Protodrilidae
| Protodrilidae | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Protodrilidae | ||||||||||||
| Hatschek , 1888 |
Protodrilidae is very small, the name of a family in sand gap system of living polychaete (Polychaeta), which are found in oceans around the world and from bacteria feed.
features
The Protodrilidae have a slender, thread-like body that is 2 to 15 mm long and has 21 to 77 segments. The prostomium is fused with several subsequent segments and carries a pair of tentacle-shaped, flexible palps in which two canals with connection run behind the brain, a pair of nuchal organs and, in some species, simple eyes, as well as a pair of organs interpreted as statocysts or light-sensing cells . The pharynx sits on the ventral side with a tongue-like organ and cannot be pushed forward , but Astomus taenioides has no digestive system whatsoever . Outside, individual or adjoining stiff sensory hairs sit in different patterns. A continuous strip of cilia always runs along the ventral side , and tufts or rings of cilia can also sit on the prosomium or trunk. The trunk is segmented, but there are no parapods and bristles. There are usually two sticky rags attached to the pygidium.
habitat
The Protodrilidae live in the sand gap system in comparatively clean, coarse sediments with little detritus in the intertidal zone or below. Most species graze the bacteria that live on the surface of the sank grains.
The animals move with the help of their belly-side eyelash strips and, with the help of sticky substances from glands, are able to adhere to a grain of sand, especially on the two lobes on the pygidium. Astomus taenioides in the coral sands of Moorea ( French Polynesia ), which has only a rudimentary intestine, feeds on dissolved organic substances that are absorbed via enlarged side lobes.
Development cycle
The Protodrilidae are separate sexes. During sexual maturity, the males can be recognized by their lateral organs, which form the spermatophores and sit at the openings in the sperm conductors. The females ingest the spermatophores so that internal fertilization occurs. A female produces 2 to over 150 eggs at a time in a fertile segment. In most species, the fertilized eggs are released by partially tearing the epidermis, but in some species it is released through fallopian tubes, which are protonephridia with a coelomic funnel. The development takes place via a freely swimming trochophora larva.
Genera
The following genera belong to the Protodrilidae family :
- Protodrilus Hatschek, 1881
- Astomus Jouin, 1979 ( synonym Parenterodrilus , only species Astomus taenioides )
- Claudrilus Martínez, Di Domenico, Rouse & Worsaae, 2015
- Lindrilus Martínez, Di Domenico, Rouse & Worsaae, 2015
- Megadrilus Martínez, Di Domenico, Rouse & Worsaae, 2015
- Meiodrilus Martínez, Di Domenico, Rouse & Worsaae, 2015
literature
- Stanley J. Edmonds: Fauna of Australia, Volume 4A. Polychaetes & Allies. The Southern Synthesis 4. Commonwealth of Australia, 2000. Class Polychaeta. Pp. 317f., Family Protodrilidae.
Web links
- Protodrilidae . In: Lexicon of Biology , online edition.
Individual evidence
- ↑ Protodrilidae Hatschek, 1888 WoRMS , 2018. Accessed November 7 2018th