(Linnaeus, 1758)
European pond turtle
Recognition
Emys orbicularis has an oval (to 23 cm), moderately depressed carapace which is widest behind the middle, and unserrated. A medial keel is present on juveniles, but, as the carapace grows, this becomes progressively lower until it may be lost. Hatchlings may also possess a pair of low lateral keels. Vertebrals are broader than long, with the 5th the widest. The underlying neurals are hexagonal and shortest sided anteriorly. The carapace ranges in color from olive brown to brown or, most often, black, patterned with numerous yellow radiations or dots. The plastron is large, has a movable hinge between the pectoral and abdominal scutes (between the underlying hyo- and hypoplastral bones), lacks buttresses in adults, and has only a ligamentous connection with the carapace. The hinge cannot completely close the shell in adults, but is more flexible in the young. Axillary and inguinal scutes are usually absent, but, if present, are small and poorly developed. The entoplastron is crossed by the humero-pectoral seam. The plastral formula usually is: an > abd > pect > gul > fem > hum. The plastron varies from totally black or dark brown to yellow with each scute black bordered. The skull has a complete temporal arch. Its frontal bone does not enter the orbit border, and the lower end of the jugal extends inward along the posterior edge of the maxilla to touch the pterygoid. The posterior palatine foramen is large. Triturating surfaces are narrow, unserrated, and ridgeless; the upper jaw is medially notched. Dorsal skin of the head is not divided into scales. Limbs are covered with small to medium-sized scales, not large ones. The toes are webbed, and the tail is relatively long. Skin of the head, neck, limbs, and tail is yellow-brown to black, and may contain yellow radiations or spots. The iris color of males varies per region—from red, brownish-yellow and yellow to pure white; eyes of females generally are yellow, occasionally white.
Matthey (1931) reported the diploid chromosome number to be 50.
Males have thicker tails than females with the vent closer to the tip, concave plastra, and their claws are distinctly curved. Females have flat to even convex plastra and straight claws (Fritz and Günther, 1996).
Distribution
Emys orbicularis ranges from the Caspian Sea in Iran and Azerbaijan westward through Turkey and eastern Europe to the Baltic states of Latvia and Lithuania, and to central Germany. It also occurs in Greece, Italy, southern and central France, Spain and Portugal; on Sicily, Corsica, Sardinia, the Balearic Islands, several Adriatic, Ionian, and Aegean Islands; and in northwestern Africa in Morocco, Algeria and Tunisia. A record from Israel (Fritz, 1989b) probably is in error (Fritz, 1993a). Formerly the range was more extensive, as postglacial remains have been found in Sweden, Denmark, the Netherlands, England (Loveridge and Williams, 1957), and Estonia (Fritz, 1996).
Geographic Variation
Fritz has, in several papers published since 1989, described or resurrected 13 subspecies of Emys orbicularis, which he placed in five subspecies groups (Fritz, 1995a, 1996; modified by Fritz, 1998).
The "orbicularis -group" currently consists of three subspecies (Fritz, 1998)—Emys o. orbicularis, E. o. colchica, and E. o. eiselti (but see Fritz et al., 1998 for a discussion of E. o. colchica populations from eastern Turkey and the adjacent western Caucasus). European pond turtles from the "orbicularis -group" have small to large, dark shells, relatively short interanal seams, and their soft parts show much reduced sexual dimorphism; males have red eyes. The nominate subspecies Emys orbicularis orbicularis (Linnaeus, 1758), the common European pond turtle, is found in central France, and from eastern Europe to the Aral Sea. It has been extirpated in historic times in most of central Europe (Fritz, 1996). The black carapace, to 23 cm, is finely speckled with yellow pigment (orbicularis-type) and the plastron is yellow with large dark blotches or extensive dark pigment on all scutes, generally appearing mostly black. The head pattern varies from unicolored dark to extensively covered with yellow reticulations or spots; the throat is black with small yellow spots (but females from central France may have lighter throats). E. o. colchica Fritz, 1994a, the Colchis pond turtle, was described from the Colchis region of the Caucasus in western Georgia, and from isolated populations in eastern Turkey and the Turkish Black Sea coast. The carapace (to 15 cm) is black with some reduced yellow