Taricha sierrae

Geographic Range

Sierra newts diverged from California newts ( Taricha torosa ) 7 to 13 million years ago due to geological constraints within the Sierra Nevada. These constraints include the height of the mountains, the water available in the valleys, and food resources. Sierra newts have a geographic range that includes the Sierra Nevada and the southern Cascades. They are primarily found in the northern and central parts of the Sierra Nevada from Shasta County to Kern County at elevations under 609.6 m, while California newts ( Taricha torosa ) occupies areas south of Tulare County.

• Biogeographic Regions
• nearctic nearctic
  • introduced introduced
  • native native

Habitat

Sierra newts occupy both terrestrial and aquatic environments. They spend most of their lives on land, but return to water for breeding. They mainly use forests, shrublands, grasslands, savannas, and foothills with conifers. During the dry season, they stay in moist parts of these habitats, under woody debris or in animal burrows. While breeding, they use temporary pools, ditches, ponds, slow-moving streams, lakes, and reservoirs.

• Habitat Regions
• temperate temperate
• terrestrial terrestrial
• freshwater freshwater

• Terrestrial Biomes
• chaparral chaparral
• forest forest
• mountains mountains

• Aquatic Biomes
• lakes and ponds
• rivers and streams

• Wetlands
• marsh marsh

Physical Description

Adult Sierra newts measure 7 to 9 cm from snout to vent. They are reddish to brown on their dorsal side, orange to yellow on their ventral side, and have no costal grooves. There is light coloring around their yellow eyes and on their snout that is different from other Taricha species. They also have warty skin, which contains tarichatoxin (tetrodotoxin). The best distinguishing characteristic of Sierra newts is the Y-shaped vomerine teeth pattern on their upper jaw, which is different than the V-shaped pattern in other newts. During the breeding season, the skin of the male becomes smooth and lighter in color, the tail develops a blade, nuptial pads develop on their toes for grasping the female, and their vents enlarge. The skin of females during the breeding season becomes more vascular, their tail may develop a small blade, and their vents become more prominent. Sierra newt larvae are aquatic and can get up to 13 to 14 mm. They are yellow on their dorsal side, with two broad black bands on their back. Older larvae have dark spots that look like blotches on their bodies.

• Other Physical Features
• ectothermic ectothermic
• heterothermic heterothermic
• bilateral symmetry bilateral symmetry
• poisonous poisonous

• Sexual Dimorphism
• sexes colored or patterned differently

Development

Sierra newts have an aquatic larval stage. Eggs hatch 14 to 52 days after they are laid. Depending on the resources available, the larval stage can last 3 to 4 months before metamorphosis results in a terrestrial juvenile. This stage last for 5 to 8 years. An adult will then migrate back to their original breeding grounds, develop sexual features, and reproduce.

• Development - Life Cycle
• metamorphosis metamorphosis

Reproduction

Courtship and mating is similar in all Taricha species, with slight variation on the duration and angle of the body in certain steps of amplexus. Males migrate to the breeding ground a few days before females arrive, and begin to develop features that allow them to become aquatic and sexual. Among these features is the enlargement of their cloacal lips, the vascularization of their skin, and the development of a broad blade on the tail. When the females arrive, her skin also vascularizes but retains some of the terrestrial roughness. It’s also possible for the female to develop a small blade on her tail, but this does not always occur. Once in the water, the skin of the female releases a pheromone that the males respond to quickly. The male will then clasp the female’s torso with his forelimbs and rubs his chin on her nose. The male begins to press his cloaca against her dorsum, while rubbing her nose in lateral movements with his chin for about an hour. Once this ritual is done, he will then move diagonally across her shoulder to lay his spermatophore about 3 centimeters from her head. He then uses lateral movements of his hips to move his dorsum away from her, which causes his spine to bend at a right angle from her, a position termed sacral curvature. Sierra newt males form a sacral curvature shallower than red-bellied newts , but more prominent than California newts . If the female accepts his gift, she will move into a position where her cloaca is in position to collect the spermatophore. If she denies it, she will act like she is coming into position but will then continue past.

• Mating System
• polygynandrous (promiscuous) polygynandrous (promiscuous)

Sierra newts start to migrate to the breeding ground 6 to 8 weeks before the breeding season begins. Males arrive first and start their sexual transformation. There are more males than females generally, so the sooner the male has completed his metamorphosis, the more likely he is to find a mate. Females arrive closer to the end of the migration period and transform. Mating can occur multiple times for both sexes. Females oviposit multiple clutches of 11 to 22 eggs (2.8 to 3.5 mm in diameter) on submerged objects, though the total number of clutches produced by one female in a season is not known. Once deposited, the eggs take 14 to 52 days to incubate. The larval stage then then lasts a few months, depending on water temperature, food availability, and other environmental factors.

