Collarina speluncola Harmelin, 2019

Harmelin, Jean-Georges, Bishop, John D. D., Madurell, Teresa, Souto, Javier, Spencer Jones, Mary E. & Zabala, Mikel, 2019, Unexpected diversity of the genus Collarina Jullien, 1886 (Bryozoa, Cheilostomatida) in the NE Atlantic-Mediterranean region: new species and reappraisal of C. balzaci (Audouin, 1826) and C. fayalensis Harmelin, 1978, Zoosystema 41 (21), pp. 385-418 : 404-406

Collarina speluncola Harmelin , n. sp.

( Figs 8C ; 13 ; 15A ; 17E ; 18B ; Tables 1-3 )

urn:lsid:zoobank.org:act:9FCF7C95-06C5-4FFF-A4E1-701C4E070962

TYPE LOCALITY. — France, Marseille, Calanques Coast.

TYPE MATERIAL. — Holotype. France, Marseille , Calanques Coast, Conger Cave, dark chamber, 43°12’34”N, 5°27’47”E, 3 m, 2.VI.1987, coll. by JGH, 1 ovicelled colony (c. 160 zooids, circled in red) together with 2 smaller colonies, on fragment of rocky wall, MNHN- IB-2014-1912.

Paratypes. Same data as the holotype. MNHN-IB- 2014-1913: 5 alive + 3 dead colonies, on wall fragment . — MNHN-IB- 2014-1914: 12 colonies, on wall fragment . — MNHN-IB- 2014-1915: 3 coated colonies (JGH stubs 64 & 72) .

OTHER MATERIAL EXAMINED. — Same data as the holotype and paratypes, many colonies, MNHN, NHMUK . — France. La Ciotat, Gameau Cave , dark chamber, 43°09’53”N, 5°35’56”E, 2 -3 m, VII.1992, coll. by JGH, 5 colonies on fragments of rocky wall; MNHN . — Monaco. jetty outer side, 18 m, 18.X.1997, coll. by JGH, 1 colony on pebble from boulder piling, MNHN . — Atlantic. Portugal , Sagres , Ponta da Baleeira, Donzelle Cave, 37°00’17’’N, 8°55’43’’W, 4 m, 8.VII.1986, coll. by JGH, 3 colonies on dead coral in dark chamber, MNHN .

ETYMOLOGY. — From Latin noun spelunca: cave. Named for the preference of this species for dark marine caves.

DIAGNOSIS. — Colonies medium- to large-sized. Autozooids with marginal gymnocyst visible frontally, costate shield moderately convex, made of numerous costae without protuberances, separated by small lacunae forming several concentric rings; apertural bar moderately raised; orifice with clearly visible condyles delimiting a proximal part (poster) broader than the anter and slightly convex; 3-5 thin oral spines; adventitious avicularia mostly single or paired, directed laterally or slightly disto-laterally; ooecium formed by distal kenozooid, with smooth ectooecium; ancestrula with 8 spines (occasionally 7).

