Coryne sp. 1

Calder, Dale R., 2010, Some anthoathecate hydroids and limnopolyps (Cnidaria, Hydrozoa) from the Hawaiian archipelago 2590, Zootaxa 2590 (1), pp. 1-91 : 52-53

Coryne sp. 1

Figs. 34, 35

Syncoryne mirabilis .— Chu & Cutress, 1955: 403, fig. 3 [not Sarsia mirabilis L. Agassiz, 1849 (= Sarsia tubulosa (M. Sars, 1835) ].

Material examined. Oahu: Hawaii Kai , on pilings of bridge over Highway 72, 21º17’06.60”N, 157º43’07.21”W, 0.1 m, 27.vii.2009, on algae, two colonies, to 2 mm high, without gonophores, coll. D.R. Calder, ROMIZ B3828 .

Description. Hydroid colonies mostly stolonal, up to 2 mm high, arising from a creeping hydrorhiza. Hydrocaulus monosiphonic, short, unbranched or with an irregular branch, bearing a terminal hydranth. Perisarc transparent, with that on hydrorhiza mostly smooth and of moderate thickness, that on hydrocauli thinner, smooth to wrinkled almost throughout, not regularly annulated, terminating at base of hydranth below tentacles. Hydranths when extended elongate, cylindrical to clavate, to about 1 mm high and 0.15 mm wide; when contracted oval, much shorter and wider; tentacles all capitate, about 20 in number, with four in an oral whorl, the remainder in about four irregular whorls over remainder of hydranth body, each whorl usually with four tentacles, those of one whorl alternating with tentacles in adjacent whorls; terminal knobs about 60 µm in diameter; hypostome prominent, dome-shaped to cap-shaped.

Gonophores not seen.

Remarks. Hydroid colonies identified here as Coryne sp. 1 , from a small inlet into the western harbor at Hawaii Kai, on Oahu, are believed to be conspecific with specimens identified as Syncoryne mirabilis (L. Agassiz, 1849) from the mouth of the Wailoa River, Hilo Harbor, Island of Hawaii, by Chu & Cutress (1955). From their illustration and brief description, the hydroids from Hilo Harbor are also believed to be a species of Coryne Gaertner, 1774 . In morphology they resemble colonies examined here, and they were collected from a similar environment. Hydranths in material from Hilo Harbor arose from creeping stolons, and bore 15 or more scattered capitate tentacles. Medusae, formed on a part of the body column where the proximal-most tentacles would have occurred, were reported to be mature before liberation from the hydroid. The species was thought by Chu & Cutress to be responsible for cases of dermatitis in workers constructing a pier in the area. Of the described species of Corynidae ( Schuchert 2001b) , none has the characters shared by hydroids from Hawaii Kai and Hilo Harbor. This hydroid may be a new species, but more information on the life cycle is needed before describing it as such.

Cooke (1977) provided a brief description and sketch of a corynid hydroid found in alpheid crevices on the coral Porites lobata in Hawaii, and suggested that it might be the same as that identified as Syncoryne mirabilis by Chu & Cutress (1955). Gonophores were not observed on his hydroids, and no material of the species exists in collections at the Bishop Museum. Cooke’s specimens had fewer tentacles (no more than 12) than those of Chu & Cutress (15 or more) and of the hydroid colonies described above from Hawaii Kai. Given apparent differences in morphology and habitat, Cooke’s corynid is treated as a different species ( Coryne sp. 2 ) here.

Coryne sp. 1 was found in very shallow waters on algae attached to the piling of a bridge over a small inlet leading into the western harbor of Hawaii Kai. Tidal flow of water moves through the inlet and ample hard substrate is present (rocks, concrete pilings, mollusc shells, algae, bryozoans, etc.), making it a favourable location for hydroids. The species is small and inconspicuous.

Reported distribution. Hawaii. Oahu: Hawaii Kai (this study).