Calvetopora otapostasis, 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 : 40-43

Calvetopora otapostasis gen. et sp. nov.

urn:lsid:zoobank.org:act:701FB911-9BE3-45A4-88A6-F6BB1E47CEFD

Fig. 14 A–F, Table 14

Diagnosis

Calvetopora otapostasis gen. et sp. nov. differs from the type species C. inflata gen. et comb. nov. in having distinctly larger zooids, an orifice that is longer than wide and has only three to six oral spines, in the frontal shield with its granular surface structure and a higher number of central pseudopores, and in the ooecium, which is covered by a calcified ectooecium in its lower part.

Etymology

The name alludes to the two avicularia lateral to the orifice, which look like protruding ears (Latin: otapostasis); used as a noun in apposition.

Material examined

Holotype

ATLANTIS SMT: 1 ovicellate colony on sandstone substratum, Stn 7 ( MNHN-IB-2014-78 ).

Paratypes

ATLANTIS SMT: 1 colony on stylasterid skeleton, Stn 7 (MNHN-IB- 2014-79); 1 isolated colony, Stn 7 (MNHN-IB- 2014-80); 1 colony on stylasterid skeleton showing the ancestrula and early astogenesis, Stn 7 (MNHN-IB- 2014-81); 1 coated colony on stylasterid skeleton, Stn 7 (MNHN-IB-2014-280); 3 colonies on stylasterid skeleton, Stn 7 ( OLL 2016/127); 1 colony on stylasterid skeleton, Stn 7 ( OLL 2016/153); 1 ovicellate colony on Dendrophyllia sp., Stn 3 (MNHN-IB- 2014-82).

Other material examined

ATLANTIS SMT: 4 colonies on stylasterid skeleton, Stn 7 (unregistered MNHN material); 1 ovicellate colony, Stn 8 (unregistered MNHN material); 1 colony on stylasterid skeleton, with Atlantisina atlantis gen. et sp. nov., Stn 7 ( OLL 2016/128); 1 colony on bioclast, with Bathycyclopora suroiti gen. et sp. nov., Stn 7 ( OLL 2016/151); 1 colony on stylasterid skeleton, Stn 7 ( OLL 2016/154).

Description

Colony encrusting, unilaminar, multiserial, forming relatively large patches ( Fig. 14A ), occasionally thickened owing to self-overgrowth, sometimes growing free of substratum, producing variably thick calcified extensions from basal wall that may or may not reach substratum; cuticle iridescent in dried colonies. Zooids large, oval to pentagonal or polygonal in outline, separated by shallow grooves ( Fig. 14C ); lateral walls well developed, communication via two or more basal pore chambers per neighbouring zooid, gymnocystal surface reduced, extensive areas of cryptocystal calcification with a reticulate surface, each framing a large suborbicular pore window ( Fig. 14C ). Frontal shield matted vitreous, usually very slightly convex, entirely made of thick cryptocystal-type calcification with five to eight marginal pores and between 20 to 40 pseudopores of similar size, 12–16 outermost ones generally arranged in a peripheral U-shaped row, innermost pores occasionally arranged in a similar pattern or more scattered around a central imperforated area, each pore encircled with a faint rim; surface structure rugose with superposed fine granules ( Fig. 14C ).

Orifice D-shaped, longer than wide, proximal margin fairly straight or shallowly curved ( Fig. 14D, F ); condyles inconspicuous in frontal view, formed by a slightly rounded thickening of proximal ends of lateral orifice margin; adult non-maternal zooids usually with three oral spines on distal orifice margin ( Fig. 14D ), early astogenetic zooids may have up to eight spines ( Fig. 14E ), only two spines in ovicellate zooids ( Fig. 14B ).

Ooecium produced by zooid distal to maternal one, hyperstomial, resting on the distal zooid’s frontal shield, globular, about as wide as long, with a short peristome wedged in between a pair of spines, terminating at distal orifice margin ( Fig. 14B ); ectooecium partially calcified, covering lower part of ooecium; exposed endooecium with a similar surface structure as that of frontal shield; ooecial aperture suborbicular, not closed by operculum.

Adventitious avicularia paired, ovate, situated directly lateral to orifice on a slightly raised cystid ( Fig. 14 B–D); rostrum semi-elliptical but occasionally asymmetric and slightly curved inwards, directing distally or distolaterally, often at an acute angle to frontal plane; distal uncalcified area suborbicular, palate a narrow distal shelf, mandible hinged on a pair of long and thin condyles occasionally fusing at centre, proximal uncalcified area semicircular.

Ancestrula tatiform with 11 spines, opesia oval (ca 305 µm long, 235 µm wide), constricted in distal third, gymnocyst narrowing distolaterally, cryptocyst invisible ( Fig. 14E ); first zooid budded distolaterally, with eight long spines, frontal shield with ca 12 large pseudopores and one adventitious avicularium.

Remarks

With its characteristic, large-sized and strongly calcified zooids, Calvetopora otapostasis gen. et sp. nov. forms conspicuous and extensive encrusting colonies. Self-overgrowth often resulted in plurilaminar colonies, and the species is able to bridge gaps in the substratum while forming basal struts of highly variable length and width. Some zooids also showed intramural buds within otherwise undamaged zooecia, indicated by the presence of a second orifice rim with spines.

Ecology

Calvetopora otapostasis gen. et sp. nov. was mostly found encrusting dead stylasterid skeletons at depths of 280 to 460 m.

Distribution

The species is apparently endemic to Atlantis Smt.

Figures

Fig. 14. Calvetopora otapostasis gen. et sp. nov., Atlantis Smt. A. Overview of the holotype (MNHN- IB-2014-78). B. Close-up of an ooecium and the suboral avicularia (holotype MNHN-IB-2014-78). C. Slightly oblique view of an autozooid at the growth margin showing the communication pores in the lateral walls as well as marginal areolar pores (black arrow) and the roughly crescentically arranged pseudopores (white arrows) in the frontal shield (paratype MNHN-IB-2014-280). D. Close-up of orifice; note that the condyles are so short that usually only one can be seen (paratype OLL 2016/153). E. Ancestrula and early astogenetic autozooids (paratype MNHN-IB-2014-81). F. Interior frontal shield showing the lateral areolar pores and the central pseudopores (paratype OLL 2016/153). Scale bars: A = 500 µm; B, D, F = 100 µm; C, E = 200 µm.