P.P Shirshov Institute of Oceanology
Ctenophora, also known as comb jellies, is a phylum of marine, predominantly planktonic invertebrates that comprise ~190 described species. Ctenophores can be found in most marine habitats and their size can range from a few millimetres to 1,5 metres long. Ctenophores have bi-radial symmetry with an underlying bilateral body plan that is visible in the arrangement of tentacles, form of the mouth and structure of gastrovascular system. The sense organ is arranged at aboral pole of the body just opposite two anal pores. The most distinctive feature of ctenophores is presence of the "combs", groups of cilia, generally arranged in eight longitudinal rows, which they use for locomotion. Most ctenophores have two tentacles that may be well-developed or visible only during part of their life cycle. Tentacles are developed in the plane that is perpendicular to the plane of the stomach. In some species tentacles can reach considerable length. Deep-sea ctenophores are poorly known, with many species left to discover, as the preservation of these delicate animals is extremely tricky and hardly can be achieved.
Taxonomic characters used in identification
Form of the body, comb rows (length, comb morphology), tentacles (length, morphology, side branches), gastrovascular system, mouth lobes
Identification of the images and taxonomic resolution
Some iconic species can be distinguished from underwater photographs but deep-sea ctenophores are poorly known and many deep-water species are still undescribed. For characteristics of the morphotypes encountered in CCFZ we used form of the body and presence/absence of tentacles.
List of morphotypes
Harbison, G.R., G.I. Matsumoto & B.H. Robison, 2001. Lampocteis cruentiventer gen. nov., sp. nov.: a new mesopelagic lobate ctenophore, representing the type of a new family (class Tentaculata, order Lobata, family Lampoctenidae, fam.nov.). Bull. Mar. Sci., 68(2): 299-311
Lindsay D.J. & Hunt J.C., 2005. Biodiversity in midwater cnidarians and ctenophores: submersible- based results from deep-water bays in the Japan Sea and North-western Pacific.― J. Mar. Biol. Assoc. UK 85: 503–517
Lindsay, D.J. & Miyake, H. (2007) A novel benthopelagic ctenophore from 7217 m depth in the Ryukyu Trench, Japan, with notes on the taxonomy of deep sea cydippids. Plankton and Benthos Research 2, 98–102
Madin, L.P. & G.R. Harbison, 1978. Bathocyroe fosteri gen. nov., sp. nov.: a mesopelagic ctenophore ob served and collected from a submersible. J. Mar. Biol. Assoc. UK 58: 559-564