Agelas sventres Lehnert

Parra-Velandia, Fernando J., Zea, Sven & Van Soest, Rob W. M., 2014, Reef sponges of the genus Agelas (Porifera: Demospongiae) from the Greater Caribbean, Zootaxa 3794 (3), pp. 301-343 : 334-337

Agelas sventres Lehnert & van Soest, 1996

Fig. 14

Species named to follow up the working name Agelas sp. 3 used by Sven Zea to refer to this species (from the Spanish word “tres” for the number three).

Agelas sventres Lehnert & van Soest, 1996: 65, Figs. 6, 22, 55; Lehnert & van Soest 1998: 81; Lehnert & van Soest 1999: 156; Assmann et al. 2001: 1594, supporting info p. 1.; Muricy et al. 2008: 85, figs.; 2011: 40; Zea et al. 2009.

[Non: Agelas sventres ; Valderrama 2001: 51, Fig. 17 (= A. schmidti Wilson, 1902 )].

Agelas clathrodes ; Wiedenmayer 1977: 131 (in part, only Fig. 39A, B, specimens B279–80, fide Zea, 1987: 217); Erhardt & Moosleitner 1995: 80.

[Non: Agelas clathrodes ( Schmidt, 1870: 60) (a valid species)].

Agelas dispar ; van Soest 1981: 10, 34; Álvarez & Díaz 1985: 81, Fig. 23; Green et al. 1986: 130, Figs. 5 –6; Kobluk & van Soest 1989: 1216; Assmann 2000: pl. 6 (in part, orange morphotype only, Figs. A and D; Figs. B and C are A. dispar ).

? Agelas dispar ; Wintermann-Kilian & Kilian 1984: 132.

[Non: Agelas dispar Duchassaing & Michelotti, 1861: 76 (a valid species)].

? Agelas sparsus ; Green 1977: 92, Fig. 12 .

Unidentified demosponge; Colin 1978, Fig. page 101 top.

Agelas schmidti ; Alcolado 2002: 61 (in part, suggested synonymy).

[Non: Agelas schmidti Wilson, 1902: 398 (a valid species)].

Material and distribution. Holotype examined, deposited in the Zoölogisch Museum Amsterdam ( ZMA – POR 11322), collected at Jamaica, Discovery Bay, LTS, 51.8 m in depth. Material examined here includes specimens from (but is not restricted to) the Bahamas (INV– POR 932), Barbados (INV– POR 911, 917), Curaçao (INV– POR 901, 907, 910), Venezuela (Morrocoy, INV– POR 1196), Jamaica (INV– POR 1000, 1011) and San Andrés Island (INV– POR 986).

We prefer to assign our material from the continental coast of Colombia (including the one mentioned by Zea 1987 from Santa Marta and Valderrama 2001 from Urabá) to A. schmidti in account of their morphology and colour (see remarks). Other authors recorded the species from the Bahamas ( Wiedenmayer 1977; Assmann 2000; Zea et al. 2009), Cuba ( Alcolado 2002), Jamaica ( Colin 1978; Lehnert & van Soest 1998; 1999), Los Roques, Venezuela ( Álvarez & Díaz 1985), Bonaire (Kobluk & van Soest 1989), Curaçao (van Soest 1981; Zea et al. 2009), Veracruz, Gulf of México ( Green et al. 1986), and NE Brazil ( Muricy et al. 2008; 2011). From this information we conclude that this species has a tropical western Atlantic distribution, despite its absence in the north coast of Colombia (see remarks). Our specimens were found from 5 to 35 m in depth, abundant at 15– 20 m.

Description. It has a bulbous, massive-lobate ( Fig 14 C) to ball form ( Fig 14 B, 14D); 30–60 cm long axis and 10–40 cm short axis; balls 10–40 cm in diameter. In some of our studied areas ( The Bahamas, Venezuela, Curaçao) balls predominate, although they can elongate, while in others ( Jamaica, San Andrés Island) individuals may be irregular and multilobate. Lobes or balls may initially fill crevices ( Fig 14 A), with extensions inside the substratum that may come out separately; sometimes ( Jamaica), lobes grow as thick cylinders, erect or repent, often with fouled walls, crown by clean lobes. External colour orange, internal colour orange to orange yellow; when dry the external colour becomes light brown and the internal yellowish. Pinacoderm supported by tufts of spicules protruding from main fibres.

