Fenestrulina ovata Rosso & Di Martino, 2025

Rosso, Antonietta, Di Martino, Emanuela, Donato, Gemma, Figuerola, Blanca, Gerovasileiou, Vasilis, Siddiolo, Chiara, Sinagra, Alessandro, Sanfilippo, Rossana & Sciuto, Francesco, 2025, Unlocking Mediterranean bryozoan diversity: seven new species unveiled after fixing a neotype for Fenestrulina malusii (Audouin & Savigny, 1826) (Cheilostomatida, Fenestrulinidae), ZooKeys 1254, pp. 1-74 : 1-74

publication ID	https://doi.org/10.3897/zookeys.1254.157989
publication LSID	lsid:zoobank.org:pub:959351D6-F778-4E6A-9AD5-97B9A190E0A7
DOI	https://doi.org/10.5281/zenodo.17237601
persistent identifier	https://treatment.plazi.org/id/F1AAED4E-3B0A-551B-A7F4-D257B9737D50
treatment provided by	ZooKeys by Pensoft
scientific name	Fenestrulina ovata Rosso & Di Martino
status	sp. nov.

Treatment

Fenestrulina ovata Rosso & Di Martino sp. nov.

Figs 1 View Figure 1 , 16 View Figure 16 , 22 View Figure 22 , 23 View Figure 23 ; Tables 1 View Table 1 , 4 View Table 4

Type material.

France • Holotype 1 ovicellate, lobate, locally multilaminar owing to self-overgrowth colony, encrusting the inner side of a cemented bivalve on an old coralligenous concretion. Mediterranean, Liguro-Provençal basin, Cassis, calanque of Port Miou , Stn-JGH- 73.06; 43°12'12.00"N, 5°30'51.74"E; 17 m depth; 18 Mar. 1973; J.-G. Harmelin leg.; PMC.B 42.23.10.2024.a GoogleMaps . France • Paratypes 3 ovicellate colonies on the same coralligenous concretion; same details as the holotype; PMC.B 42.23.10.2024.b 1 –3 GoogleMaps . France • 9 ovicellate multilaminar colony fragment detached from its substrate. Mediterranean, Liguro-Provençal basin, Cassis, Trémies cave, left chamber ; 43°12'00"N, 5°30'50"E; 6 m depth; 2 May 1985; scuba diving; J.-G. Harmelin leg.; PMC.B 42.23.10.2024.b 4 –12 GoogleMaps . France • 6 ovicellate multilaminar fragmentary colonies on small limestone substrates. Mediterranean, Liguro-Provençal basin, Cassis, Trémies cave, dark zone B ; 43°12'00"N, 5°30'50"E; 8 m depth; 7 Jan. 1982; scuba diving; J.-G. Harmelin leg.; PMC.B 42.23.2.2024.b 13 –18 GoogleMaps .

Diagnosis.

Fenestrulina with multilaminar colonies owing to self-overgrowth; relatively wide and flat autozooids; numerous, small subcircular to trifoliate pseudopores with 2–4 spiny, radial processes unfused centrally, arranged in 1–3 rows between orifice and ascopore and one or two marginal, often complete, rows along the barely visible cryptocystidean rim; 1–3, very distal oral spines; arcuate ovicell lateral lappets overarching lateral sides of orifice.

Description.

Colony encrusting, multiserial, lobate, multilaminar owing to self-overgrowth (Fig. 16 A, D View Figure 16 ), ~ 1 cm 2 in size.

Autozooids rounded hexagonal or irregularly shaped, distinct, with very narrow, deep grooves marking the boundaries (Fig. 16 B – E View Figure 16 ). Lateral and proximal walls deeply sloping to sub-vertical, only locally exposing their upper parts, mostly at corners. Frontal shield nearly flat with faint dimpled appearance, more marked centrally in slightly elevated ascopore zone. Gymnocyst forming a narrow rim of calcification distal and lateral to orifice. Cryptocystidean area extensive, almost undefined, mirroring autozooidal boundary and proximal and lateral margins of orifice, lining it in non-ovicellate autozooids, slightly diverging laterally in ovicellate ones (Fig. 16 E View Figure 16 ), forming subtriangular latero-oral extensions, longer in non-ovicellate autozooids (110–152 μm long), usually reaching the distal orifice margin. Pseudopores of the frontal shield arranged in a peripheral row of ~ 20, usually adjacent to frontal edge, more spaced proximally (Figs 16 C – F View Figure 16 , 23 G View Figure 23 ), with some sparse pseudopores forming an additional discontinuous row. Two, rarely three, additional rows of pseudopores (9–14) between orifice and ascopore. Pseudopores on a level with frontal surface, subcircular to trifoliate, with 2–4 spiny radial processes unjointed centrally (Fig. 16 G, H View Figure 16 ). Two (occasionally 1 or 3) circular to elliptical cryptocystidean areas, lined by an elevated rim, distal to orifice, each with a single pseudopore and numerous spiny processes (Fig. 16 D, E – G View Figure 16 ).

Primary orifice transversely D-shaped, hinge-line straight, with smooth thin rim; proximal and distal rims smooth, with very low shoulders at proximal ends. Two, occasionally one or three, thin and short oral spines (base diameter ~ 12 μm) distal to orifice (Fig. 16 F – I View Figure 16 ), sometimes four in periancestrular autozooids; two spines laterally and proximally displaced, barely visible in ovicellate zooids (Fig. 16 E View Figure 16 ).

Ascopore placed slightly distal to autozooid centre, at variable distance (84–126 μm) from the orifice (Fig. 16 C – H View Figure 16 ), lumen transversely C-shaped (Fig. 16 G, H View Figure 16 ), wide, with finely denticulated rim, situated in a sub-circular to transversally elliptical field of smooth gymnocyst marked by a smooth raised rim, fusing with arched proximal rim of frontal shield in the presence of an ovicell (Fig. 16 D View Figure 16 ).

