Jaspis eudermis Lévi & Vacelet, 1958

Sitjà, Cèlia & Maldonado, Manuel, 2014, New and rare sponges from the deep shelf of the Alboran Island (Alboran Sea, Western Mediterranean), Zootaxa 3760 (2), pp. 141-179 : 148-150

Jaspis eudermis Lévi & Vacelet, 1958

( Figs. 3A , 4 ; Table 2)

Material examined. Specimen MNCN-Sp71-BV10 collected from Stn. 10 ( Table 1 ; Fig. 1 ).

Comparative material: Holotype of Jaspis eudermis Lévi & Vacelet, 1957 ( MNHN DCL-738 ) from Princess Alice Bank, Azores (Stn. 62; 37º47’N 29º03’W, 330 m deep, 1955–1956).

Macroscopic description. Creamy white (in alcohol), cushion-shaped sponge, being 45 x 23 mm in size ( Fig. 3A ). Consistency firm, but friable. Surface nearly glabrous, covered by a friable, detachable, thick membrane (crust-like), with no discernible aquiferous openings. At the zones where the ectosomal crust is lost, subdermal aquifer canals of up to 1mm in diameter are evident.

Skeleton. Megascleres are oxeas, which seem to occur in two categories. Oxeas I are 1125–2000 x 20–40 µm and fairly abundant. They are once or twice slightly bent, frequently asymmetric, usually with acerate tips, occasionally blunt ( Fig. 4A–B ). Oxeas I showing irregular shapes are also occasional ( Fig. 4C ). Oxeas II are 390– 1500 x 5–10 µm, and comparatively quite scarce; they are slightly curved, sometimes centrotylote, and with conical or acerate ends ( Fig. 4A ). Microscleres are oxyasters, with 12–20 conical, smooth actines ( Fig. 4A, D ); their total diameter ranges from 20 to 65 µm, but with no discernible size categories.

There is an ectosomal, crust-like skeleton consisting of abundant oxyasters and tangential oxeas (mostly type II) irregularly disposed in small groups. The choanosomal skeleton consists of oxeas in disordered arrangement, along with abundant oxyasters.

Distribution and ecology notes. Rare species, previously known only from Azores (eastern North Atlantic). The only specimen herein collected from a gravel bottom at depths of 214–290 m provides the first record of the species in the Mediterranean Sea.

Taxonomic remarks. Several species of Jaspis occur in the Mediterranean or/and in the adjacent eastern North-Atlantic zone, but most of them have spicules clearly smaller than those of J. eudermis . The only exception is Jaspis incrustans (Topsent, 1890) , which has fairly large oxeas that reach 1250 µm in length. Nevertheless, oxyasters of J. incrustans measure only up to 26 µm in total diameter and their actines are clearly spiny rather than smooth ( Maldonado 1993).

Our material fits reasonably the only brief description available for J. eudermis , which corresponds to the holotype, a fragmentary, 2 x 2 x 1 cm, cushion-shaped sponge. It was reported to have a single category of 1200– 1650 x 45 µm oxeas (versus two in our specimens) and 35–45 µm oxyasters. The oxyasters were pictured by Lévi & Vacelet (1958) as having more than 10 actines with a smooth (not spiny) surface. Our revision of the holotype indicates that there are indeed two size categories of oxeas, discernible not only because of their thickness (1225– 1725 x 30–60 µm and 660–850 x 8–10 µm, with some occasional transitional stage), but also because of their shape, being the smaller category isodiametric and more markedly curved than the fusiform oxeas of the larger category. This reinterpretation of the oxea size distribution brings our specimen and the holotype in full skeletal agreement, as they also share the general traits of the macroscopic morphology and skeletal architecture. Furthermore, they both are the only Jaspis material in the Atlantic-Mediterranean region having large, "smooth" oxyasters with more than eleven actines. In this regard, our SEM re-examination of the holotype provides new interesting information. The oxyasters of the holotype measure 30–55 µm in total diameter and have 16 to 20 actines. Most of the actines are entirely smooth ( Fig. 4E ), as it also happens consistently in the Alboranian specimen ( Fig. 4D ). Nevertheless, under high SEM magnification approximately 20% of the oxyasters of the holotype show subtle microspines in one or more of their actines ( Fig. 4F ). In very few occasions, large, isolated spines also occur ( Fig. 4E ). Therefore, the "smooth" nature of the actines of J. eudermis is to be assessed in further detail when more specimens are collected.

Figures

FIGURE 1. (A) Localization of the Alboran Island in the Mediterranean. (B) Distribution of the 25 studied sampling stations over the bathymetric map of the shelf of the Alboran Island.

FIGURE 3. (A) Specimen of Jaspis eudermis Lévi & Vacelet, 1958 collected from the Alboran Sea and photographed on graphic paper (MNCN-Sp71-BV10). (B) Three Alboranian specimens of Hemiasterella elongata Topsent, 1928 (from left to right, MNCN-Sp66-BV21, MNCN-Sp66 B & A).

FIGURE 4. Jaspis eudermis Lévi & Vacelet, 1958: (A) Line drawing of the spicule complement of the Alboranian specimen (MNCN-Sp71-BV10), consisting of oxeas I (a) with acerate or blunt ends (b), oxeas II (c) with acerate or conical ends (d), and oxyasters (e). (B) Light microscope micrographs of oxeas I (a) and oxeas II (b). (C) An abnormal end (ab) of an oxea I next to an oxyaster (ox). (D) SEM micrograph of an entirely smooth oxyaster. (E) SEM image of several oxyasters of the holotype of J. eudermis (Stn. 62 MNHN DCL738), one having some large spines (sp) on some actines. (F) Detail of an oxyaster actine of the holotype showing minute spines (sp).