Agelas clathrodes Schmidt 1870

Agelas clathrodes (Schmidt, 1870)

Figs. 1 B, 11, 15D

Etymology from Greek, meaning lattice, grate.

Chalinopsis clathrodes Schmidt, 1870: 60; Topsent 1920a: 22.

Ectyon flabelliformis Carter, 1883: 311, pl. 11, Fig. 1, la (in part: paralectotype only BMNH 1884.4.14.4).

Ectyon sparsus Gray sensu Carter 1882a: 281 (Antigua. Two hypotypes mentioned, five present: CLM Sp. 24, registered BMNH 39.3.24.45; Sp. 23, 26, both registered BMNH 39.3.24.57; Sp. 25, registered BMNH 39.3.24.58; Sp. 30, not registered); Carter 1883: 312 (in part: only BMNH 1842.12.21.40, with Carter's 'No. 462', West Indies, ex Bowerbank collection).

Agelas clathrodes; Wiedenmayer 1977: 131 (in part, Figs. 139C–D, pl. 28 Fig. 12; USNM 30218, USNM 30129, 0719); Collette & Rützler 1977: 309; Bakus & Thun 1979: 418; George & George 1979: 45; Colin 1978: 86, Fig. pg. 60; van Soest 1981: 32; Gómez-López & Green 1984: 81, Figs. 21–22; Wintermann-Kilian & Kilian 1984: 132; Pulitzer-Finali 1986: 110, Fig. 32; Zea 1987: 217, Fig 79, Pl. 3, Figs. 3–4; van Soest & Stentoft 1988: 98, Fig. 47; Humann 1992: 52, Figs. P. 52, 53; Gammill 1997: 7, Figs. 8, 20, 26, 31, 34, 94; Lehnert & van Soest 1996: 63, Fig. 53; Lehnert & van Soest 1998: 81, Lehnert & van Soest 1999: 154; Assmann 2000: 37, pl. 5, Figs. B–E; Valderrama 2001: 48; Gómez 2002: 74; Alcolado 2002: 61; Díaz 2005: 470; Collin et al. 2005: 650; Erpenbeck et al. 2007: 1564; Muricy et al. 2008: 890, figs.; 2001: 37; Rützler et al. 2009: 302; Zea et al. 2009; Messing et al. 2009; Moraes 2011: 164, figs.

[Non: Agelas clathrodes; Wiedenmayer 1977: 131 (in part) B279–280 (= A. sventres); van Soest 1981: 10 (= A. citrina); Álvarez & Díaz 1985: 90, Fig. 26 (= A. citrina); Hoppe 1988: 120, Fig. 2 C. as A. clathrodes 'flabelliform' (= A. citrina); Kobluk & van Soest 1989: 1210 (= A. citrina); Erhardt & Moosleitner 1997: 80 (= A.sventres)].

? Agelas rudis Duchassaing & Michelotti, 1864: 76, pl. 15, Fig. 2, St. Thomas, no type material is extant (see van Soest et al. 1983: 197).

Material and distribution. Holotype examined, deposited in the Zoologisk Museum København; it was collected off Caracas without any further information. The material reviewed here includes (but is not restricted to) specimens from the Bahamas (INV– POR 934), Belize (INV– POR 960), Rosario Islands (INV– POR 968, see also Zea, 1987), Jamaica (INV– POR 996), San Andres Island (INV– POR 982, see also Zea, 1987 from Old Providence) and Santa Marta (INV– POR 991, see also by Wintermann-Kilian and Kilian, 1984).

All specimens collected in reefs of Curaçao and Barbados were provisionally labelled A.? clathrodes or A.? citrina, but later they were identified as A. citrina. Although A. clathrodes may be absent from shallow locations of Barbados, van Soest & Stentoft (1988) collected two specimens from 108–135 m; those specimens (ZMA – POR 5355, 5356) were examined by us and clearly belong to A. clathrodes; other specimens present at ZMA include Los Roques (Venezuela, ZMA – POR 5325) and the U.S. Virgin Islands (ZMA – POR 8551); previous works (including accounts by Wiedenmayer 1977 and Zea 1987) have reported the species also from Florida East coast and the Bahamas (Gammill 1997; Assmann 2000; Rützler et al. 2009; Zea et al. 2009; Messing et al. 2009); Cuba (Alcolado 2002), Dominican Republic, U.S. Virgin Islands, Puerto Rico (Pulitzer-Finali 1986; Weil 2006), Gulf of Urabá in Colombia (Valderrama 2001), Panama (Díaz 2005; Collin et al. 2005), Yucatán, Campeche and Veracruz in the Gulf of Mexico (Gómez López & Green 1984; Gómez 2002; Rützler et al. 2009;), and several areas of continental Brazil (from N to SE regions, Muricy et al. 2008; 2011) and its oceanic islands (Atol das Rocas, Fernando de Noronha, cf. Moraes 2011); from the above, we consider A clathrodes a tropical western Atlantic species (see also Gammill 1997). Our specimens were found from 7 to 38 m in depth, abundant at 23– 30 m.