markings; the plastron is primarily dark. The head has light mottling or scattered yellow spots, and the throat color ranges from black with small yellow spots to smudged-yellow. E. o. colchica is distinguished from E. o. orbicularis by its smaller size and slightly lighter coloration; however, Fritz et al. (1998) state that colchica as it is currently recognized "is best understood as a wastebasket for all populations from eastern Turkey and the Colchis area" and may even include some populations of the nominate subspecies. Fritz et al. (1998) subdivided the European pond turtles from Asiatic Turkey into several geographic groups ("possibly representing evolutionary units") and described the most distinct form as E. o. eiselti Fritz, Baran, Budak and Amthauer, 1998, Eiselt's pond turtle. This small (to 13 cm) subspecies occurs in the northern part of the Amik-Maras rift valley, Turkey, and in part includes Fritz's (1993a, 1996) unnamed "subspecies D". More southerly populations (the "Iskenderun group", Fritz et al., 1998) include both former "subspecies E" and the Orontes River population of former "subspecies D" (see Fritz, 1993a, 1996) and should probably be considered intermediates between E. o. cf. hellenica (sensu Fritz et al., 1998) and E. o. eiselti (Fritz et al., 1998). The plastron of E. o. eiselti is almost entirely black and its throat very dark with only a few yellow spots. This subspecies is separated from all other Emys orbicularis by extremely small gulars and hence a short intergular seam.
Members of the "galloitalica -group" (E. o. galloitalica, E. o. lanzai, and E. o. capolongoi) are characterized by a moderate-sized carapace, a variable dorsal head pattern, a parallel-sided cervical scute, and a shared basic pattern of plastron and foreleg markings; males have a yellow to yellowish-white iris. The subspecies of this group are very similar and difficult to separate; they were described by Fritz (1995a) as one 'megasubspecies'. A mitochondrial DNA study by Lenk et al. (1998) showed that galloitalica and capolongoi genetically are identical to mainland populations from southern France and the Tyrrhenian coast. Fritz (1998), however, states that "clear morphological and ecological differences justify and reinforce the further treatment of galloitalica, lanzai, and capolongoi as 'microsubspecies'". E. o. galloitalica Fritz, 1995a, the Italian pond turtle, ranges from southern France southward on the Italian Peninsula west of the Apennines to the Gulf of Policastro, with an isolated population in the Monte Gargano region at the Adriatic coast. It has a variably-patterned carapace (from the light maculosa-type to the dark orbicularis-type) to 15 (16.5) cm. The plastron is yellow with dark pigmented seams, which may broaden towards the rim; in other individuals the black is reduced to just a few dark spots. Both age-related flavism (in maculosa-type) and—less frequently—melanism (in orbicularis-type) occur. Soft part coloration generally is intermediate between E. o. capolongoi and E. o. lanzai. The iris of both male and female is yellow to yellowish-white; males with pure white irises are also known. E. o. lanzai Fritz, 1995a, the Corsican pond turtle, is found on the island of Corsica. Its 15 cm carapace is slightly darker and larger than the other subspecies of this group. The plastron is yellow with dark pigmentation varying from only along the seams to some dark blotches on the pectorals and humerals, or extensive dark pigment on all scutes; age-related melanism is frequent. Its dark head has small scattered light spots; head and throat coloration is generally darker than in E. o. capolongoi and E. o. galloitalica. The iris of both male and female are yellow to yellowish-white. E. o. lanzai is distinguished from E. o. galloitalica by a longer and (only in males) broader head, and a less variable, darker coloration. E. o. capolongoi Fritz, 1995a, the Sardinian pond turtle, is from the island of Sardinia. Its carapace, to 14.5 cm, is generally quite light-colored, but darker individuals also occur. The plastron has the seams dark near the rim and a few dark spots, but also may be entirely yellow. Head markings and throat coloration are variable; the iris of both male and female is yellow. The Sardinian pond turtle is distinguished from E. o. lanzai by a shorter and more slender head, lighter coloration of plastron and soft parts, and an dorso-medial yellow tail stripe. It is separated from E. o. galloitalica by a generally more uniformly lighter coloration and the ever-present tail stripe; females have narrower heads.
