Robust cottontail
Sylvilagus robustus is a species of mammal of the genus cottontail rabbit among lagomorphs. Its distribution area originally comprised individual mountain ranges in New Mexico, Texas and in the State of Coahuila, Mexico. The current area of distribution, however, is probably limited to the Davis Mountains in Texas, while the species is extinct in most other regions. The remaining stocks appear to be very sensitive to drought, in addition, there are other hazards caused by habitat destruction. Sylvilagus robustus is classified by the International Union for Conservation of Nature and Natural Resources ( IUCN) as threatened ( endangered ).
Features
Sylvilagus robustus corresponds in size and appearance to the Florida Cottontail ( Sylvilagus floridanus ), as its subspecies, it was originally considered. It is a medium -sized species of its genus with a snout-vent length from 37.5 to 46.3 inches. From Florida Cottontail it can be clearly distinguished only by different skull dimensions and characteristics of the teeth.
Dissemination
Originally, the rabbits in the Guadalupe Mountains was in Texas and New Mexico, the Chisos Mountains and the Davis Mountains in Texas and the Sierra de la Madera in the state of Coahuila, Mexico to meet. In the Guadalupe Mountains, the Chisos Mountains in Mexico and the kind now considered extinct, Sylvilagus robustus is now probably only in the Davis Mountains in Texas before. An occurrence of cottontail rabbits to give in Mexico in the Sierra del Carmen, but it is unclear what kind it is. 2012 reported Nalls et al. however, that they have collected and identified individuals of the species in the Chisos Mountauns and therefore, except in the Davis Mountains still exists a second occurrence.
The altitudinal distribution of Sylvilagus robustus gets that far known only above 1,500 meters and is only about 1,800 meters frequently. When only considering altitudes above 1675 meters, the available area is that of the type preferred vegetation in the Davis Mountains about 730 square kilometers.
Way of life
Over the life of Sylvilagus robustus are very few information. Its habitat is the Madrean Pine - Oak Woodlands, subtropical and evergreen forest areas. It is believed that his way of life of the Florida forest rabbit is very similar.
System
Sylvilagus robustus is assigned as an independent species the cottontail rabbits ( genus Sylvilagus ). Originally, it was considered a subspecies of the Florida Forest rabbit ( Sylvilagus floridanus ). Ruedas 1998 demonstrated that S. robustus, like Sylvilagus cognatus distinct species of the genus by morphological comparisons of the skull and teeth of various subspecies of Florida cottontail. 2010 confirmed Lee et al. the independence of the species by molecular biological studies.
Within the species, no subspecies are distinguished.
Threats and conservation
Sylvilagus robustus is classified by the International Union for Conservation of Nature and Natural Resources ( IUCN) as threatened ( endangered ). Originally, the type of several mountain ranges is known today she lives probably only in the Davis Mountains and is extinct in the other regions, and since the 1960s, no living individuals in these areas were detected. In the 1970s, were two unconfirmed sightings in the Guadalupe Mountains. The last record from the Davis Mountains, one killed on a street animal, dates from 1997 and was the first evidence after 20 years.
The total area of the remaining distribution area in the Davis Mountains is only about 1,815 square kilometers, where the usable area for the rabbit is probably only about 730 square kilometers. Due to droughts and other influences there can be large fluctuations in the numbers of individuals and the number of viable reproductive rabbit.
The main threat to the species is based primarily on their very small number of individuals and density, which makes them very sensitive to drought and other influences. At the same time the habitat decreases by habitat destruction due to urbanization and the expansion of grazing areas.