Latrunculia (Latrunculia) austini Samaai, Kelly & Gibbons 2006

Latrunculia (Latrunculia) austini Samaai, Kelly & Gibbons, 2006 (Fig. 2 A, 3, 4, 16K; Tables 1, 8, 9) Latrunculia (Biannulata) austini Samaai, Kelly & Gibbons, 2006: 46; Fig. 1 O, 3H, 5D, 7; Table 2, 3. Latrunculia austini, Abbas et al. 2011: 2429 ‒2430; Fig. 8 B. Latrunculia sp. (undescribed), Stone et al. 2011: 115, Fig. 1‒2; 141, 145. Sceptrella sp. nov. (chocolate puffball sponge), Lamb & Hanby 2005: 67. Material examined. Type material. Holotype — RBCM 982-62-1: Sutton Island, Jervis Inlet, British Columbia, 49.758° N, 123.927° W, 30 m. British Columbia, Canada: RBCM 014-00091-001: Learmonth Bank, Dixon Entrance, 54.367° N, 132.826° W, 384 m, 3 Jul 2008, collected by S. Lees and J. Pegg from Canadian Coast Guard ship JP Tully, Canadian Scientific Submersible Facility ROPOS ROV Dive 1153-0009b; RBCM 015-00475-001: East of Dundas Island, 54.590° N, 130.962° W, 62 m, 19 May 2009, collected by J. Pegg from Canadian Coast Guard ship JP Tully, Canadian Scientific Submersible Facility ROPOS ROV (Pac2009 Dive 13); RBCM 014- 00118-001 (KML acc 1148): Upwood Point, Texada Island, 49.483° N, 124.117° W, 21 m, 10 Sep 2001, collected by N. McDaniel; RBCM 014-00119-001 (KML Stn 190/83): Truro Island, Portland Canal, 54.732° N, 130.388° W, 91 m, 30 Oct 1983. North Washington State, United States of America: RBCM 015-00476-001: Olympic Coast National Marine Sanctuary, Survey Site 36, 48.133° N, 125.076° W, 163 m, 10 Jul 2008, collected by M. S. Brancato from Canadian Coast Guard ship JP Tully, Canadian Scientific Submersible Facility ROPOS ROV Dive 1159; RBCM 015-00478-001: Olympic Coast National Marine Sanctuary, Survey Site 36, 48.131° N, 125.083° W, 206 m, 10 Jul 2008, collected by M. S. Brancato from Canadian Coast Guard ship JP Tully, Canadian Scientific Submersible Facility ROPOS ROV Dive 1159. Gulf of Alaska, United States of America: NHMUK 2008.3.27.3: 28 km west of Cape Ommaney, Baranof Island, 56.186° N, 135.108° W, 102 m, 17 Aug 2005, collected by R. Stone with the submersible Delta from RV Velero IV (figured in Stone et al. 2011), spicules only; RBCM 015-00479-001, RBCM 015-00479-002: Shutter Ridge, 28 km west of Cape Ommaney, Baranof Island, 56.198° N, 135.102° W, 88 m, 15 Aug 2013, collected by R. Stone with ROV deployed from the FV Alaska Provider; RBCM 015-00479-003: Shutter Ridge, 28 km west of Cape Ommaney, Baranof Island, 56.198° N, 135.103° W, 87 m, 15 Aug 2013, collected by R. Stone with ROV deployed from the FV Alaska Provider; RBCM 015-00479-004: Shutter Ridge, 28 km west of Cape Ommaney, Baranof Island, 56.197° N, 135.102° W, 106 m, 15 Aug 2013, collected by R. Stone with ROV deployed from the FV Alaska Provider. Other location records. British Columbia, Canada: Sonora Point, Sonora Island, between Dixon Entrance and Juan de Fuca, 50.427° N, 125.306° W, 155–159 m, 24 Mar 2007, collected by J. Pegg, Fisheries and Oceans Canada. North Washington State, United States of America: Olympic Coast National Marine Sanctuary, 48.125° N, 125.371° W, 115 m, 27 May 2006, collected by M. S. Brancato from Canadian Coast Guard ship JP Tully, Canadian Scientific Submersible Facility ROPOS ROV Dive 953; Olympic Coast National Marine Sanctuary, 48.302° N, 124.937° W, 243 m, 0 1 Jun 2006, collected by M. S. Brancato from Canadian Coast Guard ship JP Tully, Canadian Scientific Submersible Facility ROPOS ROV Dive 958‒131; Olympic Coast National Marine Sanctuary, 48.169° N, 125.370° W, 114 m, 11 Jul 2008, collected by M. S. Brancato from Canadian Coast Guard ship JP Tully, Canadian Scientific Submersible Facility ROPOS ROV 1160‒0031; Olympic Coast National Marine Sanctuary, Survey Site 17, 48.116° N, 125.371° W, 13 Jul 2008, collected by M. S. Brancato from Canadian Coast Guard ship JP Tully, Canadian Scientific Submersible Facility ROPOS ROV Dive 1163. Type location. Jervis Inlet, British Columbia, 30 m. Distribution. Continental shelf and slope off eastern Gulf of Alaska, south along outer coast of British Columbia including Queen Charlotte Sound, to British Columbia –Washington State border. Description. Small spherical to block-shaped sponge (Fig. 3), typically about 5–8 cm diameter, but can reach up to 12 cm diameter, found often in large groups (Fig. 3 G, I, K). Surface distinctive with small, circular, cratershaped pore fields (e.g. Fig. 3 F, I, J), or pore fields that cover large sections of the surface (e.g. Fig. 3 A, B, G, H). Skeletal network visible through pore fields in life. One to five large oscules appear prominently on the apex of specimens; these are either flush or raised (Fig. 3 J). Texture very soft and compressible, somewhat slimy in life; surface features collapse in preservation. Colour in life is khaki to emerald green in deeper waters. The holotype (Fig. 3 A), and other shallow-water British Columbian specimens are brown (Fig. 3 B), colour in preservative is dark brown. Lamb & Hanby (2005) noted that their specimen was a turquoise green underwater but chocolatecoloured under artificial