scholarly journals First report of brachiopods with soft parts from the Lower Cambrian Latham Shale (Series 2, Stage 4), California

2020 ◽  
Vol 65 (18) ◽  
pp. 1543-1546
Author(s):  
Yue Liang ◽  
Lars E. Holmer ◽  
Yazhou Hu ◽  
Zhifei Zhang
Keyword(s):  
Lower Cambrian ◽  
First Report ◽  
Stage 4

scholarly journals Caught in the act: priapulid burrowers in early Cambrian substrates

2019 ◽  
Vol 286 (1894) ◽  
pp. 20182505 ◽  
Author(s):  
Giannis Kesidis ◽  
Ben J. Slater ◽  
Sören Jensen ◽  
Graham E. Budd
Keyword(s):  
Comparative Analysis ◽  
Lower Cambrian ◽  
Trace Fossil ◽  
Considerable Importance ◽  
Cambrian Explosion ◽  
Early Cambrian ◽  
Southern Sweden ◽  
Stage 4 ◽  
Organic Remains

The fossilized traces of burrowing worms have taken on a considerable importance in studies of the Cambrian explosion, partly because of their use in defining the base of the Cambrian. Foremost among these are the treptichnids, a group of relatively large open probing burrows that have sometimes been assigned to the activities of priapulid scalidophoran worms. Nevertheless, most Cambrian burrows have an uncertain progenitor. Here we report a suite of exceptionally preserved trace and body fossils from sandstones of the lower Cambrian (Stage 4) File Haidar Formation of southern Sweden that can unequivocally be assigned to a scalidophoran producer. We further present the first burrow casts produced via actualistic experiments on living priapulids, and demonstrate the remarkable morphological parallels between these modern and Cambrian fossil equivalents. In addition, co-occurrence of scalidophoran-derived cuticular remains permits a unique synthesis of evidence from trace fossil, body and organic remains. Comparative analysis of these exceptionally preserved fossils supports a scalidophoran producer for treptichnids and by extension suggests a latest Ediacaran origin of the ecdysozoan clade.

scholarly journals First report on Guanshan Biota (Cambrian Stage 4) at the stratotype area of Wulongqing Formation in Malong County, Eastern Yunnan, China

2019 ◽  
Vol 10 (4) ◽  
pp. 1459-1476 ◽  
Author(s):  
Feiyang Chen ◽  
Zhifei Zhang ◽  
Marissa J. Betts ◽  
Zhiliang Zhang ◽  
Fan Liu
Keyword(s):  
First Report ◽  
Stage 4 ◽  
Guanshan Biota

Ontogeny, functional morphology, and comparative morphology of lower (Stage 4) and basal middle (Stage 5) Cambrian gogiids, Guizhou Province, China

2012 ◽  
Vol 86 (4) ◽  
pp. 569-583 ◽  
Author(s):  
Ronald L. Parsley
Keyword(s):  
Lower Cambrian ◽  
Comparative Morphology ◽  
Juvenile Stage ◽  
Guizhou Province ◽  
Mature Stage ◽  
Middle Cambrian ◽  
Fine Grained ◽  
Lower Stage ◽  
Stage 4 ◽  
In Series

Three gogiid eocrinoids, numbering in the thousands of specimens, are well known from the lower Cambrian (Stage 4) Balang Formation (Guizhoueocrinus yui) and basal middle Cambrian (Stage 5) Kaili Formation (Kaili Biota) (Sinoeocrinus lui and Globoeocrinus globulus) that resided on the Yangtze-South China Plate (modern Guizhou Province, China). In each species a complete ontogenetic sequence, using thecal height (TH) as a scale, juvenile stage (early, middle, and late substages), mature stage (early, middle, and late substages), and a gerontic stage can be identified. Sutural pores appeared in an orderly sequence; below the ambulacrals, above the stalk and generally over the theca, in that order. In younger species their emplacement and growth was commonly precocious relative to G. yui. Also, their shape ranges from circular to oval to triangular in a single growth sequence, after the establishment of the 2-1-2 pattern; brachioles were added in series of five and were also precocious in time of occurrence in younger species. Thecae in younger species tend to retain juvenile aspects relative to G. yui. All of these species lived in outer shelf settings in fine-grained, organic-rich siliciclastics.

scholarly journals Occurrence ofMicrodictyonfrom the lower Cambrian Xinji Formation along the southern margin of the North China Platform

2017 ◽  
Vol 92 (1) ◽  
pp. 59-70 ◽  
Author(s):  
Bing Pan ◽  
Timothy P. Topper ◽  
Christian B. Skovsted ◽  
Lanyun Miao ◽  
Guoxiang Li
Keyword(s):  
Lower Cambrian ◽  
North China ◽  
Ontogenetic Variation ◽  
Early Cambrian ◽  
North China Platform ◽  
Middle Cambrian ◽  
The North ◽  
Formation Stage ◽  
Inadequate Knowledge ◽  
Stage 4

