|Turtle skeletal Vocabulary
When we talk about turtles, we will use many unique terms to describe diagnostic differences between them. Most of these terms are used to describe different bones that form the shell of the turtle. Below are several diagrams that list these terms, learning these terms will help you understand the information that follows.
Terminology for the bones that underlie the scutes
Pleurodira vs. Cryptodira
There are two major divisions within the order Testudines: the Pleurodira and the Cryptodira. The pleurodires are called “side neck turtles”, these animals retract their heads into their shells sideways rather than straight back as seen in cryptodires. This group is often considered the more plesiomorphic condition. The cryptodires are the more familiar “hinge-neck” turtles.
The two also differ in how their jaw adductor muscles attach to their skulls
In Pleurodira the adductor muscle passes over the pterygoid and the otic capsule (c).
In cryptodira the adductor muscle passes over only the otic capsule (d).
The pelvic girdles also differ in how they attach to the plastron.
Pleurodira have a pelvic girdle fused to the plastron.
Cryptodira have an articulated pelvic girdle.
Class Reptilia, Order Testudines, Gigaorder Casichelydia, Megaorder Pleurodira, Family PELOMEDUSIDAE, Subfamily Podocnemidinae, Podocnemis sp., Common Name: Amazon River Turtle
This juvenile Podocnemis serves as a representative for Pelomedusidae, one of the two families of side-necked turtles. Pelomedusidae contains 5 genera and approximately 25 species which are distributed throughout northern South America, southern and central Africa, Madagascar and the Seychelles. Two subfamilies are generally recognized: Podocnemidinae and Pelomedusinae. The genus Podocnemis includes 6 species of neotropical riverine turtles. The largest of these species, P. expansa, reaches a maximum carapace length of over 1 m. Notice the webbed feet and flattened carapace, features that facilitate swimming in these aquatic turtles.
1. What is the Megaorder of this turtle?
2. How will you identify this animal?
Class Reptilia, Order Testudines, Gigaorder Casichelydia, Megaorder Pleurodira, Family CHELIDAE, Subfamily Chelinae, Chelodina siebenrocki, Common Name: Siebenrock's Side-Necked Turtle
In this skeleton of Chelodina siebenrocki, note in particular that the pelvic girdle is fused to the plastron. This is typical of pleurodires and unlike the condition seen in cryptodires. As in all chelids, the quadratojugal and mesoplastra are absent. Note that the cervical vertebrae are longer than those beneath the carapace in these long-necked chelids. As in all pleurodires, the neck is retracted laterally in Chelodina, with the greatest flexion occurring between the 5th and 6th cervical vertebrae. As in all other extant turtles, the jaws of Chelodina are toothless and are modified as sharp shearing beaks.
1. What three characteristics are used to identify this megaorder?
Class Reptilia, Order Testudines, Gigaorder Casichelydia, Megaorder Pleurodira, Family CHELIDAE, Subfamily Chelinae, Chelus fimbriatus, Common Name: Matamata
The family Chelidae includes 10 genera and approximately 40 species of side-necked turtles from South America, Australia and New Guinea. Chelus is a monotypic genus distributed throughout northern South America. This is a large aquatic turtle, reaching a maximum carapace length of about 45 cm. Note the broad, flattened head, the tubular, snorkel-like proboscis, and the cutaneous fringes on the neck and chin. The matamata inhabits slow-moving blackwater streams, muddy lakes, oxbows and swamps, remaining at relatively shallow depths to facilitate breathing. Chelus fimbriatus is a classic 'sit and wait' predator; it sits motionless on the bottom of streams and swamps, waiting for fish to approach within striking distance. The rough, sculptured carapace is typically coated with algae, providing the matamata with excellent camouflage.
