Earleria panicula (G.O. Sars, 1874 )

Gil, Marta, Ramil, Fran & Agís, José Ansín, 2020, Hydroids (Cnidaria, Hydrozoa) from Mauritanian Coral Mounds, Zootaxa 4878 (3), pp. 412-466 : 422

Earleria panicula (G.O. Sars, 1874)

Campanulina panicula: Cornelius, 1995a: 190–192 , fig. 43.

Opercularella panicula: Christiansen, 1972: 291–292 ; Leloup, 1974: 4–6, fig. 3; Ramil & Iglesias, 1988: 79–81, figs. 1–2; Ramil & Vervoort, 1992: 25–27, fig. 3.

Opercularella denticulata: Gili et al. 1989: 75–76 , fig. 6A.

Racemoramus panicula: Calder, 2012: 26 , fig. 24.

Earleria quadrata: Schuchert et al. 2017: 177 , figs. 5–6.

Material examined. MAURIT-0911, stn MUDR02 , 16º08´50”N, 16º57´01”W, 462 m, 5-XII-2009: one colony, badly damaged, no gonothecae .

MAURIT-0911, stn MUDR07 , 18º35´40”N 16º43´12”W, 460 m, 12-XII-2009: one colony, without gonothecae .

Biology. The species can colonize a great variety of substrata, such as hydroids, brachiopods, pennatulids, bivalves, dead corals, polychaete tubes and ascidians ( Cornelius 1995a; Calder 2012). Fertile colonies have been found in April, June, August, November and December ( Ramil & Vervoort 1992; Gili et al. 1989; Cornelius 1995a; Gil & Ramil 2017a).

Gonothecae were not found in our material.

Distribution. Earleria panicula , including its synonyms Campanulina denticulata Clarke, 1907 and Campanulina indivisa Fraser, 1948 , was considered to be widely distributed in the Atlantic, Pacific and Indian Oceans at moderately deep to deep waters ( Ramil & Vervoort 1992). Nevertheless, Calder (2012) considered the material from the Pacific and Indian Oceans to be a different species ( Racemoramus denticulata ), and, in consequence, the current distribution of E. panicula is restricted to the East Atlantic, from Trondheimfjord, Norway ( Calder 2012) to at least Namibia [ Gili et al. 1989, as Opercularella denticulata (Clarke, 1907) ]. In West Africa, it was collected from Morocco [ Ramil & Vervoort 1992, as Opercularella panicula ( Sars, 1874) ] and Mauritania ( Gil & Ramil 2017a). The bathymetric distribution of the species ranges from 30 to 2100 m ( Christiansen 1972; Ramil & Vervoort 1992).

Our material was collected from depths of 460 to 462 m.

Remarks. The material was composed of two colonies with monopodial growth and a cluster of monosiphonic, unsegmented and straight branches with badly damaged terminal hydranths. This morphology was consistent with the typical structure of E. panicula , a species previously recorded in Mauritanian soft bottoms ( Gil & Ramil 2017a, as R. panicula ). Moreover, the Mauritanian material is identical to those reported by Ramil & Vervoort (1992) from the Alboran Sea and Ibero-Moroccan Gulf to off Casablanca.

Recently, Schuchert et al. (2017) used DNA barcoding and found that Earleria quadrata (Hosia & Pagès, 2007) is the medusa of E. panicula . However, differences in the geographical distribution of the medusa, only known in deep waters of Korsfjord ( Norway), and the polyp phase, which is widely distributed in the East Atlantic, led Schuchert et al. (2017) to consider the identity of E. panicula ambiguous, since it could represent a species complex. Nevertheless, samples of Racemoramus panicula from the Alboran Sea and Gulf of Cádiz showed 16S sequences almost identical to that of E. quadrata ( Schuchert et al. 2017) , which seems to supports its co-specificity in at least the Northeast Atlantic. Despite Schuchert et al. (2017) hesitate to synonymise both names, currently they are considered the same species ( Schuchert 2018).