Pseudonepanthia A.H. Clark, 1916

O’Loughlin, P. Mark & Waters, Jonathan M., 2004, A molecular and morphological revision of genera of Asterinidae (Echinodermata: Asteroidea), Memoirs of Museum Victoria 61 (1), pp. 1-40 : 32-33

Pseudonepanthia A.H. Clark

Figures 1 , 3c , 4e , 5d , 14d–f

Pseudonepanthia A.H. Clark, 1916: 118 .—A.M. Clark, 1993: 227.

Diagnosis. Rays 4–10, subcylindrical, not flat actinally, lacking marginal edge; integument variably noticeable; lacking secondary plates; abactinal spinelets thick or thin or subsacciform, covering plates or in tufts; lacking pedicellariae; plates lacking glassy convexities; inferomarginal plates not projecting; furrow spines up to 5 per plate; actinal interradial spines digitiform, up to 7–30 per plate; series of superambulacral plates present, rare transactinal plates; lacking superactinal plates.

Type species. Pseudonepanthia gotoi A.H. Clark, 1916 (original designation).

Other species. P. briareus (Bell, 1894) ; P. gracilis ( Rowe and Marsh, 1982) ; P. grangei (McKnight, 2001) (in Clark and McKnight); P. nigrobrunnea ( Rowe and Marsh, 1982) ; P. reinga (McKnight, 2001) (in Clark and McKnight); P. troughtoni (Livingstone, 1934) .

Material examined. P. briareus . Mariana Is , Guam, 118–152 m, UF 226 (1).

Pseudonepanthia gotoi . Holotype. Japan, Sagami Bay , 90 m, USNM 36899 .

P. gracilis . Australia, New South Wales, AM J12874 (2) ; J11880 (2).

P. nigrobrunnea . New South Wales, Coffs Harbour, NMV F95810 (2); Byron Bay, F95804 (1).

Parasterina troughtoni . Holotype. Western Australia, Albany , AM J3978 . Other material. Victoria, Cape Woolamai, NMV F73013 (1); Wilsons Promontory, F73017 (1); South Australia, Cape Jervis, F73977 (4) .

Description with species variations. Rays 4–10, distinct, elongate, subcylindrical, tapered slightly ( nigrobrunnea , troughtoni ) or strongly ( briareus , gotoi , gracilis , grangei , reinga ), some irregular ( briareus , gotoi , nigrobrunnea ); integument variably noticeable; margin rounded, rays not flat actinally, lacking marginal edge; size large ( troughtoni up to R = 87 mm) to medium ( grangei up to R = 33 mm); lacking pedicellariae; gonopores sometimes actinal ( troughtoni ); one fissiparous ( briareus ).

Abactinal plates imbricating, projecting proximal edge creating uneven surface, irregular in form and arrangement on upper rays, oblique longitudinal series along sides of rays; lacking secondary plates; papulate areas extending to near margin; papular spaces with single large papula or a few ( nigrobrunnea ); abactinal plates with spinelet-bearing elevations or not ( troughtoni ); spinelets glassy, subsacciform with splayed points distally ( briareus , gotoi ), or subsacciform ( gracilis ), or fine columnar ( nigrobrunnea , troughtoni ); spinelets covering plates closely ( gotoi , gracilis , nigrobrunnea , troughton i) or in splayed groups ( briareus ); disc not bordered; cleared plates lacking glassy convexities; superomarginal plates in regular or irregular series; marginal plates covered with abactinal type spinelets; inferomarginal plates in predominantly regular series, frequently longitudinally elongate, not projecting.

Actinal plates with spine-bearing elevations or not ( troughtoni ); not in oblique series.

Actinal spines per plate: oral 3–10; suboral 4–12; furrow 3–5; subambulacral 6–10; actinal 7–30; adradial row of actinal plates with complete series of spines; interradial actinal spines digitiform.

Superambulacral plates present as predominantly single series along ambulacrum, sometimes contiguous with inferomarginal plates across floor of ray ( briareus , troughtoni ) or with abactinal plates ( nigrobrunnea ); rare transactinal plates (sometimes irregularly present in gracilis ); lacking superactinal plates; interior of rays with resinous lining.

