Photos of Reptiles and Amphibians from the North American Southwest

Scientific Name	Common Name	Original Description

Anura	Frogs	Duméril, 1806 (as Anoures)

Anaxyrus (=Bufo)	North American Toads	Tschudi, 1845
Anaxyrus Boreas	Western Toad	(Baird and Girard, 1852)
Anaxyrus boreas boreas (=Bufo boreas boreas)	Boreal Toad	(Baird and Girard, 1852)
Anaxyrus cognatus (=Bufo cognatus)	Great Plains Toad	(Say, 1823)
Anaxyrus debilis	Green Toad	(Girard, 1854)
Anaxyrus debilis insidior (=Bufo debilis insidior)	Western Chihuahuan Green Toad	(Girard, 1854)
Anaxyrus microscaphus (=Bufo microscaphus)	Arizona Toad	(Cope, 1866)
Anaxyrus nelsoni (=Bufo nelsoni)	Amargosa Toad	(Stejneger, 1893)
Anaxyrus punctatus (=Bufo punctatus)	Red-spotted Toad	(Baird and Girard, 1852)
Anaxyrus retiformis (=Bufo retiformis)	Sonoran Green Toad	(Sanders and Smith, 1951)
Anaxyrus williamsi (=Bufo williamsi)	Dixie Valley Toad	Gordon, Simandle & Tracy, 2017
Anaxyrus woodhousii	Woodhouse's Toad	(Girard, 1854)
Anaxyrus woodhousii australis (=Bufo woodhousii australis)	Southwestern Woodhouse's Toad	(Shannon and Lowe, 1955)

Gastrophryne	North American Narrow-mouthed Toads	Fitzinger, 1843
Gastrophryne mazatlanensis	Sinaloan Narrow-mouthed Toad	Hallowell 1856

Hyla	Holarctic Treefrogs	Laurenti, 1768
Hyla arenicolor	Canyon Treefrog	Cope, 1866
Hyla wrightorum	Arizona Treefrog	Taylor, 1939 “1938”

Incilius	Central American Toads	Cope, 1875
Incilius alvarius (=Bufo alvarius)	Sonoran Desert Toad	(Girard, 1859)

Lithobates	American Water Frogs	Fitzinger, 1843
Lithobates catesbeianus (= Rana catesbeiana)	American Bullfrog	(Shaw, 1802)
Lithobates chiricahuensis (=Rana fisheri)	Chiricahua Leopard Frog	(Platz and Mecham, 1979)
Lithobates onca (=Rana onca)	Relict Leopard Frog	(Cope, 1875)
Lithobates pipiens (=Rana pipiens)	Northern Leopard Frog	(Schreber, 1782)
Lithobates tarahumarae	Tarahumara Frog	(Boulenger, 1917)
Lithobates yavapaiensis (=Rana yavapaiensis)	Lowland Leopard Frog	(Platz and Frost, 1984)

Pseudacris	Chorus Frogs	Fitzinger, 1843
Pseudacris maculata	Boreal Chorus Frog	(Wied-Neuwied, 1838)

Smilisca	Mexican Treefrogs	Cope, 1865
Smilisca fodiens (=Pternohyla fodiens)	Lowland Burrowing Treefrog	(Boulenger, 1882)

Scaphiopus	North American Spadefoots	Holbrook, 1836
Scaphiopus couchii	Couch's Spadefoot	Baird, 1854

Spea	Western Spadefoots	Cope, 1866
Spea bombifrons	Plains Spadefoot	(Cope, 1863)
Spea multiplicata	Mexican Spadefoot	(Cope, 1863)
Spea multiplicata stagnalis	Chihuahuan Desert Spadefoot (New Mexico Spadefoot)	(Cope, 1875)

Caudata	Salamanders	Scopoli, 1777

Aneides	Climbing Salamanders	Baird, 1851
Aneides hardii	Sacramento Mountains Salamander	(Taylor, 1941)

Ambystoma	Mole Salamanders	Tschudi, 1838
Ambystoma mavortium	Barred Tiger Salamander	Baird, 1850 “1849”
Ambystoma mavortium mavortium	Barred Tiger Salamander	Baird, 1850 “1849”
Ambystoma mavortium nebulosum	Arizona Tiger Salamander	Hallowell, 1852