The three mid-sized subspecies in the "occidentalis -group" (E. o. occidentalis, E. o. hispanica, and E. o. fritzjuergenobsti) are characterized by having long intergular scutes and relatively large heads. E. o. occidentalis Fritz, 1993b, the North African pond turtle, is found in Morocco, eastern Algeria and northern Tunisia. It has a dark carapace (to 15 cm), an almost totally dark plastron (but age-related flavism occurs), a black head with yellow vermiculations, and a throat that is either black with yellow spots or yellow with black spots. The iris color of males from the Middle Atlas varies from yellow to whitish. Fritz (1994b) has reported a second distinctly different yellowish pond turtle that was collected near Algiers early in the 20th century, but believed this unnamed form probably extinct. E. o. hispanica Fritz, Keller and Budde, 1996a, the Spanish pond turtle, is found in southwestern Spain and Portugal. Fritz (1996) speculated its range possibly covers the entire Iberian Peninsula except of the east coast, but preliminary results of Cordero and Ayres (1998) suggest that that Galician Emys orbicularis may represent a yet undescribed subspecies or an intergrade population (Adolfo Cordero, pers. comm.). E. o. hispanica reaches 17 cm and has a broad, dark carapace, generally of the orbicularis-type, but the maculosa-type and intermediates are not uncommon. The plastron is yellow, with or without dark seams or dark blotches; old individuals may have entirely yellow plastra (age-related flavism). The head is dark with yellow or brown vermiculations; the throat ranges from yellow to black with yellow spots. Iris color of the male is yellow (or brownish) to white; the female has a yellow to white eye. E. o. hispanica is distinguished from E. o. occidentalis by a longer and broader, parallel-sided cervical, shorter interhumeral seam and lighter coloration. E. o. fritzjuergenobsti Fritz, 1993b, Obst's pond turtle, which occurs in eastern Spain, has a generally light-colored, narrowly elongated carapace (to 15 cm), a yellow plastron, with dark pigment ranging from only on the seams to extensive on some scutes, a dark head with yellow vermiculations, and a yellow throat with or without small dark markings. Male have yellow to brownish-yellow eyes. Obst's pond turtle is separated from E. o. hispanica by a narrower carapace, a longer interfemoral seam, and lighter colors, and from E. o. occidentalis by lighter coloration, and a broader, parallel-sided cervical scute.
Members of the "hellenica -group" (E. o. hellenica, E. o. iberica and E. o. persica) share small to moderate-sized light shells, a relatively large head (some populations show age-related megacephaly), a yellow throat, a relatively short interanal seam, and soft parts showing distinct sexual dichromatism; the iris color of males is variable. E. o. hellenica (Valenciennes, 1832), the Western Turkey pond turtle, ranges from Dalmatia southward to the Peloponnese of Greece, and also is found in western Turkey, and on the Krim (but see Fritz et al., 1998). This subspecies measures up to 17 cm (generally to 15 cm), but a population in the drainage system of the Dalmatian Neretva River may grow up to 19 cm. The carapce color varies from the orbicularis-type (over 90% of the populations) to the maculosa-type; the plastron is yellow with or without reduced dark mottling. The head is black with yellow reticulations (males) or spots (females); the throat is uniformly yellow. Old individuals are often macrocephalic. Males have yellow or white eyes. E. o. iberica Eichwald, 1831 (= E. o. kurae Fritz, 1994a; see Fritz, 1998), the Kura Valley pond turtle, is from the Kura Valley, the Transcaucasian Depression, and the eastern slope of the Greater Caucasus. Strikingly—and generally unlike other members of this group—the carapace (to 18 cm, but generally to 15 cm) of this subspecies changes from black with yellow pigmentation in juveniles and subadults to almost uniformly horn-colored in adults. The plastron is yellow, with or without dark seams, the head black with yellow spots or reticulations, and the throat yellow; the iris color of males is unknown. Except for the remarkable color change during ontogenesis, E. o. iberica is distinguished from E. o. hellenica by a mainly yellow foreleg. E. o. persica Eichwald, 1831 (= E. o. orientalis Fritz, 1994a; see Fritz, 1998), the eastern pond turtle, occurs along the southern coast of the Caspian Sea in northern Iran and adjacent Turkmenia. Its dark carapace (to 18 cm, but normally 10-15 cm) has numerous small light spots on each scute, these sometimes dominating the overall coloration. Plastron coloration is very variable, from all-yellow to all-black. The head usually is black with fine brown reticulations, changing into black with yellow spots on the neck; the throat generally is uniformly yellow. Iris of the male is red and possibly yellowish (Fritz, 1998). The eastern pond turtle can be separated from E. o. iberica by darker coloration and from both E. o. iberica and E. o. hellenica by a shorter intergular seam. A form morphologically nearly identical to E. o. hellenica occurs in southern Italy and on Sicily, and was referred to as E. o. cf hellenica by Fritz (1995a, b). Lenk et al. (1998) found that this form genetically is different from all other Emys subspecies.
