Erylus formosus Sollas, 1886

Ugalde, Diana, Gómez, Patricia & Simões, Nuno, 2015, Marine sponges (Porifera: Demospongiae) from the Gulf of México, new records and redescription of Erylus trisphaerus (de Laubenfels, 1953), Zootaxa 3911 (2), pp. 151-183 : 153

Erylus formosus Sollas, 1886

( Figs. 2 A–D, 13A)

Selected synonymy: Erylus formosus Sollas, 1886:195 ; Wiedenmayer 1977:181; Gómez & Green 1984:85; Hajdu et al. 2011:81.

Material examined. CNPGG –1446 Alacranes reef (22°35'11.90”N 89°45'11.49”W), depth 15 m, 02/VII/2012.

Description. Massive sponge, consisting of a set of interconnected lobes, each provided with an apical oscule ( Fig. 13 A). Body measures 6 cm in height by 3.5 cm in width. Oscules 2.5–4 mm in diameter, tending to collapse once out of the water. The body wall has homogeneously distributed ostia. The sponge surface is smooth underwater but wrinkled once out of the water. The consistency is firm, slightly compressible. Its color in vivo is dark brown outside, light brown inside, all dark brown in alcohol.

Skeleton. Cortex consist of two layers, about 200 µm thick, the outer one, ectochrote with abundant microstrongyles tangentially placed, and below a thicker layer with aspidasters packed together. The choanosomal skeleton is radially oriented near the surface, becoming strewn in confusion at the centre ( Fig. 2 A). The orthotriaene rhabds are perpendicular to the surface, with cladomes supporting the cortex, and several bundles of oxeas 50–100 µm in diameter, some single oxeas traversing the cortex. Tylasters, oxyasters and centrotylote microstrongyles are scattered in the choanosome.

Spicules ( Figs. 2 B–D). Megascleres are fusiform oxeas, slightly curved to styloid, 600–900 × 12–18.2 µm, orthotriaenes with rhabdomes 385–550 × 18.2 µm in length, with clads around 143 × 13 µm. Microscleres are aspidasters, 150–213.2 µm long, centrotylotes microstrongyles for the most part with some centrotylote microxeas, 39–45 × 2.7-6 µm ( Fig. 2 D), tylasters 13–16.5 µm in diameter and oxyasters, 12–18 µm in diameter.

Distribution and ecology. The current is the first record of Erylus formosus for the Gulf of Mexico. However, it is well represented in the Caribbean Sea, from the north coast of Quintana Roo ( Gómez & Green 1984) to the south of Panama ( Díaz 2005), Carrie Bow Cay, Belize ( Rützler et al 2014) and the coast of Brazil ( Hajdu et al. 2011). It has even been recorded in eastern Florida, near Bimini Island, Bahamas, at 3 to 50 m depth ( Wiedenmayer 1977).

Remarks. Erylus formosus is very similar to E. trisphaerus (de Laubenfels 1953) (see below). However, it differs as its body lobes are close together, resulting in a massive complex of lobes, whereas the lobes in E. trisphaerus are well separated from each other. The color is brown alive in both species, but in E. formosus it is homogeneous throughout the whole body, whereas in E. trisphaerus it is blackish on top and light brown to beige towards the base of the sponge. The skeletal elements show the most important differences between these species, E. formosus differs from E. trisphaerus by aspidasters that are not trilobulate such as in E. trisphaerus ( Fig. 4 A) it is simply elongated ( Fig. 2 D). It mainly has microstrongyles instead of microxeas, and spicular meristics of megascleres differ on the average, are thinner and smaller in E. trisphaerus .

Figures

FIGURE 2. Erylus formosus Sollas, 1886: A. Cross section of skeletal arrangement showing the cortex and radial arrangement of megascleres. B. Aspidasters and centrotylote microstrongyles in LM. C. Oxeas and aspidasters. D. Aspidaster and centrotylotes microstrongyles in SEM.

FIGURE 4. Spicule composition in Erylus trisphaerus (de Laubenfels, 1953): A. Trilobate aspidasters at different stages of development, (from left, mature, to right, early). B. Hilum detail of aspidaster. C. Chiasters I with microspined rays. D. Chiasters II, smaller and lightly microspined. E. Oxyasters, minutely spined.

FIGURE 13. Sponges in situ A. Erylus formosus. B. Cliona amplicavata excavating on Lobatus gigas shell. C. Cliona flavifodina. D. Chondrilla caribensis, E. Hymeniacidon caerulea.