Morphologic and Serologic Comparison of Two Turkish Populations of Mauremys rivulata and Mauremys caspica
ABSTRACT
Two Turkish populations of Mauremys caspica and Mauremys rivulata were compared morphologically, serologically, and ecologically. Morphometric differences were noted among sexes and populations. Electrophoretic patterns demonstrated significant differences between the taxa and supported their status as distinct species.
Five species of freshwater turtles are known from Turkey: Mauremys caspica, Mauremys rivulata, Emys orbicularis, Rafetus euphraticus, and Trionyx triunguis. Mauremys caspica (Fig. 1) was first described from Pirsagat (west of Baku) in the Transcaucasus by Gmelin as Testudo caspica in 1774. Mauremys caspica is known from eastern and southeastern Anatolia and from the middle Anatolian Plateau, whereas the range of Mauremys rivulata extends from southeastern Europe to the Middle East, including the area the former Yugoslavia, Greece, Aegean Islands to Crete and Cyprus, and from Bulgaria through western Anatolia and the coastal strip of Syria into Lebanon, Israel, and Jordan (Haas 1952; Mertens and Wermuth 1960; Wermuth and Mertens 1961; Başoğlu and Baran 1977; Iverson 1986; Ernst and Barbour 1989; Fritz and Freytag 1993; Baran and Atatür 1998; Taşkavak et al. 1998; Wischuf and Fritz 2001; Wischuf and Busack 2001).
Citation: Chelonian Conservation and Biology 5, 1; 10.2744/1071-8443(2006)5[10:MASCOT]2.0.CO;2
The number of studies regarding Mauremys is very limited for Turkey. Boulenger (1926) reported the sympatric occurrence of M. caspica and M. rivulata in the vicinity of Ankara. Bird (1936) stated that the adults of 2 forms could easily be distinguished. Referring to the sympatric occurrence near Ankara recorded by Boulenger (1926), Bird (1936) elevated both forms to full species rank. Bodenheimer (1944) accepted that both taxa are full species and claimed to have seen M. rivulata and M. caspica in the same locality in central Turkey, namely Eymir Lake near Ankara. With the exception of the specimens mentioned by Boulenger (1926), Bodenheimer (1944) is the sole other author who reported that he has seen specimens of both taxa from the same locality. Later, most authors treated caspica and rivulata as subspecies of M. caspica (e.g., Mertens 1946; Loveridge and Williams 1957; Wermuth and Mertens 1961, 1977).
Eiselt and Spitzenberger (1967) discussed the general range of caspica and rivulata in their comprehensive study and published the first detailed locality map for both taxa in Turkey. This map was reproduced with a few new records by Başoğlu and Baran (1977) and served as the basis for papers by Busack and Ernst (1980), Fritz and Freytag (1993), Fritz and Wischuf (1995, 1997).
Eiselt and Spitzenberger (1967) raised again the question whether caspica and rivulata would be better treated as full species. However, they did not draw any definite conclusion. Fritz and Freytag (1993) recorded the occurrence of caspica in central Anatolia for the first time. Schweiger (1994) added 15 new localities for caspica, 1 in central, 5 in northern, and the rest in eastern Anatolia. Taşkavak and Reimann (1998) also confirmed the existence of this form in central Anatolia. Taşkavak et al. (1998) gave 3 additional new localities for caspica from central Anatolia. Fritz and Wischuf (1995) scanned all the existing sources on M. caspica and stated that M. caspica rivulata is confined to a warm Mediterranean climate and M. caspica caspica to a continental steppe climate. Further, they concluded that there is no proof for the occurrence of rivulata in the continental high plateau of Central Anatolia. They presented evidence that the earlier reported rivulata specimens from the environs of Ankara (Boulenger 1926; Bird 1936) were the result of a locality confusion of museum specimens. Fritz and Wischuf (1997) demonstrated that caspica and rivulata inhabit parapatric ranges. In the contact zone of both, no intergradation was recorded and only at 2 localities have a few hybrids been recorded. Therefore, Fritz and Wischuf (1997) raised caspica and rivulata to full specific rank again.
