A new species of Cyrtograptus (Graptoloidea) from the Llandovery of Västergötland (Sweden)
2011 (English)In: The 2nd Wiman Meeting: Carl Wiman's Legacy: 100 years of Swedish Palaeontology, Uppsala, 2011, 2-2 p.Conference paper (Refereed)
A new species of the genus Cyrtograptus from the late Llandovery of southern Sweden (Västergötland) is presented. The new species has been found near the top of Kinnekulle (Högkullen) in the Retiolites Shales, which are part of the lapworthi zone (late Telychian). Although it resembles the coeval C. lapworthi in appearance, a detailed comparison of the type material of C. lapworthi revealed distinct differences: the new species is more openly coiled in the proximal part, has a larger Two Thecae Repeat Distance (2TRD), and, most significantly, bears a second order cladium. Second order cladia are unknown from C. lapworthi. The new species is also compared with other species of Cyrtograptus that are characterized by second order cladia, such as the cotemporaneous C. laqueus and the slightly younger C. insectus (insectus zone; latest Telychian). However, C. laqueus differs from the new species in having a lower number of thecae separating the cladia, and also by the appearance of its proximal part, which forms a loop by crossing its own main stipe. C. insectus differs by having wider spaced cladia and a stronger coiled proximal part. Furthermore, the need of a redefinition of C. lapworthi is highlighted, due to the large morphological variations within this species.
Place, publisher, year, edition, pages
Uppsala, 2011. 2-2 p.
Other Earth and Related Environmental Sciences
Research subject Earth Science with specialization in Historical Geology and Palaeontology
IdentifiersURN: urn:nbn:se:uu:diva-165206OAI: oai:DiVA.org:uu-165206DiVA: diva2:472453
The 2nd Wiman Meeting, EBC, Uppsala,17 - 18 November 2011