Inexpectacantha Thuy 2011
Genus Inexpectacantha Thuy, 2011 Type species Inexpectacantha acrobatica Thuy, 2011, by original designation. Diagnosis Ophiacanthid with small to moderately large LAPs of thick, massive and generally bulging aspect; outer surface devoid of conspicuous ornament; no spurs on outer proximal and inner...
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Online Access: | https://dx.doi.org/10.5281/zenodo.3844117 https://zenodo.org/record/3844117 |
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DataCite Metadata Store (German National Library of Science and Technology) |
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Biodiversity Taxonomy Animalia Echinodermata Ophiuroidea Ophiurida Ophiacanthidae Inexpectacantha |
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Biodiversity Taxonomy Animalia Echinodermata Ophiuroidea Ophiurida Ophiacanthidae Inexpectacantha Thuy, Ben Inexpectacantha Thuy 2011 |
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Biodiversity Taxonomy Animalia Echinodermata Ophiuroidea Ophiurida Ophiacanthidae Inexpectacantha |
description |
Genus Inexpectacantha Thuy, 2011 Type species Inexpectacantha acrobatica Thuy, 2011, by original designation. Diagnosis Ophiacanthid with small to moderately large LAPs of thick, massive and generally bulging aspect; outer surface devoid of conspicuous ornament; no spurs on outer proximal and inner distal edges; small, earshaped spine articulations freestanding or in shallow depressions of bulging distal portion of LAP; spine articulations commonly tilted; ventral lobe rugged to irregularly corrugate, commonly confluent with outer surface stereom; spine articulations not sharply bordered proximally and with dorsalward increase in size; short, broad, dorso-proximalwards bent, tongue-shaped ridge devoid of kinks or widened parts; tentacle notch very small, poorly defined. Remarks Inexpectacantha acrobatica is probably one of the best-known fossil ophiuroids. In fact, the original description was based on outstandingly well-preserved material from the Pliensbachian of France, comprising both articulated skeletons and dissociated skeletal parts, including LAPs, allowing for a morphological analysis of exceptional detail (Thuy 2011).As a result, fossil dissociated LAPs compatible with the LAP morphological diagnosis of Inexpectacantha are unambiguously identifiable and thus provide evidence for bracketing the divergence time of the genus. The LAPs of Inexpectacantha are among the most characteristic of all ophiacanthid LAP types. In fact, the a massive, thick, round and bulging general aspect, the lack of conspicuous outer surface ornament and spurs on the outer proximal and inner distal edges, small spine articulations with dorsalward increase in size and not bordered proximally by a ridge, a large, broad, tongue-shaped ridge devoid of kinks, extensions or strongly widened parts on the inner side, and very small, poorly defined tentacle notches are a combination of characters not found in any other ophiacanthid genus. Superficial similarities are shared with the LAPs of Ophiochondrus Lyman, 1869, in which, however, the spine articulations are generally not oblique and not confluent with the outer surface stereom. In addition, the LAPs of Ophiochondrus are less massive, and the ridge on the inner side displays a ventro-proximalwards projecting extension. Greatest similarities are shared with the LAPs of Ophioleviathan gen. nov. (see below), particularly with respect to the massive and thick general aspect, and the shape of the spine articulations and of the ridge on the inner side. The LAPs of Ophioleviathan gen. nov., however, are significantly larger than those of Inexpectacantha and display larger, near-vertical spine articulations in deeper notches and composed of distal and proximal rather than dorsal and ventral lobes, with a strongly thickened distal lobe. Nevertheless, as discussed below, the LAP morphologies of both genera as so similar that they most likely represent sister taxa. Interestingly, the currently known species of Inexpectacantha fall into two groups on the basis of LAP morphology: I. ritae sp. nov. and I. lunaris (Hess, 1962), plus I. weisi sp. nov. and I. acrobatica . The two last named are characterised by generally smaller LAPs with smaller height/width