Abstract: Only recently Anuran fauna of Iran has been studied systematically. In order to study the biosystematics of Anuran in the Markazy Province, 122 specimens were collected from six stations during spring and summer 2004-2005. Samples were transferred alive to the zoology laboratory, identified and were preserved. The samples composed of the marsh frog, Rana ridibunda and the green toad, Bufo viridis. The phenetic studies between populations of the two species, 14 characteristics in frog and 17 characteristics in toad were measured. T-test analysis between sexes were significant in 12 characteristics for frogs and only one characteristic for toads (p<0.001). One way ANOVA between populations for each species were significant in 13 characteristics for frogs and 6 characteristics for toads (p<0.001). Difference between multivariate mean vectors confirmed in T2 Hotelling for populations and sexes of marsh frog (p<0.001). Length of foot and femur were discriminated distinct sexes based on discrimination analysis with 89% correct grouping for frogs and space between eyelids with 92% correct grouping for toads. Discrimination analysis between populations discriminated groups based on two functions with 78% correct grouping in frogs and 88% correct grouping in toads. Cluster analysis based on centroids grouped populations resulted from geographical and ecological conditions.
INTRODUCTION
The development of vertebrates began in the water. Land was truly invaded when the amphibians moved on to it. Environmental factors are often more significant for them than for other vertebrate classes (Grzimek, 1986). Amphibian populations are declining in many part of the world (Blaustein et al., 1994; Blaustein and Kiesecker, 2002). The disappearance of frogs, toads and salamanders have been reported in areas of south, central and north America, Europe, Asia, Africa and Australia (Alford and Richards, 1999; Blaustin and Kiesecker, 2002). Because of significant in food chain and their potential for living sources, a worldwide decline of amphibians could have a huge impact on other organisms, including humans. Amphibians are integral components of many ecosystems, often constituting the major component of vertebrate biomass (Pounds and Crump, 1994).
Unfortunately Iran, a zoogeographically important country, lacks any recent, detailed survey of its amphibian fauna, except for the short review by Leviton et al. (1992) and Firouz (2005). Eighteen species of amphibians are known from Iran; these include seven salamander and 11 anurans (Baloch and Kamy, 1973). Anurans include a pelobatid (6%), a hylid (6%), six toads (33%) from three species groups and three ranids (17%) from two genera. However, karyological evidence demonstrate the occurrence of both diploid (Bufo viridis) and tetraploid (Bufo danatensis) species in the former Soviet Central Asia (Duellman, 2002). The majority (83%) of Iranian amphibians is composed of Palearctic elements. The northern (Southern Caspian Sea) and western (Urmia-Zagros) parts of Iran have a richer fauna than other parts. These differences might be explained by climatic or historical factors (Duellman, 1999, 2002). Since the Markazy Province is located in central Iran, it is important to identify its amphibian to compare with other parts of Iran such as Khorasan Province (Eastern Iran).
MATERIALS AND METHODS
Samples of males and females of Rana ridibunda and Bufo viridis
were collected from the Markazy Province of central Iran during spring and summer
2004-2005. For a survey of phenetic variation between populations of two species
14 characteristics in frogs and 17 characteristics in toads were measured (Table
1).
| Table 1: | Conventional characteristics in frog and toad |
SPSS software was used to compare Markazy province with the Khorasan province populations.
RESULTS
T-test analysis comparing males and females in the populations at Markazy and Khorasan demonstrated that populations of Bufo were separated only by the distance between the parotid glands (Pa.d), (p = 0.003). In Rana populations, means of characteristics between sexes were not significant for two characteristics, Diameter of Trympanum (D.T), (0.193) and distance of nostrils (N.d), (0.925).
For study the means of between sexes, T2 Hoteling analysis demonstrated that Rana ridibunda had sexual dimorphism (p = 0.000, F = 7.63) but Bufo viridis did not have sexual dimorphism (p = 0.08, F = 1.7). Difference between multivariate mean vectors confirmed in T2 Hotelling for population of male marsh frog (p = 0.000, F = 7.26) and female marsh frog (p = 0.000, F = 5.48). For population of green toad (p = 0.000, F = 9). Principle Component Analysis (PCA), in male marsh frog population, exploited 2 means components (p1 = 9.2, p2 = 1.17). That first component expressed 66.3% changes and second component 8% changes.
Dispersion of specimen based upon 2 first components showed that Markazy and Khorasan populations were separated by first component (Fig. 1). Length of body (L), Tibia (T), Femur (F), head (L.C) and length of Foot (L.F) characteristics had the most effect on first component.
Discrimination analysis in male marsh frog exploited 4 means functions. Dispersion of male populations based upon first and second function showed that Markazy and Khorasan populations were separated by function 1 (Fig. 2). Length of Tibia (T) and Femur (F), had the most effect on function 1. Therefore base upon scale, in Khorasan province populations, Length of Tibia (T) and Femur (F) were longer than Markazy populations.
Cluster analysis based on centroids demonstrated that Markazy and Khorasan populations fall into two separate groups (Fig. 3).
Statistical analysis of female Rana ridibunda produced a similar result
to males.
| Fig. 1: | PCA Dispersion of male Rana ridibunda |
| Fig. 2: | Dispersion of male Rana ridibunda based on function 1, 2 |
| Fig. 3: | Dendrogram of male Rana ridibunda (1-5, Markazy province and 6-9, Khorasan province) |
Principle component analysis (PCA), in green toad populations, exploited 4 means components (p1 = 10.28, p2 = 2.19, p3 = 0.73, p4 = 0.67).
Dispersion of specimens based on 2 first components showed that Markazy and Khorasan populations were separated by component 1 (Fig. 4). Length of body (L), length of Foot (L.F) and length of Parotid glands (L.Pa), characteristics had the most effect on first component.
Discrimination analysis in green toad populations exploited 4 means functions.
Populations dispersion based on first and second function showed that Markazy
and Khorasan populations were separated by function 1 (Fig. 5).
Length of Parotid glands (L.Pa), had the most effect on function 1. Therefore
based upon scale, in Khorasan province populations, the length of parotid glands
(L.Pa) was longer than Markazy populations.
| Fig. 4: | PCA dispersion of Bufo viridis |
| Fig. 5: | Dispersion of Bufo viridis based on function 1,2 |
| Fig. 6: | Dendogram of Bufo viridis (1-5, Markazy province and 6-9, Khorasan province) |
Cluster analysis based on centroids demonstrated that Markazy and Khorasan populations fell into two separate groups (Fig. 6).
DISCUSSION
ANOVA analysis conventional characteristic of the marsh frog (Rana ridibunda) showed sexual dimorphism, which corresponded with the result of previous research done in Khorasan province Fakharzadeh (2003), Nematy (1998) and Molavi (2000). Multivariate analysis showed separation of Khorasan populations and Markazy province. This study demonstrated that length of Femur (F) and length of body (L), have more variety between populations. The causes could be ecological conditions and genetic differences. The grouping of Bufo viridis populations in multivariate analysis was more significant than Rana ridibunda populations. This could be caused by Parotid glands features that have the most variety among populations.