Two new orthothecids from the Cambrian of the Barrandian area (Hyolitha, Skryje-Týřovice Basin, Czech Republic)

Valent, Martín; Fatka, Oldřich; Szabad, Michal; Micka, V.; Ladislav, Marek

doi:10.3140/bull.geosci.1142

Cited by 9 publications

(7 citation statements)

References 10 publications

(13 reference statements)

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“…Valent et al . () suggested that this specimen from Sirius Passet may belong to Circotheca Syssoiev, , as emended by Berg‐Madsen & Malinky (), but the operculum of the latter is circular.…”

Section: Hyolithellus Sp Figure T Y–aamentioning

confidence: 66%

“…Circotheca sp. differs from the type species, and from Circotheca smetanai Valent et al ., from the middle Cambrian Buchova Formation of the Czech Republic, in the much greater length of its cardinal processes.…”

Section: Hyolithellus Sp Figure T Y–aamentioning

confidence: 98%

“…A similar disposition of opercular folds is seen in Probactrotheca briketa Valent et al ., from the Skryje Member of the Buchava Formation (Cambrian Series 3) of the Czech Republic, but this has a pronounced trapezoidal shape with steeply sloping lateral surfaces and a median fold bisecting the short cardinal shield. The operculum of Novitatus lermontovae Syssoiev, from the Botoman Stage (Cambrian Series 2) of the Siberian platform has a broad ventral fold and concave margin (Meshkova et al .…”

Section: Hyolithellus Sp Figure T Y–aamentioning

confidence: 99%

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The Buen Formation (Cambrian Series 2) biota of North Greenland

Peel

Willman

2018

Papers in Palaeontology

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The diverse metazoan fauna from the upper member of the Buen Formation of North Greenland is described as a complement to published descriptions of the exceptionally preserved fauna of the Sirius Passet Lagerstätte which occurs in the lowest beds of the formation. Considered together with organic‐walled microfossils, which are absent from the Sirius Passet Lagerstätte on account of regional metamorphism, the fauna from the upper member provides an extended picture of the Buen Formation biota (Cambrian, Series 2, Stages 3–4; Montezuman–Dyeran of Laurentian usage). Although dominated numerically by specimens of the olenelline trilobites Limniphacos and Mesolenellus, the oldest assemblages (Montezuma–Dyeran boundary) from the upper member of the Buen Formation are characterized by a high diversity of hyoliths which often occur as partial associations of conch, operculum and helens in the dark mudstones; hyoliths are rare in the Sirius Passet Lagerstätte. Sponges are rare in the upper Buen Formation but diverse at Sirius Passet. Unlike the Sirius Passet Lagerstätte, fossil remains of non‐mineralized metazoans with limbs and other details of internal anatomy do not occur in the upper Buen Formation, although organic tubes assigned to a new selkirkiid stem group priapulid (Sullulika) are common. New taxa: Alutella siku sp. nov., Sullulika broenlundi gen. et sp. nov., Nevadotheca boerglumensis sp. nov., Kalaallitia myliuserichseni gen. et sp. nov., Nasaaraqia hyptiotheciformis gen. et sp. nov., Trapezovitus malinkyi sp. nov., Decoritheca? hageni sp. nov.

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Section: Hyolithellus Sp Figure T Y–aamentioning

confidence: 66%

Section: Hyolithellus Sp Figure T Y–aamentioning

confidence: 98%

Section: Hyolithellus Sp Figure T Y–aamentioning

confidence: 99%

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The Buen Formation (Cambrian Series 2) biota of North Greenland

Peel

Willman

2018

Papers in Palaeontology

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“…The name Circotheca has been widely used for tubular fossils from this level, particularly in the Tommotian of Siberia and Meischucunian of China (Qian the operculum of representatives of the genus Circotheca shows distinct paired bilobate cardinal processes (see type species Circotheca styla (Holm, 1893) in Berg-Madsen & Malinky 1999 (text-Fig. 9E, F and R) or Circotheca smetanai Valent et al 2012 ( Fig. 2A, B)) which are not present in any form at Holm's specimen.…”

Section: Operculamentioning

confidence: 99%

An orthothecid hyolith with a digestive tract from the early Cambrian of Bornholm, Denmark

Berg‐Madsen

Valent

Ebbestad

2018

GFF

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The hyolith assemblage from the early Cambrian of Bornholm, Denmark, shows a higher diversity than contemporary assemblages in Baltoscandia. The most common species in the Green Shales (Laeså Formation, Norretorp Member, Cambrian Stage 3), is Hyolithes [=Hyolithus] (Orthotheca) johnstrupi Holm, 1893. A specimen of this species shows a well-preserved and almost complete digestive tract, folded into an approximately 22 mm long chevron-like structure comprised of at least 20 arcuate loops on the ventral side and a flattened, gently sinuous to straight anal tube on the dorsal side. The thin, phosphatic outer shell layer of the conch is crushed under the digestive tract due to compaction while the digestive tract is preserved in three dimensions and appears undisturbed. The shape of the digestive tract is similar to that of the middle Cambrian Guduguwan hardmani (Etheridge) from Australia and the lower Cambrian specimens from Russia described by Meškova & Sysoev. The Danish specimen is probably an adult, lending support to the idea that the orthothecid digestive tract becomes more complex during ontogeny. Hyolithus (Orthotheca) johnstrupi is revised and here referred to Circotheca Sysoev, 1958.

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“…oboediens Marek, 1981Slapylites Marek, 1980-S. signatulus (Novák, 1891 Skryjelites Marek in Valent et al, 2011a-S. auritus Marek in Valent et al, 2011aQuasimolites Valent et al, 2011a-Q. quasimodo Valent et al, 2011a Order Orthothecida Marek, 1966Probactrotheca Marek in Valent et al, 2011b Marek in Valent et al, 2011b;Circotheca Sysoev, 1958emended Berg-Madsen and Malinky, 1999-C. smetanai Marek in Valent et al 2011b.…”

Section: Introductionmentioning

confidence: 96%