Comprehensive DescriptionRead full entry
Rhyacotriton olympicus has a snout-vent length between 4.1 and 6.2 cm (Stebbins 1985) and tends to be the largest species of Rhyacotriton (Good and Wake 1992). Gaige (1917) originally described R. olympicus with "skin shining, closely pitted, without tubercles". The salamander has 14 costal grooves, one median dorsal groove, and five toes on short, well-developed limbs which fail to meet when adpressed. Toes are distinct and rounded, the third toe being longest, with the second and fourth and first and fifth being equal in length. The snout is rounded, head small and depressed, with nostrils near the end of the snout. The eyes are prominent, and eyelids appear swollen. The tail is shorter than snout-vent length, with strong lateralcompression and keeled above, ending in an obtuse point. The vent is a longitudinal slit with a distinct transverse groove at the posterior end (Gaige 1917). Males have distinct squarish, glandular vent lobes, a trait unique among salamanders (Stebbins 1985; Sever 1988). Stebbins and Lowe (1951) and Good and Wake (1992) described adult coloration as uniformly dark chocolate brown above with the dark dorsal coloration ending distinctly along the side in a wavy line. Ventrally, the salamander is orange yellow with mottling of brownish in the gular area, and with well defined dark spots on the underside of the body and tail.
Stebbins and Lowe (1951) described the aquatic larvae as similar to adults in coloration, but with a more mottled appearance. Very young larvae may have whitish venters, but larger larvae are more similar to adult in ventral coloration. They have short gills and adult proportions and are of the stream larva type(Stebbins 1985).
Rhyacotriton was first described by Gaige (1917) as a member of the hynobiid genus Ranodon. Dunn (1920) placed it in the family Ambystomatidae and it was subsequently placed in its own subfamily, Rhyacitritoninae by Tihen (1958). Regal (1966) placed Rhyacotriton in the subfamily Dicamptodontinae, which was elevated to the family Dicamptodontidae by Edwards (1976). The genus was finally placed in its own family by Good and Wake (1992). Considered to contain only one species, R. olympicus, until the work of Good et al. (1987), thefamily now contains four species , R. olympicus, R. variegatus, R. kezeri, and R. cascadae(Good and Wake 1992).