Field survey data: spatial distribution and sex ratio of Cyrtograpsus angulatus and C. affinis, Playa Cangrejales, Argentina (2019–2020)

This dataset contains individual-level field survey records of two sympatric intertidal crab species, Cyrtograpsus angulatus Dana, 1851 and Cyrtograpsus affinis (Dana, 1851) (Brachyura: Varunidae), collected monthly (December 2019, January 2020, February 2020) at Playa Cangrejales, within the Magagna Complex Area Municipal Turística Protegida, Rawson, Chubut, Argentina (43°23′56″ S, 65°03′07″ W). Sampling followed two parallel transects (C-I and C-II) perpendicular to the shoreline, spanning the upper, middle, and lower mesolittoral zones, using 0.25-m² quadrats placed at 5-m intervals. The dataset underlies the analyses reported in: Onorato, M.A., Cochia, P.D., Oviedo, J.G.L. Spatial distribution and seasonal sex-ratio dynamics of grapsid crabs Cyrtograpsus angulatus and Cyrtograpsus affinis (Brachyura: Varunidae) in the intertidal zone. [journal / DOI to be added upon acceptance] It is a companion dataset to the same field campaign reported in: Onorato, M.A., Cochia, P.D., Oviedo, J.G.L. (2024). Size distribution and proportion of stages of Cyrtograpsus species in Playa Cangrejales, Argentina. Austral Ecology, 49, e13579. https://doi.org/10.1111/aec.13579 Total individuals recorded: 1,099 (610 C. affinis, 489 C. angulatus), matching the total reported in Onorato et al. (2024).