DESCRIPTION

Colonies encrusting, pluriserial, unilaminar, medium- to largesized (i.e.> 150 zooids) when fully grown, irregularly shaped but often elongated, white in young parts, brownish when older due to exogenous metallic coating. Autozooids longer than wide, surrounded by 7-8 pore-chambers (1 or 2 distal) visible at the growing margin; peripheral gymnocyst generally clearly visible frontally, wider proximally ( Fig. 13A, C ). Costal shield (spinocyst) weakly convex, smooth, composed in most zooids of 15-16 costae (14-20) ( Fig. 13A ). Costae faintly prominent, their layout forming a relatively smooth surface except for a slightly raised bulge corresponding to the midline fusion of costae on the distal half of the costal shield of some zooids ( Fig. 13A, C ); intercostal lacunae small (5-8 Μm), rounded, 3-4 between adjacent costae; a relatively large pelma (diameter twice that of lacunae) at the base of each costa, its edge slightly prominent and funnel-shaped, i.e., with a rounded external orifice larger than an internal one (12-15 vs 5-8 Μm); a second pelma occasionally present close to the middle line of the shield. Apertural bar forming a thick, roughly triangular bulge, more or less irregularly shaped, often with a slight concavity on the proximal side, a pair of pelmatidia opening upwardly at the tip and a large pelma on each side of the bar, these pseudopores often being hidden by calcification ( Figs 8C ; 13B). Adventitious avicularia present in most autozooids (70%), generally single (80%), more rarely paired (20%), inserted at the lateral corners of the apertural bar, directed laterally or slightly laterodistally, with pointed mandible and large, half-oval, proximal area ( Figs 8C ; 13A), occasionally with nested cystids ( Fig. 17E ). Autozooidal orifice wider than long (W/L = 1.2; Table 1 ), with the maximum width below the condyles, i.e., between the two rounded proximal corners of the orifice ( Figs 8C ; 13B), broader (> 20- 25%) in ovicelled zooids ( Fig. 13C ); condyles thick, with a rounded tip; proximal edge slightly convex in most cases, sometimes indented in the middle by a small notch. Oral spines thin, 3-5 in number, 4 in most cases, inserted on the distal half of the orifice edge, 2 in ovicelled zooids ( Fig. 13B, C ). Ovicell prominent, globose, seemingly cleithral, ooecium formed by distal kenozooid ( Figs 13C ; 15A ), slightly wider than long (W/L = 1.1; Table 1 ), smooth ectooecium punctuated with 12-16 large pseudopores similar to those of the spinocyst (i.e., pelmata with double orifice); apical aventitious avicularium directed distally, rarely present (on c. 3% of ovicells). Occasional occurrence of twin ovicells ( Fig. 13D ) with the additional one associated to a large kenozooid visible frontally, budded by the maternal zooid from a laterodistal pore-chamber. Ancestrula cribrimorph with costate shield composed of 7-9 costae including the primary apertural bar, occupying slightly over half of the frontal area, 8 spines evenly distributed around the orifice ( Fig. 13E ).

REMARKS

Collarina speluncola Harmelin , n. sp. differs from the other Collarina species of the Atlantic-Mediterranean region first by the general appearance of zooids given by a slightly convex spinocyst made of numerous smooth costae, the shape of the orifice with a broad poster, thin oral spines and ancestrula with 8 spines. The occurrence of twin ovicells, only observed at the type-locality, may be induced by local site peculiarities (see below). These features were constant in colonies from two submarine caves of the Marseille area (including the typelocality) where C. speluncola Harmelin , n. sp. forms large aggregations (see below), but also in colonies from Monaco and Sagres (S Portugal). The main difference shown by the Atlantic colonies was the number of spines, in most zooids 3 instead of 4 in the Mediterranean colonies. The apparent similarity between C. speluncola Harmelin , n. sp. and Collarina sp. awaits further investigation pending more abundant material. Seemingly, there is no indication in the literature of previous records of this species.

Habitat and geographical distribution. Most material of C. speluncola Harmelin , n. sp. came from dark caves where this species occupied vertical walls ( Fig. 18B ). In both Conger Cave (type locality) and Gameau Cave, the local population was very abundant and formed a typical ‘facies’ ( Pérès & Picard 1964), i.e., an aggregative concentration of colonies that contrasted with the quasi-absence of other encrusters, except for Haplopoma cf. graniferum (Johnston, 1847) , which presented the same growth-form. The microenvironment on cave walls densely populated by C. speluncola Harmelin , n. sp. was characterized by complete darkness and freshwater seep- age. In Conger Cave, where seepage was particularly active, salinity of the water body close to the Collarina facies was 30.6-32.0 instead of 38.6 outside the cave (measured on June 2nd 1987). In both C. speluncola Harmelin , n. sp. and H. cf. graniferum , the brown colour of the oldest parts of colonies was due to coating by Fe-Mn oxides, as commonly observed on organic and inorganic substrates from dark habitats as well in the coastal zone as in the deep sea ( Allouc & Harmelin 2001). No freshwater seepage was noticed during the sampling survey in the dark caves of Sagres, including Donzelle Cave (Boury-Esnault et al. 2001) where a few colonies of C. speluncola Harmelin , n. sp. were found in a dark, upper chamber communicating with the main chamber by a narrow corridor, together with Puellina (Cribrilaria) saldanhai Harmelin, 2001 . The colony from Monaco was not collected in a cave but encrusted the lower face of a pebble found below a jetty boulder, i.e., a discrete cryptic habitat. Freshwater seepage was not observed at this site but light occasional infiltration may occur. However, the habitat of this specimen is similar to that of Collarina sp. suggesting that the morphological and molecular relationships between the latter and C. speluncola Harmelin , n. sp. should be investigated (see below).

