Latrunculia (Biannulata) citharistae Vacelet, 1969

Samaai, Toufiek, Gibbons, Mark J. & Kelly, Michelle, 2006, Revision of the genus Latrunculia du Bocage, 1869 Porifera: Demospongiae: Latrunculiidae) with descriptions of new species from New Caledonia and the Northeastern Pacific (, Zootaxa 1127 (1), pp. 1-71 : 49-52

Latrunculia (Biannulata) citharistae Vacelet, 1969

( Figs 1Q, 5E , 7 , 8A; Tables 2 & 3)

Latrunculia citharistae Vacelet, 1969: 195

Holotype material. Holotype MNHN­JV­68­14 Latrunculia citharistae ( Vacelet, 1969: 195) .

Other material examined. HBOM 10­VI­91­4­007 (cross ref. TS 44), Canary Islands, Hierro; S. Coast, 3.75 NMI 120 DEG to Puerto Naos, depth 147 m, collected by HBOI. HBOM 13­ VI­91­4­012 (TS 45), Canary Islands, Tenerife; W. coast, 2.03 NMI 120 Deg to San Juan, depth 477 fathoms, collected by HBOI. HBOM 2­VI­91­4­007 (Ts 42), Ilheus Selvagem, Selvagem Penuena; S. coast, 1.32 NMI 350 Deg to Pt Sul, de Ilheu, depth 232 m, collected by Harbour Branch, 1996.

Description. Massive, spherical, 5 x 4 x 3 cm in diameter. Other specimens are small, semispherical, sponges up to 2 cm high and 2 cm wide ( Fig. 8A). Surface smooth with numerous cylindrical­shaped oscules; some at the apex larger than the rest, 2 mm wide and 4 mm high. The remainder is volcano­shaped mammiform processes, each with a distinct small opening at the top, 2 mm high, 0.1 mm wide. Ectosome thin and easily separable from underlying choanosome. Texture firm, resilient, soft but leathery. Colour in life is dark green; colour in preservative, choanosome dark brown and ectosome light brown (from Vacelet, 1969). Vacelet (1969) described the fresh holotype to have a dark brown colour and also possessing osculae and mammiform areolate porefields. Additionally, Vacelet (1969) noted that the holotype contained reddish embryos, 500 µm diameter.

Skeleton. The choanosomal skeleton consists of a loose, ill­defined irregular polygonal­meshed reticulation formed by wispy tracts of styles, with no distinction between the primary and secondary tracts ( Fig. 5E ). The tracts range in width from 45–50 m in thickness, and may form meshes that are 200 m wide. Towards the surface the tracts become more vertically arranged. Interstitial spicules absent in choanosome. The surface of the ectosome is lined with an erect layer of non­interlocking anisodiscorhabds. Beneath the discorhabds in the ectosome is a thin tangential­paratangential layer of interlocking megascleres, approximately 75 m wide.

Spicules. Megascleres: styles are smooth, thin, centrally thickest, hastately pointed with a slight sinuous curve, 356 (345–382) x 5 (5) m, n=20; Holotype 310–460 x 4–6 m. Microscleres ( Fig. 1Q): anisodiscorhabds, possessing identical median and subsidiary whorls symmetrically arranged around the shaft. The manubrium is a minute spinose base consisting of two or three whorls of spines, followed immediately by a smooth slender cylindrical shaft 12 m long and 2.3 m wide. The median and subsidiary whorls are circular, flat, slanted slightly in opposite directions and similar in diameter, 19 m. Each whorl is deeply notched and composed of eight spines, divided amongst three groups, which give three sets for each of them. The spines of the apical whorl are slanted slightly upwards, and divided, ending in a crown­like tuft of dichotomous spines. Acanthodiscorhabd length, 45 (41–48) x 5 (5) m, n=20.

Substratum, depth range and ecology. Stalk of sea whip; dredge from slope/ rock rubble seems to very common; Specimen HBOM 2­VI­91­4­007 was dredged from mud slopes and was associated with other sponges. Depth range: 147–232 m

Geographic distribution ( Fig. 7 ). Canary Islands, Mediterranean Sea.

Remarks. Hinde and Holmes (1892) (P. 219, FIG. 39) recorded a fossil anisodiscorhabd structure from the Oamaru Diatomite, New Zealand of a species that occurred during the late Eocene­early Oligocene era. These authors also suggested that this form was a modification of a common plane, which ultimately gave rise to the phyllamentous­type discorhabd. The discorhabd structure of the extant L. (B.) citharistae conforms very closely in detail to the illustration and description of the fossil spicule given by Hinde and Holmes (1892) and could be considered as a recent flesh spicule of this type. The discorhabd structure of the extant Latrunculia citharistae differs however from the fossil spicule in that the spines of the apical whorl are slanted slightly upwards, as appose to forming a distinctive crown­like structure as in the fossil species ( Hinde and Holmes 1892; Latrunculia sp. , PL. XI, FIGS 39, 40). Apart from this L. citharistae the spicule also differ in length, being much smaller in size than what is recorded for the fossil species (75 µm). It is difficult to say whether the fossil acanthodiscorhabds are homologous to that found in the extant species, but it does suggest that several species of “latrunculids” with this form must have coexisted at the source of this assemblage (See also Wiedenmayer 1994).

The occurrence of this species in both the North Atlantic and the Mediterranean Sea, and its affinities with New Zealand (same flesh spicular structure) probably suggest a Tethyan origin of this species complex. At present L. citharistae is here restricted to the deep­water North Atlantic and Mediterranean regions and has not been recorded in the southern hemisphere ( Table 2).

Structurally the anisodiscorhabd differs from the variety of forms presently found within the genus, in that it posses a slender cylindrical shaft with the two lobate whorls in the middle portion of the shaft. Its relationship to the other species with flesh spicules is one of assumption and could only be resolved with additional data.

Figures

FIGURE 5. Photomicrographs of choanosomal architectures: A. Latrunculia ikematsui Tanita 1968; B. Latrunculia oxydiscorhabda Alvarez et al. 2002; C. Latrunculia triverticillata Alvarez et al. 2002; D. Latrunculia austini sp. nov.; E. Latrunculia citharistae Vacelet 1969; F. Latrunculia purpurea Carter 1881.

FIGURE 7. Worldwide distributions of Latrunculia (Biannulata) species. Distributions of A) Latrunculia spinispiraefera Brøndsted, B) Latrunculia citharistae Vacelet, C) Latrunculia purpurea Carter, D) Latrunculia oparinae Samaai and Krasokhin; E) Latrunculia lunaviridis Samaai and Kelly; F) Latrunculia microacanthoxea Samaai and Kelly; G) Latrunculia kaakaariki Alvarez et al.; H) Latrunculia duckworthi Alvarez et al.; I) Latrunculia procumbens Alvarez et al.; J) Latrunculia wellingtonensis Alvarez et al., 2002; K) Latrunculia kaikoura Alvarez et al.; L) Latrunculia millerae Alvarez et al.; M). Latrunculia austini sp. nov.