Description. The shape of this species can be flabellated (Fig 11 B), fan-shaped (with a narrow base) or, commonly, it can have an ear-like shape (Fig 11 D) with rounded or lobate margins, sometimes converging to vase shape (Fig 11 E). When juvenile, specimens tend to fill crevices (Fig 11 C, 11F) or to be lobate (Fig 11 A). Erect specimens are 10–60 cm tall by 15–100 cm wide and 6–30 cm thick; several enormous ear-like specimens observed at Rosario Islands easily surpassed 1 m in diameter, and we observed a few of about 2–3 m (Fig 11 E). The external colour varies from bright scarlet to orange; internal colour spectrum orange, orange yellow or tan; sometimes the channels or unexposed areas have a lighter colour. Pinacoderm rests on tracts of spicules protruding from main fibres; sometimes channels, oscules or dense walls from the skeleton are visible under the pinacoderm. Numerous openings with different shapes: circular 1–10 mm, elongated (key hole-like) 2–4 cm; here and there, several elongated openings could join together in a large aperture 3–8 cm wide. On the side opposite to the main current flow, the openings usually are covered by a pinacoderm, sometimes transparent, or otherwise white or slightly coloured. Its consistency is toughly compressible but flexible in life, a little harder when dry or preserved. Choanosome is very cavernous, lined by a bright endopinacoderm; walls (0.2–3 cm) are dense and firm. Caverns and internal channels are not very wide (0.4–2 cm), strongly interconnected between them and to the openings.

Reticulate skeleton with cored (0–6) an echinated primary fibres, 40–105 µm in diameter; secondary and tertiary fibres 20–75 µm in diameter, also echinated but less than primaries. The acanthostyles have mostly 4 spines (sometimes 3–8) per whorl, are more or less uniform in size, straight, and shorter than any other Agelas species; length 55–248 (113±38.9) µm, width 2–17 (8±2.9) µm and 4–23 (10±2.9) whorls per spicule. Detailed lengths, widths and average number of whorls are shown in Table 2.

Remarks. Based on the form, size of spicules, diameter of the fibres and spicule architecture, we assign Pulitzer-Finali’s (1986) Agelas sp3 to A. clathrodes.

This species is commoner in deeper reef zones than in shallow ones. It is more frequent in Rosario Islands and Santa Marta, than in San Andrés Island, Jamaica, the Bahamas and Belize. Although there are confirmed records of A. clathrodes for SE Caribbean reefs (Curaçao, Venezuela, Barbados), it appears to be quite scarce there, where it has been confused with flabellated Agelas citrina (cf. Álvarez & Díaz 1985).

Gigantic growth forms were found in Rosario Islands (Fig. 11 E), not only for this species but also for many other sponges, on the southern shelf slope with a high input of suspended organic matter. When large and flabellated, this species is distinguished from flabellated A. citrina by the thicker and more slack and curled pinacoderm of the latter; when both are orange, the color of A. citrina is milkier. See A. citrina remarks.

When smaller, A. clathrodes can be easily confused with A. sventres, especially with the football-shaped or crevice-filling specimens of the former. In the field, lobed or rounded specimens of A. sventres are distinguished by having scattered round oscules with a collar-like membrane, which are altogether absent in A. clathrodes. The distinguishing feature of A. clathrodes is the shorter spicules with complete and regular rows of spines; this character could be used with some confidence to separate this species from other bright orange Agelas such as A. citrina (longer spicules), A. schmidti and A. sventres (both with slightly longer spicules with incomplete irregular rows of spines).