Dwarf armadillo

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Dwarf armadillo
Pygmy armadillo (Zaedyus pichiy)

Pygmy armadillo ( Zaedyus pichiy )

Systematics
Order : Armored siderails (Cingulata)
without rank: Armadillos (Dasypoda)
Family : Chlamyphoridae
Subfamily : Euphractinae
Genre : Zaedyus
Type : Dwarf armadillo
Scientific name of the  genus
Zaedyus
Ameghino , 1889
Scientific name of the  species
Zaedyus pichiy
( Desmarest , 1804)

The dwarf armadillo or pichi ( Zaedyus pichiy ) is a species of mammal from the group of armadillos (Dasypoda). Their home is southern South America . Here it lives mainly in central and southern Argentina and Chile ( Patagonia ) up to the Strait of Magellan and inhabits solitary open and dry habitats where it digs underground burrows. The dwarf armadillo is the only armadillo to hibernate and continues to reproduce in a seasonally bound manner. As an omnivore , its diet consists of both vegetable and animal food. The widespread distribution means that the population of the dwarf armadillo is currently less threatened.

features

Habitus

The dwarf armadillo is one of the smallest armadillo species, only the belt mole are smaller. It reaches a head-trunk length of 26 to 33 cm, plus a 10 to 14 cm long tail. The weight varies from 0.75 to 2 kg, but females are on average slightly smaller than males. The head is short and triangular and has a length of around 7 cm. However, it has a long snout and small ears, only about 2 cm long. The eyes are small and have bristly hair above and below the lids. The top of the head is covered by shield plates that form a triangular head armor, which is relatively narrower than that of the bristle armadillos , especially the approximately equal sized small bristle armadillo ( Chaetophractus vellerosus ). The back armor, which is 16 to 24 cm long and 19 to 25 cm wide, measured across the curve, consists of a fixed shoulder and pelvis, which are separated by six to nine, but usually seven, movable bands in between. This armor, too, is formed from small bone shields, with those of the movable ligaments 20 mm long and 6 mm wide and divided into several parts. The plates of the rigid armor are almost square in shape with edge lengths of less than 10 mm. The labels on the edge of the tank also have a characteristic pointed tip. On the neck there is also a band of such bone formations, which individually reach around 5 mm in size, and the tail, which reaches a length of up to 13 cm, has armor. The back armor is yellowish over dark brown to almost black, but sometimes there is a lighter back line that extends from the first band to the end of the pelvic armor. The tail and belly are tinged with yellow. Dense, brownish, bristle-like hairs grow between the individual platelets, which are much thicker in winter. The limbs have five toes in front and behind with well-developed claws. The rear foot length is 4.8 cm.

Skull and skeletal features

The skull is on average 6.8 cm long and 4.2 cm wide at the zygomatic arches , and 1 cm wide in the area of ​​the rostrum . Unlike its close relatives, the bristle armadillos and the six-banded armadillo , the Pichi has the upper dentures, no teeth in the middle jawbone , but only in the upper jaw. The teeth as a whole differ from those of other mammals and are constructed without tooth enamel , whereby they have a molar-like shape. In the upper jaw there are eight, in the lower jaw nine teeth per half of the jaw, so a total of 34. Similarly, in the dwarf armadillo, analogous to its relatives, the upper ulna joint on the forelimbs is extremely large and reaches 1.9 cm in length, with a bone length of 4.6 cm. These large joints on the front legs are typical of burrowing animals.

Sensory performances and vocalizations

Several sounds are known, especially in the event of a threat, a kind of purring that can also turn into a grunt, when touched is usually followed by a squeak.

distribution

Distribution area

The distribution area is one of the most southerly of all armadillo species and extends from central Argentina over eastern Chile to the south to the Strait of Magellan , so it covers a large part of Patagonia . The dwarf armadillo occurs from sea level up to an altitude of 2500 m. The size of the distribution area is 1.3 million square kilometers, but the actually inhabited area and the density of the population are unknown. The dwarf armadillo was originally endemic to Argentina, but it spread to Chile in the 19th century. The habitat includes dry grasslands and scrubland as well as the Patagonian steppe areas and desert-like landscapes. The occurrence of this armadillo is associated with sandy or volcanic soils. In these regions there are sometimes harsh climatic conditions with annual temperatures of −15 to +35 ° C and around 320 mm of annual precipitation, which falls as snow in winter. The dwarf armadillo is sometimes found in agricultural areas.

