Smooth toadfish
Species of fish
The smooth toadfish (Tetractenos glaber) is a species of fish in the pufferfish family Tetraodontidae. It is native to shallow coastal and estuarine waters of southeastern Australia, where it is widespread and abundant. French naturalist Christophe-Paulin de La Poix de Fréminville described the species in 1813, though early records confused it with its close relative, the common toadfish (T. hamiltonii). The two are the only members of the genus Tetractenos after going through several taxonomic changes since discovery.
Quick Facts Conservation status, Scientific classification ...
Up to 16 cm (6+1⁄4 in) long with distinctive leopard-like dark markings on its dorsal side, the smooth toadfish has a rounded front and tapers to a narrow tail at the back. Unlike most of its relatives, it does not have prominent spines on its body. Like other pufferfish, it can inflate itself with water or air. It forages for its preferred foods—molluscs and crustaceans—in sand and mud of the bottom sediment. Often an unwanted catch by anglers, the smooth toadfish is highly poisonous because of the tetrodotoxin present in its body, and eating it may result in death.
Taxonomy
French naturalist Christophe-Paulin de La Poix de Fréminville described the smooth toadfish in 1813 as Tetrodon glaber, based on a specimen collected in Adventure Bay in southeastern Tasmania by Claude Riche. This holotype was then catalogued in the collection of French naturalist Alexandre Brongniart, but was subsequently lost; upon his death, Brongniart's collection was bequeathed to the Paris Museum and the specimen did not appear there nor at any other institution. The specific name glaber is from the Latin adjective glăber, meaning "bald". Fréminville's description was overlooked by many subsequent authorities, resulting in the confusion of this species with the closely related common toadfish (Tetractenos hamiltoni); it is unclear with many records which species was being referred to, though those from Victoria and Tasmania belong to this species. This issue in the scientific literature was not fully resolved until 1983.
French naturalist Auguste Duméril erected a new genus in publishing the species as Aphanacanthe reticulatus in 1855 from a description authored by his countryman Gabriel Bibron, who had died suddenly. Later Latinised to Aphanacanthus, it was linked to a presumed type species Tetrodon reticulatus, from a manuscript by Bibron. In 1959, Yseult Le Danois equated this species name to Tetractenos hamiltoni, but New Zealand zoologist Graham Hardy later reviewed the specimens labelled as T. hamiltoni and found that they should be assigned to T. glaber. The genus name Aphanacanthe—not Aphanacanthus, as the original spelling takes priority—would have taken precedence over the current genus name Tetractenos. However, it is a nomen nudum as it does not provide enough detail or information to diagnose or properly describe the species, since Duméril had only written a (French) translation of the genus name—αφανης qui nе parait pas, ἃκανθα, épine ("with no thorns").
British ichthyologist Charles Tate Regan described Spheroides liosomus in 1909 from specimens collected in Melbourne, Hobart, Flinders Island and Port Phillip. He noted its lack of spines compared with specimens of T. hamiltonii, and hence argued that it was a distinct and separate species. Australian biologist Gilbert Whitley equated Regan's description with Fréminville's original naming and gave it the combination Spheroides glaber in 1955, and later Gastrophysus glaber in 1964.
The smooth toadfish was assigned to the genera Tetrodon (now Tetraodon) and Sphaeroides, both of which became wastebasket taxa. The smooth toadfish was assigned to several other genera after it became clear that it fell outside a more restricted definition of Tetr(a)odon, including Torquigener. Recognising that the smooth and common toadfish were distinct enough from other species to warrant their own genus and that no valid genus name existed, Hardy reassigned the two species to the new genus Tetractenos in 1983.
Common names include smooth toadfish, smooth toado, slimey toadfish or smooth blowie. Along with related toadfish species, the smooth toadfish is known in Australia as a "toadie". Gaguni is a Tharawal name for toadfish in the Sydney region, the word recorded by William Dawes as ca-gone in his 1791 diaries of theWith a total adult length of anywhere from 3 to 16 cm (1+1⁄8–6+1⁄4 in), the smooth toadfish has an elongate body with a rounded back and flattened belly. The body narrows posteriorly to the slender tail, and its fins are all elongate and rounded. The dorsal fin has 9 to 11 rays. The pectoral fin has 15 to 18 rays, the first of which is very short. It arises well below the level of the eye. The anal fin has 7–9 rays and caudal fin has 11. The smooth toadfish has a small mouth with thin lips at its apex and a tiny chin. The round eyes are adnate (unable to rotate), their upper border level with the profile of the back and their lower border well above the mouth. In a slightly depressed area just in front of the eyes are two small nipple-shaped structures (papillae) that are the nasal organs. The openings face to the rear of the fish and are closed by flaps attached to the walls closest to the fish's midline. The first pharyngobranchial gill arch is elongated and narrow with many tiny teeth. The smooth toadfish has tiny spines that are entirely within the skin layer; these run along its back from the nasal organs almost to the dorsal fin, and along its sides from the eye to the pectoral fine, and along its underparts from behind its mouth to its vent. The skin is smooth even when the fish is fully inflated. It swallows water or air via a flap in its throat to swell itself up.
The base colour of the upperparts is pale tan to yellow-green, heavily marked with irregular brown spots in a reticulated pattern, and several broad dark brown bands, including ones between the eyes, between the pectoral fins and at the level of the dorsal fin. Reminiscent of a leopard's spots, the reticulated pattern continues on the upper lateral side along the body of the fish, becoming silver-white on the lower lateral parts. The chin and belly are white. The fins have a faint yellow-orange tinge, more noticeably in the tail fin. Fieldwork in Sydney waters found females to be larger and heavier than males. Smooth toadfish grow steadily larger as they grow older, with one 16 cm (6+1⁄4 in) long individual calculated to be 13 years old from examination of its otoliths. Their gonads develop when they reach a total length of about 7–8 cm (2+3⁄4–3+1⁄8 in). The smooth toadfish can be distinguished from the otherwise similar common toadfish by its lack of spines and its larger- and bolder-patterned markings on
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