Geographic Range
The northern spectacled salamander (
Salamandrina perspicillata
) is native to the Palearctic region. The species can be found in northern Italy,
predominantly in the Appenine Mountains. The southern boundary of the northern spectacled
salamander is the province of Caserta, which is in the Campania region of Italy, and
the northern boundary is the province of Pavia, which is in the Lombardy region in
Italy. The species can be found as far west as the west coast of Italy and as far
east as the Marche Region of Italy. Additional sources claim the species can also
be found further east in the Apulia Region of Italy.
- Biogeographic Regions
- palearctic
Habitat
The northern spectacled salamander is primarily terrestrial and lives in heavily forested
habitats in mountainous areas. These forests are damp and shaded, and they contain
large limestone rock formations that provide shelter for the salamander. It can be
found in areas with an elevation as low as 50 meters and as high as 1500 meters, but
it is typically located between 200 meters and 900 meters. The female spectacled salamander
will travel to freshwater habitats, such as ponds, streams, and various temporary
pools of water, to lay eggs.
- Habitat Regions
- terrestrial
- freshwater
- Aquatic Biomes
- lakes and ponds
- rivers and streams
- temporary pools
Physical Description
The northern spectacled salamander is ectothermic and bilaterally symmetrical. Bovero et al. (2006) found the average length of the adult northern spectacled salamander is 106.1 mm and the average snout-vent length is 42.8 mm. The total observed length of the adult northern spectacled salamander ranges from 92 mm to 133 mm and the snout vent length ranges from 36 mm to 50 mm. The female spectacled salamander is usually larger than the male, but no sources have been found to confirm this with exact measurements.
Angelini et al. (2008) found the average total length of the pre-metamorphic spectacled salamander ranges from 17.7 mm to 23.4 mm. The pre-metamorphic salamander does not have ventral pattern coloration.
The adult northern spectacled salamander has a yellow v-shaped spot on its head that
resembles spectacles, which gives the salamander its name. The salamander has areas
of red, white, and black spots on its ventral side. The extremities and tail are red,
and the trunk and body are black and white speckled. The color distribution of the
northern spectacled salamander is unique to each salamander, which allows for differentiation
among other individuals of the same species. Northern spectacled salamanders of the
same population typically resemble each other more closely than spectacled salamanders
from different populations.
- Other Physical Features
- ectothermic
- bilateral symmetry
- Sexual Dimorphism
- female larger
Development
The salamander begins as an egg with a yolk of 1.5 mm to 3.7 mm. The egg hatches within 12 to 37 days as a larva, and the larva is usually 7 mm to 13 mm in length. Metamorphosis occurs when the salamander reaches 20 mm to 35 mm in length, which is usually two to five months after it hatches. The larva does not have any ventral color patterns before metamorphosis, but it develops the ventral color patterns of an adult within a few months after metamorphosis. Similar to tree ring counting, the age of larvae and adults can be determined under a microscope experimentally by counting lines of arrested growth (LAG) in the phalanx, a bone in the toe. One LAG represents one year of growth in the salamander, and sexual maturity is reached in the salamander when the distance between the LAGs narrows drastically.
Sex is difficult to determine in the northern spectacled salamander based on physical
characteristics. The male salamander has a more noticeable opening for the cloaca,
but this is not considered a reliable determination of sex. One behavior that is often
used to determine this salamander's sex is if the salamander is seen in water. The
male avoids water, whereas the female salamander goes to water to lay its eggs.
- Development - Life Cycle
- metamorphosis
Reproduction
The northern spectacled salamander is polygynandrous. Rovelli et al. (2015) found two to four males fertilize the female, on average. The male who is most genetically unlike the female typically fathers the most offspring, which indicates that the female spectacled salamander may be able to detect the amount of genetic variance.
The salamander breeds each year from April to May. The male often begins the mating process by standing on its hind legs and excreting a mucus trail. It is inferred that this mucus trail may release chemical cues to attract females, but this has not been experimentally supported. When a female approaches, the male runs in front of her until she stops moving. If the female does not stop moving, the male stops the pre-mating rituals and waits for another female. If the female stops moving, the male quickly moves his tail back and forth, and the mating salamanders begin to circle each other. Then, the male drops a spermatophore, a sperm packet, in front of the female. The female picks up the spermatophore, and it is moved internally into her cloaca.