1. What is the range of this animal?
2. What is the predatory behavior of this animal?
Class Reptilia, Order Testudines, Gigaorder Casichelydia, Megaorder Cryptodira, Family CHELYDRIDAE, Chelydra serpentine, Common Name: Snapping Turtle
(Local.) The snapping turtle is our largest freshwater turtle. Adults can reach a carapace length of 49 cm and weigh up to 34 kg. Note the strongly serrated posterior margin of the carapace. Three parallel ridges run along the length of the carapace (although these are more pronounced in juveniles than in adults). The tail is nearly as long as the carapace and has a mid-dorsal row of large, keel-like scales. Eggs are usually deposited in May or June. Hatching generally occurs between mid-August and early October, but neonates occasionally overwinter in their nests. Chelydra has temperature-dependent sex determination (TSD). Snapping turtles are omnivorous, eating nearly anything they can fit into their mouths. Included in their diet are fish, crayfish, frogs, earthworms, freshwater sponges, salamanders, turtles, snakes, ducks, rats and algae.
The plastron, the bottom shell of the turtle, of this family is highly reduced compared to other turtles. The connections between the plastron and the carapace, the top part of the shell, is also reduced to a thin bridge.
Snapping turtle plastron
Blandings turtle plastron
1. Is this animal local?
2. How will you distinguish this snapping turtle from the alligator snapper?
3. What characteristics of the plastron are used to identify Chelydridea?
Class Reptilia, Order Testudines, Gigaorder Casichelydia, Megaorder Cryptodira, Family CHELYDRIDA, Macroclemys teminckii Common Name: Alligator Snapping Turtle
Macroclemys teminckii is the largest North American freshwater turtle, reaching a carapace length of up to 80 cm and a weight of up to 113 kg. It is distributed throughout the Mississippi River Valley from Kansas, Iowa and Illinois southward to the Gulf of Mexico, and along the coastal plain from southeastern Georgia and northern Florida to eastern Texas. Alligator snappers inhabit deep rivers, streams, lakes, swamps, ponds, canals and oxbows. The dark, sculptured carapace has three prominent keels and is strongly serrated posteriorly. The head is enormous and the upper jaw is strongly hooked. (Be sure to examine the adult skull on display!) A fleshy worm-like appendage on the tongue is used to lure prey into the mouth. Cool video: http://youtu.be/sU6LyFfbcZE The diet of Macroclemys includes fish, crayfish, salamanders, crabs, raccoons, clams, turtles, acorns and palmetto fruit.
1. What predatory strategy does this animal use?
2. What is the range of this animal?
Class Reptilia, Order Testudines, Gigaorder Casichelydia, Megaorder Cryptodira, Superfamily Chelonioidea, Family DERMOCHELYIDAE, Dermochelys coriacea, Common Name: Leatherback Sea Turtle
(Local.) Dermochelys coriacea is the largest extant species of turtle, reaching a carapace length of up to 244 cm and a weight of up to 867 kg. This enormous sea turtle has perhaps the widest geographic distribution of any living reptile, inhabiting the waters of the Pacific, Atlantic and Indian oceans. Dermochelys is unique among living turtles in that the carapace is composed of thousands of polygonal osteoderms embedded in their leathery skin. Seven longitudinal keels are present on the carapace, and four are present on the plastron. Leatherbacks feed largely on jellyfish. Examine the esophageal segments on display. The entire esophagus is lined with posteriorly-pointing spines that help to prevent prey from escaping. Also examine the humerus of Dermochelys and compare it with that of Geochelone. Note the large deltopectoral crest, located far down the shaft of the humerus; the distal position and large surface area of the DPC allows the leatherback to move its huge, paddlelike forelimbs through the water with tremendous force. Dermochelys inhabits seas as cold as 6_ C, but in these cold environments, they can maintain body temperatures 18_ C or more above ambient water temperature.
1. How big does this animal get?
2. How does the formation of this animal’s carapace differ from other turtles?
3. Draw the lining of this animal’s esophagus, what is the function of this strange structure?
4. This animals phalanges are unique, how so?
Class Reptilia, Order Testudines, Gigaorder Casichelydia, Megaorder Cryptodira, Superfamily Chelonioidea, Family CHELONIIDAE, Caretta caretta, Common Name: Loggerhead Sea Turtle
(Local.) Caretta caretta is the largest extant species of hard-shelled turtle, reaching a maximum carapace length of 213 cm and a maximum weight of over 500 kg. Among living turtles, only Dermochelys grows larger. The loggerhead is found throughout the Atlantic, Pacific and Indian Oceans. Note the large head and massive jaws. Caretta is omnivorous, and their diet includes sponges, jellyfish, squid, clams, oysters, horseshoe crabs, young loggerhead turtles, vascular plants, algae, seahorses, pufferfish and mackerel. Although listed as a threatened species, Caretta caretta remains the most abundant sea turtle in North American waters.
