Escharella lopezfei, Souto, Javier, Berning, Björn & Ostrovsky, Andrew N., 2016

Souto, Javier, Berning, Björn & Ostrovsky, Andrew N., 2016, Systematics and diversity of deep-water Cheilostomata (Bryozoa) from Galicia Bank (NE Atlantic), Zootaxa 4067 (4), pp. 401-459 : 432-434

Escharella lopezfei n. sp.

( Figs 76–83 , Table 14 )

Material examined. Holotype: SMF 40.013, locality VH-97-315. Paratypes: SMF 40.014, 40.015, 40.016, 40.017, 40.018, 40.019, 40.020, locality VH-97-315.

Etymology. Honorific for Dr Carlos López-Fé for his contributions to knowledge of bryozoan diversity in the NE Atlantic.

Description. Colony encrusting, unilaminar, forming an irregular patch. Autozooids oval to hexagonal, separated by well-marked grooves; frontal shield strongly, evenly convex, with finely granular surface and single row of tiny, widely spaced marginal pores; additional pores seen in some zooids near orifice. Lateral walls much reduced, with numerous elongated basal pore-chambers, 2–5 combined into elongated areas framed by gymnocystal calcification, 1 distal, 2 distolateral and 2 proximolateral; basal wall only marginally calcified. Orifice suboval, longer than wide; proximal border with rounded triangular lyrula; condyles thick, short and blunt; distolateral margin with 8–9 long, articulated, evenly spaced oral spines, the proximal-most pair level with condyles.

Ovicells hyperstomial, not closed by operculum (acleithral). Ooecium globular, generally wider than long, formed by and continuous with frontal shield of distal autozooid. Ectooecium membranous except for a narrow band of smooth gymnocystal calcification on proximomedian margin. Calcified endooecium thick, imperforate, surface finely granular like zooidal frontal shield. Ovicelled zooids slightly dimorphic, differing from autozooids by presence of gap between distalmost pair of oral spines that laterally border ovicell opening, and by closer spacing of the oral spines.

Kenozooids rare, as large as autozooids, lacking orifice and spines.

SD, standard deviation; N, number of measurements.

Ancestrula oval, smaller than autozooids, gymnocystal walls steeply sloping, well-developed proximally, narrowing distally; opesia confined to distal part of frontal area, transversely oval, proximally constricted by extensive flat cryptocystal shelf with granular surface and narrow smooth distal rim, thin mural rim distinctly raised, surrounded by 12 spines, proximalmost spine directed distally and overarching frontal surface; first daughter autozooid budded distally, second zooid distolaterally.

Remarks. The new species is closely related to Escharella praealta (Calvet, 1907) , originally recorded from more than 700 m depth in the Gulf of Cádiz and later reported from the Canary Islands (as Escharella hexaespinosa Arístegui, 1986 ), from the Strait of Gibraltar at depths as shallow as 30 m (see López de la Cuadra & García- Gómez 1993), and from 2018 m off NW Spain (Reverter-Gil & Fernandez-Pulpeiro 1999b). The anvil-shaped lyrula typical of most Escharella species is reduced to a triangular denticle in both E. praealta and Escharella lopezfei n. sp., which may, however, have the same function as a typical smittinid lyrula (cf. Berning et al. 2014). The new species is distinguished by the lack of an umbo proximal to the orifice and on the proximal ooecium margins, and in having 8–9 oral spines, whereas E. praealta has only six spines. Moreover, the marginal pores in the frontal shield are much less conspicuous in E. lopezfei n. sp. than in the shallow-water specimen figured by López de la Cuadra & García-Gómez (1993, fig. 1H). In contrast, the deep-water populations of E. praealta have equally few pores as in E. lopezfei , which can be seen in the original drawing by Calvet (1907, pl. 28, fig. 6), and also in López de la Cuadra & García-Gómez' (1993, fig. 2) camera-lucida drawing of the holotype. It is thus possible that the shallow- and deep-water populations represent distinct species. The great bathymetric range from 30 m to over 700 m was already highlighted by López de la Cuadra & García-Gómez (1993, p. 465).

Anatomical studies have shown that the ovicells are acleithral in Escharella immersa (Fleming, 1828) (Ostrovsky 2013) . We suggest that the same type of ovicell closure is present in E. lopezfei .

The species was recorded from one station (VH-07-315) at 823 m depth, encrusting corals.

Figures

FIGURES 76 – 83. Escharella lopezfei n. sp.: 76, general view of colony (SMF 40.014); 77, ancestrula and periancestrular zooids (SMF 40.015); 78, 79, zooidal orifices (SMF 40.015); 80, lateral view of autozooid with basal pore-chambers; 81, 82, autozooids with ovicells (holotype); 83, ancestrula.

Tables

TABLE 14. Measurements (in mm) of Escharella lopezfei n. sp.

	Mean	SD	Minimum	Maximum	N
Autozooid length	0.788	0.0533	0.717	0.910	18
Autozooid width	0.610	0.0778	0.485	0.781	18
Orifice length	0.162	0.0107	0.142	0.183	16
Orifice width	0.143	0.0087	0.118	0.153	16
Ooecium length	0.244	0.0025	0.241	0.246	3
Ooecium width	0.374	0.0201	0.360	0.397	3
Ancestrula length	0.396	0.0368	0.370	0.422	2
Ancestrula width	0.348	0.0601	0.305	0.390	2
Ancestrular opesia length	0.132	0.0148	0.121	0.142	2
Ancestrular opesia width	0.183	0.0269	0.164	0.202	2