Baran and Atatür (1998) communicated the general status and distribution of the genus Mauremys in Turkey. Eiselt and Spitzenberger (1967) and Fritz and Freytag (1993) gave the Euphrates and the Ceyhan rivers as the definite border between the ranges of rivulata and caspica. Busack and Ernst (1980) misinterpreted the map in Başoğlu and Baran (1977) and concluded that rivulata and caspica were conspecific. The works of Çevik (1982) on Turkish Thracian turtles and Tok (1993) on the turtles of Reşadiye Peninsula gave only a rough idea for these regions. Taşkavak et al. (1997) revealed statistically important morphological differences between 2 marginal populations of M. caspica rivulata in Anatolia and Ayaz (1998) described the ecology and taxonomic status of Mauremys in the Aegean region.
We here compare 2 separate Turkish populations of caspica and rivulata morphologically and serologically to test the differences between the 2 taxa. Furthermore, some ecological properties of both populations are also compared.
METHODS
A total of 26 (8 male; 18 female) specimens of M. caspica from Nusaybin-Mardin in eastern Turkey, and 33 (14 male; 19 female) specimens of M. rivulata, from Menemen-İzmir in western Turkey, were examined. The specimens were released after measurements had been taken. For morphological measurements, Fritz's (1995) terminology on Emys orbicularis is used. The morphological measurements used in this study to compare the specimens are as follows. Straight carapace length (SCL) is the straight-line measurement from the outermost projection of the nuchal scute to the posterior end of the supracaudals. Curved carapace length (CCL) is the curved-line measurement from the anterior to the posterior edge of the carapace. Carapace width (CW) is the straight-line measurement between the lateral margins of the carapace at the midline. Carapace height (CH) is the vertical measurement between the highest point of the carapace and the shallowest point of the plastron. Plastron length (PL) is the straight-line measurement from the outermost projection of the gular end of the plastron to the posterior tip of the anal end of the plastron. Plastron width-1 (PW-1) is the straight-line measurement between the lateral margins of the plastron at the humeral scutes. Plastron width-2 (PW-2) is the straight-line measurement between the lateral margins of the plastron at the abdominal scutes. Gular suture length (GuL) is the length of gular scute at midseam. Humeral suture length (HuL) is the length of humeral scute at midseam. Pectoral suture length (PecL) is the length of pectoral scute at midseam. Abdominal suture length (AbdL) is the length of abdominal scute at midseam. Femoral suture length (FemL) is the length of femoral scute at midseam. Anal suture length (AnL) is the length of anal scute at midseam. Nuchal length (NL) is the length from the anterior edge of the neck to its posterior end. Nuchal width (NW) is the width of the neck at the posterior end. Morphometric ratios (SCL/CCL, SCL/CW, SCL/CH, SCL/PL, SCL/GuL, SCL/HuL, SCL/PecL, SCL/AbdL, SCL/FemL, SCL/AnL, SCL/PW-1, SCL/PW-2, SCL/NL, SCL/NW, PL/PW-1, PL/PW-2, NL/NW, CW/SCL, CW/CCL, CW/CH, CW/PL, CW/GuL, CW/HuL, CW/PecL, CW/AbdL, CW/FemL, CW/AnL, CW/PW-1, CW/PW-2, CW/NL, CW/NW) were developed with the combinations of various characters to indicate similarities and differences between the populations and also between the sexes. First, an independent t-test was performed utilizing the above-mentioned 31 ratios to compare males and females within the same populations. Later, females and males were separately investigated between the 2 populations by analysis of variance (ANOVA). Statistical analyses were carried out using STATISTICA version 6.0. On capture, each specimen's color and pattern characteristics were also recorded.
For serological investigation, a total of 12 specimens (6 male; 6 female) from the same localities, with an equal number of each sex from each locality, were analyzed for blood-serum proteins. Blood was obtained from animals according to the method of Avery and Vitt (1984). Blood-serum proteins were separated using the polyacrylamide disc-electrophoresis method of Davis (1964), slightly modified by Özeti and Atatür (1979) and Arıkan (1983). The analysis of blood-serum proteins of both populations was conducted at the same conditions (pH 8.3). The qualitative evaluation of the separations were done on densitometric tracing curves, obtained from a Gelman ACD-15 model 39430 densitometer scanning at 500 nm. The electropherograms were also visually compared. In order to facilitate the comparison of the electropherograms, each graph was separated by dashed lines (A, B, C, D, and E), which corresponded to the same area on both graphs.
