Acaulidae

from Wikipedia, the free encyclopedia
Acaulidae
Systematics
Trunk : Cnidarians (Cnidaria)
Class : Hydrozoa (Hydrozoa)
Subclass : Hydroidolina
Order : Anthoathecata
Subordination : Capitata
Family : Acaulidae
Scientific name
Acaulidae
Fraser , 1924

The Acaulidae are a family of hydrozoa (Hydrozoa) from the tribe of the cnidarians (Cnidaria) that live exclusively in the sea . It is a small family of five species in three genera , whose occurrence is restricted to the North Atlantic.

features

The representatives of this group only have a fixed polyp stage , which can also be mobile, and no longer have a free medusa stage . The hydroid polyps are solitary , the body is divided into a basal and a distal part. The basal part is conical to cylindrical and can be surrounded by a gelatinous perisarc that can form filaments for anchoring. A reduced hydroculus (stem or root) or a mucus deposit to anchor to the substrate can also occur. The distal part has one or two tentacle rings. The tentacles are more or less clearly capitat (head-shaped). The upper part of the hydrant has one or two tentacle wreaths around the mouth opening, as well as a few isolated tentacles below these tentacle wreaths. Below the wreaths with capitate tentacles there can be another tentacle wreath, which, however, has filiform tentacles. The gonophores in the lower and middle part of the hydrant are tight sacs of spores. Occasionally, asexual reproduction is observed by dividing the hydrant transversely.

Geographical occurrence and habitat

The few species of the family live in the North Atlantic and its tributaries (Mediterranean, Baltic Sea), z. Sometimes mobile in the system of gaps between coarse shell fragments and in the mud, or attached to grains of sand or shell fragments at depths of about 10 to 300 m.

Systematics

The family name was proposed as Acaulidae by Charles MacLean Fraser in 1924 . The correct name of this family would actually be Acaulididae, because the tribe of Acaulis is Acaulid-. However, all authors following Fraser have always used this misspelling, so that according to the International Rules for Zoological Nomenclature (Art.29.3.1.1) this spelling must be retained. Currently only three genres are included in the family:

swell

literature

  • Jean Bouillon, Cinzia Gravili, Francesc Pagès, Josep-Maria Gili, Fernando Boero: An introduction to Hydrozoa. Publications Scientifiques du Muséum, Paris 2006, ISBN 2-85653-580-1 , ( Mémoires du Muséum national d'Histoire naturelle 194), pp. 1-591.
  • Marymegan Daly, Mercer R. Brugler, Paulyn Cartwright, Allen G. Collin, Michael N. Dawson, Daphne G. Fautin, Scott C. France, Catherine S. McFadden, Dennis M. Opresko, Estefania Rodriguez, Sandra L. Romano, Joel L. Stake: The phylum Cnidaria. A review of phylogenetic patterns and diversity 300 years after Linnaeus. In: Zootaxa 1668, 2007, ISSN  1175-5326 , pp. 127-182, abstract (PDF; 406 kB) .
  • Peter Schuchert: The European athecate hydroids and their medusae (Hydrozoa, Cnidaria): Capitata Part 1. Revue Suisse de Zoologie, 113 (2): 325-410, 2006 PDF

On-line

Individual evidence

  1. ^ Mary Beth Thomas, Nancy C. Edwards, Robert P. Higgins: Cryptohydra thieli n. Gen., N. Sp .: A Meiofaunal Marine Hydroid (Hydroida, Athecata, Capitata). Invertebrate Biology, 114 (2): 107-118, 1995, JSTOR 3226883
  2. ↑ Charles MacLean Fraser: Acaulis primarius Stimpson. Transactions of the Royal Society of Canada, Sec. V, 173: 165-173, 1924.
  3. ^ World Hydrozoa Database

Web links