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Hlavní autor:	Mah, Christopher L.
Médium:	Recurso digital
Jazyk:
Vydáno:	Zenodo 2026
Témata:	Biodiversity Taxonomy Animalia Echinodermata Asteroidea Valvatida Goniasteridae Nymphaster Nymphaster defensor
On-line přístup:	https://doi.org/10.5281/zenodo.20318397
Tagy:	Přidat tag Žádné tagy, Buďte první, kdo vytvoří štítek k tomuto záznamu!

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Nymphaster defensor sp. nov.FIGURE 31A–FEtymologyThe species epithet is derived from the Latin defendo, for guard or protect alluding to the marginal spines and the well-developed size and skeleton of this species.DiagnosisAbactinal plates with smooth, round to polygonal granules, 1 to 40, mostly 7 to 30, on central surface of most plates with approximately 9 to 25 forming evenly spaced periphery around plate edge. Marginal plates with sharply angular edges. Spines on abactinal-lateral, actino-lateral edges of supero- and inferomarginal plates. Furrow spines 8 to 10, mostly 9 or 10 at R=13.0. Subambulacral spines in three well-spaced series, the first sits adjacent the furrow spines, and are twice in thickness but similar in height to the furrow spines, with two to four spine-tipped granules or spines in each series set off by distinct space from the furrow space. Oral plates with 10 furrow spines.CommentsThis species shares several characters with Nymphaster moluccanus Fisher 1913 as described from the Molucca Islands (Fisher 1913, 1919). Furrow spines on the adambulacral and mouth plates are nearly identical, as well as the number of free superomarginals in contact with the disk and overall appearance of the superomarginal plates along the arms. Significant differences in Nymphaster sp. nov. include the presence of 1 to 4 spines on the abactinal/actinal-lateral edges along the superomarginal and inferomarginal plates on the disk and arms (Fig. 31C). Abactinal radial plates are distinctly hexagonal (Fig. 31B) versus those in the type, which are rounder and more polygonal. Subambulacral spines in the smaller specimen (MNHN IE-2013-6981), R=8.7 similar in height to original description, but only 2 rows of granules were present, versus 3 in the type. The larger, MNHN IE-2013-6980, R=12.0 had 4 subambulacral spines which larger and thicker, with spines up to 2 to 3x the thickness of the furrow spines, one or two prominent pedicellariae per plate and only a single row of granules, which differs significantly from Fisher’s description.While there are very distinct and apparent differences in these specimens, it should be noted that a wide range of variation has been argued for the Atlantic Nymphaster arenatus. One of N. arenatus ’ synonyms, N. subspinosus (Perrier, 1881) was distinguished based on the presence of spines on its marginal plates but was subsequently synonymized (Halpern, 1970; Clark & Downey 1992). However, as phylogenetic methods have been applied towards understanding of wide-ranging asteroid species, it has become clear that widely occurring species, such as Hippasteria phrygiana and other Hippasteria species can display highly variable morphologies but are not always associated with distinct species and conversely, distinct species can be differentiated by relatively few characters (e.g. H. muscipula, Foltz et al. 2013; Mah et al. 2014).Thus, the characters observed here could distinguish a separate species or could simply indicate variation in a wide-ranging N. moluccana, in a similar fashion to N. arenatus. Further testing of the population, further specimens, and character variation in these wide-ranging species is desirable.Distribution/OccurrenceNew Caledonia, 420–863 mFiji and Vanuatu, 420–1050 m.DescriptionBody thick, strongly stellate (R/r=3.1–3.9), arms sharply tapering, triangular in shape with pointed arm tips, trapezoid in cross-section. Interradial arcs weakly curved (Fig. 31A, E).Abactinal region forming distinct star-shaped region on disk, with distinct superomarginal frame, abactinal plates absent from all but basal regions along arm. Abactinal plates in approximately six rows, distinctly polygonal to hexagonal in outline along radial regions with interradial regions displaying plates in quadrate outline. Abactinal plates with smooth, round granules, 1 to 40, mostly 7 to 30, on central surface of most plates with approximately 9 to 25 forming evenly spaced periphery around plate edge. Granules approximately 3 along a 1.0 mm line, widely spaced (Fig. 31B). Granules on abactinal plates variably wide to closely arranged in curved or linear series. Papulae present along with shallow fasciolar grooves on radial disk regions. Central radial regions wide and hexagonal with adradials becoming more polygonal and quadrate in shape adjacent to interradial plates. Papulae and fascicles absent interradially with quadrate interradial plates in close-set formation. Pedicellariae elongate with rounded forceps-like tips, occurring widely across abactinal surface on both radial and interradial plates. Madreporite polygonal with well-developed sulci, flanked by five or more plates.Marginal plates, strongly