Phyllodocidae

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Phyllodocidae
Phyllodoce lineata

Phyllodoce lineata

Systematics
Empire : Animals (Animalia)
Trunk : Annelids (Annelida)
Class : Polychaete (Polychaeta)
Subclass : Aciculata
Order : Phyllodocida
Family : Phyllodocidae
Scientific name
Phyllodocidae
Örsted , 1843

Phyllodocidae is the name of a family of medium to large, wild, grave forming in the seabed, mostly predatory or as scavengers living polychaete , which are found in oceans worldwide (Polychaeta).

features

The often brightly colored multi-bristles of the family Phyllodocidae are usually not more than 10 cm long with a number of 50 to 100 segments , but in the genus Phyllodoce it can be up to 30 cm with around 600 segments.

Characteristic for the family are the muscular, evertable pharynx , mostly covered with papillae, and the leaf-like dorsal cirrus . The prostomium carries a pair of anterior antennae and a pair of simple palps that resemble the paired antennae. A middle antenna or neck papilla and a pair of eyes can also be present, while a pair of nuchal organs is always to be found. End papillae are attached to the mouth, but there are no jaws. The first segment usually has a pair of tentacles , two pairs in the genus Eteone . The first two or three segments can be partially fused and carry a total of two to four pairs of tentacle cirrus. Both the dorsal and the ventral cirrus are leaf-like, the dorsal ones being usually much larger than the ventral ones. The parapodia are unbranched or branched with poorly developed notopodia . While there are no bristles on the first segment, on the following segments there are composite capillary-like and rarely simple bristles on the neuropodia, and simple capillary-like bristles on the notopodia, if any. A pair of cirrus is sitting on the pygidium.

The animals have no gills, but the leaf-like dorsal cirrus may be used for breathing. The weakly developed vascular system has no central heart, and consists of a back vessel in which the colorless blood flows generally from front to back, and a belly vessel with the former by not completely from the coelom is connected Lateralgefäße separated.

distribution and habitat

The Phyllodocidae are widespread in seas around the world, where they especially inhabit sandy and muddy seabeds or estuaries .

Development cycle

The Phyllodocidae are separate sexes, and many species form large schools when mating. Only a few species undergo significant physical changes, such as Eulalia bilineata , Mystides limbata and two species of Protomystides , in which animals ready to mate have specialized capillary-like bristles. The swarm -forming species Eumida sanguinea , Pirakia punctifera , Phyllodoce mucosa and Phyllodoce lamelligera as well as the non- swarm -forming species Eulalia viridis remain unchanged during mating . As a rule, the animals mate when they are at least two years old and do so several times in their life. The egg cells are fertilized in the open sea.

Notophyllum foliosum is the only known species of the family to carry its eggs in yellow gelatinous bands on its posterior notopodia. Eulalia viridis produces gelatinous, green egg clutches that itattachesto brown algae . The gelatinous clutches of Phyllodoce mucosa can contain over 10,000 eggs. The larval development is known in Eteone dilatae , Eteone picta , Eteone longa , Eulalia viridis , Phyllodoce maculata and Phyllodoce mucosa . The larvae develop through two free-floating Trochophora - and two Metatrochophora stadiums before leaving after 8 to 65 days at a number of 5 to 9 segments sink down and crawling worms metamorphose . The trochophora is strongly positive phototactic and swims by the blink of an eye of the prototroch, whose activity decreases with increasing larval age.

nutrition

The diet has only been studied in a few species of the Phyllodocidae. Both Phyllodoce mucosa and Eulalia viridis feed on the meat of dead or dying animals as scavengers . Other species feed on live prey - mostly other polychaetes - that are seized with the evertable pharynx. Eteone species of the intertidal zone follow the traces of slime left by prey. Eteone heteropoda eats both poly-bristles such as Nereis succinea and sediment containing detritus , while Eteone longa eats the spyids Spio filicornis and Scolelepis squamata .

Genera

The family Phyllodocidae is divided into 19 genera :

Eteoninae Bergström, 1914
Notophyllinae Pleijel, 1991
Phyllodocinae Örsted, 1843

literature

Web links

Commons : Phyllodocidae  - Collection of images, videos, and audio files

Individual evidence

  1. ↑ Phyllodocidae Örsted, 1843. WoRMS , 2018. Retrieved October 25, 2018.