Aquilonastra donia, O’Loughlin & Bribiesca-Contreras, 2017

O’Loughlin, P. Mark & Bribiesca-Contreras, Guadalupe, 2017, New asterinid seastars from the western Pacific Ocean (Echinodermata: Asteroidea), Memoirs of Museum Victoria (Mem. Mus. Vic.) 76, pp. 121-132 : 122

Aquilonastra donia sp. nov.

Zoobank LSID. http://zoobank.org/ urn:lsid:zoobank.org:act:

C41D2993-A090-4D51-A8B9-C15A29B271B3

Figures 1 , 2 , 3a–d .

Material examined. Holotype. New Caledonia, Yaté reef flat, coll. Gaillande, July 1970, MNHN-IE-2014-641 (original registration MNHN EcAs11855) (dry; many spinelets and pedicellariae lost with handling over time).

Description. Asterinid seastar, five sub-equal rays, rays wide basally, bluntly rounded distally, R = 22 mm, r = 15 mm, rays merge at bases, inter-radial junction of rays shallow in-curved, central rays elevated and rounded abactinally, distinct broad inter-radial low non-papulate apron marginally, rays flat actinally, margin acute. No abactinal or actinal gonopores detected. Single madreporite.Not fissiparous.Superomarginal and inferomarginal plates sub-equal, superomarginal plates in discrete series, slightlylargerthanadjacentdistalabactinalplates, inferomarginal plates projecting outwards. Broad low marginal apron up to 7 plates across longitudinally, supported by internal superactinal plates; superambulacral plates present, small. Glassy convexities on cleared abactinal and actinal plates.

Abactinal: disc discrete, small, demarcated irregularly by 5 wide doubly papulate radial plates and 5 smaller inter-radial plates; single conspicuous madreporite, above junction of bases of two rays; pedicellariae present inter-radially, proximally and distally, conspicuous, frequently longer than adjacent spinelets, each comprising two stout, in-curved pointed conical teeth, present on proximal edges of inter-radial plates over concave indentation for papula; abactinal plates imbricate, indented proximally for single papula; no regular carinal series of plates, but a few doubly papulate carinal plates along some proximal upper rays; few small secondary plates on disc, rays and marginal apron; abactinal papular plates in about 7 longitudinal series down each side of each ray, plates with elevated rounded proximal edge, about 20 papular plates in uppermost series, 1–2 in lowest series; distal inter-radial plates on apron in longitudinal series parallel to the rays and oblique curved series from the ray to the margin. Abactinal spinelets readily lost: up to at least 20 digitiform spinelets over crown of proximal plates, not in tufts, distal spinelets slender conical to subsacciform; up to about 5 slender conical spinelets per superomarginal plate.

Actinal: inter-radial plates in longitudinal series parallel to the ambulacrum and oblique transverse series from the ambulacrum to the margin. Actinal spines per plate: oral 6, long digitiform to conical proximally, to short distally; suboral about 5, long conical proximally to short distally; furrow 4–5 long conical; subambulacral 4–5 long conical; actinal 2–3, mostly 2, long conical; inferomarginal up to about 16, thick digitiform actinally to thin conical subsacciform abactinally.

Distribution. New Caledonia, reef flat.

Etymology. Original collection record is New Hebrides, now New Caledonia, and named for the donia ending to Caledonia.

Remarks. The long abactinal pedicellariae, with 2 conical pointed and curved valves that are frequently longer than adjacent spinelets, and actinal inter-radial plates with predominantly 2 spines, are distinguishing feature of Aquilonastra donia sp. nov. Other Aquilonastra species with prominent pedicellariae with differentiated valves (teeth) are distinguished by: Aquilonastra anomala (H.L. Clark, 1921) is fissiparous with multiple madreporites; Aquilonastra batheri ( Goto, 1914) has tufts of splayed abactinal spinelets, and up to 12 actinal inter-radial spines; Aquilonastra corallicola ( Marsh, 1977) is fissiparous and has two different forms of spinelets on the paxilliform upper ray plates; Aquilonastra coronata ( Martens, 1866) has irregularly distributed high paxilliform abactinal plates with two different forms of spinelets; Aquilonastra iranica ( Mortensen, 1940) has up to 5 doubly papulate proximal carinal plates and the spinelets on proximal abactinal plates are in small groups; Aquilonastra richmondi O’Loughlin and Rowe, 2006 has spinelets of two forms on abactinal plates; Aquilonastra rowleyi O’Loughlin and Rowe, 2006 has a disc that is delineated by a dense band of spinelets on wide radial plates, each plate with about 100 long thin pencil-like glassy spinelets; Aquilonastra shirleyae O’Loughlin, 2009 has spinelets in splayed clusters and up to 10 actinal inter-radial spines per plate; Aquilonastra watersi O’Loughlin and Rowe, 2006 has abactinal spinelets in clusters.

Figures

Figure 1. Montage photograph of the holotype of Aquilonastra donia sp. nov. (MNHN-IE-2014-641). Abactinal view showing five sub-equal rays, distinct low marginal apron, absence of carinal series of plates, presence of rare doubly papulate carinal plates, and single large madreporite. The abactinal plates have become denuded of most spinelets over time.

Figure 2. Montage photograph of the holotype of Aquilonastra donia sp. nov. (MNHN-IE-2014-641). Actinal view showing five sub-equal rays, spination, longitudinal and oblique-transverse series of actinal plates.

Figure 3. Montage photographs of the holotype of Aquilonastra donia sp. nov. (MNHN-IE-2014-641): a, abactinal view of disc, single large madreporite, some remaining digitiform spinelets, and pedicellariae (highlighted); b, abactinal details of distal interradius showing pedicellariae (highlighted), and conical to sub-sacciform spinelets on apron; c, actinal view showing oral, suboral, furrow and inter-radial spines; d, transverse section of a ray with superactinal (highlighted left) and superambulacral plates (highlighted right).