Ecionemia megastylifera Wintermann-Kilian & Kilian, 1984

Cárdenas, Paco, Menegola, Carla, Rapp, Hans Tore & Díaz, Maria Cristina, 2009, Morphological description and DNA barcodes of shallow-water Tetractinellida (Porifera: Demospongiae) from Bocas del Toro, Panama, with description of a new species, Zootaxa 2276, pp. 1-39 : 12-15

Ecionemia megastylifera Wintermann-Kilian & Kilian, 1984

( Figures 5–6–7 )

Synonyms.

Ecionemia megastylifera Wintermann-Kilian & Kilian, 1984: 122 , figs. 1–2. Ancorina megastylifera (Wintermann– Kilian & Kilian, 1984): Alcolado 2002: p. 56. Stellettinopsis dominicana Pulitzer-Finali, 1986: 67 , figs. 1–2 (new synonym). Ecionemia dominicana ( Pulitzer-Finali, 1986) : Rützler et al. 2000: Table 1 (new synonym).

Holotype. INVPOR 1148, Bahia Nenguange, Colombia, 3 m depth.

Material. 5 specimens, from STRI Point, Solarte Island and Bastimento Island, 0.4–20 m depth. Two specimens deposited: ZMBN 81782–81783.

Additional material examined. Ecionemia megastylifera , INVPOR 1148, holotype, Bahia Nenguange, Colombia, 3 m; ZMAPOR 7772, Bahamas; ZMAPOR 14265, off Slangebaai, Curacao, 3.8 m. Ecionemia dominicana ( Pulitzer-Finali, 1986) , MSNG 47679, holotype, Boca Chica, Dominican Republic, 15– 25 m. Ecionemia demera (de Laubenfels, 1934), MNHN DNBE- 17, slide of holotype, Puerto Rico, 60–73 m; ZMAPOR 0 3512, Puerto Rico.

Outer morphology ( Fig. 5 A–D). Thickly encrusting to massive lobate sponge. One very large specimen found on coral rubble in Solarte south was sub-circular, 8 cm high and with a diameter of 15 cm ( Fig. 5 B); it had cemented and integrated coral rubble pieces. Other specimens had an elongated shape and were 20 cm long ( Fig. 5 C). Surface is rugose. Slightly compressible. Choanosome has a hairy aspect due to the high density of large oxeas. External color on living specimen and in ethanol is light brownish to black. Internal color on living specimen is whitish to cream, whitish in ethanol. Oscules are 3–10 mm of diameter and distributed on the top surface of the sponge ( Fig. 5 A–C). There is a thin contractile membrane around the oscule. Oscules lead into one or more cloacae chambers where uniporal exhalant openings are present. Pores are cribriporal ( Fig. 5 D) and evenly distributed over large surfaces of the sponge, there is no separation between pore plates. A single pore plate has a diameter of around 0.5 mm. Macro-epibionts (e.g. sponges, algae) can be found growing on large specimens. Gammarid amphipods were found living in an oscule.

Skeleton ( Fig. 5 E). Small acanthostrongylasters lay on a paratangential layer of acanthomicrorhabds, thus forming a very thin cortex (ca 140–170 µm thick) supported by bundles of long–shafted robust dichotriaenes. Thin microxeas, sometimes in bundles, cross the cortex. In certain parts where the sponge is hispid, large oxeas, dichotriaenes, anatriaenes and protriaenes also cross the cortex. Sub-cortical canals cross transversely this layer of triaenes. Under the triaenes, large oxeas paratangentially positioned form a dense layer (ca 1.2 mm thick). Deeper, this arrangement becomes looser and more irregular; oxeas II, some dichotriaenes and rare anatriaenes can be found there also. Acanthoxyasters are found dispersed in the choanosome, and are abundant around canals. Large granular cells (diameter: 16–27 µm) are especially abundant in the cortex but are also present, albeit in lower density, in the choanosome. The cortex of cloacae chambers is somewhat different. It has fewer acanthomicrorhabds and is not supported by triaenes; it is mainly tangential large oxeas that stretch and support the acanthostrongylaster layer. It is only crossed by a few microxeas.

Spicules (measurements of ZMBN 81782, except for protriaenes, only found in ZMBN 81783) ( Figs. 6– 7 ). Megascleres: (a) oxeas I, very large, slightly bent, sometimes modified to styles, length: 1332– 1524 –1764 µm; width: 56– 64.9 –70 µm. (b) oxeas II, straight or slightly bent, length: 520– 815.2 –1260 µm; width: 14– 22.9 –42 µm. (c) microxeas, usually straight but can be slightly bent, length: 182– 215.4 –317 µm; width: 2.5– 4 –5 µm. (d) dichotriaenes to orthotriaenes, stout, rare in some specimens, the rhabdome can be slightly bent, and in some rare cases extra spines are present, thus becoming acanthotriaenes, rhabdomes can have an oxeote or strongylote end, rhabdome length: 790– 997.6 –1222 µm; width: 50– 64.7 –80 µm; clad length: 120– 151.7 – 180 µm (some young triaenes observed, rhabdome length: 400– 530 –651 µm; width: 18– 27 –41 µm; clad length: 53– 76.2 –104 µm). (e) anatriaenes, rare, rhabdome slightly inflated, rhabdome length: 228– 278.3 –334 µm (N=3); rhabdome width: 1– 1.3 –2 µm (N=6); clad length: 3– 4 –5 µm (N=6). (f) protriaenes, rare, sometimes modified to mesoprotriaenes, rhabdome length: 417 µm (N=1); rhabdome width: 2.5– 3.75 –5 µm (N=2); clad length: 27– 32.5 –38 µm (N=2). Microscleres: (g) acanthomicrorhabds ( Fig. 6 A), with oxeote or strongylote ends, sometimes centrotylote, length: 59– 98.6 –138.3 µm; width: 4.5– 8.2 –10.6 µm. (h) acanthoxyasters ( Fig. 6 B), 6–9 actines, a characteristic spike at the end of each actine, diameter: 9– 13.1 –19 µm. (i) acanthostrongylasters ( Fig. 6 C), 4–11 actines, diameter: 4– 6.7 –10 µm.

