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Aneides lugubris
Arboreal Salamander
Subgenus: Aneides
family: Plethodontidae
subfamily: Plethodontinae

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Conservation Status (definitions)
IUCN (Red List) Status Least Concern (LC)
See IUCN account.
NatureServe Status Use NatureServe Explorer to see status.
CITES No CITES Listing
Other International Status None
National Status Not presently on any endangered species lists
Regional Status Population numbers appear to be declining

   

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bookcover 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.

Aneides lugubris (Hallowell, 1949)
Arboreal Salamander

Nancy L. Staub1
David B. Wake2

1. Historical versus Current Distribution. Arboreal salamanders (Aneides lugubris) occur in coastal oak woodlands from northern California (Humboldt County) to approximately Valle Santo Tomás, Baja California del Norte, Mexico. Their range includes South Farallon, Santa Catalina, Los Coronados, and Año Neuvo Islands (Lynch and Wake, 1974; McPeak, 2000). In the foothills of the Sierra Nevada, a geographically isolated cluster of populations occurs in black oak and yellow pine forests (Lynch and Wake, 1974). This group of populations is genetically distinct from coastal populations (Jackman, 1993). The range of arboreal salamanders is similar to the range of the oaks (Quercus agrifolia and Q. wislizenii), presumably a consequence of shared moisture and soil characteristics (Rosenthal, 1957). However, in southern California, arboreal salamanders are frequently associated with sycamores (Platanus racemosa) bordering seasonal streams.

Populations have certainly been eliminated as coastal California habitats have been developed, but the species survives in many urbanized regions where adequate cover is present.

2. Historical versus Current Abundance. Although Arboreal salamanders remain common in many areas, in some areas populations have declined in the past 20 yr (D.B.W., personal observations). Petranka (1998) suggests that large oaks used for nesting and aestivation should be preserved. The current decline of live oaks in California will have negative effects on arboreal salamander populations.

3. Life History Features. Reproduction is terrestrial.

A. Breeding.

i. Breeding migrations. Breeding migrations do not occur, but seasonal or daily vertical migrations into and out of trees are possible.

ii. Breeding habitat. Unknown. During courtship a courting male places his mental gland on the female’s dorsum and, in a succession of quick strokes, draws the mental gland across the female’s back (Arnold, 1977). During this behavior, the male’s large and monocuspid premaxillary teeth may scratch the female’s skin and enable efficient delivery of mental gland pheromones to the female’s circulation.

B. Eggs.

i. Egg deposition sites. Reported oviposition sites include in decay holes of live oak trees (most common), under rocks set deeply in the ground, in logs, under surface cover objects (e.g., stone slabs, flower box), and beneath the ground surface (Ritter and Miller, 1899; Ritter, 1903; Storer, 1925). Egg clutches have been found ≤ 9 m above ground in live oak trees (Ritter, 1903). Most females oviposit in late spring or early summer (Stebbins, 1951; Anderson, 1960).

ii. Clutch size. The number of eggs in a clutch varies from 5–24 (Ritter, 1903; Storer, 1925; Stebbins, 1951), with larger females producing more eggs (Anderson, 1960). Ovarian counts range from 5–26 maturing oocytes (Anderson, 1960). Females on densely populated islands tend to produce fewer eggs than females in less dense mainland populations (Anderson, 1960). Eggs are large, 7–9.5 mm in diameter.

C. Direct Development.

i. Brood sites. The same as egg deposition sites.

ii. Parental care. Females are often found coiled around the eggs; males are often in attendance as well (Ritter and Miller, 1899; Ritter, 1903; Stebbins, 1951). After an approximately 3–4-mo developmental period, embryos hatch in August–September at between 26 and 32 mm TL (Storer, 1925; Stebbins, 1951). Presumed family groups may stay associated after hatching (Ritter, 1903).

