Synchrotron imagery of phosphatized eggs in Waptia cf. W. fieldensis from the middle Cambrian (Miaolingian, Wuliuan) Spence Shale of Utah

Abstract Exceptionally preserved fossil eggs and embryos provide critical information regarding paleoembryogenesis, reproductive strategies, and the early ontogeny of early arthropods, but the rarity of preservation of both eggs and egg-bearing organisms in situ limits their use in detailed evolutionary developmental (evo-devo) studies. Burgess Shale-type deposits preserve rare instances of egg-bearing arthropods as carbonaceous compressions; however, the eggs are usually poorly preserved with no compelling evidence of embryos. We describe the first record of a brooding specimen of Waptia cf. W. fieldensis from the Spence Shale, a Cambrian (Wuliuan Stage) Burgess Shale-type deposit in northeastern Utah and southeastern Idaho. This is the first record of an egg-bearing arthropod from the Spence Shale and it exhibits two distinct modes of preservation among eggs within the single clutch: carbonization and phosphatization. Unlike the egg-bearing Burgess Shale specimens, many eggs of this Utah specimen are also preserved three-dimensionally. In addition, synchrotron radiation X-ray tomographic microscopy reveals internal distributions of mineral phases, along with potential remnants of the egg membrane and attachment structures, but, as in the Burgess Shale, no explicit traces of developing embryos. The distinct modes of preservation highlight the existence of diagenetic microenvironments within some eggs, but not in others during fossilization.

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Symbiosis in the Cambrian: enteropneust tubes from the Burgess Shale co-inhabited by commensal polychaetes

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2021.0061 ◽

2021 ◽

Vol 288 (1951) ◽

pp. 20210061

Author(s):

Karma Nanglu ◽

Jean-Bernard Caron

Keyword(s):

Fossil Record ◽

First Record ◽

Animal Behaviour ◽

Burgess Shale ◽

Middle Cambrian ◽

Reproductive Structures ◽

Ecological Relationship

The in situ preservation of animal behaviour in the fossil record is exceedingly rare, but can lead to unique macroecological and macroevolutionary insights, especially regarding early representatives of major animal clades. We describe a new complex ecological relationship from the middle Cambrian Burgess Shale (Raymond Quarry, Canada). More than 30 organic tubes were recorded with multiple enteropneust and polychaete worms preserved within them. Based on the tubicolous nature of fossil enteropneusts, we suggest that they were the tube builders while the co-preserved polychaetes were commensals. These findings mark, to our knowledge, the first record of commensalism within Annelida and Hemichordata in the entire fossil record. The finding of multiple enteropneusts sharing common tubes suggests that either the tubes represent reproductive structures built by larger adults, and the enteropneusts commonly preserved within are juveniles, or these enteropneusts were living as a pseudo-colony without obligate attachment to each other, and the tube was built collaboratively. While neither hypothesis can be ruled out, gregarious behaviour was clearly an early trait of both hemichordates and annelids. Further, commensal symbioses in the Cambrian may be more common than currently recognized.

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Presence of Naraoia Walcott, 1912 (Nektaspida, Arthropoda) in the middle Cambrian of Europe (Murero, NE Spain)

Spanish Journal of Palaeontology ◽

10.7203/sjp.33.1.13243 ◽

2018 ◽

Vol 33 (1) ◽

pp. 83

Author(s):

Rodolfo Gozalo ◽

Mª Eugenia Dies-Álvarez ◽

José Antonio Gámez VIintaned ◽

Juan B. Chirivella ◽

Eladio Liñan

Keyword(s):

British Columbia ◽

First Record ◽

Early Cambrian ◽

Burgess Shale ◽

Evolutionary Potential ◽

Middle Cambrian ◽

The Family ◽

Ne Spain

The genus Naraoia Walcott, 1912, a Burgess Shale-type fossil known from the lower and middle Cambrian of British Columbia (Canada), Idaho and Utah (USA), as well as from Yunnan and Guizhou provinces (China), is now reported from the middle Cambrian of Murero (Zaragoza, Spain), which is the first record in the Acadobaltic province. The only fragmented specimen found is determined as Naraoia sp., its age being Pardailhania multispinosa Zone (Drumian Stage). This new datum reinforces the hypothesis of the existence of a cosmopolitan faunal substrate in early Cambrian times, which is to some extent refl ected in the mid Cambrian by faunal groups of low evolutionary potential as the family Naraoiidae and other soft-bodied fossil taxa.

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In situ benthos and paleo-oxygenation in the Middle Cambrian Burgess Shale, British Columbia, Canada

Geology ◽

10.1130/0091-7613(1995)023<1079:isbapo>2.3.co;2 ◽

1995 ◽

Vol 23 (12) ◽

pp. 1079 ◽

Cited By ~ 51

Author(s):

Peter A. Allison ◽

Carlton E. Brett

Keyword(s):

British Columbia ◽

Burgess Shale ◽

Middle Cambrian

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First record of the brachiopodLingulella waptaensiswith pedicle from the Middle Cambrian Burgess Shale

Acta Zoologica ◽

10.1111/j.1463-6395.2009.00394.x ◽

2010 ◽

Vol 91 (2) ◽

pp. 150-162 ◽

Cited By ~ 12

Author(s):

