S. ERGENE, C. AYMAK, A. H. UÇAR Turk J Zool 2011; 35(3) 343-356 © TÜBİTAK Research Article doi:10.3906/zoo-0808-8 Carapacial scute variation in green turtle (Chelonia mydas) and loggerhead turtle (Caretta caretta) hatchlings in Alata, Mersin, Turkey Serap ERGENE1,*, Cemil AYMAK2, Aşkın Hasan UÇAR3 1Mersin University Sea Turtles Application and Research Center, Mersin - TURKEY 2Kasım Ekenler Highschool, Çamlıyayla, Mersin - TURKEY 3Osmaniye Korkut Ata University, Faculty of Science and Arts, Department of Biology, 80010, Osmaniye - TURKEY Received: 14.08.2008 Abstract: In recent years, Alata beach has been considered to be among 20 important sea turtle nesting areas in Turkey. In the 2003 nesting season, the carapacial scute variation of 1086 Chelonia mydas hatchlings (169 dead and 917 live) and 394 Caretta caretta hatchlings (74 dead and 320 live) from Alata beach in Mersin, Turkey, were examined within carapacial scute series and in carapacial scute pattern. Th e most frequent scute pattern observed for Ch. mydas hatchlings was 1 nuchal, 5 vertebrals, 1 pair of supracaudals, 4 pairs of costals, and 11 pairs of marginals. Th e pattern of 1 nuchal, 5 vertebrals, 1 pair of supracaudals, 5 pairs of costals, and 12 pairs of marginals was the most frequent pattern for loggerhead hatchlings. Using the Minitab 13.0 Z test for 2 proportions, the numbers of variations on the carapacial scutes of dead and live hatchlings of Ch. mydas and C. caretta were examined to see whether there was a relation between the rate of dead hatchlings and the number of variations on the carapacial scute. It was found that there was no relation between the changes in variation numbers and the mortality rates in Ch. mydas and C. caretta hatchlings. Key words: Carapace, scute variation, Chelonia mydas, Caretta caretta, Alata Alata, Mersin – Türkiye’deki yeşil deniz kaplumbağası (Chelonia mydas) ve iribaş kaplumbağa (Caretta caretta) yavrularının karapas kabuğundaki farklılaşmalar Özet: Son yıllarda, Alata kumsalı Türkiye’deki 20 önemli deniz kaplumbağası yuvalama alanlarından biri olarak değerlendirilmektedir. Mersin’deki Alata kumsalında, 2003 üreme sezonunda, 1086 Chelonia mydas, (169 ölü ve 917 canlı) ve 394 Caretta caretta, (74 ölü ve 320 canlı) yavrularının karapas kabuğundaki farklılaşma karapas plak serileri ve plak sıralanması bakımından incelenmiştir. Ch. mydas yavrularında en çok gözlemlenen kabuk serisi 1 nukal, 5 vertebral, 1 çift suprakaudal, 4 çift kostal ve 11 çift marginal şeklindedir. İribaş kaplumbağa için en çok tekrar eden kabuk serisi ise 1 nukal, 5 vertebral, 1 çift suprakaudal, 5 çift kostal ve 12 çift marginal şeklindedir. Minitab 13.0 ikili oran için Z testi kullanılarak, Ch. mydas ve C. caretta ölü ve canlı yavrularının karapas kabuklarındaki farklılaşma, ölü yavruların oranı ile karapas kabuğundaki plak farklılaşması arasında bir ilişki olup olmadığını görmek için incelenmiştir. Ch. mydas ve C. caretta yavrularında varyasyon sayısındaki değişiklikler ve ölüm oranları arasında herhangi bir ilişki bulunamamıştır. * E-mail: [email protected] 343 Carapacial scute variation in green turtle (Chelonia mydas) and loggerhead turtle (Caretta caretta) hatchlings in Alata, Mersin, Turkey Introduction According to this idea, in young turtles having Two sea turtle species, Caretta caretta and diff erent combinations than normal components, Chelonia mydas, nest regularly on the Turkish coast scutes undergo fusion during ontogeny so that the of the Mediterranean (Geldiay et al., 1982; Baran adult stage shows the normal reduced scute pattern. and Kasparek, 1989; Türkozan et al., 2003; Canbolat, On the other hand, Newman (1906) argues that supernumerary scutes are the atavistic reappearance 2004). Leatherback turtles (Dermochelys coriacea) of scutes lost during phylogeny (Türkozan et al., have also been reported on the Turkish coast (Oruç 2001). Özdemir and Türkozan (2006) explain the et al., 1997; Baran et al., 1998; Taşkavak et al., 1998; absence of adults with deviant numbers of costal, Sönmez et al., 2008). In Turkey, 20 important nesting vertebral, nuchal, or supracaudal scutes in 2 ways: beaches for sea turtles were determined in various the hatchlings with deviant scutes die before they studies (Baran and Kasparek, 1989; Baran, 1990; mature, or the scutes change to the normal number Baran et al., 1992; T.