Burgess Shale Biota Research Articles

Unveiling the ventral morphology of a rare early Cambrian great appendage arthropod from the Chengjiang biota of China

BackgroundThe early Cambrian arthropod clade Megacheira, also referred to as great appendage arthropods, comprised a group of diminutive and elongated predators during the early Palaeozoic era, around 518 million years ago. In addition to those identified in the mid-Cambrian Burgess Shale biota, numerous species are documented in the renowned 518-million-year-old Chengjiang biota of South China. Notably, one species, Tanglangia longicaudata, has remained inadequately understood due to limited available material and technological constraints. In this study, we, for the first time, examined eight fossil specimens (six individuals) utilizing state-of-the-art μCT and computer-based 3D rendering techniques to unveil the hitherto hidden ventral and appendicular morphology of this species.ResultsWe have identified a set of slender endopodites gradually narrowing distally, along with a leaf-shaped exopodite adorned with fringed setae along its margins, and a small putative exite attached to the basipodite. Our techniques have further revealed the presence of four pairs of biramous appendages in the head, aligning with the recently reported six-segmented head in other early euarthropods. Additionally, we have discerned two peduncle elements for the great appendage. These findings underscore that, despite the morphological diversity observed in early euarthropods, there exists similarity in appendicular morphology across various groups. In addition, we critically examine the existing literature on this taxon, disentangling previous mislabelings, mentions, descriptions, and, most importantly, illustrations.ConclusionsThe μCT-based investigation of fossil material of Tanglangia longicaudata, a distinctive early Cambrian euarthropod from the renowned Chengjiang biota, enhances our comprehensive understanding of the evolutionary morphology of the Megacheira. Its overall morphological features, including large cup-shaped eyes, raptorial great appendages, and a remarkably elongated telson, suggest its potential ecological role as a crepuscular predator and adept swimmer in turbid waters.

Porifera and Chancelloriidae of the Cambrian of Sonora, Mexico: A review

Archaeocyaths, articulated reticulosans, protospongiid sponge spicules, fragments of chancelloriid scleritomes and isolated sclerites are typical components of the lower-middle Cambrian Sonora biota of Mexico. This report briefly introduces the Cambrian sponges and chancelloriid fossils of the Sonoran platform described and illustrated to date.Early Cambrian (Series 2, stages 3 and 4) sponge spicules, Kiwetinokia sp. and extinct sponge-like archaeocyaths occur in the Puerto Blanco Formation, at the Cerro Clemente and Cerro Rajón in the Caborca region, northwest Sonora. Besides, a variety of chancelloriid sclerites belonging to Chancelloria, Allonia, and Archiasterella have been described in that region. Also, Chancelloria sclerites have been documented in the Arrojos Formation of the Caborca region.A fauna of hexactinellid sponges and chancelloriids was recorded from the middle Cambrian (Wuliuan Stage, Miaolingian Series) strata from the Arivechi section, in the eastern part, and San José de Gracia and El Sahural sections in the central Sonora. The middle Cambrian El Mogallón Formation in the Arivechi area yield assemblages of reticulosan thin-wall sponges, isolated protospongiid spicules and chancelloriid sclerite morphotypes. Fragments of articulated scleritomes of Chancelloria eros were reported for the first time for the Cambrian of Mexico, and sclerites of Allonia and Archiasterella in the Cerro El Sahuaral near San José de Gracia. Protospongiid spicules and isolated sclerites of chancelloriids were determined in the Cerro El Chihuarruita section at the San José de Gracia area.The mid-Cambrian Sonoran faunas have been compared with the Burgess Shale biota in Canada, and those of the Utah formations, in the USA localized around the Laurentia. Nevertheless, as the chancelloriid fauna is cosmopolitan, some of these genera are also present in other palaeocontinent including Siberia, China, and Australia.Sponges and chancelloriids are an important biotic component of the Sonoran communities. Their discovery constitutes a valuable tool for the reconstruction of the faunas, their paleoecology and paleoenvironments. These findings expand the paleogeographical distribution of these faunas during the Cambrian in the warm platform of Sonora.

