Tricyclusa singularis

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Tricyclusa singularis
Systematics
Subclass : Hydroidolina
Order : Anthoathecata
Subordination : Capitata
Family : Tricyclusidae
Genre : Tricyclusa
Type : Tricyclusa singularis
Scientific name of the  family
Tricyclusidae
Kramp , 1949
Scientific name of the  genus
Tricyclusa
Stechow , 1919
Scientific name of the  species
Tricyclusa singularis
( Schulze , 1876)

Tricyclusa singularis is a species of the hydrozoa (Hydrozoa) from the tribe of the cnidarians (Cnidaria) that lives exclusively in the sea. It is the only species in the genus Tricyclusa Stechow, 1919, which in turn is the only genus in the family Tricyclusidae Kramp, 1949.

features

The hydroid polyps are solitary and are usually attached to the substrate with a small foot disk, usually algae of the seagrass, or rarely live freely in the plankton. The hydrocaulus is thin, about as long as the hydrant, and is covered by a conical, gelatinous perisarc . The surface of this envelope is often wrinkled and detritus particles are often attached. Overall, the hydroid polyp is about 2 mm high, with the hydrant having about 1 mm. The diameter of the foot disk is approximately 0.4 to 0.6 mm.

The hydrant is pear-shaped with an oral wreath of up to six capitate, upturned tentacles, and two widely spaced sets of stiff, solid, aboral, incompletely pearl-shaped tentacles. The middle ring about in the middle of the body usually has six tentacles, which are mostly directed obliquely upwards. They end in a thickening that is covered with nettle cells. One or two further thickenings may be formed in the upper half of the tentacles or may be absent. The two basal, very close together tentacle wreaths consist of a total of 10 to 14, usually 12 tentacles, which are directed alternately upwards and downwards. They too end in a thickening that is covered with nettle cells. One or two other thickenings may or may not be present in the upper half of the tentacles. The following types have been detected in nettle cells : Stenotele , Desmoneme and microbasic Eurytele .

The hydroid polyp buds arise on the lower part below the lowest tentacle ring of the hydrant. The one to six polyp buds form a fully developed hydrant, but with a short stem. These polyps that have just been pinched off can already have attachments of gonophores .

No free-swimming medusas are formed. The female gonophores are fixed spore sacs without a canal system with a single large egg. The diameter is about 0.6 mm. The male gonophores, on the other hand, have four radial channels and one ring channel and can be addressed as medusoids. They are approximately 0.2 mm in diameter.

Geographical distribution and habitat

So far, the species has only been found in the Mediterranean ( Adriatic ) and in the western North Atlantic off northern Brittany and western Ireland. The type locality is in the bay of Muggia ( Adriatic Sea ).

The polyps live attached to various macroalgae such as Cystoseira and seaweeds (such as Zostera ) near the low water line. Occasionally, non-attached polyps can also be found floating in the plankton. In Brittany the polyps were found from May to June, in the Adriatic as early as April. Tricyclusa singularis is a rather rare species; but it can occur in greater numbers where it occurs.

Systematics

Tricyclusa Stechow, 1919 is a replacement name for Tiarella FE Schulze, which was preoccupied by Tiarella Swainson in 1840 and thus invalid. Tricyclusa is the only genus of the Tricyclusidae Kramp, 1949.

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literature

  • Jean Bouillon, Cinzia Gravili, Francesc Pagès, Josep-Maria Gili and Fernando Boero: An introduction to Hydrozoa. Mémoires du Muséum national d 'Histoire naturelle, 194: 1-591, Publications Scientifiques du Muséum, Paris 2006, ISBN 978-2-85653-580-6
  • 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. Zootaxa, 1668: 127-182, Wellington 2007, ISSN  1175-5326 Abstract - PDF
  • Peter Schuchert: The European athecate hydroids and their medusae (Hydrozoa, Cnidaria): Capitata Part 1. Revue Suisse de Zoologie, 113 (2): 325-410, 2006 PDF

Web links

Individual evidence

  1. ↑ Eberhard Stechow: For information on the hydroid fauna of the Mediterranean, America and other areas, together with information on some Kirchenpauer types of plumularids. Zoological yearbooks, Department for Systematics, Geography and Biology of Animals, 42: 1-172, Jena 1920 Online at archive.org
  2. ^ Franz Eilhard Schulze: Tiarella singularis, a new hydroid polyp. Journal of Scientific Zoology, 27: 403-416, Leipzig 1919
  3. ^ Paul Lassenius Kramp: Origin of the hydroid family Corymorphidae. Videnskabelige Meddelelser fra Dansk naturhistorisk Forening i København, 111: 183-215, Copenhagen 1949
  4. ↑ World Hydrozoa Database - Tricyclusidae

Web links