Calyx maya, 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 : 129-131

Calyx maya sp. nov.

Fig. 3

Synonymy and other records. Dendroxea sp. Calderón-Gutiérrez et al. 2018:S1 Table.

Material examined. HOLOTYPE CNPGG‒1630, Cenote S-1, La Quebrada anchialine cave, Cozumel , Quin- tana Roo, Mexico (20°26’16.75’’N, 86°59’47.44’’W). Depth 5.6 m, October 25, 2015; coll. F. Calderón-Gutiérrez and G. Yáñez.

Description. It is a delicate branching sponge, comprised by two thinly twigs 11 cm long, and each up to 2 mm in diameter, anastomosed at the middle. A basal plate that supports the body is lacking. Color yellowish-white in vivo with a transparent dermal layer ( Fig. 3a ), the color fades when in alcohol. Surface conulose-looking, consisting of protruding three to four aligned spicules, reaching up to 1 mm outside the surface, the same covered by a delicate dermis. Several scattered oscules up to 1 mm in diameter ( Fig. 3b ). Consistency compressible and soft.

Skeleton. ( Fig. 3 b-c) The ectosomal skeleton is a tangential unispicular layer of oxeas. The choanosomal skeleton is composed by a central longitudinal tract running along the twig. From this axial tract departs an ill-defined unispicular reticulation tending to isodyctial, (forming triangular to rectangular meshes), that also connects to thinner longitudinal multispicular tracts (up to 33.4 µm in diameter) parallel to surface. Many scattered spicules are in between. Collagenous matrix in a relatively low density.

Spicules. ( Fig. 3 d-e) Oxeas hastate, straight and slightly curved, with both conical and telescoped ends, 171.6‒ 215 × 2.8‒7 µm. A second category of oxeas is a thinly fusiform oxea, 110‒179.6 × 1.5‒4.4 µm. Strongyles in lesser number, straight to slightly curved also, 106‒210 × 7.5‒9 µm ( Fig. 3e ). Frequent swellings or tubercles occur at the middle part of the shaft, as much of strongyles as of the thinner oxeas.

Etymology. The species name refers to the Maya civilization that settled in this area.

Geographic distribution. Only known from the type locality.

Ecology. This is a stygobite species, living at 5.6 m depth. This is the first record of the genus Calyx in anchialine caves. Apart from this, no individuals fell inside the transects of the quantitative survey, indicating a low population size ( Calderón-Gutiérrez et al. 2018 as Dendoxea sp.).

Remarks. According to Desqueyroux-Faúndez & Valentine’s (2002) definition of the genus, Calyx maya sp. nov. agrees well enough with it. The new species only differs for having a single unispicular layer in the ectosomal skeleton instead of a multi-layer as diagnosed in the genus, owing most probably to the small size and highly delicate branched growth form. The unispicular layer could be an adaptation to the low food availability in the cave environment.

Calyx maya sp. nov. is distinguished from the two Tropical Western Atlantic Calyx species, by the presence of its thinly branching habit, a single unispicular layer in the ectosomal skeleton, its variable shaped oxeas from hastate, fusiform, through stair-stepped to strongyle. Besides, a good percentage of spicules of the new species have a tuberous centrotylote on the oxeas, which is absent in both C. podatypa (de Laubenfels 1934 as Haliclona ) and C. magnoculata van Soest et al. 2014 . C. podatypa is characterized by a choanosomal sub-rectangular reticulation containing multispicular tracts, and among these many interstitial spicules that make vague isodictyal reticulations; along with its massive body, a denser ectosomal skeleton, key shaped oscules, and smaller spicule sizes, 90‒119 × 2‒4 µm. Van Soest (2017) re-measured the holotype spicules of C. podatypa USNM 22305, uniform in size and shape, and curved thin oxeas, 117‒133‒144 × 2.5‒3.8‒ 5 µm, still different from our new species. C. magnoculata is characterized by its massively encrusting growth form, a dense multilayered crust of intercrossing spicules, and mostly, an isotropic-confused spicule mass at the choanosome, as well as slightly larger spicules (141‒264 × 6‒13 µm).

Figures

FIGURE 3. Calyx maya sp. nov. a) Holotype CNPGG‒1630 (ethanol); b) ectosome (tangential section, LM); c) skeleton, conule-type (arrows) with 3-4 aligned megascleres (longitudinal section, LM); d) oxea spicules (LM); e) strongyle spicules (LM).