Overlooked biodiversity from museum collections: four new species and one new genus of Ophiuroidea (Echinodermata) from Antarctica and adjacent regions with notes on multi-armed ophiuroids

Okanishi, Masanori; Mah, Christopher L.

doi:10.1007/s12526-020-01080-w

Cited by 4 publications

(2 citation statements)

References 27 publications

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“…Some fissiparous species, which usually have six arms, have also been recorded occasionally with seven, including Ophiocomella sexradia (Duncan, 1887) (Ophiacanthida) and various Ophiactis species (Amphilepidida). The presence of 10 or more simple arms has been associated with an arborescent habitat [32].…”

Section: Systematic Taxonomymentioning

confidence: 99%

Relict from the Jurassic: new family of brittle-stars from a New Caledonian seamount

2021

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The deep-seafloor in the tropical Indo-Pacific harbours a rich and diverse benthic fauna with numerous palaeoendemics. Here, we describe a new species, genus and family of brittle-star (Ophiuroidea) from a single eight-armed specimen collected from a depth between 360 and 560 m on Banc Durand, a seamount east of New Caledonia. Leveraging a robust, fossil-calibrated (265 kbp DNA) phylogeny for the Ophiuroidea, we estimate the new lineage diverged from other ophiacanthid families in the Late Triassic or Jurassic (median = 187–178 Myr, 95% CI = 215–143 Myr), a period of elevated diversification for this group. We further report very similar microfossil remains from Early Jurassic (180 Myr) sediments of Normandy, France. The discovery of a new ancient lineage in the relatively well-known Ophiuroidea indicates the importance of ongoing taxonomic research in the deep-sea, an environment increasingly threatened by human activities.

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Section: Systematic Taxonomymentioning

confidence: 99%

Relict from the Jurassic: new family of brittle-stars from a New Caledonian seamount

2021

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“…Although echinoderms are generally viewed as animals with body plans arranged in five rays, axes, or ambulacra, there are groups that have more than five rays. Addition of rays occurs by insertion of new rays between or among the original five rays from the ring canal in some seastars (Asteroidea; Lawrence and Komatsu 1990 ) and some brittlestars (Ophiuroidea; Okanishi and Mah 2020 ). The addition of rays increases the length of usable ambulacra and the podia (tube feet) that line them to magnify the functions of podia for feeding, locomotion, gas exchange, or other roles ( Lawrence 2012 ).…”

Section: Introductionmentioning

confidence: 99%

A Sister-Group Comparison of Branching and Pedicellariae in Brittlestars (Echinodermata: Ophiuroidea)

Turner

O'Neill

2023

Integrative Organismal Biology

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Branching of arms and presence of pedicellariae are characters among ophiuroids found only in the order Euryalida (snakestars and basketstars). Family Asteronychidae has neither character; family Euryalidae has two small clades with branched arms; and family Gorgonocephalidae has all species with pedicellariae and three or four clades with branched arms. Despite the rare occurrence of these characters in the Ophiuroidea, they might be key adaptations within the Euryalida that have led to relatively high diversification. Sister-group comparison of the distribution of these two characters among taxa indicates that neither character alone explains diversity patterns within the order. In particular, branching restricted to the tips of arms seems not strongly adaptive, probably for lack of integration of basal forks with the disc. On the other hand, two clades of gorgonocephalids with basal branching exceed their snakestar sister groups in numbers of species, indicating an advantage of branching within the family. Unfortunately, the analysis cannot benefit from statistics, for at least five independent comparisons are required for a one-tailed sign test. Because branching and pedicellariae are probably not independent variables, future sister-group comparisons should be done only within the Gorgonocephalidae once clade structure is better clarified with increased taxon sampling (10 currently missing genera) and resolution of intra-generic inconsistencies in the most recent cladograms available. Branching might confer upon gorgonocephalid basketstars a more efficient use of pedicellariae for upstream capture of zooplankton over their snakestar relatives as well as over the Euryalidae, which retain ancestral downstream capture by mucus-laden podia.

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Taxonomy and distribution of deep benthos collected in and around the Southern Ocean during the 30th Anniversary expeditions of R/V Hakuho Maru: Annelida, Mollusca, Ostracoda, Decapoda, and Echinodermata

et al. 2022

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Overlooked biodiversity from museum collections: four new species and one new genus of Ophiuroidea (Echinodermata) from Antarctica and adjacent regions with notes on multi-armed ophiuroids

Cited by 4 publications

References 27 publications

Relict from the Jurassic: new family of brittle-stars from a New Caledonian seamount

Relict from the Jurassic: new family of brittle-stars from a New Caledonian seamount

A Sister-Group Comparison of Branching and Pedicellariae in Brittlestars (Echinodermata: Ophiuroidea)

Taxonomy and distribution of deep benthos collected in and around the Southern Ocean during the 30th Anniversary expeditions of R/V Hakuho Maru: Annelida, Mollusca, Ostracoda, Decapoda, and Echinodermata

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