Newt, Peninsula


Notophthalmus viridescens piaropicola


Adults reach a length of 7 – 12.4 cm. The peninsula newt is a darker form of the eastern newt and lacks red spots entirely. Individuals range from greenish-brown to almost black and are heavily speckled with black spots. The venter (underside) may also be a deeper orange color than the typical yellow of the other forms.

Family

Salamandridae

Order

Caudata

Class

Amphibia

Range

Restricted to peninsular Florida south of central Alachua County

Habitat

Bodies of freshwater (except fast flowing rivers) associated with deciduous and coniferous forests; most commonly found among hyacinth roots in freshwater, occasionally emerging to walk on floating vegetation.

Life Expectancy

12 – 15 years

Sexual Maturity

3 years

Diet

In the wild, they eat small invertebrates such as insects, small mollusks and crustaceans, young amphibians, and frog eggs; in the Zoo, they are fed black worms, newt bites, and other pelleted foods.

Status

IUCN – Least Concern

Behaviors

The Peninsula newt is a subspecies of the Eastern newt that is found throughout eastern North America. With the aid of its flattened tail, the Peninsula newt moves quickly in water yet is slow on land. Larvae are fairly sedentary, settling at the bottom of the water to hide. They appear to segregate by size in ponds, which probably serves as a defense against larger, cannibalistic adults, however few are lucky enough to survive the first winter. The eft is nocturnal (active during the night) and more active on rainy nights. In dry, sunny weather, the eft will find a cool, moist place to rest and crawl out to feed when damp, darker weather approaches. The adult newt returns to the water and spends the rest of its life there, often foraging both day and night. Winter is spent underground, unless the adults are in permanent water. Carnivorous throughout their lives, these newts use both chemical and visual cues to locate food. Adults seem to rely more on visual cues when feeding. They don’t have a specialized diet, but temperature and water clarity, as well as prey density, can affect the feeding process. The breeding season begins in late winter and lasts until early spring; at this time, the female is heavy with eggs and actively seeking a male. The courtship involves a unique form of amplexus. Females are attracted by the male’s spots and he lures them to him by making fanning motions with his tail and wiggling, causing an enticing odor (a pheromone) to be released. The male positions himself above and forward of the female, gripping her sides just behind her forelegs with his hindlimbs and rubbing her snout with the side of his head. Males will deposit a sperm packet on the bottom of the pond and the female will proceed to pick it up with her cloaca, later using the sperm to fertilize her eggs. Males are often in competition with each other, but rival males who try to break up a pair already involved in amplexus are rarely successful. Sometimes the rival male may drop his sperm packet anyway and the female may pick up the packet when courtship with the other male is over. Male to male courtship is also common. Males tend to eat the sperm packets that are dropped in this case. Oviposition can take several weeks, because the female will only lay a few, widely scattered eggs, each day. It’s still uncertain whether or not females will lay all of their eggs in a breeding season, however they do lay between 200 and 400 single, jelly-covered eggs on submerged vegetation, each season. As soon as the process is finished, the female newt swims away leaving her eggs to survive on their own. Both males and females reach sexual maturity around the age of 3. The incubation of the eggs is somewhat dependent on temperature, but generally lasts from 3 to 8 weeks. In early fall, 3 to 4 months later, the aquatic larvae lose their gills, acquire sac-like lungs (heart transforms from two chambered heart to three, capable of supporting lungs), and emerge onto land as an eft. Two to 3 years later, the eft develops a powerful, flattened tail and returns to the water to breed, as an adult, and remains there the rest of its life, if water is permanent. (Lacking permanent water, adult newts will estivate and overwinter on land and enter vernal ponds in spring to breed.) The Peninsula Newt (N. v. piaropicola) typically skips the red eft stage and metamorphoses directly into an aquatic adult. It is also common for this subspecies to be neotenic, with a larva transforming directly into a sexually-mature adult while retaining its external gills. In other populations, newts enter the eft stage but never undergo a complete second metamorphosis, and enter the water only to breed. Both of these latter two cases may be in response to harsher than average environmental conditions. Females do not provide parental care after they deposit their eggs. Males do not invest in young past sperm production and mating.

