Egmundella ansini, Gil & Ramil, 2023

Gil, Marta & Ramil, Fran, 2023, The genera Egmundella Stechow, 1921 and Cyclocanna Bigelow, 1918 (Cnidaria, Hydrozoa) in waters of Northwest Africa, Zootaxa 5264 (4), pp. 490-504 : 498-500

Egmundella ansini n. sp.

( Fig. 5 ; Table 4)

Material examined. Western Sahara. MAROC-0611, stn MO239, 23º28′05″– 23º24′32″N, 17º16′24″– 17º16′22″W, 963–969 m, 28-XI-2006: a colony, 2 mm high, with gonothecae, growing on the stem of an unidentified hydrozoan (Holotype, MNCN 2.03 /687) .

MAROC-0611, stn MO275, 25º27′17″– 25º29′34″N, 16º22′06″– 16º21′15″W, 1505–1510 m, 9-XII-2006: a colony, 4 mm high, growing on Streptocaulus chonae , one gonotheca present (Paratype, RMNH.COEL.43831) .

Etymology. The specific name ansini honours our colleague and friend Dr José Ansín-Agís, of the University of Vigo, Spain, in appreciation and recognition of his important contribution to the taxonomy of plumularioid hydroids.

Description. Colonies stolonal, composed of hydrothecae, nematothecae and gonothecae arising from filiform hydroriza. Hydrothecae borne on pedicels of varied lengths, though mostly long ( Fig. 5a, c–g ), smooth, slender, with short basal annulations and occasionally a distally placed, additional annulation; distally widening at junction with the corresponding theca, and there provided with a transverse, thin diaphragm. Hydrotheca deeply campanulate, tapering basally, walls parallel, rim not apparent, aperture closed by a conical operculum composed of 15–18 elongate, triangular flaps, not connected between them, and folded either inwards or outwards. Nematothecae borne irregularly on the hydrorhiza between the hydrothecae; long, slender, without distinct pedicel, aperture distal, circular.

Gonothecae arise perpendicularly to the hydrorhiza, tubular, elongate, tapering basally in small undulations, without distinct pedicel, rim imperceptible, aperture distal, closed by a conical operculum composed of 16 elongate triangular flaps, independent from one another ( Fig. 5a, c ).

Biology. In our material, one colony was growing on the hydroid Streptocaulus chonae Ansín Agís, Ramil & Vervoort, 2001 . Gonothecae have been observed in November and December.

Distribution. Egmundella ansini n. sp. was collected from Western Sahara at depths between 696 and 1510 m.

Remarks. This species is clearly different from both E. grimaldii and C. producta (see below) on the account of the shape of gonothecae and the appearance of its colonies. It is also different from E. modesta , which has colonies and pedicels much smaller than those of E. ansini n. sp.

Our material resembles in morphology to E. superba , E. magellanica Galea et al., 2019 and the material from the “Galathea” Expedition described by Vervoort (1966) as Egmundella sp. Nevertheless, there are considerable differences in size allowing them to be confidently separated specifically.

In E. ansini n. sp. the hydrothecae and pedicels are larger than those of the specimens of E. superba studied herein, and also larger than those described by Calder (1991).

Conversely, E. ansini n. sp. has smaller and narrower gonothecae than those of E. magellanica . Also, its hydrothecae are larger and their pedicels slenderer and lacking the twists of E. magellanica (see table 4).

Finally, Egmundella sp. from the “Galathea” Expedition ( Vervoort 1966) has been only reported from Indonesia, and it seems unlikely that it could be conspecific, given its distribution. In addition, its hydrothecal pedicels have a “few distinct rings” basally ( Vervoort 1966: fig. 9a), while in our material there are only some scarcely-defined annulations ( Fig. 5a ). Moreover, in our material the hydrothecal pedicels are shorter, while the hydrothecae and nematothecae are larger than those of the “Galathea” Expedition ( Vervoort, 1966) (see table 4).

Figures

FIGURE 5. Egmundella ansini n. sp. a–c, stn MO239, a, part of colony with hydrotheca, nematotheca and gonotheca. b, gonotheca, c, hydrotheca atop its pedicel. d–g, stn MO275, d, hydrotheca with incipient gonotheca, e–g, hydrothecae atop their pedicels. Scale bar: a = 0.5 mm; b–g = 1 mm.