Stephanomia Lesueur & Petit, 1807

Pugh, P. R. & Baxter, E. J., 2014, A review of the physonect siphonophore genera Halistemma (Family Agalmatidae) and Stephanomia (Family Stephanomiidae), Zootaxa 3897 (1), pp. 1-111 : 82-83

Genus Stephanomia Lesueur & Petit, 1807

Monotypic for Stephanomia amphytridis Lesueur & Petit, 1807 .

Diagnosis: (see under Stephanomia amphytridis ). Remarks: As noted in the Introduction a variety of physonect siphonophoran species have been described under the generic name Stephanomia , first established by Lesueur & Petit (1807) based on a drawing of part of the siphosome of a, presumably, large physonect that they called S. amphytridis . Further authors have described specimens, again usually of only siphosomal fragments, that they believed belonged to this species but, as has been discussed above, many of these descriptions can actually be attributed to a little known species, Halistemma foliacea , that was briefly described and poorly illustrated by Quoy and Gaimard (1833, 1834). Thus the detailed descriptions of the siphosome Stephanomia amphitridis [sic] given by Huxley (1859) and Bigelow (1911), and another mentioned by Kawamura (1954) have all now been associated with H. foliacea , as has that of S. amphytridis given by Mapstone (2004).

As will be discussed below, although the specimens that we here attribute to Stephanomia amphytridis are indeed large, there appear to have been few previous records, e.g. Totton (1936, 1965) and Daniel (1974, 1985), and only the latter author has given any illustrations, although Totton had started on a manuscript to describe the species. These authors, questionably, attributed the species to the genus Halistemma although, as noted above, Daniel (1985) did comment that her nectophore differed considerably from a typical Halistemma nectophore. None the less, as we shall see, S. amphytridis does have some characters in common with Halistemma species , not least the fact that they both go through a post-larval Nectalia - stage.