Plethodon	Woodland Salamanders	Tschudi, 1838
Plethodon neomexicanus	Jemez Mountains Salamander	Stebbins and Riemer, 1950

Squamata	Lizards	Oppel, 1811

Aspidoscelis	Whiptails	Fitzinger, 1843
Aspidoscelis arizonae	Arizona Striped Whiptail	(Van Denburgh, 1896)
Aspidoscelis exsanguis	Chihuahuan Spotted Whiptail	(Lowe, 1956)
Aspidoscelis gypsi	Little White Whiptail	(Wright and Lowe, 1993)
Aspidoscelis neomexicana	New Mexico Whiptail	(Lowe and Zweifel, 1952)
Aspidoscelis pai	Pai Striped Whiptail	(Wright and Lowe, 1993)
Aspidoscelis sonorae	Sonoran Spotted Whiptail	(Lowe and Wright, 1964)
Aspidoscelis stictogramma	Giant Spotted Whiptail	(Burger, 1950)
Aspidoscelis tigris	Tiger Whiptail	(Baird and Girard, 1852)
Aspidoscelis tigris punctilinealis	Sonoran Tiger Whiptail	(Dickerson,1919)
Aspidoscelis tigris septentrionalis	Plateau Tiger Whiptail	(Burger, 1950)
Aspidoscelis uniparens	Desert Grassland Whiptail	(Wright and Lowe, 1965)
Aspidoscelis velox	Plateau Striped Whiptail	(Springer, 1928)

Callisaurus	Zebra-tailed Lizards	Blainville, 1835
Callisaurus draconiodes	Zebra-tailed Lizard	Blainville, 1835
Callisaurus draconoides myurus	Nevada Zebra-tailed Lizard	Richardson, 1915
Callisaurus draconoides rhodostictus	Western Zebra-tailed Lizard	Cope, 1896
Callisaurus draconoides ventralis	Eastern Zebra-tailed Lizard	(Hallowell, 1852)

Coleonyx	Banded Geckos	Gray, 1845
Coleonyx variegatus	Western Banded Gecko	(Baird, 1859 “1858”)
Coleonyx variegatus bogerti	Tucson Banded Gecko	Klauber, 1945
Coleonyx variegatus utahensis	Utah Banded Gecko	Klauber, 1945

Cophosaurus	Greater Earless Lizards	Troschel, 1852 “1850”
Cophosaurus texanus	Greater Earless Lizard	Troschel, 1852 “1850”
Cophosaurus texanus scitulus	Chihuahuan Greater Earless Lizard	(Peters, 1951)

Crotaphytus	Collared Lizards	Holbrook, 1842
Crotaphytus bicinctores	Great Basin Collared Lizard	Smith and Tanner, 1972
Crotaphytus collaris	Eastern Collared Lizard	(Say, 1823)
Crotaphytus nebrius	Sonoran Collared Lizard	Axtell and Montanucci, 1977

Elgaria	Western Alligator Lizards	Gray, 1838
Elgaria kingii	Madrean Alligator Liard	Gray, 1838)
Elgaria kingii nobilis	Arizona Alligator Lizard	Baird and Girard, 1852)

Gambelia	Leopard Lizards	Baird 1859 “1858”
Gambelia wislizenii	Long-nosed Leopard Lizard	(Baird and Girard, 1852)

Heloderma	Gila Monsters & Beaded Lizards	Wiegmann, 1829
Heloderma suspectum	Gila Monster	Cope, 1869
Heloderma suspectum cinctum	Banded Gila Monster	Bogert and Martin del Campo, 1956
Heloderma suspectum suspectum	Reticulate Gila Monster	Cope, 1869

Hemidactylus	House Geckos	Gray, 1825
Hemidactylus turcicus	Mediterranean Gecko	(Linnaeus, 1758)

Holbrookia	Lesser Earless Lizards	Girard, 1851
Holbrookia elegans	Elegant Earless Lizard	Bocourt, 1874 in Duméril, Mocquard & Bocourt, 1870-1909
Holbrookia elegans thermophila	Sonoran Earless Lizard	Barbour, 1921
Holbrookia maculata	Common Lesser Earless Lizard	Girard, 1851
Holbrookia maculata ruthveni	Bleached Earless Lizard	Smith, 1943

