Cambrogeorginidae fam. nov., soft-integumented Problematica from the Middle Cambrian of Australia

Müller, Klaus J.; Hinz, Ingelore

doi:10.1080/03115519208619115

Cited by 17 publications

(10 citation statements)

References 11 publications

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“…3, The Rogers Ridge locality (indicated by hollow star) within the Duchess Embayment. Southgate, 1986;Southgate et al, 1988;Muller and Hinz, 1992;Hinz-Schallreuter, 1993;Muller and Hinz-Schallreuter, 1993;Kruse, 1998;Mehl, 1998; personal observations). A particularly diverse and well-preserved assemblage-and the focus of this study-occurs in the Monastery Creek Formation [formerly re ferred to as the Beetle Creek Formation (Russell and Trueman, 1971)] exposed in the Burke River Structural Belt -140 km southeast of Mt.…”

Section: Geologymentioning

confidence: 99%

“…The Monastery Creek Formation is divided into two mem bers: the lower Siltstone Member, a 50-60-m-thick succession containing white fissile siltstone, chert, and minor pelletal phos phorite; and the upper Monastery Creek Phosphorite Member, a 10-15-m-thick unit comprising grainstone phosphorite, chert, phosphatic and siliceous siltstone, shale, sandstone, and phosphatic limestone (de Keyser and Cook, 1972;Soudry and Southgate, 1989). Phosphatized fossils occur throughout the Monastery Creek Phosphorite Member; the fossils discussed in this study come from two beds located at -6 and -7.5 m above the contact with the Siltstone Member, and -8.7 and -7.2 m, respectively, below a marker bed containing hollow chert nodules (noted in Muller and Hinz, 1992). The unit from which the fossils derive consists of tabular, fine-grained limestones -10-15 cm thick, de void of hummocky cross-stratification or other cross-lamination, suggesting deposition below fair-weather wave base.…”

Section: Geologymentioning

confidence: 99%

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Halkieriids in Middle Cambrian Phosphatic Limestones From Australia

Porter

2004

Journal of Paleontology

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Halkieriids are part of a distinctive Early Cambrian fauna, the ''Tommotian fauna'' sensu Sepkoski (1992), that is preserved mostly as phosphatic and secondarily phosphatized skeletal elements. The distinctiveness of the Tommotian fauna is ascribed, in part, to its preferential elimination during the end-Early Cambrian mass extinction event (the ''Botomian extinction''). Newly discovered halkieriids in phosphatic limestones of the Middle Cambrian (Ptychagnostus gibbus Zone) Monastery Creek Formation, Georgina Basin, Australia, now indicate that this group not only survived the end-Early Cambrian extinction, but was at least locally abundant thereafter. Most of the Georgina halkieriid sclerites can be accommodated within a single species, Australohalkieria superstes new genus and species, described and partly reconstructed here. Remaining sclerites probably represent two additional but rare halkieriid species. Additional newly discovered sclerites may have affinities with the sachitids, another problematic ''Tommotian'' taxon related to the halkieriids. Rare wiwaxiid sclerites extend the taphonomic and geographic distribution of this clade. The Monastery Creek Formation provides a valuable window on Middle Cambrian life, both because it provides information that is distinct from but complementary to other, similarly aged windows (e.g., the Burgess Shale) and because it represents a taphonomic window similar to those that preserve Early Cambrian small shelly problematica. A decline during the Cambrian in conditions necessary for the early diagenetic phosphatization of shallow-shelf and platform limestones may have effectively closed this taphonomic window, potentially biasing apparent patterns of diversity change through the period.

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Section: Geologymentioning

confidence: 99%

Section: Geologymentioning

confidence: 99%

Halkieriids in Middle Cambrian Phosphatic Limestones From Australia

Porter

2004

Journal of Paleontology

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“…Cellular permineralization in phosphate (Yuan et al 2005), gold van Warmelo 1974, Hallbauer et al 1977), calcite (Pflug 1994), or silica Krinsley 1992, 1998) has yielded the most convincing fossil record of Precambrian terrestrial lichens and microbes, but permineralization is rare in well-drained paleosols (Rye and Holland 2000). In Phanerozoic rocks, permineralized trees (Retallack 1981) and microbes (Klappa 1978(Klappa , 1979Trewin and Knoll 1999) are known from well-drained paleosols, but permineralization is more common in intertidal or wetland paleosols, such as Cambrian (510 Ma) phosphorites of Queensland (Fleming and Rigby 1972, Southgate 1986, Müller and Hinz 1992, the Devonian (410 Ma) Rhynie Chert of Scotland (Taylor et al 2004), and (310 Ma) Pennsylvanian, calcite coal-balls of Illinois (Stubblefield and Taylor 1988). Most known Precambrian permineralized microbiotas are associated with marine or lacustrine stromatolites (Knoll et al 1993, Schopf et al 2007, banded iron formations (Maliva et al 2005), or pillow basalts (Schopf and Packer 1987).…”

