Clytia

Calder, Dale R., 2019, On a collection of hydroids (Cnidaria, Hydrozoa) from the southwest coast of Florida, USA, Zootaxa 4689 (1), pp. 1-141 : 56-57

Clytia sp.

Figs. 14 j–l, 16

Material examined. Caloosahatchee River at Fort Myers, 26°38.790’N, 81°52.354’W, on floating dock, less than 1 m, 18 July 2012, 7‰, several colonies, up to 2.1 cm high, with gonophores, coll. D. Calder, ROMIZ B4376.

Remarks. Colonies of this species were found in abundance at a low-salinity site (7‰) in the estuary of the Caloosahatchee River at Fort Myers, Florida. For a species of the genus Clytia Lamouroux, 1812 , the hydroids were notably robust, mostly erect and branched, and large in size (to 2 cm or more). Although colonies with mostly smooth gonothecae were collected, they could not be assigned with confidence to Clytia elsaeoswaldae Stechow, 1914 , or C. gracilis (M. Sars, 1850) , or any other species of the genus Clytia discussed above.

Two types of nematocysts were observed in this hydroid ( Fig. 16). They appear to correspond with A-type b-mastigophores (6.1–6.8 long x 1.6–2.0 μm wide, undischarged, n=10, ROMIZ B4376) and B-type b-mastigo- phores (9.0–10.3 long x 3.0–3.6 μm wide, undischarged, n=10, ROMIZ B4376). Those of the latter type ( Fig. 16b) differ in size and shape from those of hydroids identified here as C. elsaeoswaldae ( Figs. 11c, d), providing additional evidence that the two are specifically distinct.

Certain species of Clytia are known to inhabit brackish waters, but their identities remain obscure. One ecological equivalent is a hydroid identified by me ( Calder 1971) as Clytia hemisphaerica ( Linnaeus, 1767) , found to be abundant in oligohaline waters (0.5–5‰) of both the Pamunkey River and the upper James River, Virginia, USA. I now regard that identification as questionable, even though C. hemisphaerica appears to be a euryhaline species ( Cornelius 1995b: 254). Wedler (1973) identified hydroids from salinities above 20‰ in the brackish Ciénaga Grande of Santa Marta, Colombia, as Laomedea tottoni Leloup, 1935 . That species, taken to be identical with C. linearis ( Thornely, 1900) , is different from material examined here.

I consider this species unidentifiable from presently known characters, and include it here simply as Clytia sp.