First occurrence of the Cambrian arthropodSidneyiaWalcott, 1911 outside of Laurentia

AbstractThe arthropodSidneyiaWalcott, 1911 is a remarkable animal of the Burgess Shale biota (Cambrian Miaolingian, Wuliuan; British Columbia, Canada), which has not been confidently reported from other Cambrian Konservat-Lagerstätten. Here we report the discovery ofSidneyiacf.inexpectansfrom the Wuliuan Mantou Formation of North China, which substantially expands the known palaeogeographical distribution of this genus. Our discovery suggests thatSidneyiahad much greater dispersal ability than hitherto thought. It also confirms the presence of exceptionally preserved fossils in the Wuliuan Mantou Formation, one of the rare Burgess Shale-type deposits of North China.

Waptia fieldensis Walcott, a mandibulate arthropod from the middle Cambrian Burgess Shale.

Waptia fieldensis Walcott, 1912 is one of the iconic animals from the middle Cambrian Burgess Shale biota that had lacked a formal description since its discovery at the beginning of the twentieth century. This study, based on over 1800 specimens, finds that W. fieldensis shares general characteristics with pancrustaceans, as previous authors had suggested based mostly on its overall aspect. The cephalothorax is covered by a flexible, bivalved carapace and houses a pair of long multisegmented antennules, palp-bearing mandibles, maxillules, and four pairs of appendages with five-segmented endopods—the anterior three pairs with long and robust enditic basipods, the fourth pair with proximal annulations and lamellae. The post-cephalothorax has six pairs of lamellate and fully annulated appendages which appear to be extensively modified basipods rather than exopods. The front part of the body bears a pair of stalked eyes with the first ommatidia preserved in a Burgess Shale arthropod, and a median ‘labral’ complex flanked by lobate projections with possible affinities to hemi-ellipsoid bodies. Waptia confirms the mandibulate affinity of hymenocarines, retrieved here as part of an expanded Pancrustacea, thereby providing a novel perspective on the evolutionary history of this hyperdiverse group. We construe that Waptia was an active swimming predator of soft prey items, using its anterior appendages for food capture and manipulation, and also potentially for clinging to epibenthic substrates.

A new vauxiid sponge from the Kaili Biota (Cambrian Stage 5), Guizhou, South China

AbstractThe skeleton of a new vauxiid sponge (Order Verongida),Angulosuspongia sinensisgen. et sp. nov., described on the basis of material from calcareous mudstones of the Kaili Formation (Cambrian Stage 5), Jianhe area, Guizhou, South China, is composed of two layers of fused spicules outlining hexagonal or polygonal openings. These vauxiid remains are the first reported from outside Laurentia, and represent only the second genus attributed to the family. Its age is close to but still slightly older than the Burgess Shale Biota, and it appears to be a primitive relative of other members of the Vauxiidae. The morphological differences between Chinese and Laurentian vauxiid sponges may be a result of vicariance. These specimens not only extend the geographic distribution of vauxiids, but also help to fill a chronostratigraphical gap between North Greenland and North American material and provide additional evidence for understanding the evolutionary history of the Demospongiae.

A new Burgess Shale-type deposit from the Ediacaran of western Mongolia.

Preservation of soft-bodied organisms is exceedingly rare in the fossil record. One way that such fossils are preserved is as carbonaceous compressions in fined-grained marine sedimentary rocks. These deposits of exceptional preservation are known as Burgess Shale-type (BST) deposits. During the Cambrian Period, BST deposits are more common and provide a crucial view of early animal evolution. The earliest definitive fossil evidence for macroscopic animal-grade organisms is found in the preceding Ediacaran Period. BST deposits from the Ediacaran are rarer and lack conclusive evidence for animals. Here we report the discovery of a new Ediacaran BST deposit with exceptional preservation of non-mineralizing macro-organisms in thinly bedded black shale from Zavkhan Province, western Mongolia. This fossil assemblage, here named the Zuun-Arts biota, currently consists of two new species of probable macroscopic multicellular benthic algae. One species, Chinggiskhaania bifurcata n. gen., n. sp., dominates the biota. The other species, Zuunartsphyton delicatum n. gen., n. sp., is known from three specimens. SEM-EDS analysis shows that the fossils are composed of aluminosilicate clay minerals and some carbon, a composition comparable to fossils from the Cambrian Burgess Shale biota. This discovery opens a new window through which to view late Precambrian life.

