Latrunculia (Uniannulata) oparinae Samaai & Krasokhin, 2002

Kelly, Michelle, Sim-Smith, Carina, Stone, Robert, Reiswig, Toufiek Samaai Henry & Austin, William, 2016, New taxa and arrangements within the family Latrunculiidae (Demospongiae, Poecilosclerida), Zootaxa 4121 (1), pp. 1-48 : 17-20

Latrunculia (Uniannulata) oparinae Samaai & Krasokhin, 2002 subgen. nov., comb. nov.

( Fig. 2 B, 8, 16AG; Tables 4 , 8 , 9 )

Latrunculia oparinae Samaai & Krasokhin, 2002: 95 –101; Fig. 1 A–G, 2.

Latrunculia (Biannulata) oparinae, Samaai et al. 2006: 54 ; Fig. 1 S, 6N, 7, 8C, 9A; Table 2 , 3 . Latrunculia oparinae, Abbas et al. 2011: 2429 ‒2430, Fig. 8 A.

Not Latrunculia (Biannulata) oparinae, Stone et al. 2011: 113 , Fig. 1–4 ; 141, 145. Latrunculia cf. tricincta, Austin et al. http://www.mareco.org/spongepage/ Latrunculia %20sp%20cf%20 tricincta .htm (not: Hentschel 1929).

Material Examined. Central Aleutian Islands: NHMUK 2011.2.11.1: south Amchitka Pass, 8.5 km WNW of Unalga Island, Delarof Islands, 51.594° N, 179.180° W, 223 m, 24 Jul 2010, NOAA Fisheries, FV Sea Storm, Station-haul 160, Cruise 201001, collected by J. Sims; RBCM 015-00488-001: 20.9 km S of SW Amlia Island, 51.859° N, 173.910° W, 195 m, 6 Jul 2004, NOAA Fisheries, RV Velero IV, Delta submersible Dive 6222, Station 2A, collected by H. Lehnert; RBCM 015-00489-001: 0.5 km N of SW Kasotochi Island, 52.174° N, 175.615° W, 112 m, 7 Jul 2004, NOAA Fisheries, RV Velero IV, Delta submersible Dive 6227, Station Kasotochi, collected by D. Carlile; RBCM 015-00484-002: 6.6 km SSW of Cape Tusik, Kanaga Island, Adak Strait, 51.622° N, 177.239° W, 155 m, 2 Jul 2004, NOAA Fisheries, RV Vel ero IV, Station 5E, collected by R. Stone with a 6 m shrimp trawl (4 specimens); NHMUK 2008.3.27.1: same locality data as above; RBCM 015-00490-003: 25.2 km WNW of Amtgnak Island, Delarof Islands, Amchitka Pass, 51.333° N, 179.503° W, 175 m, 3 Aug 2004, NOAA Fisheries, RV Roger Revelle, ROV Jason II Dive 102, Station 14, collected by R. Stone. Eastern Aleutian Islands: NHMUK 2006.8.24.3: 17 km NNE of Adugak Island, Samalga Pass, Aleutian Islands, 53.063° N, 169.087° W, 232 m, 12 Apr 2004, NOAA Fisheries, FV Gladiator , Station 279-48, Cruise 200401, Haul 25; RBCM 015-00487-001: 8.5 km SSW of Herbert Island, Islands of Four Mountains, 52.648° N, 170.052° W, 235 m, 18 Jun 2012, NOAA Fisheries, FV Ocean Explorer, Station-haul 41, Cruise 201201, collected by B. Knoth.

Type location. Kurile Islands, Sea of Okhotsk, Russia.

Distribution. Kurile Islands, Sea of Okhotsk, Russia to the Islands of Four Mountains, eastern Aleutian Islands, Alaska.

Description. Small globular to spherical or block-shaped sponge, width 47 (25–65) mm × height 34 (20–50) mm × thickness 39 (20–60) mm, n = 10; surface covered with distinctive trumpet-shaped areolate pore fields, and long, broad, cylindrical apical oscular tubes or long tapered oscular tubes on the periphery of the sponge ( Fig. 8 A– E). Aquiferous structures on some specimens are short and squat. Texture firm, interior markedly fibrous and stringy, almost honeycombed, difficult to tear. Colour in life is khaki green to light greenish brown, darkening to oak brown in preservative. Often attached to pebbles or bivalve shells in life.

Skeleton. Ectosome, a palisade of anisodiscorhabds above a sub-ectosomal paratangential layer of megascleres, 475–550 µm thick ( Fig. 8 F); this layer tends towards vertical near the pore fields. Choanosome, extremely cavernous and stringy with thick, compact tracts of megascleres 500–600 µm wide, but many are up to 800 µm wide. Gaps between tracts are well over several thousand µm wide. Microscleres are scattered between the megascleres in the ectosome and throughout the choanosome.

