Fenestrulina foveolata Rosso & Di Martino sp. nov.

Figs 1, 13, 22, 23, 24; Tables 1, 3

Type material.

France • Holotype colony including the ancestrula and some ovicells on fronds of Laminaria rodriguezii . Mediterranean, Liguro-Provençal basin, NW Corsica, Ile-Rousse Bank; coordinates not available; 85–100 m depth; 5 Aug. 1957; R/V Président Théodore Tissier survey, St. 423; J.-G. Harmelin leg.; PMC.B 40.23.10.2024.a . France • Paratypes 17 additional colonies and isolated autozooids; same details as the holotype; PMC.B 40.23.10.2024.b .

Diagnosis.

Fenestrulina with partly exposed lateral walls; dimpled frontal shield and ovicell endooecium; endooecium lined by a row of ~ 15 small peripheral pores and a smooth, low rim of ectooecial calcification; a few tri- to quadrifoliate pseudopores restricted to the distal half of autozooids; transversely C-shaped denticulate ascopore within a subcircular to transversely elliptical gymnocystal field; three or four stout spines, the proximalmost pair bifurcated.

Description.

Colony encrusting, multiserial, unilaminar; interzooidal communications via one proximal, two proximolateral, two (occasionally 3 or 4) distolateral, and one distal pore-chamber.

Autozooids ovoidal to round hexagonal, distinct, boundaries marked by narrow, deep grooves (Fig. 13 A, B). Lateral and proximal walls steeply sloping to sub-vertical, exposing only their upper parts, generally more expanded and more gently sloping at corners. Frontal shield slightly convex, more elevated at ascopore level, with a dimpled texture, particularly near the ascopore. Gymnocyst forming a discontinuous narrow rim distal and lateral to orifice. Cryptocystidean area extensive, outlined by a raised edge-line, mirroring autozooidal boundary and proximal and lateral margins of orifice, lining it or slightly diverging distalwards in non-ovicellate autozooids, diverging much more in ovicellate ones (Fig. 13 C – E), forming subtriangular latero-oral extensions (56–106 μm long), longer in non-ovicellate autozooids. Pseudopores of the frontal shield arranged in a single lateral row of 8–12, irregularly spaced in the distal half of autozooid, absent proximally (Fig. 13 A – F), often adjacent to the frontal edge. Two, rarely three, additional rows of pseudopores (6–17) occurring between orifice and ascopore. Pseudopores on a level with frontal surface, spiculate, typically tri- to quadrifoliate, with two to five compressed spiny processes projecting centrally but unjointed (Figs 13 C, 23 D). Two circular-elliptical cryptocystidean areas, lined by an irregularly lobate rim, occur distal to the orifice, each area seemingly including a single pseudopore or fused pseudopores with numerous spiny processes (Fig. 13 D).

Primary orifice transversely D-shaped, hinge-line straight, lined by a thin, smooth rim; proximal and distal rims hidden by opercula. Three, occasionally four, tubular and relatively stout oral spines, up to 80 μm long and 15–20 μm in diameter, placed distally and / or distolaterally (Fig. 13 B – E); periancestrular autozooids usually with four spines (Fig. 13 F), the proximalmost pair more developed and bifurcated, branches facing upwards; proximalmost bifurcated spines persisting in ovicellate zooids, with distal branches almost leaning against the ovicell (Fig. 13 B, E).

Ascopore placed slightly distal to autozooid centre, at variable distance (80–118 μm) from the orifice (Fig. 13 C – D), lumen transversely C-shaped, with finely denticulated rim, situated in a sub-circular to transversally elliptical field of smooth gymnocystal calcification marked by a smooth raised rim, often fusing with the arched proximal rim of the frontal shield in the presence of an ovicell (Fig. 13 E).

Ovicell subglobular, prominent, slightly obscuring the distal part of the orifice, with short lateral lappets not indented by oral spines, proximolateral corners remaining distal to the spines on each side, seemingly subcleithral, only partly closed by the operculum, produced by the distal autozooid (Fig. 13 B, E). Endooecium well calcified, with a dimpled surface similar to autozooid frontal shield, proximally smoother, its narrow rim folding upward; rimmed by a ~ 30 μm large depression, largely filled by endooecial calcification interrupted by 15 or more marginal pores. Ectooecium consisting of a thin, prominent, raised gymnocystal rim, leaning against the proximal frontal raised edge of the distal autozooid (Fig. 13 E).

Ancestrula tatiform (Figs 13 F, 24 E), with a narrow cryptocystidean rim encircled by ten spines: four distal, more closely spaced; six lateral and proximal, more widely spaced. Budding pattern: one distal, two distolateral and, subsequently, two proximolateral zooids along with a larger proximal autozooid, forming a ring of six periancestrular autozooids.

Kenozooids not observed.

Etymology.

From the Latin fovea, meaning pit, alluding to the dimpled surface of both the frontal shield and the ovicell endooecium.

Remarks.

Fenestrulina foveolata sp. nov. mostly resembles F. cavernicola sp. nov. but differs in having a distinct ornamentation of the ovicell, with short, non-indented lateral lappets rimmed by a row of small peripheral pores, fewer frontal pseudopores, absent proximally, and more often adjacent to the gymnocystal margin, smaller autozooids, orifices, and ascopore field, and proximal oral spines well developed and bifurcated. A dimpled, but less pronounced, ooecial surface also occurs in F. ovata sp. nov., which, however, lacks bifurcated spines and has spine bases only barely visible in ovicellate autozooids. This species also has an ovicell with arcuate lateral lappets overarching the lateral sides of the orifice, absent in F. foveolata sp. nov. The dimpled surface of both autozooids and ovicells is also reminiscent of F. gelasinoides, but that species has stronger ornamentation, occluded autozooidal pseudopores and inconspicuous, unbranched oral spines in ovicellate autozooids. Based on Gautier’s (1962) report of a bifurcate proximal pair of oral spines (p. 170) and of deep colonies with a more granulose frontal shield (p. 171), at least some of his F. malusii material may belong to this species or to F. kalliste sp. nov.

Habitat distribution.

Fenestrulina foveolata sp. nov. has been found only on Laminaria fronds, co-occurring with F. malusii .

Geographical distribution.

Fenestrulina foveolata sp. nov. is currently known only from its type locality off Corsica (Ile-Rousse Bank), in the Liguro-Provençal basin.