Way of life

Territorial behavior

Pygmy armadillo in central Argentina

The pygmy armadillo is largely diurnal and lives solitary, groups only form during mating. The individual animals have action spaces ( home ranges ), which in the barren landscapes can sometimes be quite large, with those of the males possibly exceeding those of the females in size. There, the dwarf armadillo digs burrows that are several meters long and have different depths, but in winter they can reach up to 1.5 meters underground. The depth of the building reflects the ground level, at which the temperature inside the building is more or less independent of the strongly changing temperature of the earth's surface due to the thermal inertia of the soil. Special nests made of plant material are seldom created; this was only observed in one of 70 buildings examined. The entrances are designed like a dome, 15 cm wide and 8 cm high and are usually hidden under vegetation. An animal sometimes returns to the same den for several days in a row, but in the meantime also creates new ones. The dwarf armadillo is the only armadillo able to fall into hibernation, which lasts from April to August and in which the body temperature is significantly reduced to up to 15 ° C. This hibernation consists of individual rigid phases ( torpor ) that last an average of 72 hours and are interrupted by short periods of increased body temperature; it is one of the few known South American mammals, such as the Chiloé opossum , that actually hibernate. In addition, the pygmy armadillo is also capable, outside of this period, in unfavorable environmental conditions and poor food supply, in torpor lasting several hours.

nutrition

The diet of the dwarf armadillo consists of insects, worms, and small vertebrates such as lizards and rodents. Furthermore, they also consume plant-based food and mushrooms, so it is a downright omnivore , but it is more opportunistic to eat it. However, the feeding behavior of the dwarf armadillo has not yet been studied in great detail; results are largely only available for individual stocks from Argentina and relate to the summer months. At this time, an animal often eats beetles and their larvae , scarab beetles dominate here , which can make up up to 52% of the total diet. Two-winged birds also have a high proportion, with around a quarter of the total biomass eaten. It is noteworthy that the dwarf armadillo also plunders nests of real bees close to the ground , such as the genus Centris , and sometimes drags their remains into its burrows. Ants also play a major role, especially workers and soldiers of the Solenopsis genus , who make up an average of 15% of the amount eaten. Plants are of roughly the same value, including primarily grass seeds , leaves and roots , but also inflorescences, including those of Grindelia chilorensis . Mushrooms, on the other hand, are very rarely used as a food resource, as are small vertebrates or spiders . Sand is also important as a mineral supplier , which in some cases fills up to 50% of the stomach contents examined. As a rule, the pygmy armadillo does not drink water in the wild and meets its fluid needs with food. The animals of eastern Chile show a similar preference. Among the beetles dominate but running and weevils and Schröter . Furthermore, ants and grasshoppers belong to the food spectrum , as well as sweet grasses and barberries .

Reproduction

Male and female animals become sexually mature at around nine months. The mating season is seasonally bound and is usually in spring, from August to October, but there is a dependency on the geographical latitude, so that it begins the later and ends the earlier the more southerly the distribution area is. Research suggests that males only produce sperm during this time . During the mating season there can be aggression among males, which then also defend their areas. After a gestation period of around 60 days , the female usually gives birth to one to three (usually two) young animals weighing around 50 g in a burrow between October and January. Newborns have soft, pink body armor that hardens and changes color after around two weeks. The eyes open after about three weeks. The young animals leave the den for the first time after around 40 days when they are partially weaned. During the breastfeeding period, the mother often reacts aggressively to disturbances. The maximum known age of an animal in human care was nine years.

Predator and enemy behavior

In the event of a threat, the dwarf armadillo often lies down, pulls arms and legs under the body and presses the shell to the ground, so predators cannot reach the soft belly, but the rest is only partially protected by the shell because it is not hard enough and great predators can bite through it. However, it also flees into the next burrow or hides in the bushes. The most important predators include the puma , the Argentine fighting fox and the fence eagle . For the latter, the dwarf armadillo is the main prey, as studies in central Argentina show that it accounts for more than half of the biomass hunted. The blue buzzard occasionally preyes on a dwarf armadillo.

