Comprehensive DescriptionRead full entry
Head is longer than broad; rectangular when viewed dorsally, truncated when viewed laterally. Eyes laterally placed. Vomeropalatine teeth extending posteriorly to a point near corners of mouth; run parallel then diverge. Nostrils anteriorly placed, distance from each other is less than their distance from eyes. SVL length is approximately three times distance from anterior point of snout to gular fold. Digits long and without webbing; third finger longest, third and fourth toes nearly equal in length. Fingers and toes slightly contact one another when laterally adpressed. Tail laterally compressed; dorsal and ventral fins are parallel and taper at posterior end. Smooth vertebral ridge from neck to tail, running continuous with dorsal fin ridge. Parotoid gland is large, compressed, and almost continuous with a dorso-lateral glandular ridge, which is cut by transverse grooves into a series of bead-like glands; ventro-lateral glandular ridge also present from axilla to groin. Circular gland also present at the antero-dorsal insertion point of the thigh between the two previously mentioned glandular rows. Males are much more glandular during breeding season. Has rugose skin. Dorsum black, sometimes brownish-black, and may sometimes contain small yellow spots on the back along the dorso-lateral glands (Thorn and Raffaelli 2001). Ventral color is brick red, vermilion, carmine, with variable black mottling. Stejneger (1907) describes specimens collected by Dr. Hugh M. Smith from Kiusiu and Shikoku with a black or blackish green dorsum; blood red with dark green mottling or symmetrical streaks ventrally; and in some specimens back is lighter green and sides of tail steel blue. Although most of the specimens look alike, their variation comes from their ventral patterns (Stejneger 1907).
Sexual dimorphism: Thorn and Raffaelli (2001) describe sexual dimorphism in this species. Males are on average smaller than females. Average length of 20 males of Hiroshima: 86.5 mm, average length of 20 females of Hiroshima: 104 mm. Males contain a "filament" at the end of the tail and skin is less rugose. Blue-purplish coloration can be found on the tail, belly, and other parts of males body during the breeding season.
Larvae have limbs with 2 digits and reach a total body length of 45-55 mm (Thorn and Raffaelli 2001) .
Kawamura (1956) and Sawada (19611963a 1963b) studied morphological and behavioral variation in C. pyrrhogaster (then called Triturus pyrrhogaster) across different populations in Japan and concluded that there were 6 races/subspecies.
This subspecies is found along the Atsumi Peninsula, South of Nagoya, Japan. It differs from its conspecifics in having a smaller body size, red dorsal stripe, and two rows of dorsolateral red dots. Males of this subspecies do not develop the characteristic blue-purplish coloration on the tail as most do, but still maintains the thread which develops at the posterior end of the tail.
This subspecies is found on the islands of Kyushu, Shikoku, Oki, and the Chugoku Region, Japan. Some specimens lack the characteristic dark mottling found along with the bright red coloration ventrally, and instead have solid reddish-orange bellies.
Native to Central and Eastern-Central Honshu, Japan. Individuals of this group have a dark brown/black dorsum with reddish-orange bellies mottled with black.
This subspecies is found in Tokyo, Japan. Can be identified from its other conspecifics in have a more defined blunt tail tip, black rows with solid or broken red dorsolateral stripes, and a large red longitudinal stripe ventrally.
This subspecies (Cynops pyrrhogaster sasayame) is distributed in the Kinki Region, Japan. Diagnosed by possessing two irregular black lines running down reddish colored bellies, light colored flecking may run along the sides of the abdomen. The bright ventral coloration usually consists of dense, tiny, bright dots on a black background. This characteristic is distinguishable from the typical black and orange/red mottling found in conspecifics. One behavioral difference is that males elevate one hind limb and place it dorsally on the female while simultaneously undulating their tails, perhaps to direct pheromones to her.
This subspecies is distributed in Northern Honshu, Japan. It is overall larger in body size, and contains more black blotches and lines ventrally than its other conspecifics.