TAPHONOMY AND DEPOSITIONAL SETTING OF THE BURGESS SHALE TULIP BEDS, MOUNT STEPHEN, BRITISH COLUMBIA

ABSTRACT Burgess Shale–type deposits represent exceptional preservational windows for examining the biodiversity and ecological structure of some of the earliest metazoan communities that evolved during the Cambrian Explosion. While much attention has been paid to the original Burgess Shale locality, the Walcott Quarry on Fossil Ridge, temporal and regional variations of the depositional environment of the Burgess Shale biota as a whole are still poorly understood. Here we present the first comprehensive taphonomic and sedimentological study of the Tulip Beds on Mount Stephen (Campsite Cliff Shale Member, Burgess Shale Formation), based on a time-averaged assemblage of nearly 10,000 specimens. The taphonomic characteristics—size sorting, resistance to decay, and potential flow alignment—and mode of deposition of this assemblage are compared specifically to those of the nearby and stratigraphically younger Walcott Quarry assemblage. Like other Burgess Shale–type deposits, the Tulip Beds consist of millimet...

Diversity and species abundance patterns of the Early Cambrian (Series 2, Stage 3) Chengjiang Biota from China

Lagerstättenfrom the Precambrian–Cambrian transition have traditionally been a relatively untapped resource for understanding the paleoecology of the “Cambrian explosion.” This quantitative paleoecological study is based on 10,238 fossil specimens belonging to 100 animal species, 11 phyla, and 15 ecological categories from the lower Cambrian (Series 2, Stage 3) Chengjiang biota (Mafang locality near Haikou, Yunnan Province, China). Fossils were systematically collected within a 2.5-meter-thick sequence divided into ten stratigraphic intervals. Each interval represents an induced time-averaged assemblage of various event (obrution) beds of unknown duration. Overall, the different fossil assemblages are taxonomically and ecologically similar, suggesting the presence of a single community type recurring throughout the Mafang section. The Mafang community is dominated by epibenthic vagile hunters or scavengers, sessile suspension feeders, and infaunal vagile hunters or scavengers represented primarily by arthropods, brachiopods, and priapulids, respectively. Most species have low abundance and low occurrence frequencies, whereas a few species are numerically abundant and occur frequently. Overall, in structure and ecology the Mafang community is comparable to the Middle Cambrian (Series 3, Stage 5) Burgess Shale biota (Walcott Quarry, Yoho National Park, British Columbia, Canada). This suggests that, despite variations in species identity within taxonomic and ecological groups, the structure and ecology of Cambrian Burgess Shale-type communities remained relatively stable until at least the Middle Cambrian (Series 3, Stage 5) in subtidal to relatively deep-water offshore settings in siliciclastic soft-substrate environments.

The Cambrian explosion: the construction of animal biodiversity

In 1909 Charles Walcott discovered the remarkable soft-bodied animal fauna of the Middle Cambrian age Burgess Shale in British Columbia. These fossils have become the iconic representation of the astonishing expansion of animal diversity during the Cambrian, including the first appearance in the fossil record of essentially all living phyla, known as the “Cambrian explosion.” Although the Burgess Shale biota is the public face of the Cambrian explosion, even appearing on a 1995 cover of Time, it is only a small part of the story (and somewhat late in the tale). Most readers will be familiar with the Cambrian explosion through Stephen Jay Gould’s 1989 book Wonderful Life (1989) or perhaps Martin Brasier’s more recent Darwin’s Lost World (2009). Both of these books were written to reach a general audience. What has been lacking to date is a more technical book, aimed at students and professionals, which summarizes and introduces the tremendous amount of research that this episode of earth history has received in the last 25 years. The Cambrian Explosion: The Construction of Animal Biodiversity by Douglas H Erwin and James W Valentine more than fills this need. It will become required reading for anyone who wants to understand the multiple lines of evidence, from geology, geochemistry, paleontology, genetics, phylogenetics, comparative morphology, and ecology, that have to be integrated to understand one of the most important episodes in the history of life. The authors, both paleontologists, are deeply respected authorities on evolution and the Cambrian fossil record, with a welldeserved reputation for innovative approaches. This book necessarily covers a tremendous amount of ground; the forty-two pages of references demonstrate the depth and breadth of scholarship that the authors summarize. The first section covers the geological context of the explosion, stretching back to the Snowball Earth episodes of the Cryogenian. This includes summaries of the current status of the absolute and relative time scales for this period and what geochemical proxies reveal about ocean chemistry, including oxygenation states and changes in the carbon cycle. The latter is unfortunately the weakest part of the book; there is very poor integration between figures (which come from external sources) and text; the figure captions and labels are inadequate. The book hits its stride in the next section. It begins with a brief review of phylogenetics and of living metazoan morphology and relationships, a subject Valentine explored in more depth in his comprehensive earlier book, On the Origin of Phyla (2004). This is followed

