Chilean mouse-eared mouse
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Chilean mouse-eared mouse ( Myotis chiloensis ); Plate from the first description from 1838 |
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| ( Waterhouse , 1838) |
The Chilean mouse-eared mouse ( Myotis chiloensis ) is a species of bats (Chiroptera) belonging to the genus of the mouse-eared ( Myotis ). It lives in the southern parts of Argentina and Chile and, together with the southern brown big- eared bat ( Histiotus magellanicus ), which also occurs in Chile, is the southernmost bat in the world. Like other bats, it is nocturnal and feeds on insects in forest areas, which it catches in flight.
Charles Darwin had caught specimens of these animals in the Chiloé Archipelago and then (1837) donated them to the Zoological Society of London together with all other mammals and birds collected during his trip with the HMS Beagle . There the Chilean mouse-eared mouse was scientifically described for the first time by the British zoologist George Robert Waterhouse .
features
general characteristics
The Chilean mouse-eared mouse is a small type of mouse-eared mouse and reaches a total length of about 7.0 to 9.0 centimeters, of which the head-trunk length is 4.3 to 5.0 centimeters and the tail length 2.8 to 3 , 8 centimeters; the weight is about 6.0 to 7.5 grams. The mean hind foot length is 6.5 to 8.5 millimeters, the ear length 9.5 to 14.5 millimeters with a tragus about 4.5 millimeters in length. It is characterized by its very dark fur, which distinguishes it from other species of the genus. The specific coat color varies regionally depending on the degree of solar radiation and rainfall. In the north the animals are pale ocher, in central Chile pale brown and in the south coffee brown. The hair is two-tone with a dark gray-brown to pale brown base and a light tip, the hair is about four millimeters long. The tail membrane ( uropatagium ) has very short and soft hair, the hair does not reach the knees and the edge of the flight membrane. The tail is fully integrated into the V-shaped tail flight skin.
The wings are easy to control and designed for slow flight over a comparatively obstacle-rich route for hunting animals in the forest. The forearms reach a length of about 37 to 40 millimeters, the fifth finger is each about 47 millimeters long. When measuring the wings, a mean wingspan of 23.7 centimeters and a mean total wing area of 98 square centimeters were also determined. Compared to fast-flying bat species such as the Mexican bulldog bat ( Tadarida brasiliensis ), the tail-flight skin makes up a relatively large proportion of the total wing area, while the proportion of the arm-flight skin is correspondingly smaller. The stretching of the wings is an average of 5.8 and the surface load an average of 6.8 N / m. Due to these relatively low values for the wing extension and loading, the flight itself is energy-consuming and comparatively slow.
In its range, the Chilean mouse-eared mouse-ear occurs sympatric with three other species of the genus, the Atacama-mouse-eared ( Myotis atacamensis ) in the north of Chile and the Argentine mouse- eared mouse ( Myotis aelleni ) and the Dinnell-mouse-eared ( Myotis dinellii ) in Argentina. The species differs from the Atacama mouse-ear by its darker fur and on average slightly longer forearms. The Argentine mouse-eared mouse-ear has three-colored back hair and slightly longer forearms than the Chilean mouse-eared mouse-ear, and the Dinnell's mouse-eared mouse-ear has a very pale and hairy tail flight membrane, which in the Chilean mouse-eared mouse-ear is monochrome, dark and hairless on the edge.
Features of the skull and genome
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The skull of the species is flat and has a total length of about 14.4 millimeters and a width in the area of the zygomatic arches of about 9.1 millimeters. The ratio of the length of the skull to the total skull is pretty much exactly 2: 1 and the rostrum is about the same length as the skull area. The animals have two well-developed incisors per half in the upper jaw , followed by a canine and, behind a narrow diastema , three premolars and three molars . In the lower jaw the animals have an additional incisor per half, otherwise the teeth correspond to those in the upper jaw. Overall, the animals have a set of 38 teeth, which is the highest number of teeth in bats.
The genome of the species consists of a diploid chromosome set of 2n = 44 chromosomes (FN = 50). The X chromosome is submetacentric.
