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Pseudotriton ruber (Latreille, 1801)
Todd W. Hunsinger1
1. Historical versus Current Distribution. Red salamanders (Pseudotriton ruber) are found from the Hudson River in New York southwestward to Indiana and southward to Louisiana and the Gulf Coast. Four subspecies are currently recognized: northern red salamanders (P. r. ruber), Blue Ridge red salamanders (P. r. nitidus), blackchin red salamanders (P. r. schencki), and southern red salamanders (P. r. vioscai). Red salamanders are naturally absent from much of the Atlantic Coastal Plain and are uncommon on the Coastal Plain of Delaware (Martof, 1975c; J. White, personal communication). Red salamanders are known from only one county in Louisiana, where they are listed as Special Concern. Red salamanders have vanished from places where they historically occurred. For example, Pfingsten (1989g) reported that this species is no longer found near Cincinnati, Ohio. In 1926, Bishop (1927) did not find red salamanders in streams in southwestern New York where they were taken in 1923. In a letter written during fieldwork in the area, Bishop lamented: “Some fine collecting places have been destroyed in the process of 'improving' the park and among them 1 of the 2 known streams for the Red Salamander.” Recent attempts to document red salamanders in this location have failed (unpublished data). Overlooked in previous accounts of red salamanders is a specimen taken on Long Island in 1938 (NYSM3206; Hinderstein, 1968). No further records of red salamanders exist from this locality. Smith (1887) and Deckert (1914c) reported populations east of the Hudson River in New York. The lack of vouchered specimens from these reports and inconsistencies with the known range make these identifications questionable. This sentiment was also reflected in a letter from G. Kingsley Noble to Sherman Bishop dated 23 April 1928. Noble wrote, “Dunn [Emmit Dunn of Smith College] has seen it [Noble, 1927c] and loudly protests against my having left out Deckert’s references. I am convinced that his material was incorrectly identified, but that does not exclude the possibility of the red salamander…being yet found on this side of the Hudson in our region.”
2. Historical versus Current Abundance. Wilmott (1933) stated that red salamanders are not nearly as common as they formerly were on Staten Island, New York. They are also rare in the inner and outer central basins of Tennessee (Redmond and Scott, 1996).
3. Life History Features.
A. Breeding. Reproduction is aquatic.
i. Breeding migrations. There is no true breeding migration for this species. Breeding occurs in the same streams where adults spend much of their lives. Adults will return to the streams in the fall for breeding and egg laying.
ii. Breeding habitat. Ovipositing has rarely been observed. Eggs have been found deposited in springs, headwater streams, and seepage-fed mountain bogs (Bishop, 1941b; Bruce, 1972b, 1978c; Semlitsch, 1983d). Bishop (1925) reported a clutch of eggs found in a tamarack swamp in New York. A simple courtship pattern, including terrestrial components, is proposed for red salamanders and inferred to be ancestral for plethodontids (Organ and Organ, 1968).
i. Egg deposition sites. These eggs were on the lower surface of a large flat rock 15 cm (6 in) below the water surface and buried beneath the sod at the margin of a cold spring (Bishop, 1925).
ii. Clutch size. Clutch sizes range from 29–130 eggs (Bruce, 1978c) with a mean of 80. Bruce concluded that egg laying occurs in autumn. Bishop (1925) reported a single clutch of 72 eggs. Incubation lasts for 2–3 mo (Bishop, 1941b). Hatchlings and late embryos have been reported from November–March. Hatching was inferred to occur in January at 11.2–13.5 mm SVL along the Coastal Plain of South Carolina (Semlitsch, 1983d).
