Suborder Calycophorae Leuckart, 1854

Diagnosis

Siphonophorae without pneumatophore, highly polymorphic, with a nectosome typically formed by one or two nectophores. A single bract is developed on each cormidial unit, with the exception of the family Hippopodiidae whre bracts are absent. Generally the cormidial units are detached successively from the stem and become eudoxid, or sexual stage.

Higher classification

Metazoa, Cnidaria, Medusozoa, Hydrozoa, Leptolinae,  Siphonophorae

References

Kirkpatrick, P. A., & Pugh, P. R. 1984. Siphonophores and velellids. Synopses of the British Fauna (New Series) 29: 1-154.

Pages, F., & Gili, J.-M. 1992. Siphonophores (Cnidaria, Hydrozoa) of the Benguela Current (southeastern Atlantic). Scientia Marina  56: 65-112.

Totton, A. K. 1965. A synopsis of Siphonophora - British Museum (natural History), London: 230 pp.

Classification

Family Abylidae 

Calycophorae which develop a temporary larval bract before the larval nectophore, the latter is retained in the polygastric stage as the anterior nectophore. All but one species develop a second (definitive) nectophore, the posterior one, which is usually considerably larger than the anterior one and does not posess a somatocyst. The nectophores are ridgy and angular, the posterior one usually bearing serrated ridges and teeth. The hydroecium of the anterior nectophore is an enclosed tube opening basally.

Family Clausophyidae

Calycophorae in which both anterior and posterior nectophores possess a somatocyst. The nectophores are stream-lined, although the hydroecium is more prominent than in the diphyids. The phyllocyst of the eudoxid bracts characteristically bears two fine basal branches extending down into the neck shield.

Family Diphyidae

Calycophorae with usually two dissimilar, streamlined definitive nectophores arranged serially; the anterior nectophore posses a somatocyst, the posterior not, somatocyst often with oil droplets for buoyancy control; the hydroecium generally reduced in anterior nectophore; a nectosac occupies most of the nectophore and, with the overall streamlining, enables the aniumals to be fast and active swimmers.

Family Hippopodiidae 

Calycophorae with biserial arrangement of up to sixteen or more flattened definitive nectophores in varying stages of development, the youngest being apical, fitting tightly together around a thin stem which can be retracted between them; without bracts, gonophores arise directly from siphosomal stem, being released at maturation.

Family Prayidae

Calycophorae with relatively large and usually rounded nectophores, containing large quantities of mesogloea; the larval nectophore sometimes retained during polygastric stage or may be replaced by one to four definitive nectophores, whose somatocysts are often complexly branched; the eudoxid bracts are rounded and unridged.

Family Sphaeronectidae

Calycophorae with a single spherical nectophore of larval origin.