1. Is this the world’s largest turtle?
2. What is this animals range?
3. How will you identify this sea turtle from the others?
Class Reptilia, Order Testudines, Gigaorder Casichelydia, Megaorder Cryptodira, Superfamily Chelonioidea, Family CHELONIIDAE, Lepidochelys kempii, Common Name: Kemp's Ridley Sea Turtle
(Local.) Lepidochelys kempii is a small sea turtle, reaching a carapace length of only about 72 cm. Adults of this species are rarely found outside the Gulf of Mexico, but juveniles migrate throughout the Atlantic Ocean in the Northern Hemisphere. Almost all nesting in this species occurs on a single beach near Rancho Nuevo in Tamaulipas, Mexico. Generally all females emerge to oviposit on the same day. During one of these arribadas (Spanish for 'arrivals') in 1947, 42,000 females came ashore to nest on a single day. In 1988, less than 200 females came ashore to nest during the largest arribada. Fishing, nest robbing, oil spills and slaughter of nesting females have all contributed to the decline of this species.
1. Where does this animal nest, how does this affect its population viability?
2. How will you identify this sea turtle from the others?
Class Reptilia, Order Testudines, Gigaorder Casichelydia, Megaorder Cryptodira, Superfamily Chelonioidea, Family CHELONIIDAE, Lepidochelys kempii, Common Name: Kemp's Ridley Sea Turtle
In this disarticulated skeleton of Lepidochelys kempii, note that the temporal region of the skull is completely roofed over with bone. This is typical for sea turtles, but rather unlike the condition seen in most other turtles in which there is extensive emargination of the posterior temporal region. Note also the peripheral fenestrae between the relatively well-developed ribs. The carapace and plastron are connected only by ligaments, and neither is hinged. Perhaps the most distinctive feature of the sea turtle's skeleton is its highly modified forelimbs that function as flippers to propel the turtle through the water. Note the elongated digits. Also notice the position of the deltopectoral crest, located far down the shaft of the humerus; the distal position of this muscle insertion point allows the sea turtle to move its paddlelike forelimbs through the water with great force.
1. How is this turtles skull unique from other non sea turtles?
2. Draw the dermal ribs of this animal and identify the peripheral fenestrae?
3. Draw the humerus of this turtle and identify the deltopectoral crest, what is the function of the odd shape of this crest?
Class Reptilia, Order Testudines, Gigaorder Casichelydia, Megaorder Cryptodira, Superfamily Chelonioidea, Family CHELONIIDAE, Chelonia mydas, Common Name: Green Turtle
(Local.) Chelonia mydas is a medium to large sea turtle, reaching a maximum carapace length of 153 cm. It is found in the Atlantic, Pacific and Indian Oceans, but is distributed primarily throughout the tropics. Green turtles are occasionally found off the coast of Massachusetts, where they graze on sea grasses and other aquatic vegetation. The broad, low, heart-shaped carapace lacks a vertebral keel and is only slightly serrated posteriorly. The carapacial scutes are typically olive to brown in color. The common name of this species is derived from the greenish color of its body fat. Chelonia mydas is the only sea turtle that subsists mainly on plant material (although juveniles are apparently somewhat more carnivorous than adults). It is also the only species of sea turtle that comes ashore regularly to bask. The commercial exploitation of this species is extensive. Its eggs are harvested for food in third-world countries where protein is scarce and its flesh is used to make turtle soup, the demand for which has supported commercial fisheries since the 17th century. This exploitation has resulted is significant population declines worldwide.
