Collarina fayalensis Harmelin, 1978

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 : 393-394

Collarina fayalensis Harmelin, 1978

( Figs 5 ; 7B ; 15B ; 17D ; 18F ; Tables 1-3 )

Collarina fayalensis Harmelin, 1978a: 190 , fig. 9. — Arístegui 1984 (in part): 230, pl. 11, fig. 7 (not fig. 6).

TYPE MATERIAL. — Holotype and paratypes. Azores, Faial Is., Castelo Branco, R/ V Jean-Charcot, BIAÇORES 1971 St. P. 11, 38°31’12”N,

28°42’7”W, 5-7 m, 12.X.1971, H. Zibrowius leg., 12 small colonies on pebble together with colonies of C. macaronensis Harmelin , n. sp. (recorded as C. balzaci: Harmelin 1978a ), MNHN-IB- 2008-7909.

OTHER MATERIAL EXAMINED. — Azores archipelago. Formigas Is., R/V Jean-Charcot, BIAÇORES 1971 St. P. 43, 37°16’14”N, 24°46’54”W, 15 m, 7.XI.1971, H. Zibrowius leg., 1 small colony on pebble, MNHN . — São Miguel Is., Ilhéu de Vila Franca do Campo , Azores Bio-Oceanographic Survey 1979, ABOS St. AC- 79.6, 37°42’20”N, 25°26’33”W, 15 m, 24.VII.1979, coll. by JGH, c. 30 colonies on 7 pebbles, 5 colonies on broken Pinna shell, MNHN, NHMUK . — São Miguel Is., Ponta da Galera , ABOS St. AC-79.7, 37°42’25”N, 25°30’32”W, 14 m, 24.VII.1079, coll. by JGH, 3 colonies on 2 small pebbles in submarine cave; 3 colonies on Pinna shell, MNHN, NHMUK . — São Miguel Is., Capelas , ABOS St. AC-79.9, 37°50’37”N, 35°41’19”W, 15 m, 25.VII.1979, coll. by JGH, 6 colonies on 1 pebble, MNHN . — São Jorge Is., Ponta da Rosais , ABOS St. AC-79. 29, 38°45’06”N, 28°18’59”W, 20 -22 m, 6.VIII.1979, coll. by H. Zibrowius, 1 colony on pebble, MNHN . — Graciosa Is., Ilhéu da Praia , ABOS St. AC-33, 39°03’36”N, 27°57’11”W, 20 m, 8.VIII.1979, coll. by JGH, 1 ovicelled colony on pebble from a tunnel, MNHN .

DIAGNOSIS. — Colonies small to large; autozooids longer than broad, with very extensive gymnocyst and minute costate shield, formed by 2-5 very short costae with smooth surface and a large marginal pelma; presence of large pseudopores on the gymnocyst; apertural bar poorly prominent and pierced by large pelmata; orifice longer than broad with proximal edge slightly concave, 2-5 thin oral spines; adventitious avicularia paired, directed disto-laterally; ooecium kenozooidal bearing a distal avicularium; ancestrula with 5 or 6 spines.

DESCRIPTION

Colony encrusting, pluriserial, unilaminar, small- to large-sized (> 1000 autozooids). Autozooids longer than broad, roughly pentagonal with shorter distal side bearing the oral spines. Gymnocyst occupying the largest part of the frontal surface, moderately convex, punctured by several large gymnocystal pseudopores at the zooid margin or occasionally nearer to the costate shield ( Fig. 5B, D, E ). Costate shield very small, with only 3-4 costae in most cases (range 2-5), with smooth surface and poorly demarcated basal, ascending part, the latter bearing a large pelma and generally with a second smaller pore near the centre of the shield; intercostal lacunae generally limited to a single, very small one per pair, centrally located and a much larger, semi-rectangular “basal intercostal space” with a tiny median slot ( Fig. 5G ). Apertural bar low, with a slightly prominent centre, pierced by four pseudopores, two medium-sized on either side of the midline and two larger lateral pores, close to and below the base of the avicularia ( Figs 5B, C, F ; 7B ). Adventitious avicularia paired in most cases (> 95%), directed laterally with a slight distal angle ( Figs 5A, B, D, F ; 14C ), nested cystids occasionally present ( Fig. 17D ). Orifice longer than broad ( Table 1 ), proximal edge slightly concave and often irregularly indented, with a small knob at each corner; condyles small ( Figs 5B, F ; 7B ). Oral spines with relatively narrow base, 2-5 in non-ovicelled zooids, 3 in majority (75%), 2 relatively thin in ovicelled zooids ( Fig. 5C ). Ovicell present in large colonies, less frequently in medium-sized ones, bearing a distal avicularium in most cases (> 80%); ooecium kenozooidal, formed at the colony edge, with surface pierced by about 12-15 medium- sized pseudopores, orifice about 40% larger on average than that of a non-ovicelled zooid, a distal avicularium in most cases ( Figs 5C ; 15B ). Ancestrula similar to older zooids but smaller, 3 very small costae, 6 spines, orifice longer than broad.

