Kanakaster plinthinos

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 : 34-36

Kanakaster plinthinos n. gen, n. sp.

Figure 11 A–E

Etymology. This species is named from the Greek plinthos in reference to the resemblance of the plates to brick.

Occurrence. New Caledonia, 275–350 m.

Diagnosis. This species is recognized by the distinctly fewer marginals per interradius (six to eight) which are abutted over the mid-radius for most of the arm distance and by the distinctive triangular to polygonal bare patch on the surface of the each superomarginal. Of the twenty specimens examined, only two exceeded R> 1.2 cm; the largest individual with R= 1.5 cm. Removal of the granular tegument reveals glassy granules present embedded in the surface of each plate.

Taxonomic comments. Kanakaster plinthinos n. sp. displays superficial similarities to Kanakaster discus n.gen. n.sp. but differs in that it possesses small clear raised bald patches on the center of each superomarginal plate and possesses numerous granule-shaped nodules rather than the curved, finger-print like patterns observed in K. discus n. sp. The interradial arcs in this species are more angular than K. discu s which has interradial arcs that are weakly curved to linear.

Description. Body stout, pentagonal to stellate (R/r=1.2–2.2) outline, interradial arcs weakly rounded ( Figs 11 A, E). Body covered by dark, granulate tegument.

Abactinal plates round to weakly polygonal ( Figs. 11 A, E). Primary circlet with relatively large plates occupying approximately 1/3 of the r distance (center to edge of disk). Three carinals present from primary circlet to proximal region of arm. Glassy nodules in a radiate pattern present on surface where granular tegument has been removed. Each interradius with paired polygonal plates associated with interradial superomarginal plates. Madreporite with shallow sulci, present on one of the primary circlet plates in the holotype. Tegument shows some texture between abactinal and superomarginal plate contact.

Marginal plates, six (R= 1.1 cm) to eight (R= 1.2 cm) with distalmost two pairs of superomarginals abutted over midline ( Figs. 11 A, E). Penultimate superomarginals larger than interradial plates and more broadly triangular in shape. All superomarginal plates with polygonal, triangular, to quadrate, slightly darkened, bald patch, centrally on each interradial plate ( Figs. 11 B, E); absent from penultimate plates is variably better defined in some individuals (e.g., MNHN-IE-2013-6856 at R= 1.1 cm).Tegumental texture on marginals and abactinal disk adjacent to superomarginals is granulate in appearance owing to surficial texture of marginals with small, glossy granules present on each plate. Inferomarginals with single bald patches and coarse, granular tegument.

Actinal plates in two and one half-unusual chevron series with surface covered by a coarse, granular tegument ( Figs. 11 , C, D). No other accessories present on actinal plate surface. Furrow spines in a linear row, approximately two per plate ( Fig. 11 D). Adambulacral surface covered by granular tegument, no adambulacral or subambulacral spination/accessories, continuing along oral plates to tip projecting into mouth. One short, blunt spine projecting into mouth.

Color of preserved specimen dark red/brown, underside, white.

Material examined. Holotype: MNHN-IE-2013-6890; Offshore Havannah Canal on blocks and coarse sand, New Caledonia, 22°15’S, 167°08’E, 350–365m ; Coll. Richer de Forges aboard N/ O Vauban, MUSORSTOM 4; 1 wet spec. R=1.5, r=0.9. Paratypes: MNHN-IE-2007-6566; Canal de l’Havannah , New Caledonia, 22°15’S, 167°13’E, 406–442m.; Coll. EXBODI, CP 3786. 2.9.11. 2 wet specs. R=1.2, r=0.6; R=1.1, r=0.5. MNHN-IE-2007- 6583; Canal de l’Havannah , New Caledonia, 22°15’S, 167°13’E, 406 – 442m.; Coll. EXBODI CP 3786. 2.9.11;1 wet spec. R=0.9, r=0.5. MNHN-IE-2013-6892; Crypthelia Bank , New Caledonia 23°17'S, 168°14’E, 275–348 m ; Coll. Lozouet, Samadi & Richer de Forges, NORFOLK 2, DW 2125; 2 dry specs. R=1.0, r=0.8; R=0.7, r=0.4. MNHN-IE-2013-6894; SE New Caledonia, 23°15.7, 168°4.4; Coll. SMIB 5 ; 5 dry specs. R=0.9, r=0.7; R=0.8, r=0.7;R=0.9, r=0.6: R=0.8, r=0.6: R=0.7, r=0.3. MNHN-IE-2013-6893 ; New Caledonia, 23°19.6S, 163°4.7’E, 290–305 m; Coll. ORSTOM-SMIB 5, DW 102. 14 Sept. 1989; 5 dry specs. R=1.0, r=0.7; R=0.9, r=0.6; R=0.6, r=0.5; R=0.7, r=0.5. R=0.7, r=0.5; MNHN-IE-2013-6895 ; Île des Pins, New Caledonia, 22°42’S, 167°10’E, 313 – 315 m. Coll. NORFOLK 2, CP2160; 2 dry specs. R=1.1, r=0.7; R=1.0, r=0.7. MNHN-IE-2013-6896; Crypthelia Bank , New Caledonia 23°17’S, 168°14’E, 275 – 348 m.; Coll. Lozouet, Samadi & Richer de Forges, NORFOLK 2, DW 2125; 1 dry spec. R=1.1, r=0.7. MNHN-IE-2013-6856; off Noumea , New Caledonia, 23˚39.7’S, 167˚59.7’E, 280 m.; Coll. N.O Vauban, SMIB 3 , St. DW 20; 1 dry spec. R=1.1, r=0.7. MNHN-IE-2013-8396 ; New Caledonia, 22°44’S, 167°09’E, 340–345 m; Coll. MUSORSTOM 4, N/ O Vauban; 1 wet spec. R=1.1 r=0.6. MNHN-IE-2013- 8397 ; New Caledonia, 23° 20' S, 168° 16' E to 23° 21' S, 168° 16' E, 340–619 m.; Coll. NORFOLK 1, DW 1729; 1 wet spec. R=0.9 r=0.8.

Figures

FIGURE 11. Kanakaster plinthinos n. gen., n. sp. Holotype (A through D), MNHN-IE- 2013 - 6890. Scale Bar = 2.0 mm. A. Abactinal surface B. Superomarginal plates with arrows showing positions of bald patches on plates. C. Actinal surface. D. Actinal surface detail of mouth and furrow spines. E. Abactinal surface of paratype MNHN-IE- 2013 - 6894. Scale Bar = 2.0 mm. Pentagonal body form with arrows showing position of bald patches on superomarginal plate surfaces.