Latrunculia (Latrunculia) ikematsui Tanita, 1968

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 : 39-40

Latrunculia (Latrunculia) ikematsui Tanita, 1968

( Figs 1J, 2 , 3D, 5A ; Tables 2 & 3)

Latrunculia ikematsui Tanita, 1968 , PG. 53–54, PL. 11, FIG. 11, TEXT­ FIG. 14.17. Latrunculia ikematsui Tanita ; Rho and Sim, 1976, Figs. 1 & 2A–D ; Latrunculia ikematsui Tanita ; Hoshino, 1981: 222.

Holotype material. NSMT PO 11 Latrunculia ikematsui Tanita, 1968 , Ariake Sea, Japan, dredged at St. 13, depth unknown, collected by Tanita, September, 1957.

Description. Small, semispherical sponge, 14 x 20 x 3 mm diameter ( Fig. 3D). Surface smooth with no oscules or areolate porefields apparent. Ectosome thin but not easily separable from the underlying choanosome. Texture firm and hard but resilient. Colour in life darkish purple; in preservative dark chocolate brown.

Skeleton. The choanosomal skeleton is a firm, well developed, irregular polygonalmeshed reticulation formed by wispy tracts of smooth styles ( Fig. 5A ). The tracts range in width from 45–91 m in thickness to form meshes that are 91–136 m wide. There is no distinction between the primary and secondary tracts. Towards the surface the spicules tend to be vertically arranged. Interstitial spicules present, with discorhabds scattered abundantly throughout choanosome. The surface of the ectosome is lined with an erect layer of anisodiscorhabds. Beneath the anisodiscorhabds in the ectosome is a thin, loose paratangential layer of interlocking megascleres, approximately 91 m wide.

Spicules. Megascleres: styles are smooth, centrally thickened, fusiform faintly sinuous, 300 (280–320) x 7 (6.5–8) m, n=20. Microscleres ( Fig. 1J): anisodiscorhabds, the manubrium is an expanded and spinose, above which are two basal spines on a smooth slender cylindrical shaft 12 m long and 5 m wide. Median whorl is circular, flat and horizontally arranged, 23 m in diameter, and the largest of the three whorls. The subsidiary whorl is slanted slightly upwards followed by an extended shaft, 5 m long, which gives rise to the apical whorl. Each whorl is deeply notched along the rim and divided into three segments, each possessing a denticulate margin of 5–7 spines. The spines of the apical whorl are slanted upwards with spines nearly parallel to the axis, ending in a crown­like tuft of acute convex spined projections, 38(32–38) m long.

Substratum, depth range and ecology. Found on sandy substrata, together with, bryozoans and other sponges. Depth unknown but dredged from deep water.

Geographic distribution ( Fig. 2 ). Korea; Japan.

Remark. Tanita (1968) first described this species off the Ariake Sea, Japan on the basis of the shape of its discorhabd, the dimension of spicules and its external morphology ( Table 2, 3). The distinguishing characteristic in this species is the morphology of the anisodiscorhabds; the median, subsidiary and apical whorls are leaf­like and lined with rows of spines.

Figures

FIGURE 2. Worldwide distributions of Latrunculia (Latrunculia) species. Distributions of 1) Latrunculia cratera du Bocage, 2) L. bocagei Ridley and Dendy, 3) L. apicalis Ridley and Dendy, 4) L. biformis Kirkpatrick, 5) Latrunculia basilis Kirkpatrick, 6) L. brevis Ridley and Dendy, 7) Latrunculia palmata Lévi, 8) Latrunculia multirotalis Topsent, 9) Latrunculia crenulata Lévi, 10) Latrunculia ikematsui Tanita, 11) Latrunculia oxydiscorhabda Alvarez et al., 12) Latrunculia triverticillata Alvarez et al., 13) Latrunculia fiordensis Alvarez et al., 14) Latrunculia novaecaledoniae sp. nov.

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.