Kings River Slender Salamander
© 2006 William Flaxington (1 of 5)
Batrachoseps regius Jockusch, Wake and Yanev, 1998
Robert W. Hansen1
1. Historical versus Current Distribution. Kings River slender salamanders (Batrachoseps regius) are known from the drainage of the Kings River (Fresno County) on the western slope of the Sierra Nevada of California. The type locality and nearby sites are located on the south and east sides of the North Fork of the Kings River, at elevations of 335–440 m (Jockusch et al., 1998). A second population, provisionally assigned to this species, is known from Summit Meadow, within the South Fork Kings River drainage, at an elevation of 2,470 m and about 37 kilometers east-southeast (direct distance) of the lower elevation sites. The intervening areas within the Kings River drainage (a region of difficult terrain and few roads) have not been surveyed adequately for Batrachoseps, and it seems likely that additional populations of Kings River slender salamanders will be found. More recently, salamanders discovered in the Middle Fork Kaweah River drainage (610 m elevation, Sequoia National Park, Tulare County) have been referred to this species (Jockusch and Wake, 2002); this new find extends the range ca. 29 km south from the nearest Kings River drainage population.
2. Historical versus Current Abundance. The small cluster of sites from the lower elevation Kings River appears to be stable; salamanders have been found here intermittently for the last 25 yr. However, these sites occupy localized habitat immediately adjacent to roads, and thus should be considered vulnerable to alteration. A total of seven specimens have been found at the single high elevation site on two occasions over a 45-yr period.
3. Life History Features.
A. Breeding. Reproduction is terrestrial.
i. Breeding migrations. Unknown.
ii. Breeding habitat. Unknown. For the lower elevation populations, courtship presumably occurs after the start of the rainy season in the fall (November–December), and egg-laying probably takes place from December–January, depending on local rainfall.
i. Egg deposition sites. Nest sites have not been found. The association of the lower elevation populations with talus suggests that eggs may be laid well below ground within the rock/litter matrix. The high elevation population is associated with the wet margins of a seasonally flooded meadow, and it is likely that eggs are laid under or within moist, decomposing logs.
ii. Clutch size. Unknown.
C. Direct Development. Hatchlings have not been observed, but should be expected to appear in late winter to early spring (low elevation sites).
D. Juvenile Habitat. Unknown.
E. Adult Habitat. The lower Kings River sites lie within a mixed pine-oak/chaparral association, characterized by interior live oak, blue oak, foothill pine, and western redbud, with California bay and western sycamore in moist side canyons. Salamanders have been found under scattered granitic rocks (sometimes as talus), downed logs, or within moist sycamore/oak litter at the base of shaded, north-facing slopes and ravines; ferns and mosses are present at some sites (Jockusch et al., 1998; R.W.H., unpublished data).
The lone high-elevation record is for Summit Meadow (2,470 m elevation), located within a moist coniferous forest of lodgepole pine and red fir. This area receives considerable snowfall between November and April. In contrast to the lower elevation sites, surface activity is confined to summer to early fall. One salamander was found inside a rotted lodgepole pine log saturated from surface moisture and lying in deep shade at the margin of a boggy meadow (E.L. Karlstrom field notes, on file at the Museum of Vertebrate Zoology [MVZ]). Specimens have been found here on only two occasions, in May and June, separated by an interval of 45 yr.
F. Home Range Size. Unknown.
G. Territories. Unknown.
H. Aestivation/Avoiding Dessication. At the low elevation sites, salamanders are present under surface cover only during periods of adequate soil moisture—generally from November to March–April. Timing of surface activity varies depending on arrival of fall/winter rains. Individual salamanders presumably move beneath the surface in burrows or rock rubble during dry periods and during the coldest periods in winter. Field body temperatures of 10 salamanders found under cover at the low elevation sites averaged 7.0 ˚C (range 5.2–10.1 ˚C; R.W.H., unpublished data). A single individual found on 9 June at Summit Meadow had a body temperature of 10.2 ˚C (E.L. Karlstrom field notes, on file at MVZ).
I. Seasonal Migrations. Unknown.
J. Torpor (Hibernation). Unknown.
K. Interspecific Associations/Exclusions. Kings River slender salamanders are found with Sierra Nevada ensatinas (Ensatina eschscholtzii platensis), which occupy a comparatively broad range of habitats. The ranges of gregarious slender salamanders (B. gregarius) and Kings River slender salamanders approach, but apparently do not meet, near Pine Flat Reservoir (Fresno County) along the Kings River (Jockusch et al., 1998). These two species undoubtedly come into contact within the Kaweah River drainage. Gregarious slender salamanders have also been found at higher elevations in the Kings River drainage within coniferous forest at sites that appear suitable for Kings River slender salamanders. California newts (Taricha torosa) are widespread at lower elevations in the Kings River drainage and commonly are found at sites where Kings River slender salamanders occur.
L. Age/Size at Reproductive Maturity. This is a moderately small species of Batrachoseps, with maximum adult size ≤ 45 mm SVL (Jockusch et al., 1998). Age and size at sexual maturity are unknown.
M. Longevity. Unknown.
N. Feeding Behavior. Has not been described, although all Batrachoseps species observed thus far use a projectile tongue to capture small invertebrates.
O. Predators. Unknown. Ring-necked snakes (Diadophis punctatus) occur in the lower elevation portion of the range of Kings River slender salamanders and should be considered likely predators.
P. Anti-Predator Mechanisms. Immobility and coiling have been observed when salamanders are first uncovered (R.W.H., unpublished data). The dark dorsal coloration presumably is cryptic against dark substrates and in low-light environments.
Q. Diseases. Unknown.
R. Parasites. Unknown.
S. Comments. Although Yanev (1978, 1980) clearly identified the lower Kings River populations of Batrachoseps as distinctive, formal species recognition did not come until recently (Jockusch et al., 1998), when the formerly wide-ranging B. relictus was partitioned into four species (from north to south in the central and southern Sierra Nevada): B. diabolicus, B. regius, B. kawia, and B. relictus. Recent mtDNA studies (Jockusch, 1996; Jockusch et al., 1998) suggest a sister-taxon relationship between B. regius and B. diabolicus, despite the geographic proximity of B. regius to B. kawia, both of which are now known from the Kaweah River drainage to the south.
Although Jockusch et al. (1998) provisionally assigned specimens collected in 1955 from Summit Meadow (Kings Canyon National Park, elevation 2,470 m) to B. kawia, more recent studies of freshly collected material suggest that this is a high elevation population of B. regius. This leaves a substantial gap in the known distribution of B. regius. Further, the recent discovery of B. regius within the Middle Fork Kaweah River drainage brings this species much closer to populations of its southern relative, B. kawia, which is known from the adjoining East Fork Kaweah River drainage. Additional fieldwork is needed in the upper reaches of the Kings and Kaweah drainages, an area where the ranges of three species (B. regius, B. gregarius, and B. kawia) converge and potentially overlap.
4. Conservation. Kings River slender salamanders occupy a geographically small range and are confirmed from only three areas (one of which [the lower Kings River] consists of a cluster of several sites). Each of these populations appears to be quite localized, and the degree of genetic subdivision suggests that these have been isolated from one another for a long time (Jockusch and Wake, 2002). The lower Kings River sites are located immediately adjacent to a road and likely would be affected by road construction. All localities for Kings River slender salamanders occur on public lands administered by the USDA Forest Service or National Park Service.
Acknowledgments. We thank John Romansic for providing copies of his field notes.
1 Robert W. Hansen
2 David B. Wake
Literature references for Amphibian Declines: The Conservation Status of United States Species, edited by Michael Lannoo, are here.
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