• Key Reproductive Features
• iteroparous iteroparous
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• fertilization fertilization
  • internal internal
• oviparous oviparous

Females deposit clutches of fertilized eggs under submerged objects (rocks, vegetation, twigs) to protect their offspring from predation. The clutches of eggs are surrounded by a jelly-like membrane that's toxic.

• Parental Investment
• female parental care female parental care
• pre-fertilization
  • protecting
    • female
• pre-hatching/birth
  • protecting
    • female

Lifespan/Longevity

Data are lacking for the lifespan of Sierra newts. Due to their close phylogenetic relationship to California newts ( Taricha torosa ), its lifespan can be approximated to 21.8 years.

Behavior

Sierra newts have multiple anti-predatory mechanisms, depending on how threatened they feel. When a predator nears, they will stand with their legs out to the side, their head raised back to expose the orange on the ventral surface and their tail will then go straight. This is known as the “unken” reflex. If the predator ignores this warning and attacks, they will be in for a dose of tarichatoxin (tetrodoxin), a neurotoxin that can paralyze, cause seizures, and even kill. This toxin is also present in the eggs of the newt to protect from predators. The presence of the toxin in the embryo suggests that it was transferred from the mother, since tetrodoxin has been shown to come from eating foods that contain it. Low levels are also present in the membrane that surrounds the embryo, but are not related to the embryo toxicity. It is not known how the toxin is present in the membrane at this time. Sierra newts are also known to yelp when picked up. When encountering other newts, they may click and rise up on their legs while wagging their tail. During breeding season, males spend more time in the water looking for a mate. During this time, both male and female adults have been known to eat the eggs of fellow newts and other aquatic vertebrates. Females cannibalize eggs more often than males. Sierra newts are diurnal outside of the mating season but will become nocturnal when migrating to the breeding ground. Adults are both diurnal and nocturnal during the breeding season, and larvae also show this behavior.

• Key Behaviors
• natatorial natatorial
• diurnal diurnal
• nocturnal nocturnal
• motile motile
• sedentary sedentary

Home Range

Most movement of Sierra newts occurs during breeding season, when they have been known to travel up to 1000 m to breed. During the dry season, Sierra newts move very little.

Communication and Perception

Female Sierra newts communicate with future mates by releasing a pheromone. When in danger, they have an “unken” reflex. To communicate with other Sierra newts, a clicking sound is made.

• Communication Channels
• tactile tactile
• acoustic acoustic
• chemical chemical

• Other Communication Modes
• pheromones pheromones

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

Invertebrates are the main food source for adults. These include worms, eggs, crustaceans, insects, and slugs. They are also known to eat opportunistically if a small vertebrate is present, such as a hatchling bird. Larvae eat decomposing organic matter and small aquatic invertebrates.

• Primary Diet
• carnivore carnivore
  • eats terrestrial vertebrates
  • eats eggs
  • insectivore insectivore
  • eats non-insect arthropods
  • molluscivore molluscivore
  • vermivore

• Animal Foods
• birds
• amphibians
• eggs
• insects
• mollusks
• terrestrial worms
• other marine invertebrates

• Other Foods
• detritus detritus

Predation

Garter snakes are common predators of Sierra newts, along with bullfrogs. Garter snakes are resistant to the effects of the tetrodotoxin present throughout the adult newt. When threatened, Sierra newts take a defensive stance, with the limbs to the side, tail straight back, and eyes closed. They also expose the orange on the ventral side as a warning of its toxicity. Both the orange coloring and the toxicity of the newt are anti-predatory mechanisms. Larval newts are preyed on by adult newts and other carnivorous predators because, unlike the egg and adult stages, larval newts are not poisonous.

• Anti-predator Adaptations
• aposematic aposematic

Ecosystem Roles

Sierra newts occupy an intermediate position in their food web. They are consumers of invertebrates and some small vertebrates but are prey to snakes and other larger vertebrates. Larvae play an important role as detritivores and consumers within the aquatic habitats that they occupy. Finally, because they use both terrestrial and aquatic habitats, they connect these systems from an ecosystem perspective.

Economic Importance for Humans: Positive

There are no known positive effects of Sierra newts on humans.