light. Skeleton. Ectosome a palisade of vertically arranged anisodiscorhabds, below which is a thin paratangential layer of megascleres; ectosome varies in thickness but averages about 100 µm. Choanosome, a polygonal reticulation of wispy tracts of anisostyles, tracts undifferentiated into primary and secondary structures, sometimes forming a loose, laddered structure within the deep choanosome. Tracts about 100 µm wide, and meshes variable, 100–500 µm wide. Megascleres plumose below the sub-ectosome. Choanosome cavernous near oscules and in the sub-ectosome. Spicules. Megascleres (Fig. 4 F, Table 1), anisostyles, fusiform, with smooth heads, rarely malformed and polytylote, slightly sinuous, often slightly bent in the upper third, 363 (246–428) × 7 (5–12) µm. Microscleres (Fig. 4 A–E, Table 1), anisodiscorhabds, manubrium completely separate from basal whorl in about 90% of spicules (Fig. 4 E, O–R), highly variable and quite close to basal whorl in about 8% of spicules (Fig. 4 A–C, K–N), basal whorl and manubrium indistinguishable in about 2% of spicules (Fig. 4 D, I–J). Median and subsidiary whorls are composed of undulate petals and/or sculpted spines with denticulate margins, manubrium and basal whorl are spines that appear sculpted with rows of tiny spines. The apical whorl and apex slant towards vertical and are formed from fused undulating petals with denticulate margins forming overall, a beautiful roseshaped crown, 54 (45–65) × 27 (20–37) µm. Substrate, depth range and ecology. Locally abundant in Alaska off the continental shelf off Cape Ommaney, Baranof Island, eastern Gulf of Alaska (Stone et al. 2011). Grows on bedrock and boulders in Alaskan shelf habitats, in the subduction zone between 69 and 210 m, on part of the basement rock complex of a tectoniostratigraphic terrane of the Pacific Plate that has docked with Alaska (H. Gary Greene, Moss Landing Marine Laboratories, pers. comm.). Relatively common in the shallow inlets of Queen Charlotte Sound and coastal inlets of the British Columbia Coast, down to about 30 m, but also found in deeper waters (110–384 m) off the coast. In Alaska, can be found in association with the homosclerophorid Plakina atka Lehnert et al. 2005. Often found in small groups of dozens of individuals, and can be locally abundant. Remarks. When L. (L.) austini was first described, it was considered to be rare (Samaai et al. 2006) as it was only known from the type location. Samaai et al. (2006) placed L. austini within the newly established subgenus Latrunculia (Biannulata), a decision that was considered to be erroneous by Samaai et al. (2012), who relegated L. austini and two other species to incertae sedis. The 2006 description was based upon a single specimen, the holotype, which had a high percentage of anisodiscorhabds with malformations (See Fig. 4 A–D), and a relatively high number of microscleres in which the manubrium and the basal whorl were indistinguishable (see Fig. 4 H–R); fusion of these two structures is diagnostic for species of subgenus L. (Biannulata). Examination of numerous new specimens in this study reveal that the majority of microscleres have a fully differentiated manubrium and basal whorl (see Fig. 4 E, O–R), and that because of this, assignment to L. (L.) is the most parsimonious solution. Specimen Anisostyles Anisodiscorhabds British Columbia, Canada RBCM 982-62-1 Holotype 376 (335‒402) 58 (51‒64) RBCM 014-00091-001 396 (327‒428) × 9 (7‒11) 55 (51‒63) × 28 (23‒33) RBCM 015-00475-001 355 (304‒392) × 5 (8‒9) 51 (48‒59) × 25 (20‒30) RBCM 014-00118-001 329 (246‒366) × 7 (5‒8) 54 (48‒59) × 30 (24‒36) RBCM 014-00119-001 350 (282‒389) × 7 (5‒9) 56 (49‒65) × 28 (23‒32) North Washington State, United States of America RBCM 015-00476-001 379 (356–399) × 8 (7‒12) 53 (46‒59) × 34 (27‒37) RBCM 015-00478-001 357 (309‒390) × 8 (6‒10) 51 (45‒57) × 27 (22‒31) Gulf of Alaska, United States of America NHMUK 2008.3.27.3 369 (350‒385) × 8 (7‒10) 56 (53‒60) × 26 (21‒28) RBCM 015-00479-001 354 (350‒375) × 6 (5‒8) 50 (45‒56) × 23 (20‒25) RBCM 015-00479-002 363 (342‒380) × 7 (6‒8) 51 (48‒53) × 24 (23‒25) Hajdu et al. (2013) commented on the same phenomenon in relation to their four new species of Latrunculia (L.) from the Chilean fiords. These authors considered that, despite the lack of a clear space between the manubrium and basal whorl spines in some of the anisodiscorhabds, the difference in orientation of the spines, with the basal whorl slanting towards the apex and the manubrium slanting towards the base, indicated a greater affinity with species in L. (L.) than with species in L. (Biannulata). Latrunculia (L.) austini is moderately variable in terms of morphology, depth distribution and latitude; there is a colour difference between the shallow-water holotype (brown) and offshore (green) specimens, and a small proportion of the microscleres in some specimens are malformed. The species ranges in distribution from the eastern Gulf of Alaska, east and south to the n

Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.