Ancorina buldira

Ancorina buldira n. sp

(Fig. 4)

Material examined. Holotype, ZSM 20140113, in three pieces: large and small fragment dried and small fragment in ethanol, collected by Jim Stark with a research survey bottom trawl from the FV Ocean Explorer; 26 July 2012, 234 m depth, 34 km WSW of Buldir Island, western Aleutian Islands, North Pacific Ocean (52°17.16” N, 175°21.48” E). Probably attached to a mass of sand and pebbles. Bottom water temperature = 3.7 °C.

Description. Large, massive, light brown coloured sponge (in life), dimensions 23 cm x 18 cm x 6.5 cm (Figs. 4A–B). Hard, only slightly elastic consistency. Habitus similar to Geodia starki Lehnert et al., 2013. In sections perpendicular to the surface, there is a whitish collagenous cortex, 500–800 µm in thickness and up to 15 mm below the surface (Fig. 4B). Polyspicular tracts of megascleres radiate through the cortex, 800–1100 µm in diameter in the cortex and fanning out to form a dense spicule brush (Fig. 4B). Right below the cortex and between the polyspicular tracts oval-shaped canals are visible, 400 x 800 µm in diameter at intervals of approximately 1 mm. A reddish brown to dark brown choanosome, where the arrangement of spicule tracts becomes more irregular, is visible below the oval canals (Fig. 4B). Spicules are long, abundant plagiotriaenes (Fig. 4C), straight rhabds up to 8000 x 180 µm, more rare protriaenes (Fig. 4F), anatriaenes (Fig. 4D), relatively small but thick dichotriaenes (Fig. 4E), straight rhabds, 460–970 x 140–190 µm, cladomes, 225–400 µm per ray. Relatively rare straight oxeas, up to 4520–6460 x 65 –80 µm. Microscleres are finely acanthose oxyasters (Figs. 4G–H), 10 µm in diameter and abundant throughout the sponge, finely acanthose sanidasters (Figs. 4I –J), 13 µm in longest extension, rhabd is 1.5–2.5 µm in diameter, actins have inflated points due to a concentration of spines there and measure 1.8–2.7 x 0.5–0.7 µm. Finely acanthose plesiasters (Figs. 4K–L), 48–72 µm in diameter. Sanidasters and plesiasters are rare; the latter observed just below the cortex.

Discussion. The World Porifera Database lists 14 valid species of Ancorina and none are known to occur in the North Pacific Ocean. The geographically closest congener is Ancorina radix Marenzeller, 1889 which was originally described from the Mediterranean Sea but subsequently recorded from regions of the Northeast Atlantic as far north as eastern Greenland. A. radix was described to be nut-sized, without dichotriaenes, and with much shorter triaenes, described as “Stumpwinkler” and “Spitzwinkler” (p. 16),which are, according to the figure (pl. III, 6a–b), plagiotriaenes (rhabds, 980–2100 x 14–80 µm and clads, 70–238 x 28–40 µm) and longer oxeas (“Umspitzer”, 1980–4620 x 28–70 µm). It also differs considerably from Ancorina buldira n. sp. based on categories of microscleres, possessing two size categories of oxyasters (large 40–80 µm and small 10–18 µm), and possessing smaller sanidasters (10–80 x 2.5–5 µm) and plesiasters.

Etymology. Named after Buldir Island, the island near the locality where the holotype was collected.