Latrunculia (Biannulata) microacanthoxea Samaai and Kelly (2003)

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 : 57-58

Latrunculia (Biannulata) microacanthoxea Samaai and Kelly (2003)

(Figs 6A, 7, 8E, 9C; Tables 2 & 3)

Latrunculia microacanthoxea Samaai and Kelly, 2003 , PG13, FIGS 3B, 4C, H , 5C

Holotype material. BMNH 1996.7.3.1: Rheeders Bay , Tsitsikamma National Park, South Africa, 34º 10'S; 23º 54'E, collected by P. Coetzee, University of Port Elizabeth, 15 February 1995, 28 m.

Additional material. SAM H­4962: Rheeders Bay , Tsitsikamma National Park, South Africa , 34º 10'S; 23º 54'E, 28 m, collected by P. Coetzee, University of Port Elizabeth , 10 April 1995 .

Diagnosis. Small, semispherical sponge with numerous regularly spaced, low, cylindrical oscules and numerous short, thick lipped crater­like areolate porefields with a distinct net­like poral membrane ( Fig. 8E). Colour in life is olive green, mottled with brown patches, dark chocolate brown in preservative. Styles are hastate and smooth with slight irregular inflatations on shaft, 397 (374–422) x 9.6 (9.6) m. Anisodiscorhabds (Fig. 6A) are straight having both a bulky spinose manubrium and a small crown­like apex at the center of the apical whorl. There is also no basal whorl of spines present above the manubrium as characteristic for this subgenus. All whorls are notched along rim and divided into four segments, each segment with denticulate margins. Median and subsidiary whorls have secondary spines; 55 (50–60) x 7 (7.2–9.6) m. A second category of microscleres, microacanthoxeas which are thin and slightly blunt on both ends are present; 52 (50–55) x 3.4 m. The choanosomal architecture is a dense well developed irregular polygonal­meshed reticulation, becoming more regular and plumose towards the surface ( Fig. 9C ). Microacanthoxeas lines the tracts of the choanosome. The surface of the ectosome is lined with an erect layer of single non­interlocking anisodiscorhabds, separated by a mushroom­like ectosomal membrane that is clearly visible. The sponge whose habitat is rocky flats, at 28 m depth is often associated with coral, bryozoans and other sponges (after Samaai et al. 2003).

Geographic distribution ( Fig. 7 ). South east coast of South Africa.

Remarks. Latrunculia microacanthoxea is very similar to L. lunaviridis and is not easily differentiated from it in the field; both species are olive green and have similar surface morphologies of low cylindrical oscules and numerous short, thick­lipped craterlike areolate porefields. The species are differentiated primarily on the presence of curved polytylote styles ( L. lunaviridis ), the morphology of the microscleres, and the presence of microacanthoxeas in L. microacanthoxea . In L. microacanthoxea the manubrium of the anisodiscorhabd is bulky and irregularly spinose as appose to being stout and expanded as in L. lunaviridis . In L. microacanthoxea the apex, which are separated from the apical whorl, forms a small crown­like tuft, unlike the broad crown­like structure developed by the fusion of the apex and apical whorl as in L. lunaviridis . An unusual and quite consistent histological feature is the sparseness of the ectosomal palisade in L. microacanthoxea . The species are also well separated geographically, L. lunaviridis was found on the west coast while L. microacanthoxea is known only from Tsitsikamma National Park on the southern coastline.

The only other species of Latrunculia known to contain a second category of unrelated microscleres are L. oxydiscorhabda Alvarez et al. (2002) and the microacanthoxeas are quite different from the spinose amphiaster­like microscleres of L. oxydiscorhabda Alvarez et al. (2002) .

Figures

FIGURE 4. Photomicrographs of choanosomal architectures: A. L. bocagei Ridley and Dendy 1886; B. Latrunculia apicalis Ridley and Dendy 1886; C. Latrunculia biformis Kirkpatrick 1908; D. Latrunculia basilis Kirkpatrick 1908; E. Latrunculia brevis Ridley and Dendy 1887; F. Latrunculia multirotalis Topsent 1905.

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.

FIGURE 9. Photomicrographs of choanosomal architectures: A. Latrunculia oparinae Samaai and Krasokhin 2002; B. Latrunculia lunaviridis Samaai and Kelly 2003; C. Latrunculia microacanthoxea Samaai and Kelly 2003; D. Latrunculia kaakaariki Alvarez et al. 2002;