four weeks of age. The tank also takes a few weeks to harden. They are weaned at around 50 to 60 days and reach sexual maturity between nine and a maximum of twelve months. The highest known age of a bristle armadillo was 20 years.
Systematics
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Internal systematics of the armadillos according to Gibb et al. 2015
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The bristle armadillos ( Chaetophractus ) represent a genus from the group of the armadillos (Dasypoda) and the order of the armored secondary animals (Cingulata). Within the armadillos they belong to the family of the Chlamyphoridae and to the subfamily of the Euphractinae . This is also made up of the six-banded armadillo ( Euphractus sexcinctus ) and the dwarf armadillo ( Zaedyus pichiy ). The Euphractinae are in turn to be understood as a sister group of a clade consisting of the Chlamyphorinae with the two girdle species and the Tolypeutinae with, among others, the spherical armadillos ( Tolypeutes ) and the giant armadillo ( Priodontes ). Molecular genetic studies have shown that the Chlamyphoridae split up in the Upper Eocene 37 million years ago, the Euphractinae began to diversify more strongly in the Lower Miocene . The three extant genera of Armadillo Euphractinae additionally together form the tribe of Euphractini which contains numerous other, but today extinct forms, such as the from the Oligocene proven Prozaedyus . Within the subfamily, the Euphractini stand opposite the tribe of the Eutatini , which is extinct today but was very diverse. Members of this group include armadillo forms such as Eutatus or Stenotatus . Above all, Stenotatus from the Middle Miocene was very rich in shape and comprises at least five species.
A total of two types are recognized today:
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Internal systematics of the Euphractinae according to Abba et al. 2015
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- Small bristle armadillo or white-haired armadillo ( Chaetophractus vellerosus ( Gray , 1865)); western Bolivia and northwest Argentina
- Brown-bristle armadillo or brown-haired armadillo ( Chaetophractus villosus ( Desmarest , 1804)); northern Paraguay to southern Argentina
Molecular genetic studies published in 2015 indicated that the bristle armadillos may be paraphyletic because the brown-bristle armadillo is closer to the sex-linked armadillo while the lesser bristle armadillo is closer to the dwarf armadillo. Studies carried out at the same time on skull features and special characteristics of the armor did not reveal any major differences between the small bristle armadillo and the " Andean bristle armadillo ", which was originally listed as a separate species under the scientific name Chaetophractus nationi and which is distributed from southern Peru to northern Chile . Also due to the lack of genetic differences, the “Andean bristle armadillo” was synonymous with the small bristle armadillo in 2016 .
Individual representatives of the bristle armadillos had been known in Europe since the beginning of the 19th century; Félix de Azara made a first description in his report Le Tatou Velu on the brown-bristle armadillo, which he wrote in 1801 in his collection Essais sur l'Histoire Naturelle des Quadrupèdes de la Province du Paraguay had published. The genus name Chaetophractus was only introduced in 1871 by Leopold Fitzinger , in his publication The Natural Family of the Belt Animals (Dasypodes) he used the German trivial name “ Bristle Armadill ”. Armadillo, on the other hand, comes from Spanish and means “little armored man” or “little armored man”, the word being the official name for armadillos in English and partly in Spanish today.
Tribal history
The fossil record of the bristle armadillos dates back to the Late Pliocene . The oldest finds come from Chapadmalal in the Argentine province of Buenos Aires and are between 3.2 and 4 million years old. They are assigned to the brown bristle armadillo. The first finds of the lesser bristle armadillo, which date back to the early Pleistocene at around 900,000 years ago and were discovered in Punta Hermengo near Miramar in the same province, are much more recent , although they are essentially remnants of the bone shields of the dorsal armor. Both sites are located on the edge of today's range of the bristle armadillos, but belong to the Pampas region, which can therefore be regarded as the region of origin of the genus Chaetophractus . It is assumed that Patagonia, as one of the other main habitats of this group of armadillos, was only settled after the end of the most recent ice advance of the late last glacial period around 16,000 years ago, which is indicated by the high genetic variability of the populations in this region.
threat
The meat of these animals is considered tasty, which is why they are hunted by humans. It also happens that they are persecuted because they cause damage in fields with their self-dug burrows. Nevertheless, bristle armadillos are still relatively common, only the Andean bristle armadillo is listed as threatened by the IUCN , the other two species are not yet endangered.
Individual evidence
- ↑ a b c d Mariella Superina: Biology and keeping of armadillos (Dasypodidae). University of Zurich, 2000, pp. 1–248
- ↑ a b c Paul Smith: The Xenarthra famalies Myrmecophagidae and Dasypodidae. Fauna Paraguay Handbook of the Mammals of Paraguay 2012, pp. 1-35
- ↑ a b Agustín Manuel Abba and Mariella Superina: The The 2009/2010 Armadillo Red List Assessment. Edentata 11 (2), 2010, pp. 96-114
- ↑ Mariella Superina and Loughry WJ: Life on the Half Shell: Consequences of a carapace in the Evolution of Armadillos (Xenarthra: Cingulata). Journal of Mammal Evolution 19, 2012, pp. 217-224
- ↑ a b c d 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
- ↑ therein Andrew Croft, Federico Anaya, David Auerbach, Carmala Garzione and Bruce J. MacFadden: New Data on Miocene Neotropical Provinciality from Cerdas, Bolivia. Journal of Mammal Evolution 16 (3), 2009, pp. 175-198
- ^ A b Agustín M. Abba, Guillermo H. Cassini, Guido Valverde, Marie-Ka Tilak, Sergio F. Vizcaíno, Mariella Superina and Frédéric Delsuc: Systematics of hairy armadillos and the taxonomic status of the Andean hairy armadillo (Chaetophractus nationi). Journal of Mammalogy 96 (4), 2015, pp. 673-689
- ^ IUCN SSC Anteater, Sloth and Armadillo Specialist Group: Chaetophractus vellerosus. In: IUCN: IUCN Red List of Threatened Species. Version 2016. ( [1] ), last accessed on August 17, 2016
- ↑ Leopold Joseph Fitzinger: The natural family of the belt animals (Dasypodes). Meeting reports of the methematic and natural science class of the Academy of Sciences, Vienna, Department 1 64, 1871, pp. 209–276 and 329–390
- ↑ E. Soibelzon, AA Carlini, EP Tonni and LH Soibelzon: Chaetophractus vellerosus (Mammalia: Dasypodidae) in the Ensenadan (Early-Middle Pleistocene) of the Southeastern Pampean Region (Argentina) - Paleozoogeographical and Paleoclimatic Aspects. New Yearbook for Geology and Paleontology, Monthly Issues 12, 2006, pp. 734–748
- ↑ Sebastián Poljak, Viviana Confalonieri, Mariana Fasanella, Magalí Gabrielli and Marta Susana Lizarralde: Phylogeography of the armadillo Chaetophractus villosus (Dasypodidae Xenarthra): Post-glacial range expansion from Pampas to Patagonia (Argentina). Molecular Phylogenetics and Evolution 55 (1), pp. 38-46
