Streptocaulus gracilis Fraser, 1937b, Fraser, 1937

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: 63-64

publication ID

publication LSID

persistent identifier

treatment provided by


scientific name

Streptocaulus gracilis Fraser, 1937b


Streptocaulus gracilis Fraser, 1937b  

Streptocaulus gracilis Fraser, 1937b: 6   , pl. 2, fig. 10.

Holotype. USNM 43293 View Materials : Puerto Rico, off northeast coast, 18°30’20”N, 65°57’00”W, Johnson-Smithsonian Deep- Sea Expedition Sta. 9, 0 1 February 1933, 240–280 fm (439–512 m), R/ V Caroline, one colony, ca. 9 cm high, in fairly good condition, without gonophores, coll GoogleMaps   . Paul Bartsch, labelled “ type ” and “ holotype ”; ethanol.  

Schizoholotype. BCPM 976-00946-001, Puerto Rico, one colony fragment, 1.3 cm high, in good condition, without gonophores; slide (slide is broken lateral to mount).

Type locality. Puerto Rico: off northeast coast, 18°30’20”N, 65°57’00”W, 240–280 fm (439–512 m) (Johnson- Smithsonian Deep-Sea Expedition Sta. 9; Bartsch, 1933). GoogleMaps  

Current status. Valid.

Remarks. The name-bearing type of Streptocaulus gracilis   ( USNM 43293), designated by Fraser (1937b) as a holotype, is listed in the NMNH database as a syntype. Examination of the type material confirms the existence of a single specimen, i.e., the holotype.

The single location record of the species as cited in Fraser’s original account, from the slope north of Puerto Rico (18°33’15”N, 65°56’45”W, 240 fathoms), does not match that of type material (USNM 43293) in the current online database record of the NMNH (syntype, N of St. Thomas, U.S. Virgin Islands, centroid latitude 18.5583, longitude -65, Johnson-Smithsonian Deep-Sea Expedition Sta. 98, 549 m). Neither of these locations appears to be correct. A label in the vial with the holotype specimen indicates that it was collected at Johnson-Smithsonian Deep- Sea Expedition Station 9, not Station 98. According to Bartsch (1933), Stn 9 was occupied at 18°30’20”N, 65°57’00”W, 240–280 fm (439–512 m) on 0 1 February 1933. He reported that at Station 98, sampling gear did not touch bottom and only pelagic animals were collected. A slide of S. gracilis   exists in the RBCM (BCPM 976- 00946-001), but no collection data are provided with it. The species was not listed in Arai (1977). Collection data recorded above correspond with those of Station 9 in Bartsch (1933).

Streptocaulus gracilis   , held to be valid in WoRMS, was described from a single specimen. Its trophosome was said by Fraser (1937b) to be a “Colony 8 cm in height…”, and the record in the NMNH database ( USNM 43293) lists a specimen count of “1.” That specimen is the holotype, and material on a slide at the RBCM ( BCPM 976- 00946-001) represents a fragment of the holotype (i.e., a schizoholotype).

Ramil & Vervoort (1992: 175) suggested that Streptocaulus gracilis   may be referable to family Plumulariidae   rather than Aglaopheniidae   based on trophosomal morphology. If so, it warrants assignment to a genus other than the aglaopheniid taxon Streptocaulus Allman, 1883   . The gonosome of S. gracilis   is unknown.


Smithsonian Institution, National Museum of Natural History


Smithsonian Institution, National Museum of Natural History


Royal British Columbia Museum


British Columbia Provincial Museum














Streptocaulus gracilis Fraser, 1937b

Calder, Dale R. & Choong, Henry H. C. 2018

Streptocaulus gracilis

Fraser, 1937b : 6