Haliclona (Reniera) stygobia, Gómez & Calderón-Gutiérrez, 2020

Gómez, Patricia & Calderón-Gutiérrez, Fernando, 2020, Anchialine cave-dwelling sponge fauna (Porifera) from La Quebrada, Mexico with the description of the first Mexican stygobiont sponges, Zootaxa 4803 (1), pp. 125-151 : 131-133

Haliclona (Reniera) stygobia sp. nov.

Fig. 4

Synonymy and other records. Haliclona (Reniera) sp. 2; Calderón-Gutiérrez et al. 2018:14, Table 1, S1 Table, S3 Table.

Material examined. HOLOTYPE CNPGG‒1481, Cenote S-1, La Quebrada anchialine cave system, Cozu- mel, Quintana Roo, Mexico (20°26’16.75’’N, 86°59’47.44’’W). Depth 4.5 m, January 12, 2015; coll. F. Calderón- Gutiérrez and German Yañez . PARATYPE CNPGG‒1482, same data as holotype.

Description. Subglobular shaped sponge, the two specimens are similar in size, 2.1‒2.3 cm long and 1.2‒1.9 cm wide. Color varies from beige to brown in vivo with a transparent dermal layer, turning to pale in alcohol ( Fig. 4a ). Surface irregular due to agglomerations of tissue, with protruding tips of spicules distant from each other; no oscular openings are clearly seen. Consistency extremely compressible, soft, and fragile that collapses with a slight move.

Skeleton. Ectosomal and choanosomal skeletons as a regular reticulation of single spicules making an isotropic net of unispicular tracts, forming triangular to rectangular meshes, 55‒458 µm wide ( Fig. 4 b-c).

Spicules. ( Fig. 4 d-g) Mainly oxeas, smooth, straight to slightly curved, fusiform, or sharply pointed, 82‒130 × 2.6‒3 µm. Some tending to smooth strongyles, straight to slightly curved with both ends tapering to a round point, others with a uniform diameter, 80.6‒117 × 2.6‒3 µm.

Etymology. Stygobia refers to its “stygobiont” habitat. Geographic distribution. Only known from the type locality. Ecology. This is a stygobite species. Observed in the cave through Cenote Km-1, but not after the Cenote Roca Bomba, at depths between 4.5 and 7.6 m, usually fixed on the floor, but also on the cave walls. In accordance with the quantitative survey, its population size along the cave was estimated as 9,729+/-3,079 individuals (Calderón- Gutiérrez et al. 2018 as H. ( Reniera ) sp. 2).

Remarks. At least six other species of Haliclona (Reniera) have been reported from marine cave environments, H. (R.) aquaeductus (Schmidt, 1862) , H. (R.) cinerea (Grant, 1826) , H. (R.) citrina (Topsent, 1892) , H. (R.) cratera (Schmidt, 1862) , H. (R.) mediterranea Griessinger, 1971 , and H. (R.) subtilis Griessinger, 1971 all recorded in the Mediterranean Sea (Griessinger 1971; Pouliquen 1972; Pulitzer-Finali 1983, De Weerdt 1986, 1989). Additionally, three more Haliclona (Reniera) species in the Caribbean have been reported in marine caves. H. (R.) implexiformis Hechtel, 1965 , originally from the reefs of Jamaica, but inhabits marine caves in the Bahamas ( Slattery et al. 2013) is characterized by its cushion shaped form, strongylote oxeas 95‒167 × 3.7‒9.3 µm, and pinkish-violet color. H. (R.) tubifera ( George & Wilson, 1919) is a thinly creeping branch or cushion-shaped with elevated small oscular tubes, oxeas 104‒171 × 2‒9.5 µm, and grayish color. H. (R.) mucifibrosa de Weerd et al. 1991 , is a thick-walled oscular chimney over a massive base, oxeas 186‒249 × 7.4‒13.5 µm, and grayish purple to bluish-gray color. All these Haliclona features differ from H. (R.) stygobia sp. nov. and no other Western Atlantic Haliclona or Haliclona (Reniera) matches with the present new species (see Table 1).

Figures

FIGURE 4. Haliclona (Reniera) stygobia sp. nov. a) Holotype CNPGG‒1482 (ethanol); b) ectosomal skeleton (tangential sec- tion, LM); c) choanosomal skeleton (cross section, LM); d-e) strongyle spicule (LM); f-g) oxea spicule (LM).