Haliclona (Gellius) megasclera Lehnert & van Soest, 1996

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 : 34-35

Haliclona (Gellius) megasclera Lehnert & van Soest, 1996

Tables 6, 7; Figs. 26A–D

Synonymy and references: Haliclona megasclera Lehnert & van Soest (1996: 73) ; Haliclona (Gellius) megasclera , present study.

Type locality. Jamaica .

Material examined. CNPGG-2379, Banco Obispo Sur reef (20.50072°N, - 92.20306°W), 11 m depth, coll. Oscar Bocardo, 13 September 2017.

Description. Encrusting habit; seen in a fragmented specimen, size of the fragment: 1.6–3.2 × 0.15 cm. The surface is microhispid without visible pores or oscules. Color in vivo not recorded, light beige in ethanol. Consistency highly compressible and slightly friable.

Skeleton. Tangential skeleton with a unispicular reticulation, and several scattered spicules ( Fig. 26A–B ). Choanosomal skeleton is an irregular reticulation of paucispicular primary lines, 2–3 spicules thick ( Fig. 26C ). Some subdermal lacunae, up to 250 µm in diameter beneath the ectosomal region, and channels up to 500 µm in diameter in the choanosomal region. Some raphid-like growth stages of oxeas throughout the skeleton.

Spicules. Megascleres: Oxeas are slightly curved and smooth, in a large size range; the juvenile forms are thinner ( Fig. 26D ). Tips sharp, acerate to hastate; 280– 355.3 (46.9)–440/8.5– 10.4 (1.3)–12 µm.

Distribution. Mexico (current records), Jamaica ( Lehnert & van Soest 1996).

Remarks. Haliclona (G.) megasclera has been described only in Jamaica ( Lehnert & van Soest 1996); therefore, our study is the second record of the species and the first record for the GoM, as well as the first from a shallower habitat. The material examined conforms well to the general outline, skeleton, and spicule sizes, according to the expected for H. (G.) megasclera . Its massive habit that was not encountered in our collecting dives should probably be due to the different depths and evident environmental differences. The slightly larger oxeas in our material do not distort the average range of 282–370/9–12 µm in the type material. Besides, the large-sized oxeas are the main trait of H. (G.) megasclera compared to other Caribbean Haliclona (Gellius) species. Despite that, no striking differences appear over the two morphs, massive habit at 77 m depth, and encrusted habit at 11 m; both include the same overall traits.

Subgenus Haliclona (Reniera) Schmidt, 1862

Figures

FIGURE 26. Haliclona (Gellius) megasclera Lehnert & van Soest, 1996 (CNPGG-2379), skeleton and spicules: A. tangential section of the ectosomal skeleton; B. transversal section of the skeleton of the choanosomal region near to surface; C. transversal section of the skeleton of the choanosomal region; D. oxeas, 1— juvenile forms raphides-like oxeas and 2—raphides. Scale bars: A = 250 µm; B–100 µm; D = 25 µm.