Calls
Like other bats, the Chilean mouse-eared mouse utters calls for echolocation . The call consists of two sequences, the first of which begins with a high frequency and then decreases, followed by a sequence with a very even (quasi-constant) frequency in the lower range. The page calls consist of a very short signal lasting less than four milliseconds . They start at around 89 kHz and decrease to 39 kHz, with the highest intensity of around 39 decibels at 47 kHz. The calls are emitted at approximately 95 millisecond intervals. In the area of distribution, the reputation is similar in structure to that of other smooth-nosed people . The Chilean mouse-eared mouse was compared primarily with Histiotus montanus and Lasiurus varius ; the calls of the species differ from one another mainly in the frequencies and the duration of the calls.
distribution
The Chilean mouse-eared mouse is common in the southern part of South America in Chile and Argentina . In Chile, the distribution area extends from Coquimbo at about 30 ° south latitude to the northern part of the island of Navarino in the Chilean Tierra del Fuego at about 55 ° south latitude. Together with the southern brown big- eared bat ( Histiotus magellanicus ), which also lives in Chile and Argentina, it is the most southerly common bat in the world, and in the south of Chile it is also the most common species of bats. In Argentina, it is found in the provinces of Neuquén , Río Negro , Chubut and Tierra del Fuego .
Way of life
The Chilean mouse-eared mouse lives in wooded regions of the hard foliage vegetation of central Chile up to the forests of the temperate climate in the southern part of the distribution area. To the north, the area is probably limited by the increasing aridity of the steppe and desert areas, where the species is replaced by the Atacama mouse-eared mouse. It belongs to the most widespread and at the same time most common species in the region and occurs in very diverse habitats. In parts of Chile, the bat also uses artificial forests with plants that are atypical for South America, such as pines ( Pinus ) or eucalyptus , and they live on and in houses and other structures such as bridges. Unlike other bats, the Chilean mouse-eared mouse not only uses the forest edge of commercial pine plantations, but also hunts for prey in the forests.
Like most bats, the animals are nocturnal and feed on insects, mainly mosquitoes and flies, which they catch in flight. They hunt mainly in dense beech forests ( Nothofagus ) and other forest habitats. The animals fly out at dusk and then hunt for about three hours before retreating. Unlike other insectivorous bats, they do not fly out a second time at dawn. The animals form colonies and live in caves, crevices, tree hollows and also in buildings made by people. They can also be found in the same roosting place with other species, often with the Mexican bulldog bat , the brown big-eared bat ( Histiotus macrotus ) and the southern brown big-eared bat ( Histiotus magellanicus ).
There is hardly any data on reproductive behavior and development. Like other smooth noses , they only have one reproductive cycle per year, so they are mono-estic. The females reach sexual maturity and the first gestation period at the end of their first year of life at around ten months. The females carry a single embryo , which, like other bats, develops in the right uterine horn. The cub is born at the beginning of summer. A fetus with a head-to-trunk length of 15 millimeters was found in a caught bat . There is also only very limited data available on predators and parasites . In an analysis of rabies strains and the spread of the rabies virus in Chile, bats were identified as the main reservoir, whereby this applies not only to the Chilean mouse- eared bat, but especially to the Mexican bulldog bat.
Systematics
The Chilean mouse-eared mouse is assigned to the mouse-eared species (genus Myotis ) as an independent species . The first scientific description was made by George Robert Waterhouse in 1838, who described the species as Vespertilio Chiloensis using individuals from the Chiloé archipelago . The animals came from the collection of Charles Darwin from his voyage on the HMS Beagle and were described in the multi-part work The Zoology of the Voyage of HMS Beagle, edited by Waterhouse, in the second volume on mammals , which was published under his supervision . The assignment to the mouse ears was made by Édouard Louis Trouessart in 1904.
No subspecies are currently distinguished within the species, but in the past several subspecies were considered in Chile and Argentina. Formerly as subspecies were also the Atacama mouse ear ( Myotis atacamensis ) and the mountain mouse ear ( Myotis oxyotus ), which are now regarded as separate species, however, might be the Argentine mouse ear ( Myotis aelleni ) of the type to be struck. For further clarification of the system, further research is required, especially on a genetic and molecular biological basis, since the previous distinction has primarily been made on a morphological basis and is limited due to the sometimes very small differences between the species.
The Chilean mouse-eared fossil is found in several deposits from the Holocene in the province of Chubut on the Río Chubut in Patagonia , Argentina.
