Rosenberg monitor lizard
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Rosenberg monitor lizard ( Varanus rosenbergi ) |
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| Varanus rosenbergi | ||||||||||||
| Mertens , 1957 |
The Rosenberg monitor lizard or Rosenberg monitor lizard ( Varanus rosenbergi ) is a species of scale reptiles from the genus of monitor lizards ( Varanus ) endemic to Australia . It was first described in 1957 by the German herpetologist Robert Mertens . The species epithet honors the German naturalist , geographer and zoologist Hermann von Rosenberg . The Rosenberg monitor lizard is one of the best-researched Australian monitor lizard species.
description
The Rosenberg monitor lizard can be up to 150 cm long, whereby the specimens living on the Australian mainland are generally smaller than the animals on the offshore islands. The length of the tail is 1.3 to 1.8 times the length of the head and torso . The back of the animals is dark. The belly side is light from the chin to the abdomen and covered with a dark mesh or stripe pattern. The head is black with light spots and has a black temple stripe with light edges. The scales of the head are smooth and small. The nostril is on the side and closer to the tip of the snout than to the eye. The neck and trunk are characterized by about 15 narrow, close, black horizontal stripes on a brownish background. The tail shows brownish horizontal stripes on a black background. The tip of the tail is either also striped or solid black. The tail root is cylindrical, the rear part of the tail is relatively strongly flattened laterally. The body has 160 to 210 scale rows.
distribution
The Rosenberg monitor lizard occurs exclusively in Australia. Its distribution area extends there in a relatively narrow strip along the coast, from the southwest of Western Australia to the southeast of South Australia . Isolated populations exist in Victoria and New South Wales . Also some islands off the coast of southern Australia, e.g. B. Kangaroo and Reevesby Island , are inhabited by the Rosenberg monitor lizard. Presumably it was deliberately released on some islands in order to decimate the snakes there .
Except on Kangaroo Island , the Rosenberg monitor lizard is generally rare.
Way of life
The Rosenberg monitor lizard owes its common English name “heath goanna” (bush monitor) to the fact that it lives in the bush near the coast. But it also occurs in tree-covered and wooded areas.
The animals are diurnal and usually retreat to a shelter one to two hours before sunset. This can be a cave in the earth, a hollow tree stump or a crevice. An individual usually has several such shelters within his territory. Since the territories of different animals overlap, it can happen that the same shelter is used by different animals on different nights. It is rather unusual for more than one animal to spend the night in a shelter. The animals often dig the caves themselves, but also use burrows that have been dug by individuals of other species.
Reproduction
The Rosenberg monitor lizard reaches sexual maturity at two to three years of age. The mating season is in midsummer, from late December to early February. The mating takes place in the territory of the female and in rare cases can drag on for up to three weeks, with several copulations per day, whereby the male only begins to copulate after a few days of close contact with the female. The eggs are laid between the end of January and the beginning of March.
In the wild, the animals prefer populated termite burrows of the species Nasutitermes exitiosus to lay their eggs . The female digs a hole in the wall of the termite den, creates a kind of chamber and lays her eggs there. The termites then close the hole . The eggs are extremely well protected from enemies. In addition, the temperature and humidity inside a termite den is always constant (in winter no less than 20 ° C, with outside temperatures below 15 ° C), which offers the eggs and the newly hatched young optimal development conditions. After laying eggs, the female stays near the nest for a few weeks so that it can protect its clutch in an emergency. In September or October, the young burrow through the wall outside. It is very likely that they will not receive any help from one of the parent animals, as is described for the spotted monitor ( Varanus varius ). The young animal remains in the termite burrow until the outside temperatures are sufficiently high and feeds on the termites during this time. It also uses the building as a shelter for the night for a few months afterwards.
food
Like most monitor lizards, the Rosenberg monitor lizard is a hunter. He is not picky and eats beetles and cockroaches as well as small terrestrial vertebrates, mainly mammals and reptiles. He also plunders clutches of reptiles. In one case, a Rosenberg monitor lizard was seen capturing a young short-billed hedgehog ( Tachyglossus aculeatus ). Occasionally Rosenberg monitor lizards also eat carrion , for example animals run over on the street.
Systematics
The German Robert Mertens described the species as a subspecies of the Gould monitor lizard ( Varanus gouldii ) in 1957 . The Australian Glen Milton Storr later raised this subspecies to species status because he determined that there are no hybrids of these species to be found in the regions where the Rosenberg and Gould monitor lizard occur sympatric . Outwardly, Rosenberg and Gould monitor lizards are very similar, but they differ in that the latter has a single-colored, light-colored tail tip and a slightly different pattern on the abdomen.
Since the representatives of the isolated populations in the east of the distribution area have significantly longer tails than the representatives of the western population, it is assumed that both populations are separate species.
Within the lizards (genus Varanus ) of the Rosenberg's Monitor is in the subgenus Varanus (Varanus) and within this to the gouldii provided -Artgruppe.
literature
- Dennis R. King, Ruth Allen King: Varanus rosenbergi. In: Eric R. Pianka, Dennis R. King, Ruth Allen King (Eds.): Varanoid Lizards of the World. Indiana University Press, Bloomington (IN) 2004, pp. 225-229.
Web links
- Rosenberg monitor lizard in the IUCN Red List of Threatened Species
- Rosenberg-Waran on Monitor-Lizards.net ( English version )
- Rosenberg monitor lizard on monitor world
- Rosenberg Monitor Lizard in the Australian Reptile Online Database
- Rosenberg monitor lizard on Mampam Conservation
- Rosenberg monitor profile on the official website of New South Wales
- Varanus rosenbergi in The Reptile Database
Individual evidence
- ↑ Varanus rosenbergi - Heath Goanna. Adelaide and Mount Lofty Ranges, South Australia, Threatened Species Profile. Biodiversity Conservation Unit, Adelaide Region, Department for Environment and Heritage, 2008 ( PDF 293 kB)
- ↑ Peggy D. Rismiller, Michael W. McKelvey, Brian Green: Breeding Phenology and Behavior of Rosenberg's Goanna ( Varanus rosenbergi ) on Kangaroo Island, South Australia. Journal of Herpetology. Vol. 44, No. 3, 2010, pp. 399–408, doi : 10.1670 / 09-066.1 (alternative full text access : echidna.edu )
- ↑ Paragraph mostly based on Brian Green, Michael W. McKelvey, Peggy D. Rismiller: Behavior and Energetics of Hatchling Varanus rosenbergi. In: H.-G. Horn, W. Böhme (Ed.): Advances in Monitor Research II. Mertensiella. Vol. 11, 1999, pp. 105–112 ( PDF 503 kB)
- ^ A b G. M. Storr: The Monitor Lizards (Genus Varanus Merrem, 1820) of Western Australia. Records of the West Australian Museum. Vol. 8, No. 2, 1980, pp. 237-293 ( online )
- ^ D. Bennett, SS Sweet: Varanus rosenbergi. The IUCN Red List of Threatened Species. Version 2014.2. (Data set created 2010). Accessed August 1, 2014.