Economic Importance for Humans: Negative

Sierra newts have a neurotoxin called tarichatoxin (tetrodotoxin). It can be found in the eggs and embryos of female newts. This toxin is also present in the skin, glands, blood, muscles, and viscera of both sexes of adult newts, with the skin being most toxic. If ingested in a high enough dose, the neurotoxin found in these newts can kill a human. It has been shown that the tarichatoxin present in one adult newt can kill approximately 2,500 mice.

• Negative Impacts
• injures humans
  • poisonous poisonous

Conservation Status

Sierra newts are not currently listed as an endangered species on any of the conservation sites. Potential threats that could change this status include: stocking of trout that may eat eggs and larvae, introduced bullfrogs, collection for experimentation, and degradation of habitat.

Other Comments

Sierra newts diverged from California newts ( Taricha torosa ) 7 to 13 million years ago. The northern and central clades of Sierra newts diverged from each other 2.6 to 3.4 mya.

Additional Links

AmphibiaWeb

Encyclopedia of Life

Contributors

Chelsea Zahner (author), Indiana University - Purdue University Fort Wayne, Mark Jordan (editor), Indiana University-Purdue University Fort Wayne, Tanya Dewey (editor), University of Michigan-Ann Arbor.

References

Brame, Jr., A. 1968. The Number of Egg Masses and Eggs Laid by the California Newt, Taricha torosa. Journal of Herpetology , 2/3: 169-170.

Chen, A. 2015. "Amphibia Web: Information on Amphibian Biology and Conservation" (On-line). AmphibiaWeb. Accessed April 01, 2015 at http://www.amphibiaweb.org/cgi/amphib_query?rel-common_name=like&rel-family=equals&rel-ordr=equals&rel-intro_isocc=like&rel-description=like&rel-distribution=like&rel-life_history=like&rel-trends_and_threats=like&rel-relation_to_humans=like&rel-comments=like&rel-submittedby=like&max=200&orderbyaw=Family&include_synonymies=Yes&show_photos=Yes&rel-scientific_name=contains&where-scientific_name=Taricha+sierrae&rel-genus=equals&where-genus=&rel-species=equals&where-species=&where-common_name=&where-subfamily=&where-family=any&where-ordr=any&rel-isocc=occurs+in&where-isocc=&rel-species_account=matchboolean&where-species_account=&rel-declinecauses=equals&where-declinecauses=&rel-iucn=begins+with&where-iucn=&rel-cites=equals&where-cites=&where-submittedby= .

Davis, W., V. Twitty. 1964. Courtship Behavior and Reproductive Isolation in the Species of Taricha (Amphibia, Caudata). Copeia , 1964/4: 601-610.

Gall, B., A. Stokes, J. Pett, K. Spivey, S. French, E. Brodie III, E. Brodie Jr.. 2014. Tetrodotoxin concentrations within a clutch and across embryonic development in eggs of the rough-skinned newts ( Taricha granulosa ). Toxicon , 90: 249-254.

Hanifin, C., E. Brodie, Jr, E. Brodie III. 2008. Phenotypic Mismatches Reveal Escape From Arms-Race Coevolution. PLoS Biology , 6/3: e60.

Knapp, R. 2005. Effects of Nonnative Fish and Habitat Characteristics on Lentic Herpetofauna in Yosemite National Park, USA. Biological Conversation , 121/2: 265-279.

Kuchta, S. 2007. Contact Zones and Species Limits: Hybridization Between Lineages of the California Newt, Taricha torosa , in the Southern Sierra Nevada. Herpetologica , 63/3: 332-350.

Kuchta, S., T. An-Ming. 2006. Lineage Diversification on an Evolving Landscape: Phylogeography of the California Newt, Taricha torosa (Caudata: Salamandridae). Biological Journal of Linnean Society , 89: 213-239.

Livezey, R. 1963. Distribution of Some California Amphibians and Reptiles. Herpetologica , 18/4: 279-281.

Mosher, H., J. Wakely, G. Fuhrman, F. Fuhrman, H. Fischer. 1966. The Occurrence of Tetrodotoxin (Tarichatoxin) in Amphibia and the Distribution of the Toxin in the Organs of Newts ( Taricha ). Toxicon , 3/3: 195-203.

Sallhe, S., J. Mecham. 2012. Physiology of the Amphibia 2 . New York: Academic Press, INC.

California Department of Fish and Game. Biology of Decision Species. ICF J&S 00264.08. California: U.S. Fish and Wildlife Service. 2010.

California Department of Fish and Wildlife. California Wildlife Habitat Relationships System. A075. Sacramento, California: California Interagency Wildlife Task Group. 2013.