Ovicell subglobular, prominent, obscuring the distal part of orifice, with lateral lappets forming an overarching ovate-like structure (Fig. 16 C – E View Figure 16 ), seemingly subcleithral, only partly closed by the operculum, produced by the distal autozooid (Fig. 16 B – D View Figure 16 ). Endooecium well calcified, dimpled centrally, becoming smoother and intumescent peripherally and proximally, ending in a narrow rim folding upward; rimmed by a row of 15 or more marginal pores (12–40 μm wide, occasionally up to 96 μm). Ectooecial margin comprising a very low, thin gymnocystal arc curving across frontal surface of distal autozooid (Fig. 16 D View Figure 16 ).

Ancestrula covered by self-overgrowing colony lobes.

Kenozooids not observed.

Etymology.

From the Latin ovatus, meaning egg-shaped, referring to the overall shape of the ovicell created by the lateral lappets.

Remarks.

Fenestrulina ovata sp. nov. resembles F. juani , F. cavernicola sp. nov., and F. foveolata sp. nov. in its ornamented frontal surface, particularly sharing the dimpled appearance of the ovicell surface with the latter. However, it can be easily distinguished from these species. The prominent ovicell ornamentation, the morphology of both the ascopore and the frontal pseudopores, and the presence of bifurcated spines set it apart from F. juani . The combination of a spiny ovicell, a large fissure separating the endooecium and ectooecium, and long lateral lappets deeply indented by prominent, large spines distinguishes F. cavernicola sp. nov. The prominent, bifurcated spines, even in ovicellate autozooids, are typical of F. foveolata sp. nov.

Lateral lappets of the ovicell extending to the proximal border of the orifice are also observed in other species, mostly from the Southern Hemisphere. Fenestrulina ampla Canu & Bassler, 1928 , from a depth of 120 m off Brazil, has smooth frontal shields and ovicells, with stellate pseudopores commonly found on the proximal part of the autozooids. Similarly, F. antarctica has ovicells that extend over the proximal rim of the orifice. However, it lacks lateral lappets, and the ovicell surface is granular unlike F. ovata sp. nov. (see also Remarks of F. granulosa sp. nov.). Fenestrulina catastictos Gordon, 1984 , from the Kermadec Ridge, also has proximally extending ovicells, which, however, feature a complex and prominent ornamentation, as well as pseudopores similar to those of the autozooids. This species also has numerous pseudopores, initially open in young autozooids and later occluded, distributed on the entire frontal shield, a distinct ribbon-like cryptocystidean area distal to orifice, and lacks oral spines. Fenestrulina epiphytica Hayward & Ryland, 1995 , from the Great Barrier Reef, Australia, has large, flat and smooth ovicells reaching the proximal border of the orifice. This species also has autozooids with smooth frontal shields, a row of peripheral pseudopores encircling the orifice also distally, and doubling between the orifice and the ascopore, which is crescentic and smooth-rimmed.

Autozooids in F. ovata sp. nov. exhibit considerable size variability and may develop irregular shapes, including proximal cauda-like extensions (Fig. 16 B View Figure 16 ) or pointed proximal corners wedged between adjacent modules (Fig. 16 C View Figure 16 ). Deformed autozooids, including giant forms (Fig. 16 D View Figure 16 , centre) or those with abnormally large latero-oral lappets extending distally to encircle the orifice (Fig. 16 D View Figure 16 , arrowed) have been observed. These deformities are similar to those observed in F. communis sp. nov. Evidence of regeneration, although rarer than in other species like F. variorugosa sp. nov., includes intramural budding with partial reconstruction of the frontal shield (Fig. 16 D View Figure 16 ) or the simple oral rim (Fig. 16 E View Figure 16 , left ovicellate autozooid). Notably, F. ovata sp. nov. demonstrates the ability to self-overgrow forming multilayered colonies, with autozooids elevating above parental ones and laterally overgrowing adjacent zooids (Fig. 16 D View Figure 16 ). This feature, to our knowledge previously unreported in Fenestrulina species, may offer an advantage in cave colonisation. Similar to other bryozoans adapted to cryptic and cave habitats, such as Onychocella marioni Jullien, 1882 ( Harmelin 1985; Rosso et al. 2019 b, 2020), this strategy likely aids in maintaining colony space and elevating the living layer into the water flow, thereby enhancing feeding opportunities in food-depleted submarine cave environments.

A colony encrusting a large, broken piece of pottery collected at 23 m depth in the Gulf of Fos by J.-G. Harmelin, remains of uncertain attribution. The dimpled frontal shield resembles that of F. ovata sp. nov. or F. foveolata sp. nov. but the few preserved spines are not bifurcating unlike F. foveolata sp. nov., making the attribution to F. ovata more plausible. However, the absence of ovicells and the inability to perform SEM examination, due to the large size of the substrate that cannot be reduced without risking damage to the colony, preclude definitive identification.

Habitat distribution.

Fenestrulina ovata sp. nov. has so far been found in different habitats and contexts, all characterised by a reduction of light at relatively shallow depths ( 6–23 m). Colonies seem to be relatively common in submarine caves in completely dark zones ( 6 m), as well as in cryptic microhabitats in coralligenous concretions ( 17 m). The schiaphilic preferences of F. ovata sp. nov. are also indicated by its occurrence on the underside of a rock in coarse sedimentary bottoms at 23 m depth.

Geographical distribution.

Fenestrulina ovata sp. nov. has currently been found only in localities in the Gulf of Lion, in the northern sector of the Liguro-Provençal basin.