RESULTS AND DISCUSSION
Distribution
Eiselt and Spitzenberger (1967) and Fritz and Freytag (1993) reported the Euphrates and Ceyhan rivers as the definite border between the ranges of rivulata and caspica. Earlier reports of a sympatric occurrence near Ankara (Boulenger 1926, based on the same specimens repeated in Bird 1936; Bodenheimer 1944) proved to be wrong or doubtful (Fritz and Wischuf 1995). Taşkavak (1992) stated that in Gölbaşı, Adıyaman, in the Ceyhan River and in a tributary of the Euphrates, the Göksu River, the distributions of caspica and rivulata approach each other as close as 5 km. Here he recorded the specimens caught from the Ceyhan River as rivulata and those captured from the Göksu River as caspica. According to him, the easternmost border of the range of rivulata in Anatolia coincides with Afrin and Karasu creeks, which empty to Asi River. Here we provide an updated distribution map of both species in Turkey (Fig. 2).
![Figure 2. Updated distribution map of Mauremys rivulata and Mauremys caspica (modified from Fritz and Freytag 1993). ++++ = border line of internally drained central basin of Anatolia]; ▪ = literature records for M. caspica, • = literature records for M. rivulata; ▴ = Menemen (İzmir), ▾ = Nusaybin (Mardin); * = the sole M. caspica × M. rivulata hybrid known from Turkey, from 26 km south of Vilayet Gaziantep (Fritz and Wischuf 1997). Only localities not plotted on the map in Fritz and Freytag (1993) bear numbers. ZDEU = Ege University, Department of Zoology. / 1) Centrum-Datça/Muğla, ZDEU 50/1990, July 1990 (Tok 1999); 2) Çubucak-Marmaris/Muğla, ZDEU 73/1991, April 1991 (Tok 1999); 3) Eşen Çayı-Fethiye/Muğla, ZDEU 112/1997, July 1997 (Ayaz 1998); 4) Ekinanbarı Village-Milas/Muğla, ZDEU 122/1997, August 1997 (Ayaz 1998); 5) Şaphane/Kütahya, ZDEU 114/1997, July 1997 (Ayaz 1998); 6) Üyücek River-Burhaniye/Balıkesir, ZDEU 120/1997, August 1997 (Ayaz 1998); 7) 15 km W of Ecebat, ZDEU 323/1977, August 1977 (Çevik 1982); 8) Emirali Village-Malkara, ZDEU 143/1981, May 1981 (Çevik 1982); 9) Ereğli, ZDEU 132/1978, May 1978 (Tekirdağ) (Çevik 1982); 10) Hayrabolu, ZDEU 133/1981, May 1981 (Çevik 1982); 11) Babaeski, ZDEU 132/1981, May 1981 (Çevik 1982); 12) Hasköy, 15 km ESE of Muş, May 1991 (Schweiger 1994); 13) Hilvan, 16 km N of Şanlıurfa, August 1988 (Schweiger 1994); 14) Hilvan, 12 km N of Şanlıurfa, August 1988 (Schweiger 1994); 15) Çaylarbaşı, 15 km N of Hilvan, August 1988 (Schweiger 1994); 16) Pasinler, 30 km E of Erzurum, May 1993 (Schweiger 1994); 17) 15 km ENE of Horosan, May 1991 (Schweiger 1994); 18) 7 km W of Karakurt, May 1993 (Schweiger 1994); 19) Aydın Kavak, 7 km NE of Kağızman, May 1989 (Schweiger 1994); 20) 5 km S of Kağızman, May 1989 (Schweiger 1994); 21) Amasya, May 1989 (Schweiger 1994); 22) Turhal, 14 km ESE of Amasya, August 1988 (Schweiger 1994); 23) Havza, 60 km SW of Samsun, May 1993 (Schweiger 1994); 24) Merzifon, 80 km SW of Samsun, May 1993 (Schweiger 1994); 25) 25 km E of Tosya, May 1988 (Schweiger 1994); 26) Bünyan, 35 km ENE of Kayseri, May 1989 (Schweiger 1994).](/view/journals/ccab/5/1/i1071-8443-5-1-10-f02.gif)
