scholarly journals Early Cambrian record of failed durophagy and shell repair in an epibenthic mollusc

2007 ◽  
Vol 3 (3) ◽  
pp. 314-317 ◽  
Author(s):  
Christian B Skovsted ◽  
Glenn A Brock ◽  
Anna Lindström ◽  
John S Peel ◽  
John R Paterson ◽  
...  
Keyword(s):  
Fossil Record ◽  
Direct Evidence ◽  
Driving Forces ◽  
South Australia ◽  
Early Cambrian ◽  
Metazoan Evolution ◽  
Flinders Ranges ◽  
Shell Repair ◽  
Early Metazoan

Predation is arguably one of the main driving forces of early metazoan evolution, yet the fossil record of predation during the Ediacaran–Early Cambrian transition is relatively poor. Here, we present direct evidence of failed durophagous (shell-breaking) predation and subsequent shell repair in the Early Cambrian (Botoman) epibenthic mollusc Marocella from the Mernmerna Formation and Oraparinna Shale in the Flinders Ranges, South Australia. This record pushes back the first appearance of durophagy on molluscs by approximately 40 Myr.

A new arthropod Pygmaclypeatus daziensis from the Early Cambrian Chengjiang Lagerstätte, South China

2000 ◽  
Vol 74 (5) ◽  
pp. 979-982 ◽  
Author(s):  
Xingliang Zhang ◽  
Jian Han ◽  
Degan Shu
Keyword(s):  
South China ◽  
Fossil Record ◽  
South Australia ◽  
Early Cambrian ◽  
Burgess Shale ◽  
Closely Related Species ◽  
Stratigraphic Position ◽  
Chengjiang Lagerstätte ◽  
Early Metazoan ◽  
North Greenland

The early Cambrian Chengjiang Lagerstatte, generally regarded as late Atdabanian (Qian and Bengtson, 1989; Bengtson et al., 1990), has become celebrated for perhaps the earliest biota of soft-bodied organisms known from the fossil record and has proven to be critical to our understanding of early metazoan evolution. The Sirius Passet fauna from Peary Land, North Greenland, another important repository of soft-bodied and poorly sclerotized fossils, was also claimed as Early Cambrian (Conway Morris et al., 1987; Budd, 1995). The exact stratigraphic position of the Sirius Passet fauna (Buen Formation) is still uncertain, although the possibility of late Atdabanian age was proposed (Vidal and Peel, 1993). Recent work dates it in the “Nevadella” Biozone (Budd and Peel, 1998). It therefore appears to be simultaneous with or perhaps slightly younger than Chengjiang Lagerstatte, Eoredlichia Biozone (Zhuravlev, 1995). The Emu Bay Shale of Kangaroo Island, South Australia, has long been famous as a source of magnificent specimens of the trilobites Redlichia takooensis and Hsunaspis bilobata. It is additionally important as the only site in Australia so far to yield a Burgess-Shale-type biota (Glaessner, 1979; Nedin, 1992). The Emu Bay Shale was considered late Early Cambrian in age (Daily, 1956; Öpik, 1975). But Zhang et al.(1980) reassessed its age based on data from the Chinese Early Cambrian. The occurrence of Redlichia takooensis and closely related species of Hsunaspis indicates an equivalence to the Tsanglangpuian in the Chinese sequence, and the contemporary South Australia fauna correlate with the Botomian of Siberia (Bengtson et al., 1990). Thus the Emu Bay Shale is younger than the upper Atdabanian Chengjiang Lagerstatte, Chiungchussuian.

scholarly journals A new early Cambrian bradoriid (Arthropoda) assemblage from the northern Flinders Ranges, South Australia

2014 ◽  
Vol 25 (1) ◽  
pp. 420-437 ◽  
Author(s):  
Marissa J. Betts ◽  
Timothy P. Topper ◽  
James L. Valentine ◽  
Christian B. Skovsted ◽  
John R. Paterson ◽  
...  
Keyword(s):  
South Australia ◽  
Early Cambrian ◽  
Flinders Ranges

Occurrence of the siliceous sponge spicule Konyrium (Hexactinellida) in the upper Cambrian of the Mackenzie Mountains, northwestern Canada

2002 ◽  
Vol 76 (3) ◽  
pp. 565-569 ◽  
Author(s):  
Brian R. Pratt
Keyword(s):  
Fossil Record ◽  
Southern China ◽  
South Australia ◽  
Early Cambrian ◽  
Siliceous Sponge ◽  
Sponge Spicule ◽  
Animal Phyla ◽  
Sponge Diversity ◽  
Siliceous Sponges ◽  
Late Neoproterozoic

