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Asteroidea taxon detailsRyukuaster onnae Mah, 2007
 255155 (urn:lsid:marinespecies.org:taxname:255155)
accepted
Species
marine,
recent only
Mah, C. (2007). Systematics, phylogeny and historical biogeography of the <i>Pentagonaster</i> clade (Asteroidea: Valvatida: Goniasteridae. <em>Invertebrate Systematics.</em> 21: 311-339., available online at https://doi.org/10.1071/IS06049 [details]
Description Body shape weakly stellate (R/r= 1.3-1.5). Arms short, triangular, disk broad. Armtips upturned.
Abactinal plates flat...
Description Body shape weakly stellate (R/r= 1.3-1.5). Arms short, triangular, disk broad. Armtips upturned. Abactinal plates flat to mildly convex. Some plates, including those on primary circlet and carinal plates are strongly convex. Abactinal plates round to polygonal in outline, becoming irregular adjacent to marginal plate contact. Carinal plate series round to hexagonal. Primary circlet, interradial plates enlarged (approximately twice as large as carinals). Plates with 8-50 (typically 20-30) peripheral granules, quadrate, angular to polygonal in shape, discretely separate from one another, but tightly arranged. Plates smooth, bare but in larger specimens (R>1.5) granules identical to the peripheral granules form additional rows on the plate adjacent to the periphery, becoming very dense, sometimes completely obscuring the plate. These larger sized specimens also sometimes with large nipple-like tubercle sitting centrally on the interradial plates. Fasciolar channels distinct, but shallow. Papular pores single, if present interradially; double on radial regions. Madreporite triangular, commonly bordered by 3 plates. Four plates are present around more rounded madreporites. Marginal plates elongate, swollen, quadrate in outline, decreasing in size distally toward terminal. Fasciolar channels distinctly present between marginal plate series. Peripheral granules, 20-60, quadrate, rectangular to polygonal, irregularly angular. Larger plates with additional, similar granules forming second and third irregular rows on plate surface adjacent to periphery. Superomarginals eight (R<1.7 cm) to ten (in specimens with R>1.7 cm). Superomarginals elongate, swollen, with largest, most swollen interradially, decreasing distally. Superomarginal surface generally bare with one or sometimes more round tubercular granules on plate surface. Often as single tubercles but also as irregular series following from additional peripheral granular rows. Granules coarser becoming more dense on lateral surface of superomarginal plates with occasional distinct tubercle directed laterally or on lateral edge. One to three large tubercular granules present interradially on lateral surface within dense lateral granular covering. Penultimate superomarginals generally smaller, but variably occur as larger plates similar to those interradially. Short, tubercular spine sometimes found on lateral surface of distalmost superomarginal plates. Inferomarginals ten (R<1.7 cm) to 12 (in specimens with R>1.7 cm), slightly less swollen than superomarginals, decreasing in size distally but becoming more swollen adjacent to terminal plate. Short thorny spinelet, sometimes flanked by one or more pointed to rounded granules on lateal to actinolateral edge of inferomarginal plate. Multiple additional granular rows present on lateral and ventral surface of inferomarginal plates becoming densest laterally but more evenly spaced ventrally. One to three large tubercular granules present interradially on lateral surface within dense lateral granular covering, located adjacent to identical large tubercular granule on superomarginal series. Ventral surface of inferomarginal plate bare, but bare area varies with degree of granular expression, which is greater in larger specimens. Intermarginal pits located between the central two to three interradial superomarginal-inferomarginal pairs. The pits are bare but flanked on each corner by three to four clavate spines, each with large rounded tips distributed between the superomarginal and inferomarginal granules. The spines shows fine, roughened surface texture and are covered by tissue in dried specimens. Terminal plate enlarged, rounded, swollen, similar to half the size of adjacent superomarginal plates in smaller (R<1.3 cm) specimens. Two to three short spines present on terminal and sometimes as part of peripheral granule series adjacent to terminal. Actinal plates polygonal with angular edges, flattened in chevron formati [details]
Mah, C.L. (2024). World Asteroidea Database. Ryukuaster onnae Mah, 2007. Accessed at: https://www.marinespecies.org/Asteroidea/aphia.php?p=taxdetails&id=255155 on 2024-04-16
