New Cambrian lobopods and chaetognaths of the Siberian Platform

Demidenko, Yu. E.

doi:10.1134/s0031030106030026

Cited by 9 publications

(13 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Phosphorus or other elements except carbon and iron are not enriched in either Hallucigenia or Onychodictyon sclerites studied herein. However, the structure, pore sizes, and overall dimensions in sclerites from articulated individuals of Onychodictyon ferox are identical with those of disarticulated phosphatic sclerites described as Onychomicrodictyon spiniferum from the Toyonian of Siberia (Demidenko 2006) and an undetermined sclerite thought to combine features of Microdictyon and Hallucigenia from Greenland (Bengtson 1991 A similar difference exists in the preservation of netlike sclerites of the small shelly material and articulated specimens of Microdictyon from Burgess Shale-type fossil Lagerstätten such as Chengjiang or Kaili. Dispersed sclerites of Microdictyon and the related genus Quadratapora are always preserved as phosphatic net-like three-dimensional structures, whereas those in articulated individuals of Microdictyon from the Chengjiang fossil Lagerstätte never showed any phosphatic remains.…”

Section: The Structure and Preservation Of Scleritesmentioning

confidence: 91%

A new species of Hallucigenia from the Cambrian Stage 4 Wulongqing Formation of Yunnan (South China) and the structure of sclerites in lobopodians

Keupp¹,

Liu²,

Steiner³

et al. 2012

Bull. Geosci.

View full text Add to dashboard Cite

Hallucigenia hongmeia sp. nov. and Hallucigenia sparsa are described from the Cambrian Stage 4 Guanshan fossil Lagerstätte of Wulongqing Formation from Guangwei in Kunming district, Yunnan Province, South China. The paired trunk sclerites of lobopodians reveal a general net-like microstructure, which is documented for the genera Hallucigenia, Onychodictyon and Microdictyon. This microstructure is comparable to a similar microstructure in paired trunk sclerites of the palaeoscolecidan sensu lato Cricocosmia and Tabelliscolex. The net-like trunk sclerites of lobopodians are interpreted as having carried numerous sensory or secretory papillae. Lobopodian sclerites such as Hallucigenia, Onychodictyon and Microdictyon and the palaeoscolecidans s.l. Cricocosmia and Tabellicsolex were primarily composed of tanned organic structures. Duplicates of trunk sclerites in Microdictyon and Cricocosmia point to a moulting of the external cuticle. The structure and form of prominent claws in Hallucigenia hongmeia sp. nov. are interpreted as indicative of an adapted lifestyle in the epibenthos

show abstract

Section: The Structure and Preservation Of Scleritesmentioning

confidence: 91%

A new species of Hallucigenia from the Cambrian Stage 4 Wulongqing Formation of Yunnan (South China) and the structure of sclerites in lobopodians

Keupp¹,

Liu²,

Steiner³

et al. 2012

Bull. Geosci.

View full text Add to dashboard Cite

show abstract

“…Node labels show the posterior probability for each clade. Principal references for the data on protoconodonts are obtained from Bengtson (); Demidenko (); Doguzhaeva et al . (); Dong & Bergström (); Ethington (); Kouchinsky et al .…”

Section: Ankalodous Sericus Sp Nov Figures mentioning

confidence: 99%

Multi‐jawed chaetognaths from the Chengjiang Lagerstätte (Cambrian, Series 2, Stage 3) of Yunnan, China

et al. 2017

View full text Add to dashboard Cite

Chaetognaths (arrow-worms) are enigmatic in terms of their phylogenetic position, while the existence of Protosagitta spinosa from the Chengjiang Lagerst€ atte suggests minimal change in their unique bodyplan since at least the early Cambrian. Apart from rare (and sometimes controversial) soft-bodied remains, the fossil record of chaetognaths is otherwise almost entirely dependent on early Palaeozoic phosphatic microfossils, some of which are placed amongst so-called protoconodonts. Fused spine clusters are strikingly similar to the cephalic grasping apparatus of extant forms and are assumed to have had a comparable configuration. Here we report a new chaetognath, Ankalodous sericus gen. et sp. nov., coeval with Protosagitta but with a complex feeding apparatus consisting of multiple bundles of recurved spines whose principal function appears to have been grasping. Like all other chaetognaths a predatory mode of life is likely, but its position relative to the sediment-water interface is less certain. Reduction of the feeding apparatus, from the multi-jawed arrangement of A. sericus to the grasping spines and associated smaller teeth seen in other chaetognaths, was probably a subsequent development and conceivably was linked with a shift to a pelagic mode of life. We also report a new specimen of Protosagitta. This confirms earlier observations but it possesses hitherto unrecognized features, including a cephalic tentacle and fin rays.

show abstract

“…The Cambrian net-like isolated plates, including Microdictyon, are usually described under the family Eoconchariidae (Chen et al, 1995;Demidenko, 2006;Zhang and Aldridge, 2007;Topper et al, 2009), which consists of three genera: Microdictyon Bengtson, Matthews and Missarzhevsky, 1981, Quadratapora Hao and Shu, 1987and Fusuconcharium Hao and Shu, 1987 Fusuconcharium exhibits a disorderly hexagonal hole arrangement with spine-like or rounded nodes (Zhang and Aldridge, 2007). Demidenko (2006) Bengtson (1991) are identical with Onychodictyon ferox . Therefore, Onychomicrodictyon was considered to be a junior synonym of Onychodictyon (Steiner et al, 2012;Topper et al, 2013).…”

Section: Taxonomy Of Isolated Eoconchariid Platesmentioning

confidence: 99%

“…Phylum Lobopodia Snodgrass, 1938 Class Xenusia Dzik and Krumbiegel, 1989 Order Archonychophora Hou and Bergstrӧm, 1995 Family Eoconchariidae Hao and Shu, 1987 Genus Microdictyon robisoni Bengtson, Matthews and Missarzhevsky, 1986; M. chinense Hao and Shu, 1987; M. sphaeroides Hinz, 1987;M. sinicum Chen, Hou and Lu, 1989; depressum Bengtson in Bengtson et al 1990; M. fuchengense Li and Zhu, 2001; M. Demidenko, 2006 was erected based on 2 broken plates that display a characteristic extended edge (Demidenko, 2006). This lateral extension is somewhat similar to the edge of M. rhomboidale, but we consider this subtle variation of the plate edge as insufficient evidence to erect a new species and based on node morphology we suggest that these specimens most likely represent interspecific variants of M. rhomboidale.…”

Section: Systematic Paleontologymentioning

confidence: 99%

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

Pan

Topper²,

Skovsted³

et al. 2017

J. Paleontol.

View full text Add to dashboard Cite

Disarticulated 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.

show abstract

New Cambrian lobopods and chaetognaths of the Siberian Platform

Cited by 9 publications

References 6 publications

A new species of Hallucigenia from the Cambrian Stage 4 Wulongqing Formation of Yunnan (South China) and the structure of sclerites in lobopodians

A new species of Hallucigenia from the Cambrian Stage 4 Wulongqing Formation of Yunnan (South China) and the structure of sclerites in lobopodians

Multi‐jawed chaetognaths from the Chengjiang Lagerstätte (Cambrian, Series 2, Stage 3) of Yunnan, China

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

Contact Info

Product

Resources

About