D. Juvenile Habitat. Similar to that of adults.

E. Adult Habitat. Arboreal salamanders are found in a variety of terrestrial and arboreal habitats, including under rocks and woody surface cover, in decaying stumps and logs, in decay holes in trees, and in rock crevices (Ritter and Miller, 1899; Ritter, 1903; Storer, 1925; Miller, 1944; Stebbins, 1951; Rosenthal, 1957; Anderson, 1960).

Climbing is facilitated by expanded tips of terminal phalanges and large subdigital pads, as well as by the prehensile tail of the arboreal salamander (Ritter and Miller, 1889). Individuals have been found over 18 m above ground in trees (Ritter and Miller, 1899; Ritter, 1903; Stebbins, 1951). Arboreal salamanders can be found in microhabitats that are drier than those of sympatric salamanders (Storer, 1925; Cohen, 1952; Ray, 1958; Anderson, 1960). This species is generally absent from regions receiving < 25 cm of precipitation per year (Rosenthal, 1957).

F. Home Range Size. Unknown.

G. Territories. Arboreal salamanders are well known for their aggressive tendencies and weaponry. This species has a suite of morphological features that enable a strong, wound inflicting bite. The jaw muscles are hypertrophied, the skull is heavily ossified with especially strong jaws, and both juveniles and adults possess enlarged and flattened, blade-like, monocuspid teeth (other plethodontids possess weaker bicuspid teeth as juveniles; Wake, 1966; Wake et al., 1983). In his description of arboreal salamanders, Cope (1889) writes: “On the whole, the physiognomy is not unlike that of a snapping tortoise.” Scarred individuals are often found in the field (Miller, 1944; N.L.S., personal observation), and Myers (1930b) observed that salamanders housed in the same container bite each others’ tails. In a study of museum specimens, Staub (1993) found that 15% of the examined individuals were scarred, presumably from conspecific attacks. The frequency of scarring did not differ significantly between males and females (Staub, 1993).

H. Aestivation/Avoiding Dessication. Arboreal salamanders are more tolerant of dry conditions than are many species of salamanders and are often among the last salamanders to retreat underground or into tree holes to avoid desiccation (Miller, 1944; Cohen, 1952; Ray, 1958; Petranka, 1998). This species has relatively low rates of water loss compared to other salamanders, possibly due to postural adaptations (curled body and tightly coiled tail) and a rapid rate of water uptake (Cohen, 1952; Ray, 1958).

I. Seasonal Migrations. Not known to occur.

J. Torpor (Hibernation). Not known to occur.

K. Interspecific Associations/Exclusions. Arboreal salamanders are syntopic with California slender salamanders (Batrachoseps attenuatus), wandering salamanders (A. vagrans), and black salamanders (A. flavipunctatus) in regions north of San Francisco Bay. Throughout most of the rest of their range, arboreal salamanders occur in sympatry with Ensatina and a number of species of Batrachoseps. Ecological interactions between these species are not well understood. Maiorana (1978a) showed that there may be competition for food between California slender salamanders and arboreal salamanders when large prey are limited. When large prey items are not limiting however, Lynch (1985) found broad dietary differences between these two species—arboreal salamanders tend to eat a few, large bodied prey in addition to a diverse assortment of other prey items. Arboreal salamanders occasionally prey on Batrachoseps (Storer, 1925; Miller, 1944).

L. Age/Size at Reproductive Maturity. Arboreal salamanders are the largest species of Aneides; mature individuals range in size from 65–100 cm SVL (Lynch and Wake, 1974). Age-size relationships suggest that 3 yr are required to reach maturity (Anderson, 1960). Anderson (1960) reported that the minimum size of sexual maturity was 34 mm SVL for females, though this size seems small for typical females reaching sexual maturity.