Phrynosoma	Horned Lizards	Wiegmann, 1828
Phrynosoma cornutum	Texas Horned Lizard	(Harlan, 1825)
Phrynosoma goodei	Goode's Desert Horned Lizard	Stejnejer, 1893
Phrynosoma hernandesi	Greater Short-horned Lizard	Girard, 1858
Phrynosoma hernandesi hernandesi	Hernandez's Short-horned Lizard	Girard, 1858
Phrynosoma hernandesi ornatum	Salt Lake Valley Short-horned Lizard	Girard 1858b, comb. nov.
Phrynosoma modestum	Round-tailed Horned Lizard	Girard, 1852
Phrynosoma platyrhinos	Desert Horned Lizard	Girard, 1852
Phrynosoma platyrhinos platyrhinos	Northern Desert Horned Lizard	Girard, 1852
Phrynosoma solare	Regal Horned Lizard	Gray, 1845

Plestiodon	Toothy Skinks	Duméril and Bibron, 1839
Plestiodon callicephalus (= Eumeces callicephalus)	Mountain Skink	(Bocourt, 1879 in Duméril, Mocquard & Bocourt, 1870-1909)
Plestiodon multivirgatus	Many-lined Skink	Hallowell, 1857
Plestiodon multivirgatus epipleurotus	Variable Skink	(Cope, 1880)

Sauromalus	Chuckwallas	Duméril, 1856
Sauromalus ater	Common Chuckwalla	Duméril, 1856

Sceloporus	Spiny Lizards	Wiegmann, 1828
Sceloporus clarkii	Clark's Spiny Lizard	Baird and Girard, 1852
Sceloporus clarkii clarkii	Sonoran Spiny Lizard	Baird and Girard, 1852
Sceloporus clarki vallaris	Plateau Spiny Lizard	Shannon and Urbano, 1954
Sceloporus cowlesi	Southwestern Fence Lizard	Lowe and Norris, 1956
Sceloporus graciosus	Common Sagebrush Lizard	Baird and Girard, 1852
Sceloporus graciosus graciosus	Northern Sagebrush Lizard	Baird and Girard, 1852
Sceloporus jarrovii	Yarrow's Spiny Lizard	Cope, 1875
Sceloporus magister	Desert Spiny Lizard	Hallowell, 1854
Sceloporus poinsetti	Crevice Spiny Lizard	Baird and Girard, 1852
Sceloporus poinsettii poinsettii	New Mexico Crevice Spiny Lizard	Baird and Girard, 1852
Sceloporus slevini	Slevin's Bunch Grass Lizard	Smith, 1937
Sceloporus tristichus	Plateau Fence Lizard (Northern Plateau Lizard)	Cope in Yarrow 1875
Sceloporus uniformis	Yellow-backed Spiny Lizard	Phelan and Brattstrom, 1955
Sceloporus virgatus	Striped Plateau Lizard	Smith, 1938

Uma	Fringe-toed Lizards	1859 “1858”
Uma thurmanae	Mohawk Dunes Fringe-toed Lizard	Derycke, Gottscho, Mulcahy, & De Queiroz, 2020

Urosaurus	Tree and Brush Lizards	Hallowell, 1854
Urosaurus ornatus	Tree Lizard	(Baird and Girard, 1852)
Urosaurus ornatus schottii	Schott's Tree Lizard	(Mittleman, 1940)
Urosaurus ornatus wrighti	Northern Tree Lizard	(Schmidt, 1921)

Uta	Side-blotched Lizards	Baird and Girard in Stansbury 1852
Uta stansburiana	Common Side-blotched Lizard	Baird and Girard, 1852
Uta stansburiana elegans	Western Side-blotched Lizard	Yarrow, 1882
Uta stansburiana stansburiana	Northern Side-blotched Lizard	Baird and Girard, 1852
Uta stansburiana stejnegeri	Eastern Side-blotched Lizard	Schmidt, 1921
Uta stansburiana uniformis	Plateau Side-blotched Lizard	Baird and Girard, 1852

Xantusia	NIght Lizards	Baird, 1859 “1858”
Xantusia arizonae	Arizona Night Lizard	Klauber, 1931
Xantusia bezyi	Bezy's Night Lizard	Papenfuss, Macey, and Schulte, 2001
Xantusia vigilis (utahensis)	Desert Night Lizard (Utah Night Lizard)	Baird, 1859 “1858”

