Cliona acephala, Zea, Sven & López-Victoria, Mateo, 2016

Zea, Sven & López-Victoria, Mateo, 2016, Cliona acephala (Porifera: Demospongiae: Clionaida), a new encrusting excavating reef sponge from the Colombian Caribbean belonging to the Cliona viridis species complex, Zootaxa 4178 (4), pp. 583-592 : 585-588

Cliona acephala n. sp.

Figures 1–4

Cliona sp. 2; Zea 1993: 87 (appendix; ecology).

Cliona n. sp.; Escobar et al. 2012, Fig. 1 G (molecular phylogeny)

Type material and type locality. Holotype: ICN-MHN(Po) 226, Bahía de Santa Marta, Punta de Betín (11°15’1” N, 74°13’13” W), completely covering a coral head, rocky shore, 4 m depth, coll. S. Zea, 20 March 1981 . Paratypes: USNM 32001 , Bahía Concha, east flank (11°18’04”N, 74°08’53”W), below Porites reef, 3-15 m depth, coll. K. Rützler, 18 July 1969 (collector number SM17, tentatively identified as?” Anthosigmella ” varians ) ; INV- POR 1263 , Bahía de Nenguange, Piedra Ahogada (11°19’42”N, 74° 4’50”W), on dead coral, reef, 9 m depth, coll. S. Zea, 17 March 1981 ; INV-POR 1264, Ensenada Granate, NE side (11°18’11”N, 74°11’43”W), on dead coral, reef, 12 m depth, coll. S. Zea, 25 Nov. 1981; INV-POR 1265, Bahía de Santa Marta, Morro, SW side (11°14’58” N, 74°13’49” W), on dead coral, reef, 15 m depth, coll. S. Zea, 26 Jan. 1988 (material of Zea 1993, identified as Cliona sp. 2); INV-POR 1266, same locality as holotype, on dead coral, reef, 11 m depth, coll. S. Zea, 26 June 2003 .

Diagnosis. Rounded to irregular encrustations, up to 2 mm thick, reaching about 50–80 cm in maximum diameter. Surface color amber brown to gray brown, oscular collars bright sulfur yellow, excavating tissue ochre yellow. Surface even to irregular, smooth. Oscules 1–8 mm in diameter when open, scattered and conspicuous, with a 1–2 mm tall, fleshy collar. Ectosomal, epilithic tissue leathery, choanosomal, endolithic tissue crumbly. Excavation up to 1–3 cm deep, filled with tissue. Megascleres tylostyles, mostly with narrow, often misshaped heads, or almost without heads, 280–480 x 5.8–17.5 µm (length x width). No spirasters present.

Description. Morphology. ( Figs. 1–2 ) Excavating sponge that completely encrusts the excavated substratum with a somewhat thick (up to 1–2 mm), rounded or irregular, epilithic tissue crust; size from a few centimeters up to about 50 to 80 cm in diameter. Surface color amber brown to gray brown, sometimes greenish; oscular collars bright sulfur yellow. Surface as even, or as rugose as the underlying substratum; smooth, rather velvety, shiny when not covered by sediment-cleaning mucus. Oscules conspicuous, scattered, 1–8 mm in diameter when open, with a 1–2 mm tall collar. Consistency of the ectosome leathery, crumbly for the choanosomal tissue. Sponge penetrates and excavates about 1–3 cm underneath the surface. Excavating tissue ochre yellow, fills calicular spaces and excavated chambers. Excavated chambers round, 140 µm–1,100 µm in diameter; conical chambers 550–2,150 µm wide and 250–2,500 µm deep underneath oscules. Ectosome dense, 400–730 µm thick, traversed by tree-like plumose erect tracts up to 8–10 spicules thick, separated at the base 200–300 µm, which ascend and divide 1–2 times up to the surface. Ectosome traversed by irregularly ascending canals 50–180 µm wide, apparently opening to surface pores. Choanosomal tissue less dense, traversed by 35–2,500 µm wide canals, and by ill-defined tracts of 2–3 spicules, more often located towards the walls. Chamber walls creased with concave erosion scars, up to 60 µm wide. The holotype had eggs 40–70 µm in diameter (collected March 1981).

