Rough-scaled Snake, Tropidechis Günther, 1863

Australian rough-scaled snakes

Distribution map of Rough-scaled Snakes
Distribution map of Rough-scaled Snakes

The rough-scaled snake is a close relative of the tiger snake (Notechis scutatus), with similar venom that causes a similar pathology in bite victims. It has a reputation for being highly aggressive, however, though it will certainly bite if interfered with, it will generally flee rapidly from perceived threats and a large percentage of bites from this species have been to snake collectors and people intentionally handling the snake. It is unusual amongst Australian venomous snakes in having, as its common name indicates, keeled scales. It is an active nocturnal forager that primarily feeds upon frogs, including tree frogs, and is an adept climber.

Distribution: Two disjunct populations in coastal eastern Australia.

Distinguishing characteristics: Relatively slender with a rounded head and large eyes with round pupils, keeled scales (see species account below).

Australian species: One, endemic.

Habitat: See species account below.

Activity: See species account below.

Diet: See species account below.

Reproduction: See species account below.

Venom composition: The venom of the rough-scaled snake is similar to that of the closely related tiger snake (Notechis scutatus). Accordingly, the dominant clinical pathology resulting from bites by this species is venom-induced consumption coagulopathy, caused by procoagulant toxins. Less commonly, the venom may cause neurotoxicity and myotoxicity. At least one fatal envenomation can be definitively attributed to this species and bites should be considered medical emergencies.

The recommended treatment is Seqirus (bioCSL) Tiger Snake Antivenom (TSAV).

Tropidechis carinatus (Krefft, 1863)

Rough-scaled Snake or Clarence River Snake

Distribution: NSW (north-eastern coastal); Qld (south-eastern coastal with isolated population in south-eastern Cape York)

Islands: Fraser Is, Qld.

Length: 700 - 750 mm, occasionally 1.0 m

Distinguishing characteristics: Dorsal scales keeled, in 23 rows at midbody; ventrals 160-185; cloacal plate entire; subcaudals 50-60, all single; seven supralabials; temporolabial scale absent.  Very similar in appearance to the harmless keelback (Tropidonophis mairii) which has 15-17 dorsal scale rows, paired subcaudals and a divided cloacal plate.

Colouration & patterning: Dorsum olive-green to brown with irregular dark cross-bands, more evident on the anterior body than posterior body, venter cream, olive, or yellow, often with black speckling.

Habitat: Coastal creeks, rainforest and wet sclerophyll forest.

Activity: Nocturnally active but sometimes observed basking during the day. Rough-scaled snakes are secretive and generally flee from potential threats, but are willing to bite if molested.

Diet: Rough-scaled snakes primarily feed upon frogs, but will also take small mammals, lizards and occasionally birds.

Reproduction: Ovoviviparous, with litters 5-10, occasionally 18, neonates.

Tropidechis carinatus, the Rough-scaled Snake or Clarence River Snake
Tropidechis carinatus, the Rough-scaled Snake or Clarence River Snake (Photo - Stephen Zozaya)