Paranepanthia Fisher, 1917

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 : 25-27

Paranepanthia Fisher

Figures 1 (clade I), 2k, 5c, 15a–c

Paranepanthia Fisher, 1917: 172 .— Fisher, 1919: 419.—H.L. Clark, 1946: 136.— Spencer and Wright, 1966: U69.—A.M. Clark, 1993: 222.— Rowe, 1995: 39.—McKnight (in Clark and McKnight), 2001: 160.— Waters et al., 2004: 874, 875, 877.

Diagnosis. Rays 5, medium length, wide basally, pointed or rounded distally; flat actinally, rays elevated to low; abactinal and actinal interradial plates with subpaxilliform dense clusters of acicular subsacciform spinelets; abactinal plates mostly irregular on upper rays, mostly series perpendicular to margin in interradii; marginal plates subequal, in regular series, with dense tufts of spinelets, inferomarginals project prominently; actinal interradial plates in oblique series; superambulacral plates absent; superactinal plates present as multiple struts.

Type species. Nepanthia platydisca Fisher, 1913 (original designation).

Other species. P. aucklandensis ( Koehler, 1920) ; P. grandis (H.L. Clark, 1928) (junior synonym Asterinopsis praetermissa Livingstone, 1933 , by Rowe, 1995).

Material examined. P. aucklandensis . New Zealand, Auckland I., AM J5160 (2) ; J6023 (1).

Asterinopsis praetermissa . Holotype. Australia, New South Wales, Port Jackson , AM J4793 .

Nepanthia platydisca . Holotype. Indonesia, 377 m, USNM 32644 .

P. grandi s. Australia, Victoria, NMV F72887 (1); Bass Strait, F 98044 (1) ; South Australia, F73976 (4).

Description with species variations. Rays 5, interradial margin deeply incurved, rays distinct, ends of rays rounded ( aucklandensis , grandis ) or pointed ( platydisca ); body flat actinally, rays elevated or low ( platydisca ); distal interradial body thin (actinal to abactinal) or not ( aucklandensis ), area of non-papulate plates wide or not ( aucklandensis ); size medium ( grandis up to R = 65 mm) to small ( aucklandensis up to R = 22 mm); lacking pedicellariae; none fissiparous; gonopores abactinal.

Abactinal plates imbricate, distinct radial and interradial ‘fields’, plates on upper rays irregular in size, shape, arrangement (except aucklandensis with regular proximal carinal and upper ray series, and crescentiform plates), up to 3 fairly irregular longitudinal series along each side of rays; papular spaces large, with numbers of small papulae, variable numbers of secondary plates; interradial series of small plates perpendicular to margin (except longitudinal series in aucklandensis ); disc not bordered or variably bordered ( aucklandensis ); abactinal plates with high ( grandis ) or low ( aucklandensis , platydisca ) spinelet-bearing domes or ridges; glassy convexities on plates present ( aucklandensis ) or not ( grandis , platydisca ); subpaxilliform tufts of many acicular subsacciform spinelets; superomarginal and inferomarginal plates in distinct series, subequal; both series with spinelet-bearing domes and subpaxilliform dense tufts of acicular spinelets; inferomarginals define acute margin, projecting plates with narrowed waist ( aucklandensis , grandi s) or not ( platydisca ).

Actinal plates in oblique series; plates with high ( grandis , platydisca ) or low ( aucklandensis ) spine-bearing domes.

Actinal spines per plate: oral 8–12; suboral tufts or transverse series; furrow 7–10, webbed; subambulacral dense tufts; adradial and actinal interradial dense subpaxilliform tufts (up to about 40 spines); actinal interradial spines acicular subsacciform.

Lacking superambulacral plates; numerous superactinal plates in multiple plate struts; distal interradial margin supported by angled contiguous abactinal and actinal plates ( grandis , platydisca ), lacking internal projections (except aucklandensis with internal tongue-like projections from abactinal plates).

Distribution. E and S Australia, Indonesia, subantarctic New Zealand; 0– 377 m.

Remarks. Three species cluster together in clade I of Waters et al. (2004). One of these is a species that has been assigned to Paranepanthia in the past and one is undescribed. The molecular evidence that Asterina aucklandensis is also a member of this clade is supported by morphological criteria. All three species of Paranepanthia were examined and the morphological integrity of the genus confirmed. Paranepanthia is characterised by the unique combination of subpaxilliform dense clusters of acicular spines and spinelets on the plates, absence of superambulacral plates, and presence of superactinal plates. Paranepanthia rosea has been removed to Aquilonastra .

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.