Synthecium gracile Fraser, 1937b

Calder, Dale R. & Choong, Henry H. C., 2018, Names of hydroids (Cnidaria, Hydrozoa) established by Charles McLean Fraser (1872 - 1946), excluding those from Allan Hancock Expeditions, Zootaxa 4487 (1), pp. 1-83 : 49-50

Synthecium gracile Fraser, 1937b

? Sertularella cylindrica var. pusilla Ritchie, 1910: 817 , pl. 77, fig. 9.

Cyclonia gracilis Stechow, 1921b: 230 .

? Hincksella cylindrica Blackburn, 1937: 173 , fig. 2.

Synthecium gracile Fraser, 1937b: 2 , pl. 1, fig. 2 [invalid junior primary homonym of Synthecium gracile Coughtrey, 1875 ]. Hincksella gracilis .— Vervoort & Watson, 2003: 245.

? Hincksella pusilla .— Vervoort & Watson, 2003: 245.

Holotype. USNM 43286 : Puerto Rico, N of Salinas Point, Johnson-Smithsonian Deep-Sea Expedition Sta. 26, 18°30’30”N, 66°23’05”W, 0 7 February 1933, 60– 73 m, R/ V Caroline, one colony on a hydroid stem, ca. 6 mm high, in fair condition, without gonophores, coll. Paul Bartsch, labelled “ type ”; ethanol.

Paratype. BCPM 976-00962-001: Puerto Rico, north coast, Johnson Hydro Sta. 26 (Johnson-Smithsonian Deep-Sea Expedition Sta. 26), 0 7 February 1933, one colony overgrowing another hydroid, in poor condition, without gonothecae, labelled “co-type”; dry sometime in the past, 60% IPA.

Type locality. Puerto Rico: 18°30’30”N, 66°23’05”W, 33–40 fm (60–73 m) ( Bartsch 1933, Sta. 26; Fraser 1937b).

Current status. Invalid.

Remarks. Synthecium gracile was described by Fraser (1937b) from a specimen collected during the Johnson- Smithsonian Deep-Sea Expedition. The single colony at the NMNH (USNM 43286) was designated by him as the holotype, although it is currently listed as a syntype in the NMNH online database. Material in the Fraser Hydroid Collection at the RBCM (BCPM 976-00962-001), from the same location and labelled “co-type”, constitutes a paratype. Another specimen of S. gracile at the RBCM (BCPM 976-00963-001: slide), collected from “Cerros Island” (Cedros Island, Mexico) during the Allan Hancock Pacific Expeditions ( Fraser 1938a), is not type material.

The nomenclature of S. gracile Fraser, 1937b is fraught with homonymy. The name is a junior primary homonym of S. gracile Coughtrey, 1875 (established as S. gracilis , but corrected to S. gracile by Thompson 1879). Homonymy no longer exists between the two names because S. gracile Fraser is now assigned to Hincksella Billard, 1918 , while S. gracile Coughtrey is referred to Amphisbetia L. Agassiz, 1862 . However, the name of Fraser’s species then becomes a junior secondary homonym of Hincksella gracilis ( Stechow, 1921b) (originally Cyclonia gracilis ).

Vervoort & Watson (2003: 245) considered Fraser’s hydroid to be a briefly described and poorly illustrated species of doubtful identity, likely conspecific with Hincksella pusilla ( Ritchie, 1910) from the Mergui Archipelago, Indian Ocean. It is listed by WoRMS as a synonym of H. cylindrica ( Bale, 1888) , in common with Vervoort (1968), Calder (1991), and others. However, Galea & Ferry (2015) presented evidence that H. cylindrica is a species restricted to Australia, and concluded that the species of warm waters in the western Atlantic (including Cyclonia gracilis Stechow, 1921b ) is identical with H. pusilla . With Fraser’s species currently held to be a probable synonym (for a recent synonymy list, see Galea 2010), it seems unnecessary to provide a replacement name for it here.