Hemichordata (Pterobranchia, Enteropneusta) and the fossil record

The Hemichordata are generally interpreted as early deuterostomes, closely related to the chordates, a notion important for modern analyses of the origin of the deuterostomes. Because their fossil record is quite scanty, modern phylogenetic interpretations largely rely on the analysis of DNA of the available extant taxa. The tripartite body plan of the group of worm-like hemichordates, the Enteropneusta, may be traced back in deep time to a few poorly known Middle Cambrian (Series 3, Stage 5) taxa from the Burgess Shale biota. The derived small, colonial or pseudocolonial Pterobranchia (Cephalodiscida and Graptolithina) have a more complete fossil record due to their preservable housing construction, the tubarium. The relationships of fossil taxa, putatively identified as early deuterostomes and possible hemichordates or even as pterobranchs of Lower to Middle Cambrian age (e.g. Galeaplumosus, Herpetogaster), cannot be substantiated. The Pterobranchia and their housing construction are first seen in the Middle Cambrian Series 3, Stage 5 but a clonal, colonial organization of the tubaria can only be recognized in the basal Drumian. The fossil enteropneust Mazoglossus ramsdelliBardack, 1997 from the Carboniferous Mazon Creek Biota is re-described, its lectotype designated and illustrated for the first time.

New Wiwaxia material from the Tsinghsutung Formation (Cambrian Series 2) of Eastern Guizhou, China

AbstractWiwaxia is an extinct early metazoan with uncertain affinities, which is well represented in strata of Cambrian Series 2–3 age. Well-preserved representatives of Wiwaxia are known from the Burgess Shale Biota and the Kaili Biota. Here, new material of Wiwaxia corrugata (Matthew, 1899) is reported from the upper part of the Tsinghsutung Formation (Cambrian Series 2) near Balang Village, Guizhou Province, China. These specimens have a close evolutionary relationship to Wiwaxia taijiangensis Zhao, Qian & Lee, 1994 from the overlying Kaili Formation. New Wiwaxia material from the Tsinghsutung Formation and observations of specimens with articulated individuals from the Kaili Formation suggest that Wiwaxia taijiangensis should be a junior synonym of W. corrugata. A new study indicates that W. corrugata has a wide geographic distribution, a short geological history and evolutionary uniqueness and provides new data on taphonomy of this genus.

Gut contents as direct indicators for trophic relationships in the Cambrian marine ecosystem.

Present-day ecosystems host a huge variety of organisms that interact and transfer mass and energy via a cascade of trophic levels. When and how this complex machinery was established remains largely unknown. Although exceptionally preserved biotas clearly show that Early Cambrian animals had already acquired functionalities that enabled them to exploit a wide range of food resources, there is scant direct evidence concerning their diet and exact trophic relationships. Here I describe the gut contents of Ottoia prolifica, an abundant priapulid worm from the middle Cambrian (Stage 5) Burgess Shale biota. I identify the undigested exoskeletal remains of a wide range of small invertebrates that lived at or near the water sediment interface such as hyolithids, brachiopods, different types of arthropods, polychaetes and wiwaxiids. This set of direct fossil evidence allows the first detailed reconstruction of the diet of a 505-million-year-old animal. Ottoia was a dietary generalist and had no strict feeding regime. It fed on both living individuals and decaying organic matter present in its habitat. The feeding behavior of Ottoia was remarkably simple, reduced to the transit of food through an eversible pharynx and a tubular gut with limited physical breakdown and no storage. The recognition of generalist feeding strategies, exemplified by Ottoia, reveals key-aspects of modern-style trophic complexity in the immediate aftermath of the Cambrian explosion. It also shows that the middle Cambrian ecosystem was already too complex to be understood in terms of simple linear dynamics and unique pathways.

