Please use this identifier to cite or link to this item: https://hdl.handle.net/1959.11/30295
Title: The trilobite Redlichia from the lower Cambrian Emu Bay Shale Konservat-Lagerstätte of South Australia: systematics, ontogeny and soft-part anatomy
Contributor(s): Holmes, James D (author); Paterson, John R  (author)orcid ; García-Bellido, Diego C (author)
Publication Date: 2020-06
DOI: 10.1080/14772019.2019.1605411
Handle Link: https://hdl.handle.net/1959.11/30295
Abstract: The trilobite Redlichia Cossmann, 1902 is an abundant element of the lower Cambrian (Series 2, Stage 4) Emu Bay Shale (EBS) Konservat-Lagerstätte on Kangaroo Island, South Australia. Well-preserved, fully articulated specimens from this deposit are known to reach lengths of up to 25 cm, representing one of the largest known Cambrian trilobites. Until now, all Redlichia specimens from the EBS have been referred to Redlichia takooensis Lu, 1950, a species originally described from South China. Previous work recognized considerable differences in exoskeletal morphology among specimens of varying sizes, which was attributed to ontogeny. However, close examination of a large collection of recently acquired specimens shows that this variation actually represents two distinct morphs, interpreted here as separate species: R. takooensis, and a large, new species, Redlichia rex sp. nov. An analysis of morphological variation in holaspides ('adults') of the more common R. takooensis reveals considerable ontogenetic change occurred even during this later phase of growth. Some specimens of both Redlichia species from the EBS also exhibit exceptionally preserved soft-part anatomy, particularly the antennae and biramous appendages. Here, appendages (antenniform and biramous) and digestive structures are described, and biramous appendage reconstructions of R. rex sp. nov. are presented, which show a striking resemblance to some early Cambrian trilobites from South China. In particular, R. rex has a tripartite exopodite, as well as a dorsoventrally deep protopodite with gnathobasic spines used to shred or crush food items. Based on recent phylogenetic analyses, it is possible that an exopodite with tripartite subdivisions represents the plesiomorphic condition for Artiopoda (trilobites and kin). The digestive system of R. takooensis exhibits a series of paired digestive glands in the cephalon and anterior thorax, similar to those described for a number of other Cambrian and Ordovician trilobites.
Publication Type: Journal Article
Grant Details: ARC/LP0774959
ARC/FT120100770
ARC/FT130101329
Source of Publication: Journal of Systematic Palaeontology, 18(4), p. 295-334
Publisher: Taylor & Francis
Place of Publication: United Kingdom
ISSN: 1478-0941
1477-2019
0968-0462
Fields of Research (FoR) 2008: 040308 Palaeontology (incl. Palynology)
060301 Animal Systematics and Taxonomy
Fields of Research (FoR) 2020: 370506 Palaeontology (incl. palynology)
310401 Animal systematics and taxonomy
Socio-Economic Objective (SEO) 2008: 970104 Expanding Knowledge in the Earth Sciences
970106 Expanding Knowledge in the Biological Sciences
Socio-Economic Objective (SEO) 2020: 280107 Expanding knowledge in the earth sciences
280102 Expanding knowledge in the biological sciences
Peer Reviewed: Yes
HERDC Category Description: C1 Refereed Article in a Scholarly Journal
Appears in Collections:Journal Article
School of Environmental and Rural Science

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