Kanakaster balutensis

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 : 25-27

Kanakaster balutensis n. gen, n. sp.

Figure 7 A–E

Etymology. The species name refers to the holotype’s collection locality, Balut Island in the Philippines.

Diagnosis. This species is diagnosed by the presence of the bald patches present on the superomarginal plates and the absence of embossed crystalline bosses from the marginal plate surface. Distalmost superomarginals abutted on each arm tip.

Occurrence. Known only from Balut Island, Mindanao, Philippines. 200–250 m.

Description. Body stout, stellate (R/r=1.83), interradial arcs weakly curved ( Fig. 7 A). Arms blunt, triangular in shape. Abactinal, marginal, actinal surfaces covered by granulated tegument ( Figs. 7 B, C). Pedicellariae not observed on any surface.

Abactinal plates strongly convex, polygonal to round in outline (many hexagonal) ( Figs. 7 A, B). Plate size largely homogeneous with primary plates in each interradius approximately two to four times the size of adjacent abactinal plates. Each interradius with paired plates along midline. Granulated tegument thick, obscuring boundaries between plates ( Fig. 7 C), approximately six to eight granules counted along a 1.0 mm line. When tegument is removed, individual plates with embossed crystalline bosses arranged in radiating, evenly spaced patterns, 40–200 per plate, centered primarily around middle plate. Madreporite round in outline, flanked by three plates, relatively large; similar in size to larger primary plate. Papulae present primarily over radial regions, absent interradially, approximately six surrounding each plate. Central region weakly convex but most of abactinal surface mostly flat.

Superomarginal plates 18–20 per interradius, inferomarginal plates 20–22 per interradius (both counted from arm tip to arm tip) ( Fig. 7 A). Counts are obfuscated by irregular superomarginal plate arrangements near arm tips. Superomarginals elongate, strongly rounded in cross-section, quadrate in outline ( Fig. 7 C). Distal superomarginal/ inferomarginal plate correspondence is offset with zig-zag contact. Distalmost superomarginals abutted over midline with up to five superomarginal plates in contact near arm tip ( Fig. 7 A). Superomarginal plates covered by granulated tegument save for distinct, bare region present on the abactinal surface of nearly all superomarginals ( Fig. 7 C). Presence on the superomarginals is variably sized and although present on most plates, can be irregularly absent. Bare region not observed on inferomarginal surface. Individual marginal plates wide (W>L) with rounded edge interradially becoming more elongate distally along arm. Other than bare region on superomarginals, no other accessories or structures observed under granular tegument on marginal plate surface. Terminal plate triangular with smooth surface.

Actinal surface well-developed with more than five fully developed series in chevron like arrangement ( Fig. 7 D). As with other surfaces, the granular tegument forms a continuous cover over the actinal surface and obscures boundaries between individual plate boundaries, but when cleaned, plates are primarily quadrate in shape ( Fig. 7 E). No other structures or accessories (e.g. pedicellariae, spinelets, etc.) were observed on the actinal surface or on the plate surface underlying the granular tegument. One or two tong-shaped pedicellariae was observed in each of the five interradii on a relatively deep depression adjacent to the oral region.

Furrow spines in a single series ( Fig. 7 E), each spine blunt, three spines on most adambulacral plates, exceptionally two. Spines triangular in outline arranged in complimentary fashion with other adjacent furrow spines. Adambulacral plate surface covered by granulate tegument up to the base of each furrow spine with no accessory structures (i.e., spinelets, enlarged granules, etc.) present on adambulacral plate surface. Granulation on oral plates is approximately twice as large as the granulation on the remaining actinal surface and appears to be more scalar in morphology. Oral plates ( Fig. 7 E) with three large (twice as wide as other furrow spines), blunt furrow spines and with one blunt spine from each oral plate (total of two) projecting into the mouth.

Material examined. Holotype: CASIZ 185669 ; Balut Island, Mindanao , Philippines, 200– 250 m .; 1 dry spec. R=5.5, r=3.0. Paratype: CASIZ 185668 ; Balut Island, Mindanao , Philippines. 200–250 m., 1 dry spec. R=5.8, r=2.5.

Figures

FIGURE 7. Kanakaster balutensis n. gen., n. sp. Holotype, CASIZ 185668. A. Abactinal surface. Scale bar = 8.0 mm B. A bactinal plate detail. Scale bar = 3.0 mm. C. Abactinal-lateral view showing superomarginal plate detail. Scale bar = 2.0 mm D. Oral surface. Scale bar = 8.0 mm E. Detail of oral region, furrow spines. Scale bar = 3.0 mm