Squamata	Snakes	Oppel, 1811

Arizona	Glossy Snakes	Kennicott, in Baird, 1859
Arizona elegans	Glossy Snake	Kennicott, in Baird, 1859
Arizona elegans philipi	Painted Desert Glossy Snake	Klauber, 1946

Chionactis	Shovel-nosed Snakes	Cope, 1860
Chionactis annulata	Resplendent Desert Shovel-nosed Snake	(Baird, 1859 “1858”)
Chionactis annulata klauberi (Sonora annulata)	Tucson Shovel-nosed Snake	(Stickel, 1941)

Coluber	North American Racers, Coachwhips and Whipsnakes	Linnaeus, 1758
Coluber bilineatis (=Masticophis bilineatis)	Sonoran Whipsnake	(Jan, 1863)
Coluber flagellum	Coachwhip	H. M. Smith, 1941
Coluber flagellum cingulum	Sonoran Coachwhip	Lowe & Woodin, 1954
Coluber flagellum lineatulus	Lined Coachwhip	H. M. Smith, 1941

Crotalus	Rattlesnakes	Linnaeus, 1758
Crotalus atrox	Western Diamond-backed Rattlesnake	Baird and Girard, 1853
Crotalus cerastes	Sidewinder	Hallowell, 1854
Crotalus cerastes cercobombus	Sonoran Sidewinder	Savage and Cliff, 1953
Crotalus cerberus	Arizona Black Rattlesnake	(Coues, 1875)
Crotalus lepidus	Rock Rattlesnake	(Kennicott, 1861)
Crotalus lepidus klauberi	Banded Rock Rattlesnake	Gloyd, 1936
Crotalus molossus	Western Black-tailed Rattlesnake	Baird and Girard, 1853
Crotalus oreganus	Western Rattlesnake	Holbrook, 1840
Crotalus oreganus abyssus (=Crotalus abyssus)	Grand Canyon Rattlesnake	Klauber, 1930
Crotalus oreganus lutosus (=Crotalus lutosus)	Great Basin Rattlesnake	Klauber, 1930
Crotalus pricei	Twin-spotted Rattlesnake	Van Denburgh, 1895
Crotalus pricei pricei	Western Twin-spotted Rattlesnake	Van Denburgh, 1895
Crotalus pyrrhus	Southwestern Speckled Rattlesnake	(Cope, 1867 “1866”)
Crotalus scutulatus	Mohave Rattlesnake	(Kennicott, 1861)
Crotalus scutulatus scutulatus	Northern Mohave Rattlesnake	(Kennicott, 1861)
Crotalus tigris	Tiger Rattlesnake	Kennicott, in Baird, 1859
Crotalus viridis	Prairie Rattlesnake	(RafineWoodburysque, 1818)
Crotalus viridus nuntius	Hopi Rattlesnake	Klauber, 1935
Crotalus willardi	Ridge-nosed Rattlesnake	Meek, 1905
Crotalus willardi obscurus	New Mexico Ridge-nosed Rattlesnake	Harris and Simmons, 1976
Crotalus willardi willardi	Arizona Ridge-nosed Rattlesnake	Meek, 1905

Diadophis	Ring-necked Snakes	Baird and Girard, 1853
Diadophis punctatus	Ring-necked Snake	(Linnaeus, 1766)
Diadophis punctatus regalis	Regal Ring-necked Snake	Baird and Girard, 1853

Gyalopian	Western Hook-nosed Snakes	Cope, 1861
Gyalopion quadrangulare	Thornscrub Hook-nosed Snake	(Günther, 1893 in Salvin and Godman, 1885-1902)

Heterodon	North American Hog-nosed Snakes	Latreille, 1801
Heterodon kennerlyi (= Heterodon nasicus kennerlyi)	Mexican Hog-nosed Snake	Kennicott, 1860

Hypsiglena	North American Nightsnakes	Cope, 1860
Hypsiglena chlorophaea	Desert Nightsnake	Cope, 1860
Hypsiglena chlorophaea chlorophaea (=Hypsiglena torquata chlorophaea)	Sonoran Nightsnake	Cope, 1860
Hypsiglena chlorophaea loreala (=Hypsiglena torquata loreala)	Mesa Verde Night Snake	(Tanner, 1944)

