A new study of Marrella splendens (Arthropoda, Marrellomorpha) from the Middle Cambrian Burgess Shale, British Columbia, Canada

2006 ◽  
Vol 43 (6) ◽  
pp. 721-742 ◽  
Author(s):  
Diego C García-Bellido ◽  
Desmond H Collins
Keyword(s):  
Alimentary Canal ◽  
Three Dimensional ◽  
Circulatory System ◽  
Burgess Shale ◽  
Middle Cambrian ◽  
Body Segments ◽  
Royal Ontario Museum ◽  
New Information ◽  
Shale Formation ◽  
Pair Of Antennae

Study of over 1000 specimens of Marrella splendens Walcott, 1912, out of the more than 9000 collected by the Royal Ontario Museum (ROM) since 1975, has produced new information on the anatomy, functional morphology, and behaviour of this most common arthropod in the Burgess Shale fauna. Among the new features recognized is the distinction between the alimentary canal and circulatory system; where the former is generally three-dimensional and slightly reflective, the latter never presents any relief and is very reflective. A larger range of size is now known, from 2.4 to 24.5 mm in length, with small individuals possessing 17 body segments to large specimens with more than 26 body segments, representing an almost complete ontogenetic series. The second pair of "antennae" is now interpreted as swimming appendages, since the five distal segments are dorsoventrally compressed, fringed with setae and with a considerable blood supply, providing a paddlelike appendage capable of producing a considerable propelling force. The ROM collections extend the geographical distribution of Marrella 13 km to the southeast and the stratigraphical range through the lowest five members of the Burgess Shale Formation.

The Middle Cambrian Burgess Shale and its relationship to the Stephen Formation in the southern Canadian Rocky Mountains

1998 ◽  
Vol 35 (4) ◽  
pp. 413-436 ◽  
Author(s):  
Terence P Fletcher ◽  
Desmond H Collins
Keyword(s):  
Rocky Mountains ◽  
Main Part ◽  
Canadian Rocky Mountains ◽  
Burgess Shale ◽  
Middle Cambrian ◽  
Royal Ontario Museum ◽  
Shale Formation ◽  
Geologic Setting ◽  
Continuous Deposition ◽  
Zonal Boundary

The Burgess Shale has been an anomalous geologic unit ever since Walcott named it in 1911 as the geographic equivalent of the Ogygopsis Shale in the Middle Cambrian Stephen Formation of southeastern British Columbia, but it has never been recognized outside of its type locality, so its status relative to the Stephen Formation remained uncertain. The geologic setting of the Burgess Shale was determined by Aitken and Fritz in 1968, when they recognized the Cathedral Escarpment and divided the Stephen Formation into a "thin" platformal succession on top of the Escarpment, and a "thick" basinal succession, which included Walcott's Burgess Shale, in front. Fieldwork by Royal Ontario Museum parties between 1982 and 1997 has now demonstrated that the thin and thick Stephen successions lie within different facies belts and should be regarded as separate formations; the Stephen Shale Formation is part of the Middle Carbonate Belt succession, whereas the name Burgess Shale Formation is applied to the thick basinal succession within the Outer Detrital Belt Chancellor Group. Ten distinct members are recognized in the Burgess Shale: Kicking Horse Shale, Yoho River Limestone, Campsite Cliff Shale, Wash Limestone, Walcott Quarry Shale, Raymond Quarry Shale, Emerald Lake Oncolite, Odaray Shale, Paradox Limestone, and Marpole Limestone. In contrast to the Stephen Shale Formation with its nonsequences, the thicker Burgess Shale Formation seems to represent continuous deposition spanning the Glossopleura to Bathyuriscus-Elrathina zonal boundary, incorporating the Polypleuraspis insignis and Pagetia bootes subzones and the main part of the Pagetia walcotti subzone.

