165.
Neuse River Waterdog
(Necturus lewisi)
NT
Overview
Factors which reduce the water quality in the range of this species are all threats to the Neuse River waterdog. These include physical changes to the watercourse such as channelisation, agricultural pollution including run-off of farm waste and pesticides, and industrial and uban development. The resulting siltation and pollution reduce the habitat quality for the species, and furthermore a variety of pesticides have been found in Neuse River waterdogs. A large proportion of the habitat of the upper Neuse drainage basin has been degraded or destroyed by such practices, and development continues.
Urgent Conservation Actions
Habitat restoration and protected areas are required for this species.
Distribution
North Carolina, USA.
Fact
The origin of the name 'waterdog' and 'mudpuppy' is not known, although it is thought that this might be because the head of these species somewhat resembles a dog's head. Alternatively the name might first have been given to another superficially similar salamander group, the sirens (Siren spp.) which sometimes squeak or yelp like a puppy when handled.

The Neuse River waterdog has been suggested as a candidate for the North Carolina state amphibian.
Evolutionary Distinctiveness
Order: Caudata
Family: Proteidae
The family Proteidae, which contains just six species, separated from its closest relatives 190 million years ago at the beginning of the Jurassic Period.

The evolution of the genus Necturus separated from that of its closest relative, the olm, 140 million years ago at the beginning of the Cretaceous. All five species of Necturus are found in eastern North America, whereas the olm is found in Europe.

The Neuse River waterdog was originally described as a sub-species of the more common mudpuppy (Necturus maculosus) but was elevated to full species status in 1937. This species is considered to be the most primitive form of the genus.
Description
The Neuse River waterdog is a rusty brown colour on the upper side, with dark blueish to black spots scattered across the back and onto the head, where they tend to be smaller. The underside is brown/grey and also has dark spots, but here they are smaller than those on the back. There is a dark line through the eye. This species has smooth skin, a stocky body, a flattened snout with rather squared edges, small limbs with four toes on each foot (most salamanders have five toes on their hind feet), and a tail that is vertically flattened with fins both top and bottom.

Individuals become sexually mature once they reach approximately 100 mm snout to vent length (a measurement not including the tail), at approximately 5-6 years of age, but adults continue to grow to 170 mm (280 mm with the tail included). Adults retain some features normally only seen in young amphibians, including tail fins and three bushy, dark red external gills. This developmental trait is called ‘neoteny’, and has apparently evolved independently in a number of salamander groups.

Larvae measure approximately 16 mm snout to vent when they hatch, and have no spots on their underside, but are spotted on the sides and back. For the first part of their life, larvae have a pale brown stripe from the head to the tail, but this fades with age.
Ecology
Both adult and larval Neuse River waterdog feed on worms, arthropods and molluscs, and larger adults occasionally eat small vertebrates.

Breeding occurs in spring and is aquatic. At this time the couple performs a courtship dance, and after mating the females lay eggs under large rocks at between 25 – 45 cm deep, in shaded areas where currents are not too fast. The clutches, of up to 40 eggs, are guarded by adults; in most observed cases the guarding adult was female, however in one instance a male was found at a nest. Male guarding has not been observed in any related species therefore it is questionable whether this male was actually attending the eggs. Larvae hatch in June or July, and are found in quiet waters.

Individuals construct retreats on the downstream side of rocks or in the stream bank, where they remain during the day. At night the riverdogs become active and leave this cover to feed. These retreats may be territories, implied by the fact that females, and males to a lesser extent, actively defend their retreats; threat displays include flaring and pulsating gills and curling of the upper lip. If displaying fails the waterdog will attack intruders by biting them, although larvae and juvenile Neuse River waterdogs are allowed to enter adult retreats without attack. Another defensive adaptation of this species is the production of toxic skin secretions.