ratios, spine articulations freestanding rather than in notches, a more coarsely meshed stereom on the outer surface, and lip-shaped distal knobs in the spine articulations of the distal LAPs. Most of these characters are typically indicative of a paedomorphic condition (Stöhr 2005, 2011). Indeed, the articulated specimens of Inexpectacantha acrobatica display a strikingly paedomorphic general morphology (Thuy 2011). : Published as part of Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), pp. 1-242 in European Journal of Taxonomy 48 on pages 185-186, DOI: 10.5852/ejt.2013.48, http://zenodo.org/record/3822836 : {"references": ["Hess H. 1962. Mikropalaontologische Untersuchungen an Ophiuren II: Die Ophiuren aus dem Lias (Pliensbachien-Toarcien) von Seewen (Kt. Solothurn). Eclogae geologicae Helvetiae 55: 609 - 656.", "Stohr S. 2005. Who's who among baby brittle stars (Echinodermata, Ophiuroidea): postmetamorphic development of some North Atlantic forms. Zoological Journal of the Linnean Society 143 (4): 543 - 576. http: // dx. doi. org / 10.1111 / j. 1096 - 3642.2005.00155. x"]} |
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Text |
author |
Thuy, Ben |
author_facet |
Thuy, Ben |
author_sort |
Thuy, Ben |
title |
Inexpectacantha Thuy 2011 |
title_short |
Inexpectacantha Thuy 2011 |
title_full |
Inexpectacantha Thuy 2011 |
title_fullStr |
Inexpectacantha Thuy 2011 |
title_full_unstemmed |
Inexpectacantha Thuy 2011 |
title_sort |
inexpectacantha thuy 2011 |
publisher |
Zenodo |
publishDate |
2013 |
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https://dx.doi.org/10.5281/zenodo.3844117 https://zenodo.org/record/3844117 |
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ENVELOPE(-65.133,-65.133,-67.200,-67.200) |
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Hess |
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Hess |
genre |
North Atlantic |
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North Atlantic |
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http://zenodo.org/record/3822836 http://publication.plazi.org/id/6541EF1B6555857BD1302529FFF89F78 http://zoobank.org/E7080722-E348-448D-96E5-D537F4865BB5 https://zenodo.org/communities/biosyslit https://dx.doi.org/10.5852/ejt.2013.48 http://zenodo.org/record/3822836 http://publication.plazi.org/id/6541EF1B6555857BD1302529FFF89F78 http://zoobank.org/E7080722-E348-448D-96E5-D537F4865BB5 https://dx.doi.org/10.5281/zenodo.3844116 https://zenodo.org/communities/biosyslit |
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Open Access Creative Commons Zero v1.0 Universal https://creativecommons.org/publicdomain/zero/1.0/legalcode cc0-1.0 info:eu-repo/semantics/openAccess |
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https://doi.org/10.5281/zenodo.3844117 https://doi.org/10.5852/ejt.2013.48 https://doi.org/10.5281/zenodo.3844116 |
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ftdatacite:10.5281/zenodo.3844117 2023-05-15T17:37:30+02:00 Inexpectacantha Thuy 2011 Thuy, Ben 2013 https://dx.doi.org/10.5281/zenodo.3844117 https://zenodo.org/record/3844117 unknown Zenodo http://zenodo.org/record/3822836 http://publication.plazi.org/id/6541EF1B6555857BD1302529FFF89F78 http://zoobank.org/E7080722-E348-448D-96E5-D537F4865BB5 https://zenodo.org/communities/biosyslit https://dx.doi.org/10.5852/ejt.2013.48 http://zenodo.org/record/3822836 http://publication.plazi.org/id/6541EF1B6555857BD1302529FFF89F78 http://zoobank.org/E7080722-E348-448D-96E5-D537F4865BB5 https://dx.doi.org/10.5281/zenodo.3844116 https://zenodo.org/communities/biosyslit Open Access Creative Commons Zero v1.0 Universal https://creativecommons.org/publicdomain/zero/1.0/legalcode cc0-1.0 info:eu-repo/semantics/openAccess CC0 Biodiversity Taxonomy Animalia Echinodermata Ophiuroidea Ophiurida Ophiacanthidae Inexpectacantha Text Taxonomic treatment article-journal ScholarlyArticle 2013 ftdatacite https://doi.org/10.5281/zenodo.3844117 https://doi.org/10.5852/ejt.2013.48 https://doi.org/10.5281/zenodo.3844116 2021-11-05T12:55:41Z Genus Inexpectacantha Thuy, 2011 Type species Inexpectacantha acrobatica Thuy, 2011, by original designation. Diagnosis Ophiacanthid with small to moderately large LAPs of thick, massive and generally bulging aspect; outer surface devoid of conspicuous ornament; no spurs on outer proximal