New Bivalved Arthropods from Mid‐Cambrian Kaili Biota of Southeastern Guizhou, Southwest China

Abstract:Bivalved arthropods are very important elements in Mid‐Cambrian Kaili Biota. Three genera, Alicaris, Pseudoarctolepis, and Forfexicaris, are herein recorded for the first time, including three new species: Alicaris kailiensis sp. nov., Forfexicaris reticulata sp. nov., and Pseudoarctolepis semicircularis sp. nov., of which Alicaris kailiensis sp. nov. could be assigned to crustaceomorphs; the other two forms are grouped as proschizoramians. These forms provide important information about the distribution and species diversity of a poorly‐known element of Cambrian fauna, and also bridge the biotic evolutionary gap between Early Cambrian Chengjiang Biota in Southwest China and Mid‐Cambrian burgess shale biota in North America.

Dinomischus from the Middle Cambrian Kaili Biota, Guizhou, China

Abstract Dinomischus is a rare solitary epifaunal suspension feeder. The over-all morphology of Dinomischus consists of a conical calyx surrounded with elongate bracts and an elongate stem. Visceral mass and stomach sac are evident in the body cavity. Dinomischus is interpreted as a primative ancestor of living entoprocts based on similarities in morphology and mode of life. Previously, Dinomischus is only known in two localities: the mid-Middle Cambrian Burgess Shale Biota and the Early Cambrian Chengjiang Biota. A single specimen of Dinomischus cf. D. isolatus Cowry Morris, 1977 from the Kaili Biota, Guizhou, China is reported here. The discovery of Dinomischus in the Kaili Biota extends its geographical range and indicated that the rare Dinomischus could tolerate deeper water settings during the Middle Cambrian.

A new Burgess Shale–type assemblage from the “thin” Stephen Formation of the southern Canadian Rockies

Research Article| September 01, 2010 A new Burgess Shale–type assemblage from the “thin” Stephen Formation of the southern Canadian Rockies Jean-Bernard Caron; Jean-Bernard Caron 1Department of Natural History-Palaeobiology, Royal Ontario Museum, 100 Queen's Park, Toronto, Ontario M5S 2C6, Canada Search for other works by this author on: GSW Google Scholar Robert R. Gaines; Robert R. Gaines 2Pomona College, Geology Department, 185 E. Sixth Street, Claremont, California 91711, USA Search for other works by this author on: GSW Google Scholar M. Gabriela Mángano; M. Gabriela Mángano 3Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada Search for other works by this author on: GSW Google Scholar Michael Streng; Michael Streng 4Department of Earth Sciences, Uppsala University, Villavägen 16, 75236 Uppsala, Sweden Search for other works by this author on: GSW Google Scholar Allison C. Daley Allison C. Daley 4Department of Earth Sciences, Uppsala University, Villavägen 16, 75236 Uppsala, Sweden Search for other works by this author on: GSW Google Scholar Geology (2010) 38 (9): 811–814. https://doi.org/10.1130/G31080.1 Article history received: 31 Jan 2010 rev-recd: 09 Apr 2010 accepted: 14 Apr 2010 first online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Jean-Bernard Caron, Robert R. Gaines, M. Gabriela Mángano, Michael Streng, Allison C. Daley; A new Burgess Shale–type assemblage from the “thin” Stephen Formation of the southern Canadian Rockies. Geology 2010;; 38 (9): 811–814. doi: https://doi.org/10.1130/G31080.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract A new Burgess Shale–type assemblage, from the Stephen Formation of the southern Canadian Rocky Mountains, is described herein. It occurs near Stanley Glacier in Kootenay National Park, 40 km southeast of the type area near Field, British Columbia. While at least a dozen Burgess Shale localities are known from the “thick” Stephen Formation, the Stanley Glacier locality represents the first discovery of Burgess Shale–type fossils from the “thin” Stephen Formation. The Cathedral Escarpment, an important regional paleotopographic feature, has been considered important to the paleoecologic setting and the preservation of the Burgess Shale biota. However, the Stanley Glacier assemblage was preserved in a distal ramp setting in a region where no evidence of an escarpment is present. The low-diversity assemblage contains eight new soft-bodied taxa, including the anomalocaridid Stanleycaris hirpex n. gen., n. sp. (new genus, new species). Nektonic or nektobenthic predators represent the most diverse group, whereas in relative abundance, the assemblage is dominated by typical Cambrian shelly benthic taxa. The low diversity of both the benthic taxa and the ichnofauna, which includes diminutive trace fossils associated with carapaces of soft-bodied arthropods, suggests a paleoenvironment with restrictive conditions. The Stanley Glacier assemblage expands the temporal and geographic range of the Burgess Shale biota in the southern Canadian Rockies, and suggests that Burgess Shale–type assemblages may be common in the “thin” Stephen Formation, which is regionally widespread. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