The fossil record of siliceous sponges—Hexactinellida and demosponge “Lithistida”—hinges upon both body fossils plus isolated spicules mostly recovered from limestones by acid digestion. The earliest record of siliceous sponge spicules extends back to the late Neoproterozoic of Hubei, southern China (Steiner et al., 1993) and Mongolia (Brasier et al., 1997), and body fossils attributed to the hexactinellids have been described from the Ediacaran of South Australia (Gehling and Rigby, 1996); thus they are the oldest-known definite representatives of extant animal phyla. The Early Cambrian saw a remarkable diversification in spicule morphology, with the appearance of an essentially “modern” array of forms (Zhang and Pratt, 1994). While a diversity decline may have occurred with the late Early Cambrian extinction(s), the subsequent Paleozoic and Mesozoic fossil record of spicules shows a relatively consistent range of morphologies (e.g., Mostler, 1986; Bengtson et al., 1990; Webby and Trotter, 1993; Kozur et al., 1996; Zhang and Pratt, 2000). However, because spicule form is not restricted to individual taxa and many sponge species secrete a variety of spicule shapes, it is difficult to gauge true siliceous sponge diversity and to explore their biostratigraphic utility using only isolated spicules.

scholarly journals Mollusc fauna of the Early Cambrian Bastion Formation of North-East Greenland

2004 ◽  
Vol 51 ◽  
pp. 11-37 ◽  
Author(s):  
Christian B. Skovsted
Keyword(s):  
United States ◽  
Fossil Record ◽  
South Australia ◽  
Early Cambrian ◽  
Eastern United States ◽  
East Greenland ◽  
North East ◽  
Considerable Detail

A diverse mollusc fauna from the Bastion Formation (Early Cambrian, middle Dyeran Stage) of North-East Greenland includes fifteen species (thirteen helcionelloids and two bivalves), adding considerable detail to the known fossil record of Early Cambrian molluscs from Laurentia. The occurrence of secondarily phosphatized shell surfaces together with phosphatic internal moulds in acid resistant residues allows new morphological details to be observed in several taxa. The fauna shows affinity to contemporaneous faunas from the Taconic allochthon of the eastern United States, but also to mollusc faunas of South Australia, China and Europe. The following new helcionelloid taxa are described: Capitoconus inclinatus n. gen. and n. sp. Capitoconus artus n. sp., Figurina groenlandica n. sp. and Latouchella ostenfeldense n. sp.

scholarly journals Humble origins for a successful strategy: complete enrolment in early Cambrian olenellid trilobites

2013 ◽  
Vol 9 (5) ◽  
pp. 20130679 ◽  
Author(s):  
Javier Ortega-Hernández ◽  
Jorge Esteve ◽  
Nicholas J. Butterfield
Keyword(s):  
Environmental Conditions ◽  
Fossil Record ◽  
Direct Evidence ◽  
Morphological Features ◽  
Early Cambrian ◽  
Defence Mechanism ◽  
Successful Strategy ◽  
New Information ◽  
Adverse Environmental Conditions ◽  
Morphological Ability

Trilobites are typified by the behavioural and morphological ability to enrol their bodies, most probably as a defence mechanism against adverse environmental conditions or predators. Although most trilobites could enrol at least partially, there is uncertainty about whether olenellids—among the most phylogenetically and stratigraphically basal representatives—could perform this behaviour because of their poorly caudalized trunk and scarcity of coaptative devices. Here, we report complete—but not encapsulating—enrolment for the olenellid genus Mummaspis from the early Cambrian Mural Formation in Alberta, the earliest direct evidence of this strategy in the fossil record of polymerid trilobites. Complete enrolment in olenellids was achieved through a combination of ancestral morphological features, and thus provides new information on the character polarity associated with this key trilobite adaptation.

Shelly fossils from the Early Cambrian (Toyonian) Wirrealpa, Aroona Creek, and Ramsay Limestones of South Australia

1993 ◽  
Vol 67 (5) ◽  
pp. 758-787 ◽  
Author(s):  
Glenn A. Brock ◽  
Barry J. Cooper
Keyword(s):  
Sequence Stratigraphy ◽  
Siberian Platform ◽  
South Australia ◽  
Early Cambrian ◽  
Middle Cambrian ◽  
Marine Transgression ◽  
Small Shelly Fossils ◽  
Flinders Ranges ◽  
Yorke Peninsula

Small shelly fossils from the Wirrealpa and Aroona Creek Limestones, Flinders Ranges, and the temporally equivalent Ramsay Limestone, Yorke Peninsula, South Australia, are described and assessed. These formations, deposited during a widespread marine transgression, have traditionally been assigned an early Middle Cambrian age based on lateral facies relationships, lithostratigraphic interpretation, and age diagnostic trilobites. However, new data from regional sequence stratigraphy and mounting paleontological evidence suggest that a late Early Cambrian age (equivalent to the Toyonian Stage from the Siberian Platform) is more appropriate for these units. Twenty-four taxa, including a number of problematica, poriferans, coeloscleritophorans, palaeoscolecidans, “conodontomorphs,” hyolithelminthes, hyoliths, mollusks, and inarticulate brachiopods, are reported herein; many of these have not previously been reported from the Cambrian of South Australia. The enigmatic Chalasiocranos exquisitum n. gen. and sp., known from disarticulated tuberculate cone-shaped phosphatic sclerites, and Protomelission gatehousei n. gen. and sp., a problematic, perhaps colonial organism, known from phosphatic plates, are especially notable. The genus Kaimenella is formally included in the Palaeoscolecida, and two species (including K. dailyi n. sp.) are recognized.

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