Ontogeny and morphology of Cambrian eocrinoid Akadocrinus (Barrandian area, Czech Republic)

Nohejlová, Martina; Fatka, Oldřich

doi:10.3140/bull.geosci.1583

Cited by 9 publications

(2 citation statements)

References 18 publications

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“…The occurrence of morphologically distinct, successive ontogenetic stages has already been seen in some solutans (see, e.g., Noailles et al, 2014). Comparable allometries have been also documented in other Palaeozoic echinoderms, such as eocrinoids (Parsley, 2012;Nohejlováand Fatka, 2016) and stylophorans (Lefebvre et al, 2022). In this interpretation, the unusual morphology of the Z-F24 solutans simply results from their larger size, and all specimens can be assigned to P. mobilis.…”

Section: Systematic Palaeontologymentioning

confidence: 70%

Solutan echinoderms from the Fezouata Shale Lagerstätte (Lower Ordovician, Morocco): diversity, exceptional preservation, and palaeoecological implications

Dupichaud,

Lefebvre,

Milne

et al. 2023

Front. Ecol. Evol.

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In the Lower Ordovician of Morocco, solutan echinoderms are relatively common, locally abundant, geographically widespread (Central and Eastern Anti-Atlas), and biostratigraphically long-ranging (late Tremadocian–mid Floian) components of the Fezouata Biota. The lower part of the Fezouata Shale (late Tremadocian) yielded one specimen, here tentatively identified as a Castericystis-like syringocrinid, with exceptionally preserved internal soft parts presumably corresponding to the distal region of the gut. Most solutan remains from the Fezouata Shale are assigned to Plasiacystis mobilis, which was already known from the late Tremadocian of France and the Darriwilian of the Czech Republic and United Kingdom. Several isolated dististeles provisionally identified as Plasiacystis sp. may belong to large individuals of P. mobilis or a new taxon. Several specimens of late Tremadocian solutans from the Fezouata Shale, morphologically intermediate between Minervaecystis vidali (late Tremadocian, France) and Plasiacystis mobilis, are assigned to Nimchacystis agterbosi gen. et sp. nov. The diagnosis of the syringocrinid family Minervaecystidae is modified to include the four genera Minervaecystis, Nimchacystis, Pahvanticystis, and Plasiacystis, all characterised by an ovoid theca, a laterally inserted feeding appendage, and a twisted, flattened dististele. Minervaecystids are interpreted as active epibenthic detritus feeders, using their dististele to crawl on soft substrates. The newly described solutan taxa highlight that the benthic communities of Fezouata Biota are more diverse than what was previously described.

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Section: Systematic Palaeontologymentioning

confidence: 70%

Solutan echinoderms from the Fezouata Shale Lagerstätte (Lower Ordovician, Morocco): diversity, exceptional preservation, and palaeoecological implications

Dupichaud,

Lefebvre,

Milne

et al. 2023

Front. Ecol. Evol.

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“…eocrinoids, rhombiferans) (see e.g. Parsley 2009Parsley , 2012Zamora et al 2013a, this volume;Nohejlová & Fatka 2016).…”

Section: Systematic Palaeontologymentioning

confidence: 99%

Late Ordovician solutan echinoderms from the Western Tafilalt, Morocco

Nohejlová

Lefèbvre

2021

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In the western Tafilalt area, eastern Anti-Atlas (Morocco), solutan echinoderms are a major faunal element of most echinoderm Lagerstätten occurring within the Lower Ktaoua Formation (late Sandbian-early Katian). For the first time, members of the class Soluta are formally described from Morocco and Africa. All solutans from the Lower Ktaoua Formation are identified as Dendrocystites aff. sedgwicki. Three size-related morphotypes, probably corresponding to successive growth stages (‘juvenile’, ‘adult’ and ‘gerontic’), could be distinguished within the abundant and well-preserved material from Morocco. The occurrence of the genus Dendrocystites in the western Tafilalt confirms the strong faunal affinities between Morocco and other regions of the Mediterranean Province (Czech Republic and Spain) in Late Ordovician times. In high palaeolatitude (peri-)Gondwanan areas, Dendrocystites was a gregarious solutan living in shallow, siliciclastic settings at or above storm-wave base.

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The Cambrian Substrate Revolution and the early evolution of attachment in suspension-feeding echinoderms

Zamora

Deline

Álvaro

et al. 2017

Earth-Science Reviews

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The Cambrian, characterized by the global appearance of diverse biomineralized metazoans in the fossil record for the first time, represents a pivotal point in the history of life. This period also documents a major change in the nature of the sea floor:Neoproterozoic-type substrates stabilized by microbial mats were replaced by unconsolidated soft substrates with a well-developed mixed layer. The effect of this transition on the ecology and evolution of benthic metazoans is termed the Cambrian Substrate Revolution (CSR), and this is thought to have impacted greatly on early suspension-feeding echinoderms in particular. According to this paradigm, most echinoderms rested directly on non-bioturbated soft substrates as sediment attachers and stickers during the Cambrian Epoch 2. As the substrates became increasingly disturbed by burrowing, forming a progressively thickening mixed layer, echinoderms developed new strategies for attaching to firm and hard substrates. To test this model, we evaluated the mode of attachment of 83 Cambrian suspension-feeding echinoderm species; attachment mode was inferred based on direct evidence in fossil specimens and interpretations of functional morphology. These data were analyzed quantitatively to explore trends in attachment throughout the Cambrian. In contrast to previous studies, the majority of Cambrian clades (eocrinoids, helicoplacoids, helicocystoids, isorophid edrioasteroids, and solutes) are now interpreted as hard (shelly) substrate attachers.Only early edrioasteroids attached directly to firm substrates stabilized by microbially induced sedimentary structures. Contrary to the predictions of the CSR paradigm, our study demonstrates that Cambrian echinoderms were morphologically pre-adapted to the substrate changes that occurred during the Cambrian, allowing them to fully exploit the appearance of hardgrounds in the Furongian. We find no support for the claim that

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Ontogeny and morphology of Cambrian eocrinoid Akadocrinus (Barrandian area, Czech Republic)

Cited by 9 publications

References 18 publications

Solutan echinoderms from the Fezouata Shale Lagerstätte (Lower Ordovician, Morocco): diversity, exceptional preservation, and palaeoecological implications

Solutan echinoderms from the Fezouata Shale Lagerstätte (Lower Ordovician, Morocco): diversity, exceptional preservation, and palaeoecological implications

Late Ordovician solutan echinoderms from the Western Tafilalt, Morocco

The Cambrian Substrate Revolution and the early evolution of attachment in suspension-feeding echinoderms

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