The Santa Cruz long-toed salamander (''Ambystoma macrodactylum croceum'') is an

endangered An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching, inv ...

subspecies of the long-toed salamander, which is found only close to a few isolated ponds in Santa Cruz and Monterey Counties in

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

. It has a black body, broken yellow or orange irregular striping along its spine, and a tail fin well evolved for swimming. Like other

mole salamanders The mole salamanders (genus ''Ambystoma'') are a group of Salamandroidea, advanced salamanders endemic to North America. The group has become famous due to the study of the axolotl (''A. mexicanum'') in research on neoteny, paedomorphosis, and t ...

, it is found near pools or slow-moving streams and has a very secretive lifestyle, making it difficult to find.

Comparison with the long-toed salamander

The Santa Cruz long-toed salamander range is geographically separate from other subspecies of the long-toed salamander (''A. macrodactylum'') by over 240 kilometers (150 mi). Whereas the nearest subspecies, ''A. m. sigillatum'' ("Southern long-toed salamander") ranges from

Tuolumne County Tuolumne County (), officially the County of Tuolumne, is a county located in the U.S. state of California. As of the 2020 census, the population was 55,620. The county seat and only incorporated city is Sonora. Tuolumne County comprises the ...

north, the Santa Cruz long-toed salamander is found only near a few isolated

pond A pond is a small, still, land-based body of water formed by pooling inside a depression (geology), depression, either naturally or artificiality, artificially. A pond is smaller than a lake and there are no official criteria distinguishing ...

s in Santa Cruz and Monterey Counties. Like other long-toed salamanders, its belly is sooty to dark brown, and it has

tubercles In anatomy, a tubercle (literally 'small tuber', Latin for 'lump') is any round nodule, small eminence, or warty outgrowth found on external or internal organs of a plant or an animal. In plants A tubercle is generally a wart-like projection, b ...

on its feet. The Santa Cruz long-toed salamander has an irregular broken yellow stripe on its back, whereas the common long-toed salamander has a more regular yellow, vertical stripe. Both species have 12 or 13 costal grooves visible from the side. The Santa Cruz long-toed salamander has a measurable degree of

mitochondrial DNA Mitochondrial DNA (mtDNA and mDNA) is the DNA located in the mitochondrion, mitochondria organelles in a eukaryotic cell that converts chemical energy from food into adenosine triphosphate (ATP). Mitochondrial DNA is a small portion of the D ...

genetic distance Genetic distance is a measure of the genetics, genetic divergence between species or between population#Genetics, populations within a species, whether the distance measures time from common ancestor or degree of differentiation. Populations with ...

from the 'coastal' or 'western' subspecies of long-toed salamander. The genetic relationship, however, is still unclear, as more evidence is needed from additional genes and individuals In both species, eggs are laid singly near the water surface on rush-like spikes, but sometimes in small clusters at the base of logs or sticking to vegetation in the deeper parts of a pond. Hatching

larva A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...

e are about 10 mm long, and in their first summer, they grow to 50 to 100 mm, but the Santa Cruz long-toed salamander is generally considered the smaller species. The precise times of migration for both species, to and from the breeding ponds, occur during periods of sustained nighttime rainfall.

Valencia Lagoon, the modern discovery site

On December 2, 1954, the Santa Cruz long-toed salamander was discovered in Valencia Lagoon by R.W. Russell and James Anderson. This small, seasonal lagoon clogged with

cattails ''Typha'' is a genus of about 30 species of monocotyledonous flowering plants in the family Typhaceae. These plants have a variety of common names, in British English as bulrushStreeter D, Hart-Davies C, Hardcastle A, Cole F, Harper L. 2009. ...

Aptos, California Aptos (Ohlone for "The People") is an unincorporated town in Santa Cruz County, California, United States. The town is made up of several small villages, which together form Aptos: Aptos Hills-Larkin Valley, Aptos Village, Cabrillo, Seacliff, ...

, measured only about 30 m by 150 m (100 ft by 500 ft) at that time.

Caltrans The California Department of Transportation (Caltrans) is an Executive (government), executive department of the U.S. state of California. The department is part of the Government of California#State agencies, cabinet-level California State Tran ...

filled half of the lagoon with a widening of State Route 1 in 1968. The next study of Valencia Lagoon occurred in 1974 by Earth Metrics, whose staff examined the lagoon to develop further migration strategies to allow the creature to better breed and migrate; that study also called for the permanent protection of Valencia Lagoon, which was later effected when the State of California purchased the lagoon.C. Michael Hogan et al., ''Environmental Impact Report for Stern Medical Office Complex, Aptos'', prepared for Santa Cruz County by Earth Metrics Inc., Palo Alto, California. October 15, 1974. Hogan's study also noted the adverse effects of siltation occurring in Valencia Lagoon from the highway embankment erosion created by widening of Route 1; it was reasoned that the

siltation Siltation is water pollution caused by particulate terrestrial clastic material, with a particle size dominated by silt or clay. It refers both to the increased concentration of suspended sediments and to the increased accumulation (temporary o ...

should decrease once the vegetation became re-established on these slopes and allow the habitat to improve; moreover, the Earth Metrics study derived additional mitigation for the County of Santa Cruz to follow in considering any further discretionary actions around Valencia Lagoon.

