Studies On The Morphological Differences Between Hainan Four Eye-spotted Turtles (Sacalia Hainanensis) And Four Eye-spotted Turtles (Sacalia Quadriocellata)

The Four Eye-spotted turtle(Sacalia quadriocellata)is a Southeast Asian species distributed in the Chinese provinces of Guangdong,Guangxi,Jiangxi and Hainan,and Laos and Vietnam.Athough it has been considered as a single species,comparisons between Four Eye-spotted turtles and Eye-spotted turtles base on morphology and internal anatomy confirm that the Four Eye-spotted turtle is a valid species.Some academics consider the Four Eye-spotted turtle found in Dali Diaoluo Hainan to be a new species,Clemmys bealii quadriocellata(Li Zhixun,1958)base on body shape different from turtles elsewhere.The application of the molecular biology method of mitochondrial 16 s DNA sequence analysis has shown that Four Eye-spotted turtle can be divided into two species: Sacalia quadriocellata from Vietnam and Laos and Sacalia insulenis(Adler,1962)comb.Nov.from Hainan and the mainland.Using 4 Four Eye-spotted turtles from Guangdong Province to do 16 sDNA mitochondrial sequence comparison with genetic material from the Guangxi region reveals a match between these 4 and the Guangxi DNA,whereas these turtles' sequence and that of Hainan Four Eye-spotted turtles are far apart.Therefore,it is recommended that the term Hainan Four Eye-spotted turtle(Sacalia hainanensis)be used for it,while the mainland population be named the Four Eye-spotted turtle(Sacalia quadriocellata).In order to study the taxonomic status of the Hainan Four Eye-spotted turtle(Sacalia insulensis),restricted to Hainan island,86 adult Four Eye-spotted turtles from three regions(Hainan,Guangxi and Guangdong)were analyzed in terms of morphological variation.This study was based on physical specimen morphology measurements and has been described in the literature related to the measurement data carried out on the basis of morphological differences between the populations analyzed.The main results are presented as follows: Head morphology of Hainan Four Eye-spotted turtle and Four Eye-spotted turtle:Form the observation of physical specimens of known origin,and in accordance with literature sources,Four Eye-spotted turtle heads and Hainan Four Eye-spotted turtle heads were significantly different morphologically.Male Four Eye-spotted turtles from mainland southeast Asian coastal areas have two large red patches on the chin,and the inside edge of the proximal post-ocular spots are in contact with one another,in a "V" shape.In contrast,the female Hainan Four Eye-spotted turtles chin has only a few small red patches,the inside edge of the proximal post-ocular spots are not in contact with one another,not in a "V" shape.Comparison of adult female head features reveal: The Four Eye-spotted turtle chin has two large yellow or white patches,only slightly connected anteriorly,Hainan Four Eye-spotted turtle's chin lacks patches or has very small yellowish-white patches.These results indicate that Hainan Four eye-spotted turtles and Four eye-spotted turtles have significant differences in the pigmentation of the head.Morphological measurements of the head markings and comparison of the patches show that Hainan Four Eye-spotted turtles and Four Eye-spotted turtles have significantly different markings on the chin,and patch details(p=0.000<0.05,Mann-Whitney U test).According to the head morphology ANCOVA using head length as a covariate the results also show Four eye-spotted turtle head length(t = 7.687,df = 50,p = 0.001),head width(F(1 50)= 12.071,p = 0.00)and head height(F(1 50)= 6.079,p = 0.017)were significantly greater than the Four eye-spotted turtle.Using five head shape measured values as the principal component factor analysis show that:The scatter plot distribution of Four Eye-spotted turtles and Hainan Four Eye-spotted turtles in the principal component analysis has its own center of centroid,indicating the existence of species-specific head morphological differences.Results between plastron angle principal component analysis and Canonical discriminant analysis were consistent.The head morphological features can be better utilized to separate both species.The carapace morphology differences between Hainan Four Eye-spotted turtles and Four Eye-spotted turtles:Forty-one morphological measurements were used for statistical analysis.We used one-way ANOVA to identify the difference of 33 measured values without sexual dimorphism.Discriminant function analysis of Hainan Four Eye-spotted turtle identification accuracy was 88.5%,for Four eye-spotted turtle,the correct identification rate was 100%,the overall rate of correct identification was 90.4%.The results show that using the head morphological features may better distinguish between both species.The results show that the CH / CL,PL2 / CL,PPW1 / CL measurement in the Hainan Four Eye-spotted turtle is greater than in the Four Eye-spotted turtle,while the PW / CL ratio comparing the measured values is greater in the mainland than in Hainan Four Eye-spotted turtles.The differences were significant.Results