Lampropeltis	Kingsnakes	Fitzinger, 1843
Lampropeltis californiae	California Kingsnake (Western Black Kingsnake)	(Blainville, 1835)
Lampropeltis gentilis	Western Milksnake	Baird and Girard, 1853
Lampropeltis knoblochi (=Lampropeltis pyromelana)	Madrean Mountain Kingsnake (= Arizona Mountain Kingsnake/ Knobloch's Mountain Kingsnake)	Taylor, 1940
Lampropeltis pyromelana	Arizona Mountain Kingsnake	(Cope, 1867)
Lampropeltis splendida	Desert Kingsnake	(Baird and Girard, 1853)

Lichanura	Rosy Boas	Cope, 1861
Lichanura orcutti	Rosy Boa (Desert Rosy Boa)	(Stejneger 1889)
Lichanura trivirgata	Three-lined Boa (Mexican Rosy Boa)	(Cope, 1861)

Micruroides	Sonoran Coral Snakes	Schmidt, 1928
Micruroides euryxanthus	Sonoran Coral Snake	(Kennicott, 1860)
Micruroides euryxanthus euryxanthus	Arizona Coralsnake	(Kennicott, 1860)

Oxybelis	American Vinesnakes	Wagler, 1830
Oxybelis aeneus	Brown Vinesnake	(Wagler, 1824)

Phyllorynchus	Leaf-nosed Snakes	Stejneger, 1890
Phyllorynchus browni	Saddled Leaf-nosed Snake	Stejneger, 1890

Pituophis	Bullsnakes, Pinesnakes, and Gophersnakes	Holbrook, 1842
Pituophis catenifer	Gophersnake	(Blainville, 1835)
Pituophis catenifer affinis	Sonoran Gophersnake	(Hallowell, 1852)
Pituophis catenifer deserticola	Great Basin Gophersnake	Stejneger, 1893

Rena	Threadsnakes	Baird and Girard, 1853
Rena dissectus (=Leptotyphlops dissectus)	New Mexico Threadsnake	(Cope, 1896)

Rhinocheilus	Long-nosed Snakes	Baird and Girard, 1853
Rhinocheilus lecontei	Long-nosed Snake	Baird and Girard, 1853

Salvadora	Patch-nosed Snakes	Baird and Girard, 1853
Salvadora grahamiae	Eastern Patch-nosed Snake	Baird and Girard, 1853
Salvadora grahamiae grahamiae	Mountain Patch-nosed Snake	Baird and Girard, 1853
Salvadora hexalepis	Western Patch-nosed Snake	(Cope, 1866)
Salvadora hexalepis hexalepis	Desert Patch-nosed Snake	(Cope, 1866)

Senticolis	Green Ratsnakes	Dowling and Fries, 1987
Senticolis triaspis	Green Ratsnake	(Cope, 1866)
Senticolis triaspis intermedia	Northern Green Ratsnake	(Boettger, 1883)

Sistrurus	Massasauga & Pygmy Rattlesnakes	Garman, 1883
Sistrurus catenatus	Massasauga	(Rafinesque, 1818)
Sistrurus tergeminus edwardsii	Desert Massasauga	(Baird and Girard, 1853)

Sonora	North American Groundsnakes	Baird and Girard, 1853
Sonora semiannulata	Western Groundsnake	Baird and Girard, 1853
Sonora semiannulata semiannulata	Variable Groundsnake	Baird and Girard, 1853

Tantilla	Black-headed, Crowned, and Flat-headed Snakes	Baird and Girard, 1853
Tantilla hobartsmithi	Smith's Black-headed Snake	Taylor, 1937
Tantilla nigriceps	Plains Black-headed Snake	Kennicott, 1860
Tantilla wilcoxi	Chihuahuan Black-headed Snake	Stejneger, 1903

Thamnophis	North American Gartersnakes	Fitzinger, 1843
Thamnophis cyrtopsis	Black-necked Gartersnake	(Kennicott, 1860)
Thamnophis cyrtopsis cyrtopsis	Western Black-necked Gartersnake	(Kennicott, 1860)
Thamnophis elegans	Terrestrial Gartersnake	(Baird and Girard, 1853)
Thamnophis elegans vagrans	Wandering Gartersnake	(Baird and Girard, 1853)
Thamnophis marcianus	Checkered Gartersnake	(Baird and Girard, 1853)
Thamnophis marcianus marcianus	Marcy's Checkered Gartersnake	(Baird and Girard, 1853)
Thamnophis rufipunctatus	Narrow-headed Gartersnake (Mogollon Narrow-headed Gartersnake)	(Cope, 1875)