![Figure 2. Updated distribution map of Mauremys rivulata and Mauremys caspica (modified from Fritz and Freytag 1993). ++++ = border line of internally drained central basin of Anatolia]; ▪ = literature records for M. caspica, • = literature records for M. rivulata; ▴ = Menemen (İzmir), ▾ = Nusaybin (Mardin); * = the sole M. caspica × M. rivulata hybrid known from Turkey, from 26 km south of Vilayet Gaziantep (Fritz and Wischuf 1997). Only localities not plotted on the map in Fritz and Freytag (1993) bear numbers. ZDEU = Ege University, Department of Zoology. / 1) Centrum-Datça/Muğla, ZDEU 50/1990, July 1990 (Tok 1999); 2) Çubucak-Marmaris/Muğla, ZDEU 73/1991, April 1991 (Tok 1999); 3) Eşen Çayı-Fethiye/Muğla, ZDEU 112/1997, July 1997 (Ayaz 1998); 4) Ekinanbarı Village-Milas/Muğla, ZDEU 122/1997, August 1997 (Ayaz 1998); 5) Şaphane/Kütahya, ZDEU 114/1997, July 1997 (Ayaz 1998); 6) Üyücek River-Burhaniye/Balıkesir, ZDEU 120/1997, August 1997 (Ayaz 1998); 7) 15 km W of Ecebat, ZDEU 323/1977, August 1977 (Çevik 1982); 8) Emirali Village-Malkara, ZDEU 143/1981, May 1981 (Çevik 1982); 9) Ereğli, ZDEU 132/1978, May 1978 (Tekirdağ) (Çevik 1982); 10) Hayrabolu, ZDEU 133/1981, May 1981 (Çevik 1982); 11) Babaeski, ZDEU 132/1981, May 1981 (Çevik 1982); 12) Hasköy, 15 km ESE of Muş, May 1991 (Schweiger 1994); 13) Hilvan, 16 km N of Şanlıurfa, August 1988 (Schweiger 1994); 14) Hilvan, 12 km N of Şanlıurfa, August 1988 (Schweiger 1994); 15) Çaylarbaşı, 15 km N of Hilvan, August 1988 (Schweiger 1994); 16) Pasinler, 30 km E of Erzurum, May 1993 (Schweiger 1994); 17) 15 km ENE of Horosan, May 1991 (Schweiger 1994); 18) 7 km W of Karakurt, May 1993 (Schweiger 1994); 19) Aydın Kavak, 7 km NE of Kağızman, May 1989 (Schweiger 1994); 20) 5 km S of Kağızman, May 1989 (Schweiger 1994); 21) Amasya, May 1989 (Schweiger 1994); 22) Turhal, 14 km ESE of Amasya, August 1988 (Schweiger 1994); 23) Havza, 60 km SW of Samsun, May 1993 (Schweiger 1994); 24) Merzifon, 80 km SW of Samsun, May 1993 (Schweiger 1994); 25) 25 km E of Tosya, May 1988 (Schweiger 1994); 26) Bünyan, 35 km ENE of Kayseri, May 1989 (Schweiger 1994).](/view/journals/ccab/5/1/full-i1071-8443-5-1-10-f02.gif)
![Figure 2. Updated distribution map of Mauremys rivulata and Mauremys caspica (modified from Fritz and Freytag 1993). ++++ = border line of internally drained central basin of Anatolia]; ▪ = literature records for M. caspica, • = literature records for M. rivulata; ▴ = Menemen (İzmir), ▾ = Nusaybin (Mardin); * = the sole M. caspica × M. rivulata hybrid known from Turkey, from 26 km south of Vilayet Gaziantep (Fritz and Wischuf 1997). Only localities not plotted on the map in Fritz and Freytag (1993) bear numbers. ZDEU = Ege University, Department of Zoology. / 1) Centrum-Datça/Muğla, ZDEU 50/1990, July 1990 (Tok 1999); 2) Çubucak-Marmaris/Muğla, ZDEU 73/1991, April 1991 (Tok 1999); 3) Eşen Çayı-Fethiye/Muğla, ZDEU 112/1997, July 1997 (Ayaz 1998); 4) Ekinanbarı Village-Milas/Muğla, ZDEU 122/1997, August 1997 (Ayaz 1998); 5) Şaphane/Kütahya, ZDEU 114/1997, July 1997 (Ayaz 1998); 6) Üyücek River-Burhaniye/Balıkesir, ZDEU 120/1997, August 1997 (Ayaz 1998); 7) 15 km W of Ecebat, ZDEU 323/1977, August 1977 (Çevik 1982); 8) Emirali Village-Malkara, ZDEU 143/1981, May 1981 (Çevik 1982); 9) Ereğli, ZDEU 132/1978, May 1978 (Tekirdağ) (Çevik 1982); 10) Hayrabolu, ZDEU 133/1981, May 1981 (Çevik 1982); 11) Babaeski, ZDEU 132/1981, May 1981 (Çevik 1982); 12) Hasköy, 15 km ESE of Muş, May 1991 (Schweiger 1994); 13) Hilvan, 16 km N of Şanlıurfa, August 1988 (Schweiger 1994); 14) Hilvan, 12 km N of Şanlıurfa, August 1988 (Schweiger 1994); 15) Çaylarbaşı, 15 km N of Hilvan, August 1988 (Schweiger 1994); 16) Pasinler, 30 km E of Erzurum, May 1993 (Schweiger 1994); 17) 15 km ENE