Hydroids (Cnidaria, Hydrozoa) from marine fouling assemblages in the Galapagos Islands, Ecuador

An account is given of hydroids collected in 2015 and 2016 from port and harbor fouling communities in the Galapagos Islands. Also included is the hydroid of Ectopleura media, discovered on the wreck of the tanker Jessica near Isla San Cristobal in 2001. Among 20 species reported herein were six anthoathecates and 14 leptothecates. Most common in the samples were the kirchenpaueriid Ventromma halecioides and the halopteridid Halopteris alternata. Eight species (Bougainvillia muscus, Bimeria vestita, Clytia elongata, C. obliqua, C. thornelyi, Obelia oxydentata, Eucheilota sp., and Halecium labiatum) are reported for the first time from the Galapagos archipelago. Three of them (Clytia elongata, C. thornelyi, and Halecium labiatum) are also new to the eastern Pacific. Seven species treated here are considered introduced by shipping to the islands, bringing to eight the number of introduced hydroids. In addition, we treat four species as cryptogenic, bringing to five the total number of the latter in the Galapagos. The binomena Obelia thornelyi Nutting, 1927, Clytia stolonifera Blackburn, 1938, and C. latitheca Millard and Bouillon, 1973 are regarded as synonyms, with the first of these having nomenclatural priority. Meanwhile, the senior synonym O. thornelyi is reassigned to the genus Clytia Lamouroux, 1812 as C. thornelyi. Another species in the samples, Dynamena distans Lamouroux, 1816 (also widely known as Sertularia distans and Tridentata distans), is combined for the first time with the genus Amphisbetia L. Agassiz, 1862, as A. distans.