While mating, the male can become very aggressive if another male tries to interrupt
the process. The mating male will stop the mating process if it sees another male,
and it will attempt to scare the other male away by biting it. After the intruding
male leaves, the mating male will return to the female and attempt to continue the
mating process.
- Mating System
- polygynandrous (promiscuous)
The northern spectacled salamander is iteroparous and reproduces sexually. The female salamander reaches sexual maturity around four to five years old, but the male age of sexual maturity is unknown. The salamander breeds once yearly from April to May. The salamander has external sperm deposition, but fertilization is internal. The female can store this sperm for up to six months, which is the longest known sperm storage period among all salamanders.
The female salamander is oviparous and lays 20 to 50 eggs. These eggs take 12 to 37
days to hatch in water that is 14 degrees Celsius, but they can take up to 50 days
to hatch in cooler water. The larva is independent as soon as it hatches.
- Key Reproductive Features
- iteroparous
- seasonal breeding
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
- fertilization
- oviparous
- sperm-storing
There is very little parental involvement in the offspring of the northern spectacled
salamander. The female protects the eggs for a short time while she is spawning them,
which can take about 13 days. While spawning, if a predator approaches the eggs, she
begins defending the eggs by creating water currents with her body movements. The
female continues making the currents until the predator gets swept away. If the predator
does not get swept away by the current, the salamander pushes the small predator away
with her head. After the female finishes ovipositing, she leaves the area and no longer
protects the eggs. The male exhibits no parental care beyond the mating process.
- Parental Investment
-
pre-hatching/birth
-
protecting
- female
-
protecting
Lifespan/Longevity
The expected lifespan of the northern spectacled salamander after reaching sexual
maturity is about six to seven years. Because sexual maturity is reached between four
and five years old, the total expected lifespan in the wild is 12 years. In captivity,
the salamander can live between 10 and 12 years. Annual mortality rates are 10-15%,
and the main cause of death is lack of food.
Behavior
The northern spectacled salamander is a motile, terricolous species. The salamander has been located at depths of 20-135 cm under the soil surface during summer and winter. The species has also been seen between 130-170 cm above the surface in rock formations during spring and summer. It is suggested that the spectacled salamander primarily uses both of these locations for shelter and protection against predators.
The species is nocturnal and crepuscular, and it is most active from 1800-0000h. The salamander is most active in dim light and mostly dark conditions. It also tends to be more active during rainy days because the cloud cover provides more dim conditions.
The salamander is mostly solitary, but it is not territorial. The salamander often
shares the same spawning location with other individuals of the species. The communication
among individuals of the species is mostly unknown. The only known social interactions
that have been observed between salamanders occur during the reproduction process.
During reproduction, the individual uses tail movements to communicate with its potential
mate. The salamander does not make physical contact with its mate, which is uncommon
for salamanders.
- Key Behaviors
- terricolous
- nocturnal
- crepuscular
- motile
- solitary
Home Range
The territory size of the northern spectacled salamander (and other members of its genus) is unknown.
Communication and Perception
The northern spectacled salamander uses sight, touch, and vibrations to perceive its environment, but it primarily uses chemical cues. The salamander can detect its own scent trail, which allows the salamander to find its breeding site and stay within its home range. The female salamander uses its scent trail to find its oviposition site.
Tail movement is a major mode of communication between potential mates. The way the
female salamander moves its tail communicates to the male whether she will mate with
him. It is unknown if this tail movement is used as a visual cue or if the tail movement
is used to distribute chemical cues through the air. The male salamander aggressively
moves its tail if it sees another male who may interrupt the mating. If the other
male does not respond to the tail movement, the mating male may bite the other male
until it leaves. Social communication in the northern spectacled salamander outside
of the reproduction process is mostly unknown.
- Other Communication Modes
- scent marks
- Perception Channels
- visual
- tactile
- vibrations
- chemical
Food Habits
The northern spectacled salamander is primarily an insectivore, but spiders, mollusks, and worms can also make up a part of its diet. The main food source of the northern spectacled salamander is springtails (Collembola), spiders (Aranea), and beetle larvae (Coleoptera).