of Horosan, May 1991 (Schweiger 1994); 18) 7 km W of Karakurt, May 1993 (Schweiger 1994); 19) Aydın Kavak, 7 km NE of Kağızman, May 1989 (Schweiger 1994); 20) 5 km S of Kağızman, May 1989 (Schweiger 1994); 21) Amasya, May 1989 (Schweiger 1994); 22) Turhal, 14 km ESE of Amasya, August 1988 (Schweiger 1994); 23) Havza, 60 km SW of Samsun, May 1993 (Schweiger 1994); 24) Merzifon, 80 km SW of Samsun, May 1993 (Schweiger 1994); 25) 25 km E of Tosya, May 1988 (Schweiger 1994); 26) Bünyan, 35 km ENE of Kayseri, May 1989 (Schweiger 1994).](/view/journals/ccab/5/1/inline-i1071-8443-5-1-10-f02.gif)
Citation: Chelonian Conservation and Biology 5, 1; 10.2744/1071-8443(2006)5[10:MASCOT]2.0.CO;2
Morphometrics
Mauremys rivulata females are larger than males, whereas in M. caspica, males are larger (Table 1). The largest animals measured were males at 215-mm SCL from both populations. Fritz and Wischuf (1997) measured the largest caspica of both sexes as 250-mm SCL. Based on 844 specimens, they reported a bimodal distribution in the size of rivulata and caspica with dwarf and giant males. We found an average SCL of 169.9 and 177.2 mm for caspica and rivulata, respectively, and a unimodal size distribution. Taşkavak et al. (1997) recorded the maximum SCL at 217 mm for the 2 marginal rivulata populations. Tok (1999) recorded the maximum SCL as 172 mm for rivulata from Datça Peninsula, western Turkey.
The independent t-test yields a statistically significant difference between the males and females of both populations (Table 2). Siebenrock (1913) noted sexual dimorphism in M. caspica and stated that there may be important differences among the morphological measurements. He recorded the most variable character between the sexes as carapace height.
When the data for both sexes are analyzed separately, it is possible to differentiate the caspica and rivulata populations in terms of some morphometric characters (Table 3). Fritz and Wischuf (1997) were unable to detect consistent morphometric differences between both species by simple univariate statistics because of a high overlap in all characters. Regarding plastral formula, they found a high degree of variability. This result was supported by our findings as well. Except for 2 individuals, the abdominal suture was the longest in the rivulata population. The sequence of the other sutures showed major variation; 11 combinations were recorded in the population. In the caspica population, a total of 11 combinations were noted as well. In contrast to rivulata, the femoral suture was the longest suture in the caspica population. Tok (1999) stated that apart from 2 specimens, the abdominal suture was the longest suture in his specimens. He also noted that the anal suture was always shorter than the femoral and pectoral sutures. This was also confirmed in our study. Ernst and Barbour (1989) give the plastral formulae for males and females of rivulata in order of decreasing length at the midline: AbdL > FemL > PecL > GuL > AnL > HuL. This formula corresponds to our general formulae for the whole population. The same authors communicated the plastral formula for caspica males and females in order of decreasing length at the midline as FemL > AbdL > PecL > GuL > HuL > AnL and AbdL > FemL > PecL > GuL > HuL > AnL, respectively. We recorded only 1 formula for males and females, and this formula is identical with the formula for males given by Ernst and Barbour (1989).
