Leuceta conspicua, Klautau & Lopes & Tavares & Rizzieri & Sorokin & Fromont & Goudie & Crowther & McCormack & George & Wahab, 2025

LeuceTa conspicua sp. nov.

( Figs 17, 18; Table 9)

Zoobank registration: urn:lsid:zoobank.org:act:

Etymology: For the conspicuous cortex of this species (Latin conspicuus = conspicuous).

Diagnosis: Leuceta with a conspicuous cortex formed only by small triactines. Choanosome composed of large triactines and small triactines and tetractines. Te tetractines are restricted mainly to the inhalant canals. Atrial skeleton with triactines.

Type material: Holotype, SAMA S1854, GAB, 35°02 ʹ 17″S, 135°05 ʹ 42″E, depth: 221 m, coll: GABRP, site IN2015 _ C02_128, 4 December 2015. GoogleMaps

Colour: Brown in ethanol ( Fig. 17A).

Morphology and anatomy: Sponge amorphous, massive, consistency firm and hard or friable. Osculum apical and large. Surface smooth but with ridges ( Fig. 17A). Te body wall is 0.4 cm thick and full of canals. Te atrium is large ( 1.5 cm), smooth, with several spherical exhalant canals. Aquiferous system leuconoid.

Te cortical skeleton is thick and conspicuous, composed of small triactines ( Fig. 17B–D), which are also present in the choanosome ( Fig. 17E) and in the atrium ( Fig. 17F); however, they are frequently larger (>13 µm) in the cortical and atrial skeletons than in the choanosome. Immediately below the cortex are inhalant canals ( Fig. 17D). Te choanosome has the small triactines, large triactines, and tetractines ( Fig. 17E). Tese tetractines surround the canals, which are also surrounded by the small triactines ( Fig. 17F). Te tetractines are present mainly in the inhalant canals. Near the atrium there are several exhalant canals supported by triactines. Te atrial skeleton is thin, composed only of triactines and tetractines ( Fig. 17F).

Spicules ( Table 9)

Large triactines: Regular (equiangular and equiradiate). Actines are conical, with sharp tips ( Fig. 18A) and variable sizes. Size: 540.5 (±158.9)/68.6 (±18.3) µm.

Small triactines: Regular (equiangular and equiradiate). Actines are conical, with blunt tips ( Fig. 18B). Size: 129.2 (±21.1)/11.4 (±1.8) µm.

Small tetractines: Regular or sagital. Actines are conical, with blunt tips ( Fig. 18C). Te apical actine is smooth and very thin (needle-like; Fig. 18D), but thick apical actines were found in the bigger spicules. Tey are rarer than the thin apical actines. Size: basal, 161.5 (±20.6)/14.4 (±2.5) µm; apical, 113.1 (±101.8)/7.8 (±3.2) µm.

Geographical distribution: Currently known from only the type locality in the GAB.

Ecology: Tis species was found at a depth of 221 m on the edge of continental shelf (in fine sand and silt).

Taxonomic remarks: Te current diagnosis of Leuceta is: ‘ Leucetidae with a homogeneous organisation of the wall and a typical leuconoid aquiferous system. Tere is neither a clear distinction between the cortex and the choanoskeleton, nor the presence of a distinct layer of subcortical inhalant cavities (lacunae). Te atrium is frequently reduced to a system of exhalant canals that open directly into the osculum, or it may be a large cavity’ (Borojević et al. 2002, Valderrama et al. 2009).

Te new species does not fit exactly within this diagnosis because it has a conspicuous cortex. Considering that some Leuceta species have spicule categories restricted to the cortex and that Leuceta conspicua has a conspicuous cortex and grouped with other species of Leuceta and Pericharax in our molecular tree, we propose the following new diagnosis for Leuceta : Leucetidae with a typical leuconoid aquiferous system. Most species have no clear distinction between the cortex and the choanoskeleton. A distinct layer of subcortical inhalant cavities (lacunae) is not present, but sometimes the body wall is full of canals. Te atrium is reduced to a system of exhalant canals that open directly into the osculum, or it is a large cavity.

We compared this specimen with all the known species of Leuceta and Pericharax , considering that these genera are not monophyletic and can be synonymous. To our knowledge, all the specimens of both genera do not have a conspicuous cortex as Leuceta conspicua does, indicating that it is indeed a new species.