Size, sex ratio, and morphological features of Harris crab, Rhithropanopeus harrisii (Gould, 1841) (Brachyura: Panopeidae), Taman Bay, 2021

The article presents the features of sex and size composition, morphology of the crabs Rhithropanopeus harrisii from Taman Bay collected in July 2021. In the sample, males outnumbered females fourfold; juveniles were not encountered. Sizes: the carapace width of males was 7.3–21.4 mm (on average 14.4±2.5 mm), the carapace length was 5.5–15.9 mm (on average 11.0±1.8 mm); the carapace width of females was 8.6– 15.9 mm (on average 10.8±1.7 mm), the carapace length was 6.7–12.1 mm (on average 8.3±1.3 mm). Among males, individuals with a carapace width of 13–15 mm (46 % share) and a carapace length of 10–11 mm (48 %) were dominant, while among females, those with a carapace width of 10–11 mm (45 % share) and a carapace length of 7–9 mm (77 % share) were dominant. A morphometric analysis of 18 plastic characters of six elements of the crab's exoskeleton revealed a number of features of sexual dimorphism in the species of the Gulf: the sizes of most plastic characters of carapace, abdomen, merus of pereiopods 2 and 3 and of the right and left claws were 12–49 % smaller in females than in males (the exception was the fourth abdominal segment, which was 45 % wider in females). Similarities for crabs of both sexes were also noted: their right claw was significantly larger than the left claw, reflecting the functional specialization of the claws. A comparative analysis with morphometric data for R. harrisii of that Bay from a decade ago suggested a relatively stable dimensional structure and exoskeleton morphology in Harris crab specimens from Taman Bay settlements.

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