Cladocroce infundibulum, Lehnert, Helmut & Stone, Robert P., 2013

Lehnert, Helmut & Stone, Robert P., 2013, Four new species of Haplosclerida (Porifera, Demospongiae) from the Aleutian Islands, Alaska, Zootaxa 3700 (4), pp. 573-582 : 577-578

Cladocroce infundibulum n. sp.

(Fig. 3)

Material examined. Holotype: USNM# 1202118, collected by Jim Stark on 2 August 2012 at 52°56.22´N, 170°59.29´E on Stalemate Bank, 97.6 km W of Cape Wrangell, Attu Island, western Aleutian Islands, Alaska, USA, at a depth of 185 m and a water temperature of 3.6°C.

FIGURE 3. Cladocroce infundibulum n. sp. A. Holotype, grid marks are 1 cm 2. B. Choanosome: two spicule tracts run through the choanosomal reticulation of paucispicular tracts and single spicules. One runs from the upper left quarter of the photo vertically downwards and the second from the same starting point is running at approximately 45° downwards to the right. Scale bar is 250 µm. C. Close-up of independent spicule tract between choanosomal reticulation horizontal through the center of the photo. Scale bar is 250 µm. D. SEM photo of the oxeas.

Description. The holotype (Fig. 3A) is a funnel-shaped, stalked, golden brown to light brown sponge. The stalk is approximately 1 cm in diameter in the middle and widens to almost 2 cm at the point of attachment to a pebble (4.6 cm in diameter). The stalk is almost 5 cm long and has a smooth surface, macroscopically different from the highly porous surfaces of the funnel. From the stalk the funnel widens gradually to a maximum diameter of about 17 cm and reaches a height of about 18 cm. The irregular outline of the upper margin of the funnel and many different sized apertures give the funnel a ragged appearance. The inner surface of the funnel bears larger pores than the outer surface. The thickness of the funnel wall is 5-6 mm. The specimen was partially fragmented upon collection and tears somewhat easily if torn perpendicular to the fibre tracts running through the sponge but otherwise is of firm consistency and resilient. The sponge is only slightly elastic. There is no special ectosome developed. The choanosome consists of ascending paucispicular tracts which are connected by single spicules.

Between this meshwork run independently pauci- to polyspicular tracts (Figs. 3B & C). These can be seen by the unaided eye where the sponge was torn and picked out of the skeleton of the sponge with a forceps. These fibres are 2–3 cm long and vary in width from 42–128 µm. Spicules are relatively straight and thick oxeas, 232–281 x 19–23 µm (Fig. 3D).

Discussion. T he WPD (Van Soest et al. 2013) lists 12 records for Cladocroce . We compared the new species with congeners from the North Pacific, Arctic and North Atlantic Oceans. Thus we compared the new species with six species of Cladocroce: Four of them have smaller and thinner oxeas: C. parenchyma (Lundbeck, 1902) from the North Atlantic (oxeas, 238 x 9–12); C. reina Aguilar-Camacho & Carballo, 2010 from the Pacific Coast of Mexico (oxeas, 130–175 x 5 –7.5 µm); C. spatula (Lundbeck, 1902) from the North Atlantic (oxeas, 190–220 x 10– 12 µm); C. ventilabrum (Fristedt, 1897) from the Arctic Ocean, the Aleutian Islands, and the Sea of Japan (oxeas 210–265 x 12–14 µm). Judging from fig. 8, pl. 27 (Fristedt (1897) C. ventilabrum is flabellate with a smoother surface than C. infundibulum . The remaining two species have considerably larger oxeas: C. fibrosa Topsent, 1890 (oxeas 600 x 18 µm) and C. spathiformis Topsent, 1904 (oxeas 375 x 17 µm) both from the North Atlantic Ocean. The three species of Cladocroce described here differ in size and shape, in the abundence and thickness of the diagnostic spicule tracts, and in the dimensions of the occurring oxeas. C. infundibulum has the thickest oxeas, C. attu has the shortest oxeas, while C. kiska contains the longest oxeas with sigmas.

The specimen was collected remotely with a research trawl so we did not visually observe the seafloor habitat where the specimen resided. However, the specimen was attached to a jagged pebble at a depth of 185 m that would indicate that this species is found on relatively flat habitat consisting of unconsolidated sediments with pebbles.

Etymology. The species name is from the Latin noun “ infundibulum ” meaning “funnel”, referring to the growth form of the species.