C. Larvae/Metamorphosis. Bruce (2003) confirmed the affinity of larvae for springs. Semlitsch (1983d) revealed that larval growth rates range from 1.2–2.0 mm/mo during the first six months.
i. Length of larval period. The larval period may last from 1.5–3.5 yr, depending on location. Semlitsch (1983d) reported a larval period of only 18–23 mo along the Coastal Plain of South Carolina and suggests that development may be correlated to water temperatures. Length ranged from 45.5–50.0 mm SVL. Bruce (1978c) reported metamorphosis at 31–33 mo in the Blue Ridge Mountains. Gordon (1966) estimated a larval period ranging from 29–33 mo in the Highland Plateau of North Carolina. Based on data from an Ohio population, Pfingsten (1989e) suggests a larval period of 27–31 mo, with metamorphosis at 44 mm SVL. Larvae at 54 mm SVL will probably metamorphose during their fourth year. Bishop (1941b) reported a larval period of 3.5 yr at the northern edge of their range in New York. Bell (1956) reported similar data in Pennsylvania, indicating the same development pattern. Larvae mature at 34–46 mm SVL in the Blue Ridge Mountains of the Carolinas (Bruce, 1972b [It should be noted that Bruce measured SVL to the anterior edge of the cloaca, not to the posterior edge, which is the usual method]). Pfingsten (1989e) reported larvae ranging from 44–52 mm SVL in Ohio. Larvae in a South Carolina population averaged 47.1 ± 0.6 mm SVL (Semlitsch, 1983d). At the northern edge of the range, larvae have been known to exceed 85 mm TL (Bishop, 1941b; Bell, 1956; unpublished data).
ii. Larval requirements.
a. Food. Larvae likely feed on a range of aquatic invertebrates.
b. Cover. Larvae are found underneath logs and rocks or buried in the soft substrate in slower sections of streams. Bruce (1972b) found larvae among accumulations of decaying vegetation in springs, seepage areas, and pools along the course of small streams in the Blue Ridge Mountains. Bahret (1996) reported larvae in a deep acidic lake in New York.
iii. Larvae polymorphisms. Unknown.
iv. Time to metamorphosis. Variable; ranges from 1.5–3.5 yr, depending on location. (see "Length of larval period" above).
v. Post-metamorphic migrations. Unknown.
vi. Neoteny. Unknown.
D. Juvenile Habitat. Likely similar to adult characteristics.
E. Adult Habitat. Adults are aquatic and terrestrial. Aquatic habitat is most often slow-moving headwater springs and seeps in wooded lowland and upland areas. Tamarack wetlands are frequently mentioned in the habitat accounts for red salamanders in New York (Bishop, 1941b; Axtell and Axtell, 1948). Occasionally, individuals are found in swifter streams (Hunsinger and Morse, unpublished data). Adults have been reported from a deep acidic lake in New York (Bahret, 1996). Terrestrial adults are found under rocks, logs, or mats of sphagnum moss (personal observations) in wooded ravines, swamps, open fields, and meadows. Adults use burrows that connect to watercourses (Bishop, 1941b; Axtell and Axtell, 1948). Marvin (2003) examined aquatic and terrestrial burst speeds related to temperature acclimation.
F. Home Range Size. Unknown.
G. Territories. Unknown.
H. Aestivation/Avoiding Dessication. Undocumented.
I. Seasonal Migrations. Adults migrate from the stream to terrestrial habitats on warm rainy nights in early April in New York (unpublished data) and return to the streams for breeding in the late summer or fall. Adults return to the stream in October in New York (Axtell and Axtell, 1948; unpublished data). Most activity occurs in the evening.
J. Torpor (Hibernation). Adults and juveniles are difficult to locate during the winter. For example, I could not locate larvae in a New York stream on 12 December 1998 in sections where they had been easily found on 16 November 1998 (unpublished data), indicating that larvae may cease activity and retreat to deeper underground springs during the winter.
