Bathycyclopora suroiti, Berning & Harmelin & Bader & Cibio, 2017

Berning, Björn, Harmelin, Jean-Georges & Bader, Beate, 2017, New Cheilostomata (Bryozoa) from NE Atlantic seamounts, islands, and the continental slope: evidence for deep-sea endemism, European Journal of Taxonomy 347, pp. 1-51 : 34-37

Bathycyclopora suroiti gen. et sp. nov.

urn:lsid:zoobank.org:act:84D62316-64CF-4429-9610-D8A26DDA83D9

Fig. 12 A–G, Table 12

Diagnosis

Bathycyclopora suroiti gen. et sp. nov. differs from the type species B. vibraculata gen. et comb. nov. in having a frontal shield with slightly more pronounced ridges, seven or eight oral spines in non-maternal zooids, distinctly smaller and blunt condyles, a narrower shelf at the distal orifice margin, slightly longer and less spatulate interzooidal avicularia, a distinctly broader ectooecium around the ooecial margin, ooecia that are only slightly wider than long, and an ancestrula with 13 instead of 11 spines.

Etymology

The species is named after the French research vessel ‘Le Suroît’, and the cruise ‘Suroît Seamount 2’, which aimed at sampling the central North Atlantic seamounts.

Material examined

Holotype

ATLANTIS SMT: 1 ovicellate colony on stylasterid skeleton, Stn 7 ( MNHN-IB-2014-73 ).

Paratypes

ATLANTIS SMT: 1 ovicellate colony on rock, Stn 6 (MNHN-IB- 2014-74); 2 colonies on stylasterid skeleton, Stn 7 (MNHN-IB- 2014-75); 1 coated colony on stylasterid skeleton, Stn 7 (MNHN- IB- 2014-76); 1 coated colony on stylasterid skeleton, Stn 7 (MNHN-IB- 2014-77); 1 colony on stylasterid skeleton, Stn 7 ( OLL 2016/126); 1 colony on stylasterid skeleton, Stn 7 ( OLL 2016/148); 1 colony on foraminiferal sandstone, mounted on SEM-stub, sputter-coated, Stn 5 ( OLL 2016/149).

Other material examined

ATLANTIS SMT: 1 colony on biogenic rock, Stn 3 (unregistered MNHN material); 7 colonies on stylasterid skeleton plus 3 colonies on coral skeleton, Stn 7 (unregistered MNHN material); 1 colony on coral, Stn 7 ( OLL 2016/150); 1 colony on bioclast, Stn 7 ( OLL 2016/151); 14 colonies on stylasterid skeleton, Stn 7 ( OLL 2016/152).

Description

Colony encrusting, unilaminar, multiserial, forming small patches ( Fig. 12A ). Zooids polygonal, separated by grooves; lateral walls well developed, becoming more extensive distally, gently sloping, with a single basal pore chamber connecting neighbouring zooids, communication via a round septular pore situated in centre of a large cryptocystal area with a surface similar to frontal shield ( Fig. 12E ), framed by a narrow and slightly raised ridge, only the basal part of which is gymnocystal. Frontal shield matted vitreous, convex, gently raising distally towards a short blunt central umbo on a suboral crest that is laterally gently sloping towards proximal pair of spines and distally vertically dropping towards orifice ( Fig. 12B, E ); frontal shield imperforate except for a single row of 14–18 relatively conspicuous marginal pores, surface a meshwork of faint ridges superposed by a finely granular pattern ( Fig. 12B ).

Orifice about as wide as long, rounded D-shaped with a straight or slightly concave proximal edge and a narrow shelf along distal orifice margin ( Fig. 12C ); condyles small with blunt tip; distolateral orifice margin in non-maternal zooids with seven or eight spines ( Fig. 12C, G ), potentially maternal zooids with six spines with a distinct gap between distal pair to accommodate ooecial aperture, spines particularly long (580–725 µm).

Ovicell hyperstomial, ooecium resting on or slightly immersed in distal zooid’s frontal shield ( Fig. 12B ), globular, slightly wider than long, with a very short tubular peristome wedged in between distalmost pair of spines and terminating at distal orifice margin; smooth ectooecium a relatively broad band around lower part of ooecium, narrowing proximally towards peristome; exposed endooecium extensive, imperforate, surface topography similar to that of frontal shield; ooecial aperture suborbicular, not closed by operculum.

Adventitious avicularia paired, small, oval, lateral to orifice near distolateral zooidal corners ( Fig. 12B, D ); rostrum short, semicircular to semielliptical, slightly raised distally, directing laterally or distolaterally, palate a narrow immersed distolateral shelf framing a suborbicular opesia; crossbar incomplete, composed of two short curved condyles, proximal uncalcified area semicircular ( Fig. 12F ). Interzooidal avicularia frequent in late astogenetic parts of colony, placed on large polygonal cystid with variably developed cryptocyst-type granular frontal shield and a row of five to seven, relatively large marginal pores as in autozooids ( Fig. 12E ); rostrum spatulate, slightly raised distally, of variable size and pointing in various directions, with tip reaching one of the cystid corners, most of palate occupied by a broad distal shelf narrowing proximally, distal uncalcified area large, elongate and roughly triangular; mandible hinged on short triangular condyles or on complete crossbar, proximal uncalcified area subcircular.

Ancestrula tatiform, oval (ca 460 µm long, 360 µm wide), smooth gymnocyst narrow all around, cryptocyst absent ( Fig. 12D ); opesia large (ca 330 µm long, 270 µm wide), oval, very slightly constricted in distal fifth; 13 spines, with seven proximal ones more widely spaced and six distal ones situated slightly closer together.

Remarks

The most obvious differences between Bathycyclopora suroiti gen. et sp. nov. and B. vibraculata gen. et comb. nov. are the distinctly smaller condyles, and the presence of eight spines in most zooids in the former species. Moreover, the structure of the frontal shield surface is more distinct than in B. vibraculata gen. et comb. nov., and is, especially in early ontogenetic zooids, reminiscent of the honeycomb structure of ridges in some species of Atlantisina gen. nov.

Ecology

Bathycyclopora suroiti gen. et sp. nov. occurs at depths of 275–460 m, encrusting stylasterid skeletons and other old biogenic substrata.

Distribution

The species was found on the central Atlantic Atlantis and Hyères seamounts.

Figures

Fig. 12. Baythycyclopora suroiti gen. et sp. nov., Atlantis Smt. A. Overview of a partly damaged colony (paratype, OLL 2016/149). B. Ovicellate zooids (paratype, MNHN-IB-2014-77). C. Close-up of an orifice (paratype, MNHN-IB-2014-77). D. Ancestrula and the first two autozooids (paratype, OLL 2016/126). E. Interzooidal avicularium; note the single communication pore per neighbouring zooid as well as the extensive cryptocystal calcification surrounding it and the thin peripheral band of gymnocyst (paratype, MNHN-IB-2014-77). F. Close-up of adventitious avicularium (paratype, MNHN- IB-2014-77). G. Lateral view of oral spines (holotype, MNHN-IB-2014-73). Scale bars: A = 500 µm; B, D–E, G = 200 µm; C, F = 50 µm.