Reteporella mediterranea Hass, 1948

Ramalho, Laís V., López-Fé, Carlos M. & Rueda, José Luis, 2018, Three species of Reteporella (Bryozoa: Cheilostomata) in a diapiric and mud volcano field of the Gulf of Cádiz, with the description of Reteporella victori n. sp, Zootaxa 4375 (1), pp. 90-104 : 92-94

Reteporella mediterranea Hass, 1948

( Fig. 2 ; Table 1)

Reteporella mediterranea Hass, 1948: 131 , figs 19–21, 24–25, 29, 39–40; plate V: 19, 24; plate VI: 27–28. Reteporella mediterranea: Gautier, 1962: 234 .

Reteporella mediterranea: Zabala, 1986: 543 .

Material examined. MNCN 25.03 /3986, Station DA-01, continental shelf diapiric field, 36º 21’18.19’’N – 6º 21’56.51’’W, 36º 21’12.82’’N – 6º 21’43.73’’W, 31 July 2013, benthic dredge, 36.6–43.6 m depth, R/V Ramón Margaleff , Cadhys 0713 expedition, Instituto Español de Oceanografia (IEO) coll . MNCN 25.03 /3987, Station DA-04, continental shelf diapiric field, 36º 20’32.81’’N – 6º 23’40.22’’W, 36º 20’30.77’’N – 6º 23’34.39’’W, 31 July 2013, benthic dredge, 46.6–48.9 m depth, R/V Ramón Margaleff , Cadhys 0713 expedition, IEO coll . MNCN 25.03 /3988, Station DA-05, Gazul MV, 36º 33’35’’N – 36º 33’29’’N, 6º 56’06’’W – 6º 56’08’’W, 22 June 2010, benthic dredge, 418–422 m depth, R/V Emma Bardán , Indemares-Chica 0610, IEO coll . MNCN 25.03 /3989, Station DA-08, continental shelf diapiric field, 36º 19’42.13’’N – 6º 21’15.80’’W, 36º 19’39.26’’N – 6º 21’07.72’’W, 31 July 2013, benthic dredge, 41.4–45.6 m depth, R/V Ramón Margaleff , Cadhys 0713 expedition, IEO coll . MNCN 25.03 /3990, Station DA-11, Gazul MV, 36º 33’42’’N – 36º 33’51’’N, 6º 56’19’’W – 6º 56’19’’W, 27 June 2010, benthic dredge, 461–462 m depth, R/V Emma Bardán , Indemares-Chica 0610, IEO coll . MNCN 25.03 /3991, Station DA-15, continental shelf diapiric field, 36º 19’42.13’’N – 6º 21’15.80’’W, 36º 18’21.47’’N – 6º 25’04.00’’W, 1 August 2013, benthic dredge, 52.1–56.3 m depth, R/V Ramón Margaleff , Cadhys 0713 expedition, IEO coll . MNCN 25.03 /3992, Station DA-18, continental shelf diapiric field, 36º 20’10.31’’N – 6º 22’31.36’’W, 36º 17’41.68’’N – 6º 22’31.57’’W, 1 August 2013, benthic dredge, 42.3–45.2 m depth, R/V Ramón Margaleff , Cadhys 0713 expedition, IEO coll.

Material used for SEM. MNCN 25.03/3997, Station DA-11, Gazul MV, 36º 33’42’’N–36º 33’51’’N, 6º 56’19’’W–6º 56’19’’W, 27 June 2010, benthic dredge, 461–462 m depth, R/V Emma Bardán, Indemares-Chica 0610, IEO coll.