Parasites

More than 50 parasites are known to affect the dwarf armadillo. The outer ones include mainly fleas and ticks , the former are represented by the genus Malacopsylla , the latter by Amblyomma . Internal parasites usually include nematodes , including for example Cyclobulura , Trichuris and Aspidodera . Tapeworms have been detected with Mathevotaenia , and the unicellular Eimeria also occurs. A study on 53 remnants of the dwarf armadillo's faeces showed that internal parasites could be detected in up to 93% of all cases. The armadillo is also the carrier of the parasite Trypanosoma cruzi , which causes Chagas disease , and the protozoon Toxoplasma gondii, which causes toxoplasmosis . Both diseases themselves have hardly been detected in the dwarf armadillo. Infections with besnoitiosis are relatively common .

Systematics

Internal systematics of the armadillos according to Gibb et al. 2015
  Dasypoda  
  Dasypodidae  

 Dasypus


  Chlamyphoridae  
  Euphractinae  

 Euphractus


   

 Chaetophractus


  Zaedyus  

 Zaedyus pichyi




   
  Chlamyphorinae  

 Chlamyphorus


   

 Calyptophractus



  Tolypeutinae  

 Priodontes


   

 Tolypeutes


   

 Cabassous







Template: Klade / Maintenance / Style

The dwarf armadillo belongs to the genus Zaedyus and is its only species . Within the group of armadillos (Dasypoda) it is still part of the family of Chlamyphoridae and the subfamily of Euphractinae . The closest relatives of the dwarf armadillo provide the chaetophractus ( Chaetophractus ) and the six-banded armadillo ( Euphractus sexcinctus ). The total Euphractinae are available here as a sister group to a clade consisting of the Chlamyphorinae with the pink fairy armadillo and Tolypeutinae against, inter alia, the ball belt animals ( Tolypeutes ) and the bare- tailed armadillos ( Cabassous ) belong. With the help of molecular genetic investigations it was determined that the Chlamyphoridae already separated in the Upper Eocene 37 million years ago. The diversification of the Euphractinae into the genera existing today mainly took place in the late Miocene around 11 million years ago. Numerous other genera can be assigned to the subfamily fossil.

Today, two subspecies of the dwarf armadillo are distinguished:

The oldest fossil records of the genus Zaedyus come from the Pliocene . The dwarf armadillo itself can be found in fossils for the first time in the Lower Pleistocene, based on finds from the Argentine province of Buenos Aires . Significant fossil remains were found near Mar del Plata or Necochea .

Both subspecies differ in their skull features, which are smaller in the former and have a significantly shorter rostrum than the nominate form. The first description of the dwarf armadillo was in 1804 by Anselme Gaëtan Desmarest as Loricatus pichiy , this in turn was based on the description Le tatou pichiy de d'Azara by Félix de Azara from his collection Essais sur l'Histoire Naturelle des Quadrupèdes de la Province du Paraguay from 1801 The term pichiy or pichi comes from the Mapuche language and means something like "small". Already in 1782 GI Molina had named the dwarf armadillo as Dasypus quadricinctus , but the designation is invalid because it represents a younger homonym , which Linnaeus had already used in 1758 for the northern spherical armadillo ( Tolypeutes tricinctus ). Since Linnaeus used this designation for a specimen that differed only in an additional fourth, movable band, Dasypus qadricinctus is now a synonym for Tolypeutes tricinctus

Threat and protection

Dwarf armadillo

The meat of the dwarf armadillos enjoys an excellent reputation among the inhabitants of Patagonia, and accordingly it is often hunted, not only as a food resource, but also for sporting purposes. In addition, dogs are also considered a threat factor, which also pose animals. A disease that has not yet been precisely categorized, the so-called "Pichi plague", which occurs mainly during wetter periods, regularly leads to a decline in stocks in individual regions. Furthermore, individual areas inhabited by the dwarf armadillo are also grazed over by livestock . However, the low population density in its range means that the total population is less endangered than that of other armadillos and the dwarf armadillo is still common. The IUCN classifies the dwarf armadillo as " near threatened " because of this . It occurs in numerous protected areas, but rarely in zoos. In Argentina it is sometimes kept as a pet.

literature

  • Ronald M. Nowak: Walker's Mammals of the World. 2 volumes. 6th edition. Johns Hopkins University Press, Baltimore MD et al. 1999, ISBN 0-8018-5789-9 .
  • Mariella Superina, Agustín M. Abba: Zaedyus pichiy (Cingulata: Dasypodidae). In: Mammalian Species. 46 (905), 2014, pp. 1-10.
  • 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 (p. 68) ISBN 978-84-16728-08-4

