Potamon potamios
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| ( Olivier , 1804) |
Potamon potamios is a local crayfish from the family of Potamidae . Several subspecies have been described.
features
Potamon potamios is a relatively large freshwater crab , depending on the subspecies , its carapace reaches a width of about 55 to 70 mm, a length of 44 to 57 mm and a height of 26 to 34 mm. The carapace is slightly arched, smooth and shiny. Its front lateral edge has numerous very small, rounded teeth. The forehead is strongly sloping and has two smooth, shiny lobes with a granular top. The crista is sharp up to the flat, S-shaped cervical furrow and then broken up into grains. The abdomen of the males is elongated triangular with slightly convex sides, the abdomen of the females is wider, as with all crabs.
The two scissors are relatively large and can be slightly different. They have high cutting edges that leave a gap when they close and are alternately set with a larger and three to four smaller knots. Carpus and merus are rough on the outside due to scale-like pustules. The legs are stocky.
The first gonopods of the males have a conically elongated end member that is slightly bent outward in the middle area. The next link is long and slightly curved. The flexible area between these two limbs is noticeably bilobed. The gonopods serve as distinguishing features to the other species of the genus.
distribution and habitat
The species is widespread in the eastern Mediterranean, but is very fragmented . Their natural habitat is in the fresh waters of the Mediterranean islands of Rhodes, Naxos , Karpathos , Crete and Cyprus , in Turkey, Syria, Jordan, Lebanon, Israel (including the Palestinian territories of Gaza and the West Bank) and Egypt ( Sinai Peninsula ). In Greece Turkey the distribution areas of the four very similar species Potamon potamios , Potamon ibericum , Potamon fluviatile and Potamon rhodium overlap .
Way of life
Potamon potamios lives in lakes and rivers. A threat to its habitats comes from humans. More and more springs are enclosed and diverted in the rather dry areas of the eastern Mediterranean for water extraction. Potamon potamios is considered to be semiterrestrial, it also occurs in semi-arid climates . While the medium-sized specimens leave the water at night to look for food, larger ones are also active during the day and can be observed both in the water and on the banks.
Systematics
Potamon potamios belongs within the family of the Potamidae to the subfamily Potaminae , whose range extends from Europe and North Africa to North India and Myanmar . Within the genus Potamon is potamon potamios to Nominat-subgenus Potamon counted, so Potamon (Potamon) potamios .
Subspecies
Due to the disjoint distribution in areas far from each other and isolation on islands, the gene pool of this species was poorly mixed , so that numerous subspecies could develop. Seven subspecies are currently considered valid:
- Potamon potamios ssp. cyprion Pretzmann , 1962
- Potamon potamios ssp. karamani Pretzmann, 1962
- Potamon potamios ssp. karpathos Ghiavarini, 1934
- Potamon potamios ssp. Crete Ghiavarini, 1934
- Potamon potamios ssp. palaestinense Bott, 1967
- Potamon potamios ssp. potamios (Olivier, 1804)
- Potamon potamios ssp. schoenmanni Pretzmann, 1986 (island of Naxos)
Individual evidence
- ^ D. Brandis, V. Storch, M. Türkay: Taxonomy and zoogeography of the freshwater crabs of Europe, North Africa and the Middle East . In: Senckenbergiana biologica . tape 80 , no. 1/2 , 2000, pp. 5-56 (English).
- ^ R. Bott: The freshwater crabs of Europe, Asia, Australia and their tribal history . In: Treatises of the Senckenbergian natural research society . tape 526 , 1970, pp. 1–338 ( full text (PDF; 14.9 MB)).
- ↑ a b Potamon potamios in the Red List of Endangered Species of the IUCN 2011.1. Posted by: N. Cumberildge, 2008. Retrieved October 1, 2011.
- ↑ EC Maurakis, DV Grimes, L. McGovern, PJ Hogarth: Occurrence of Potamon species (Decapoda, Brachyura) relative to lotic stream factors in Greece. Biologia, Bratislava, 59, pp. 173-179, 2004
- ↑ Darren CJ Yeo & Peter KL Ng: Recognition of two Subfamilies in the Potamidae Ortmann 1896 (Brachyura, Potamidae) with a Note on the Genus Potamon Savigny, 1816. Crustaceana, 76, 10, pp. 1219-1235, 2004, pp. 1232 Online (English; PDF; 242 kB)
- ↑ Gerhard Pretzmann: Two new subspecies of Potamon (Potamon) potamios OLIVIER. Annals of the Natural History Museum in Vienna, ser. B, 87, pp. 255-260, 1986
Web links
- Freshwater crab Potamon potamios - Species description and housing conditions in the invertebrate database (German)