Serology
In quantitative examination of 6 specimens of M. caspica from Nusaybin (Mardin), a total of 10 fraction groups, 1 albumin and generally (83%) 9 globulin fractions were observed. All 6 specimens of M. rivulata from Menemen (İzmir) comprised 11 fraction groups (Fig. 3).
Citation: Chelonian Conservation and Biology 5, 1; 10.2744/1071-8443(2006)5[10:MASCOT]2.0.CO;2
In qualitative comparisons between M. caspica and M. rivulata, the distribution of globulin fractions showed differences. The globulin in M. rivulata contained 2 joined fractions at the C1–2 region (Fig. 3B). Furthermore, the fractions at the C region were generally in lower density. Mauremys caspica comprised a different high-density fraction in addition to globulin fractions at the C region (Fig. 3A). Both total fractions of serum proteins and distribution of globulin fractions showed important differences between the 2 populations. Merkle (1975), having studied 17 different protein systems, found no difference between caspica and rivulata. However, he worked on plasma and enzymes with starch gel electrophoresis and found no difference in terms of albumins. We used polyacrylamide disc-electrophoresis and worked on blood-serum proteins and found differences in globulins. The qualitative comparison of electrophoretic pattern (electropherograms) of blood-serum proteins verified a significant difference between caspica and rivulata and supports the specific status of both taxa. In addition, recent investigations on the molecular phylogeny of Mauremys support the specific status of both taxa (Barth et al. 2004).
Color and Pattern
Fritz and Wischuf (1997) showed in their study that considerable diagnostic differences exist between caspica and rivulata: 1) the carapace in caspica has a double ocellus (like an “8”) on each costal scute, and in rivulata, a net-like pattern; 2) in younger individuals, the plastron bears isolated dark spots on a yellow background in caspica, in rivulata the plastron has a massive dark figure; 3) in caspica the bridge is yellow with dark scute seams, in rivulata the bridge is massive dark to black; 4) the submarginals in caspica, if not entirely yellow, consistently bear 2 small dots, in rivulata there is a large ocellus on the seam between 2 submarginals, so that 2 half-ocelli are positioned on each submarginal scute; 5) in caspica the dorsal head is unpatterned, in rivulata it bears a contrasting vermiform pattern; 6) the snout is distinctly striped in caspica, in rivulata feebly striped or unstriped; 7) in caspica yellow stripes run from the eye through the temporal region to the neck, in rivulata the neck stripes often do not reach the eye and in the temporal regions the stripes are often wrinkled; 8) the stripes on the forelegs are wide in caspica and narrow in rivulata; and 9) in caspica the thighs bear several vertical yellow stripes which are either absent or only 1 is present in rivulata. Our color and pattern characteristics totally correspond to those given by Fritz and Wischuf (1997).
Ecological Observations
The ecological properties of the habitats also showed great variation, especially in terms of water salinity (S = 0.2 ppt for caspica, 1 ppt for rivulata) and conductivity (μS = 470 μS25° for caspica, 1920 μS25° for rivulata). The pH was measured as 7.62 in the water of caspica; it was 7.68 for the water of rivulata.
The natural vegetation consists of the following species for caspica: Populus nigra, Poa perennis, Salix alba, Alnus orientalis, Ficus carica, Phragmites communis, Ulmus minor, Mentha spicata, and Rubus caesius. The vegetation in the habitat of rivulata consists of Vites agnus-castus, Tamarix smyrnensis, Platanus orientalis, Ficus carica, Phragmites australis, Salix sp., and Populus sp. Fritz and Wischuf (1997) have hypothesized that rivulata is confined to a warm Mediterranean climate and caspica to a continental steppe. Our observations do not contradict this hypothesis.
