Tennessee Naturalist Program Tennessee Reptiles and Amphibians Scutes, Scales, and Skin Enhanced Study Guide 7/2018 Tennessee Naturalist Program www.tnnaturalist.org Inspiring the desire to learn and share Tennessee’s nature These study guides are designed to reFlect and reinForce the Tennessee Naturalist Program’s course curriculum outline, developed and approved by the TNP Board oF Directors, For use by TNP instructors to plan and organize classroom discussion and Fieldwork components and by students as a meaningFul resource to review and enhance class instruction. This guide was compiled speciFically For the Tennessee Naturalist Program and reviewed by experts in these disciplines. It may contain copyrighted work From other authors and publishers, used here by permission. No part of this document may be reproduced or shared without consent of the Tennessee Naturalist Program and appropriate copyright holders. 2 Tennessee Reptiles and Amphibians Scutes, Scales, and Skin Objectives Present an overview oF reptiles and amphibians including characteristics particular to these two classes oF animals. Explore their behavior, physiology, and ecology, relating these to habitat needs, environmental adaptations, and ecosystem roles, including human interactions. Introduce common species, their distinguishing characteristics and distribution. Time Minimum 4 hours – 2 in class, 2 in Field Suggested Materials ( * recommended but not required; ** TNP Flash drive) • Reptiles and Amphibians Eastern/Central North America, Third Edition Expanded (Peterson Field Guides), Roger Conant and Joseph T. Collins * • “Vocalizations oF Tennessee Frogs and Toads,” CD, TAMP (available Free upon request) • Tennessee’s Reptiles and Amphibians Enhanced Study Guide, TNP ** Expected Outcomes Students will gain a basic understanding oF 1. general characteristics oF and diFFerences between reptiles and amphibians 2. liFe cycle 3. breeding, juvenile, and adult habits and habitats 4. evolutionary development and ecosystem roles 5. amphibians as bioindicators 6. Frogs and toads oF Tennessee 7. salamanders oF Tennessee 8. lizards, turtles, and snakes oF Tennessee 9. rare species; threats and conservation issues 3 Reptiles and Amphibians Curriculum Outline I. Reptile and Amphibian Characteristics A. Egg diFFerences B. Skin diFFerences C. Claws D. Ectothermic II. Amphibian liFe cycle and associated habitats A. Egg masses B. Larvae and juvenile stages C. Adults, hibernation and migration D. Communication and breeding 1. amplexus in Frogs and toads 2. salamander Fertilization E. Evolutionary development oF salamanders F. Amphibian ecological roles 1. bioindicators III. Amphibians oF Tennessee - Class Amphibia: General Characteristics and IdentiFication A. Order Anura (no tail) - Frogs and Toads (voice ID) 1. Family BuFonidae - true toads 2. Family Pelobatidae - spadeFoot toads 3. Family Hylidae - treeFrogs 4. Family Microhylidae - narrowmouth toads 5. Family Ranidae - true Frogs B. Order Caudata (tail) - Salamanders 1. Family Ambystomatidae - cup mouths 2. Family Salamandridae - newts 3. Family Plethodontidae - lungless 4. Families Cryptobranchidae, Proteidae, Amphiumidae, Sirenidae - giants IV. Reptile LiFe Cycle and Associated Habitats A. Eggs and live birth B. Adults, breeding, shedding, hibernation (hibernacula) C. Ecological roles 4 V. Reptiles oF Tennessee - Class Reptilia: General Characteristics and IdentiFication A. Order Testudines - Turtles 1. Family Chelydridae - snapping turtles 2. Family Kinosternidae - musk and mud turtles 3. Family Emydidae - box and water turtles 4. Family Trionychidae - soFtshell turtles B. Order Squamata, Suborder Lacertilia - Lizards 1. Family Polychridae - anoles 2. Family Scincidae - skinks 3. Family Phrynosomatidea, Genus Sceloporus - spiny lizards 4. Family Teiidae - whiptails 5. Family Anguidae - glass lizards C. Order Squamata, Suborder Serpentes - Snakes 1. Family Colubridae - colubrids, typical snakes (non-venomous) 2. Family Viperidae, SubFamily Crotalinae - pit vipers (venomous) VI. Conservation Issues A. Habitat loss B. Commercial exploitation C. Pollution D. Disease 1. Chytrid Fungus 2. Rana virus E. Human misperception VII. Resources A. Publications B. Organizations C. Internet VIII. Review Questions 5 Tennessee Reptiles and Amphibians Tennessee has a rich herpetoFauna. HerpetoFauna are the amphibians and reptiles that occur in an area. The word herpetoFauna comes From the Greek word herpeton meaning “creeping animal.” Tennessee’s amphibians are the Frogs, toads and salamanders. Other amphibians include caecilians but they are Found only in the tropics. Our state’s reptiles are the lizards, turtles and snakes. Other reptiles include alligators, crocodiles and tuataras. A Checklist oF Tennessee Amphibians