Cordylophora caspia ( Pallas, 1771 )

Calder, Dale R., 2019, On a collection of hydroids (Cnidaria, Hydrozoa) from the southwest coast of Florida, USA, Zootaxa 4689 (1), pp. 1-141 : 16

Cordylophora caspia ( Pallas, 1771)

Fig. 1f

Tubularia caspia Pallas, 1771: 479 .

Cordylophora lacustris Wurtz & Roback, 1955: 178 .— Mason et al., 1994: 152.

Type locality. “In Mari Caspio…” ( Pallas 1771: 479).

Material examined. Caloosahatchee River at Fort Myers, on floating dock, <1 m, 22° C, 0.17‰, 02 November 2017, one colony, 0.9 cm high, without gonophores, coll. D. Calder, ROMIZ B4328.— Caloosahatchee River at Fort Myers, on floating dock, <1 m, 20° C, 6‰, 06 February 2018, several colonies, up to 9 mm high, with gonophores, coll. D. Calder, ROMIZ B4329 .

Remarks. Cordylophora caspia is reported here for the first time from the southwest coast of Florida. The species has been recorded previously from the Escambia River ( Wurtz & Roback 1955) and from the Suwannee River system ( Mason et al. 1994), both in northern parts of the state. Somewhat inland from the Gulf coast of Florida, colonies of C. caspia were found by Streever (1992) in a flooded cave system at Little River Spring, Suwannee County.

When first collected during this study, from the Caloosahatchee River estuary at Fort Myers, Florida (ROMIZ B4328), specimens of C. caspia were dormant. Within 24 hours, however, a hydranth appeared on one of the hydrocauli held in a fingerbowl of brackish water. Colonies are believed to have been inactive at the time due to environmental stresses introduced after passage of Hurricane Irma through south Florida on 11 September 2017. As a result of the storm, heavy freshwater discharge into the river from nearby Lake Okeechobee had been authorized by the United States Army Corps of Engineers to prevent catastrophic flooding in the vicinity. Normal salinities at the location are in the oligohaline (0.5–5‰) to mesohaline (5–18‰) range, but river waters at Fort Myers were still fresh (0.17‰) when the dormant stems and stolons were collected. At the same site a few months later, active colonies with gonophores (ROMIZ B4329) were collected (06 February 2018) in salinities that were somewhat higher (6‰). With still higher salinities (15‰) the following month (29 March 2018), however, neither active nor inactive colonies were found.

Remarks on this well-known invasive hydroid, and on the likely existence of cryptic species under the name C. caspia , have been given previously ( Folino 2000; Schuchert 2004; Folino-Rorem et al. 2009; Calder 2010).

Reported distribution. Gulf coast of Florida. Escambia River, 1.2 miles (1.9 km) from mouth ( Wurtz & Roback 1955: 178, as Cordylophora lacustris ).—Suwannee River and Estuary ( Mason et al. 1994: 152, as Cordylophora lacustris ).

Elsewhere in western North Atlantic. Atlantic and Gulf coasts of North America: widespread in areas of low salinity (see Folino 2000; Folino-Rorem et al. 2009; National Exotic Marine and Estuarine Species Information System: http://invasions.si.edu/nemesis/CH-INV.jsp?Species_name= Cordylophora +caspia).

Figures

FIGURE 1. a, Pennaria disticha: part of branch, with pedicel and hydranth, Fort Myers Beach, ROMIZ B4347. Scale equals 0.5 mm. b, Corydendrium parasiticum: part of colony with a reduced hydranth, Southwest Florida Shelf, ROMIZ B449. Scale equals 0.5 mm. c, Rhizogeton sterreri: hydranth and stolon, Fort Myers Beach, ROMIZ B4326. Scale equals 0.2 mm. d, Rhizogeton sterreri: male gonophore and stolon, Fort Myers Beach, ROMIZ B4326. Scale equals 0.2 mm. e, Turritopsis nutricula: colony with two hydranths, Fort Myers Beach, ROMIZ B4327. Scale equals 0.2 mm. f, Cordylophora caspia: part of colony with hydranth and female gonophore, Caloosahatchee River at Fort Myers, ROMIZ B4329. Scale equals 0.2 mm.