Latrunculia (Latrunculia) hamanni Kelly, Reiswig & Samaai, sp. nov.

Latrunculia (Latrunculia) hamanni Kelly, Reiswig & Samaai sp. nov.

(Fig. 2 B, Fig. 5, 6, 16 L; Tables 2, 8, 9)

Latrunculia sp. undescribed, Na et al. 2010: 385.

Latrunculia n. sp. (dark purple brown hemisphere), Abbas et al. 2011: 2429‒2430; Fig. 8 B. Latrunculia (Biannulata) oparinae, Stone et al. 2011: 113, Fig. 1‒4; 141, 145 (not: Samaai & Krasokhin 2002).

Material examined. Holotype— RBCM 015-00480-001: 29 km SSE of Russian Bay, Umnak Island, eastern Aleutian Islands, 52.888° N, 168.253° W, 121 m, 30 May 2013, NOAA Fisheries, FV Ocean Explorer, Station-haul 5, Cruise 201301, collected by N. Laman. Paratypes— Eastern Aleutian Islands: RBCM 015-00481-001, RBCM 015-00481-002: 11 km west of Cape Kigushimkada, 53.118° N, 168.974° W, 265 m, 13 Jun 2012, NOAA Fisheries, FV Ocean Explorer, Station-haul 27, Cruise 201201, collected by B. Knoth; RBCM 015-00482-001: 8.5 km SSW of Herbert Island, Islands of Four Mountains, 52.648° N, 170.219° W, 235 m, 18 Jun 2012, NOAA Fisheries, FV Ocean Explorer, Station-haul 41, Cruise 201201, collected by B. Knoth. Central Aleutian Islands: 6.6 km SSW of Cape Tusik, Kanaga Island, Adak Strait, RBCM 015-00483-001: 51.622° N, 177.238° W, 150 m, 26 Jun 2004, NOAA Fisheries, RV Velero IV, Delta submersible dive transect 6199, Station 5E, collected by R.

Stone; RBCM 015-00484-001: 51.622° N, 177.239° W, 155 m, 2 Jul 2004, NOAA Fisheries, RV Velero IV, Station 5E, collected with a 6 m shrimp trawl. Other material. Aleutian Islands: RBCM 015-00485-001: 17.6 km N of Petrel Pt., Semisopochnoi Island, Petrel Bank, 52.185° N, 179.655° E, 117 m, Alaska Department of Fish & Game (United States), FV Ballyhoo, annual king crab survey, 22 Nov 2009, collected by R. Burt; NHMUK 2006.8.24.1: 17 km NNE of Adugak Island, Samalga Pass, 53.063° N, 169.087° W, 232 m, 12 Jun 2004, NOAA Fisheries, FV Gladiator, Station 279–48, Cruise 200401, Haul 25; NHMUK 2006.8.24.2: 10 km WNW of Uliaga Island, Islands of Four Mountains, 53.115° N, 169.914° W, 217 m, 13 Jun 2006, collected with bottom trawl on NOAA Fisheries annual groundfish stock assessment survey (featured in Na et al. 2010); NHMUK 2008.3.27.2: Little Tanaga Strait, 51.871° N, 176.266° W, 146 m, 28 Jun 2004, collected by R. Stone using submersible Delta launched from RV Velero IV; NMHUK 2011.2.11.4: 17.7 km west of Witchcraft Point, Kiska Island, 52.070° N, 177.247° E, 88 m, 28 Jul 2010, NOAA Fisheries, FV Sea Storm, Station-haul 173, Cruise 201001, collected by J. Sims.

Type location. Russian Bay, Umnak Island, eastern Aleutian Islands.

Distribution. North Pacific Ocean, from Kiska Island to Umnak Island in the Aleutian Islands, including Petrel Bank which extends into the Bering Sea.

Description. Hemispherical to spherical sponge (Fig. 5), about 16 cm diameter, by 4–5 cm thick, with short cylindrical oscules, 4–5 mm wide, elevated 2 mm high, much contracted in the preserved form, appearing taller than wide (Fig. 5 C–E). Numerous, small, raised, sucker-shaped areolate pore fields cover the surface in life (Fig. 5 A, B), collapsing into dimples in the preserved condition. Texture in life firm, surface leathery, difficult to tear, the interior is cavernous, fibrous, and stringy, collapsed in the preserved state. Colour in life is dark chocolate to purplish brown. Often attached to large, smooth pebbles (Fig. 5 E), cobbles or boulders.

