Symmetroscyphus intermedius ( Congdon, 1907 )

Galea, Horia R., 2008, On a collection of shallow-water hydroids (Cnidaria: Hydrozoa) from Guadeloupe and Les Saintes, French Lesser Antilles, Zootaxa 1878, pp. 1-54 : 37

Symmetroscyphus intermedius ( Congdon, 1907)

(fig. 7C–D)

Thyroscyphus intermedius Congdon, 1907: 482 , figs 33–36.

Symmetroscyphus intermedius — Calder, 1986: 380, figs 1–4.— Calder, 1991d: 77, figs 39–40.

Material examined. Stn. 1: 25.01.2008 —a small, sterile colony, on stolons of Myrionema amboinense Pictet, 1893 ; 18.03.2008 —numerous sterile colonies, on Thalassia testudinum ; 20.03.2008 —one dense, sterile colony, on T. testudinum ; 21.03.2008 —numerous sterile colonies, on T. testudinum ( MHNG INVE 60979); 31.03.2008 —two sterile colonies, on T. testudinum . Stn. 6: 28.03.2008 —several sterile colonies, on T. testudinum . Stn. 7: 25.03.2008 —a small, sterile colony, on stolons of Sertularia marginata Kirchenpauer, 1864 ; 27.03.2008 —a few small, sterile colonies, on various algae.

Type locality. Mangrove Bay, Bermuda.

Remarks. I have little to add to the accurate descriptions given by Calder (1986, 1991d). The category to which the nematocysts of this species belong has not been determined previously ( Calder 1991d). However, the cnidome could be examined in the present material, and the two types of nematocysts are: microbasic euryteles (7.4–7.9) × (1.8–2.1) µm undischarged, (8.6–8.8) × (1.9–2.1) µm discharged; macrobasic amastigophores (25.0–26.3) × (10.0–10.5) µm undischarged, (22.6–23.0) × (8.4–9.1) µm discharged. No gonothecae have been found in our material and they are still to be discovered.

Distribution. Western Atlantic ( Calder 1991d).