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Ambystoma macrodactylum croceumSanta Cruz Long-toed Salamander

By Megan Hilt

Geographic Range

The Santa Cruz long-toed salamander is a relict species, previously widespread throughout California after the Pleistocene era, and is now concentrated in the area of Santa Cruz, California.(Hukill 1997) Upon time of its discovery in 1954 until the present, this species has inhabited four locations around Santa Cruz County. They include the cities of Ellicott, Valencia, Seascape, and Bennett.(U.S. Fish and Wildlife Service 1986)

Habitat

These salamanders live in ponds, streams or lagoons in the larval stage. As terrestrial adults, the salamanders live in isolated populations in upland and mixed forests and estivate in aquatic habitats. They favor living conditions that allow their skin to stay moist and cool, and residing under forest litter does just this.(Larson 1997)

  • Aquatic Biomes
  • lakes and ponds
  • rivers and streams

Physical Description

Ambystoma macrodactylum croceum is a small salamander, reaching a full-grown adult length of approximately 127 mm, (5 inches). The body of an adult is a glossy black-charcoal color, with brilliant yellow and orange spots covering its back, decreasing in abundance at the top of the head, and virtually disappearing at the small black eyes. Their head is broad, blunt, and torpedo-shaped.(Duellman and Trueb 1986, Westphal 1996) Two pairs of limbs of approximately equal size are set at right angles from the rib cage.(Ferguson 1961) The four toes on the front legs and five on the back are extremely long. The adult tail is laterally flattened, metamorphosed from the larval stage of a fin. True teeth form a row across the roof of the mouth. In the larval stage, salamanders resemble the adults except that they have caudal fins, four external gill slits on either side of the head, and are a mottled, greenish color.(Duellman and Trueb 1986 Westphal 1996)

Development

Reproduction

The reproductive behavior of Ambystoma macrodactylum croceum is highly unique. After a period of estivation, the salamanders travel great distances to their original breeding site. The males stay for approximately one month, while the females stay for only two weeks. The males spend this time competing with each other for resources in order to increase their fitness, (strength and virility). This increases the brightness of the yellow-orange markings, ultimately augmenting mate sexual preference. In the final courtship ritual, the male nudges the female, and if she is receptive, the male then places his chin on the female's head, rubbing his chin gland in a display of preference. The male then moves away, and the female follows snout-to-tail. The male deposits a mushroom-shaped spermatophore (gelatinous blob of sperm) at the bottom of the lake (pond, or slow-moving stream) for the female. She later takes the spermatophore into her "vent" to fertilize the eggs internally. Approximately 200-400 eggs are laid on a submerged vegetative stalk, and hatch 2-3 weeks later.(Hukill 1997) These jelly-encased eggs are the largest eggs of all salamanders in the area.(Westphal 1996) Larvae live in the pond until about March, when their tails will lose their fin, toes lengthen, and the gills disappear. Sexual maturity is reached at 3-4 years.(U.S. Fish and Wildlife Service 1986)

  • Key Reproductive Features
  • gonochoric/gonochoristic/dioecious (sexes separate)

Behavior

Estivation in the Santa Cruz long-toed salamander is a highly important adaptation to the hot and dry summer climate. In order to stay moist and cool, the salamander burrows deep into the forest floor where it stays throughout the hot summer months.(Duellman and Trueb 1986) With the increased rainfall in November, the salamander emerges and travels to the breeding site.(Hukill 1997) Ambystoma macrodactylum croceum relies on multiple forms of protection from predators. These include flicking its tail and triggering poisonous glands, which form droplets of white poison on its skin .(Westphal 1996)

Food Habits

Both aquatic larvae and terrestrial adults are carnivorous. The larvae primarily eat small aquatic insects and arthropods. The adults also prey upon tree frog tadpoles, earthworms, slugs and various terrestrial insects.(Ferguson 1961)

Economic Importance for Humans: Negative

Much of the 139 acres set aside for the species is of high economic value, which is lost if left undeveloped.

Conservation Status

Since being placed on the first Endangered Species List on March 11, 1967, significant steps have been taken in order to ensure their survival, including the reservation of a 139 acre Ellicott Slough National Wildlife Refuge, in San Francisco Bay, California.(U.S. Fish and Wildlife Service 1986, Westphal 1996) Since the loss of habitat is one major source of impending danger to these salamanders' population, the established refuge has been a large step towards saving this rare species.

Contributors

Megan Hilt (author), University of Michigan-Ann Arbor.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

metamorphosis

A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

References

Duellman, W. E. 1993. Amphibian Species of the World: Additions and Corrections. University of Kansas Printing Service. Lawrence, KS.

Duellman, W. E. and L. Trueb. 1986. Biology of Amphibians. Mc-Graw-Hill, New York, NY.

Ferguson, D. E. 1961. The geographic variation of Ambystoma macrodactylum. American Midland Naturalist 65(2): 311-338.

Frost, D. R. 1985. Amphibian Species of the World. Allen Press and the Association of Systematics Collections. Lawrence, KS.

Hukill, Traci. 1997. A love story. http:www.metroactive.com/summer/salamander-9718.html

Larson, Allan. March 2, 1997. Ambystomatidae- The Mole Salamanders. Dept. of Biology, Washington University, St. Louis, MO. http://biodec.wustl.edu/~larsontl/ambystomatidae.html#TOC1

Larson, Allan. March 2, 1997. Caudata- The Salamanders. Dept. of Biology, Washington University, St. Louis, MO. http://biodec.wustl.edu/~larsontl/caudata.html.

U.S. Fish and Wildlife Service, 1986. Santa Cruz Long-toed Salamander Recovery Plan. U.S. Fish and Wildlife Service, Portland, OR. 64 pp.

Westphal, Mike. 1996. The perilous journey of the Santa Cruz Long-toed Salamander. Tideline. Spring 1996 from Don Edwards San Francisco Bay National Wildlife Refuge. http://www.r1.fws.gov/sfbnwr/salamand.html & http://www.fws.gov/~r9endspp/amphibi2.html#Lnk01

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