Sandra Pettersson Stolk ◽

Lars Erik Holmer ◽

Jean-Bernard Caron

Keyword(s):

First Record ◽

Burgess Shale ◽

Middle Cambrian

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The persistence of Burgess Shale-type faunas: implications for the evolution of deeper-water faunas

Earth and Environmental Science Transactions of the Royal Society of Edinburgh ◽

10.1017/s0263593300028716 ◽

1989 ◽

Vol 80 (3-4) ◽

pp. 271-283 ◽

Cited By ~ 74

Author(s):

S. Conway Morris

Keyword(s):

Lower Cambrian ◽

Burgess Shale ◽

Middle Cambrian

ABSTRACTDiscoveries, most of them recently, in more than thirty Lower and Middle Cambrian horizons with soft-bodied fossils have shown that forty-one of the genera occur also in the celebrated Burgess Shale (Middle Cambrian). Significantly, they tend to have lengthy stratigraphic durations which together encompass an interval from the early Lower Cambrian (Tommotian) to near the end of the Middle Cambrian. At least some genera have also wide geographical ranges, with occurrences around much of the Laurentian (N America) craton, and also in N and S China, Australia, Siberia, Spain and Poland. Although a few genera, e.g. Isoxys, may have been pelagic, for the most part these distributions are explained in terms of a deeper-water biota with an evolutionarily conservative aspect. Both the origins and further recruitment to this biota may have been from shallower water, with more limited in situ diversification. It is speculated that this distinctive Cambrian biota was gradually driven to extinction with the arrival of Ordovician competitors, although some relics may have survived until at least the Devonian. This history has implications for our understanding of deeper-water faunas throughout the Phanerozoic, and supports the notion that archaic forms may take refuge in this environment.

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First record of Ubaghsicystis (Eocrinoidea - Echinodermata) from the Cambrian (Miaolingian, Wuliuan) of Sonora, Mexico: Biostratigraphical and paleoecological considerations

Revista de Biología Tropical ◽

10.15517/rbt.v69isuppl.1.46326 ◽

2021 ◽

Vol 69 (Suppl.1) ◽

pp. 51-65

Author(s):

Blanca-Estela Buitrón-Sánchez ◽

Francisco-Javier Cuen-Romero ◽

Matilde-Sylvia Beresi ◽

Rogelio Monreal

Keyword(s):

Marine Environment ◽

Research Work ◽

First Record ◽

Sedimentary Sequence ◽

Burgess Shale ◽

Middle Cambrian ◽

Stratigraphic Section ◽

Invertebrate Fossils ◽

First Time ◽

Open Shelf

Introduction: The present work constitutes the first record of Ubaghsicystis Gil-Cid & Domínguez-Alonso (Echinodermata-Eocrinoidea) in the El Gavilán Formation, exposed in the El Sahuaral Hill, a new Cambrian locality of central Sonora, Mexico. The El Gavilán Formation is a sedimentary sequence mainly made up of shale interbedded with limestone, with abundant invertebrate fossils, deposited in an open shelf marine environment. Objective: The main objective of this research work is to describe the species Ubaghsicystis cf. U. segurae for the first time in Mexico, in addition to biostratigraphic and paleoecological considerations. Methods: A composite stratigraphic section of the El Gavilán Fm. was measured in central Sonora, where samples corresponding to eocrinods were collected, the material was examined in the Microscope Leica MZ10. Results: The biotic association is composed of reticulosan sponges, chancelloriids (Chancelloria eros, Allonnia tintinopsis, Archiasterella sp.), hyolithids, brachiopods, trilobites (Quadragnostus depressa, Peronopsis sp., Tonkinella valida, and Elrathina sp.), and echinoderms (Ubaghsicystis cf. U. segurae). Regarding the age, the trilobite association establishes a chronostratigraphic position from the middle Cambrian (Miaolingian, Wuliuan), Altiocculus Subzone, Ehmaniella Zone. The material studied is constituted by isolated echinoderm plates, which probably represent various cycles of theca plates assigned to Ubaghsicystis cf. U. segurae. The genus Ubaghsicystis has been scarcely recorded in a few Cambrian regions (e.g., Burgess Shale in Canada and Los Barrios de Luna in Spain), so that the information about this taxon is limited. Conclusions: The Cambrian succession of Sonora, where Ubaghsicystis occurred, was part of the border from the Laurentia craton during this period, located near the Paleoequator during this period, where ideal conditions for increasing diversity and abundance of species were developed, including echinoderms.

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Banffia constricta, a putative vetulicolid from the Middle Cambrian Burgess Shale

Transactions of the Royal Society of Edinburgh Earth Sciences ◽

10.1017/s0263593305000052 ◽

2005 ◽

Vol 96 (02) ◽

pp. 95 ◽

Cited By ~ 1

Keyword(s):

Burgess Shale ◽

Middle Cambrian

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The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100071107 ◽

1973 ◽

Vol 31 ◽

pp. 132-133 ◽

Cited By ~ 1

Author(s):

R. E. Herfert

Keyword(s):

Surface Characterization ◽

Analytical Techniques ◽

X Ray Diffraction ◽

Depth Of Penetration ◽

X Ray ◽

The Past ◽

Transmission Electron ◽

Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

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