Skeleton. Ectosome, a palisade of anisodiscorhabds above a layer of megascleres 350–500 µm thick; the megascleres are paratangential to the ectosome but tend towards vertical near the pore fields. Numerous anisodiscorhabds are scattered between the megascleres in the ectosome. Choanosome, a cavernous, wide-meshed reticulation of thick, loosely constructed tracts of megascleres, about 150–250 um wide (Fig. 6 A). Megascleres and microscleres are scattered throughout the choanosome between tracts.

Spicules. Megascleres (Fig. 6 B, Table 2), anisostyles, fusiform, slightly sinuous, head acanthose with retrovert spines, 492 (442–545) × 13 (8–15) µm.

Microscleres (Fig. 6 C–G, Table 2), anisodiscorhabds, manubrium composed of three spear-shaped sculpted spines (Fig. 6 G) with rows of tiny teeth that curve along the edges of the sculpted sections, emanating obliquely from the end of the shaft. The basal whorl, above the manubrium, consists of six thick, sharp, sculpted spines, ornamented with single spines and rows of tiny teeth, spines slant towards the manubrium. The median and subsidiary whorls are also composed of serrated, sculpted spines, approximately equal in diameter, 30 (23–35) µm. Shaft is lightly microspined. Apical whorl and apex are not clearly differentiated, forming a solid tuft of spines that are smooth and lightly serrated along sculpted sections (Fig. 6 F), 48 (40–55) µm long.

Substrate, depth range and ecology. Locally common in Alaskan waters; densities of up to 14 individuals per m2 were observed in the central Aleutian Islands (Stone et al. 2011). Grows on bedrock, pebbles, cobbles and boulders, on shelf and upper slope habitats, at depths between about 80 and 300 m in areas with relatively high currents. Sympatric with L. oparinae (Stone et al. 2011).

Etymology. Named for Mark T. Hamann, Professor of Pharmacognosy, Pharmacology and Biochemistry, University of Mississippi, for his contribution to sponge systematics through his diverse studies of marine natural products and sponge biochemistry.

Remarks. Latrunculia (L.) hamanni sp. nov. was first collected in 2004 but identified only as “ Latrunculia sp. undescribed” in a study that yielded two new brominated pyrroloiminoquinones, dihydrodiscorhabdin B and discorhabdin Y, along with six known pyrroloiminoquinone alkaloids (Na et al. 2010; NHMUK 2006.8.24.1–2). These compounds exhibited significant antiviral activity against hepatitis virus C, antimalarial activity against Plasmodium falciparum, and antimicrobial effects against several AIDS opportunistic pathogens. The species was collected again in 2006 and 2010, and in 2011 was discussed in the light of the Na et al. (2010) findings by Abbas et al. (2011: 2429‒2430, Fig. 8 B), but named only as “ Latrunculia n. sp. (dark purple brown hemisphere)”. The species was further highlighted in Stone’s et al. (2011) guide to the deep-water sponges of the Aleutian Island Archipelago as one of the three key species of Latrunculia in the region, along with L. velera and L. (L.) austini. It was, however, mistakenly identified as a “dark brown (dominant) colour morph” of L. oparinae (Stone et al. 2011: 113, species 93, Fig. 1–4; the only image of L. oparinae in Stone et al. (2011) is in Fig. 2 (left), yellowish green specimen, Stone et al. 2011: 113). All remaining sponge images illustrate L. (L.) hamanni sp. nov., and have been replicated in Fig. 5 here.

Latrunculia (L.) hamanni sp. nov. is easily distinguished from other species of Latrunculia in the North Pacific and other regions, by a combination of characters including the deep chocolate brown colouration, the discrete areolate pore fields, and anisodiscorhabds with a large undifferentiated apical whorl and apex that forms a solid tuft of spines. The species differs from L. (L.) austini which forms discrete, green spheres with large, apical oscules, and broad pore fields that almost obscure the exterior features. The megascleres of L. (L.) austini are about 130 µm longer than those of L. (L.) hamanni sp. nov., half the thickness, and they have smooth heads compared to those of L. (L.) hamanni sp. nov. The anisodiscorhabds of L. (L.) austini are about 7 µm longer and more slender than those of L. (L.) hamanni sp. nov., and the microscleres are slender with sculpted, denticulate, undulating, almost petalshaped whorls (see Fig. 4, Table 1). Those of L. (L.) hamanni sp. nov. have serrated, sculpted spines.

Latrunculia (L.) hamanni sp. nov. is sympatric with L. oparinae and L. velera, and can be differentiated on subtle differences in colour and morphology; L. oparinae is khaki green to light brown with a fibrous, cavernous morphology, and L. velera is dull light brown and club-shaped. The anisodiscorhabds of L. oparinae and L. velera are, however, quite different from those of L. (L.) hamanni sp. nov., forming the basis for establishment in this work of a new subgenus Latrunculia (Uniannulata) subgen. nov. (see Fig. 6).