Plicatotheca anitae Calder & Vervoort, 1986

Altuna, Álvaro, 2012, New records of bathyal Leptolida (Cnidaria: Hydrozoa: Leptothecata) from the Bay of Biscay and the northwestern Iberian Peninsula (northeastern Atlantic), Zootaxa 3565, pp. 1-17 : 2-4

Plicatotheca anitae Calder & Vervoort, 1986

(fig. 1A–D, table 1)

? Opercularella sp. Nº2: Vervoort, 1966: 108, fig. 8, 12b.

Opercularella sp.: Millard, 1975: 138, fig. 45C, D.

Plicatotheca anitae Calder & Vervoort, 1986: 2021 , fig. 1–4.— Gili et al. 1989: 77, fig. 6B.— Calder, 1991: 4, fig. 1.— Calder, 1993: 67 (table 1).— Vervoort & Watson, 2003: 29, fig. 1H–J.— Bouillon et al. 2006: 297, fig. 139C–D.—Vervoort, 2006: 217, fig. 1f–i, 2 nº4.

Material examined. ECOMARG 2009, Galicia Bank, 23.07.2009, station G6, 42.4217ºN – 11.4488ºW, 761 m, small sterile colonies on bryozoans and worm tubes.

Description. Colonies up to 1.3 cm high, erect, monosiphonic or weakly polysiphonic basally, arising from a thin, creeping hydrorhiza. Hydrocaulus smooth, with perhaps a few corrugations or wrinkles. Internodes long, smooth, with a proximal node, sometimes indistinct. Ramifications irregular, scarce, in one plane, sympodial, with a zig-zag pattern in young branches. Hydrothecae at end of normally long pedicels. Pedicels alternatively left and right, on poorly defined distal apophyses of internodes, with a few basal rings or wrinkles and slightly widening towards distal end. Hydrothecae radially symmetrical, campanulate, with thin and smooth perisarc. Operculum short, formed by 9–10 rounded facets not clearly demarcated from hydrotheca, sometimes distally truncated. Diaphragm basal, very thin. A ring of desmocytes is occasionally present at a short distance over the diaphragm.

Due to unsatisfactory preservation of the material, the tentacles could not be distinguished properly.

Remarks. Colonies of Plicatotheca anitae are similar to those of other species of Opercularella Hincks, 1868 , but the operculum is distinctive. Colonies from Galicia Bank are small and much less than the 10-cm-high specimens cited by Gili et al. (1989), but their morphometrics fully agree with data of other authors ( Table 1 ).

FIGURE. 1. Plicatotheca anitae Calder & Vervoort, 1986 . A) Fragment of colony. B–D) Hydrothecae. Scale bar: A= 200 µm; B–D= 100 µm.

The gonosome of this species is unknown, although Gili et al. (1989) described empty gonothecae. Its systematic position was discussed at length by Calder & Vervoort (1986), and Calder (1991) included it in Phialellidae Russell, 1953 . Bouillon et al. (2006) considered its taxonomic position incertae sedis due to lack of information on its gonophores. Plicatotheca Calder & Vervoort (1986) is a monospecific genus.

Distribution. The present material was dredged at 761 m depth in the Galicia Bank, and the shallowest records are from Bermuda (60–90 m, Calder 1991).

Although seldom recorded, this species has a wide geographic and bathymetric distribution, having been recorded from Bermuda ( Calder & Vervoort 1986; Calder 1991, 1993, 60–90 m depth), Azores (Vervoort 2006, 140 m depth), Guinea Bissau ( Gili et al. 1989, 200– 400 m depth), South Africa ( Vervoort 1966; Millard 1975, 430 m depth) and the Pacific Ocean including New Zealand ( Vervoort & Watson 2003, 370– 1480 m depth). The genus is recorded for the first time as part of the Iberian Peninsula fauna. The nearest record to continental Europe had been that from the Azores.

Tables

TABLE 1. Plicatotheca anitae Calder & Vervoort, 1986. Morphometrics in microns for material from different sources. *) Holotype from Bermuda. **) South Africa. ***) From proximal end to diaphragm.

	Stn G6	Calder & Vervoort (1986); Calder Vervoort (2006) (1991)
Length diaphragm-base operculum	256–286	261–289* 252–280
Diameter at rim	136–176	163–177* 112–168
Diameter at diaphragm	82–116	93–110* 84–95 120–135**
Length of peduncle	353–931***	- -
Diameter of peduncle	64–99	- -
Diameter of internodes	78–117	104–138** - 77–96*