The last group is monotypic, including only E. o. luteofusca Fritz, 1989a, the Central Turkey pond turtle. This subspecies was thought to be restricted to the Konya-Eregli region of central Turkey (Fritz, 1989a), but new data shows its range may be more extensive (Fritz et al., 1998). E. o. luteofusca is characterized by a rather large carapace (to 20.6 cm), and a small head. Carapacial coloration is tan to olive-brown, without extensive dark pigment; the plastron is uniformly yellow; head and throat are light-brown. Recently, however, darker individuals have been reported (Fritz et al., 1998), indicating that E. o. luteofusca may be far less distinctive than assumed by Fritz (1989a).
Fritz (1996, 1998) has proposed a zoogeographical scenario to account for the present distribution of the subspecies and their intergradation patterns. There are extensive zones of intergradation between the subspecies groups and individual subspecies: central and southern France, the Po Valley and southern Italy and Sicily, eastern Greece and the Balkan countries along the Danube watershed, central and eastern Turkey, and in the Precaucasus region (Fritz and Obst, 1995; Fritz, 1996, 1998). Although all currently recognized subspecies are listed above, the extent of division of the species seems questionable, as there is too much overlap in both descriptions and geographic ranges of several of the subspecies.
Habitat
Emys orbicularis lives in slow-moving water bodies with soft bottoms (mud or sand) and abundant aquatic vegetation, especially overhanging the banks. It has been taken from ponds, lakes, marshes, swamps, brooks, streams, rivers, and drainage canals.
The water in some of its habitats is quite brackish, and Dr. Konrad Klemmer has told us that around Frankfurt, West Germany, a few (probably released individuals) survive in highly polluted waters.
Natural History
Breeding occurs from March to May, depending on the latitude. Courtship observed by Ernst consisted of the male swimming behind and trailing the female, occasionally biting at her hindquarters and bumping her with his shell. He climbed upon her shell and held on with his forelegs while nudging her head and forelegs from above with his snout. Biting at this point was not observed, but has been reported by Street (1979). The male also scratched the female's posterior carapace and hindlimbs with his hindlimbs; possibly he was trying to secure a foothold. Coition eventually was successful, and the entire courtship and mating sequence occurred underwater. Loveridge and Williams (1957) reported that on warm spring nights during the mating season these terrapins emit short piping calls until they find a mate, after which the couple swim about together. No sounds were made by the turtles observed by Ernst.
Nesting occurs in May and June. Three to 16 eggs, usually 9 or 10, are laid at one time. The eggs are elliptical (39-30 x 22-18 mm) and have white, pliable, leathery shells. The incubation period varies with latitude, and at the northern extent of the range a long, hot summer is needed for successful hatching to occur; thus these E. orbicularis may only successfully reproduce once in four or five years. Hatching normally occurs from August to October, again depending on latitude.
Hatchlings have 20-25 mm carapaces, large heads, long tails, and a carapace with a well-developed medial keel and two lower lateral keels. At incubation temperatures of 24-28°C, only males are produced, but at an incubation temperature of 30°C, 96% of the hatchlings are females (Pieau, 1971, 1972, 1973).
Emys orbicularis is carnivorous, feeding on insects, crustaceans, mollusks, worms, salamanders, frogs, and fishes. Prey is actively stalked, and feeding may occur in or out of water.
The basking habit is well-developed, but this is a shy species which dives into the water at any disturbance. These turtles often hide buried in the soft bottom or up under overhanging vegetation along the bank. Having such an extensive range brings them under diverse climatic conditions. In the northern parts of their range they are forced to hibernate for long periods, but in the more southerly areas, they often aestivate to escape the summer's heat.
IUCN Red List Status (1996)
Lower risk: near threatened.