Conservation and Threats
Freshwater turtles face a number of threats in Turkey. In addition to dangers such as drainage of wetlands and the facing of drainage ditches with concrete slabs, agricultural practices such as excessive groundwater extraction and overuse of pesticides and fertilizers are serious concerns. Furthermore, in recent years, pet trade is an important threat because imported pet turtles are more expensive than are native turtles. For a pet trade dealer it is much cheaper, easier, and more profitable to obtain native specimens. Taşkavak et al. (1997) stated that rivulata specimens collected from Bursa have sold in pet shops in Ankara and therefore any recent existence of rivulata specimens in Ankara region may result from the release of those pet terrapins to natural habitats. In this context, the risk of loss of biodiversity because of hybridization has to be mentioned. Whereas under natural conditions hybrids between both species are rare, perhaps due to different habitat requirements, released specimens can cause genetic contamination as many chelonians, even very distantly related ones, are known to hybridize (Galgon and Fritz 2002).
Additionally, construction of dams has degraded the natural habitats of some freshwater turtles, especially in eastern Turkey. In order to prevent unwanted negative effects on the freshwater turtles, regulations should be instituted and enforced. Among others, these regulations could include the strict control of illegal pet trade or encouraging captive breeding farms for commercial purposes for the pet trade.
Mauremys caspica from Nusaybin (Mardin), Turkey.
Updated distribution map of Mauremys rivulata and Mauremys caspica (modified from Fritz and Freytag 1993). ++++ = border line of internally drained central basin of Anatolia]; ▪ = literature records for M. caspica, • = literature records for M. rivulata; ▴ = Menemen (İzmir), ▾ = Nusaybin (Mardin); * = the sole M. caspica × M. rivulata hybrid known from Turkey, from 26 km south of Vilayet Gaziantep (Fritz and Wischuf 1997). Only localities not plotted on the map in Fritz and Freytag (1993) bear numbers. ZDEU = Ege University, Department of Zoology.
1) Centrum-Datça/Muğla, ZDEU 50/1990, July 1990 (Tok 1999); 2) Çubucak-Marmaris/Muğla, ZDEU 73/1991, April 1991 (Tok 1999); 3) Eşen Çayı-Fethiye/Muğla, ZDEU 112/1997, July 1997 (Ayaz 1998); 4) Ekinanbarı Village-Milas/Muğla, ZDEU 122/1997, August 1997 (Ayaz 1998); 5) Şaphane/Kütahya, ZDEU 114/1997, July 1997 (Ayaz 1998); 6) Üyücek River-Burhaniye/Balıkesir, ZDEU 120/1997, August 1997 (Ayaz 1998); 7) 15 km W of Ecebat, ZDEU 323/1977, August 1977 (Çevik 1982); 8) Emirali Village-Malkara, ZDEU 143/1981, May 1981 (Çevik 1982); 9) Ereğli, ZDEU 132/1978, May 1978 (Tekirdağ) (Çevik 1982); 10) Hayrabolu, ZDEU 133/1981, May 1981 (Çevik 1982); 11) Babaeski, ZDEU 132/1981, May 1981 (Çevik 1982); 12) Hasköy, 15 km ESE of Muş, May 1991 (Schweiger 1994); 13) Hilvan, 16 km N of Şanlıurfa, August 1988 (Schweiger 1994); 14) Hilvan, 12 km N of Şanlıurfa, August 1988 (Schweiger 1994); 15) Çaylarbaşı, 15 km N of Hilvan, August 1988 (Schweiger 1994); 16) Pasinler, 30 km E of Erzurum, May 1993 (Schweiger 1994); 17) 15 km ENE of Horosan, May 1991 (Schweiger 1994); 18) 7 km W of Karakurt, May 1993 (Schweiger 1994); 19) Aydın Kavak, 7 km NE of Kağızman, May 1989 (Schweiger 1994); 20) 5 km S of Kağızman, May 1989 (Schweiger 1994); 21) Amasya, May 1989 (Schweiger 1994); 22) Turhal, 14 km ESE of Amasya, August 1988 (Schweiger 1994); 23) Havza, 60 km SW of Samsun, May 1993 (Schweiger 1994); 24) Merzifon, 80 km SW of Samsun, May 1993 (Schweiger 1994); 25) 25 km E of Tosya, May 1988 (Schweiger 1994); 26) Bünyan, 35 km ENE of Kayseri, May 1989 (Schweiger 1994).
Electropherograms (gel photographs) showing the electrophoretic separation of the blood serum proteins of adult specimens of Mauremys caspica (A, top) and Mauremys rivulata (B, bottom). OD = optic density; S = starting point.