Section: Microbial Preservational Stylesmentioning

confidence: 99%

Criteria For Distinguishing Microbial Mats and Earths

Retallack¹

2012

Microbial Mats in Silicilastic Depositional Systems Through Time

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Microbial earths are communities of microscopic organisms living in well-drained soil. Unlike aquatic microbial mats and stromatolites, microbial earths are sheltered from ultraviolet radiation, desiccation, and other surficial hazards within soil cracks and grain interstices. Currently, such ecosystems are best known in small areas of unusually cold, hot, or saline soils unfavorable to multicellular plants and animals. During the Precambrian, microbial earths may have been more widespread, but few examples have been reported. This review outlines a variety of features of modern microbial earths that can be used to distinguish them from aquatic microbial mats and stromatolites in the fossil record. Microbial earths have vertically oriented organisms intimately admixed with minerals of the soil, whereas microbial mats are laminated and detachable from their mineral substrate as flakes, skeins, and rollups. Microbial earths have irregular relief, healed desiccation cracks, and pressure ridges, whereas microbial mats have flexuous, striated domes, and tufts. Microbial earths form deep soil profiles with downward variations in oxidation, clay abundance, and replacive nodular subsurface horizons, whereas microbial mats form as caps to unweathered, chemically reduced sedimentary layers. Microbial earths develop increasingly differentiated soil profiles through time, whereas microbial mats build upward in laminar to domed increments. Microbial earths are found in nonmarine sedimentary facies, whereas microbial mats form in lacustrine, floodplain, and marine sedimentary facies. Microbial mats and stromatolites are known back to the oldest suitably preserved sedimentary rocks in the 3458 Ma Apex Chert and 3430 Ma Strelley Pool Formation (respectively) of the Pilbara region of Western Australia. The geological antiquity of microbial earths extends back to 2760 Ma in the Mount Roe paleosol of the Hamersley Group near Whim Creek, Western Australia.

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“…At present, the distinctiveness of the unique plate morphology precludes a position within the Palaeoscolecidae or other existing families. The closest superficial resemblance appears to be with the problematic Cambrogeorginidae (Müller and Hinz 1992), although in that case there are many radiating ridges, and it is unclear whether the group is closely related to palaeoscolecidans at all.…”

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confidence: 99%

Diverse middle Ordovician palaeoscolecidan worms from the Builth‐Llandrindod Inlier of central Wales

Botting

Muir

Roy³

et al. 2012

Palaeontology

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Palaeoscolecidan worms are rare, Early Palaeozoic fossils with uncertain affinities within the Ecdysozoa. They are locally abundant in the Cambrian and scattered in the Early Ordovician, but very sparse thereafter. Forty-four specimens have been collected from the Middle Ordovician of the BuilthLlandrindod Inlier of Mid Wales and include well-preserved material assigned to seven new genera, with four additional species in open nomenclature. An additional specimen from the Arenig Pontyfenni Formation of South Wales is also described in open nomenclature. The total demonstrates much greater palaeoscolecid diversity than hitherto suspected for this time. The specimens are preserved as cuticle fragments in shales and siltstones, often of submillimetre size but in many cases with excellent preservation. The level of detail preserved in some is equal to that found in Cambrian phosphatized faunas. The new approach to collecting, and the recognition that this material can yield taxonomically useful information, opens new avenues for palaeoscolecidan research in siliciclastic environments. The new taxa are the following: Radnorscolex bwlchi gen. et sp. nov., Aggerscolex murchisoni gen. et sp. nov., Bullascolex inserere gen. et sp. nov., Wernia eximia gen. et sp. nov., Ulexiscolex ormrodi gen. et sp. nov., Pluoscolex linearis gen. et sp. nov. and Loriciscolex cuspidus gen. et sp. nov. The high diversity, and the taxonomic separation from known groups described primarily from Cambrian carbonates, implies that palaeoscolecidans either diversified significantly during the Ordovician or were taxonomically segregated between carbonate and siliciclastic settings. Palaeobiological findings also include confirmation that some palaeoscolecid basal cuticles were solid and others reticulate, plates (and platelets) could form by lateral accretion, plates were in part primarily phosphatic and in part organic and that in at least some groups, platelet secretion occurred external to plate secretion.

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Cambrogeorginidae fam. nov., soft-integumented Problematica from the Middle Cambrian of Australia

Cited by 17 publications

References 11 publications

Halkieriids in Middle Cambrian Phosphatic Limestones From Australia

Halkieriids in Middle Cambrian Phosphatic Limestones From Australia

Criteria For Distinguishing Microbial Mats and Earths

Diverse middle Ordovician palaeoscolecidan worms from the Builth‐Llandrindod Inlier of central Wales

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