Hazard and protection
The species is classified by the International Union for Conservation of Nature and Natural Resources (IUCN) as not endangered ("least concern"). No specific population size is available, but the species is considered common and threats to the species population are unknown.
supporting documents
- ^ Adrian Desmond, James Moore: Darwin . List Verlag, Munich Leipzig 1991, p. 240. ISBN 3-471-77338-X
- ↑ a b c d e f g h i j k l m n o p Gonzalo Ossa, Annia Rodríguez-San Pedro: Myotis chiloensis (Chiroptera: Vespertilionidae) . In: Mammalian Species . tape 47 (922) , 2015, pp. 51-56 , doi : 10.1093 / mspecies / sev005 ( abstract ).
- ↑ Mauricio Canals, José Iriarte-Díaz, Ricardo Olivares, Fernando Novoa: Comparación de la morfología alar de Tadarida brasiliensis (Chiroptera: Molossidae) y Myotis chiloensis (Chiroptera: Vespertilionidae), representantes de dos diferentes patrones de vuelo. Revista Chilena de Historia Natural 74 (3), 2001. doi : 10.4067 / S0716-078X2001000300015 .
- ^ A b Mauricio Canals, Bruno Grossi, José Iriarte-Díaz, Claudio Veloso: Biomechanical and ecological relationships of wing morphology of eight Chilean bats. Revista Chilena de Historia Natural 78, 2005; Pp. 215-227. ( Full text )
- ↑ a b c José Iriarte-Díaz, F. Fernado Novoa, Mauricio Canals: Biomechanic consequences of differences in wing morphology between Tadarida brasiliensis and Myotis chiloensis. Acta Theriologica 47 (2), June 2002; Pp. 193-200. doi : 10.1007 / BF03192459
- ↑ a b c A. Rodríguez-San Pedro, JA Simonetti: Acoustic identification of four species of bats (Order Chiroptera) in central Chile. Bioacoustics 22, 2013; Pp. 165-172. doi : 10.1080 / 09524622.2013.763384
- ↑ Gonzalo Ossa, José Tomás Ibarra, Kathrin Barboza, Felipe Hernández, Nicolás Gálvez, Jerry Laker and Cristián Bonacic: Analysis of the echolocation calls and morphometry of a population of Myotis chiloensis (Waterhouse, 1838) from the southern Chilean temperate forest. Cienca e Investigación Agraria 37 (2), 2010, pp. 131-139 ( [1] )
- ↑ Distribution map according to IUCN; Retrieved January 25, 2016.
- ↑ a b Myotis chiloensis in the IUCN Red List of Threatened Species 2012.2. Posted by: R. Barquez, M. Diaz, 2008. Retrieved January 13, 2016.
- ↑ Annia Rodríguez-San Pedro, Javier A. Simonetti: Foraging Activity by Bats in a Fragmented Landscape Dominated by Exotic Pine Plantations in Central Chile. Acta Chiropterologica 15 (2), 2013; Pp. 393-398. doi : 10.3161 / 150811013X679017 .
- ↑ V. Yung, M. Favi and J. Fernandez: Typing of the rabies virus in Chile, 2002-2008. Epidemiology & Infection 140 (12), December 2012; Pp. 2157-2162. doi : 10.1017 / S0950268812000520
- ↑ a b c Don E. Wilson & DeeAnn M. Reeder (eds.): Myotis chiloensis ( Memento of the original from January 16, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. in Mammal Species of the World. A Taxonomic and Geographic Reference (3rd ed).
- ^ George Robert Waterhouse: The Zoology of the voyage on the HMS Beagle under the command of captain Fitzroy, RN during the years 1832 to 1836. Part II: Mammalia. (edited by Charles Darwin) Smith, Elder & Co., London, 1838, pp. 1–97 (pp. 5–6) ( [2] )
- ↑ Daniel E. Udrizar Sauthier, Pablo Teta, Anahi E. Formoso, Ulyses FJ Pardiñas, Adela Bernardis, Patricio Wallace: Bats at the end of the world: new distributional data and fossil records from Patagonia, Argentina. Mammalia: International Journal of the Systematics, Biology & Ecology of Mammals 77 (3), August 2013; Pp. 307-315. doi : 10.1515 / mammalia-2012-0085 .
literature
- Gonzalo Ossa, Annia Rodríguez-San Pedro: Myotis chiloensis (Chiroptera: Vespertilionidae) . In: Mammalian Species . tape 47 (922) , 2015, pp. 51-56 , doi : 10.1093 / mspecies / sev005 ( abstract ).
Web links
- Myotis chiloensis inthe IUCN 2012 Red List of Threatened Species . Posted by: R. Barquez, M. Diaz, 2008. Retrieved January 13, 2016.
