Kanakaster larae

Mah, Christopher L., 2017, Overview of the Ferdina - like Goniasteridae (Echinodermata: Asteroidea) including a new subfamily, three new genera and fourteen new species, Zootaxa 4271 (1), pp. 1-72 : 32-34

Kanakaster larae nov. sp.

Figure 10 A–E

Etymology. This species is named for Dr. Lara Atkinson, South African Environmental Observation Network, a dedicated supporter of South African marine biodiversity research.

Occurrence. East coast of South Africa, 120–125 m.

Diagnosis. Weakly stellate/pentagonal body form. Bare patches on the superomarginal plates absent. Body surface completely covered by soft granular tegument with no bare spots on marginal plates. When underlying tegument has been removed, abactinal and marginal surface with glassy nodules (also called embossed crystalline bodies). Fifteen to sixteen marginal plates present per interradius (arm tip to arm tip).

Taxonomic comments. Superomarginal and inferomarginal plates in Kanakaster larae n. sp. are wider (width>length) than those observed on Kanakaster discus or K. plinthinos n. sp. which are elongate. Although only a single specimen of K. larae has been collected, larger specimens of the similar K. discus at R= 2.1 cm show consistently fewer marginals which are distinctly wide rather than elongate. These characters are inconsistent with K. discus as the same, but smaller individual of the same species as K. larae n. gen, n.sp.

Description. Pentagonal/weakly stellate body form (R/r=1.5), interradial arcs weakly curved( Fig. 10 A). Body surface covered by finely granulate tegument, obscuring plate boundaries when well-developed, soft to the touch ( Fig. 10 A, C).

Abactinal surface covered by granulate tegument which covers plates and spaces between them. Granules eight to 10 along a 1.0 mm line with coarser granules present between abactinal plates and around papular pores. Abactinal plates round to polygonal, mostly homogeneous in size with smaller more irregularly shaped plates present adjacent to superomarginal contact ( Fig. 10 B). Abactinal plates extend for approximately 50% of arm distance tapering out as superomarginals abut over midline. Abactinal plates relatively large, approximately three to five present across arm base. Most carinal plates are circular in outline with some more distal plates becoming more oval shaped to irregular shaped ( Fig. 10 A). Granular tegument/skin covers abactinal plates completely with no bare patch observed. No separate granulation present around plate periphery. Individual plates when denuded show 10 to 80 crystalline bosses embedded in plate surface in evenly arranged ordered patterns. Some individuals display more lobate crystalline structures rather than discrete round bosses. Each interradial region with discrete depression present adjacent to midline interradius; paired plates present in each interradius around this midline. Papulae present radially, absent interradially. Six papular pores present around each plate, each pore with two to four, mostly three eye drop shaped granules present. These papular granules about three to five times the size of the granules present on the abactinal surface. Madreporite round to triangular in shape, flanked by three large plates in most individuals observed. No pedicellariae observed.

Distalmost plates showing zigzag contact on three to six plates from arm tip. Holotype with R= 3.2 cm, showing 15–16 marginal plates per interradius, displaying wide plates (W>L) in outline and quadrate edges. Granular tegument covers all marginal plate surfaces ( Fig. 10 C). Inferomarginal surface shows more coarse grained granules relative to superomarginals. When tegument has been removed, marginal plate surface is smooth and bare but with 20–100 (usually 40–80) embossed crystalline bosses present on the surface of each marginal plate (i.e., both superomarginals and inferomarginals). No other surficial or peripheral accessories observed. No pedicellariae observed. Terminal plate triangular with smooth surface.

Actinal plates in two complete chevron-like series with a third irregular arrangement of plates adjacent to the inferomarginal plates ( Fig. 10 D). Plates are mostly quadrate in shape. Actinal surface covered by granulate tegument nearly obscuring boundaries between plates ( Fig. 10 D, E). When denuded plates are bare with no accessories, lacking crystalline bosses (although adjacent inferomarginal plates do display glassy bosses on actinal surface).

Three blunt furrow spines per plate ( Fig. 10 E). Furrow spines blunt, each triangular to polygonal in crosssection, sitting in single series arranged at complimentary angles to one another. Spines arranged in straight line or very weakly curved. No subambulacrals or other adambulacral accessories ( Fig. 10 E). Adambulacral plate surface covered by granulate tegument which forms consistent cover over actinal plates right up to base of furrow spines. Oral plate with three furrow spines and one blunt spine, paired on each oral plate, triangular in cross-section, directed into mouth (= two spines present in each interradius). No other surficial accessories on oral plate other than granules present from continuous granular tegument.

Material examined. South Africa. Holotype: MB-A 081514 (Iziko). Port Edward, 120–125 m. 08-07-1985. Coll. G. Williams. st. XX59. 1 wet spec. R=3.2, r=2.1.

Figures

FIGURE 10. Kanakaster larae n. gen., n. sp. Holotype, MB-A 081514 (Iziko). Scale Bar = 4.0 mm. A. Abactinal surface. B. Abactinal surface detail. C. Abactinal surface contact with superomarginal plate series. D. Actinal surface. E. Oral region, furrow spine details.