Spicules. Megascleres ( Fig. 8 G; Table 4 ), anisostyles, centrally thickened and slightly sinuous, head acanthose with conical and retrovert spines, 507 (400–610) × 15 (11–19) µm.

Microscleres ( Fig. 8 H–L; Table 4 ), anisodiscorhabds, manubrium composed of five chisel-shaped doublet projections, with a small number of scattered spines, emanating obliquely from the end of the shaft, basal whorl above the manubrium consists of another five sets of chisel-shaped, more distinctly doublet projections, ornamented with small spines ( Fig. 8 L). The median whorl is composed of horizontal, micro-spined paddles with denticulate margins, 31 (28–38) µm. Subsidiary, apical whorl and apex are only partially differentiated ( Fig. 8 K, right), forming a solid tuft of micro-spined spines with denticulate margins, 46 (35–53) µm long.

Substrate, depth range and ecology. Prior to this work L. (U.) oparinae was known only from the Kurile Islands, where it was found on a gravel and sand seafloor between 127–238 m ( Samaai & Krasokhin 2002; Samaai et al. 2006). In the Aleutian Islands the species is quite common at depths between 79 and 288 m ( Stone et al. 2011). The species is sympatric with L. (L.) hamanni sp. nov. ( Stone et al. 2011), and grows directly on bedrock, pebbles, cobbles and boulders, in areas of relatively flat seafloor with moderate to high currents. Latrunculia (U.) oparinae is discrete and easily recognisable, having a globular shape with columnar aquiferous structures, and being a characteristic olive to khaki green in colour.

Remarks. Latrunculia (Uniannulata) oparinae and L. (L.) hamanni sp. nov. are sympatric species, separated in the field primarily on colouration, and morphology of the aquiferous structures; L. (U.) oparinae is khaki green with tall thin elevated pore fields and oscules, while L. (L.) hamanni sp. nov. is dark purplish brown and has short, sucker-shaped pore fields and oscules (see Fig. 8 B). Both species have a firm, fibrous, stringy texture. The key taxonomic point of difference, however, is the morphology of the anisodiscorhabds; in L. (U.) oparinae the subsidiary whorl does not appear independently above the median whorl as it does in L. (L.) hamanni sp. nov., and the whorls of the anisodiscorhabds in L. (U.) oparinae are composed of broad paddles, or petals with serrated edges, while those of L. (L.) hamanni sp. nov. are almost entirely composed of sculpted spines. Furthermore, the apical whorl and apex in the anisodiscorhabds of L. (U.) oparinae form crown-like rings of double serrated paddles that frequently occur in pairs (see Fig. 8 K, L), while the spines of the apex and apical whorl of L. (L.) hamanni sp. nov. form a solid undifferentiated tuft ( Fig. 5 F). The megascleres of L. (U.) oparinae are about 20 µm longer than those of L. (L.) hamanni sp. nov. Latrunculia (U.) oparinae is also similar in colouration to L. (L.) austini but the latter species is very different morphologically and has not been found, to date, west of the eastern Gulf of Alaska.

Figures

FIGURE 1. Comparison of microsclere morphology in family Latrunculiidae (not to scale): A. Anisodiscorhabd form in subgenus Latrunculia (Latrunculia) du Bocage, 1869 (type species L. (L.) bocagei Ridley & Dendy, 1886), showing the six substructures that characterise the anisodiscorhabds, whether differentiated or undifferentiated: m = manubrium, bw = basal whorl, mw = median whorl, sw = subsidiary whorl, aw = apical whorl, a = apex; B. Anisodiscorhabd form in subgenus Latrunculia (Biannulata) Samaai, Gibbons & Kelly, 2006 (type species L. (B.) kaakaariki Alvarez et al., 2002); C. Anisodiscorhabd form in subgenus Latrunculia (Uniannulata) subgen. nov. (type species L. (U.) oparinae Samaai & Krasokhin, 2002); D. Isospinodiscorhabd in genus Cyclacanthia Samaai, Govender & Kelly, 2004 (type species C. bellae (Samaai, Gibbons, Kelly & Davies-Coleman, 2003); E. Isochiadiscorhabd in genus Tsitsikamma Samaai & Kelly, 2002 (type species T. favus Samaai & Kelly, 2002); F. Anisodiscorhabd and amphiclad sceptre in genus Sceptrella Schmidt, 1870 (type species Sceptrella regalis Schmidt, 1870); G. Short anisodiscorhabd and long anisoconicorhabd in genus Latrunclava gen. nov. (type species L. imago gen. et sp. nov.); H. Anisodiscorhabd in genus Bomba gen. nov. (type species B. endeavourensis gen. et sp. nov.). Fig. 1 A, B, D modified and reproduced from Samaai et al. (2006), Samaai et al. (2004) and Samaai et al. (2003), respectively, with permission from Zootaxa (Magnolia Press). Fig. 1 E, F modified with permission from T. Samaai.

