Reteporella pelecanus López de la Cuadra & García-Gómez, 2001

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 : 95-98

Reteporella pelecanus López de la Cuadra & García-Gómez, 2001

( Figs 3 , 4 ; Table 2)

Reteporella pelecanus López de la Cuadra & García-Gómez, 2001: 1727 , fig. 4.

Material examined. 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 /3993, Station BT-10, Tarsis MV, 21 February 2011, beam-trawl, 610–625 m depth, R/V Cornide de Saavedra , Indemares-Chica 0211, IEO coll. ; MNCN 25.03 /3994, Station BT-03, Tarsis MV, 18 February 2011, beam-trawl, 585–652 m depth, R/V Cornide de Saavedra , Indemares-Chica 0211, IEO coll. ; MNCN 25.03 /3995, Station BT-16, Pipoca MV, 22 February 2011, beam-trawl, 596–675 m depth, R/V Cornide de Saavedra , Indemares-Chica 0211, IEO coll.

Material used for SEM. MNCN 25.03 /3998, Station BT-16, Pipoca MV, 22 February 2011, beam-trawl, 596– 675 m depth, R/ V Cornide de Saavedra, Indemares-Chica 0211, IEO coll. ; MNCN 25.03 /3999, 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 /4000, Station BT-03, Tarsis MV, 18 February 2011, beam-trawl, 585–652 m depth, R/ V Cornide de Saavedra, Indemares-Chica 0211, IEO coll. ; MNCN 25.03/3566. FAUNA IV expedition st. 283, 39º 53.09’ N, 0º 36.80’ E, Columbretes Islands ( northwestern Mediterranean ), 80 m depth, July 1996 (part of the material of the original description in López de la Cuadra & García Gómez 2001).

Description. Colony fan-shaped, variable in size, 0.7–2.5 cm long by 0.7–2.4 cm wide, delicate and with large fenestrulae ( Fig. 3A ). Autozooids arranged alternately in series of two, longer than wide ( Figs 3B , 4C ), delimited by deep sutures that disappear with secondary calcification, frontal surface smooth with 4–7 small, rounded areolar pores ( Figs 3B , 4C ). Primary orifice hidden by peristome, semicircular, as long as wide with a pair of small triangular condyles at the proximal corners ( Fig. 3D ); anter denticulate, denticles sometimes partially hidden by the outer rim, more developed than in other species of the genus ( Figs 3D , 4A–B ). This, together with the development of the peristome, makes the denticulation challenging to see from outside ( Fig. 3D ). The difficulty of observing the denticulation inside the orifice is apparent in both the present material and in that from the north-western Mediterranean. One pair of delicate peristomial spines frequently broken off; circular pseudospiramen located near the peristomial edge, located medially when a peristomial avicularium is absent and displaced laterally if the avicularium is present ( Fig. 3B–C ). Four kinds of avicularia present: (1) suboral avicularium, large, with a robust and hooked rostrum, almost perpendicularly raised from the surface, with a complete crossbar ( Figs 3B–C , 4C ); (2) frontal avicularium, single or paired, often located along the margins of the autozooids, proximally directed, either outwards or medially, shoe-shaped with rounded rostrum, complete crossbar and palatal foramen approximately half the length of the rostrum, border sometimes slightly raised ( Figs 3B , 4C ); (3) large dorsal avicularium at the proximal border of most of the fenestrulae ( Fig. 4D ), elongate and laterally directed, with a slender spatulate rostrum, slightly hooked at its end, and palatal foramen half the length of the rostrum; (4) small, dorsal, oval avicularium similar in shape and size to the frontal ones but randomly directed, usually located near the edge ( Fig. 4D ). Ooecium hyperstomial, slightly longer than wide, proximal border almost straight, without labellum; a long fissure along most of the midline ( Figs 3B–C , 4D ). Dorsal side with conspicuous sutures and small pseudopores, usually located near the sutures and around the avicularia ( Fig. 4D ).

Remarks. This species is easily distinguished by the large dorsal avicularia, elongate and disposed almost perpendicular to the growth axis of the colony, and by the large and hooked suboral avicularium. The most similar species, Reteporella grimaldii ( Jullien, 1903) is characterized by three types of frontal avicularia: (1) 1–2 oval avicularia on each zooid (frequent); (2) triangular avicularia with an acute rostrum (rare); (3) large, robust and triangular avicularia with a hooked rostrum, not associated with the peristome. Furthermore, R. grimaldii differs in having elongate, triangular dorsal avicularia with a hooked rostrum. Reteporella pelecanus , described by López de la Cuadra & García-Gómez (2001) from the Mediterranean, has a longer ooecium (250 µm long) and longer suboral avicularia (160 µm long) than the specimens from Cádiz. However, the size of the zooids (550 µm long by 230 µm wide), small and rounded avicularia (90 µm long), and dorsal avicularia (400 µm long) is similar. The frontal avicularia in our material are frequently placed more laterally than centrally, compared to the original description, but this may be considered as an intraspecific variation. Reteporella pelecanus was originally recorded near the Balearic Islands (Mediterranean Sea) at 80–120 m depth (López de la Cuadra & García-Gómez 2001), and the difference in size could be influenced by abiotic factors, mainly temperature and depth. Thus, we conclude that these differences are not enough to erect a new species, and the specimens here described are assigned to R. pelecanus .

The presence of R. pelecanus at three MVs (Gazul, Tarsis, and Pipoca) of the shallow field of the fluid expulsion of the Gulf of Cádiz represents the first record of this species in the Atlantic, at a considerable higher depth than the previously published records (López de la Cuadra & García-Gómez 2001).

Distribution. The Mediterranean Sea, near the Mahón Island (Baleares Island) (López de la Cuadra & García- Gómez 2001); Gulf of Cádiz (Gazul, Tarsis, and Pipoca MVs) (present study). The colonies from Cádiz were collected from different sea bottoms. At the Gazul MV, the sea bottom is characterized by abundant authigenic carbonates, harboring cold-water coral banks and sponge aggregations. At Tarsis and Pipoca MVs, mixed sea bottoms present sparse authigenic carbonates with small gorgonians ( Swiftia ), while soft bottoms are colonized by sea pens ( Kophobelemnon, Pennatula ), scleractinians ( Flabellum ), and echinoids ( Cidaris cidaris ).

Figures

FIGURE 3. Reteporella pelecanus López de la Cuadra & García-Gómez, 2001. A, MNCN 25.03/3993, general view of a colony encrusting a polychaete tube. B–D, MNCN 25.03/3998. B, general view of a colony fragment showing fenestrulae and fertile autozooids; C, close-up of an autozooid with suboral, triangular avicularium and ooecium; D, detail of the primary orifice with distal external rim hiding the beaded anter and a pair of triangular condyles. Scale bars: A, 3 mm; B, 300 µm; C, 100 µm; D, 500 µm.

FIGURE4. Reteporella pelecanus López de la Cuadra & García-Gómez, 2001. A–B, MNCN 25.03/3566. A, inner view of the primary orifice showing the beaded anter; B, detail of the primary orifice showing the very developed outer rim, which may hide the denticles in frontal view. C–D, MNCN 25.03/3998. C, fertile zooids with suboral and frontal, shoe-shaped avicularia; D, dorsal side of the colony showing fenestrulae, elongate and shoe-shaped avicularia. Scale bars:A–B, 20 µm; C, 100 µm; D, 500 µm.