A new helcionelloid mollusk from the middle Cambrian Burgess Shale, Canada

2013 ◽  
Vol 87 (6) ◽  
pp. 1067-1070 ◽  
Author(s):  
Simon Conway Morris ◽  
John S. Peel

Burgess Shale-type faunas provide unique insights into the Cambrian “explosion”. Their degree of representativeness of Cambrian marine life in general is, however, less easy to establish. One line of evidence is to consider only the skeletal component of a Burgess Shale-type fauna and compare that with a typical Cambrian assemblage. This paper describes a new species of helcionelloid mollusk (Totoralia reticulata n. sp.) from the middle Cambrian Burgess Shale of British Columbia. Whilst much rarer than the co-occurring smooth shelled helcionelloid Scenella amii, the strongly costate morphology of Totoralia reinforces comparisons with Cambrian shelly faunas. The extension of the range of Totoralia from Argentina to Canada adds support to the proposed derivation of the Precordillera terrane of Mendoza from Laurentia.

2020 ◽  
Vol 57 (1) ◽  
pp. 16-24
Author(s):  
John S. Peel

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.


2015 ◽  
Vol 370 (1666) ◽  
pp. 20140313 ◽  
Author(s):  
Derek E. G. Briggs

Harry Whittington's 1975 monograph on Opabinia was the first to highlight how some of the Burgess Shale animals differ markedly from those that populate today's oceans. Categorized by Stephen J. Gould as a ‘weird wonder’ ( Wonderful life , 1989) Opabinia , together with other unusual Burgess Shale fossils, stimulated ongoing debates about the early evolution of the major animal groups and the nature of the Cambrian explosion. The subsequent discovery of a number of other exceptionally preserved fossil faunas of Cambrian and early Ordovician age has significantly augmented the information available on this critical interval in the history of life. Although Opabinia initially defied assignment to any group of modern animals, it is now interpreted as lying below anomalocaridids on the stem leading to the living arthropods. This commentary was written to celebrate the 350th anniversary of the journal Philosophical Transactions of the Royal Society .


2015 ◽  
Vol 89 (3) ◽  
pp. 411-423 ◽  
Author(s):  
Simon Conway Morris ◽  
Paul A. Selden ◽  
Glade Gunther ◽  
Paul G. Jamison ◽  
Richard A. Robison

AbstractCambrian strata of the Laurentian craton contain numerous examples of Burgess Shale–type faunas. Although displaying a more or less concentric distribution around the cratonal margin, most faunal occurrences are in present-day western North America, extending from the Northwest Territories to California. Nevertheless, the soft-bodied and lightly skeletalized fossils in most of these Lagerstätten are highly sporadic. Here, we extend knowledge of such Middle Cambrian occurrences in Utah with reports of four taxa. An arthropod from the Marjum Formation, Dytikosicula desmatae gen. et sp. nov., is a putative megacheiran. It is most similar to Dicranocaris guntherorum, best known from the younger Wheeler Formation, but differs primarily in the arrangement of pleurae and overall size. Along with a specimen of ?Yohoia sp, a new species of Yohoia, Y. utahana sp. nov., is described. It differs from the type and only known species, Y. tenuis, principally in its larger size and shorter exopods; it is the first description of this genus from outside the Burgess Shale. A new species of a stem-group lophotrochozoan from the Spence Shale, Wiwaxia herka sp. nov., possesses a palisade of dorso-lateral spines that are more robust and numerous than the type species of Wiwaxia, W. corrugata. Another notable taxon is Eldonia ludwigi from the Marjum Formation, which is interpreted as a primitive ambulacrarian (assigned to the cambroernids) and a new specimen of the ?cnidarian Cambrorhytium from the Wheeler Shale is illustrated.


2008 ◽  
Vol 82 (2) ◽  
pp. 238-254 ◽  
Author(s):  
Derek E. G. Briggs ◽  
Bruce S. Lieberman ◽  
Jonathan R. Hendricks ◽  
Susan L. Halgedahl ◽  
Richard D. Jarrard

The Middle Cambrian Spence Shale Member (Langston Formation) and Wheeler and Marjum Formations of Utah are known to contain a diverse soft-bodied fauna, but important new paleontological material continues to be uncovered from these strata. New specimens of anomalocaridids include the largest and smallest near complete examples yet reported from Utah. New material of stem group arthropods includes two new genera and species of arachnomorphs: Nettapezoura basilika and Dicranocaris guntherorum. Other new arachnomorph material includes a new species of Leanchoilia comparable to L. protogonia Simonetta, 1970; Leanchoilia superlata? Walcott, 1912; Sidneyia Walcott, 1911a; and Mollisonia symmetrica Walcott, 1912. L. protogonia from the Burgess Shale is confirmed as a separate species and is not a composite fossil. The first example of the trilobite Elrathia kingii preserving traces of the appendages is described. In addition, new material of the bivalved arthropods Canadaspis Novozhilov in Orlov, 1960; Branchiocaris Briggs, 1976; Waptia Walcott, 1912; and Isoxys Walcott, 1890 is described.