DISTINCTIVE FEATURES

Collarina fayalensis is easily identified by the minute size of the costate shield, formed by 2-4 very short costae, which contrasts with the huge development of the gymnocyst. The greater number of costae (4-6) noted by Harmelin (1978a) included the pair forming the apertural bar. The latter is typically poorly prominent and pierced by large pelmata. The presence of large pseudopores on the gymnocyst is also a peculiar feature, shared with C. macaronensis Harmelin , n. sp., in which these marginal pseudopores are less numerous. The Azorean material examined here, much more abundant than the one (small colonies on a single pebble) of the type-series ( Harmelin 1978a, herewith Fig. 5E ), showed that this species can develop large colonies and provided information on the ovicell and the habitat. Ovicells were not frequent, present only in relatively large colonies. This feature may indicate that C. fayalensis is not able to develop fertile colonies on ephemeral substrates, in contrast to C. balzaci .

HABITAT AND GEOGRAPHICAL DISTRIBUTION

Most sampled specimens, including the types, encrusted pebbles and cobbles at shallow depth ( Fig. 18F ). On the other hand, few colonies were found on empty shells of Pinna rudis Linnaeus, 1758 from the same sites which, otherwise, were colonized by many other bryozoans. Therefore, pebbles can be considered the typical habitat of C. fayalensis . These pebbles and cobbles were of volcanic origin, with a smooth surface, small- to medium-sized (up to 15 cm, but sample constraints may have limited this maximum size), and densely colonized on all faces by various species of bryozoans and secondarily by serpulids. This type of colonization, equally distributed all around the subspherical substrates, indicates that the sampling sites were washed by active water circulation limiting sedimentation. The most frequent bryozoans in the assemblage including C. fayalensis were Microporella sp., Schizoporella sp., Chorizopora brongniartii ( Audouin, 1826) and Disporella sp. All examined specimens of C. fayalensis came from various localities of five Azores isles: Faial, São Miguel, Formigas, São Jorge, Graciosa. This species has also been recorded in the Canaries Islands by Arístegui (1984), but his figures indicate that C. fayalensis co-occurs with C. macaronensis Harmelin , n. sp. in the Canaries (see below).

Figures

FIG. 5. — Collarina fayalensis Harmelin, 1978: A-C, non-ovicelled and ovicelled autozooids showing the structure and limited extent of the costate shield, orifice dimorphism, small spines and relatively narrow avicularia; D, non-ovicelled zooid, for marginal pores; E, drawing from Harmelin (1978: fig. 9); F, distal part of a non-ovicelled zooid from a colony edge; G, proximal half of costate shield, note the distribution of pelmata and the shape of the basal intercostal spaces. Origin: Azores - Saô Miguel, Vila Franca Is., 15 m (A-C, F, G); Formigas Is., 15 m, ‘Jean Charcot’ Biaçores 1971, P.43 (D); Faial, ‘Jean Charcot’ Biaçores 1971, P.11 (E). Scale bars: A, 200 µm; B-D, 100 µm, F, 50 µm; G, 25 µm.

FIG. 7. — Outlines of orifice,apertural bar,avicularium and portion of costate shield and gymnocyst:A, Collarina balzaci (Audouin,1826);B, C. fayalensis Harmelin, 1978, C, C. denticulata Harmelin, n. sp. Scale bar: 100 µm (orifices), 50 µm (avicularia).

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.

FIG. 14. — Collarina sp.: A, colony growing edge; B, non-ovicelled zooid; C, orifice, note the particular shape of the proximal edge (poster) and the structure of the apertural bar with two laterally directed avicularia; D, ancestrula and zone of astogenetic change. Origin: MNHN-IB-2014-1928, Corsica, Île-Rousse, 5 m. Scale bars: A, D, 200 µm; B, 100 µm; C, 50 µm.