BURGESS SHALE-TYPE PRESERVATION: A COMPARISON OF NARAOIIDS (ARTHROPODA) FROM THREE CAMBRIAN LOCALITIES

The chemical composition of well-preserved naraoiids from the Chengjiang, Kaili, and Burgess Shale biotas is compared. Gut diverticulae in samples from all three biotas contain C, P, and Fe, indicating a primary composition of organic carbonaceous material, and the presence of apatite and pyrite as the result of authigenic mineralization in association with decay and early diagenetic processes. Gut traces from Burgess Shale specimens retain apatite and pyrite, as well as clay minerals, reflecting a history involving greenschist-grade metamorphism. Kaili specimens have been subjected to lower-grade metamorphism and, or thermal alteration, but alteration of pyrite pseudomorphs in the gut traces to limonite indicates the effect of weathering. Loss of sulfur and calcium, oxidation of pyrite, and the light color of the Chengjiang samples are the result of a greater degree of weathering than in specimens from the other two localities. As demonstrated here, Kaili samples serve as an important baseline for interpreting specimens from the Burgess Shale (high-grade metamorphism) and the Chengjiang (intense chemical weathering) deposits. Our study shows for the first time that the conservation of organic carbon is the common primary mode of soft-part preservation in naraoiid arthropods from these three signature Burgess Shale-type localities. Differences among these major deposits are a product of later diagenesis and weathering of the authigenic mineralization associated with the preservation of labile structures. Among the major constituents formed during diagenesis—carbonaceous material, calcium phosphate (e.g., apatite), and iron sulfide (e.g., pyrite)—the minerals are more susceptible to chemical weathering via hydrolysis.

Bioturbation in Burgess Shale-type Lagerstätten — Case study of trace fossil–body fossil association from the Kaili Biota (Cambrian Series 3), Guizhou, China

Cruziana, Gordia, Planolites, Rusophycus, and Trichophycus are common ichnological elements of the Kaili Biota. New discoveries based on the examination of 323 specimens include eldoniids, echinoderms, trilobites, monoplacophorans, and non-biomineralizing arthropods that are associated with trace fossils. Based on the observed effects of bioturbation on the preservation of five different animal groups, it is clear that infaunal scavengers/deposit feeders were periodically active on the Kaili sea floor and were able to reach historic layers yielding exceptionally preserved fossils. In general, the average level of infaunal activity is absent to moderate (Ichnofabric Index [i.i.] = 1 to 3) in the Kaili substrate; by contrast, the “ Phycodes beds” are completely disturbed by infaunal activity (i.i. = 5). Observed burrow diameter ranges from diminutive (∼ 0.2 mm) to normal (up to 4.2 mm). Computed tomography allows us to visualize the precise geometry of the trace fossil–body fossil association in three dimensions. We concluded that although some Kaili infaunal animals could bore through the biomineralized echinoderms, they did not appear to have scavenged upon these echinoderms based on our three-dimensional reconstruction. Furthermore, Kaili burrowers can reach the historic layers containing exceptionally preserved fossils without altering soft-tissue preservation. On the other hand, we used conventional techniques to reveal that one burrow is filled with fecal pellets (100–200 μm) at its terminal end. Because most burrows are filled with yellow/brown “coarse sediment”, and because there is no compositional difference between the fecal pellets and the surrounding coarse sediment within the burrow, the origin of the yellow/brown “coarse sediment” is interpreted here as parautochthonous and/or autochthonous and as a result of sediment reworking by deposit (or suspension) feeders. The relative scarcity of soft-part preservation in the Kaili Biota compared to the older Chengjiang Biota and the younger Burgess Shale Biota may be the result of post-burial bio-disturbance due to the relatively high intensity of local bioturbation. It is plausible that oxygenation in deeper sediments (facilitated by bioturbation) allowed carcasses in the Kaili biota to undergo a more extensive period of ‘normal’ decay prior to final burial than in other Cambrian Konservat- Lagerstätten.