Habitat in the Bocas del Toro region. Common in coral rubble or in sheltered areas of reefs (such as small cavities). Usually sciophilous 1–25 m depth.

Distribution. Bahamas (this study); Cuba ( Alcolado 2002); Dominican Republic ( Pulitzer-Finali 1986); Belize ( Rützler et al. 2000); Costa Rica ( Cortés 1996); Panama (this study); Colombia ( Wintermann-Kilian & Kilian 1984; Valderrama 2001; Díaz 2007); Curaçao (this study).

Remarks and discussion. This species possesses true spiny microrhabds ( Fig. 6 A) (not sanidasters) so it does not belong to the Ancorina genus. The original description by Wintermann– Kilian and Kilian (1984) mentions only one size class of euasters, but after reexamination of the holotype it is quite obvious that there are two kinds of euasters: the small strongylasters placed in the ectocortex and the larger oxyasters in the choanosome. Wintermann– Kilian and Kilian (1984) note the presence of microstrongyles, but these are simply variations of microrhabds. They also overlooked the presence of microxeas present in the holotype ( Fig. 6 E). Furthermore, we observed in the Bocas material and the holotype two size classes of oxeas that had not been identified before. There were some differences between the Bocas del Toro specimens and the holotype. The holotype had smaller oxeas, smaller triaenes ( Fig. 6 D), thinner and smaller microrhabds ( Fig. 6 E) (length: 48– 69.2 –92, width: 2– 3.1 –5), smaller microxeas, asters with thinner actines ( Fig. 6 F), and more oxeas II (most of them found under the oxea I layer) ( Fig. 5 F). Anatriaenes and protriaenes observed in the Bocas del Toro specimens were not found in the holotype. The holotype of E. dominicana had also two size classes of euasters and the microxeas, both of which had been overlooked by Pulitzer-Finali (1986). The microrhabds’ measurements in the E. dominicana holotype were very similar to those found in the holotype of E. megastylifera . As a result of these observations, E. dominicana becomes a junior synonym of E. megastylifera . Lehnert (1993) also described a Stelletinopsis sp. in Cozumel ( Mexico) which resembles E. megastylifera . However, the vase shape, the blue and yellow colors and the absence of triaenes do not match with our species. The other Caribbean species of Ecionemia , E. demera from Puerto Rico differs from E. megastylifera in having plagiotriaenes, much larger anatriaenes, smaller acanthomicrorhabds (ca 7 µm) and only one kind of euasters. The dark color of E. megastylifera is due to large pigmented cells, more or less present with respect to light conditions. These pigments may serve for light protection since their abundance is greater in light environments; this has been suggested in other sponges ( Renouf 1934; Bandaranayake et al. 1996; Cavalcanti et al. 2007; Valderrama et al. 2009). This is the species collected in Bocas del Toro by Nichols (2005) and identified as Ecionemia sp. We sequenced three of our specimens and obtained strictly identical COI sequences as Nichols (2005).

Figures

FIGURE 5. Ecionemia megastylifera Wintermann-Kilian & Kilian, 1984: A. Dark specimen found growing under coral rubble (1 m depth). Arrows point to its oscules. Scale: 4 cm; B. Large dark specimen found on Solarte South 4 (0.4 m depth) growing on coral rubble. It is covered with sediments and overgrown by sponges (Chondrilla aff. nucula and Amphimedon erina) and algae. Scale: 5 cm; C. Elongated coffee – colored specimen collected in a small cavity on Sache (15 m depth); D. Close up of the surface (dried) revealing the cribriporal pores. Scale: 0.5 mm; E. Cross – section showing the skeletal architecture: cortex and choanosome [ZMBN 81782]. Scale: 1 mm; F. Cross – section of cortex and choanosome [INVPOR 1148, holotype]. Scale: 1 mm.

FIGURE 6. Ecionemia megastylifera Wintermann-Kilian & Kilian, 1984 [ZMBN 81782]: A. Microrhabd and acanthostrongylaster. Scale: 10 µm; B. Acanthoxyaster. Scale: 2 µm; C. Acanthostrongylaster. Scale: 2 µm; E. megastylifera [INVPOR 1148, holotype]: D. Young triaene. Scale: 20 µ m; E. Microxea, microrhabd and acanthostrongylaster. Scale: 10 µm; F. Acanthostrongylasters. Scale: 2 µm.

FIGURE 7. Spicule repertoire of Ecionemia megastylifera Wintermann-Kilian & Kilian, 1984. A. Oxea I; B. Oxea II; C. Dichotriaene; D. Cladome of protriaene; E. Cladome of anatriaene; F. Acanthomicrorhabds; G. Microxeas; H. Acanthotylaster; I. Acanthoxyaster. Scale 200 µm for A – B – C and F – G. Scale 20 µm for D – E. Scale 2 µm for H – I.