Amynthas mekongianus
Amynthas mekongianus | ||||||||||||
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Systematics | ||||||||||||
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Scientific name | ||||||||||||
Amynthas mekongianus | ||||||||||||
( Cognetti , 1922) |
Amynthas mekongianus is the name of a type of little bristle from the family of Megascolecidae (giantearthworms) in the order of Crassiclitellata (earthworms in the broader sense), whichis widespreadin the Mekong valleyand can reach a length of almost 3 m.
features
Amynthas mekongianus is often 2 m, exceptionally almost 3 m long and on the 5th segment 8 mm to 1 cm, at the tail end 4 mm wide, with adult animals having about 370 or even up to 580 segments. The skin of the giant earthworm is gray in color with a darker back and a dark brown clitellum . Around each segment there are numerous bristles in a ring line , on the 2nd segment 46 with a wide abdominal interruption, on the following up to the 25th segment about 100. The approximately 0.4 mm long and 0.02 mm thick, straight bristles have a nodule shifted towards the tip. The two male genitals of the hermaphrodites sit on the 17th or 18th segment about a sixth of the circumference apart on nodular penises, which are stretched more sideways than in the middle and between which there are 10 bristles. The unpaired female genital opening is located on the abdomen on the 13th or 14th segment. The animal has four pairs of receptacula seminis , which lead outwards on slightly protruding lips between the transition of the segments from the 4th to the 5th to the one from the 7th to the 8th segment. There are no genital papillae as well as copulation bristles.
The foregut has a gummy stomach in the 7th segment, while the midgut begins in the 14th segment and has a pair of simple finger-shaped blind sacs that extend from the 26th to the 21st segment. The intestine does not have any calcification glands.
Distribution, habitat and way of life
Amynthas mekongianus is widespread in the Mekong river basin ( Vietnam , Cambodia , Laos , Thailand ), where it is common in the sandy bank areas and burrows to a depth of 40 cm. Like other crassiclitellates , it is a substrate eater , digesting the organic components of the substrate that is swallowed.
literature
- RJ Blakemore, Cs. Csuzdi, MT Ito, N. Kaneko, MG Paoletti, SE Spiridonov, T. Uchida, BD Van Praagh (2007): Megascolex (Promegascolex) mekongianus Cognetti, 1922 - its extent, ecology and allocation to Amynthas (Clitellata / Oligochaeta: Megascolecidae) . Opusc. Zool. Budapest, 2005 (2007), 36: xx-xx
- RW Sims, EG Easton (1972): A numerical revision of the earthworm genus Pheretima auct. (Megascolecidae: Oligochaeta) with the recognition of new genera and an appendix on the earthworms collected by the Royal Society North Borneo Expedition. Biological Journal of the Linnean Society 4 (3), pp. 169-268, doi: 10.1111 / j.1095-8312.1972.tb00694.x
- Luigi Cognetti de Martiis (1922): Descrizione di tre nuovi Megascolecini. Bolettino dei Musei di Zoologia ed Anatomia comparata della R. Università di Torino. 37 (744), pp. 1-6.