Octochaetidae

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Octochaetidae
Eutrigaster azul

Eutrigaster azul

Systematics
Over trunk : Lophotrochozoa (Lophotrochozoa)
Trunk : Annelids (Annelida)
Class : Belt worms (Clitellata)
Subclass : Little bristle (Oligochaeta)
Order : Earthworms in the broader sense (Crassiclitellata)
Family : Octochaetidae
Scientific name
Octochaetidae
Michaelsen , 1900

Octochaetidae is the name of a family of little bristles in the order of the Crassiclitellata (earthworms in the broader sense) that are common in South America , Central America , Africa and Asia .

features

The Octochaetidae have a cylindrical body on which dorsal pores are usually present. There are 4 pairs of bristles on each segment .

The esophagus usually forms 1 to 3 gizzards , while there are no gizzards in the midgut. The intestinal canal also has calcified glands, while only a few species (in the genus Millsonia ) have cecumus . The closed blood vessel system of the Octochaetidae generally has a similarly constructed supra-oesophageal vessel in the front part of the body next to the back vessel. The nephridia are only partially developed (meronephridial).

The clitellum the hybrid is ring-shaped or saddle-shaped and generally takes between 12 and 18. Segment segments 6 to 7 and is rarely longer, so in the genus Agastrodrilus about 30 segments. A pubertal tubercle is absent, but genital papillae or porophores are generally present. The pair of male genital orifices is usually located in the 18th segment on the posterior edge or within the clitellum. The tubular prostates have a central canal and lead in two pairs of exits in the 17th and 19th segments or in one pair in the 17th, 18th and 19th segments, then in some cases together with the male exits to the outside. In the genus Hoplochaetella , 2 pairs of male pores and 2 pairs of prostate exits in the 18th and 19th segments lead together to the outside. There are 9 pairs of male sexual outlets in the genus Agastrodrilus . The receptacula seminis and their exits sit in front of the testicles.

Distribution, habitat and way of life

The Octochaetidae are distributed in temperate zones of Australasia and in the tropics of South America , Central America and Africa , in Asia from India to Myanmar . Some species of the genus Dichogaster have also been transported to other regions by humans. The Octochaetidae, like other Crassiclitellates, are soil-dwellers and substrate- eaters , which digest the organic components of the ingested substrate.

Genera

The family Octochaetidae has around 30 genera :

literature

  • Wilhelm Michaelsen: Oligochaeta: Vermes. R. Friedländer and Son, Berlin 1900. Octochaetidae , p. 446.
  • Reginald William Sims (1981): A classification and the distribution of earthworms, suborder Lumbricina (Haplotaxida: Oligochaeta). Bulletin of the British Museum (Natural History), Zoology Series 39 (2), pp. 103–124, here p. 113.