block-like, approximately 36 (at R= 4.1) to 70 per interradius (arm tip to arm tip at R=13.1) for each series (superomarginal & inferomarginals). Approximately 30 of these superomarginals abutted along mid radius along arm. Abutted superomarginals offset from one another forming zig-zag contact along the abactinal surface on the arm. Superomarginals wide interradially becoming elongate distally along arms. On disk, free superomarginals (non-abutted) number 9 to 10 at R= 13.1 cm. Abactinal-lateral edge along superomarginal plates rounded but very distinct. Inferomarginal series broadly jutting out from under the superomarginal series forming extended periphery (Fig. 31C). Lateral surface well developed forming sloped edge from abactinal to actinolateral surface. Marginal plate surface covered round, coarse deciduous granules, 200–800, widely spaced, approximately 3 granules counted along a 1.0 mm line. Peripheral granules, approximately 20 on shorter edge in contact with abactinal/actinal surface, 30–40 on elongate edge, forming distinct series from those on central plate surface. Spines, 1 to 3, mostly 2, present along abactinal-lateral edge along superomarginal plates. In larger individuals (R>13.0) one or two sharp, conical spines variably present on inferomarginals especially along actinolateral edge with the higher number present centrally per interradius (Fig. 31C). Spines appear variable, as one of the specimens, MNHN IE-2013-1905 lacks inferomarginal spines Smaller individuals, R=4.1, lack spines on inferomarginals. Pedicellariae, one or two similar to those observed on abactinal surface, sitting in shallow alveolar pits, present on actinal-facing surface of distal inferomarginal plates. Terminal plate triangular, smooth with no accessories.Actinal plates in three complete chevron-like series, with each plate in quadrate to polygonal outline (Fig. 31D, E, F). One or two irregular series present in contact distal with inferomarginal contact. Each plate covered by round, evenly distribute4d granules, 10–40, mostly 15 to 30 per surface. Pedicellariae variably present, one individual lacks them versus the holotype with ten pedicellariae present per interradius occurring primarily on the actinal plate series adjacent to the adambulacrals.Furrow spines nine or ten (at R=13.1), numbering eight at R=4.1, blunt tipped, rounded edges, quadrate in cross-section, arranged in concave, variable from nearly straight to strongly angular series.Subambulacral spines in three well-spaced series, the first sits adjacent the furrow spines, and are twice in thickness but similar in height to the furrow spines, with two to four spine-tipped granules or spines in each series set off by distinct space from the furrow space (fig. 31D, F). Adambulacral plates surfaces with two additional series of short spiny granules, shorter than the subambulacral spines.Oral plates with ten blunt furrow spines, round to triangular in cross-section (Fig. 31D). One enlarged spine rom each plate projects into mouth. Oral plate surface with four, blunt subambulacral spines, triangular in cross-section, decreasing in size distally along plate. Oral plate with discrete smooth bald area behind proximalmost oral spines, each followed by four spines, triangular to round in cross section, present along distance of oral plate.Color in life is deep-rich orange.Material ExaminedHolotype. MNHN IE-2013-6980, East coast, New Caledonia, 21º 13'45"S 165º55'1"E, 515–580 m, Coll. BATHUS 1, Bouchet & Richer aboard N/O Alis, CP 658, 12 March 1993. 1 dry spec. R =12.0 r=3.3.Paratypes. New Caledonia. MNHN IE-2013-6981. East coast, New Caledonia, 20°34'S, 165°34.7'E, 591– 660 m. Coll. Bouchet & Richer de Forges, ORSTOM, 18 March 1993, 1 dry specs. R =8.7 r=2.5.MNHN IE-2013-9305 New Caledonia, 22°50'S, 167°18'E to 22°53'S, 167°17'E, 530–545 m. Coll. KANACONO DW 4666, 12.8.16. 1 wet spec. R =12.1 r=3.3.MNHN IE-2013-9746 New Caledonia, 21°16'S, 159°18'E to 21°16'S, 159°16'E, 490–830 m. Coll. KANADEEP, CP 5013, 20.09.17. 2 wet specs. R=12.1, r=3.1(3 arms broken); R=4.1 r=1.3.MNHN IE-2013-9763, New Caledonia, 23°54'S, 161°46'E to 23°57'S, 161°47'E, 980–1050 m. Coll. KANADEEP 5000, 179.17. 1 wet spec. R=9.7 r=2.3.MNHN IE-2013-9756 New Caledonia 21°3'S, 161°8'E to 21°2'S, 161°11'E, 810–840 m. Coll. KANADEEP 5054, 24.09.17. 4 wet specs. R=6.6 r=1.9 R=5.6 r=2.9, R=5.7 r=1.7; R=7.9 r=2.1.MNHN IE-2007-6417. New Caledonia, 21°46'S, 166°44'E, 574– 585 m. Coll. EXBODI CP 3817, 6.9.11. 4 wet specs. R=5.3 r=1,7, R=5.2 r=1.6 R=1.9 r=0.7 R=1.8 r=0.5.MNHN IE-2007-6364, New Caledonia, 22°15'S, 167°19'E, 750– 863 m. Coll., EXBODI, CP 3791, 3.09.11. 15 wet specs (3 examined). R=6.0 r=1.9 R=4.8 r=1.7 R=3.7 r=1.2.Vanuatu. MNHN-IE-2013-6985. Vanuatu, 16º39'S 168º03'E, 469–525 m. Coll. Bouchet & Richer de Forges, N /O Alis, MUSORSTOM 8, CP 1049, 1 Oct 1994. 1 dry spec, R =11.7 r=3.0.Fiji. MNHN IE-2013-6982. Fiji, 16º45'S 179º59'E, 420–513 m. Coll. Bouchet, Waren & Richer de Forges, N //O Alis, BORDAU 1, 4 March 199. 2 dry specs. R =8.5 r=2.6; R=11.5 r=3.4. (specimens broken)

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