Haliclona (Flagellia) flagellifera ( Ridley & Dendy, 1886 ) Van Soest, 2017

Van Soest, Rob W. M., 2017, Flagellia, a new subgenus of Haliclona (Porifera, Haplosclerida), European Journal of Taxonomy 351, pp. 1-48 : 22-24

Haliclona (Flagellia) flagellifera ( Ridley & Dendy, 1886) subgen. et comb. nov.

Fig. 11

Gellius flagellifer Ridley & Dendy, 1886: 323 .

Gellius flagellifer – Ridley & Dendy 1887: 42, pl. XIII figs 5, 10.

Material examined

MARION ISLAND: small dry fragment of holotype, Marine Ecoregion Prince Edward Islands , depth 90–135 m ( BMNH 1887.5.2.252).

Description

Shape (from Ridley & Dendy 1887): two small, massive encrustations, largest is 2.9 cm in lateral expansion, 1.6 cm thick, color pale greyish (in alcohol). A single oscule. Surface shaggy. Consistency soft, brittle.

SKELETON. Haliclona -like, confuse, anisotropic, with primary lines consisting of 1–4 spicules, single spicules interconnecting at all angles, but mostly rectangular, no spongin visible. No special ectosomal arrangement of skeleton and spicules.

OXEAS ( Fig. 11 A–A1). Slightly curved, fat, cigar-shaped, gradually pointed, 340– 389. 1 –420 × 8– 15. 1 – 18 μm.

FLAGELLOSIGMAS ( Fig. 11 B–E). Elongated, elliptical, larger strongly asymmetrical, smaller less so and less elliptical, more ovoid. Curvature of long ending shortly rounded, no upturned hook, curvature of short ending shallow, in a wide size range, suggesting two overlapping size categories but subtly distinguishable by shape. Larger (I) ( Fig. 11 B–C) with length of long ending 82– 96. 2 –102 μm, length of short ending 50– 60. 6 –75 μm, width 50– 60. 2 –73 μm, thickness 2.5– 2. 8 –3 μm. Smaller (II) ( Fig. 11 D– E) with length of long ending 45– 54. 6 –66 μm, length of short ending 33– 39. 8 –48 μm, width 33– 41. 5 – 46 μm, thickness 1– 1. 7 –2 μm.

NORMAL SIGMAS ( Fig. 11F ). A single size category, tips slightly incurved, 31– 39. 6 –53 × 1.5– 2. 2 –2.5 μm.

Remarks

Although cosmopolitan distribution is unlikely to occur in sponge species with a depth range limited largely to continental and upper bathyal waters, it is still possible that the present species from an oceanic island could have been capable of covering large distances. Thus, the reported occurrence of H. (F.) flagellifera from circumglobal southern ocean localities could be consistent with the occurrence of a single species. Here the literature data from the non-tropical southern ocean records of the species is reviewed. Despite numerous reports (see Remarks below), we consider that the only reliable record of H. (F.) flagellifer originates from the type locality at Marion Island (South African administration).

Boury-Esnault & Van Beveren (1982) reported Gellius flagellifer from Kerguelen Islands at a comparable depth of 195 m. The shape of their specimens was also massive encrustations, up to 4.3 × 3 × 0.8 cm. The oxeas were reported as 474– 540 –589 × 13– 14 –24 μm, clearly longer than those of the type. The flagellosigmas had their longest axis 88– 98 –129 μm (= length of long ending) and their shorter axis 45– 56 –67 μm (= width), close in measurements to those of the type specimen, but no small flagellosigmas were mentioned. The shape of the flagellosigma in their paper is more narrow-elliptical than in the type, and the long ending has a faint upturned hook. Normal sigmas have a wider range, 40– 83 –131 × 2–5 μm, and in the illustrations clearly appear to be divisible into two sigma size categories unlike the normal sigmas in the type. Therefore it is uncertain whether the Kerguelen material is conspecific with the type, and for now is considered to belong to an unnamed Haliclona (Flagellia) spec. until the specimen can be examined.

Burton (1938) reported the species (as Adocia ) from Eastern Antarctic Wilkes Land, directly south of Australia, at a depth of 36 m. He provided no data, other than remarking that the flagellosigmas reached 120 μm in the longest axis, a similar length to those of the type, but not sufficient to conclude that the Antarctic specimen is conspecific. Göcke & Janussen (2013) reported this species from the Eastern Weddell Sea, Antarctica, at a depth of 602 m. Oxeas were 570– 643 –715 × 22– 26 –29 μm, clearly considerably longer and thicker than the type. Flagellosigmas measured 80– 106 –140 μm in the longest axis, 60– 109 –155 μm in the shorter axis, also larger than the type specimen. The normal sigmas were 17– 24 –31 μm, smaller than in the type. Although generally similar to the type, the spicule size data and the lack of differentiated larger and smaller flagellosigmas indicates a likely specific difference.

It is not possible to judge whether specimens reported by Pansini & Sarà (1999) from Magellan Strait are similar to the type specimen, because no description was provided.

Dendy (1924) and Bergquist & Warne (1980) reported specimens from northern New Zealand waters (Three Kings Islands), at depths of 200 m and 60–120 m, respectively. The specimens differed in the size of the oxeas, with Dendy’s specimen possessing oxeas of only 210 × 8 μm, while those of Bergquist & Warne were close to those of the type in size, 460 × 15 μm. Both specimens had small flagellosigmas of 46 and 64 μm respectively, and a single size of normal sigmas (20 and 28 μm respectively). Neither specimen appears very close to the type morphologically.

Uriz (1987, 1988) described Gellius flagellifer from Namibia, SE Atlantic (at depths of 183–290 m). The oxeas were given as 420–570 × 16–30 μm, much larger than the type. In addition, the flagellosigmas and normal sigmas were larger, suggesting that the Namibian material could be specifically different.

Samaai & Gibbons’ (2005) description of Haliclona (Gellius) flagellifer from the Atlantic coast of South Africa (15 m) differs from Uriz’ material and from the type of H. (F.) flagellifera in having two size classes of normal sigmas, 73–91 μm and 25 μm.

These comparisons lead to the conclusion that Haliclona (Flagellia) flagellifera is so far endemic to Marion Island of the Prince Edward Islands archipelago in the Southern Indian Ocean. Specimens reported as Haliclona (Gellius) flagellifera from other ocean basins are regarded as likely different species.

Figures

Fig. 11. Haliclona (Flagellia) flagellifera (Ridley & Dendy, 1886) subgen. et comb. nov., holotype, fragment of BMNH 1887.5.2.252, from Marion Island, South Indian Ocean, SEM images of the spicules. A. Oxea. A 1. Detail of one of the apices. B–C. Large category of flagellosigmas (I). C 1. Detail of long ending of large flagellosigma. C 2. Detail of short ending of large flagellosigma. D–E. Small flagellosigmas (II). F. Sigmas.