Individual evidence

  1. Jump up ↑ EJ Galíndez, S. Estecondo, EB Casanave: The Spleen of Zaedyus pichiy, (Mammalia, Dasypodidae): a Light and Electron Microscopic Study. In: Anatomia, Histologia, Embryologia . 32, 2003, pp. 194-199.
  2. ↑ a b c d Mariella Superina: Natural history of the pichi (Zaedyus pichiy) in Mendoza Province, Argentina. University of New Orleans, 2007, pp. 1-156.
  3. ↑ a b Mariella Superina: Biology and keeping of armadillos (Dasypodidae). University of Zurich, 2000, pp. 1–248.
  4. ↑ a b c d e f g h i j k Mariella Superina, Agustín M. Abba: Zaedyus pichiy (Cingulata: Dasypodidae). In: Mammalian Species. 46 (905), 2014, pp. 1-10.
  5. ↑ a b c d e Mariella Superina, Agustín Manuel Abba: Chlamyphoridae (Chlamyphorid armadillos). In: Don E. Wilson, Russell A. Mittermeier (eds.): Handbook of the Mammals of the World. Volume 8: Insectivores, Sloths and Colugos. Lynx Edicions, Barcelona 2018, pp. 48-71 (p. 68) ISBN 978-84-16728-08-4 .
  6. ^ SF Vizcaíno, N. Milne: Structure and function in armadillo limbs (Mammalia: Xenarthra: Dasypodidae). In: Journal of Zoology. 257, 2002, pp. 117-127.
  7. ↑ a b Mariella Superina: The natural history of the pichi, Zaedyus pichiy in western Argentinia. In: Sergio F. Vizcaíno, WJ Loughry (Ed.): The Biology of the Xenarthra. University Press of Florida, 2008, pp. 313-318.
  8. ↑ M. Superina, Agustín. M. Abba: Zaedyus pichiy. In: Edentata. 11 (2), 2010, p. 178.
  9. ↑ Agustín M. Abba, Marcela J. Nabte, Daniel E. Udrizar Sauthier: New Data on Armadillos (Xenarthra: Dasypodidae) for Central Patagonia, Argentina. In: Edentata. 11 (1), 2010, pp. 11-17.
  10. ↑ a b M. Superina, F. Fernández Campón, EL Stevani, R. Carrara: Summer diet of the pichi Zaedyus pichiy (Xenarthra: Dasypodidae) in Mendoza Province, Argentina. In: Journal of Arid Environments. 73, 2009, pp. 683-686.
  11. ↑ a b Mariella Superina, Patrice Boily: Hibernation and daily torpor in to armadillo, the pichi (Zaedyus pichiy). In: Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology. 148 (4), 2007, pp. 893-898.
  12. ↑ Mariella Superina, Graciela A. Jahn: Effect of low-quality diet on torpor frequency and depth in the pichi Zaedyus pichiy (Xenarthra, Dasypodidae), a South American armadillo. In: Journal of Thermal Biology. 38, 2013, pp. 280-285.
  13. ↑ Laura C. Sarzetti, Jorge F. Genise: Predation of Soil-Nesting Centris muralis (Insecta: Apidae) by Armadillos (Zaedyus pichiy) (Mammalia: Cingulata) in La Rioja Province, Northwestern Argentina. In: Journal of the Kansas Entomological Society. 84 (3), 2011, pp. 179-183.
  14. ↑ Aldo Arriagada, Luisa Baessolo, Cristián Saucedo, Julio E. Crespo, Julio Cerda, Luis Parra, Dennis Aldridge, Jaime Ojeda and Alex Hernández: Hábitos alimenticios de poblaciones periféricas de Zaedyus pichiy y Chaetophractus chamypulagoniae, chlamypulidae en . In: Iheringia. Série Zoologia. 107, 2017, p. E2017013, doi: 10.1590 / 1678-4766e2017013 .
  15. ↑ Mariella Superina, WJ Loughry: Life on the Half Shell: Consequences of a carapace in the Evolution of Armadillos (Xenarthra: Cingulata). In: Journal of Mammal Evolution. 19, 2012, pp. 217-224.
  16. ↑ Mariella Superina, Graciela A. Jahn: Seasonal reproduction in male pichis Zaedyus pichiy (Xenarthra: Dasypodidae) estimated by fecal androgen metabolites and testicular histology. In: Animal Reproduction Science. 112, 2009, pp. 283-292.
