About Aneides vagrans Wake & Jackman, 1999
Aneides vagrans, commonly known as the wandering salamander, is a long, slender species that reaches an approximate snout-vent length of 80 millimetres (3.1 in) and a total length of 130 millimetres (5.1 in). Its base color ranges from brown to light grey, with lighter bronze-grey mottling across its dorsal surface; juveniles additionally have a coppery-bronze stripe running down the spine. This species has between 14 and 16 costal grooves, with 15 being the most common. Males have a broader, more triangular head than females. Like other plethodontid salamanders, wandering salamanders have a pair of naso-labial grooves between the nostrils and mouth that function in chemoreception. They have several adaptations suited to an arboreal lifestyle: relatively long legs, and toes with expanded terminal pads that have square cut ends to help with vertical climbing and gliding. Their prehensile tail is round in cross section, and assists the salamander in directing its descent when falling. The wandering salamander is visually similar to the clouded salamander (Aneides ferreus), and the two were once classified as a single species. The wandering salamander has a disjunct distribution: in California, its range stretches from northern Siskiyou and Del Norte Counties, south along the Pacific coast to northwestern Sonoma County, while it is also widespread across low elevation forests of Vancouver Island and its surrounding islands. The cause of this unusual split range is not confirmed; all existing explanations are unstudied and remain speculative. One hypothesis suggests the species was introduced to Vancouver Island in the nineteenth century, when large sheets of tanoak bark harvested in California were imported for the tanning industry. Wandering salamanders naturally inhabit bark crevices, and multiple leather tanning facilities were built on Vancouver Island in the decades before the species was first recorded there in 1906. There is also documented evidence of extensive tanoak bark importation from San Francisco to Vancouver Island in the late 1800s. Tanoak bark shipped from this region was harvested from both standing and fallen trees, and was typically not treated with harsh chemicals before shipping. This makes it possible for salamanders to be accidentally collected in the bark and survive the journey to Vancouver Island. Even with this circumstantial evidence for the tanoak bark importation theory, questions remain about how salamanders were able to rapidly colonize all of Vancouver Island and its surrounding islets starting from only six tanneries clustered on the southeast coast of the main island. A second theory proposes that the species reached Vancouver Island naturally via log rafting from California, carried north by the Davidson Current. This is the dominant ocean current along the Pacific coast of North America, and during winter it flows along the continental shelf from California to the nearshore waters near Vancouver Island. Before the wandering salamander was split from A. ferreus, another hypothesis suggested the disjunct range formed due to glaciation: the species' originally continuous population was fragmented by glaciers, and surviving populations persisted in glacial refugia in both California and Vancouver Island. Vancouver Island was indeed ice-free during the last glacial maximum, and acted as a refugium for many other species. However, population fragmentation typically leads to genetic divergence over time, so the very close genetic similarity of California and Vancouver Island populations is surprising given the time that has passed since the last glacial period. The wandering salamander occurs at elevations ranging from sea level up to 1,700 metres (5,600 ft). Individuals have very small home ranges, and rarely move far from their territories. Adult wandering salamanders can live in the forest canopy, or in moist terrestrial habitats including rotting logs, bark crevices, stumps, and under rocks. They are more commonly found inside bark on logs than under loose bark on the ground. Individuals can climb as high as 24 m (80 ft) into tree branches, and have been found living in the crowns of coast redwoods. While little research has been done on arboreal microhabitat selection for this species, they appear to associate with epiphytic fern mats growing in the crotches of redwood branches. Breeding occurs in spring and early summer. Females lay a clutch of 6 to 9 eggs in a concealed location; eggs have been found in terrestrial sites such as under logs, as well as at the base of tree branches 30–40 metres (98–131 ft) above ground. Adult salamanders have been observed guarding developing eggs. Wandering salamander eggs hatch directly into miniature adult forms, with no aquatic larval stage.
