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1

Small shelly fossils from the argillaceous facies of the Lower Cambrian Forteau Formation of Western Newfoundland

100%

Skovsted C. B. , Peel J. S.

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nr 4

EN

A diverse fauna of helcionelloid molluscs, hyoliths, and other small shelly fossils is described from limestone layers within the Forteau Formation of the Bonne Bay region in western Newfoundland. The fauna is dominated by internal moulds of various molluscs and tubular problematica, but also includes hyolith opercula, echinoderm ossicles, and other calcareous small shelly fossils preserved by phosphatisation. Originally organophosphatic shells are comparatively rare, but are represented by brachiopods, hyolithelminths, and tommotiids. The fauna is similar to other late Early Cambrian faunas from slope and outer shelf settings along the eastern margin of Laurentia and may be of middle Dyeran age. The similarity of these faunas indicates that at least by the late Early Cambrian, a distinctive and laterally continuous outer shelf fauna had evolved. The Forteau Formation also shares elements with faunas from other Early Cambrian provinces, strengthening ties between Laurentia and Australia, China, and Europe during the late Early Cambrian. Two new taxa of problematic fossil organisms are described, the conical Clavitella curvata gen. et sp. nov. and the wedge−shaped Sphenopteron boomerang gen. et sp. nov.

2

Hyoliths and small shelly fossils from the Lower Cambrian of North-East Greenland

100%

Malinky J. M. , Skovsted C. B.

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nr 4

EN

The hyolith assemblage from the Lower Cambrian Bastion Formation of North−East Greenland is significant in that it contains several hyolith taxa that possess traits of both orders Hyolithida and Orthothecida. They possess morphological traits that seem to be characteristic of the ancestral forms of both groups. In addition, many hyolith taxa from this interval are globally distributed, supporting the notion that these fossils have potential as stratigraphic indicators. This assemblage contains genera and/or species seen in Australia, North America, the Siberian Platform, and South China. Hyoliths identified include the hyolithids Parkula bounites, Hyptiotheca karraculum, Microcornus eximius, M. petilus, Paracornus poulseni gen. et sp. nov., as well as Similotheca similis?, S. bastionensis sp. nov., and S. groenlandica sp. nov.; two opercula remain in open nomenclature. Orthothecids from this assemblage are one unnamed species each of Contitheca and Gracilitheca. Large, macro−sized hyoliths from the same formation described by Poulsen (1932) are mostly unidentifiable, although an operculum formerly identified as Hyolithes (Orthotheca) communis is reassigned to Hyptiotheca. Problematic organisms of uncertain affinity include Cupitheca holocyclata, Conotheca australiensis, an unnamed species of Coleolus, and the cap−shaped Cassitella baculata gen. et sp. nov. that may be an operculum of some as yet unknown organism. Missarzhevsky (1969) used Hyolithes(Orthotheca) bayonet var. groelandicus and H. (O.) bayonet var. longus as the basis for Lenatheca, but the specimens on which that genus is based are too poorly known for a proper diagnosis of Lenatheca.

3

The tommotiid Camenella reticulosa from the Early Cambrian of South Australia: morphology, scleritome reconstruction, and phylogeny

80%

Skovsted C. B. , Balthasar U. , Brock G. A. , Paterson J. R.

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nr 3

525-540

EN

The tommotiid Camenella reticulosa is redescribed based on new collections of well preserved sclerites from the Arrowie Basin (Flinders Ranges), South Australia, revealing new information concerning morphology and microstructure. The acutely pyramidal mitral sclerite is described for the first time and the sellate sclerite is shown to be coiled through up to 1.5 whorls. Based on Camenella, a model is proposed by which tommotiid sclerites are composed of alternating dense phosphatic, and presumably originally organic−rich, laminae. Camenella is morphologically most similar to Lapworthella, Kennardia, and Dailyatia, and these taxa are interpreted to represent a monophyletic clade, here termed the “camenellans”, within the Tommotiida. Potential reconstructions of the scleritome of Camenella are discussed and although a tubular scleritome construction was recently demonstrated for the tommotiids Eccentrotheca and Paterimitra, a bilaterally symmetrical scleritome model with the sclerites arranged symmetrically on the dorsal surface of a vagrant animal can not be ruled out.

4

The problematic early Cambrian fossil Tumulduria incomperta represents the detached ventral interarea of a paterinid brachiopod

80%

Skovsted C. B. , Kouchinsky A. , Bengtson S. , Holmer L. E.

Acta Palaeontologica Polonica

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2014

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tom 59

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nr 2

EN

The organophosphatic early Cambrian (Terreneuvian, Cambrian Stage 2) fossil Tumulduria incomperta has been problematic ever since its original description in 1969. Comparison of abundant specimens from the Lower Cambrian of Siberia with co-occurring brachiopod valves show that T. incomperta represents the central portion of the ventral interarea of a paterinid brachiopod similar to Cryptotreta neguertchenensis, and that the domed central portion of typical Tumulduria specimens represents the ridge-like pseudodeltidium of the interarea.

5

Shelly fossils from the lower Cambrian White Point Conglomerate, Kangaroo Island, South Australia

61%

Betts M. J. , Claybourn T. M. , Brock G. A. , Jago J. B. , Skovsted C. B. , Paterson J. R.

Acta Palaeontologica Polonica

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2019

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tom 64

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nr 3

EN

The lower Cambrian (Series 2) White Point Conglomerate (WPC) on Kangaroo Island, South Australia contains exotic clasts representing a diverse array of lithologies, including metamorphics, chert, sandstone, and abundant carbonates, notably archaeocyath-rich bioclastic limestone. Acetic acid digestion of the WPC bioclastic limestone clasts reveals a diverse shelly fauna. This assemblage includes abundant organophosphatic brachiopods such as Cordatia erinae Brock and Claybourn gen. et sp. nov., Curdus pararaensis, Eodicellomus elkaniformiis, Eohadrotreta sp. cf. E. zhenbaensis, Eoobolus sp., Kyrshabaktella davidii, and Schizopholis yorkensis. Additional shelly taxa include the solenopleurid trilobite Trachoparia? sp., the tommotiids Dailyatia odyssei, Dailyatia decobruta Betts sp. nov., Kelanella sp., and Lapworthella fasciculata, spines of the bradoriid arthropod Mongolitubulus squamifer, and several problematica, such as Stoibostrombus crenulatus and a variety of tubular forms. The upper age limit for the WPC is constrained by biostratigraphic data from the overlying Marsden Sandstone and Emu Bay Shale, which are no younger than the Pararaia janeae Trilobite Zone (Cambrian Series 2, Stage 4). The shelly fossil assemblage from the WPC limestone clasts indicates an upper Dailyatia odyssei Zone (= Pararaia tatei to lower P. janeae trilobite zones), equivalent to the Atdabanian–early Botoman of the Siberian scheme. This contrasts with the previously suggested late Botoman age for the limestone clasts, based on the diverse archaeocyath assemblage. The minor age difference between the WPC and its fossiliferous limestone clasts suggests relatively rapid reworking of biohermal buildups during tectonically-active phases of deposition in the Stansbury Basin.

6

Early–middle Cambrian stratigraphy and faunas from northern Siberia

41%

Kouchinsky A. , Alexander R. , Bengtson S. , Bowyer F. , Clausen S. , Holmer L. E. , Kolesnikov K. A. , Korovnikov I. V. , Pavlov V. , Skovsted C. B. , Ushatinskaya G. , Wood R. , Zhuravlev A. Y.

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tom 67

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nr 2