1. How will you identify this turtle from the other sea turtles?
2. Where did this animal get its common name?
3. What is its main source of food?
4. What factors have led to this turtles decline?
Class Reptilia, Order Testudines, Gigaorder Casichelydia, Megaorder Cryptodira, Superfamily Chelonioidea, Family CHELONIIDAE, Eretmochelys imbricate, Common Name: Hawksbill Sea Turtle
(Local.) Eretmochelys imbricata is a small to medium-sized sea turtle, growing to a maximum carapace length of 114 cm. In juveniles, the carapacial scutes, the scales on the carapace, are strongly overlapping (hence the specific name). The snout is elongated and narrow (hence the common name). The hawksbill is predominantly tropical, but it is known to range throughout the Atlantic, Pacific and Indian Oceans. It is only very rarely seen in the coastal waters off of Massachusetts. Eretmochelys is omnivorous, but seems to prefer invertebrates, especially sponges. The hawksbill's translucent carapacial scutes are sold commercially as 'tortoiseshell'. Usually the turtles are killed before their scutes are removed. Apparently there is some evidence suggesting that if the scutes are removed 'carefully' from live animals, there is some possibility that they may be regenerated. However, given that the scutes are most often removed through the application of heat (e.g., roasting the turtle's carapace over an open fire), the chances of a turtle surviving the process would seem to be rather slim.
1. How did this animal get its specific name, common name?
2. What is the commercial fate of this animal’s scutes?
3. Why can they not be harvested from live animals?
Class Reptilia, Order Testudines, Gigaorder Casichelydia, Megaorder Cryptodira, Superfamily Trionychoidea, Family KINOSTERNIDAE, Subfamily Kinosterninae, Sternotherus odoratus , Common Name: Common Musk Turtle or Stinkpot
(Local.) The stinkpot is our only local representative of the family Kinosternidae. This family includes 4 genera and 23 species that are distributed from southern Canada to central South America. Sternotherus odoratus is a small kinosternid with two prominent light stripes on the side of the head. The carapace is highly arched, and juveniles have a prominent mid-dorsal keel. The plastron is small and has an indistinct hinge between the pectoral and abdominal scutes. Sternotherus odoratus is distributed throughout the eastern United States and southern Ontario. Although stinkpots are often abundant, they are nocturnal and aquatic, and are therefore seldom seen. These small turtles may occur in almost any waterway within their range that has slow currents and a soft bottom (e.g., ponds, lakes, swamps, bayous, etc.). The common name 'stinkpot' derives from the tendency of this species to void the contents of their musk glands when harassed. While only a few milligrams of musk are released at a time, the resulting stench is powerful enough to deter many would-be predators.
1. What features will you use to distinguish this animal?
2. Where is the hinge located in this animal’s plastron?
3. Where did this animal get its common name?
4. What is the distribution of this animal, when are you likely to see it?
Class Reptilia, Order Testudines, Gigaorder Casichelydia, Megaorder Cryptodira, Superfamily Trionychoidea, Family CARETTOCHELYIDAE, Carettochelys insculpta , Common Name: Pig-Nosed Turtle
Carettochelys insculpta is the only extant species contained within the family Carettochelyidae. Carettochelys is a freshwater turtle, inhabiting rivers, streams, lakes and lagoons in New Guinea and extreme northern Australia. As in trionychids, the carapace has no keratinous scutes, but is instead covered with soft skin. Also like trionychids, this species has a fleshy proboscis at the tip of the snout (giving it a somewhat 'pig-nosed' appearance). As in sea turtles, the limbs have been modified into elongates flippers, and propulsion through the water is driven by synchronous movements of the forelimbs. Carettochelys reaches a carapace length of approximately 70 cm, and feeds on aquatic plants, fish, snails and the fruits of figs that have dropped into the water.
1. How many other extant genera are within this family?
2. What features are missing from this animal’s carapace and plastron?
3. Draw the nose of this animal?
Class Reptilia, Order Testudines, Gigaorder Casichelydia, Megaorder Cryptodira, Superfamily Trionychoidea, Family TRIONYCHIDAE, Subfamily Trionychinae, Apalone spinifera, Common Name: Spiny Softshell Turtle
The family Trionychidae contains 14 genera and approximately 25 species of soft-shelled turtles that are distributed throughout parts of North America, Africa and Asia. These strictly aquatic turtles have dorsoventrally flattened carapaces that lack horny scutes, but are covered instead with a leathery skin. There is also a reduction of the bony elements of the carapace. The snout bears a fleshy proboscis and the jaws are covered with fleshy lips rather than keratinous beaks. The seven recognized subspecies of Apalone spinifera have a complex distribution in the United States, southeastern Canada, and northern Mexico. A nearby disjunct population of Apalone s. spinifera occurs in Lake Champlain and the lower reaches of the Ottawa River in Quebec and Ontario. Females of this species may reach a carapace length of up to 54 cm and a weight of up to 11.7 kg. Males are considerably smaller. Note the small spiny projections along the anterior edge of the carapace that give this species its common name. These ill-tempered turtles are predominantly carnivorous, commonly eating insect larvae, crayfish and fish.
