Fenestrulina variorugosa Rosso & Di Martino 2025, sp. nov.

Fenestrulina variorugosa Rosso & Di Martino sp. nov. Figs 1, 17, 18, 19, 20, 22, 23, 24; Tables 1, 4 Fenestrulina malusii (Audouin): Zabala et al. 1993: list of species; Chimenz Gusso et al. 2014: 166 (pars), fig. 83 a, b. Type material. Italy • Holotype 1 large ovicellate colony without ancestrula on a rhizome of Posidonia oceanica (Linnaeus) Delile. Mediterranean, Sicily Strait, W Sicily, Egadi Islands, Formica Isle, sample EFI 20; 37°59'14"N, 12°25'34"E; 8 m depth; Oct. 2007; scuba diving; A. Sinagra leg.; PMC.B 43.23.2.2024.a. Italy • Paratype 1 juvenile colony including 15 non-ovicellate autozooids around the ancestrula; same details as the holotype; PMC.B 43.23.2.2024.b.1. Other material examined. Italy • 2 living colonies on the shell of a living specimen of Lithophaga lithophaga (Linnaeus, 1758). Mediterranean, Italy, Tyrrhenian Sea, NE Sicily, Secca di Levante, Capo Milazzo Peninsula, sample MI_SdL_G; 38°14'43"N, 15°14'26"E; 33 m depth; Coralligenous biocoenosis; 17 May 2024; scuba diving; G. Donato leg.; PMC Rosso-Collection I.H.B.160.a.1 a. Italy • 5 living colonies on a soft-bodied alga. Mediterranean, Italy, Tyrrhenian Sea, NE Sicily, Secca di Ponente, Capo Milazzo Peninsula, sample MI_SdPn_G; 38°16'28"N, 15°13'22"E; 33 m depth; Coralligenous biocoenosis; 6 May 2024; scuba diving; G. Donato leg.; PMC Rosso-Collection I.H.B.160.a.1 b. France • 1 living colony with only few functional autozooids on a dead coral fragment. Mediterranean, Liguro-Provençal basin, Cassis, Cassidaign Canyon; no coordinates available; 300 m depth; Bathyal Corals biocoenosis; 21 Jun. 1969; J.-G. Harmelin leg.; PMC J-GH-Collection F.H.B.160.b.1. France • 5 living ovicellate and non-ovicellate colonies on a bioconcretion of white corals hosting a few Crania anomala (Müller, 1776) specimens and several cryptic arciid and mytilid bivalves, with 1 out of 5 colonies encrusting the outer shell of an arciid. Mediterranean, Liguro-Provençal basin, off Banyuls-sur-Mer, sample 5; 42°4.30'N, 3°25'E; 200–300 m depth; Bathyal Corals biocoenosis; Jun. 1984; J.-G. Harmelin leg.; PMC J-GH Collection F.H.B.160.c. France • 1 living colony encrusting the underside of a stone. Mediterranean, Liguro-Provençal basin, Port Cros Park, Cave of the Bagaud Island; 43°00.9'N, 6°21.6'E; 7 m depth; June 1984; J.-G. Harmelin leg.; PMC J-GH Collection F.H.B.160.d. France • 1 living colony encrusting the inner surface of an empty shell of a dead Pinna nobilis (Linnaeus, 1758). Mediterranean, Liguro-Provençal basin, Veyron Plateau, off Marseille; coordinates not available; 24 m depth; 23 Sep. 1983; J.-G. Harmelin leg.; PMC J-GH Collection F.H.B.160.e. Tunisia • 2 colonies. Mediterranean, Sicily Strait, off Tabarka; coordinates not available; 86 m depth; J. Jullien Collection; MNHN_IB_2008_2590. Diagnosis. Fenestrulina with lobate pseudopores characterised by three or four irregularly curving spinules, thickening and flattening towards the centre without meeting, arranged in a single row, some becoming semicircular, leaning against rim of frontal shield; globose ovicell rimmed by several small peripheral pores with variable endooecial ornamentation, ranging from gently nodular, to faintly ribbed and scalloped at the periphery, or prominently rough with radial crests. Description. Colony encrusting, multiserial, unilaminar (Fig. 17 A), irregularly shaped in relation to the substrate morphology, ~ 1 mm in diameter. Interzooidal communications via pore-chambers, two proximolateral, two distolateral (130–150 μm), one distal (~ 120 μm) (Figs 18 A, B, E, 19 C, F), each with 6–10 round pores, 6–9 μm in diameter (Fig. 18 B). Autozooids hexagonal, distinct, contiguous, boundaries marked by narrow, deep grooves widening at triple junctions, exposing upper parts of sub-vertical lateral walls (Figs 17 B – E, 19 A – E). Frontal cryptocystidean area outlined by a thin, slightly raised rim, more pronounced at pseudopore level, lining orifice proximally and laterally, developing long (mean length 148 μm, n = 11) lappets on both sides of orifice (Figs 17 B – E, 18 A, F, G, 19 A – C, F, G). These lappets occasionally extending distally and almost encircling the orifice but never joining (Fig. 19 A). Two elliptical, occasionally one elongate, cryptocystidean areas distal to the orifice, between oral spines, each with one or two pseudopores, rarely more (Figs 17 B – E, 18 A, C, F, 19 F, G). Frontal surface gently convex, more raised at ascopore level, smooth, perforated by 32–45 pseudopores, 12–20 in periancestrular autozooids (Figs 18 E, 19 C). Pseudopores mostly located in distal half of autozooid, arranged in two rows between orifice and ascopore, one or two rows in lateral lappets (Figs 17 B, E, 18 A, C, F), in a single row along lateral zooidal margins, sparse or absent proximally (Figs 17 C – E, 19). Pseudopores on a level with frontal shield, irregularly subcircular to slightly lobate, semicircular (Figs 17 D, 19) or slit-like (Fig. 17 