Reproductive system of the insular yellow crab Johngarthia lagostoma (H. Milne Edwards, 1837) (Brachyura: Gecarcinidae): from production to the storage of seminal fluid

Abstract This study describes the reproductive systems of male and female Johngarthia lagostoma , a land crab endemic to South Atlantic oceanic islands, focusing on spermatozoa production and storage. Specimens from Trindade Island (Brazil) were analysed for anatomy, histology, and histochemistry. The male system includes a pair of tubular testes showing different stages of spermatogenesis and spermiogenesis, leading to mature spermatozoa. These move to the anterior vas deferens (AVD), which has proximal and distal portions, the latter containing coenospermic spermatophores surrounded by secretion type I, reactive to proteins and acidic and neutral polysaccharides. The median (MVD) and posterior (PVD) vas deferens produce type II (strongly protein-reactive) and type III (weakly protein-reactive) secretions. Accessory glands between the MVD and PVD produce the same secretions plus a secretion type IV, reactive to neutral polysaccharides. These mix with the spermatophores and other vas deferens secretions, increasing the PVD’s secretion volume, crucial for the initial release of spermatophores into the seminal receptacle. The female reproductive system features voluminous seminal receptacles connected to the ovary, comprising mesodermal and ectodermal regions classified as ventral-type connection. Plugs and sperm packets are absent, with the seminal receptacles filled with free spermatozoa, suggesting dehiscence occurs shortly after sperm transfer. The influence of male and female secretions on this process is suggested, alongside their roles in sperm maintenance and fertilization facilitation.