M. Longevity. Unknown.

N. Feeding Behavior. Arboreal salamanders are nocturnal and feed most actively under moist/wet conditions. Adults tend to feed on larger prey than juveniles, although Wake et al. (1983) point out that arboreal salamanders of all sizes take a range of prey items. The diet of arboreal salamanders includes millipedes, annelids, snails, and especially coleopterans, hymenopterans (ants), isopterans (termites), isopods (sowbugs), chilopods (centipedes), and lepidopterans (Miller, 1944; Zweifel, 1949; Bury and Martin, 1973; Lynch, 1985). Miller (1944) suggests that fungus is an important component of the diet, but other authors have not confirmed this observation. Relative to syntopic species, arboreal salamanders consume disproportionately larger prey items than expected for individuals of a given body size (Lynch, 1985), and comparative data suggest that arboreal salamanders consume numerous large-sized prey that other species are unable to capture (Bury and Martin, 1973). The structural components of the feeding apparatus are well developed (e.g., well ossified skull; Wake et al., 1983). Despite the large jaws and teeth, prey are typically captured by the tongue and brought fully into the mouth, usually without contacting the marginal dentition (personal observation).

O. Predators. Pacific rattlesnakes (Crotulus viridis helleri) are known predators of arboreal salamanders (Mahrdt and Banta, 1997), and a California scrub jay (Aphelocoma coerulescens) has been observed trying to eat a juvenile arboreal salamander (Rubinoff, 1996).

P. Anti-Predator Mechanisms. Several anti-predatory behaviors have been observed when individuals are startled or attacked: a defensive posture (raising the body stiffly off the ground; Cohen, 1952; Stebbins, 1951), squeaking (Ritter and Miller, 1899; Storer, 1925), rapid movement and jumping (Ritter and Miller, 1899), and biting (Ritter, 1903; Storer, 1925; Stebbins, 1951; Lynch, 1981). Arboreal salamanders will bite terrestrial garter snakes (Thamnophis elegans), and in some cases the snakes can die from the inflicted wounds (Lynch, 1981). Micturition, the act of voiding the bladder when startled, is a novel putative antipredatory behavior that has been documented for arboreal salamanders (Staub and Anderson, 2001).

Q. Diseases. Not reported.

R. Parasites. Two species of nematode (Batracholandros salamandrae, Oswaldocruzia pipiens) have been found in arboreal salamanders (Schad, 1960; Goldberg et al., 1998c).

S. Comments. There are two geographically segregated groups of chromosomally differentiated populations of arboreal salamanders (Sessions and Kezer, 1987). These two karyotypes intergrade in south and east-central Mendocino County (Sessions and Kezer, 1987). Unpublished genetic analyses (allozymes and mitochondrial DNA sequences) show that the chromosomal units do not correlate with patterns of genetic variation (Jackman, 1993). The Farallon Island population is most similar genetically to the nearest mainland population, not populations in the Gabilan mountains to the south as suggested by Morafka (1976; see also Jackman, 1993).

4. Conservation. The range of arboreal salamanders is similar to the range of their oak habitat; oaks are used for nesting and aestivation. The current decline of live oaks in California will have negative effects on arboreal salamander populations.

Populations of arboreal salamanders have certainly been eliminated as coastal California habitats have been developed, but the species survives in many urbanized regions where adequate cover is present.

Nancy L. Staub1
Biology Department
Gonzaga University
Spokane, Washington 99258
staub@gonzaga.edu

And:
Museum of Vertebrate Zoology
3101 Valley Life Sciences Building #3160
University of California
Berkeley, California 94720

David B. Wake2
Museum of Vertebrate Zoology
3101 Valley Life Sciences Building #3160
University of California
Berkeley, California 94720-3160
wakelab@uclink4.berkeley.edu



Literature references for Amphibian Declines: The Conservation Status of United States Species, edited by Michael Lannoo, are here.

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Citation: AmphibiaWeb: Information on amphibian biology and conservation. [web application]. 2014. Berkeley, California: AmphibiaWeb. Available: http://amphibiaweb.org/. (Accessed: Apr 20, 2014).

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