E) along lateral rim; each with three or four (rarely more) spinules projecting, thickening and flattening or branching centrally, never merging (Figs 18 C, D, F, 23 H). Circular pseudopores without spinules in regenerated autozooids in damaged colony areas (Fig. 20 C – F), sometimes occluded by underlying gymnocystal calcification (Fig. 20 D, E). Basal wall largely uncalcified. Primary orifice transversely D-shaped, hinge-line straight with two tiny denticles near proximal corners; distal rim fairly denticulated (Fig. 18 C). Two oral spines in most autozooids (Figs 17 B – E, 18 C, F, G), rarely three (Figs 18 G, 19 G), four observed in the first periancestrular ones (Fig. 18 E), ~ 100 μm long (base diameter 15–25 μm), located along distal curvature (Figs 17 B – E, 18 C, G). Intrazooidal regeneration may alter spine count (e. g., Fig. 18 F). Only two, barely visible, spines in ovicellate autozooids, lining ovicell margins near proximal rim (Figs 17 C, D, 19 D, H). Ascopore ~ 90 μm proximal to orifice (Figs 17, 18 A, C, D, G, 19 F, G), within a reniform field of smooth gymnocyst marked by a slightly raised rim, in contact with the arched proximal rim of the frontal shield in the presence of an ovicell (Fig. 17 E) or fusing with it (Fig. 19 D, H); large transversely C-shaped lumen between the distal wide tongue and the arched proximal border; rim irregularly denticulated including tiny spindle-like spinules and larger, platy to branched denticles (Figs 17 B, E, 18 C, D, 19 F, G). Ovicell subglobular, prominent, restricted proximally to fit orifice width, slightly obscuring distal part of orifice, not closed by the operculum, produced by the distal autozooid (Figs 17 C, D, 19 D, H). Endooecium well calcified, gently nodular and faintly ribbed and scalloped to prominently rough with blunt spiny processes and radial crests at periphery but smoother proximally; rimmed by a row of ~ 15 quadrangular pores, separated by calcified bridges, often reduced in diameter by secondary calcification (Fig. 17 C, arrowed); proximal margin with narrow upturned rim just at corners above oral spines. Calcified part of ectooecium consisting of a narrow (~ 30 μm) elevated rim of gymnocyst lining the row of pores. Ancestrula tatiform (Figs 18 E, 19 C, 24 F, G), irregularly oval, similar size to first periancestrular autozooids, gymnocyst apparently narrow, largely covered by periancestrular autozooids in examined material, with ten spines: five around orifice (three distal, closely spaced, two more proximally placed, at a greater distance, aligned with proximal margin of operculum), five around proximal half of opesia (widely and regularly spaced). Opesia oval (305 μm long by 220 μm wide) surrounded by a narrow (~ 15 μm), almost smooth cryptocyst. Two longitudinally elongated cryptocystidean areas (2 or 3 pores each) between distal triad and two more proximal oral spines (Fig. 18 E). Budding pattern: one distal, two distolateral, two proximolateral and two proximal autozooids (Fig. 18 E). Kenozooids small, triangular to quadrangular, elongate, filling empty spaces between autozooids in areas without evidence of reparation, including few relatively large pseudopores with 5–7 denticles giving a stellate appearance (Figs 18 G, 19 H). Etymology. Referring to the variability of the ovicell ornamentation, especially the variable degree of the endooecial rugosity. Remarks. Fenestrulina variorugosa sp. nov. resembles F. barrosoi Álvarez, 1993, an Atlanto-Mediterranean species described from the Alboran Sea at depths of 15–20 and 50–60 m (Álvarez 1993), and later recorded at 112–120 m depth (Ramalho et al. 2022), and from the Galician coast on seagrasses at ~ 15 m depth (Reverter Gil et al. 2019). Both species share the general morphology of ovicells and autozooids, including the shape and location of the ascopore. However, all morphological measurements, except for the autozooidal length of the holotype, tend to be smaller in F. barrosoi than in F. variorugosa sp. nov. In F. barrosoi, pseudopores are always distributed in a single row along lateral and proximal margins, without any doubling or absence in these areas, as observed in F. variorugosa sp. nov. Fenestrulina barrosoi typically has 3–6 oral spines, most commonly four or five based on Álvarez (1993: 833), although his fig. 1 on p. 832 shows zooids with three spines, rather than the 2–4 (mostly two), seen in F. variorugosa sp. nov. Importantly, the proximal pair of spines in F. barrosoi is stout and shifted proximally. Colonies with rugose ovicells resemble F. kalliste sp. nov., but the latter species has heavier ornamentation, with more developed spiny processes and a central area with prominent and often transversal crests. The pseudopore number, distribution and morphology differ significantly, and the proximal oral spines in F. kalliste sp. nov. are bifurcated. Rough ornamentation of the endooecium is also seen in F. cavernicola sp. nov. and F. juani, but in these species, the frontal shield is dimpled. In F. ca