The arthropod Sidneyia inexpectans , Middle Cambrian, Burgess Shale, British Columbia

1981 ◽  
Vol 295 (1079) ◽  
pp. 619-653 ◽  
Keyword(s):  
British Columbia ◽  
Posterior Margin ◽  
Three Dimensional ◽  
The Body ◽  
Gut Contents ◽  
Burgess Shale ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Middle Cambrian ◽  
Abdominal Somite

Old and new specimens of Sidneyia inexpectans have been studied and are accompanied by explanatory drawings and photographs. New reconstructions of the animal are given together with a three-dimensional model. The body consisted of a cephalon with a long backwardly directed doublure, a thorax of nine articulating somites, abdomen with cylindrical exoskeleton of two or three somites and a telson. A caudal fan was formed by a pair of uropods articulating at the posterior margin of the last abdominal somite. The cephalon had stalked eyes and preoral antennae but no walking or grasping appendages. The first four somites of the thorax had paired uniramous, prehensile walking legs attached to the body by broad coxae with spiny gnathobases. The coxae were smaller on the five posterior thoracic somites and the paired appendages were biramous, each bearing a gill supported on a flap attached at its proximal end to the first podomere of the leg. The coxa-body attachment resembles that of modern merostomes and is in advance of trilobites. Evidence suggests that Sidneyia was a bottom-living, carnivorous animal eating larger and harder food than trilobites. Gut contents include ostracodes, hyolithids, small trilobites and phosphatic debris. Sidneyia is the earliest known form which could be an ancestor to merostomes, but its body plan and absence of chelicera distinguishes Sidneyia from this group. The holotype of Amiella ornata Walcott, 1911 is reinterpreted and its synonomy with S. inexpectans is confirmed.

A redescription of a rare chordate, Metaspriggina Walcotti Simonetta and Insom, from the Burgess Shale (Middle Cambrian), British Columbia, Canada

2008 ◽  
Vol 82 (2) ◽  
pp. 424-430 ◽  
Author(s):  
Simon Conway Morris
Keyword(s):  
Fossil Record ◽  
Early History ◽  
Fish Scales ◽  
Burgess Shale ◽  
Middle Cambrian ◽  
New Information ◽  
History Of ◽  
The One ◽  
Modes Of Life ◽  
Chengjiang Lagerstätte

Until Recently, our understanding of the earliest history of the fish has been fragmentary in terms of the fossil record and conjectural with respect to many details of phylogeny. Fortunately, significant new information has become available in recent years, most notably from the discoveries of at least three taxa of agnathan fish from the Lower Cambrian Chengjiang Lagerstätte of Yunnan, China (Shu et al., 1999, 2003; Shu, 2003; see also Hou et al., 2002; Hou et al., 2004, p. 192-193; Zhang and Hou, 2004). Two of the taxa (Haikouichthys and Zhangjianichthys) are represented by numerous specimens, but it is noteworthy that amongst the forty-odd Burgess Shale-type occurrences apart from the Chengjiang Lagerstätte, chordates (or indeed cephalochordates and urochordates) are otherwise unknown. The one exception is the Burgess Shale itself, characterized by the rather enigmatic Pikaia gracilens (Conway Morris, 1982, 1998) and the much rarer chordate described herein. Apart from this exceptionally preserved material, the fossil record effectively only begins in the Ordovician (e.g., Sansom et al., 2001, 2005; Sansom and Smith, 2005), in as much putative fish scales from the latest Cambrian (Young et al., 1996) may be better interpreted as arthropodan (see Smith et al., 2001, p. 78). The difficulties of interpreting what is overall an extremely patchy record are further compounded by the fact that the relevance to this early history of the extant agnathan hagfish and lamprey has remained (and indeed to some extent remains) problematic, given the uncertainty as to which of the presumed archaic features have been overprinted by specializations for modes of life that might have had little counterpart in the ancestral forms.

Exceptionally preserved hyolithids from the middle Cambrian of North China

2021 ◽  
pp. 1-9
Author(s):  
Haijing Sun ◽  
Zhixin Sun ◽  
Fangchen Zhao
Keyword(s):  
Species Interactions ◽  
Digestive System ◽  
North China ◽  
Three Dimensional ◽  
Tissue Preservation ◽  
Middle Cambrian ◽  
Morphological Variations ◽  
New Information ◽  
Ecological Association ◽  
Biological Aspects