Distribution. Mariana Is, SE Japan, South China Sea, Philippines, E Indonesia, E and S Australia, New Zealand; 0– 540 m.

Remarks. Molecular data are available for P. troughtoni only. This review is based on morphology. Six species are removed from Nepanthia to Pseudonepanthia which is distinguished by: rays not flat actinally, lacking a marginal edge; absence of secondary plates, pedicellariae and glassy convexities; furrow spines fewer than 6 per plate; absence of transactinal and superactinal plates.

McKnight (in Clark and McKnight, 2001) referred Nepanthia grangei and N. reinga “provisionally” to Nepanthia . Material has not been examined, and internal skeletal plates not observed. Based on the descriptions, the absence of secondary plates and pedicellariae, and presence of up to five furrow spines per plate, fit the diagnosis of Pseudonepanthia to which both species are reassigned.

Figures

Figure 1. Phylogenetic relationships of asterinid mtDNA sequences (after Waters et al., 2004). Support for particular reconstructions is indicated by bootstrap values (>50%; in bold) and by decay indices (in italics). MtDNA Clades I–VI are identified on the basis of high bootstrap support. Generic assignments made in this paper appear on the right.

Figure 3. Abactinal views of type species of Asterinidae genera (continued; Tremaster mirabilis is figure 17e). a, Patiria miniata (R = 67 mm, NMV F98040). b, Patiriella regularis (R = 31 mm, AM J5594). c, Pseudonepanthia gotoi (R = 74 mm, holotype, USNM 36899). d, Pseudopatiria obtusa (R = 54 mm, holotype, BMNH 1938.6.23.24). e, Stegnaster inflatus (R = 45 mm, NMV F95675). f, Tegulaster emburyi (R = 19 mm, holotype, AM J5605).

Figure 4. Abactinal views, with plates removed and cleared with bleach to show internal morphology. a–b, Parvulastra dyscrita (R = 24 mm, TM H854): a, series of superambulacral plates linking ambulacral and actinal plates; b, superactinal plates linking abactinal and actinal plates to support the interradial margin. c, Meridiastra oriens (R = 28 mm, NMV F73468): margin supported by internal contiguous projections of abactinal and actinal plates (arrow), absence of superambulacral and superactinal plates. d, Patiria miniata (R = 65 mm, NMV F97444): multiple superactinal plate struts supporting interradial margin. e, Pseudonepanthia troughtoni (R = 85 mm, NMV F73013): series of superambulacral plates, and thick internal tisue lining. f, Nepanthia belcheri (R = 40 mm, NMV F95806): transactinal plates extending transversely across actinal inner ray, and thick internal tissue lining.

Figure 5. Forms of spinelets and spines. a, Meridiastra gunnii (NMV F73248): granuliform abactinal spinelets. b, Parvulastra dyscrita (TM H854): globose abactinal spinelets. c, Paranepanthia grandis (NMV F73976): acicular abactinal spinelets. d, Pseudonepanthia gotoi (USNM 36899): splay-pointed abactinal spinelets. e, Parvulastra dyscrita (TM H854): digitiform actinal spines. f, Disasterina longispina (WAM Z6760): sacciform actinal spines.

Figure 14. a–c, Nepanthia pedicellaris (R = 23 mm, holotype, USNM 32643): a, cleared lower lateral ray, and distinct margin; b, abactinal spinelets; c, adambulacral and actinal plates and spines. d, Pseudonepanthia troughtoni (R = 55 mm, NMV F73977): cleared proximal lateral lower ray, margin, and ambulacrum. e, Pseudonepanthia nigrobrunnea (R = 85 mm, NMV F95810): cleared section of ray with single series of superambulacral plates (arrow), and absence of transactinal and superactinal plates. f, Pseudonepanthia gotoi (R = 70 mm, holotype, USNM 36899): internal cleared view of ambulacral plates, with series of superambulacral plates (arrow).