Adaptions

Eastern newts home using magnetic orientation. Their magnetoreception system seems to be a hybrid of polarity-based inclination and a sun-dependant compass. Shoreward-bound Eastern newts will orient themselves quite differently under light with wavelengths of ~400 nm than light with wavelengths of ~600 nm, while homing newts will orient themselves the same way under both short and long wavelengths. It is considered very likely that ferromagnetic material, probably biogenic magnetite, is present in the Eastern newt’s body. Members of Salamandridae all have toxic skin secretions that serve as defense against predators.

Special Interests

The eastern newt, Notophthalmus viridescens, is one of only a few species in the Family Salamandridae native to North America. This newt ranges throughout most of eastern North America, from the Canadian Maritime Provinces west to the Great Lakes and south to Texas, Alabama, Georgia, and Florida. There are four recognized subspecies: the red-spotted newt (N. v. viridescens) of the eastern and northeastern U.S. and Canada, the central newt (N. v. louisianensis) of the central states and the Deep South, the broken-striped newt (N. v. dorsalis) of the Carolina coastal plains, and the peninsula newt (N. v. piaropicola) of peninsular Florida. Predators of N. viridescens include birds, mammals, fish, and other amphibians, however many of them are deterred by the newt’s toxic skin secretions. Eastern newts are important predators of small invertebrates in the freshwater ecosystems of eastern North America. Leeches appear to be a major source of adult mortality. Adults will generally flee the water and begin biting or scratching themselves in an attempt to rid their bodies of these ectoparasites, however they’re not always successful. The species name viridescens (Latin, viridis, “green”) refers to the greenish color often found in the adults of this species. The peninsula newt is often found inhabiting beds of water hyacinths (Piaropus), yielding the subspecies name piaropicola (Mecham 1967). The term “newt” has traditionally been seen as an exclusively functional term for salamanders living in water, and not a systematic unit. The relationship between the genera has been uncertain, although it has been suggested that they constitute a natural systematic unit and newer molecular analyses tend to support this position. The oldest form of the name newt is eft, which is still used for newly metamorphosed specimens. According to the Oxford English Dictionary, it changed for unknown reasons first to euft and then to ewt. For some time it remained as an ewt, but the “n” from an shifted to form a newt. The sexually mature stage was also called an ewte, with similar etymology roots linking an ewte, newt, “euft”, and eft: “small lizard-like animal.”

Folklore

Paracelsus suggested that the salamander was the elemental of fire. These “fire salamander” myths likely originate in Europe from the fire salamander, Salamandra salamandra, which hibernates in and under rotting logs. When wood was brought indoors and put on the fire, the creatures mysteriously appeared from the flames. Because of this connection with fire, salamanders have often been associated with dragons. Leonardo da Vinci wrote the following on the salamander: “This has no digestive organs, and gets no food but from the fire, in which it constantly renews its scaly skin. The salamander, which renews its scaly skin in the fire, for virtue.” Early travelers to China were shown garments supposedly woven from salamander wool; the cloth was completely unharmed by fire. The garments had actually been woven from asbestos. They are also tied to activities of witches, as noted in the Shakespeare reference to “eye of newt” being used as an ingredient by the three witches in Macbeth. Truly mythical salamanders have six legs and are highly valued by witches. “Lizards leg” is the hind left leg of one of these mythical beasts. The mythical salamander resembles the real salamander somewhat in appearance, but has six legs and makes its home in fires, the hotter the better. (Similarly, the salamander in heraldry is shown in flames, but is otherwise depicted as a generic lizard.)

Conservation

Many amphibians are facing threats from habitat loss, pollution, over-collecting, introduction of invasive species and diseases. Many are sensitive to pollution.

Jacksonville Zoo History

Peninsula newts have been part of the Jacksonville Zoo animal collection since 2000 and they have successfully bred here.

Exhibit

Wild Florida