Family PLEUROBRACHIIDAE Chun, 1880

Museums

Regional Maps

Introduction

The family Pleurobrachiidae was proposed by Chun (1880). It comprised the taxa Hormiphora and Pleurobrachia (grouped as Pleurobrachiadae ovatae), and Lampetia and Euplokamis (grouped as Pleurobrachiadae cylindricae). Lampetia was moved to its own family, the Lampeidae, by Stechow (1921), and Euplokamis was placed in its own family, the Euplokamididae, by Mills (1987). Today, the family comprises two genera, Pleurobrachia and Hormiphora. One described species, Pleurobrachia pileus, is reported from Australian waters. However, an unidentified species of Pleurobrachia has been reported from Queensland by Hamond (1971) and a unidentified species of Hormiphora has been reported by Edgar (1997, 2000).

Species of Pleurobrachia are found in polar to tropical waters usually close to shore, and species of Hormiphora are found in temperate to tropical oceanic waters. Prey items, including small crustaceans and larval fish, are captured by the tentacles and conveyed to the mouth by means of a reversal of the ciliary beating by adjasubtentacular comb rows, causing the animal to twirl and tumble until the prey is conveyed across the lips.

For additional information see Chun (1880), Stechow (1921), Harbison & Madin (1982), Harbison (1985) and Mills (1987). Introduction adapted from Harbison & Madin (1982).

Diagnosis

The body is slightly compressed in the stomodaeal plane; it is spherical, oval, or cylindrical in general appearance. The tentacle sheaths open aborally to the infundibulum, near the apical sense organ. The tentacles have filiform side branches (Pleurobrachia) or heterogeneous side branches (Hormiphora). Tentacle sacs lie close to the stomodaeum (Hormiphora) or at some distance from it (Pleurobrachia). The meridional canals are no longer than the comb rows, which are relatively short (Pleurobrachia, Hormiphora) or almost as long as the body (Pleurobrachia). Gonads are present on all meridional canals. Newly hatched juveniles closely resemble adults. Adults are small (no more than 1-2 cm in height) and usually transparent, although some are pigmented.

Diagnosis References

Harbison, G.R. & Madin, L.P. 1982. Ctenophora. 707-715, pls 68-69 in Parker, S.P. (ed.). Taxonomy and Classification of Living Organisms. New York : McGraw-Hill Vol. 1. [708]

General References

Chun, C. 1880. Die ctenophoren des Golfes von Neapel und der angrenzenden Meeres-abschnitte. Fauna und Flora des Golfes von Neapel 1: 1-313, 16 pls

Edgar, G.J. 1997. Australian Marine Life, the plants and animals of temperate waters. Kew, Victoria, Australia : Reed Books 544 pp.

Edgar, G.J. 2000. Australian Marine Life: the plants and animals of temperate waters. Sydney : Reed New Holland Revised Edn, 544 pp.

Harbison, G.R. 1985. On the classification and evolution of the Ctenophora. pp. 78-100 in Morris, S.C., George, J.D., Gibson, R. & Platt, H.M. (eds). The origins and relationships of lower invertebrates. Oxford : Oxford University Press.

Harbison, G.R. & Madin, L.P. 1982. Ctenophora. 707-715, pls 68-69 in Parker, S.P. (ed.). Taxonomy and Classification of Living Organisms. New York : McGraw-Hill Vol. 1.

Mills, C.E. 1987. Revised classification of the genus Euplokamis Chun, 1880 (Ctenophora: Cydippida: Euplokamidae n. fam.) with a description of the new species Euplokamis dunlapae. Canadian Journal of Zoology 65: 2661-2668

Stechow, E. 1921. Neue Genera und Species von Hydrozoen und anderen Evertebraten. Archiv für Naturgeschichte A 87: 248-265

History of changes