Stenohelia Kent, 1870

Cairns, Stephen D. & Zibrowius, Helmut, 2013, Stylasteridae (Cnidaria, Hydrozoa, Filifera) from South Africa, Zootaxa 3691 (1), pp. 1-57 : 36

Genus Stenohelia Kent, 1870

Stenohelia Kent, 1871: 121 .—Boschma, 1956a: F100.—Cairns, 1983b: 486–487; 1986a, 94; 1986b: 19; 1991: 70; 1992: 540– 541 (key).

Type Species. Allopora maderensis Johnson, 1862 , by subsequent designation (Broch 1936).

Diagnosis. Colonies uniplanar and usually quite delicate, often living in association with commensal polynoid polychaetes. Coenosteal texture usually linear-imbricate, reticulate-imbricate, or finely imbricate; usually white or yellow in colour. Gastro- and dactylopores arranged in cyclosystems, which occur exclusively on anterior branch faces. Gastropore tubes usually elongate and curved 90°, such that the gastrostyle tip cannot be seen in surface view. Gastrostyle encircled by a ring palisade or a sphincter. Dactylostyles usually well developed, although some species have dactyloglossae instead. Ampullae superficial, often clustered, with discrete efferent pores.

Discussion. Ten valid Recent species are recognized in the genus and another putative fossil species from the Eocene of Tonga (see Cairns 1991; Cairns et al. 1999; Appeltans et al. 2012). Representatives of all but two of these species (the Japanese species S. yabei and S. echinata ) were examined for comparisons. The two new species described below bring the total to 12 Recent species in this genus, including the second and third southern hemisphere species.

Holocene Distribution. Atlantic, Pacific and Indian Oceans, 91–2021 m.