This species is inactive in the summer months when individuals burrow deep into leaf beds are very rarely found, but remains active throughout the winter even when temperatures are below 0o c. It has been suggested that the inactivity in the summer months may be an adaptation to avoid fish predators, which are more active at these times.
Habitat
This is a permanently aquatic species which needs high levels of dissolved oxygen and good water quality. The Neuse River waterdog is generally found in backwaters off the main current, in areas with sandy or muddy substrate. One study found more individuals in larger watercourses (those greater than 15 metres wide and one metre deep. Juveniles are found more often in areas with sandy or gravel substrate.
Distribution
Population Estimate
The Neuse River waterdog can be locally common in pristine areas, with healthy populations known from the Little River and the Trent River in the Neuse system. Likewise, in areas of the Tar River system which are not polluted or affected by reservoir construction populations remain healthy. The species has been severely affected in the Neuse River near Raleigh
Population Trend
Populations of the Neuse River waterdog are declining or have been lost from watercourses where pollution has reduced the water quality.
Status
This salamander is listed as Near Threatened on the IUCN Red List of Threatened Species because of the species' relatively small distribution combined with the known populations declines caused by pollution of the watercourses.

In 1990 the state of North Carolina listed the Neuse River waterdog as a species of special concern, which means that individuals of the species may not be killed, collected, or possessed without a permit from the Wildlife Resources Commission.
Threats
Factors which reduce the water quality in the range of this species are all threats to the Neuse River waterdog. These include physical changes to the watercourse such as channelisation, agricultural pollution including run-off of farm waste and pesticides, and industrial and uban development. The resulting siltation and pollution reduce the habitat quality for the species, and furthermore a variety of pesticides have been found in Neuse River waterdogs. A large proportion of the habitat of the upper Neuse drainage basin has been degraded or destroyed by such practices, and development continues.
Conservation Underway
No populations of Neuse River waterdog are specifically protected, however the species is listed as a species of special concern in North Carolina and state water quality designations are addressing pollution in streams.
Conservation Proposed
Although protected by legislation, it does not seem that much active conservation is occurring for the Neuse River waterdog. Management plans for the species should be drawn up and implemented, and should include further research into the species biology and ecology. Habitat restoration and maintenance is required, and protected areas should be established. Furthermore, an education campaign raising awareness of the conservation status of the species should be employed.
Links
References
AmphibiaWeb: Information on amphibian biology and conservation [web application]. 2006. Berkeley, California: AmphibiaWeb. Available: amphibiaweb. Accessed: 08 December 2006.

Beane, J. and Newman, J. T. 1996. North Carolina Wildlife Profiles – Neuse River waterdog. Division of Conservation Education, North Carolina Wildlife Resources Commission.

Behler, J.L. and King, F.W. 1979. The Audubon Society Field Guide to North American Reptiles and Amphibians. Alfred A. Knopf. New York, NY, USA.

Conant, R. and Collins, J.T. 1998. A Field Guide to the Reptiles and Amphibians of Eastern North America. Houghton Mifflin Company. Boston, Massachusetts.

Frost, Darrel R. 2006. Amphibian Species of the World: an Online Reference. Version 4 (17 August 2006). Electronic Database accessible at: . American Museum of Natural History, New York, USA.

Halliday, T. and Adler, C. (eds.). 2002. The new encyclopedia of reptiles and amphibians. Oxford University Press, Oxford.

IUCN, Conservation International and NatureServe. 2006. Global Amphibian Assessment. Global Amphibian Assessment. Accessed on 08 December 2006.

Maxson, L.R., Moler, P.E. and Mansell,B.W. 1988. Albumin evolution in salamanders of the genus Necturus. Journal of Herpetology. 22:231-235.

Obst, F.J., Richter, K. and Jacob, U. 1984. The Completely Illustrated Atlas of Reptiles and Amphibians for the Terrarium. T.F.H. Publication Inc., N.J., U.S.A.

Petranka, J.W. 1998. Salamanders of the United States and Canada. Smithsonian Institution Press. Washington, D.C.

Viosca Jr, P. 1937. A tentative revision of the genus Necturus with descriptions of three new species from the southern Gulf drainage area. Copeia. 1937:120-138.

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