The known geographical range of C. speluncola Harmelin , n. sp. is limited, including only three sites in the NW Mediterranean (Marseille area and Monaco) and one in the southern Atlantic coast of the Iberian Peninsula (Sagres).

Figures

FIG. 1. — Savigny’s drawings (1817: pl. 9). Flustra balzaci Audouin, 1826, in Savigny’s figure 8, and Flustra jauberti Audouin, 1826, in Savigny’s figure 9.

FIG. 13. — Collarina speluncola Harmelin,n. sp.: A, portion of colony with ovicelled and non-ovicelled autozooids; B, distal part of a non-ovicelled autozooid,note the particular shape of the proximal edge of the orifice and the small diameter of the basal part of oral spines;C, ovicelled zooid with paired adventitious avicularia, a distal avicularium on the ooecium and a well developed gymnocyst; D, ovicelled zooid with twin ovicells, the additional one with a large kenozooid; E, ances- trula with height spines (one broken). Origin:paratype MNHN-IB-2014-1915, Marseille,Morgiou,Conger Cave. Scale bars: A, 200 µm; C, D, 100 µm; B, E, 50 µm.

FIG. 15. — Types of ooecia in Collarina Jullien, 1886 species: A-C, kenozooidal ooecia with and without distal avicularium (A, C. speluncola Harmelin, n. sp; B, C. fayalensis Harmelin, 1978; C, C. macaronensis Harmelin, n. sp.); D, C. denticulata Harmelin, n. sp., colony portion with two kenozooidal ooecia (left) and three ooecia incorporated in distal autozooid (right); E, C. macaronensis Harmelin, n. sp., 2 ovicelled zooids with kenozooidal ooecium (left) vs ooecium incorporated in distal autozooid (right). Origin: A, Marseille, Conger Cave; B, Azores, Saô Miguel, Vila Franca Is.; C, E, Madeira, NHMUK 1911.10.1.705; D, Catalonia, Medes Is. Scale bars: A-C, E 100 µm, D, 200 µm.

FIG. 17. — Adventitious avicularia with nested cystids in Collarina Jullien, 1886 species: A, C. macaronensis Harmelin, n. sp., ovicelled zooid; B, C. gautieri Harmelin, n. sp., four piles of nested avicularian cystids adventitious on two autozooids and an ooecium; C, C. macaronensis Harmelin, n. sp.; D, C. fayalensis Harmelin, 1978; E, C. speluncola Harmelin, n. sp. Origin: A, Madeira, NHMUK 1899.7.1.2105; B, Galicia, Ria de Ferrol, MHNUSC-Bry-113; C, Galicia, Sisargas Is., MHNUSC-Bry-662; D, Azores, Saô Miguel, Vila Franca; E, Marseille, Conger Cave. Scale bar: A, 100 µm.

FIG. 18. — Habitats of Collarina species:A, C. balzaci (Audouin,1826), bundles of Posidonia leaves; B, C. speluncola Harmelin,n. sp., wall of dark submarine cave with freshwater seepage; C, C. denticulata Harmelin, n. sp., underside of pottery fragment, Cassis, Port-Miou, 18 m; D, C. gautieri Harmelin, n. sp., underside of Pinna shell, paratype MNHN-IB-2014-1921, Veyron, 24 m; E, C. macaronensis Harmelin, n. sp., underside of pebble, paratype MNHN-IB-2014-1926, Madeira, Porto Santo, Baixo Is.; F, C. fayalensis Harmelin, 1978, underside of pebble, Azores, Saô Miguel, Vila Franca, 15 m. Scale bars: 1 cm.