1. What features are missing from this family’s skeletal carapace?
2. What features are unique to this turtles face?
Class Reptilia, Order Testudines, Gigaorder Casichelydia, Megaorder Cryptodira, Superfamily Trionychoidea, Family TRIONYCHIDAE, Subfamily Trionychinae, Pelodiscus sinensis, Common Name: Chinese Softshell Turtle
In this skeleton of Pelodiscus sinensis, note the reduction of the bony elements of the carapace that is typical of trionychids. The peripheral bones are absent, so the distal ends of the ribs project freely beyond the edge of the costal bones. The pygal bone is also absent in softshells. Notice that the carapacial bones are finely pitted. There is extensive emargination of the temporal region of the skull. Note also the mid-ventral separation between the hyoplastra and the hypoplastra.
1. What bone is absent in softshell turtles?
2. What features are unique to this animal’s plastron?
3. How does this animal’s skull compare to the sea turtles?
Class Reptilia, Order Testudines, Gigaorder Casichelydia, Megaorder Cryptodira, Superfamily Testudinoidea, Family EMYDIDAE, Subfamily Emydinae, Clemmys guttata, Common Name: Spotted Turtle
(Local.) Clemmys guttata ranges from southern Ontario, Quebec and Maine southward along the Atlantic Coastal Plain and Piedmont to northern Florida, and westward through New York, Pennsylvania, Ohio, Indiana and Michigan to northeastern Illinois. Spotted turtles reach a maximum carapace length of about 12 cm. The carapace is black with small yellow spots. The spots often fade with age, however, and older specimens may be spotless or nearly so. Males have tan chins, brown eyes, and slightly concave plastra. Females have yellow chins, orange eyes, and flat or convex plastra. Unlike other species of Clemmys, female C. guttata are generally larger than males. This species inhabits swamps, bogs, wet meadows and marshy pastures. Breeding occurs in the spring and oviposition usually occurs between May and July. Clutches are small, averaging only 3-4 eggs. Habitat destruction and collection of animals for the pet trade present serious threats to the survival of this species.
1. What is the most obvious feature of this animal?
2. What is the distribution of this animal?
3. How can you identify the two sexes?
Class Reptilia, Order Testudines, Gigaorder Casichelydia, Megaorder Cryptodira, Superfamily Testudinoidea, Family EMYDIDAE, Subfamily Emydinae, Glyptemys muhlenbergii, Common Name: Bog Turtle
(Local.) DO NOT REMOVE. Glyptemys muhlenbergii is a small turtle, reaching a maximum carapace length of only about 11 cm. The geographic distribution of this species is discontinuous and confined to the eastern United States. Western Massachusetts lies at the northeastern extreme of its range. The large, bright blotch on the side of the head is distinctive. Bog turtles live in spring-fed Sphagnum bogs and marshy meadows. Mating occurs in the spring, and females deposit clutches of 1-6 eggs between May and July. Clemmys muhlenbergii is omnivorous; included in its diet are insects, earthworms, salamanders, berries and skunk cabbage. In Massachusetts, this species is restricted to a few localities in Berkshire County.
