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Durham University

Department of Earth Sciences


Publication details for Professor David Harper

Nielsen, M.L., Rasmussen, J.A. & Harper, D.A.T. (2017). Sexual dimorphism within the stem-group arthropod Isoxys volucris from the Sirius Passet Lagerstätte, North Greenland. Bulletin of the Geological Society of Denmark 65: 47-58.

Author(s) from Durham


Morphometric analyses carried out on 126 specimens of the early Cambrian (Cambrian Series 2, Stage 3) stem-group arthropod Isoxys volucris from North Greenland reveal a bimodal distribution, where Morphogroup A is characterised by a significantly wider doublure than Morphogroup B. The dimorphism is interpreted as intraspecific variation related to gender (sexual dimorphism), where the relative numbers of individuals within the two morphogroups are equal (ratio 1:1). The discovery of established sexual dimorphism in Isoxys may have implications for the taxonomic discrimination of other stemgroup arthropods within the morphologically diverse and disparate animals of the early Cambrian.