2016 ◽  
Vol 91 (2) ◽  
pp. 265-293 ◽  
Author(s):  
Gerd Geyer ◽  
John S. Peel

AbstractThe richly fossiliferous Ekspedition Bræ Formation of North Greenland yields a typical oligospecific fossil assemblage with well-preserved trilobites, helcionelloids, and lingulate brachiopods. The trilobites includeItagnostus subhastatusnew species,Itagnostussp. cf.I.gaspensis(Rasetti, 1948),Elrathina aphroditenew species,Elrathina athenanew species,Elrathina heranew species, andElrathia groenlandicanew species—a fossil assemblage typical of theBathyuriscus-ElrathinaZone as known from the Cordilleran regions of Laurentia. Excellent preservation allows a detailed assessment of the prosopon and elucidates aspects of the ontogenetic development ofElrathinaandElrathia. An evaluation ofElrathinaincludes a redescription of its type species,E.cordillerae(Rominger, 1887), based on the type material, and indicates that most specimens collected from the Burgess Shale and previously dealt with asE.cordilleraerepresent a new species.


2017 ◽  
Vol 91 (5) ◽  
pp. 902-910 ◽  
Author(s):  
Julien Kimmig ◽  
Luke C. Strotz ◽  
Bruce S. Lieberman

AbstractWe describe a new species of enigmatic stalked filter feeder, Siphusauctum lloydguntheri, from the middle Cambrian (Series 3, Stage 5) Antimony Canyon locality of the Spence Shale of northern Utah. The described specimen is the only one known from the Spence Shale, represents the first occurrence of Siphusauctum outside the Burgess Shale, and is only the second described species from the genus. Siphusauctum lloydguntheri n. sp. differs from S. gregarium O’Brien and Caron, 2012 in the shape of its calyx and the position of the digestive tract. The new species provides some additional information about the possible affinities of enigmatic stalked Cambrian filter feeders, as well as the taphonomic pathways that lead to preservation of Siphusauctum.


2004 ◽  
Vol 78 (6) ◽  
pp. 1138-1145 ◽  
Author(s):  
Jean-Bernard Caron ◽  
David M. Rudkin ◽  
Stuart Milliken

The discovery of a new naraoiid nektaspid in the Upper Silurian (Pridolian) of southeastern Ontario significantly extends the range of this unusual group. Nektaspids are nonmineralized arthropods typical of Early and Middle Cambrian soft-bottom communities, but were thought to have become extinct in the Late Ordovician. The unique holotype specimen of Naraoia bertiensis n. sp. comes from a Konservat–Lagerstätte deposit renowned for its eurypterid fauna (the Williamsville Member of the Bertie Formation). Naraoia bertiensis lacks thoracic segments and is morphologically similar to Naraoia compacta from the Middle Cambrian Burgess Shale, save for the presence of a long ventral cephalic doublure and a subtly pointed posterior shield. To examine the phylogenetic relationships of the new naraoiid, we coded characters of the holotype specimen and of nine previously described nektaspids. The results confirm a sister taxon relationship between Naraoia compacta and Naraoia bertiensis and the monophyly of nektaspid forms lacking thoracic segments (family Naraoiidae). This latter group may have arisen from an ancestral segment-bearing form through heterochronic loss of thoracic segments early in the Cambrian. The disjunct occurrence of a naraoiid nektaspid in the Late Silurian resembles the reappearance of other “Lazarus taxa” that were thought to have been eliminated during mass extinction events. The naraoiid lineage survived the Late Ordovician biotic crisis, but in this case the “Lazarus effect” seems likely to be taphonomic in origin.


1970 ◽  
Vol 27 (6) ◽  
pp. 1109-1114 ◽  
Author(s):  
C. G. Gruchy

Occella impi, a new species of sea poacher, is described from a single specimen captured in the Queen Charlotte Islands, British Columbia. Occella impi differs from other species of Occella in having spinous plates on the breast, the anus nearer the anal fin, and fewer anal rays; also, the numbers of bony body plates are distinctive. A key to the known species of Occella, based primarily on the numbers of bony body plates, is included. The size of the maxillary barbel and number of infralateral plates are shown to be characteristic of the genera Occella and Stellerina.


1988 ◽  
Vol 66 (7) ◽  
pp. 1502-1505 ◽  
Author(s):  
Jane P. M. Richardson ◽  
Martin L. Adamson

A new species of kathlaniid nematode, Megalobatrachonema waldeni, from the intestine of the northwestern salamander, Ambystoma gracile, in British Columbia is described. The new species is placed in the subgenus Megalobatrachonema (Chabaudgolvania) as it lacks valves in the oesophageal bulb. Megalobatrachonema waldeni differs from the two other members of this subgenus, M. elongatum (Baird, 1958) and M. terdentatum (Linstow, 1890), in having large cervical alae and distinctly separate lips, and in lacking hypodermal lip peduncles and a pseudosucker. Megalobatrachonema waldeni has simpler onchia, smaller spicules, and a more prominent swelling at the base of the oesophageal corpus than M. elongatum, and differs from M. terdentatum by its distinct corpus swelling, more anterior excretory pore, fewer caudal papillae, and longer tail.


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