1. What is the distribution of this animal, where can you find it locally?
2. How will you identify it?
Class Reptilia, Order Testudines, Gigaorder Casichelydia, Megaorder Cryptodira, Superfamily Testudinoidea, Family EMYDIDAE, Subfamily Emydinae, Glyptemys insculpta, Common Name: Wood Turtle
(Local.) The wood turtle reaches a carapace length of up to 22 cm in our area. This species is distributed from Nova Scotia and New Brunswick southward to Virginia, and westward through southern Quebec, southern Ontario and New York to northern Michigan, Wisconsin, eastern Minnesota and northeastern Iowa. The carapace is keeled and heavily sculptured. Concentric growth annuli form irregular pyramids on each carapacial scute. The carapacial scutes are tan, grayish brown or brown. The hingeless plastron is yellow with an oblong black blotch on each scute. The skin is dark brown dorsally and yellow, orange or red ventrally. Males have a concave plastron and females have a flat plastron. Wood turtles hibernate underwater during the winter. In some areas, groups of up to 70 turtles have been discovered in communal hibernacula. During the spring, summer and fall wood turtles are predominantly terrestrial, although they may spend their nights in water. Mating occurs in the fall or spring and eggs are usually deposited in May or June. Only a single clutch of about 7 eggs is laid per year, but females may not nest every year. Clemmys insculpta exhibits a peculiar feeding behavior called 'worm stomping'. They pound their front feet against the ground to simulate the vibrations caused by falling raindrops. This sound draws earthworms to the surface, at which point they are eaten by the turtles. Here is a rather funny video of a worm grunting competition: http://www.youtube.com/watch?v=FK-Oo7NwPiQ
1. Describe this animals carapace, how will it help you identify this animal?
2. How do these animals overwinter?
3. How do these animals find food?
Class Reptilia, Order Testudines, Gigaorder Casichelydia, Megaorder Cryptodira, Superfamily Testudinoidea, Family EMYDIDAE, Subfamily Emydinae, Chrysemys picta, Common Name: Painted Turtle
(Local.) Chrysemys picta has an extremely wide distribution across North America, and in the United States, it is completely absent only in Florida, Nevada and California. We have two subspecies of Chrysemys picta in Massachusetts; the eastern painted turtle (Chrysemys p. picta) and the midland painted turtle (Chrysemys p. marginata). In Chrysemys p. picta, the large carapacial scutes are arranged in straight rows across the back, while in Chrysemys p. marginata, these scutes are arranged in a staggered pattern. Painted turtles are relatively small (up to 25 cm maximum carapace length) aquatic turtles that frequently haul themselves out of the water to bask. Ponds, marshes and lakes with a soft bottom, basking sites and aquatic vegetation are their preferred habitats. Male painted turtles are distinguished by their elongated foreclaws and their long, thick tails. Females are larger than males in all shell dimensions. Chrysemys picta is omnivorous; most species of plants and animals, living or dead, will be eaten if the opportunity arises. While a great deal of foraging occurs along the bottom, painted turtles also exhibit a surface-skimming feeding behavior called neustophagia. Courtship is elaborate in painted turtles, and nesting usually occurs between late May and mid-July. Sex determination is temperature-dependent.
1. How can you tell between the two subspecies, which subspecies do we have in this class?
2. How can you tell between the sexes?
3. How do the males of this species court the females?
4. These animals have a strange feeding behavior, what is it?
Class Reptilia, Order Testudines, Gigaorder Casichelydia, Megaorder Cryptodira, Superfamily Testudinoidea, Family EMYDIDAE, Subfamily Emydinae, Malaclemys terrapin, Common Name: Diamondback Terrapin
(Local.) The diamondback terrapin is a small to medium-sized turtle, reaching a maximum carapace length of about 23 cm. This species inhabits estuaries and salt marshes along the Atlantic and Gulf coasts from Cape Cod to Texas. The northern diamondback terrapin, Malaclemys t. terrapin, ranges from Cape Cod to Cape Hatteras. The carapacial scutes vary from black to light brown in color and bear distinct concentric rings. The hingeless plastron is orangish to greenish gray. The jaws are light in color and females have broad crushing plates on the jaws. Adult females are much larger than males. The feet are strongly webbed and the hind feet are large. Diamondback terrapins feed on periwinkles, crabs, mussels, and marine annelids as well as some plant material. Mating occurs during the spring and females usually deposit clutches of 4-18 eggs in June or July. The flesh of this species makes excellent soup stock, and this nearly brought about the extirpation of many populations near coastal metropolitan areas during the 1920s. Most of these populations have since recovered.
