The Neuse River waterdog, ''Necturus lewisi'', is a medium-sized waterdog, family

Proteidae The family Proteidae is a group of aquatic salamanders found today in the Balkan Peninsula and North America. The range of the genus ''Necturus'' (commonly known as waterdogs or mudpuppies) runs from southern central Canada, through the midwes ...

, found in two rivers of

North Carolina North Carolina () is a state in the Southeastern region of the United States. The state is the 28th largest and 9th-most populous of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, Georgia and So ...

Range

The

range Range may refer to: Geography * Range (geographic), a chain of hills or mountains; a somewhat linear, complex mountainous or hilly area (cordillera, sierra) ** Mountain range, a group of mountains bordered by lowlands * Range, a term used to i ...

of the Neuse River waterdog is limited to the Neuse and Tar-Pamlico River basins in the eastern Piedmont and Coastal Plain of North Carolina.

Appearance and physiology

''N. lewisi'' has a rusty-brown dorsal side with many large, bluish-black spots. The ventral side is dark brown to grey and also spotted. The snout is compressed dorsally and truncated. The tail is compressed laterally and ridged. Each hind limb has four toes, and the

gill A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...

s are dull red and bushy. Sexually active males have sowled cloacae and two enlarged cloacal papillae that point to the rear. Males and females are of a similar size. Adults measure 16.5–28.0 cm from the tip of snout to tip of tail. The young possess a dorsal stripe along their length along with a dark lateral stripe. Males and females become sexually mature after reaching 102 mm and 100 mm, respectively, measured from tip of the snout to the posterior end of the cloaca. This size is reached at 5.5 years in males and 6.5 years in females.

Habitat

Neuse River waterdogs prefer streams with a flow >10 cm/s and streams which are >15 m wide, and 1 m deep, in areas with a hard clay or soil bottom, as well as areas covered with leaf bed. Larvae are found in leaf beds of quieter waters which provide cover and foraging sites. Males have a greater range than females, and both males and females increase their range after moderate rains, but decrease it after large rains (>40 mm). During winter, adults mostly reside in burrows in banks or under granite rocks. During the spring, the adults move to large bedrock outcrops or beneath large boulders in relatively fast current where nesting occurs. Home ranges contain animal

burrow An Eastern chipmunk at the entrance of its burrow A burrow is a hole or tunnel excavated into the ground by an animal to construct a space suitable for habitation or temporary refuge, or as a byproduct of locomotion. Burrows provide a form of sh ...

s or rock overhangs, large flat rocks on sand gravel substrates, and slack-water areas with

detritus In biology, detritus () is dead particulate organic material, as distinguished from dissolved organic material. Detritus typically includes the bodies or fragments of bodies of dead organisms, and fecal material. Detritus typically hosts commun ...

mats of leaves. Adults create retreats by shoveling sand and gravel with their snouts, forming a cavity beneath cover objects. Sometimes,

gravel Gravel is a loose aggregation of rock fragments. Gravel occurs naturally throughout the world as a result of sedimentary and erosive geologic processes; it is also produced in large quantities commercially as crushed stone. Gravel is classifi ...

is picked up in the mouth and moved to the periphery of the retreat. Entrances to these retreats face downstream. Females, and to a lesser extent males, actively defend their retreats from intruders. Threat displays include flaring and pulsating the gills and curling the upper lip. Intruders which do not flee after this display are attacked and bitten, usually on the end of the tail.

Reproduction

Males have sperm in the vasa deferentia from November through May, and females have been found with this sperm from December through May. Females move to nesting sites beneath fast-moving current during the spring. Oviposition occurs in April and May, corresponding to the time when ovarian eggs reach their maximum size.

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 a ...

s are 8–9 mm in diameter and attach to the substrate by a blunt stalk.

Courtship

A pair of Neuse River waterdogs crawl slowly, with the male trailing the female by 2–4 cm. The male positions his snout behind the rear legs of the female when she stops. The female has her gills flared, while the male has his close to the neck. The male then moves across her body at the base of her tail. Once parallel, the male begins to stroke the female with his chin. This stroking begins at the top of the head, moves roughly halfway down the female and back to the head. The female then raises her head each time the male's chin contacts her neck or head. This sequence repeats many times over a period of roughly 18 minutes. The male then circles the female in a clockwise direction while maintaining contact with her. After several slow circles are made, the males moves parallel to the female and places his limbs over her back. The pair remains in this position for 30 minutes and retreats.