  17. ↑ José Hernán Sarasola, Miguel Ángel Santillán, Maximiliano Adrián Galmes: Crowned eagles rarely prey on livestock incentral Argentina: persecution is not justified. In: Endangered Species Research. 11, 2010, pp. 207-213.
  18. ↑ a b Mariella Superina, Michael M. Garner, Roberto F. Aguilar: Health evaluation of free ranging and captive pichis (Zaedyus pichiy; mammals, Dasypodidae) in Mendoza Province, Argentinia. In: Journal of Wildlife Diseases. 45 (1), 2009, pp. 174-183.
  19. ↑ D. Saggese: live mammal prey (Zaedyus pichiy) in a nest of af the Black-chested Buttard-Eagle (Geranoaetus melanoleucus). In: Journal of Raptor Research. 38 (1), 2004, pp. 101-102.
  20. ↑ Marcela Lareschi, Juliana P. Sanchez, M. Cecilia Ezquiaga, Analía G. Autino, M. Mónica Díaz, Rubén M. Barquez: Fleas Associated with Mammals from Northwestern Argentina, with New Distributional Reports. In: Comparative Parasitology. 77 (2), 2010, pp. 207-213.
  21. Jump up ↑ Graciela T. Navone, María C. Ezquiaga, Juliana Notarnicola, F. Agustín Jiménez: A New Species of Cyclobulura (Nematoda: Subuluridae) from Zaedyus pichiy and Chaetophractus vellerosus (Xenarthra: Dasypodidae) in Argentina. In: Journal of Parasitology. 96 (6), 2010, pp. 1191-1196.
  22. ↑ M. Cecilia Ezquiaga, Mariella Superina, Graciela T. Navone: Parásitos intestinales de Zaedyus pichiy (Xenarthra: Dasypodidae) de Mendoza, Argentina. In: Mastozoología Neotropical. 16 (2), 2009, pp. 309-319.
  23. ↑ a b Gillian C. Gibb, Fabien L. Condamine, Melanie Kuch, Jacob Enk, Nadia Moraes-Barros, Mariella Superina, Hendrik N. Poinar, Frédéric Delsuc: Shotgun Mitogenomics Provides a Reference Framework Phylogenetic and Time Scale for Living Xenarthrans. In: Molecular Biology and Evolution. 33 (3), 2015, pp. 621–642.
  24. ↑ Maren Möller-Krull, Frédéric Delsuc, Gennady Churakov, Claudia Marker, Mariella Superina, Jürgen Brosius, Emmanuel JP Douzery, Jürgen Schmitz: Retroposed Elements and Their Flanking Regions Resolve the Evolutionary History of Xenarthran Mammals (Armadillos, Anteaters and Sloths). In: Molecular Biology and Evolution. 24, 2007, pp. 2573-2582.
  25. ↑ Frédéric Delsuc, Mariella Superina, Marie-Ka Tilak, Emmanuel JP Douzery, Alexandre Hassanin: Molecular phylogenetics unveils the ancient evolutionary origins of the enigmatic fairy armadillos. In: Molecular Phylogenetics and Evolution. 62, 2012, pp. 673-680.
  26. ^ A b Alfred L. Gardner: Mammals of South America, Volume 1: Marsupials, Xenarthrans, Shrews, and Bats. University of Chicago Press, 2008, ISBN 978-0-226-28240-4 , pp. 146-148.
  27. ↑ Esteban Soibelzon, Ángel Ramón Miño-Boilini, Alfredo Eduardo Zurita, Cecilia Mariana Krmpotic: Los Xenarthra (Mammalia) del Ensenadense (Pleistoceno inferior a medio) de la Región Pampeana (Argentina). In: Revista Mexicana de Ciencias Geológicas. 27 (3), 2010, pp. 449-469.
  28. ↑ Oldfield Thomas: The mammals of the tenth edition of Linnaeus; an attempt to fix the types of the genera and the exact bases and localities of the species. In: Proceedings of the Zoological Society of London. 1911, pp. 120-158.
  29. ↑ Mariella Superina, Agustín M. Abba: Zaedyus pichiy. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. ( [1] ), last accessed on April 20, 2013

Web links

Commons : Zaedyus pichiy  - collection of images, videos and audio files