1. What environment is this animal found in?
2. How will this animal’s carapace help you identify it?
3. What does this animal eat?
4. What factors have led to this animals decline?
Class Reptilia, Order Testudines, Gigaorder Casichelydia, Megaorder Cryptodira, Superfamily Testudinoidea, Family EMYDIDAE, Subfamily Emydinae, Terrapene carolina Common Box Turtle
(Local.) Terrapene carolina is a small terrestrial emydid with a hinged plastron and a keeled, high-domed carapace. Six extant subspecies are recognized, ranging from Maine to the Yucatán Peninsula. The eastern box turtle, Terrapene c. carolina, ranges from southern Maine south to Georgia and west to Michigan, Illinois, Tennessee and northern Alabama. This subspecies reaches a maximum carapace length of about 20 cm. In males, the eyes are usually red and the posterior lobe of the plastron is concave. In females, the eyes are usually yellowish brown and the posterior lobe of the plastron is flat or slightly convex. These turtles burrowing into the ground to hibernate. They dig deeper as the soil temperature drops: to as deep as 60 cm by the end of winter. Courtship and mating typically begin in May, and nesting may continue through July. Females may lay fertile eggs for up to 4 years from a single successful mating. These turtles rank among the longest-lived vertebrates. One individual was reported to have lived in the wild for 138 years. The well-developed plastral hinge1 of Terrapene allows these turtles to close themselves tightly into their shells (hence their common name).
Plastral Hinge – A hinge on the plastron allows the animal to fold it’s plastron and completely close itself off.
1. How will you identify this turtle?
2. How can you tell the difference between the sexes in this turtle?
3. How do these animals overwinter?
4. How long do these turtles live?
5. What feature of the plastron gives this turtle its common name?
Class Reptilia, Order Testudines, Gigaorder Casichelydia, Megaorder Cryptodira, Superfamily Testudinoidea, Family EMYDIDAE, Subfamily Emydinae, Emydoidea blandingii, Common Name: Blanding's Turtle
(Local.) Emydoidea blandingii is a medium-sized turtle, reaching a maximum carapace length of about 27 cm. This species ranges from southwestern Quebec and southern Ontario south through the Great Lakes region and west to Iowa and Nebraska. Disjunct populations also occur in southeastern New York, eastern Massachusetts through southern Maine, and on Nova Scotia. The carapace is black with light spots or streaks and is neither keeled nor serrated. The plastron is hinged and is connected to the carapace only by ligaments. Emydoidea is highly aquatic and prefers shallow lakes, ponds and marshes with abundant aquatic vegetation and basking sites. These turtles hibernate underwater, burrowing into the organic substrate at the bottom of ponds. They remain somewhat active during the winter, however, and are occasionally seen swimming beneath ice.
1. How will you identify this turtle from the others?
2. How does the connection between this turtle’s plastron and carapace differ from other Emydidae turtles?
3. How do these turtles over winter?
4. What features of this turtle are modified for an aquatic lifestyle?
Class Reptilia, Order Testudines, Gigaorder Casichelydia, Megaorder Cryptodira, Superfamily Testudinoidea, Family EMYDIDAE, Subfamily Emydinae, Pseudemys rubriventris Red-Bellied Turtle
(Local.) Pseudemys rubriventris is a large pond turtle, reaching a maximum carapace length of 40 cm. This species ranges along the Atlantic Coastal Plain from central New Jersey south to northeastern North Carolina. Relict populations also occur in Plymouth County, Massachusetts. These relict populations were described as representing a distinct subspecies (Pseudemys r. bangsi) by Harold Babcock in 1937, but subsequent workers have demonstrated that subspecific recognition of these populations is unwarranted. However, despite the morphological and molecular evidence suggesting that Pseudemys rubriventris bangsi is not a valid subspecies, the U.S. Fish & Wildlife Service continues to list the Plymouth red-bellied turtle as a federally endangered species. Only about 200 of these turtles remain in Massachusetts. Archaeological evidence suggests that Native Americans frequently ate turtles from these populations.
