Scalibregmatidae

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Scalibregmatidae
Scalibregma hanseni

Scalibregma hanseni

Systematics
Empire : Animals (Animalia)
Over trunk : Lophotrochozoa (Lophotrochozoa)
Trunk : Annelids (Annelida)
Class : Polychaete (Polychaeta)
Order : Scolecida
Family : Scalibregmatidae
Scientific name
Scalibregmatidae
Malmgren , 1867

Scalibregmatidae is the name of a family of Vielborstern (Polychaeta), which are found in oceans worldwide in soft sediments as detritus from the coast to the deep sea.

features

The Scalibregmatidae have a maggot-like or moderately elongated body with a wrinkled and curled epidermis. The head has horn-like appendages, but it has no real body appendages such as antennae or palps. The prostomium is cut off, T-shaped or V-shaped. The peristomium forms a ring that is partially divided into two on the dorsal and lateral surfaces. The nuchal organs consist of short ciliate grooves.

The longitudinal muscles are arranged in bundles. The segmentation is clear, and the first segment is similar to the second and, like this, bears small, fully developed parapodies . Both branches of the parapodia are short, conical or cut off, and both dorsal and ventral cirrus are absent. In most species, the branched gills are in tufts and are connected to the parapodia. Numerous papillae may stand or be absent on the pygidium. The animals have lateral organs, but no dorsal cirrus organs have been observed. The parapodia have smooth or ornate capillary-shaped and forked bristles , and the first bristle-bearing segments of some species are also studded with spines, while aciculae are absent.

The evertable pharynx is a simple, axially located sac designed as a proboscis (trunk). The animals do not have a throat membrane. The intestinal canal forms a simple tube. The closed blood vessel system of the Scalibregmatidae does not have a central heart. The nephridia are designed as mixonephridia. The location where the gametes are released is not known.

habitat

The Scalibregmatidae live in mud and other soft sediments from the intertidal zone to sea depths below 1000 m. The animals inhabit tunnels they dug themselves in the sediment, which are often 30 to 60 cm below the surface. Species of the genus Hyboscolex live in muddy rock crevices and also inhabit old burrows of other animal species. Species of the genus Parasclerocheilus and, similarly, Scalibregma live under loose stones in a muddy environment. Apparently there are no species in this family that build their own residential tubes.

Development cycle

Little is known about the reproductive biology of the Scalibregmatidae. Most or all of the species are probably sexually separated with external pollination, with at least some species forming epitoks . The embryos develop into larvae, which only after a free swimming phase metamorphose into crawling worms . For Scalibregma inflatum on the Scottish coast, which reaches sexual maturity in the first year of life, a life span of two years is estimated.

nutrition

The diet has been studied in two species of the Scalibregmatidae: have a sac-like eversible pharynx. Scalibregma inflatum and Polyphysia crassa . Both species actively dig their way through the sediment, which they swallow as substrate eater with the help of their sac-like, evertable pharynx . They digest the detritus contained therein and excrete the minor components unchanged. Scalibregma inflatum may also pick up detritus from the surface of the soil, while Polyphysia crassa is likely to eat chamberlings as well . For this purpose, the pharynx is everted and everted in the coelom by hydraulic pressure.

Genera

The more than 40 species of the Scalibregmatidae family belong to 16 genera :

literature

  • Stanley J. Edmonds: Fauna of Australia, Volume 4A. Polychaetes & Allies. The Southern Synthesis 4. Commonwealth of Australia, 2000. Class Polychaeta. Pp. 113-115, Family Scalibregmatidae.

Web links

Commons : Scalibregmatidae  - collection of images, videos and audio files

Individual evidence

  1. ↑ Scalibregmatidae Malmgren, 1867. WoRMS , 2018. Retrieved November 19, 2018.