K. Interspecific Associations/Exclusions. Red salamanders share habitat with mountain dusky salamanders (Desmognathus ochrophaeus), northern dusky salamanders (D. fuscus), two-lined salamanders (Eurycea bislineata), and occasionally spring salamanders (Gyrinophilus porphyriticus) in the northern part of their range, and seal salamanders (D. monticola) and black-bellied salamanders (D. quadramaculatus) in southern localities (Bruce, 1974). Semlitsch (1983d) reported mud salamanders (P. montanus), southern dusky salamanders (D. auriculatus), two-lined salamanders (E. bislineata), and long-tailed salamanders (E. longicauda), as well as lesser sirens (Siren intermedia) and two-toed amphiumas (Amphiuma means), in association with red salamanders in the coastal plain of South Carolina. Goin (1939) reports association with slimy salamanders (Plethodon glutinosus) and three-lined salamanders (E. guttolineata) in western Florida.
L. Age/Size at Reproductive Maturity. Bruce (1978c) found sexual maturity in males is reached during their fourth summer, just short of 4 yr old. Females attain sexual maturity at 5 yr and reproduce annually after that. The smallest breeding female was 55 mm SVL.
M. Longevity. Individuals are known to live > 20 yr in captivity (Snider and Bowler, 1992).
N. Feeding Behavior. Diet includes smaller salamanders such as eastern red-backed salamanders (Plethodon cinereus; Bishop, 1941b; Bock and Fauth, 1992), aquatic and terrestrial insects, earthworms, slugs, spiders, and millipedes. Axtell and Axtell (1948) reported water beetles (Hydrophilus sp.), sow bugs (Oniscus sp.) and crickets (Gryllus sp.), in the diet of New York specimens.
O. Predators. Little data are available on known predators. Uhler et al. (1939) found a red salamander in the stomach of a copperhead (Agkistrodon contortrix). I have documented predation by an eastern garter snake (Thamnophis sirtalis; NYSM color slide 20) in New York. Hunsinger and Morse (unpublished data) found red salamanders in association with fishes, including brown trout (Salmo trutta), which are known predators of salamanders (Bishop, 1941b).
P. Anti-Predator Mechanisms. When threatened, individuals assume a defensive posture of raising their hindlimbs and tail, slowly undulating their tail, and tucking their head under their tail. Red salamanders also produce a highly toxic secretion from their dorsal surface (Brandon et al., 1979b; Brandon and Huheey, 1981). Numerous studies have examined possible mimicry with the red eft stage of eastern newts (Notophthalmus viridescens) and spring salamanders (e.g., Brodie, 1976; Brandon et al., 1979b). It is believed that these species form a Mullerian mimicry complex (Brandon et al., 1979b).
Q. Diseases. Unknown.
R. Parasites. Rankin (1937) described the parasites of red salamander larvae from North Carolina as follows: Protozoa—Cryptobia borreli, Cytamoeba bacterifera, Eutrichomastix batrachorum, Hexamastix batrachorum, Heamitus intestinalis, Karotomorpha swezi, Prowazekella longifilis, and Tritrichomonas augusta; Trematoda—Allocreadium pseudotritoni, and intestinal wall metacercariae; Cestoda—proteocephalid cysts. Adults contained the following parasites: Protozoa—Cryptobia borreli, Cytamoeba bacterifera, Prowazekella longifilis, and Tritrichomonas augusta; Trematoda—Allocreadium pseudotritoni, Brachycoelium hospitale, and Gorgoderina bilobata; Cestoda—Crepidobothrium cryptobranchi.
4. Conservation. Red salamanders are listed as Endangered in Indiana (www.in.gov/dnr), as a Species of Special Concern in Louisiana, and as Protected in New Jersey (Levell, 1997). They are known to have vanished from places where they historically occurred (See "Historical versus Current Distribution" above). Other populations appear to be less robust than they were historically (Wilmott, 1933; Redmond and Scott, 1996).
Acknowledgments. The following people assisted with the preparation of this report: Kraig Adler, Jeff Boundy, Scott Smith, and Jim White. This is contribution number 824 of the New York State Museum and Science Service.
1Todd W. Hunsinger
Literature references for Amphibian Declines: The Conservation Status of United States Species, edited by Michael Lannoo, are here.
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