Ç.O.B., 2005; Aymak et al., 2005; with growth. According to Zangerl and Johnson Ergene et al., 2006a, Ergene et al., 2006b) (Figure 1). (1957), carapaces of turtles, while forming, remain Many scientists state that although the stable during chelonian evolution. arrangement and the number of scutes in turtles Parker (1901), Hildebrend (1930), and Zangerl are stable individual diff erences can be observed in (1969) claim that this abnormal situation occurs many turtle species (Gadow, 1899; Newman, 1906; accidentally or because of a disorder during Hewavisenthi and Kotagama, 1989; Mast and Carr, ontogenetic development. Hildebrend (1938) says 1989). Deraniyagala (1939) states that vertebral that the abnormal scutes of Diamondback terrapins scutes form carapace scutellation of a turtle. Vertebral are formed as a result of fl uctuations in oxygen scutes are a series of unpaired pieces in the median levels during incubation. In addition, Kazmaier and line, costal scutes are a bilateral series of paired scutes Robel (2001) report that the greater number of scute on each side of the vertebral scutes, and marginal anomalies in Terrapene ornata in central Kansas scutes are a bilateral series of paired scutes encircling may be the result of variations in temperature or the outer side of costal scutes. Th ere is a pair of moisture that cause stress during egg development supracaudal scutes between the last pair of marginal or incubation, or the mutagenic eff ects of excess scutes. A nuchal scute is located anteriorly between salinity during those periods. Deviations from the the fi rst pair of marginals (Figure 2). normal scute formulae of turtles may also result from In his study on C. caretta, Gadow (1899) concludes embryonic mutations, specifi c causes of which are that the proportion of variation in adults is less than unknown (Kazmaier and Robel, 2001). that of hatchlings. Starting from this fact, Gadow Yntema (1976) and Yntema and Mrosovsky (1899) puts forward the idea of orthogenetic variation. (1980) indicate that, regarding temperature- 38 Denizli TURKEY Adana Muğla Antalya Mersin Belek Kazanlı Kızılot Akyatan Ekincik Tekirova ALATA Dalyan Yumurtalık Fethiye Çıralı Demirtaş Samandağı Dalaman Göksu Patara Kumluca Gazipaşa 36 N Demre Anamur Deltas (Kale) Mediterranean Sea TURKEY Mediterranean Sea 50 0 50 100 150 km 27 30 33 36 Figure 1. Th e location of Alata in Turkey. 344 S. ERGENE, C. AYMAK, A. H. UÇAR NN M1 M1 C V 1 V1 1 C1 C2 V2 V2 C3 C2 V3 V3 C4 C3 V4 V4 C4 C5 V5 V5 M M12 11 SS SS Figure 2. Carapace in sea turtles A: Caretta caretta (Left ) B: Chelonia mydas (Right). (N: Nuchal, M: Marginal, S: Supracaudal, V: Vertebral, C: Costal) (Başoğlu and Baran, 1977). dependent sex determination, morphogenetic eff ects 30 km west of Mersin, and the nesting area is a 3-km- can be observed in turtles as a result of changes in long beach in front of the institute. temperature during incubation. As Mast and Carr Th roughout the study, the whole beach was (1989) state, among sea turtles, Lepidochelys has the monitored both night and day. During the night highest rate of deviation in scutes. Furthermore, studies, the sea turtles coming out of the sea to the handling the eggs during the development phase beach to nest were observed without interference. increases scute variation in Lepidochelys olivacea Eight live female Ch. mydas that were found laying (Hill, 1971) and causes the mortality rate of embryos eggs on the beach in 2003 and 5 Ch. mydas (sex to rise (Limpus et al., 1979). Th e above-mentioned unknown) that were found dead on the beach (3 in evidence demonstrates the eff ects of diff erent kinds 2002 and 2 in 2003) were measured and the scutes of environmental factors on scute variation during of 13 adult individuals in total were counted. Th e 5 incubation. stranded dead individuals were so badly decomposed Th e main aims of this study were to provide that it was not possible to determine their sex. When information about carapacial scute variation of the variation numbers on the carapacial scutes of C. caretta and Ch. mydas hatchlings and to detect the adult Ch. mydas were evaluated, the sex of the whether there is a relationship between variation in adults and their being dead or alive were not taken scute numbers and the mortality rate of hatchlings into consideration. Only an assessment of the general of 2 species. situation of the 13 adults in total was made. Emergences from the natural nests were recorded during the hatchling season. Furthermore, 5-10 days Materials and methods aft er the fi rst emergence of hatchlings, openings were Alata beach is located inside the borders of Alata made in the nests to gather nest and egg data, count Horticultural Research Institute, which is one of the dead embryos, and check the number of hatchlings. 1st degree natural sites. It is 3 km east of Erdemli and In this study, all of the hatchlings found were grouped 345 Carapacial scute variation in green turtle (Chelonia mydas) and loggerhead turtle (Caretta caretta) hatchlings in Alata, Mersin, Turkey as dead or alive and their scutes were counted. Both individuals with 0, 1, 2, or 3 variations and C. caretta live and dead hatchlings were found in the nests at individuals with 0, 1, or 2 variations were compared nest excavation. Also, they were encountered both in pairs. in the nests and between the nests and the sea when they naturally emerged to orient toward the sea. Most of the live hatchlings found at nest excavation were Results in apparent good health with vigorous movements.