FIGURE 2. Distribution of North Pacific Latrunculiidae species: A. Gulf of Alaska, U. S. A and British Columbia, Canada; B. Central Aleutian Islands and Gulf of Alaska, U. S. A. Locality data for the four Kurile Island specimens of Latrunculia (Uniannulata) oparinae subgen. nov. taken from Samaai & Krasokhin (2002) and Samaai et al. (2006). L = Latrunculia, B = Bomba gen. nov.

FIGURE 5. Latrunculia (Latrunculia) hamanni sp. nov.: A. NHMUK 2008.3. 27.2, Aleutian Islands, 146 m, in situ; B. Paratype RBCM 015 - 00483 - 001, Kanaga Island, central Aleutian Islands, 150 m, in situ, with L. oparinae (left, green specimen); C. Paratype RBCM 015 - 00483 - 001, preserved specimen; D. NMHUK 2011.2. 11.4, Kiska Island, western Aleutian Islands, 88 m, deck photo; E. Paratype RBCM 015 - 00481 - 002, Umnak Island, eastern Aleutian Islands, 265 m, preserved specimen. Scale bar for all images 5 cm. Fig. 5 A – C reproduced with permission from Stone et al. (2011). Fig. 5 D reproduced with permission from James Sims, image taken aboard NOAA Fisheries FV Sea Storm. Fig. 5 E by Robert Stone.

FIGURE 8. Morphology, megascleres and microscleres of Latrunculia (Uniannulata) oparinae Samaai & Krasokhin, 2002 subgen. nov. comb. nov.: A. RBCM 015 - 00489 - 001, central Aleutian Islands, in situ; B. Specimen on left (green) in situ with L (L.) hamanni sp. nov. (right, brown specimen), Kanaga Island, central Aleutian Islands, 150 m, in situ; C. NHMUK 2011.2. 11.1, specimen on deck; D. RBCM 015 - 00487 - 001, scale = 1 cm; E. NHMUK 2006.8. 24.3, specimen on deck; F. Histological section showing palisade of anisodiscorhabds in outermost ectosome, a paratangential layer of megascleres below palisade, and cavernous choanosome below, scale = 200 µm; G. Acanthose head of anisostyle with retrovert and conical spines on apex (from RBCM 015 - 00490 - 003), scale = 20 µm; H. Typical anisodiscorhabd (from RBCM 015 - 00490 - 003), scale = 20 µm; I. Typical anisodiscorhabd (from NHMUK 2008.3.27.1), scale = 20 µm; J. Typical anisodiscorhabd (from NHMUK 2006.8.24.3), scale = 20 µm; K. Anisodiscorhabd manubrium and basal whorl (left) and apical whorl and apex (right) (from RBCM 015 - 00490 - 003), scale = 20 µm; L. Base of anisodiscorhabd showing manubrium and basal whorl (from NHMUK 2006.8.24.3), scale = 20 µm; M. Protorhabd (from RBCM 015 - 00490 - 003), scale = 20 µm; N. Immature anisodiscorhabds (from NHMUK 2006.8.24.3), scale = 20 µm.

Tables

TABLE 4. Spicule dimensions (µm) of Latrunculia (Uniannulata) oparinae Samaai & Krasokhin, 2002 subgen. nov.

Specimen	Anisostyles	Anisodiscorhabds
ZMA Por. 10780 Holotype	435 (400‒464) × 16	40 (35‒44) × 28
NHMUK 2006.8.24.3	510 (495‒532) × 14 (12‒16)	46 (45‒48) × 33 (28‒38)
NHMUK 2011.2.11.1	500 (479‒533) × 14 (11‒16)	47 (45‒50) × 29 (28‒33)
RBCM 015-00487-001	535 (480‒590) × 16 (13‒18)	48 (45‒53) × 31 (28‒33)
RBCM 015-00489-001	550 (481‒610) × 14 (13‒18)	48 (45‒50) × 33 (30‒38)
RBCM 015-00490-003	510 (450‒560) × 16 (15‒19)	45 (40‒48) × 32 (30‒33)