Arthropod visual predators in the early pelagic ecosystem: evidence from the Burgess Shale and Chengjiang biotas

Exceptional fossil specimens with preserved soft parts from the Maotianshan Shale (ca 520 Myr ago) and the Burgess Shale (505 Myr ago) biotas indicate that the worldwide distributed bivalved arthropod Isoxys was probably a non-benthic visual predator. New lines of evidence come from the functional morphology of its powerful prehensile frontal appendages that, combined with large spherical eyes, are thought to have played a key role in the recognition and capture of swimming or epibenthic prey. The swimming and steering of this arthropod was achieved by the beating of multiple setose exopods and a flap-like telson. The appendage morphology of Isoxys indicates possible phylogenetical relationships with the megacheirans, a widespread group of assumed predator arthropods characterized by a pre-oral 'great appendage'. Evidence from functional morphology and taphonomy suggests that Isoxys was able to migrate through the water column and was possibly exploiting hyperbenthic niches for food. Although certainly not unique, the case of Isoxys supports the idea that off-bottom animal interactions such as predation, associated with complex feeding strategies and behaviours (e.g. vertical migration and hunting) were established by the Early Cambrian. It also suggests that a prototype of a pelagic food chain had already started to build-up at least in the lower levels of the water column.

Charles D. Walcott: A Few Comments on Stratigraphy and Sedimentation

Throughout his career, Charles D.Walcott was a prodigious scientist.Although perhaps best known for his contributions to our understanding of the Cambrian System, including discovery of the Burgess Shale Biota,Walcott made other important contributions to stratigraphy and sedimentology that have had a lasting impact. Some contributions seem to have been quite deliberate, whereas others may have been less conscious. Examples of his deliberate scientific efforts are: measuring and describing more than 8250 m (25,000 ft) of strata in Utah and Arizona; interpreting the origin of limestone breccia and conglomerate within a limestone matrix; calculation of geologic time from rates of sedimentary deposition; and consideration of the Ozarkian and Canadian as time periods. An interesting contribution that may have been less obvious is the observation that limestones could form quickly in shallow marine water.

C. D. Walcott - definitely a Rocky Mountain geologist

Profile of Rocky Mountain Geologist – a continuing series Charles Doolittle Walcott (1850–1927) (Fig. 1), was a great geologist, along with being a great paleontologist. Anyone who reads nothing more about him than his list of publications (Darton, 1928; Yochelson, 1967) ought to be impressed; providing references to papers resulting from Walcott's field efforts mentioned below would greatly exceed the word limit. His 1910 discovery of the Middle Cambrian Burgess Shale biota in eastern British Columbia certainly qualifies him as a Rocky Mountain geologist. For those who would view a paleontologist as not-quite a true geologist, Walcott's early years with the U.S. Geological Survey (USGS) show his mettle in the field, if the title may be expanded geographically to include the Colorado Plateau and Basin and Range province. Figure 1. Charles Doolittle Walcott, shortly after he was appointed third director of the U.S. Geological Survey; this picture is undated but was probably taken in 1894 or 1895. From Smithsonian Institution Archives number 82-3145. Employee number 20 entered duty with the USGS on July 21, 1879 (Yochelson, 1998). Before Walcott had time to reconsider career choice, he was borne by passenger train, freight train, stagecoach and mule, to Kanab in southwest Utah. His assignment was more or less straightforward, namely to measure a standard section of the regional rock column and collect fossils from the various stratigraphic units. With a couple of mules, and a camp hand/cook/ mule skinner, he set out for the fresh-water Tertiary strata of the Pink Cliffs, not far from present-day Bryce Canyon National Park. He began measuring downward until he reached the Colorado River, ending at the Cambrian sandstone. This was more than 13,000 feet of section! It was mid-November before Walcott returned to Washington. Only the Paleozoic strata were described and only in the most preliminary …