and Reptiles is in Appendix A. Here is a list oF the numbers oF species oF “herps” that occur in our state. Frogs and Toads – 21 Salamanders – 54 Lizards – 9 Turtles – 15 Snakes – 32 I. Reptile and Amphibian Characteristics DiFFerences between amphibians and reptiles are as Follows. Amphibians Reptiles Have moist skin without scales Dry skin covered in scales Eggs are gelatinous Eggs have a leathery shell No claws on toes When Feet are present, toes have claws Both amphibians and reptiles are ectothermic (cold-blooded) meaning that their body temperature is determined by the temperature oF their environment. They are also both vertebrates. II and III. Amphibians -- Order Anura, Frogs and Toads A Frog is an amphibian, an animal that lives part oF its liFe in water and part oF its liFe on land. Frogs and toads are members oF a group oF animals called anurans. In Latin this means “a” (no) and “nuran” (tail). Thus, they belong to an order which means "no tail." Another name For their order is Salientia which means “to leap.” 6 Eggs and Tadpoles Amphibians are born in the water and hatch From gelatinous eggs into tadpoles or pollywogs. The eggs oF amphibians are considered by scientists to be an evolutionary precursor to the land adequate reptilian egg. However, the amphibian egg is a marvel in itselF. Once laid and Fertilized, the amphibian egg takes in water and enlarges. The outer envelope seals the gelatinous contents inside. The enclosed Fluids perForm as a green house capturing the warmth oF the sun and protecting the inner contents. The progeny have a buFFer From dehydration while eggs. Puddles may dry up around egg masses but iF it rains soon the embryos will survive. Once tadpoles, they are not allotted this luxury. If a puddle dries, tadpoles drown in the terrestrial air, not having the lungs to take in atmospheric oxygen. If they can remain wet, the transFormation From tadpole to Frog is magical, and that is why that transFormation is called metamorphosis. A Latin word which means “magical change.” Tadpoles appear to be all head and tail. The word tadpole comes From two words -- "tad" which means toad and "poll" which means head. In other words, a toad that is all head. Tadpoles seem to be a totally diFFerent creatures than the Frog or toad they are to become. They breathe with gills. For the most part, they are vegetarians eating with scraping mouth parts that scour the surFaces oF rocks and vegetation For algae. In relation to their size, their intestinal tracts are very long to be able to digest cellulose. As time goes on, they develop legs. Back legs First and then Front, resulting in a Four legged creature. Their intestines shrink. Their gills transForm into lungs. Their mouth parts become equipped to eat meat. This includes their incredibly long, Fast action, Fly-snatching tongue. The time required For these events to occur depends on the species oF Frog, temperature, Food availability, etc. It takes at least one year and sometimes two years For bullFrog tadpoles to metamorphose. SpadeFoot toads on the other hand can transForm in less than a month. AFter metamorphosis, the tadpoles become Froglets, tiny replicas oF their adult parents, who in most cases leFt the pond aFter the breeding season and egg laying were complete. Once metamorphosed, many Frog species leave the pond or temporary body oF water in which they were born. OFten times, Froglets or toadlets leave the pond in a mass exodus during or immediately Following a rain giving the appearance oF it raining Frogs, as Folks once believed. Some species are more permanently aquatic and spend most oF their lives in or around the water. BullFrogs and green Frogs are the best examples oF aquatic Frog species. Courtship and Breeding As adults, the Frogs and toads Feed and grow, returning to the water annually to breed and lay eggs. Males arrive at the breeding pools First and begin their advertisement call. Frogs make their vocalizations by passing air From their lungs over the vocal chords to the vocal sac, which resonates to make the sound louder. Males’ vocal chords are larger and more developed than those oF Females. Each species oF Frog or toad has a unique advertisement call. Only males sing this courtship song. So unique are these calls that just as birders can identiFy a bird species by its song, Froggers can identiFy Frog species by their calls. Hence, you can know which species oF Frogs live at your pond without having to see them. 7 Once a pair have agreed to breed, male and Female Frogs enter the mating position. This position is called amplexus. The male clasps the Female From behind. He places his Front arms around her body and clasps her behind her Front legs. Males will oFten have swollen thumbs so that they can better grip the Female.