Glyceridae
| Glyceridae | ||||||||||||
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Glycera alba with everted pharynx, Belgian continental shelf |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Glyceridae | ||||||||||||
| Pit , 1850 |
Glyceridae is the name of a family of long, free-living and burrowing, predatory or detritus-eating polychaeta that can be found in seas around the world.
features
The poly-bristles of the Glyceridae family have several hundred segments and are up to 40 cm long. The conical prostomium of the Glyceridae is ringed and has four small terminal processes. Nuchal organs have so far only been described for the species Glycera convoluta . Characteristic of the Glyceridae is the shape of the long, muscular, evertable pharynx , at the end of which four jaws made of scleroproteins are arranged in a cross and which is covered with different types of papillae. In the genus Glycera, there are poison glands at the base of the jaw, the venom of which is transported through a tube in the jaw and which, through its neurotoxins and proteinases , causes pain that lasts for several days in humans. The peristomium is reduced; there are also no end papillae.
The first segment, like the others, is more or less fused and on which long, jointless palps , lateral and median antennae, 2 pairs of tentacles - cirrus and eyes sit. The eyes, which are very large in some species, can sit directly on the head or in front of protruding ommatophores. A pair is available.
The parapodia are forked in all genus except for Hemipodia , where they are unborked . The neuropodia are larger than the notopodia , and there may be lobes in front of and behind the bristles. Dorsal and ventral cirrus are present. True gills are absent, but dorsal to the parapodia there are gill-like structures without a vascular system through which loop-shaped extensions of the coelom run. The animals also have aciculae. The bristles of the notopodium, if any, are simple, whereas those of the neuropodium are composed. A pair of cirrus is sitting on the pygidium.
In contrast to most of the many bristles, the Glyceridae have neither a heart nor blood vessels. Hemoglobin is dissolved in the coelom fluid, which is kept in motion by the activity of the cilia . There are no partitions between the anterior segments.
Distribution, way of life and example species
The Glyceridae are widespread in seas around the world and live predominantly on sandy or muddy surfaces.
Many Glyceridae - such as the Glycera genus - dig their way through the sediment. These animals are carnivores who grab their prey with their jaws, paralyze it with their poison if necessary, and pull it into its passages. Glycera americana and Glycera alba mainly eat agile prey such as polychaetes and amphipods . The preferred prey of Glycera dibranchiata in Maine is the Polychaet Nereis virens . Some species in other genera feed on detritus and do not dig tunnels.
Development cycle
As far as is known, the Glyceridae are always segregated, and asexual reproduction is unknown. At least nine Glycera species are known to mate in swarms on the surface of the water, release their gametes by tearing open the body wall and then die. Some species show epitocia . The development is a Trochophora larva and three Metatrochophora stadiums before the mature larva drops with a well-developed Prostomium to the ground and at a crawling worm metamorphosed .
Genera
The Glyceridae family is divided into 5 genera :
- Glycera Lamarck, 1818
- Glycerella Arwidsson, 1899
- Hemipodia Kinberg, 1865
- Paranereites Eisenack, 1939 †
- Proboscidea Lesueur in Blainville, 1825
literature
- Stanley J. Edmonds: Fauna of Australia, Volume 4A. Polychaetes & Allies. The Southern Synthesis 4. Commonwealth of Australia, 2000. Class Polychaeta. Pp. 171-174, Family Glyceridae.
Web links
Individual evidence
- ^ Susan B. Rothschild, Beachcomber's Guide to Gulf Coast Marine Life: Texas, Louisiana, Mississippi, Alabama, and Florida. Taylor Trade Publications, 2004, p. 48.
- ↑ Kurt W. Ockelmann, Ola Vahl (1970): On the biology of the polychaete Glycera alba especially its burrowing and feeding. Ophelia 8 (1), pp. 275-294.
- ↑ Colin Little: The Biology of Soft Shores and Estuaries. Oxford University Press, Oxford 2000. p. 87.
- ↑ Glyceridae Grube, 1850. WoRMS , 2018. Retrieved October 29, 2018.