showed that the carapace morphology between Hainan Four Eye-spotted turtles and Four Eye-spotted turtles is due to in environmental and genetic differences.The life history strategies of both species evidently account for the morphological differences in the carapaces of each species.Hainan Four Eye-spotted turtles have a larger anterior space(ACW)and intraperitoneal volume(CH / CL)and a relatively large posterior space(PPW1 / CL)which increases the spawning capacity associated with lower survival pressure.Four Eye-spotted turtles tend to have a more extensive shell protection area(PW/CL,ABSW/CL,ABSL/CL)and a more streamlined shell(low CH/CL ratio),possibly in response to greater survival pressure and environmental demands.Data analysis with sexually dimorphic morphometric characteristics shows that both Four Eye-potted turtles and Hainan Four Eye-spotted turtles females were significantly larger than the males.Morphological measurements comparing sexually dimorphic traits found that the Four Eye-spotted turtle has a greater protection area(PL1 / CL)and greater lateral coverage area(CW1 / CL),reflecting greater survival pressure on the Four Eye-spotted turtle.Female Hainan Four Eye-spotted turtle has a broader second rib width(2COSW / CL)and longer bridge length(BL / CL)than the female Four Eye-spotted turtle,which do not need to over-protect themselves.The Hainan population thus enhances the ability to reproduce.Similarly,male sexually dimorphic morphology measurements favor the Hainan Four Eye-spotted turtle because its carapace attains a greater length(CL,NL / CL)as well as having a wider plastron(W1 / CCL)enabling better body protection.At the same time,the Four Eye-spotted turtle has a shortened bridge(BL / CL)to increase the space for limbs,thus improving their mobility.Above all,different environmental conditions and genetic differences between these two turtles produce significantly different plastron shapes.Using sexually dimorphic morphology measurements in multivariate statistical analysis showed: two Canonical discriminant functions,based on canonical discriminant function score draw scatter plots can be Hainan Four Eye-spotted turtle and Four Eye-spotted turtle and Sacalia bealei were completely separated,and discriminant function of each is 100% correct.Principal component analysis also confirms that each species has its unique species centroid,reflecting morphological differences.Using digital image analysis methods to study Hainan Four Eye-spotted turtle and Four Eye-spotted turtle plastron morphological differences:In order to study the taxonomic status of the Hainan Four Eye-spotted turtle(Sacalia insulensis),restricted to Hainan island,86 adult Four Eye-spotted turtles from three regions(Hainan,Guangxi and Guangdong)were analyzed in terms of morphological variation using digital image analysis.The results show that the number of black dots on the male Hainan Four eye-spotted turtle plastron is greater than the number of black dots on female turtles' plastrons,and the relative area ratio of female Hainan Four Eye-spotted turtle plastrons covered by black patches is greater than that of the males.Six angle values formed by plastron landmarks were measured,ANOVA showed that female Four Eye-spotted turtles and Hainan Four Eye-spotted turtles' plastron angularity was significantly different,except for ?4;males' plastron angles were significantly different except for ?2 and ?4.Using plastron angle Canonical discriminant analysis showed that Hainan Four Eye-spotted turtles are distinguishable from these of other regions of Southeast Asia,and that each group has its own species centroid.The shape of Hainan Four Eye-spotted turtle plastrons is significantly different from other Four Eye-spotted turtles.Results are consistent using plastron angle principal component analysis and Canonical discriminant analysis.Plastron morphological differences between Hainan Four Eye-spotted turtles and mainland Four Eye-spotted turtles support the hypothesis that they are two Sacalia species.Long-term geographical isolation and genetic differences are accountable for the evolution of these morphological differences which should be recognized to enhance conservation and avoidance of genetic cross-contamination respectively.Based on the above results it can be concluded: there are significant differences in body shape and carapace markings between Four Eye-spotted turtles and Hainan Four Eye-spotted turtles.Morphological analysis results support the Hainan Four Eye-spotted turtle as an independent species.This study explores the taxonomic status and identification of the Hainan Four Eye-spotted turtle on the basis of morphological evidence and proposed to Hainan Four eye-spotted turtle name by Sacalia insulensis instead Sacalia hainanensis.This paper evaluates the morphological differences between populations of superficially similar turtles using the first application of digital image processing software(IMP morphometric software)and the punctuation(landmark)concept,with a goal of quantifying morphological differences for reference value.