Southern Bottletail

Sepiadarium austrinum

Southern Bottletail squids are small and rounded cephalopods characterized by their kidney-shaped fins located on the rear third of their bodies. They can grow to a mantle length of three centimeters and a total length of four centimeters. Their coloration varies, appearing transparent, yellow, or orange, often with egg-shaped white leucophores. This species is primarily found in the southern Indo-Pacific region, typically inhabiting sandy environments in shallow, sheltered waters, with recorded depths of up to 65 meters, including a small population in the Spencer Gulf of southern Australia. These squids are active at night, burying themselves in the sand during the day and emerging to hunt after sunset. Their diet consists mainly of small fish and crustaceans, such as amphipods and benthic isopods. They exhibit interesting reproductive behaviors, where females can store sperm and mate with multiple males. Males transfer sperm packages to females without displaying elaborate courtship behaviors, and females may consume sperm as part of their reproductive process. They deposit clumps of eggs that are covered in sand and attached to seaweed or seagrass. Diving encounters with Southern Bottletail squids can be intriguing, as they often camouflage themselves in the sandy substrate. Divers should approach them slowly and quietly to avoid startling them, as they can produce slime when threatened. The conservation status of this species is currently unknown, indicating that further research is needed to assess its population dynamics and potential threats.