Life cycle

Most of this salamander's adult life is spent in upland

coast live oak ''Quercus agrifolia'', the California live oak, or coast live oak, is an evergreen live oak native to the California Floristic Province. Live oaks are so-called because they keep living leaves on the tree all year, adding young leaves and sheddi ...

forest in small animal burrows during the long dry season (May to October) in coastal California. Once winter rains have soaked the soil and filled ephemeral streams, both males and females migrate up to 2 km to breeding ponds that exist only in winter. In January, the males arrive at the ponds first, in time to prepare for a nighttime courtship. When the male and female have completed their courtship, the male deposits a packet of sperm, the

spermatophore A spermatophore, from Ancient Greek σπέρμα (''spérma''), meaning "seed", and -φόρος (''-phóros''), meaning "bearing", or sperm ampulla is a capsule or mass containing spermatozoa created by males of various animal species, especiall ...

, in the water, which the female retrieves and uses to

fertilize Fertilisation or fertilization (see spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a zygote and initiate its development into a new individual organism or off ...

her eggs. She may lay the eggs singly or in loose clusters of six to eight eggs in shallow water 5–8 cm deep. Neither parent tends the

egg An egg is an organic vessel grown by an animal to carry a possibly fertilized egg cell (a zygote) and to incubate from it an embryo within the egg until the embryo has become an animal fetus that can survive on its own, at which point the ...

s, which hatch into tadpoles in March and

metamorphose Metamorphosis is a biological process by which an animal physically developmental biology, develops including birth, birth transformation or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through ...

into adult salamanders when the pond begins to dry out. The tadpoles commonly eat small

copepods Copepods (; meaning 'oar-feet') are a group of small crustaceans found in nearly every freshwater and saltwater habitat. Some species are planktonic (living in the water column), some are benthic (living on the sediments), several species have ...

. Predators that eat long-toed salamander larvae include aquatic

invertebrate Invertebrates are animals that neither develop nor retain a vertebral column (commonly known as a ''spine'' or ''backbone''), which evolved from the notochord. It is a paraphyletic grouping including all animals excluding the chordata, chordate s ...

garter snake Garter snake is the common name for small to medium-sized snakes belonging to the genus ''Thamnophis'' in the Family (biology), family Colubridae. They are native to North America, North and Central America, ranging from central Canada in the no ...

s, and other

vertebrates Vertebrates () are animals with a vertebral column (backbone or spine), and a cranium, or skull. The vertebral column surrounds and protects the spinal cord, while the cranium protects the brain. The vertebrates make up the subphylum Vertebra ...

. Other species of salamander tadpoles (larvae) compete with those of the long-toed salamander. The breeding ponds of most species of long-toed salamanders completely dry up during the dry season. The year-round ponds likely harbor frogs, fish, and other aquatic predators that eat young salamanders, so these salamanders prefer ephemeral ponds. Most species of long-toed salamanders migrate up into nearby forests and do not spend any time near the breeding pond once they have metamorphosed and the pond is dry. ''A. m. croceum'' juveniles, though, often spend their first summer close to the breeding pond in a rodent burrow or rock fissure, only later migrating uphill into the forest. This may be because ''A. m. croceum'' breeding ponds retain water all summer.

Conservation status

''Ambystoma macrodactylum croceum'' was designated as federally

in 1967 under the Endangered Species Preservation Act (a precursor to the

Endangered Species Act The Endangered Species Act of 1973 (ESA; 16 U.S.C. § 1531 et seq.) is the primary law in the United States for protecting and conserving imperiled species. Designed to protect critically imperiled species from extinction as a "consequence of e ...

of 1973), and endangered by the State of California in 1971;. It has also been designated as Critically imperiled at the global and state level by

NatureServe NatureServe, Inc. is a non-profit organization based in Arlington County, Virginia, United States, US, that provides proprietary wildlife conservation-related data, tools, and services to private and government clients, partner organizations, and ...

. Its limited range and fragile specialized habitat place severe restrictions to the viability of this species. There is no definitive population estimate for the Santa Cruz long-toed salamander, but the numbers are deemed to be quite small. Further disturbance of its limited habitat could lead to this species' extinction.Bury RB, Ruth SB (1972) "Santa Cruz long-toed salamander: survival in doubt",''Herpetological Review'' 4:20-22

References

External links

Photographs and life history information- California Herps.com

{{Taxonbar, from=Q7419459 Mole salamanders Amphibians of the United States

salamanders Salamanders are a group of amphibians typically characterized by their lizard-like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults. All t ...