Cretan frog
Crete - water frog ( Pelophylax cretensis )
The Crete - water frog ( Rana Pelophylax cretensis or cretensis ) is within the order of Anura to the family of the Real frogs ( Ranidae ). In addition, he is expected to follow appearance, biology and distribution of the water frogs, which are now provided by many authors in a separate genus Pelophylax. The species is endemic native to the Greek Mediterranean island of Crete.
Features
It is a medium-sized water frog, with males apparently remain significantly smaller than the females. While this in an investigation, East Crete head-body length of about 52 to 86 mm had (arithmetic mean: 67.6 ), reached the local males only sizes 40.5 to 61 mm (mean: 53.2 ). Males were 8-31 grams, females 20-96 grams.
The top is beige with shimmer olive or brown - gray, less often green with large brown or olive-green, irregular patches. Some animals exhibit signs of a yellowish dorsal midline, but never quite consistently. Belly and throat are whitish or ivory, occasionally with weak Graupigmentierung. The insides of the legs and the flanks are interspersed with yellow coloring, this is particularly intense in the axillary region. The hock is slightly rounded, with adolescent animals also flat and triangular - similar to Central European Seefröschen. The males have paired vocal sacs, which can be dark gray, dark green or almost black.
Distribution and habitat
The Crete - water frog is found only on the Greek island of Crete, where he mainly populated lowland regions. The highest locality is located at Skinias in the southeast to 214 m above sea level. Most resources exist in the western island area.
The species seems mainly to colonize oxygen-rich streams and rivers, but in addition also reservoirs and artificial ponds. Young animals are also found in small water holes and flooded banks. Contaminated waters, as they are numerous in Crete, apparently shunned.
The animals are very shy and flee when disturbed immediately into the water where they hide under rocks or in mud. The call activity of the males ( the spawning season begins approximately in February ) is in the late evening and night hours at the most. This could also be related to a high predation pressure; for example, come in many habitats such as sea turtles Mauremys caspica still very numerous.
System
The Crete - water frog belongs to the complex shape of the water frogs ( Pelophylax ), which is systematically not yet completely processed and is difficult to detect due to the many generations of hybrids. More closely related and recognized water frog species on the southern Balkan Peninsula including the Mediterranean islands of Epirus Water Frog ( Pelophylax epeiroticus ) and the Skadar water frog ( P. shqipericus ). The Karpathos Frog ( P. cerigensis ) is called the shape with unclear status. In Southwest Asia also occurs Bedriagas water frog ( Rana cf bedriagae ), which should also occur in Turkey, Cyprus and on several Greek islands to become dubious views.
Endangering
The Crete - water frog is classified in the red list of endangered species by the IUCN as endangered ( " Endangered " ) because it has a relatively small area of distribution of less than 500 km ², and this is highly fragmented. Moreover, a growing deterioration of its habitat is found. The main threat to this species extends from the loss of suitable habitats by agriculture, tourism and the colonization of their habitat. The water of the rivers is necessary for them to irrigate agricultural land, especially for growing bananas, used. This eliminates many rivers dry during the summer. An additional hazard represents the introduced North American bullfrogs (Rana catesbeiana or Lithobates catebeianus ), which competes with the smaller Crete - water frog to protect the habitat and this threatened by predation.