and inner distal edges; small, earshaped spine articulations freestanding or in shallow depressions of bulging distal portion of LAP; spine articulations commonly tilted; ventral lobe rugged to irregularly corrugate, commonly confluent with outer surface stereom; spine articulations not sharply bordered proximally and with dorsalward increase in size; short, broad, dorso-proximalwards bent, tongue-shaped ridge devoid of kinks or widened parts; tentacle notch very small, poorly defined. Remarks Inexpectacantha acrobatica is probably one of the best-known fossil ophiuroids. In fact, the original description was based on outstandingly well-preserved material from the Pliensbachian of France, comprising both articulated skeletons and dissociated skeletal parts, including LAPs, allowing for a morphological analysis of exceptional detail (Thuy 2011).As a result, fossil dissociated LAPs compatible with the LAP morphological diagnosis of Inexpectacantha are unambiguously identifiable and thus provide evidence for bracketing the divergence time of the genus. The LAPs of Inexpectacantha are among the most characteristic of all ophiacanthid LAP types. In fact, the a massive, thick, round and bulging general aspect, the lack of conspicuous outer surface ornament and spurs on the outer proximal and inner distal edges, small spine articulations with dorsalward increase in size and not bordered proximally by a ridge, a large, broad, tongue-shaped ridge devoid of kinks, extensions or strongly widened parts on the inner side, and very small, poorly defined tentacle notches are a combination of characters not found in any other ophiacanthid genus. Superficial similarities are shared with the LAPs of Ophiochondrus Lyman, 1869, in which, however, the spine articulations are generally not oblique and not confluent with the outer surface stereom. In addition, the LAPs of Ophiochondrus are less massive, and the ridge on the inner side displays a ventro-proximalwards projecting extension. Greatest similarities are shared with the LAPs of Ophioleviathan gen. nov. (see below), particularly with respect to the massive and thick general aspect, and the shape of the spine articulations and of the ridge on the inner side. The LAPs of Ophioleviathan gen. nov., however, are significantly larger than those of Inexpectacantha and display larger, near-vertical spine articulations in deeper notches and composed of distal and proximal rather than dorsal and ventral lobes, with a strongly thickened distal lobe. Nevertheless, as discussed below, the LAP morphologies of both genera as so similar that they most likely represent sister taxa. Interestingly, the currently known species of Inexpectacantha fall into two groups on the basis of LAP morphology: I. ritae sp. nov. and I. lunaris (Hess, 1962), plus I. weisi sp. nov. and I. acrobatica . The two last named are characterised by generally smaller LAPs with smaller height/width ratios, spine articulations freestanding rather than in notches, a more coarsely meshed stereom on the outer surface, and lip-shaped distal knobs in the spine articulations of the distal LAPs. Most of these characters are typically indicative of a paedomorphic condition (Stöhr 2005, 2011). Indeed, the articulated specimens of Inexpectacantha acrobatica display a strikingly paedomorphic general morphology (Thuy 2011). : Published as part of Thuy, Ben, 2013, Temporary expansion to shelf depths rather than an onshore-offshore trend: the shallow-water rise and demise of the modern deep-sea brittle star family Ophiacanthidae (Echinodermata: Ophiuroidea), pp. 1-242 in European Journal of Taxonomy 48 on pages 185-186, DOI: 10.5852/ejt.2013.48, http://zenodo.org/record/3822836 : {"references": ["Hess H. 1962. Mikropalaontologische Untersuchungen an Ophiuren II: Die Ophiuren aus dem Lias (Pliensbachien-Toarcien) von Seewen (Kt. Solothurn). Eclogae geologicae Helvetiae 55: 609 - 656.", "Stohr S. 2005. Who's who among baby brittle stars (Echinodermata, Ophiuroidea): postmetamorphic development of some North Atlantic forms. Zoological Journal of the Linnean Society 143 (4): 543 - 576. http: // dx. doi. org / 10.1111 / j. 1096 - 3642.2005.00155. x"]} Text North Atlantic DataCite Metadata Store (German National Library of Science and Technology) Hess ENVELOPE(-65.133,-65.133,-67.200,-67.200) |