Polymastiidae (Demospongiae: Hadromerida) with ornamented exotyles: a review of morphological affinities and description of a new genus and three new species

Abstract

All polymastiid sponges displaying ornamented exotyles are reviewed and their morphological affinities are reconsidered. The study embraces all known species of Proteleia, Sphaerotylus, Trachyteleia and Tylexocladus as well as several species of Polymastia. A new genus, Koltunia, is established for the Antarctic species Proteleia burtoni based on the unique shape of distal ornamentations of its giant exotyles and on the absence of a spicule palisade in its cortex, a rare feature among the polymastiids. Three new species of Sphaerotylus are described -S. renoufi from the British Isles, S. strobilis from South Africa and S. tjalfei from West Greenland. Transfer of one New Zealand species from Polymastia to Proteleia and of one Chilean species from Polymastia to Sphaerotylus is proposed. The present study provides a background for future integrative phylogenetic analyses based on comprehensive molecular and morphological datasets which should reveal the natural relationships between the polymastiid taxa.

Polymastiidae (Porifera: Demospongiae) of the Nordic and Siberian Seas

“…However, here we follow the traditional taxonomy of Sphaerotylus spp. (Boury-Esnault, 2002; Plotkin et al ., 2016a), since no alternative classification is proposed for Polymastiidae so far (Plotkin et al ., 2016b).…”

“…The large morphological differences between S. borealis and the type species of Proteleia, P. sollasi Dendy & Ridley, 1886, were described by Plotkin et al . (2016a). At the same time S. borealis shares many features, e.g.…”

“…Sphaerotylus borealis (Rezvoj, 1928, p. 78, figures 4 & 5;description (according to Plotkin et al, 2016a) External morphology Sponges thickly encrusting or cushion-shaped, the largest up to 100 cm 2 . Surface shaggy, silted with sediment making it dirty greyish or brownish in colour.…”

“…Detailed description of the type material was presented by Plotkin et al (2016a). comparative material …”

Shaping highly regular glass architectures: A lesson from nature

“…The latter exhibit a fascinating diversity of the most intricate species-specific three-dimensional (3D) morphologies displaying high spatial regularity and symmetry ( Fig. 1 ) ( 4 , 5 ). Whether the spicules have a simple elongated needle-like shape ( Fig.…”