Calthropella Pachataxa pyrifera, Van Soest, Rob W. M., Beglinger, Elly J. & De Voogd, Nicole J., 2010

Van Soest, Rob W. M., Beglinger, Elly J. & De Voogd, Nicole J., 2010, Skeletons in confusion: a review of astrophorid sponges with (dicho-) calthrops as structural megascleres (Porifera, Demospongiae, Astrophorida), ZooKeys 68, pp. 1-88 : 61-62

Calthropella Pachataxa pyrifera sp. n. Figs 31 A–E

Material examined.

Holotype HBOI nr. 12 –XI–86–1– 14, with fragment (schizoholotype) ZMA Por. 07726, Ecuador, Galapagos Archipelago, NE coast of Santa Cruz, Rocas Gordon, 0.546°S; 90.116°W, depth 506 m, coll. K. Rinehart, Johnson SeaLink submersible, 12 November 1996, don. S.A. Pomponi & M.C. Diaz.

Description.

Type material available to us has a flattened (Fig. 31A left), rounded shape, size 1 ×1× 0.2 cm. It is a fragment of a larger holotype specimen (3.5 ×3× 2.5 cm) that is massively rounded and may have a large central oscule (Fig. 31A right). Colour very pale green or dirty white.

Skeleton: an irregular mass of large triaenes covered at the periphery by a thick layer of ataxasters / microrhabds, which are also strewn in the interior. Loose oxeas of widely different sizes present in moderate quantities, considered foreign.

Spicules: calthrops, spheroxyasters, ataxasters.

Calthrops (Fig. 31B) variable in size and thickness, mostly with straight cladi, often one cladus slightly shorter, occasionally curved at the ends; cladi 133 –412.3– 708 × 15 –37.4– 71 µm, cladome 233 –626.8– 1180 µm.

Spheroxyasters (Fig. 31C), thick-centred with smooth conical rays, many of which appear underdeveloped causing an irregular aspect; extreme cases are the medusa-like forms such as pictured at lower right in Fig 31C, showing a deformed aster with rays present only at one side; diameter (including rays) 15 –18.1– 24 µm (centre approx. 10 µm diameter).

Ataxasters (Figs 31 D–E), typically pyriform (pointed one-sidely), occasionally ovate or rounded, microspined all over, but spines tend to be grouped; no branching shapes were found, making the term ‘ataxaster’ inappropriate for these spicules, but their homology to the ataxasters of Pachataxa lithistina is nevertheless obvious; size 7 –20.5– 31 µm, measured along the longest axis.

Etymology.

From the Greek pyros = pear and fero= carry or bear, referring to the possession of the pear-shaped microscleres.

Habitat.

Deep water, 506 m.

Distribution.

NE of Santa Cruz Island, Galapagos, East Pacific.

Remarks.

The species is assigned to Calthropella (Pachataxa) on the basis of its spiculation. Size and shape of the calthrops is similar to Calthropella (Pachataxa) lithistina , but these differ clearly in the diameter of the spheroxyasters (those of Calthropella (Pachataxa) pyrifera sp. n. are twice as large and these are also twice as large as those of Pachataxa enigmatica , see above). Especially the shape of the ataxasters renders this species distinct from the other two Calthropella (Pachataxa) .