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Ozark hellbender
Cryptobranchus alleganiensis bishopi
Courtesy Stan Trauth
Family: Cryptobranchidae
Description: The Ozark hellbender, a subspecies of the Eastern hellbender, is the largest salamander in Arkansas, reaching lengths of nearly two feet. It is characterized by dark dorsal blotching and noticeably pronounced chin mottling as opposed to the dorsal spotting of the Eastern hellbender which has a uniformly colored chin. The Ozark hellbender also differs from the eastern subspecies by having considerably reduced spiracular (gill-like) openings,
smooth skin in the ventral canal system of the pectoral portion of the lateral line system, and smaller overall body size.
| Status: |
Candidate (September 12, 2006) Global Rank: G3G4T2Q State Rank: S2 |
Distribution: The Ozark hellbender is restricted to streams within the Ozark Highlands of northern Arkansas and southern Missouri.
Habitat: Rocky, clear-flowing creeks and rivers, usually where there are large shelter rocks. This salamander is entirely aquatic and depends on cool, flowing, well-oxygenated water. It appears to be intolerant of heavy recreational use of its habitat.
Diet: Ozark hellbenders are nocturnal, emerging at night to forage on aquatic invertebrates and fish. Crayfish are a particularly important component of this salamander’s diet.
Reproduction: Ozark hellbenders reach sexual maturity around six years of age. In Arkansas, mating has been documented as occurring in January. Males excavate saucer-shaped nest sites under large rocks or submerged logs prior to mating. Fertilization of egg is external with females depositing 350-500 eggs within the male’s nest site. Shortly after completing egg deposition, males force females from their nest sites. Males then tend the eggs. Larvae emerge from eggs after 45 to 90 days. Gills are lost by 18 months of age. It is thought that Ozark hellbenders may reach 25 to 30 years of age.
Conservation Status: Relatively large numbers of Ozark hellbenders were documented from Arkansas’s Spring River into the mid-1980s. Since that time period, this species appears to have undergone a precipitous decline across its range. Densities within the Spring River have declined markedly. The decreases in Ozark hellbender range and population size are likely caused by a variety of historic and ongoing activities.
Much of the Ozark hellbender’s habitat has been destroyed or fragmented due to habitat alteration from gravel mining, construction of impoundments, and timber harvesting. Recreational pressures (fishing, boating) on rivers hosting Ozark hellbenders have also increased on an annual basis. Water quality in some areas has been compromised by waste products generated by concentrated animal feeding operations. Chemical contamination of rivers may cause reproductive problems in the form of reduced sperm production and viability. Overutilization of hellbenders for commerce and scientific purposes is also likely contributing to their decline. Most remaining Ozark hellbender populations are small and isolated, making them vulnerable to individual catastrophic events and reducing the likelihood of recolonization after localized extinctions.