Abstract Hyoliths are extinct enigmatic organisms of early lophotrochozoan affinity known globally from the Palaeozoic Era and were especially diverse and abundant in the Cambrian Period. However, the commonly incomplete preservation of hyolith exoskeletons and our limited knowledge of their soft anatomy makes their ecological and biological aspects unclear. Konservat-Lagerstätte are crucial windows to unlock the mysteries of hyoliths. Here we report a new occurrence of exceptionally preserved hyolithid hyoliths from the middle Cambrian Mantou Formation (Miaolingian, Wuliuan) in Shandong Province, North China. The preserved soft organs of the new species Novakotheca weifangensis sp. nov. include a U-shaped gut and possible pharynx, oesophagus, stomach and digestive gland, which provide significant new information for the reconstruction of the digestive system of hyolithids. Two taphonomic modes of hyoliths described herein are recognized: soft tissue preservation through pyritization and three-dimensional shell preservation through phosphatization. Morphological variations due to different preservational pathways in the same species are revealed, highlighting the taphonomic bias on taxonomy. The ecological association between hyoliths and small brachiopod epibionts is a direct example of species interactions, providing insights into the ecological structures and adaptability of early animals during Cambrian time.

A new soft-bodied fauna: The Pioche Formation of Nevada

2003 ◽  
Vol 77 (4) ◽  
pp. 674-690 ◽  
Author(s):  
Bruce S. Lieberman
Keyword(s):  
Early Cambrian ◽  
Burgess Shale ◽  
Middle Cambrian ◽  
Comprehensive Review ◽  
Geographic Ranges ◽  
New Information ◽  
Lincoln County

A new Burgess Shale-type soft-bodied fauna crossing the Lower-Middle Cambrian boundary in the Comet Shale Member of the Pioche Formation in Lincoln County, Nevada, contains common remains of soft-bodied ecdysozoan taxa. These fossils provide important new information about the nature and variety of Cambrian soft-bodied organisms. Arthropod taxa include one species of Canadaspis Novozhilov in Orlov, 1960, one species of ?Perspicaris Briggs, 1977, three species of Tuzoia Walcott, 1912, and at least two species of Anomalocaris Whiteaves, 1892. A priapulid referable to Ottoia Walcott, 1911a, was also recovered. A comprehensive review of Tuzoia is given. Some specimens from Early Cambrian sections are replaced by hematite, resulting in iron staining similar to that in such other Early Cambrian soft-bodied faunas as the Kinzers Formation in Pennsylvania. Some taxa in the Comet Shale, and in other Early and Middle Cambrian soft-bodied faunas, have prodigious geographic ranges that spanned much of Laurentia and even other Cambrian cratons. Moreover, these taxa ranged across the Early-Middle Cambrian boundary relatively unscathed. This is in contrast to many trilobite taxa that had narrow geographic ranges in the Early Cambrian and high levels of extinction at the Early-Middle Cambrian boundary.

New artiopodan arthropods from the early Cambrian Emu Bay Shale Konservat-Lagerstätte of South Australia

2012 ◽  
Vol 86 (2) ◽  
pp. 340-357 ◽  
Author(s):  
John R. Paterson ◽  
Diego C. García-Bellido ◽  
Gregory D. Edgecombe
Keyword(s):  
Alimentary Tract ◽  
Three Dimensional ◽  
Cladistic Analysis ◽  
South Australia ◽  
First Record ◽  
Early Cambrian ◽  
Burgess Shale ◽  
Early Devonian ◽  
New Information ◽  
Stage 4

The Emu Bay Shale Konservat-Lagerstätte (Cambrian Series 2, Stage 4) on Kangaroo Island, South Australia, is the source of two new non-biomineralized artiopodan arthropods. Squamacula buckorum n. sp. is the first record outside of China of a genus otherwise known only from its type species, S. clypeata, from the Chengjiang biota. The Australian species displays the long cephalic doublure and spiniform exopod setae that are apomorphic for this genus, provides new information on the alimentary tract and midgut glands (the latter preserved as three-dimensional, permineralized structures), and indicates interspecific variability in trunk segment numbers. The distribution of Squamacula strengthens the biogeographic connections between early Cambrian “Burgess Shale-type” biotas of Australia and South China. Australimicola spriggi n. gen. n. sp. represents a monotypic genus resolved in a cladistic analysis of Cambro-Ordovician artiopodans as most closely related to or within Conciliterga (a clade containing Helmetia, Kuamaia, Kwanyinaspis, Rhombicalvaria, Saperion, Skioldia, and Tegopelte). Compared with other members of this clade from Chengjiang and the Burgess Shale, the new genus is diagnosed by an elongate trunk with 23 thoracic tergites having spatulate pleural tips and a small pygidium possessing a single, elongate pair of pleural spines, with specimens also showing a hypostome attached to an anterior (or prehypostomal) sclerite, antennae, short endopods, an annulated alimentary tract, and a series of three-dimensional, permineralized midgut glands. An alternative relationship between Australimicola and the Early Ordovician–Early Devonian Cheloniellida explains the shared anterior flexure of trunk pleurae but forces dubious homologies in other characters, such as dorsally-articulated furcae versus spines.

