No one knew where Ozark zigzag salamanders (Plethodon angusticlavius Grobman) went in the summer, or where they laid their eggs. There were theories, of course, but all based on the behavior of other salamanders. Then, on July 7, 1999, Department Herpetologist Jeff Briggler and Biologist William L. Puckette stumbled onto a group of brooding females and other adult salamanders in a small cave in the Arkansas Ozarks. They continued their study of the site for the next two years in order to learn more about the reproductive biology and natural history of the species.
Zigzag salamanders are known to thrive in cooler and wetter areas than other salamanders, and they remain on the ground nearly until winter. They are found only in the Ozarks, where they inhabit the caves of the Central Highlands or nearby areas, under rocks and leaf litter, near small streams and on steep hillsides. They are found in the south and southwestern portion of the Missouri Ozarks. Until Briggler and Puckette’s discovery, it had only been theorized that these cold-adapted salamanders retreated deeper into the earth during warmer months, to both escape the heat and produce their young.
The brooding females were discovered in tiny crevices in the cave’s walls, where they were laying tiny clusters of two to eight eggs. The eggs were attached to a central stalk that hung, grape-like, from the roof of each hole in the rock. The females then curled themselves around these stalks in order to defend them from predators—including the other salamanders. When disturbed by the scientists, the females reacted aggressively, with lunges and bites. All of the eggs were deposited by late June to early July and hatching concluded by the beginning of September. Unlike some salamanders, the zigzag does not lay eggs in water, so the young complete their larval phase within the egg, hatching as fully-formed, miniature adults after an incubation period of 65 to 70 days.
Adult zigzags are among the smallest of the salamanders, reaching a length of only 23/8 to 37/8 inches. Males and females are difficult to tell apart, but males are usually smaller and more slender. Individuals may be red-striped, yellow-striped, or unstriped, also known as “leadback.” Interestingly, hatchling colors typically do not match those of their mothers. The zigzag, along with other members of the Plethodontid group, do not have lungs; oxygen is absorbed through their skin and mucous membrane of the mouth. Both genders have 17 to 19 “costal grooves,” vertical indentations along the sides of their bodies. These grooves help distribute moisture across the salamander’s skin, which improves their ability to take in oxygen and regulate their temperature.
The zigzag’s prey consists of tiny arthropods. Mammals, birds, reptiles and even other amphibians may feed on the zigzag, given the chance.
—Nichole LeClair Terrill, photo by Jeff Briggler
To learn more about salamanders, watch this video at www.MissouriConservation.org/21330.
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