Spicules. ( Figs. 3–4 ) Megascleres are tylostyles, slender, slightly curved, with a slightly visible central canal; some tylostyles lack a head, but for most the heads are narrow, elongated, more bulged on one side, often misshaped, some subterminal; tips long, acute, most often telescoped. Dimensions (length x width) 280–480 x 5.8– 17.5 µm; means of three specimens 340.2–424. 8 x 7.8–13.5 µm. Heads, when present, 6.9 – 10.3 µm wide and 8.1– 15.0 µm long. No microsclere spirasters present. (Spicule preparations of paratype INV-POR 1264 showed spirasters 13 – 30 µm long, with spires 2 – 3 µm wide, and 1–5 turns, but upon closer inspection of ground and polished histological sections, they were not located lining choanosomal canals as it is usual in other encrusting clionaids (e.g., Zea & Weil 2003), but in sealed pockets lining excavating walls; we assumed these were foreign as in the other studied specimens we did not find any spirasters in histological sections or in spicule mounts made after nitric acid digestion of previously decalcified fragments or after bleach digestion of calcified fragments in constant agitation.)

Distribution. So far known only from the Santa Marta area, Caribbean coast of Colombia. Not seen in extensive surveys in other areas of Colombia (see Zea 1987), including the San Andrés and Old Providence Archipelago in the SW Caribbean ( Zea, 1987; 2001). Also not seen in reefs of Almirante Bay, Bocas del Toro ( Panama), Carrie Bow Cay ( Belize), Discovery Bay ( Jamaica), and of several locations in the east coast of south Florida and the Bahamas ( Zea et al. 2014). Interestingly, whereas in many other Caribbean reefs there are other brown fully encrusting clionaids (e.g., C. caribbaea , C. tenuis ), at Santa Marta C. acephala n. sp. is the only species showing this encrusting morphotype.

Ecology. C. acephala n. sp. inhabits rocky shores (on coral heads) and coral reefs, from about 6 m to 15 m in depth (see also Zea 1993). It is not very common. It was found most of the time on old dead coral, and only a few times part of its edge was observed adjacent to live, smaller coral colonies, which had their bordering tissue unhealthy (see Fig. 1 C). Sponge individuals with circular deep blue necrotic spots (surrounded by yellow tissue) were observed on Nov. 2003 and June 2005; one was seen paling in Jan. 2011. These may account for patches devoid of tissue and colonized by turf algae and filled by sediment seen in several individuals.

Etymology. Adjective from the Latin prefix a —meaning without, and the Greek kephale —meaning head ( Brown 1956), for the narrow to absent tylostyle megasclere heads. Following Article 31.2 of the International Code for Zoological Nomenclature (http://www.iczn.org/, accessed on 13 March 2016) we are using feminine acephala assuming Cliona is feminine, as when erecting the genus Cliona, Grant (1826) used the name celata for the type species, which is the feminine inflection of the Latin adjective celatus —meaning hidden, concealed ( Brown 1956).

Figures

FIGURE 1. Underwater photographs of Cliona acephala n. sp. (A) Bahía de Santa Marta, Morro, 10 July 1987, 15 m. (B) Morro, 10 Jan 1994, 5 m. (C) Ensenada Granate, 12 m, 23 June 2005. (D) Bahía de Santa Marta, Punta de Betín, 25 June 2002, 12 m.

FIGURE 2. Spicules of Cliona acephala n. sp. (A) Tylostyles. (B) Enlargement of heads and tip. (C) SEM enlargement of heads and tip.

FIGURE 3. Ground and polished histological sections of the holotype of Cliona acephala n. sp. (A) portion of the ectosome and coral skeleton in an osculum showing sponge tissue with aquiferous canals and excavating chambers in the coral skeleton. (B) Enlargement of the ectosome showing ascending plumose spicule tracts. (C) Excavated chamber filled with tissue, spicules and eggs, and with with characteristic erosion scars on the walls.

FIGURE 4. Size of tylostyles (width by length) of three specimens of Cliona acephala n. sp. from Santa Marta compared to those of a specimen of C. orientalis (INV-POR 658) from Heron Island, Australia. Data represent specimen means ± 1 standard deviation of 25 tylostyles. Hol = holotype; Par = paratype.