Please use this identifier to cite or link to this item:
|Scopus||Web of Science®||Altmetric|
|Title:||An exceptional record of Cambrian trilobite moulting behaviour preserved in the Emu Bay Shale, South Australia|
|Citation:||Lethaia, 2018; 51(4):473-492|
|Harriet B. Drage, James D. Holmes, Diego C. García-Bellido and Allison C. Daley|
|Abstract:||Trilobites dominate the Emu Bay Shale (EBS) assemblage (Cambrian Series 2, Stage 4, South Australia) in terms of numbers, with Estaingia bilobata Pocock 1964 being extremely abundant, and the larger Redlichia takooensis Lu 1950, being common. Many specimens within the EBS represent complete moulted exoskeletons, which is unusual for Cambrian fossil deposits. The abundance of complete moults provides an excellent record that has allowed the recognition of various recurrent moult configurations for both species, enabling the inference of movement sequences required to produce such arrangements. Moult configurations of E. bilobata are characterized by slight displacement of the joined rostral plate and librigenae, often accompanied by detachment of the cranidium, suggesting ecdysis was achieved by anterior withdrawal via opening of the cephalic sutures. Moulting in R. takooensis often followed the same method, but configurations show greater displacement of cephalic sclerites, suggesting more vigorous movement by the animal during moulting. Both species also show rare examples of Salter's configuration, with the entire cephalon anteriorly inverted, and several other unusual configurations. These results indicate that moulting in trilobites was a more variable process than originally thought. In contrast, other Cambrian Konservat‐Lagerstätten with an abundance of trilobites (e.g. Wheeler Shale, USA, and Mount Stephen Trilobite Beds, Canada) show larger numbers of ‘axial shields’ and isolated sclerites, often interpreted as disarticulated exuviae. This points to a higher level of disturbance from factors, such as animal activity, depositional processes or water movement, compared to that of the EBS, where quiescent conditions and intermittent seafloor anoxia contributed to an unparalleled trilobite moulting record.|
|Keywords:||Burgess Shale; Cambrian; ecdysis, Emu Bay Shale; Lagerstätten; moult configuration; trilobite|
|Rights:||© 2018 Lethaia Foundation. Published by John Wiley & Sons Ltd|
|Appears in Collections:||Geology & Geophysics publications|
Files in This Item:
There are no files associated with this item.
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.