Kampylaster incurvatus Koehler 1920

Mah, Christopher L., 2023, New Genera, Species, and observations on the biology of Antarctic Valvatida (Asteroidea), Zootaxa 5310 (1), pp. 1-88 : 22-24

Kampylaster incurvatus Koehler 1920

FIGURE 6A–G

Kampylaster granulatus Koehler 1920: 8 (nomen nudum)

Kampylaster incurvatus Koehler 1920: 138 ; Fisher 1940: 150; Madsen 1955: 13; H.E.S. Clark 1963: 48.

Diagnosis

Body weakly stellate (R/r=1.0 at R=1.1.7). Marginal plates and lateral edge with round granules, forming rounded, thick edge with close-set granules extending onto the distal actinal intermediate areas adjacent to the inferomarginals ( Fig. 6C ). Granules round, homogeneous in size and shape, close set ( Fig. 6B, G ). Furrow spines, 3–4, elongate, unwebbed, widely spaced in transverse series relative to tube foot furrow.

Comments

One specimen (USNM 1183749) was found with 12 brooded juveniles ( Fig. 6C, D, E ). This is the first account of brooded juveniles since Fisher (1940) described brooding specimens from the Ross Sea. Juveniles described herein are slightly larger (R= 18 mm) than those described by Fisher (R= 15 mm). Three were found in the mouth cavity rather than adjacent to the mouth.

Occurrence

Enderby Land east to the Ross Sea. D’Urville Sea (off coast of Adelie Land), Terre Adélie. Palmer Archipelago, Scotia Sea, and South Shetlands. 6–935 m. (depth range extended)

Description

Body thick, arched, shape is pentagonal to stellate (R/r=1.1–2.2), interradial arcs weakly curved, lateral edge crenulate ( Fig. 6A, C ).

Abactinal plates flattened, imbricate, closely articulated, individually oval to round oblong in shape. With granules removed, plates smooth, flat ( Fig. 6F ). Surface covered by evenly distributed granules, round, approximately 3 to 6 (5) along a 1.0 mm line (at R= 1.5 cm), variably widely to closely spaced. Granules form part of surficial cover that obscures plate boundaries. Granules variably round to flat topped. Papulae single, widely spaced on disk at arm base. Papulae absent from interradial and distal arm regions. Madreporite convex like but surface flush with plate surface, covered by and obscured by granules, sulci shallow.

Marginal plates forming rounded, crenulate edge ( Fig. 6C ). Superomarginals and inferomarginals flattened to weakly concave, imbricate, approximately 28–30 per interradius at R=1.5. Superomarginals and inferomarginals offset with inferomarginals forming a sinusoidal contact with superomarginals. Marginals obscured by round granules, identical to those on abactinal plates ( Fig. 6G ). Marginal plate surfaces smooth and clear after granules have been removed. Inferomarginal plates, with 8–14 blunt, cylindrical granules in irregular arrangement, forming dorsolateral edge along disk and arms.

Actinal surface composed of plate series in linear rows between inferomarginals and adambulacrals. Granular cover from inferomarginal plates continues onto periphery of actinal intermediate surface, acutely transitioning to spines. Actinal plates round to irregular in shape, flattened each with 1 to 5 blunt spines ( Fig. 6C ). Area adjacent to oral plates with larger, irregular shaped tissue filled space. Dermis covers actinal intermediate plates.

Furrow spines, 3 to 4, elongate, unwebbed, widely spaced in transverse series relative to tube foot furrow ( Fig. 6C ). Oral plate furrow spines 4, decreasing in length with longest spines projecting directly into mouth, shortest spine adjacent to opening of tube foot furrow. Oral plate surface with no surficial accessories. Distinct ridge along midline of oral plate surface where tissue filled fossae is present between the two half plates.

Brooded Juveniles

One individual (USNM 1183749) was found with 12 brooded juveniles adjacent to its mouth and oral space ( Fig. 6C ). Three remain in the oral cavity with the others separated. Individuals were all similar in size with R=1.8 r= 1.6 cm. Body shape more pentagonal at this size, R/r=1.1 ( Fig. 6D, E ).

Abactinal surface was covered with pointed spinelets with inferomarginals approximately twice the length. Spinelets with roughened surfaces, jagged tips. Actinal plates not observed. Inferomarginal plates in direct contact with adambulacral plates. Furrow spines 1 or 2 per adambulacral plate, 4 along each arm series at this size ( Fig. 6E ). Oral plates with 4 such spines. Spines similar to those of inferomarginals, with roughened surfaces, jagged tips.

Figures

FIGURE 6. Kampylaster incurvatus USNM 1183749 showing brooded juveniles. A.Abactinal surface. B. Close up of abactinal surface showing granules. C. Actinal surface showing brooded three juveniles. D–E. Abactinal and Actinal view, brooded juvenile. F. Armtip showing denuded abactinal and marginal plates. G. Armtip showing abactinal and marginal plates with full granular cover.