Description. Colony erect, cup-shaped, 1.2–3.8 cm long by 0.7–4.7 cm wide, robust, erect part of the colony 1.5–2 mm thick, with a large and strongly calcified base ( Fig. 2A ). Fenestrulae small and oval ( Fig. 2B ). Autozooidal orifices in alternate order (3–5 in a transverse series); autozooids elongate, without distinct boundaries. The frontal wall is imperforate except for a few (4–7), small, rounded areolar pores ( Fig. 2B–C ). Primary orifice hidden by the short peristome, almost circular, distal region beaded with different levels of development ( Fig. 2D–E ); secondary orifice slightly wider than long with a pair of proximolateral spines and a small, rounded pseudospiramen at one side of the peristomial, suboral avicularium ( Fig. 2C–D ); some orifices are occluded by secondary calcification in the oldest parts of the colony ( Fig. 2C ). Suboral avicularium is slightly lateral and proximally directed, with complete crossbar, rounded rostrum and toothed border ( Fig. 2C–E ). Single or paired, triangular avicularia on the frontal of each zooid, variable in size, usually proximolaterally directed but sometimes laterally or proximodistally directed, rostrum smooth, slightly raised from the surface, palate with different shapes of the opening (rounded, D-shaped or trifoliate); crossbar complete ( Fig. 2C–D ). Ooecium longer than wide, immersed in the frontal wall; median fissure across the frontal surface almost reaching the labellum. Dorsal side with small, rounded pores and triangular avicularia similar to those on the frontal, more frequently placed near the sutures and fenestrulae ( Fig. 2F ).

Remarks. So far, fifteen species of Reteporella have been recorded around the Iberian Peninsula, from the Mediterranean Sea to the North Atlantic Ocean ( Gautier 1962; Zabala & Maluquer 1988; Reverter-Gil & Fernandez-Pulpeiro 2001; Reverter-Gil et al. 2014). Similarly to R. mediterranea , Reteporella beaniana ( King, 1846) has a rounded suboral avicularium but differs in having 3–5 large marginal pores, frontal avicularia with a proximal edge developing a bifid mucro projecting above the orifice, and an open pseudosinus without a labial pore. Reteporella watersi ( Nordgaard, 1907) shares with R. mediterranea rounded and toothed suboral avicularia, small peristomial and labial pores, and two oral spines. However, the former species has a finely or coarsely rugose frontal and dorsal surface, and frontal avicularia similar to suboral avicularia on the frontal and dorsal sides.

Reteporella mediterranea as described by Hass (1948) is similar to the material collected in the Gulf of Cádiz. These features include a pair of oral spines, suboral avicularium with serrate rostrum similar in size (50 µm long), frontal and abfrontal avicularia with the same shape (oval and triangular) and similar in size. The colonies described by Gautier (1962), Zabala (1986) and Zabala & Maluquer (1988) are similar to the material from Cádiz in the number of oral spines, shape, and size of frontal and abfrontal triangular avicularia. However, they differ in the average size of suboral avicularia (30 µm long). Recently, Madurell et al. (2013) described R. mediterranea from material collected at Cap de Creus (Gulf of Lion, NW Mediterranean, 225 m depth). Their material was similar to the specimens from Cádiz, but the suboral avicularium showed variable length (34–51 µm, mean 43 µm). Nevertheless, the size variability of the suboral avicularium may not be relevant to differentiate the specimens collected in the Mediterranean from those collected in the Gulf of Cádiz. Thus, we believe that the latter material belongs to R. mediterranea . This study provides the first record of R. mediterranea from the Atlantic Ocean.

Distribution. Mediterranean Sea ( Hass 1948), Gulf of Cádiz (continental shelf diapiric field and Gazul MV; present study). The colonies of R. mediterranea collected in the continental shelf diapiric field of the Gulf of Cádiz occur on hard bottoms with a well-formed coralligenous habitat dominated by gorgonians (e.g. Paramuricea clavata, Eunicella verrucosa), scleractinians (e.g. Dendrophyllia ramea, Coenocyathus anthophyllites), bryozoans (mainly Myriapora truncata and Pentapora fascialis ), and sponges ( Axinella spp.). The specimens collected in the Gazul MV occur on authigenic carbonate bottoms with cold-water coral banks, mainly Madrepora oculata colonies, anthipatharians ( Anthipathella, Leiopathes ), and sponges ( Petrosia , Haliclona ), as well as on aggregations with the hexactinellid sponge Asconema setubalense .

Figures

FIGURE 2. Reteporella mediterranea Hass, 1948.A, MNCN 25.03/3987, general view of an erect and cup-shaped colony.B– F, MNCN 25.03/3997. B, general view of part of the colony, showing fenestrulae and autozooids; C, group of autozooids and avicularia; D, close-up of the secondary orifice with suboral avicularia, oral spines and triangular avicularia; E, close-up of two primaryorifices with beadedanter; F, dorsal view showinga fenestrula,pores and triangular avicularia.Scalebars:A, 3mm;B, 500 µm; C, F, 200 µm; D, 100 µm; E, 50 µm.