Date action by
original description
Mah, C. (2007). Systematics, phylogeny and historical biogeography of the <i>Pentagonaster</i> clade (Asteroidea: Valvatida: Goniasteridae. <em>Invertebrate Systematics.</em> 21: 311-339., available online at https://doi.org/10.1071/IS06049 [details]
 Present Inaccurate Introduced: alien Containing type locality
From editor or global species database
Description Body shape weakly stellate (R/r= 1.3-1.5). Arms short, triangular, disk broad. Armtips upturned. Abactinal plates flat to mildly convex. Some plates, including those on primary circlet and carinal plates are strongly convex. Abactinal plates round to polygonal in outline, becoming irregular adjacent to marginal plate contact. Carinal plate series round to hexagonal. Primary circlet, interradial plates enlarged (approximately twice as large as carinals). Plates with 8-50 (typically 20-30) peripheral granules, quadrate, angular to polygonal in shape, discretely separate from one another, but tightly arranged. Plates smooth, bare but in larger specimens (R>1.5) granules identical to the peripheral granules form additional rows on the plate adjacent to the periphery, becoming very dense, sometimes completely obscuring the plate. These larger sized specimens also sometimes with large nipple-like tubercle sitting centrally on the interradial plates. Fasciolar channels distinct, but shallow. Papular pores single, if present interradially; double on radial regions. Madreporite triangular, commonly bordered by 3 plates. Four plates are present around more rounded madreporites. Marginal plates elongate, swollen, quadrate in outline, decreasing in size distally toward terminal. Fasciolar channels distinctly present between marginal plate series. Peripheral granules, 20-60, quadrate, rectangular to polygonal, irregularly angular. Larger plates with additional, similar granules forming second and third irregular rows on plate surface adjacent to periphery. Superomarginals eight (R<1.7 cm) to ten (in specimens with R>1.7 cm). Superomarginals elongate, swollen, with largest, most swollen interradially, decreasing distally. Superomarginal surface generally bare with one or sometimes more round tubercular granules on plate surface. Often as single tubercles but also as irregular series following from additional peripheral granular rows. Granules coarser becoming more dense on lateral surface of superomarginal plates with occasional distinct tubercle directed laterally or on lateral edge. One to three large tubercular granules present interradially on lateral surface within dense lateral granular covering. Penultimate superomarginals generally smaller, but variably occur as larger plates similar to those interradially. Short, tubercular spine sometimes found on lateral surface of distalmost superomarginal plates. Inferomarginals ten (R<1.7 cm) to 12 (in specimens with R>1.7 cm), slightly less swollen than superomarginals, decreasing in size distally but becoming more swollen adjacent to terminal plate. Short thorny spinelet, sometimes flanked by one or more pointed to rounded granules on lateal to actinolateral edge of inferomarginal plate. Multiple additional granular rows present on lateral and ventral surface of inferomarginal plates becoming densest laterally but more evenly spaced ventrally. One to three large tubercular granules present interradially on lateral surface within dense lateral granular covering, located adjacent to identical large tubercular granule on superomarginal series. Ventral surface of inferomarginal plate bare, but bare area varies with degree of granular expression, which is greater in larger specimens. Intermarginal pits located between the central two to three interradial superomarginal-inferomarginal pairs. The pits are bare but flanked on each corner by three to four clavate spines, each with large rounded tips distributed between the superomarginal and inferomarginal granules. The spines shows fine, roughened surface texture and are covered by tissue in dried specimens. Terminal plate enlarged, rounded, swollen, similar to half the size of adjacent superomarginal plates in smaller (R<1.3 cm) specimens. Two to three short spines present on terminal and sometimes as part of peripheral granule series adjacent to terminal. Actinal plates polygonal with angular edges, flattened in chevron formati [details] Type designation Type species name in the original description is misspelled "Ryukaster onnae" (the second u is missing-should be "Ryukuaster") and it is herein declared that this WAS only a typo and should not be miscontrued as a legal designation of the type name. [details] |
