The venom apparatus of the scorpion fish Notesthes Robusta

Abstract

The venom apparatus of Notesthes robusta, an Australian scorpaenid fish which has been responsible for numerous severe injuries, consists of the 15 spines of the dorsal fin, the three spines of the anal fin and the single spine of each ventral fin together with the paired venom glands carried in grooves in each of these spines. Each venom gland is composed of a double row of large gland cells derived from a central core of epidermal cells in the interior of the gland, and each gland cell is surrounded and supported by epidermal cells. Proteinaceous venom granules are elaborated in cytoplasmic vacuoles in the gland cells. The cytoplasm subsequently disintegrates and the granules remain in fluid-filled sacs which are pushed to the periphery of the gland. Envenomation occurs when a spine enters the flesh. The integumentary sheath surrounding each spine is pushed proximally and only the spine and associated venom glands enter the puncture. The distal end of each gland tears and venom is injected. Partial regeneration of venom glands occurs within 6 days. A bridge of epidermal cells connecting a regenerating venom gland with the epidermis of its surrounding integumentary sheath was demonstrated.