Surface smooth with many scattered apertures (2–10 mm); similar holes are visible under the pinacoderm but they do not open to the exterior; in grown specimens the apertures join together to form keyhole-like elongate openings 1–3 cm long, sometimes penetrating and crossing throughout the entire body. Large lobes and balls have characteristic oscules collared by a transparent milky membrane, elevated 2–3 mm from the pinacoderm. Consistency of grown lobes or balls is spongy, difficult to tear or cut, rather hard when dry; smaller lobes much softer. Choanosome extremely cavernous but caverns are usually similarly sized; the channels are (0.5–3 cm) lined by endopinacoderm. External walls thick 5–8 mm; internal walls thinner 3–6 mm.

Primary fibres are 50–90 Μm in diameter, cored (5–8 spicules per cross section) and echinated. Secondary and tertiary fibres are not cored and scarcely echinated, with diameters of 10–60 Μm. Along the acanthostyles, remarkably, verticils become undefined at the intermediate length, spines being acute in the beginning and the end of the spicule and blunt or absent in the middle. Also, in the middle portion verticills tend to have only one or two spines. The acanthostyles are straight to slightly curved, whorls of 4–7 spines (more often 4 when whorls are complete); length 75–284 (126±36.1) µm, width 4–13 (9±2.5) µm and 5–14 (9±1.4) whorls per spicule. Detailed lengths, widths and average number of whorls are shown in Table 2.

Remarks. Under this species we have now combined two different morphotypes, viz. bright orange ball sponges, previously called Agelas dispar by van Soest (1981) and others, dubbed as “the orange football sponge”; with bright orange crevice-filling lobate sponges, previously put into A. clathrodes by Wiedenmayer (1977), or as a then-undescribed form by Zea (1987), who used Agelas sp. 3 as a working name. The latter was subsequently named A. sventres by Lehnert & van Soest (1996). The concept of these two forms being different species apparently originally arose from the geographic predominance of one or the other morphotype. The finding of intermediate forms in Jamaica and part of the Bahamas led us to examine further the overall variation in form and microscopical characters. From the spicule architecture (e.g., paucity of spines in part of the spicule whorls), overall cavernosity, and formation of round lobes (which conformed the “football”), we decided that they all belonged to a single species.

Zea (1987) found several specimens of this species within Wiedenmayer´s (1977) A. clathrodes . Hence, some of the A. clathrodes and orange A. dispar records need to be re-examined. For example, massive orange specimens described as Agelas sparsus by Green (1977) from Veracruz in the Gulf of México could belong either to this species or to A. clathrodes .

Agelas sventres could be easily confused with small, crevice-filling and multilobate specimens of A. schmidti . Indeed, Alcolado (2002) considers that these two species are synonymous. We are still doubtful of their distinctiveness as separate species, but here decided to keep A. sventres as a good species, and place under A. schmidti the thin, creeping, continuously hollow branches ending up in tubes or slightly lobed and fluffy fingers (conforming to the holotype), often found inhabiting among rubble or below corals. In A. schmidti there are also crevice-filling specimens and large fouled cylinders crowned by clean, fluffy lobes. Creeping and crevice-filling cavernous specimens of A. sventres do not form a continuous cavity, and end up in larger, tougher lobes, rarely in tubes.

Remarkably, this red orange A. sventres – A schmidti pairing of morphotypes parallels the pairing of brown species-morphotypes A. dispar – A. wiedenmayeri , although species distinction is almost always clearer and easy in the latter pair. Both species of each colour pair came together on molecular analyses ( Parra-Velandia 2011). Perhaps speciation occurred or is occurring through habitat specialization (solid vs. cavernous substratum), in parallel in the two clades. Previously, some authors relied on form rather than on colour to distinguish species, putting together lobate brown A. dispar and A. sventres (as orange A. dispar ), brown A. wiedenmayeri (as A. schmidti ) and orange A. schmidti .

Figures

FIGURE 5. Photographs of Agelas sceptrum. Note the oscules position with respect to the growing axis. A) The Bahamas. B) Barbados; dark spots correspond to zoanthids. C) Erect specimen from Belize. D) Erect and exposed specimen from Curaçao. E) Branched erect specimen, Jamaica; note the branch tip attachment. F) Minute erect specimen from San Andres Island, Colombia.

FIGURE 12. Photographs of Agelas schmidti. A) Small round, tapered finger from Belize. B) Minute open tubes from Rosario Islands, Colombia. C) Fouled finger, the Bahamas (center only). D and E) Holotype at USNM (courtesy of K. Ruetzler and C. Dietrich).

FIGURE 14. Photographs of Agelas sventres. A) Two small masses, the Bahamas. B) Massive specimen from Curacao; note the surface aspect and the two different kinds of oscules. C) Massive specimen from Jamaica. D) Round, ball specimen from Barbados. E) Holotype from Jamaica (courtesy of J. Xavier).