Trachyplax arctica, a new multiplated problematic fossil from the Lower Cambrian of North Greenland

• Autorzy: Larsson C M , Peel J.S. , Hogstrom A.E.S.
• Języki publikacji: EN

Abstrakty

EN

A new scleritome−bearing organism with eight sclerite types, Trachyplax arctica gen. et sp. nov., is described from the lower Cambrian Paralledal Formation of North Greenland. The originally calcareous sclerites are now silicified; no microstructures are preserved. The dominant sclerite type (A; maximum dimension 19.3 mm) is bilaterally symmetrical, strongly arched, with an oval shield showing co−marginal growth lines and a projecting rostrum with prominent radial ornamentation. A similar sclerite morphology can be identified in Silurian–Carboniferous multiplacophoran molluscs but the remaining sclerite types, which also display a combination of concentric and radial ornamentation, find no clear equivalents. Two models for scleritome reconstruction are presented, based on the relative abundance of the sclerites, but neither promotes a satisfactory assignment to a higher taxon. Despite the morphological dissimilarities, possibly reflecting the age discrepancy, reference to the Multiplacophora is most attractive and entails a substantial extension of the known geological range of that group.

Słowa kluczowe

EN

Trachyplax arctica; fossil; paleontology; Lower Cambrian; Cambrian; North Greenland; Greenland; Trachyplax; Problematica; sclerite; scleritome; Multiplacophora; Paralledal Formation

• Wydawca: -
• Czasopismo: Acta Palaeontologica Polonica
• Rocznik: 2009
• Tom: 54
• Numer: 3
• Opis fizyczny: p.513-523,fig.,ref.

Twórcy

autor

Larsson C M

• Uppsala University, Villavagen 16, SE-752-36 Uppsala, Sweden

autor

Peel J.S.

autor

Hogstrom A.E.S.

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