Lesser Slender Salamander
© 2009 Richard D. Bartlett (1 of 10)
Batrachoseps minor Jockusch, Yanev and Wake, 2001
Robert W. Hansen1
1. Historical versus Current Distribution. Lesser slender salamanders (Batrachoseps minor) were described in 2001. The species is distinguished from related and sympatric forms by differences in allozymes and mitochondrial DNA sequences, as well as small differences in morphology (Jockusch, 1996; Jockusch et al., 2001). They are distinguished from sympatric black-bellied slender salamanders (B. nigriventris) by being somewhat more robust and having longer limbs and larger hands and feet, but the differences are subtle. Lesser slender salamanders have a restricted distribution in the southern Santa Lucia Range of north-central San Louis Obispo County in central coastal California. In the north, they occur immediately north of Black Mountain and range south and east into the drainages of Paso Robles and Santa Rita Creeks. Populations found farther south and west of Atascadero and in the Cuesta Ridge Botanical Area have not been examined for DNA sequences or allozymes but are tentatively assigned to this species. The elevational range is generally 400–640 m.
2. Historical versus Current Abundance. Lesser slender salamanders were once common, but today are difficult to find (Jockusch et al., 2001). Fewer than five of these salamanders have been seen in the past decade despite many attempts to find them. Although some areas within the historical range of this species have been modified for agriculture (i.e., conversion to vineyards), ample habitat remains and there is no obvious reason for this decline in abundnce.
3. Life History Features.
A. Breeding. Reproduction is terrestrial.
i. Breeding migrations. Unknown.
ii. Breeding habitat. Unknown.
i. Egg deposition sites. Oviposition sites are unknown. Egg attendance by females and communal nesting are unknown for this species.
ii. Clutch size. Unknown.
C. Direct Development. Although unreported, we presume that lesser 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. Lesser slender salamanders appear to be restricted to areas that are either higher in elevation or more mesic than surrounding areas (Jockusch et al., 2001). The type locality is a mesic canyon surrounded by relatively more xeric habitats. Here salamanders were collected from a deeply shaded slope with deep leaf litter. Canopy trees include tanbark oak, coast live oak, sycamore, and laurel. Dense shrubs, predominantly poison oak, were also present. A second site, at York Mountain, is characterized by blue oaks and coast live oaks and generally is less heavily shaded.
F. Home Range Size. Unknown.
G. Territories. Unknown.
H. Aestivation/Avoiding Dessication. Unknown but likely, especially in the southwestern portions of the range. Salamander activity closely tracks the rainy season and is strongly influenced by local conditions. Lesser slender salamanders have been found under surface cover from mid November to mid March.
I. Seasonal Migrations. Unknown.
J. Torpor (Hibernation). Unknown.
K. Interspecific Associations/Exclusions. Everywhere lesser slender salamanders are found, they occur in microsympatry with black-bellied slender salamanders (B. nigriventris; Yanev, 1978; Jockusch et al., 2001). However, the overall smaller range of B. minor 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). Other plethodontid salamanders occurring within the range of lesser 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 lesser slender salamanders, males range from 28.4–33.6 (mean 31.0, n = 10) mm SVL, females from 26.5–32.8 (mean 30.1, n = 10) mm SVL. This is the smallest species of Batrachoseps (Jockusch et al., 2001).
M. Longevity. Unknown.
N. Feeding Behavior. Similar to other species of Batrachoseps, lesser slender salamanders likely capture small insect prey using their projectile tongue.
O. Predators. Unknown, although snakes are likely predators.
P. Anti-Predator Mechanisms. Coiling and tail autotomy are common defensive responses in several species of attenuate Batrachoseps.
Q. Diseases. Unknown.
R. Parasites. Unknown.
S. Comments. Although only recently described, specimens now referred to this species were first collected in 1960. Based on studies of mtDNA and allozymes, lesser slender salamanders are placed in a clade containing San Simeon slender salamanders (B. incognitus) and northern populations of the garden slender salamander (B. major; Jockusch et al., 2001; Jockusch and Wake, 2002).
4. Conservation. The naturally small range of this species, together with its apparent decline, merit conservation attention. The three known localities of lesser slender salamanders where specimen allocation to species has been confirmed by examination of DNA sequences occur on privately owned land. Surveys for this species are potentially difficult owing to its general similarity to the microsympatric and more common black-bellied slender salamander. Field surveys using artificial cover objects (plastic garbage bags) may be effective in locating this species and will minimize potential impact to the habitat (Palazzo, 1994; Duncan, 1998).
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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Citation: AmphibiaWeb. 2020. <http://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 8 Aug 2020.
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