Asbestopluma (Asbestopluma) anisoplacochela, Kelly, Michelle & Vacelet, Jean, 2011

Kelly, Michelle & Vacelet, Jean, 2011, Three new remarkable carnivorous sponges (Porifera, Cladorhizidae) from deep New Zealand and Australian (Macquarie Island) waters, Zootaxa 2976, pp. 55-68 : 60-62

Asbestopluma (Asbestopluma) anisoplacochela sp. nov.

( Fig. 4 )

Material examined. Holotype. NIWA 25835, NZOI Stn U618, Three Kings Ridge ( New Zealand EEZ), 33.115°S, 173.302°E, 1690 m, 12 Feb 1988, rock dredge.

Type locality. Southern reaches of the Three Kings Ridge, northeast of Thee Kings Islands ( New Zealand EEZ).

Description. Several fragments of an erect, cylindrical sponge, 0.7-2 mm in diameter ( Fig. 4 A). The larger fragment is 210 mm long, ending in a slightly enlarged part, bearing short swellings, most probably remains of lateral expansions laterally opposed. Color, light brown in the parts covered by the spicule feltwork, whitish in the axis and on the terminal swellings. No visible aquiferous system.

Skeleton. Skeleton of the main axis is composed of longitudinally arranged mycalostyles, the swellings have a secondary axis of similar styles. Most parts of the main axis are lined by a dense feltwork of acanthotylostrongyles, including numerous shells of foraminifera and sand grains. Microscleres irregularly line the terminal part of the axis and the lateral swellings, and are rare on the basal part of the axis. Attachment base absent.

Spicules. Megascleres ( Fig. 4 B–D), mycalostyles ( Fig. 4 B,C) of the axis of the stalk and lateral swellings, slightly curved, sometimes a little flexuous or fusiform, with a blunt point; 650– 1650 x 10–30 µm. Acanthotylostrongyles ( Fig. 4 D) forming a feltwork around the main axis, slightly curved or flexuous, covered with numerous short, curved spines, head slightly inflated or with a faint annular swelling after the head, end abruptly blunt; 130– 310 x 2–3 µm. Microscleres ( Fig. 4 E–K), anisoplacochelae ( Fig. 4 E-H), rather numerous and of a large size, with two unequal ends. Large end with a central tooth enlarged in an oval plate, up to 25 µm wide, bearing curved spines regularly arranged along the edge of the inner surface. Smaller end with two small lateral alae and a large central tooth, strongly curved and spoon–shaped, with the edges irregularly crenulated ( Fig. 4 H). Shaft straight and enlarged, with edges wrapping inwards to form a trough lined with curved spines on the inner surface facing the large end, irregularly crenulated on the rest of the inner edge near the base of the spicule. Immature spicules are smooth, without enlarged tooth; 180–220 µm total length, large tooth with a plate; 25 µm wide. Anisochelae ( Fig. 4 K) moderately numerous, head with large alae attached to the shaft by their whole length and a large central tooth. Free shaft short, abruptly curved. Foot with two small alae, and an ovoid tooth ending in a short point, very regular; 10.5–10.8 µm total length. Sigmancistras ( Fig. 4 J), numerous, twisted on 90°, without notch; 27–32 µm x 2.5–3 µm.

Etymology. Named for the presence of anisoplacochelae, a microsclere resembling the placochelae of the poecilosclerid family Guitarridae , but with unequal ends.

Remarks. The fragments most probably belong to a single, broken specimen, which is poorly preserved and incomplete, but which likely had the pinnate morphology commonly found in various genera of carnivorous sponges. The spicule complement and the general organization of the new species are typical of Asbestopluma , but the species is well characterized by the presence of a remarkable new type of microsclere of very large size. This spicule, for which we propose the term ‘anisoplacochelae’, has a plate-like central tooth similar to that of the placochelae of Guitarridae and of Euchelipluma , but with two dissimilar ends, and thus clearly deriving from an anisochelae instead of an isochelae.

The anisoplacochela has no equivalent in sponges with placochelae or related spicules ( Uriz and Carballo, 2001). They could have been derived either from a placochelae, or represent a derivative of anisochelae homoplasic to the placochelae of Guitarridae and Euchelipluma . In our opinion, the second hypothesis, which does not imply a relationship with Guitarridae , is more likely at this stage.

The presence of numerous foraminiferan shells is also remarkable. This character is shared with A. (A.) agglutinans Vacelet, 2006 , which has remarkably similar small anisochelae and sigmancistras, but which differs in other spicule characters.

Figures

FIGURE 4. Asbestopluma (Asbestopluma) anisoplacochela sp. nov.: A. holotype NIWA 25835; B. styles; C. style; D. acanthotylostrongyle and close up of the head; E. anisoplacochela, profile view; F. anisoplacochela face view; G. anisoplacochela; H. anisoplacochela, small end; I. anisoplacochela, development stage; J. sigmancistra; K. anisochelae.