AbstractDisarticulated net-like plates of the lobopodMicrodictyonhad a near cosmopolitan distribution from the early to middle Cambrian but are yet to be documented from the North China Platform. Here we report isolated plates ofMicrodictyonfrom the lower Cambrian Xinji Formation (Stage 4, Series 2) of the North China Platform, extending the paleogeographic distribution ofMicrodictyonin the early Cambrian. The plates ofMicrodictyonfrom the Xinji Formation are similar to those of other species established on the basis of isolated plates but do bear some new characters, such as mushroom-shaped nodes with a single inclined platform-like apex and an upper surface that displays radial lines. However, the plates documented here are left under open nomenclature due to inadequate knowledge of intraspecific and ontogenetic variation and low specimen numbers. Through comparison of the node shapes of the isolated plates of differentMicrodictyonspecies, we consider that low mushroom-shaped nodes could be a primitive and conservative character ofMicrodictyonwhile tall mushroom-shaped nodes may be a derived character. Subtle differences in shape and number of node apices may also represent intraspecific or ontogenetic variation.

On Callavia (Trilobita) from the Cambrian Series 2 of Iberia with systematic status of the genus

2021 ◽  
pp. 1-15
Author(s):  
Luis Collantes ◽  
Sofia Pereira ◽  
Eduardo Mayoral ◽  
Eladio Liñán ◽  
Rodolfo Gozalo
Keyword(s):  
Lower Cambrian ◽  
Morphological Characters ◽  
Western Mediterranean ◽  
Middle Part ◽  
Junior Synonym ◽  
The West ◽  
West Gondwana ◽  
Stage 4 ◽  
New Material ◽  
New Diagnosis

Abstract Olenellid trilobites from the lower Cambrian of the Iberian Peninsula are very scarce and poorly studied, making them difficult to compare with defined species and to include in biostratigraphic and paleobiogeographic analyses. Based on newly collected specimens, we revise the species ‘Callavia? lotzei’ Richter and Richter, 1941 from the ‘Cumbres beds’ of Cumbres de San Bartolomé and the ‘Herrerías shale’ of Cañaveral de León, Sierra del Bujo, and Hinojales (Huelva, Spain), and ‘Paradoxides choffati’ Delgado, 1904 from the Vila Boim Formation of Elvas (Portugal). The new material indicates that Callavia? lotzei is a junior synonym of ‘P. choffati.’ The Iberian species are here assigned to Callavia Matthew, 1897, for which morphological characters are reassessed, offering a valuable opportunity to discuss characters previously misinterpreted for this genus. Traditionally assigned to the Olenelloidea Walcott, 1890, Callavia lacks some of the diagnostic characters of this superfamily and is here assigned to Judomioidea Repina, 1979. A new diagnosis for this genus is provided, and Sdzuyomia Lieberman, 2001 is considered to represent a junior synonym of Callavia. The genus Callavia is distributed across the western margin of Gondwana, from the western Mediterranean region (Iberia and Morocco) throughout all the Avalonia sectors (UK, eastern Newfoundland, and Massachusetts). Its presence in Iberia supports the faunal links between the West Gondwana domain and Avalonia during Cambrian Series 2. The Iberian records of Callavia choffati are assigned to the middle part of the regional Marianian Stage (uppermost Cambrian Stage 3 to the lowermost Cambrian Stage 4) and correlates with the Callavia Biozone of Avalonia (lower Branchian Series).

First report of acrotretoid brachiopod shell beds in the lower Cambrian (Stage 4) Guanshan Biota of eastern Yunnan, South China

2020 ◽  
Vol 95 (1) ◽  
pp. 40-55 ◽  
Author(s):  
Xiaolin Duan ◽  
Yue Liang ◽  
Lars E. Holmer ◽  
Zhifei Zhang
Keyword(s):  
South China ◽  
Lower Cambrian ◽  
Yunnan Province ◽  
First Record ◽  
Soft Substrate ◽  
Median Septum ◽  
Stage 4 ◽  
Shell Beds ◽  
Guanshan Biota ◽  
A New Species

AbstractBrachiopod shell accumulations are abundant and diverse in the lower Cambrian strata of Yunnan Province, South China, but most commonly they are composed of linguloid and acrotheloid brachiopods. Here, we describe the first record of shell beds with high-density accumulations of microscopic acrotretoid brachiopods (usually <2 mm in width) in the muddy deposits of the Wulongqing Formation (Guanshan Biota, Cambrian Stage 4) in the Wuding area of Yunnan Province. The acrotretoid shell beds from the Wulongqing Formation vary from thin mm-thick pavements to more well-developed beds, several centimeters thick. The occurrence of remarkably rich acrotretoid shell beds indicates that microscopic lingulates began to exert an important role in hardening and paving the soft-substrate seafloor during the early Cambrian evolution of Phanerozoic “mixgrounds.” The new Guanshan material is referred to a new species, Linnarssonia sapushanensis n. sp., which differs from other species of Linnarssonia mainly in having a well-developed internal pedicle tube, as well as a relatively longer dorsal median septum. The occurrence of Linnarssonia sapushanensis n. sp. in the Wulongqing Formation in eastern Yunnan extend the oldest record of the genus on the Yangtze Platform of South China back to at least Cambrian Stage 4.UUID: http://zoobank.org/3e0c3878-6ce2-4eed-87bf-e39647c310c4

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