The northern spectacled salamander is the only known salamander with a specialized
diet. The salamander is typically highly specialized on springtails in spring, and
it can be specialized on springtails, spiders, and beetle larvae in autumn. The more
specialized salamander is able to find and catch prey more effectively than the generalist
of the same species. Costa et al. (2015) found that the species is made up mostly
of specialists, which is uncommon among other species.
- Primary Diet
- carnivore
- Animal Foods
- insects
- terrestrial non-insect arthropods
- mollusks
- terrestrial worms
Predation
Piazzini et al. (2011) found that the introduced brown trout ( Salmo trutta ) and the Italian white-clawed crayfish ( Austropotamobius fulcisianus ) are predators to the northern spectacled salamander. The main anti-predator adaptation used by the adult salamander is that it can look dead to predators when it feels threatened, which is known as thanatosis.
A leech (
Trocheta bykowskii
), and two types of caddisfly larvae (
Potamophylax cingulatus
and
Halesus appenninus
) are the main predators of the eggs of the northern spectacled salamander. The eggs
and larvae of the northern spectacled salamander have no known anti-predator adaptations,
but the mother often guards her eggs while laying them to limit predation.
Ecosystem Roles
The northern spectacled salamander preys on springtails (Collembola), which are invertebrate decomposers. Potentially, the salamander plays a role in controlling the populations of these invertebrates in forest environments. Consuming and controlling these populations also aids in nutrient recycling. The salamander, and its eggs, also acts as a food source for the brown trout ( Salmo trutta ), Italian white-clawed crayfish ( Austropotamobius fulcisianus ), a leech ( Trocheta bykowskii ), and two types of caddisfly larvae ( Halesus appenninus and Potamophylax cingulatus ).
Contemporary sources cite that P. Sonsino (1896) found "entozoi", which are generally
parasitic worms not confined to a single phylum, are parasitic to the northern spectacled
salamander. It is difficult to determine the reliability of this source because it
is over 100 years old and in a different language.
Economic Importance for Humans: Positive
The northern spectacled salamander is of little known positive economic importance for humans.
Economic Importance for Humans: Negative
There are no known adverse effects of the northern spectacled salamander on humans.
Conservation Status
The northern spectacled salamander is considered a species of "Least Concern" on the
IUCN Red List, and there is no special status listed for the species on the US Federal
List or the CITES appendices. Water pollution and loss of habitat have affected some
populations of the species but have not caused a drastic decline in the species. An
introduced predator, the brown trout (
Salmo trutta
), is a potential threat to some populations of the salamander. Although this species
is not considered threatened, some ares of Italy have implemented laws to protect
the salamander.
Additional Links
Contributors
Mariah Mays (author), Radford University, Cari Mcgregor (editor), Radford University, Zeb Pike (editor), Radford University, Karen Powers (editor), Radford University, April Tingle (editor), Radford University, Jacob Vaught (editor), Radford University, Tanya Dewey (editor), University of Michigan-Ann Arbor.
- Palearctic
-
living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- terrestrial
-
Living on the ground.
- freshwater
-
mainly lives in water that is not salty.
- forest
-
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
- mountains
-
This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.
- polygynandrous
-
the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.
- iteroparous
-
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
- seasonal breeding
-
breeding is confined to a particular season
- sexual
-
reproduction that includes combining the genetic contribution of two individuals, a male and a female
- fertilization
-
union of egg and spermatozoan
- internal fertilization
-
fertilization takes place within the female's body
- oviparous
-
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
- sperm-storing
-
mature spermatozoa are stored by females following copulation. Male sperm storage also occurs, as sperm are retained in the male epididymes (in mammals) for a period that can, in some cases, extend over several weeks or more, but here we use the term to refer only to sperm storage by females.
- nocturnal
-
active during the night
- crepuscular
-
active at dawn and dusk
- motile
-
having the capacity to move from one place to another.
- solitary
-
lives alone
- scent marks
-
communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them
- visual
-
uses sight to communicate
- tactile
-
uses touch to communicate
- vibrations
-
movements of a hard surface that are produced by animals as signals to others
- chemical
-
uses smells or other chemicals to communicate
- carnivore
-
an animal that mainly eats meat
- insectivore
-
An animal that eats mainly insects or spiders.
- ectothermic
-
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
- 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.
- 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.
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