Revision of the late Cambrian trilobite genus Archikainella

Author(s):  
Xuejian Zhu ◽  
Shanchi Peng ◽  
Tatyana V. Pegel ◽  
Jingxun Zuo
2020 ◽  
Vol 94 (5) ◽  
pp. 867-880
Author(s):  
Shelly J. Wernette ◽  
Nigel C. Hughes ◽  
Paul M. Myrow ◽  
Apsorn Sardsud

AbstractThe Ao Mo Lae Formation of the Tarutao Group crops out on Thailand's Tarutao Island and contains a diverse assemblage of late Furongian trilobite taxa, including several endemic forms. This study presents a new genus and species, Satunarcus molaensis, discovered at two locations on the island. A cladistic analysis of the kaolishaniid subfamily Mansuyiinae in light of Satunarcus and similar genera known from across upper Cambrian equatorial Gondwanan rocks suggests that the subfamily is polyphyletic in its current definition, and thus is not a natural group. Separating Mansuyia Sun, 1924 from the other taxa conventionally placed in Mansuyiinae permits recognition of a previously unrecognized monophyletic subfamily Ceronocarinae new subfamily. As established herein, this kaolishaniid subfamily contains Satunarcus n. gen. and all genera previously recognized as Mansuyiinae. with the exception of Mansuyia itself. Ceronocarinae n. subfam. occur in middle Jiangshanian to middle Cambrian Stage 10 sedimentary rocks from Australia, South China, North China, and Sibumasu, with most genera endemic to Australia.UUID: http://zoobank.org/618c5136-73f0-4912-a7d3-e56559d2a76c


2005 ◽  
Vol 79 (1) ◽  
pp. 72-88 ◽  
Author(s):  
STEPHEN R. WESTROP ◽  
ALLISON R. PALMER ◽  
ANTHONY RUNKEL

1986 ◽  
Vol 23 (3) ◽  
pp. 300-307 ◽  
Author(s):  
Rolf Ludvigsen ◽  
Stephen R. Westrop

Idiomesus Raymond, 1924 has been considered to be a Late Cambrian member of the blind family Shumardiidae on the basis of its small size, absence of eyes, effacement, and marginal sutures. However, evaluation of new material, including previously undescribed species, demonstrates that Idiomesus is a member of the ptychaspidid subfamily Ptychaspidinae. The genus now includes both sighted and blind species, as well as furrowed and effaced species with both marginal and opisthoparian sutures. New species are Idiomesus granti, I. greggi, and I. ultimus.


2002 ◽  
Vol 139 (3) ◽  
pp. 281-290 ◽  
Author(s):  
A. W. A. RUSHTON ◽  
L. R. M. COCKS ◽  
R. A. FORTEY

A new Late Cambrian trilobite–brachiopod fauna from the Kurchavinskaya Formation, Severnaya Zemlya, northern Siberia, allows correlation of the Ketyi Horizon of the NW Siberian succession with the praecursor Zone of the Baltic olenid zonation. The presence on Severnaya Zemlya of the typically Siberian trilobite Kujandaspis ketiensis indicates that even if Severnaya Zemlya lay on a separate plate, whether Kara or Arctida as postulated by other authors, then it was still probably not far from Siberia. However, the associated brachiopods are partly endemic to Severnaya Zemlya, thus giving some support to the independent palaeomagnetic evidence for their origin on a plate separate from Siberia.


2000 ◽  
Vol 137 (5) ◽  
pp. 485-494 ◽  
Author(s):  
E. LANDING ◽  
S. A. BOWRING ◽  
K. L. DAVIDEK ◽  
A. W. A. RUSHTON ◽  
R. A. FORTEY ◽  
...  

Two thin volcaniclastic sandstone beds in the Bryn-llin-fawr road section in North Wales overlie an apparent sequence boundary within the uppermost Cambrian Acerocare Zone and are overlain by lowest Ordovician (lower Tremadoc) Rhabdinopora faunas. U–Pb geochronology of zircons from these sandstones yields a maximum Cambrian–Ordovician boundary age of 489±0.6 Ma. This age indicates both that the Tremadoc Series (lowest Ordovician) may be shorter in duration than was previously thought and that the duration of the Middle and Late Cambrian (c. 22 Ma) was much less than that of the Early Cambrian (c. 33 Ma). Cambrian trilobite zones locally had an average duration as short as 1 Ma.


1995 ◽  
Vol 86 (4) ◽  
pp. 247-256 ◽  
Author(s):  
Adrian W. A. Rushton ◽  
Nigel C. Hughes

ABSTRACTThe restoration of deformed specimens of the trilobite Conocoryphe abdita Salter from the late Cambrian of Wales allows a re-evaluation of their systematics, synonymy with other species described from Siberia and Iran, and assignment to the idahoiid genus Maladioidella. Maladioidella abdita is from the Parabolina spinulosa Biozone, and most species similar to it occur in equivalent strata near the lower part of the Iverian Stage. Widespread homeomorphy in primitive libristomates is documented and presents difficulties for assessing relationships within Maladioidella and among related taxa. Both the genus as a whole and the species M. abdita show a widespread peri-Gondwanan distribution that crosses a range of latitudes and lithofacies and, to a limited extent, oceanic basins. No morphological features were discerned that might account for its unusual dispersal ability.


2002 ◽  
Vol 76 (4) ◽  
pp. 709-717 ◽  
Author(s):  
Nigel C. Hughes ◽  
Peng Shanchi ◽  
Luo Huilin

Faunal data provide critical constraints upon tectonic models, particularly in such areas of extreme structural complexity as the region adjacent to the eastern syntaxis of the Himalaya. Trilobites reported to have been collected from the Yunling collage at Yinchangou, northwestern Yunnan, are here assigned toKunmingaspis yunnanensisChang, 1964, and the concept of the genusKunmingaspisis reconsidered. Although there is debate about to the paleogeographic affinities of the Yunling collage, the apparent presence of this species supports previous arguments for faunal links between the Yangtze platform and the Himalayan margin during Early and Middle Cambrian time. A significant tectonic event of Late Cambrian/Early Ordovician age present in the western central Himalayan margin suggests that the Lhasa block collided with India at that time, but the northward extent of that block remains unclear. The recently discovered Late Cambrian trilobite fauna of Bhutan may hold the key to establishing faunal relationships between the Tethyan Himalaya, Sibumasu, and the Yangtze platform during this interval. No Cambrian sedimentary rocks are yet known from the Lhasa or Qiangtang blocks of Tibet and so there is no direct evidence for the existence of Cimmeria during the Cambrian Period.


1994 ◽  
Vol 68 (3) ◽  
pp. 492-517 ◽  
Author(s):  
Conrad C. Labandeira ◽  
Nigel C. Hughes

It has been proposed previously that the northern Mississippi Valley Sunwaptan trilobite genus Dikelocephalus comprises 26 species. Morphometric analyses demonstrate that many of the criteria that had been used to define species of Dikelocephalus are invalid and additional analysis of biostratigraphically and biogeographically constrained collections is necessary before the taxonomic status of Dikelocephalus can be fully resolved. Our results indicate that infrageneric morphological variation in Dikelocephalus is continuous and lacks gaps that could be the basis for establishing multiple species. Many of the characters shown to be taxonomically insignificant in Dikelocephalus are also widely used in the definition of other trilobite taxa. This suggests that the species-level taxonomy of many trilobites may be substantially oversplit. Recognition of widespread oversplitting will have important consequences for biostratigraphic zonations, paleogeographic distributions, and estimates of taxonomic diversity.


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