Halecium nullinodum Fraser 1935

Halecium nullinodum Fraser, 1935b

Halecium nullinodum Fraser, 1935b: 109, pl. 2, fig. 7.

Type. BCPM 976-00489-001: Japan, Okino-se, shoal outside of Sagami Bay, 22 September 1933, 91 – 110 m, labelled "type"; dry.

Type locality. Japan: Okino-se, outside of Sagami Bay, 100–150 m (Fraser 1935b).

Current status. Valid.

Remarks. Material of this species, from the collection of Emperor Hirohito, was sent to Fraser for identification by Dr. Hirotaro Hattori. While no specimens of Halecium nullinodum are listed in collections at the NMNS, Arai (1977) listed two collections of the species in the Fraser Hydroid Collection at the RBCM (BCPM 976-00489-001; BCPM 976-00489-002). However, one of these (BCPM 976-00489-002), on a slide, bears only a campanulariid colony. Specimens referable to Halecium are lacking on it, and the slide may have been mislabelled originally. The only known type material of Halecium nullinodum is therefore that in a vial at the RBCM (BCPM 976-00489-001), now dry and in very poor condition. It is unclear whether that material comprises one or more than one specimen, and whether it constitutes a holotype by monotypy or syntypes. We are therefore unable to resolve the type status of the collection. In our opinion, a neotype is needed given its unsatisfactory condition.

The trophosome and female gonophores of Halecium nullinodum were described by Fraser (1935b). He did not observe males. Hirohito (1995: 16) regarded H. nullinodum as “a problematic species”, including it with question as a synonym of H. sessile Norman, 1867. Fraser’s species is listed as valid in WoRMS.