Moniligastridae

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Moniligastridae
Systematics
Class : Belt worms (Clitellata)
Subclass : Little bristle (Oligochaeta)
Subclass : Diplotesticulata
Superordinate : Metagynophora
Order : Moniligastrida
Family : Moniligastridae
Scientific name of the  order
Moniligastrida
Jamieson , 1988
Scientific name of the  family
Moniligastridae
Claus , 1880

The family Moniligastridae , which at the same time forms the order Moniligastrida , is a taxon of earthworm-like, ground-dwelling little bristles (Oligochaeta) in the ringworm class of belt worms (Clitellata) and comprises around 200 species that are distributed in South Asia and Southeast Asia .

features

In contrast to the Crassiclitellata , to which the earthworms belong, the Moniligastridae have a clitellum , which consists of only one layer of cells, and large, yolk-rich eggs, with which the developing embryos are fully nourished. In this respect, the Moniligastridae resemble the aquatic annelid worms of the families Lumbriculidae and Haplotaxidae . Like all girdle worms, the Moniligastridae are hermaphrodites and have one or two pairs of testicles , suspended in scrotums on the posterior septum of the 10th and / or 11th, more rarely the 11th and / or 12th segment, while vesicle glands are absent. You have a pair of ovaries in the 11th, 12th or 13th segment, always behind the testicles. The spermatic ducts, like the fallopian tubes, only penetrate one segment septum, so that they open outwards in the segment that follows the associated gonads . This is why the male in the Moniligastridae are located in front of the female genital orifices - the opposite of the Crassiclitellata. The ovaries sit in septum chambers. The prostate is capsule-shaped. The receptacula seminis each have a blind sac without sperm. The prostomium is withdrawn. Enterosegmental organs sit dorsally on the intestine.

Outwardly, the Moniligastridae resemble the Crassiclitellata, with which they share the typical original features of the paraphyletic little bristle. They have a fully developed coelom, septate according to segments and acting as a hydroskeleton, as well as a primary closed blood vessel system . They are regularly segmented and have four pairs of bristle sacks on each segment, with which the animals anchor themselves in the ground and which give the necessary support when moving. In contrast to the Crassiclitellata, however, the Moniligastridae do not show any clitellum outside of the mating season, which is why they were referred to by Carl Claus in 1880 as "beltless earth worms".

During copulation, two animals attach to each other with a secretion from the clitellum in the opposite direction and exchange sperm, which are absorbed into the receptacula seminis of the sex partner. Separate management of the egg cells and sperm prevents self-fertilization. A secretion from the clitellum forms an egg cocoon into which the beltworm first releases its own eggs and then the sperm of its sex partner from its receptacula seminis, thus enabling fertilization in the cocoon. Here the embryos develop into finished small worms.

Distribution, habitat and way of life

The Moniligastridae are native to South Asia and Southeast Asia from southern India and Sri Lanka to Manchuria , Korea , Japan , the Philippines , Borneo and Sumatra . Some of the 113 species of the genus Drawida have probably found an even greater distribution through human displacement .

The Moniligastridae live as substrate eater in the soil and humus , where they feed on the microorganisms and the decaying organic material in the swallowed substrate like earthworms.

Genera

The more than 200 species of the Moniligastridae are divided into five genera :

The first species to be described was Moniligaster deshayesi from forest floors near Konni in the western ghats of Kerala in 1872 by Edmond Perrier .

literature