Myrmekioderma rea (de Laubenfels 1934 )

Ugalde, Diana, Fernandez, Julio C. C., Gómez, Patricia, Lôbo-Hajdu, Gisele & Simões, Nuno, 2021, An update on the diversity of marine sponges in the southern Gulf of Mexico coral reefs, Zootaxa 5031 (1), pp. 1-112 : 19-20

Myrmekioderma rea (de Laubenfels 1934)

Tables 6, 7; Figs. 12A–G , 16L

Synonymy and references: Anacanthaea rea de Laubenfels (1934: 11) ; Epipolasis rea , Epipolasis reiswigi and Myrmekioderma styx : see references compiled in Muricy et al. (2011: 96); Myrmekioderma rea: Muricy et al. (2011: 96) , Rützler et al. (2014: 72), Pérez et al. (2017: 11), and van Soest (2017: 56).

Type locality. Puerto Rico .

Material examined. CNPGG-2261, Triangulo Oeste reef (20.95629°N, - 92.308609°W), 8 m depth, coll. Oscar Bocardo, 10 September 2017 ; CNPGG-2433, Cabezo reef (19.05086°N, - 95.82388°W), 8.3 m depth, coll. Diana Ugalde, 30 August 2018 .

Description. Massive habit; larger specimen size 7.5 × 5 × 3 cm ( Fig. 16L ). Surface slightly irregular, covered by sand and calcareous debris. Pores are not visible. Oscules scattered up to 2 mm diameter. Color in vivo orangishyellow, pinkish beige preserved in ethanol. Consistency firm and slightly resilient.

Skeleton. The ectosomal region is constituted by acanthoxeas perpendicular to the surface in a palisade-like structure ( Fig. 12A ). Some acanthoxeas in a paratangential and criss-cross arrangement ( Fig. 12B ). It is covered by a crust of sand grains and calcareous debris, up to 200 µm thick. Choanosomal region with longitudinal tracts (up to 120 µm thick) of large oxeas towards the surface. The large oxeas are also scattered in between. Raphides scattered throughout the skeleton; in trichodragmas. Rounded channels, up to 100 µm diameter, are horizontally aligned beneath the palisade of acanthoxeas. Channels scattered in the choanosome, up to 130 µm in diameter. Scattered debris was also found in the choanosomal region ( Fig. 12B ).

Spicules. Megascleres: Large oxeas with styloid and strongylote modifications, stout, slightly curved to sinuous, some forms double bent, and smooth ( Fig. 12C ). The tips are conical, stepped, or blunt; 535– 807 (161.3)– 1110/8– 11.5 (1.5)–14 µm ( Figs. 12D–E ). Acanthoxeas are slightly curved to sinuous; some are double bent, covered irregularly with minute spines, sometimes smoother at the middle region ( Figs. 12F–G ). With sharp and acerate tips; 235– 362 (48.9)–420/7.2– 10.7 (2)–14 µm. Microscleres: raphides very thin; 120– 150.3 (20.7)–180 µm in length.

Distribution. Mexico (current records), US (Florida), Barbados, Bahamas, Cuba, other countries in the Caribbean Sea ( Diaz et al. 1993); Guyana ( van Soest 2017).

Remarks. Van Soest (2017) believed the observed variability in Guyana’s specimens obtained from the same trawl (98 m and 65 m depth) was intraspecific. He observed variation in the habit (i.e., broad knoll, club-shaped body or finger-shaped body) and spiculation (i.e., the shape of oxeas and number of categories of oxeas and raphides). We extend this intraspecific variation of M. rea by considering specimens from Belize ( Rützler et al. 2014) and the GoM (present study), both no deeper than 20 m. These specimens have massive cushion shape habits. In adition, spicule measurements of the Mexican specimens analyzed in our study (particularly of oxeas) are thinner than those in specimens from Belize and Guyana. However, in general, our material’s spicule measurements are more similar to specimens from Belize than the ones from Guyana ( Table 1).

Intraspecific variation of Myrmekioderma rea can be observed in Brazilian specimens too ( Rosa-Barbosa 1995, Mothes et al. 2004, 2006). They were all reported with a massive habit, similar to our material’s and Belize’s ( Rützler et al. 2014), but devoid of raphides in northern Brazil ( Mothes et al. 2004), and possessing styles (744.2– 1497/10–23.9 µm) and small trichodragmas (23–92/4.6–13 µm) in materials reported by Mothes et al. (2006), from southern Brazil. These variations deviate from typical spiculation of M. rea in specimens from Guyana, the Caribbean region, and the GoM (our material) ( Table 1). Previous and the present records of M. rea are from shallow to mesophotic depths on coral reefs (de Laubenfels 1953; van Soest & Stentoft 1988; Díaz et al. 1993; Rützler et al. 2014), and from muddy sand bottoms down to 100 m depth ( van Soest 2017).

Order Biemnida Morrow, 2013

Figures

FIGURE 12. Myrmekioderma rea (de Laubenfels, 1934) (CNPGG-2261), skeleton and spicules: A. ectosomal region in a transversal section of the skeleton; B. acanthoxeas in a paratangential and criss-cross arrangement in a transversal section of the skeleton, C. general view of stylote and strongylote oxeas, and acanthoxeas; D. strogylote oxea; E. oxea; F–G. acanthoxea. Scale bars: A–B = 200 µm; C = 100 µm; D–G = 50 µm.

FIGURE 16. In situ photographs of species analyzed in the present study: A. Agelas clathrodes (Schmidt, 1870) (CNPGG- 2297); B. Agelas conifera (Schmidt, 1870) (CNPGG-2373); C. Agelas dispar Duchassaing & Michelotti, 1864 (CNPGG-2007); D. Agelas schmidtii Wilson, 1902 (CNPGG-2285);E. Agelas sventres Lehnert & van Soest, 1996 (CNPGG-2285); F. Agelas wiedenmayeri Alcolado, 1984 (CNPGG-2476); G. Prosuberites carriebowensis Rützler, Piantoni, van Soest & Díaz, 2014 (CNPGG-2211); H. Ectyoplasia ferox (Duchassaing & Michelotti, 1864) (CNPGG-2407); I. Ectyoplasia ferox (Duchassaing & Michelotti, 1864) (CNPGG-2240); J. Dragmacidon reticulatum (Ridley & Dendy, 1886) (CNPGG-2283); K. Ptilocaulis walpersii (Duchassaing & Michelotti, 1864) (CNPGG-2171); L. Myrmekioderma rea (de Laubenfels, 1934) (CNPGG-2261); M. Neofibularia nolitangere (Duchassaing & Michelotti, 1864) (CNPGG-2206); N. Desmanthus meandroides van Soest & Hajdu, 2000 (CNPGG-2389); O. Cliona aprica Pang, 1973 (CNPGG-2298). Scale bars, A–O = 1 cm.