Latrunclava imago Kelly, Reiswig & Samaai

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 : 34-36

Latrunclava imago Kelly, Reiswig & Samaai gen. et sp. nov.

( Fig. 1 G, 2B, 13; Tables 7 , 8 , 9 )

Material examined. Holotype— RBCM 150-00490-001: 25.2 km WNW of Amatignak Island, Delarof Islands, Amchitka Pass, central Aleutian Islands, 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. Paratype— RBCM 015-00490-002: same locality data.

Type location. Amchitka Pass, central Aleutian Islands.

Distribution. Central Aleutian Islands.

Description. Spherical to sub-spherical sponge, about 5 cm high and 4 cm thick, with thin, conical oscules, around 2 mm wide at the tip, up to 7 mm high ( Fig. 13 A). Sponge dark, rich brown, wrinkled and much contracted in the preserved state. Texture soft and compressible, the interior is cavernous, fibrous, and stringy.

Skeleton. A single layer of anisodiscorhabds forms a palisade in the ectosome, below which is a paratangential layer of megascleres, about 400 µm thick, becoming vertical near the pore fields. Numerous anisodiscorhabds and the occasional anisoconicorhabd are scattered between the subectosomal paratangential layer. The choanosomal architecture consists of wispy tracts of styles that form a very wide-meshed irregular reticulation. Numerous anisodiscorhabds, megascleres and the occasional anisoconicorhabd are scattered throughout the choanosome between tracts.

Spicules. Megascleres ( Fig. 13 D; Table 7 ), anisostyles, head spined retrovertly (spines face away from head along shaft), often very slightly sinuous, 543 (453–632) × 11 (9–15) µm.

Microscleres ( Fig. 13 E–I; Table 7 ), anisodiscorhabds, basal whorl comprises a ring of relatively large, simple spines that are sparsely acanthose and point slightly downwards. A manubrium spine present in the great majority of spicules ( Fig. 13 E, G, H). Median whorl a horizontal ring of large, sparsely acanthose spines. Apical whorl a ring of obliquely upward pointing spines that are rarely acanthose. Apex absent, 42 (38–48) × 29 (24–34) µm.

Anisoconicorhabds ( Fig. 13 B) in with basal whorl and manubrium of 2–3 obliquely projecting blunt spines, apical whorl and apex of spines, with an extended shaft between, covered in large spines, sometimes curved, projecting horizontally, spines and shaft are lightly acanthose. Three size categories: 1) short, squat and heavily spined ( Fig. 12 B, left), 92 (60–110) × 12 (10–15) µm; 2) medium length, moderately heavily spined ( Fig. 12 B, middle), 147 (120–160 × 20 (18–22) µm; 3) long, lightly spined on middle of shaft ( Fig. 12 B, right), 197 (170–240) × 23 (20–29) µm.

Substrate, depth range and ecology. Grows on cobbles and boulders on shelf and upper slope habitats, at a depth of 179 m in areas experiencing moderate to high currents; sympatric with L. oparinae .

Etymology. Named for the ‘echo’ of the new genus Latrunclava in the North Pacific, first recorded from spicules from the Late Eocene in the region of Zealandia that formed the Oamaru Diatomite ( imago , echo; L.).

Remarks. The discovery of sponges that contained a form of ‘sceptre’ in addition to normal anisodiscorhabds, superficially similar to those of Sceptrella regalis Schmidt, 1870 , and S. insignis Topsent, 1890 , came as a great surprise because Sceptrella is only known to date from the Atlantic Ocean region, including the Mediterranean and Gulf of Mexico. The anisoconicorhabd sceptres of Latrunclava imago subgen. et sp. nov. are quite different in that they are inequiended, with manubrium and basal whorl substructures that resembles those in the anisodiscorhabds of L. (Uniannulata) subgen. nov., in particular. The possession of three size categories of these anisoconicorhabds in Latrunclava imago subgen. et sp. nov. clearly differentiates this species from all other Latrunculiidae .

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 12. Morphology, megascleres and microscleres of Bomba tricincta (Hentschel, 1929) gen. nov., comb. nov.: A. Illustration of holotype ZMB Por 7851 from Northern Norway, 198 m (from Hentschel (1929, Pl. 12, Fig. 3); B. Large, thick tracts of megascleres, scale = 500 µm; C. Anisostyle, slightly sinuous, scale = 100 µm; D. Smooth proximal tip of anisostyle, scale = 100 µm; E. Smooth distal tip of anisostyle, scale = 100 µm; F. Range of anisodiscorhabds, scale = 50 µm; G. Range of protorhabds from earliest to later stages showing gradual development of the three whorls, scale = 50 µm. All images taken from microscope slide of holotype.

FIGURE 13. Morphology, megascleres and microscleres of Latrunclava imago gen. et sp. nov.: A. Latrunclava imago gen. et sp. nov., preserved holotype RBCM 150 - 00490 - 001, central Aleutian Islands, 175 m, scale = 1 cm; B. Range of anisoconicorhabds, scale = 50 µm; C. Microfossil anisodiscorhabds of Latrunculia oamaruensis Hinde & Holmes, 1892 (from Hinde & Holmes, 1892: 218, Pl. 11, Fig. 34, 35), scale = 50 µm; D. Head of anisostyle, acanthose with retrovert spines, scale = 20 µm; E. Typical anisodiscorhabds with manubrium, scale = 20 µm; F. Anisodiscorhabd lacking a manubrium, scale = 20 µm; G. Protorhabds showing presence of budding manubrium, scale = 20 µm; H. Basal portion of anisodiscorhabd showing manubrium and basal whorl, scale = 20 µm; I. Apical whorl (apex absent), scale = 20 µm.

Tables

TABLE 7. Spicule dimensions (µm) of Latrunclava imago gen. et sp. nov.

Specimen	Anisostyles	Anisodiscorhabds	Anisoconicorhabds
RBCM 150-00490-001 Holotype	543 (499–594) × 11 (9–13)	42 (38–48) × 29 (24–34)	1) 89 (60–110) × 13 (12–15) 2) 151 (120–160) × 20 (18–20) 3) 195 (170–230) × 21 (20–25)
RBCM 015-00490-002 Paratype	542 (453–632) × 11 (9–15)	42 (38–47) × 30 (25–33)	1) 95 (80–100) × 11 (10–15) 2) 142 (130–150) × 20 (18–22) 3) 199 (170–240) × 25 (20–29)