Polypleuraspis (Arthropoda, Trilobita) from the middle Cambrian (Miaolingian Series) around Kane Basin (Nunavut and Greenland)

2020 ◽  
Vol 57 (1) ◽  
pp. 16-24
Author(s):  
John S. Peel
Keyword(s):  
British Columbia ◽  
New Species ◽  
North American ◽  
Type Species ◽  
Wood Formation ◽  
Ellesmere Island ◽  
Burgess Shale ◽  
Middle Cambrian ◽  
Shale Formation ◽  
A New Species

Polypleuraspis Poulsen, 1927, originally established on the basis of a single trilobite pygidium from the Cape Wood Formation of Inglefield Land, northwestern Greenland, is redescribed on the basis of material from additional occurrences in the Cape Wood and Telt Bugt formations exposed around Kane Basin in Ellesmere Island (Nunavut) and northern and northwestern Greenland. Polypleuraspis occurs together with Glossopleura Poulsen, 1927 in the Glossopleura walcotti Poulsen, 1927 Biozone of the Delamaran Stage of North American (Laurentian) usage, in middle Cambrian strata (Miaolingian Series) of the Wuliuan Stage. The type species, Polypleuraspis solitaria Poulsen, 1927, is compared with Polypleuraspis insignis Rasetti, 1951 from the Stephen Formation (Burgess Shale Formation) of British Columbia and to a new species from the Telt Bugt Formation of Daugaard-Jensen Land: Polypleuraspis glacialis sp. nov. Polypleuraspis cooperi Robison and Babcock, 2011, from the Spence Shale of Utah of similar age, is assigned to Polypleuraspidella gen. nov.

scholarly journals Skimming the surface with Burgess Shale arthropod locomotion

2011 ◽  
Vol 279 (1733) ◽  
pp. 1613-1620 ◽  
Author(s):  
Nicholas J. Minter ◽  
M. Gabriela Mángano ◽  
Jean-Bernard Caron
Keyword(s):  
Direct Evidence ◽  
The Body ◽  
Sedimentation Rates ◽  
Burgess Shale ◽  
Middle Cambrian ◽  
Ecological Information ◽  
Mode Of Life ◽  
Bottom Waters ◽  
Shale Formation ◽  
Chengjiang Biota

The first arthropod trackways are described from the Middle Cambrian Burgess Shale Formation of Canada. Trace fossils, including trackways, provide a rich source of biological and ecological information, including direct evidence of behaviour not commonly available from body fossils alone. The discovery of large arthropod trackways is unique for Burgess Shale-type deposits. Trackway dimensions and the requisite number of limbs are matched with the body plan of a tegopeltid arthropod. Tegopelte , one of the rarest Burgess Shale animals, is over twice the size of all other benthic arthropods known from this locality, and only its sister taxon, Saperion , from the Lower Cambrian Chengjiang biota of China, approaches a similar size. Biomechanical trackway analysis demonstrates that tegopeltids were capable of rapidly skimming across the seafloor and, in conjunction with the identification of gut diverticulae in Tegopelte , supports previous hypotheses on the locomotory capabilities and carnivorous mode of life of such arthropods. The trackways occur in the oldest part (Kicking Horse Shale Member) of the Burgess Shale Formation, which is also known for its scarce assemblage of soft-bodied organisms, and indicate at least intermittent oxygenated bottom waters and low sedimentation rates.

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