Rhopalonematidae

Crossota sp.

The Rhopalonematidae are cnidarians from the class of hydroids. They are the most species-rich family from the subordination of Trachymedusae.

Features

The manubrium of the Rhopalonematidae is narrow and can be pedunculated or sessile, the mouth has distinct lips. They usually have eight rare but also more narrow Radiärkanäle, Zentripetalkanäle missing. The gonads are either of these and are then spherical or linear or hanging in bags down into the cavity below the screen. The numerous marginal tentacles are evenly distributed around the screen edge or arranged in groups. The most club-shaped sensory organs ( statocysts ) at the edge and are free.

Geographic occurrence and life

The representatives of the family are found worldwide.

System

The family was erected in 1953 by Frederick Stratten Russell, the type genus is Rhopalonema Gegenbaur, 1854. Specified here systematics follows the specifications of the World Hydrozoa database. The family contains 16 genera and 34 to 36 species, making it the largest family of the order of Trachymedusae.

  • Péron & Lesueur Aglaura, 1810
  • Amphogona Browne, 1904
  • Arctapodema Dall, 1907
  • Benthocodon Larson & Harbison, 1990
  • Colobonema Vanhoffen, 1902
  • Crossota Vanhoffen, 1902
  • Pantachogon Maas, 1893
  • Persa McCrady, 1859 ( invalid preoccupied by Bechstein Persa, Persa 1805 and Adams, 1855)
  • Ransonia Kramp, 1947
  • Rhopalonema Gegenbaur, 1854
  • Sminthea Gegenbaur, 1857
  • Stauraglaura Haeckel, 1879
  • Tetrorchis Bigelow, 1909
  • Vampyrocrossota Thuesen, 1993
  • Voragonema Naumov, 1971

Evidence

  • 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
  • Mary Megan Daly, R. Mercer 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, 2007 ISSN 1175-5326 Wellington Abstract - PDF
  • Paul Lassenius Kramp: Synopsis of the Medusae of the World. Journal of the Marine Biological Association of the United Kingdom, 40: 1-469, 1961 Plymouth PDF Online ( p.243 )
Trachylinae
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