1. This turtle has a turbulent past, why is it wrong that these turtles are listed as an endangered subspecies?
2. How will you identify this species?
Class Reptilia, Order Testudines, Gigaorder Casichelydia, Megaorder Cryptodira, Superfamily Testudinoidea, Family TESTUDINIDAE, Gopherus polyphemus Gopher Tortoise
Gopherus polyphemus is a relatively large tortoise, reaching a maximum carapace length of 38 cm. This species ranges from southern South Carolina south through peninsular Florida and west to southeastern Louisiana. The dark brown to grayish-black carapace is oblong in shape and lacks a keel. The plastra of males are more concave and have larger gular projections than those of females. Note the elaphantine hind feet and shovellike forefeet. Gopher tortoises dig long burrows that may reach 15 m in length. An enlarged chamber is usually present at the end of the burrow, in which the tortoise sleeps and can turn around. A wide variety of animals utilize gopher tortoise burrows as temporary shelter or as permanent homes. Opossums, skunks, coyotes, burrowing owls, snakes, amphisbaenians, lizards, frogs and spiders are but a few of the animals that have been found living with tortoises in these burrows. Indigo snakes (Drymarchon) are often called 'gopher snakes' because of the propensity for taking refuge in gopher tortoise burrows. Gopher tortoises generally mate in the spring and females deposit clutches of 1-25 eggs between late April and mid-July. Eggs are usually deposited near the entrance to the tortoise's burrow. Habitat destruction poses the most serious threat to this species.
1. What features of tortoises will help you distinguish them from terrestrial Emydidae?
2. How will you identify this particular tortoise?
3. Where did this turtle get its common name?
4. What other reptile got its common name from this turtle’s home?
5. Describe this turtle’s burrow, how deep is it, where does it sleep, where does it lay its eggs?
Class Reptilia, Order Testudines, Gigaorder Casichelydia, Megaorder Cryptodira, Superfamily Testudinoidea, Family TESTUDINIDAE, Malacochersus tornieri Pancake Tortoise
Malacochersus tornieri is a small East African tortoise, reaching a maximum carapace length of about 17 cm. The hingeless carapace has no keel and is dorsoventrally flattened. Adult pancake tortoises retain fenestrae between the bones of the carapace, and this results in a relatively pliable carapace, allowing these tortoises to wedge themselves into narrow crevices under rocks to avoid predators. Mating occurs in January and February, and females deposit clutches consisting of a single egg (although several clutches may be laid each year). Grasses constitute the bulk of the pancake tortoise's diet, although other vegetation and fruits may be eaten.
1. What features of this animal’s carapace give this turtle its common name? How do these features affect this animal’s behavior?
2. What does this animal eat?
3. What is the range of this turtle?
Class Reptilia, Order Testudines, Gigaorder Casichelydia, Megaorder Cryptodira, Superfamily Testudinoidea, Family TESTUDINIDAE, Manouria emys Asian Brown Tortoise
Manouria emys is the largest species of tortoise in Asia, reaching a maximum carapace length of 60 cm. In this disarticulated skeleton of Manouria, note that the temporal region of the skull is widely emarginated posteriorly. Compare this to the condition seen in the sea turtles Lepidochelys and Dermochelys. Note also that the ribs are greatly reduced. The carapace and plastron are firmly sutured at the bridge (at least they were before they were sawed apart in this specimen), and neither the carapace nor the plastron are hinged. Verify that Manouria, like all other tortoises, lacks mesoplastral bones. Also typical for the family Testudinidae are the stout, columnar hind limbs, resembling those of an elephant.
1. How does this turtle’s skull compare to sea turtle’s?
2. What plastral bones are missing in this turtle?
3. Does this turtle’s plastron have hinges?
4. What is the condition of this turtle’s ribs?
Class Reptilia, Order Testudines, Gigaorder Casichelydia, Megaorder Cryptodira, Superfamily Testudinoidea, Family TESTUDINIDAE, Kinixys homeana Home's Hinge-Back Tortoise
Kinixys is the only genus of extant turtles in which there is a movable hinge within the carapace. This hinge lies between the 4th and 5th costals and the 7th and 8th peripherals in adults and allows the posterior portion of the carapace to be lowered over the hindquarters. The plastron is hingeless, however. This genus contains 4 species and all are restricted to Africa. K. homeana ranges in West Africa from Liberia and Ivory Coast eastward to Zaire. The elongated carapace of this forest-dwelling species may reach lengths of up to 21 cm. The carapaces of juveniles are somewhat flattened and lack a hinge.
1. This turtle has a hinge in a unique place, where is it?
2. What is the range of this animal?