Trimorphodon	Lyresnakes	Cope, 1861
Trimorphodon lambda	Sonoran Lyresnake	Cope, 1886

Testudines	Turtles	Linnaeus, 1758

*Gopherus*	Gopher Tortoises	Rafinesque, 1832
Gopherus agassizii	Desert Tortoise	(Cooper, 1863)
Kinosternon	American Mud Turtles	Spix, 1824
Kinosternon arizonense (K. stejnegeri)	Arizona Mud Turtle	(Gilmore, 1922)
Kinosternon sonoriense	Sonora Mud Turtle	LeConte, 1854
Kinosternon sonoriense sonoriense	Desert Mud Turtle Sonoran Mud Turtle Sonora Mud Turtle	LeConte, 1854
Terrapene	American Box Turtles	Merrem, 1820
Terapene ornata	Ornate Box Turtle	(Agassiz, 1857)
Terrapene ornata luteola (SW)	Desert Box Turtle	Smith and Ramsey, 1952

References

Websites Reptiles and Amphibians of Arizona Southwestern Center for Herpetological Research Society for the Study of Amphibians and Reptiles North American Species Names Database Books Southwest Herps Brennan, Thomas C., and Andrew T. Holycross. Amphibians and Reptiles in Arizona. Arizona Game and Fish Department, 2006. Degenhardt, William G., Charles W. Painter, & Andrew H. Price. Amphibians and Reptiles of New Mexico. University of New Mexico Press, 1996. Samuel M. McGinnis and Robert C. Stebbins. Peterson Field Guide to Western Reptiles & Amphibians. 4th Edition. Houghton Mifflin Harcourt Publishing Company, 2018. Murphy, John C. Arizona's Amphibians & Reptiles: A Natural History and Field Guide. Book Services, 2018. Stebbins, Robert C. A Field Guide to Western Reptiles and Amphibians. 3rd Edition. Houghton Mifflin Company, 2003. Amphibians Bartlett, R. D. & Patricia P. Bartlett. Guide and Reference to the Amphibians of Western North America (North of Mexico) and Hawaii. University Press of Florida, 2009. Dodd, C. Kenneth. Frogs of the United States and Canada, 2-volumes. Johns Hopkins University Press, 2013. Elliott, Lang, Carl Gerhardt, and Carlos Davidson. Frogs and Toads of North America, a Comprehensive Guide to their Identification, Behavior, and Calls. Houghton Mifflin Harcourt, 2009. Snakes Bartlett, R. D. & Patricia P. Bartlett. Guide and Reference to the Snakes of Western North America (North of Mexico) and Hawaii. University Press of Florida, 2009. Ernst, Carl H., Evelyn M. Ernst, & Robert M. Corker. Snakes of the United States and Canada. Smithsonian Institution Press, 2003. Ernst, Carl H. and Evelyn M. Ernst. Venomous Reptiles of the United States, Canada, and Northern Mexico: Heloderma, Micruroides, Micrurus, Pelamis, Agkistrodon, Sistrurus (Volumes 1 & 2) Johns Hopkins University Press. 2011 Lizards Bartlett, R. D. & Patricia P. Bartlett. Guide and Reference to the Turtles and Lizards of Western North America (North of Mexico) and Hawaii. University Press of Florida, 2009. Robert L. Bezy. Night Lizards: Field Memoirs and a Summary of the Xantusiidae. ECO Herpetological Publishing & Distribution. 2019. Jones, Lawrence, Rob Lovich, editors. Lizards of the American Southwest: A Photographic Field Guide. Rio Nuevo Publishers, 2009. Sherbrooke, Wade C. Introduction to Horned Lizards of North America. University of California Press, 2003. Turtles Bartlett, R. D. & Patricia P. Bartlett. Guide and Reference to the Turtles and Lizards of Western North America (North of Mexico) and Hawaii. University Press of Florida, 2009. Carr, Archie. Handbook of Turtles: The Turtles of the United States, Canada, and Baja California. Cornell University Press, 1969. Ernst, Carl H., Roger W. Barbour, & Jeffrey E. Lovich. Turtles of the United States and Canada. Smithsonian Institution 1994. (2nd Edition published 2009)