The following account is modified from Amphibian Declines: The Conservation Status of United States Species, edited by Michael Lannoo (©2005 by the Regents of the University of California), used with permission of University of California Press. The book is available from UC Press.

Batrachoseps incognitus Jockusch, Yanev and Wake, 2001
San Simeon Slender Salamander

Robert W. Hansen¹
David B. Wake²

1. Historical versus Current Distribution. San Simeon slender salamanders (Batrachoseps incognitus) were described in 2001 on the basis of differences in proteins and in DNA sequences of the mitochondrial gene cytochrome b (Jockusch, 1996; Jockusch et al., 2001). San Simeon slender salamanders are found in the Santa Lucia Range in extreme southwestern Monterey County and northern San Luis Obispo County of central coastal California. Although generally found in the mountains, they occur near sea level in the northwesternmost part of their range, where the mountains abruptly meet the ocean just north of the Monterey–San Luis Obispo County line. They range as high as 1,000 m on Pine Mountain and Rocky Butte in northern San Luis Obispo County.

2. Historical versus Current Abundance. Unknown.

3. Life History Features.

A. Breeding. Reproduction is terrestrial.

i. Breeding migrations. Unknown.

ii. Breeding habitat. Unknown.

B. Eggs.

i. Egg deposition sites. Oviposition sites are unknown. Egg attendance by females and communal nesting are unknown for San Simeon slender salamanders.

ii. Clutch size. Unknown.

C. Direct Development. Although unreported, we presume that San Simeon slender salamanders undergo direct development, as is the case with other species of bolitoglossine plethodontids. Dates of hatching are unknown.

D. Juvenile Habitat. Unknown how this may differ from adult habitat.

E. Adult Habitat. San Simeon slender salamanders occur in a range of habitat types included closed and open forest (Jockusch et al., 2001). The type locality is characterized by open forest with yellow pine predominant. Near the Pacific Coast they occur in leaf litter under a closed canopy of laurel and sycamore. Near Rocky Butte in the San Simeon Creek drainage, individuals were found in a forest edge setting, being absent from the well developed oak forest (T. Burkhardt, personal communication).

F. Home Range Size. Unknown.

G. Territories. Unknown.

H. Aestivation/Avoiding Dessication. Unknown. Especially at the northern edge of the range, local weather conditions are strongly influenced by the convergence of the Santa Lucia Range and Pacific Ocean, potentially extending periods of surface activity beyond the rainy season. San Simeon slender salamanders have been found under surface cover from mid January to early June (upper elevations of San Simeon Creek drainage), but undoubtedly this species is active with the first cool, moist weather in the fall.

I. Seasonal Migrations. Unknown.

J. Torpor (Hibernation). Unknown.

K. Interspecific Associations/Exclusions. San Simeon slender salamanders occur in sympatry with black-bellied slender salamanders (B. nigriventris) in the Santa Lucia Range. The overall smaller range of B. incognitus within fragmented, relatively mesic uplands suggests a relict distribution together with possible ecological replacement by B. nigriventris, which enjoys a broader geographical and ecological distribution and occurs in higher densities (Yanev, 1978). However, only B. incognitus occupies the highest elevations within the San Simeon Creek drainage (Pine Mountain, Rocky Butte) in San Luis Obispo County. The ranges of San Simeon slender salamanders and Santa Lucia Mountains slender salamanders (B. luciae) approach one another but do not overlap. Near the Pacific Ocean, the two species are separated by ca. 25 km, while at higher elevation, the gap is ca. 50 km (Jockusch et al., 2001). However, the intervening areas in northern San Luis Obispo and southern Monterey counties have not been adequately explored and distributional details for both species are lacking. Additionally, the ranges of San Simeon slender salamanders and lesser slender salamanders (B. minor) approach to within ca. 15 km in northern San Luis Obispo County (Jockusch et al., 2001). Other plethodontid salamanders occurring within the range of San Simeon slender salamanders include ensatinas (Ensatina eschscholtzii) and arboreal salamanders (Aneides lugubris).

L. Age/Size at Reproductive Maturity. Unknown. Based upon measurements of a small series of San Simeon slender salamanders, males range from 38.3–46.3 (mean 41.7; n = 10) mm SVL, females from 39.2–48.0 (mean 42.8; n = 10) mm.

M. Longevity. Unknown.

N. Feeding Behavior. San Simeon slender salamanders are likely similar to other species of Batrachoseps, which capture small arthropod prey using their projectile tongue.

O. Predators. Unknown, although snakes are likely predators.

P. Anti-Predator Mechanisms. Coiling has been observed and is a common defensive response in Batrachoseps.

Q. Diseases. Unknown.

R. Parasites. Unknown.

S. Comments. Although only recently described, specimens now referred to this species were first collected in 1972. Based on studies of mtDNA and allozymes, San Simeon slender salamanders are placed in a clade containing lesser slender salamanders (B. minor) and northern populations of the garden slender salamander (B. major; Jockusch et al., 2001; Jockusch and Wake, 2002).

4. Conservation. San Simeon slender salamanders occupy a small range and are confirmed from only a few localities. Surveys for this species are potentially difficult owing to its general similarity to the microsympatric and more common black-bellied slender salamander (B. nigriventris); surveys may be further complicated by limited habitat and highly restricted access to privately owned land (Jockusch et al., 2001). This species lacks protected status at state or federal levels.

Acknowledgments. We thank Tim Burkhardt for sharing field observations.

¹ Robert W. Hansen
16333 Deer Path Lane
Clovis, California 93611-9735
rwh13@csufresno.edu

² David B. Wake
Museum of Vertebrate Zoology
3101 Valley Life Sciences Building #3160
University of California
Berkeley, California 94720-3160
wakelab@uclink4.berkeley.edu

Citation: AmphibiaWeb. 2023. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 10 Dec 2023.

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