Precocious sexual dimorphism and the Lilliput effect in Neo‐Tethyan Ostracoda (Crustacea) through the Permian–Triassic boundary |
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| Authors: | Marie‐Béatrice Forel Sylvie Crasquin Anisong Chitnarin Lucia Angiolini Maurizio Gaetani |
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| Affiliation: | 1. State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China;2. CR2P CNRS – UPMC – MNHN, Sorbonne Universités, Paris Cedex 05, France;3. School of Geotechnology, Institute of Engineering, Suranaree University of Technology, Mueang District, Nakhon Ratchasima Province, Thailand;4. Dipartimento di Scienze della Terra, Università di Milano, Milano, Italy |
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| Abstract: | The Elikah River section spanning the Lopingian (Late Permian) to the Griesbachian (Early Triassic) time interval in the Central Alborz Mountains (north Iran) was sampled for ostracod analysis. We report 79 species distributed among 38 genera. Four new species are described: Acratia? pervagata Forel sp. nov., Microcheilinella alborzella Forel sp. nov., Basslerella superarella Crasquin sp. nov. and Cavellina nesenensis Crasquin sp. nov. The ontogeny of 13 species is described and sexual dimorphism in the genus Microcheilinella is here undoubtedly recognized for the first time. Six species show precocious sexual dimorphism of their carapace as early as A‐5 juvenile. The Lilliput effect is for the first time recorded and quantified for two species. Rare long‐time span Palaeocopida species, known throughout the entire Permian, document relatively long‐term evolution, including the size and growth rate modifications associated with the earlier appearance of carapace sexual dimorphism through time. These patterns might be related to the Guadalupian–Lopingian events and/or to climatic modifications occurring during the Permian interval. |
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| Keywords: | Ostracods north Iran Permian– Triassic ontogeny precocious sexual dimorphism Lilliput effect |
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