Diet and feeding

Adults feed from the mouths of their retreats or move about in search of prey at night. Olfaction and sight play important roles in locating food. Animals are active away from cover at night, and also during raised water levels and increased turbidity. Individuals are inactive when stream temperatures exceed 18 °C. Adults mainly

prey Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill the ...

snail A snail is, in loose terms, a shelled gastropod. The name is most often applied to land snails, terrestrial pulmonate gastropod molluscs. However, the common name ''snail'' is also used for most of the members of the molluscan class Gastro ...

earthworm An earthworm is a terrestrial invertebrate that belongs to the phylum Annelida. They exhibit a tube-within-a-tube body plan; they are externally segmented with corresponding internal segmentation; and they usually have setae on all segments. Th ...

isopod Isopoda is an order of crustaceans that includes woodlice and their relatives. Isopods live in the sea, in fresh water, or on land. All have rigid, segmented exoskeletons, two pairs of antennae, seven pairs of jointed limbs on the thorax, an ...

amphipod Amphipoda is an order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. Amphipods range in size from and are mostly detritivores or scavengers. There are more than 9,900 amphipod species so far descr ...

mayflies Mayflies (also known as shadflies or fishflies in Canada and the upper Midwestern United States, as Canadian soldiers in the American Great Lakes region, and as up-winged flies in the United Kingdom) are aquatic insects belonging to the orde ...

stoneflies Plecoptera is an order of insects, commonly known as stoneflies. Some 3,500 species are described worldwide, with new species still being discovered. Stoneflies are found worldwide, except Antarctica. Stoneflies are believed to be one of the mo ...

caddisflies The caddisflies, or order Trichoptera, are a group of insects with aquatic larvae and terrestrial adults. There are approximately 14,500 described species, most of which can be divided into the suborders Integripalpia and Annulipalpia on the b ...

true flies Flies are insects of the order Diptera, the name being derived from the Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advanced ...

, and fish. Other prey include:

slug Slug, or land slug, is a common name for any apparently shell-less terrestrial gastropod mollusc. The word ''slug'' is also often used as part of the common name of any gastropod mollusc that has no shell, a very reduced shell, or only a smal ...

leech Leeches are segmented parasitic or predatory worms that comprise the subclass Hirudinea within the phylum Annelida. They are closely related to the oligochaetes, which include the earthworm, and like them have soft, muscular segmented bodie ...

es,

spider Spiders ( order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species ...

crayfish Crayfish are freshwater crustaceans belonging to the clade Astacidea, which also contains lobsters. In some locations, they are also known as crawfish, craydids, crawdaddies, crawdads, freshwater lobsters, mountain lobsters, rock lobsters, mu ...

centipede Centipedes (from New Latin , "hundred", and Latin , " foot") are predatory arthropods belonging to the class Chilopoda (Ancient Greek , ''kheilos'', lip, and New Latin suffix , "foot", describing the forcipules) of the subphylum Myriapoda, an ...

millipede Millipedes are a group of arthropods that are characterised by having two pairs of jointed legs on most body segments; they are known scientifically as the class Diplopoda, the name derived from this feature. Each double-legged segment is a resu ...

odonate Odonata is an order of flying insects that includes the dragonflies and damselflies. Members of the group first appeared during the Triassic, though members of their total group, Odonatoptera, first appeared in Late Carboniferous. The two common ...

s, hellgrammites,

beetle Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describ ...

s, caterpillars, and salamanders. Prey of larvae are mainly

ostracods Ostracods, or ostracodes, are a class of the Crustacea (class Ostracoda), sometimes known as seed shrimp. Some 70,000 species (only 13,000 of which are extant) have been identified, grouped into several orders. They are small crustaceans, typical ...

copepods Copepods (; meaning "oar-feet") are a group of small crustaceans found in nearly every freshwater and saltwater habitat. Some species are planktonic (inhabiting sea waters), some are benthic (living on the ocean floor), a number of species have p ...

, mayflies, true flies, and

s. Other prey items of larva include: earthworms, caldocerans,

s, collembolans, odonates, and

along with other insects.

Predation

Mainly preyed on by fish, Neuse River waterdogs produce chemical defenses to ward off these predators.

References

*Petranka, James W. (1998) ''Salamanders of the United States and Canada'', Washington and London: Smithsonian Institution Press.
Global Amphibian Assessment
{{Taxonbar, from=Q2415425 Proteidae Fauna of the Southeastern United States Amphibians described in 1924 Endemic fauna of North Carolina