<i>Darevskia</i> Arribas, 1997 The name <i>Darevskia</i> became officiall... more <i>Darevskia</i> Arribas, 1997 The name <i>Darevskia</i> became officially public in 1999 (Arribas 1999), but it was first used in an unpublished PhD thesis by the same author handed in 1997, and as such should be referred to (Arribas, in litt.).
<i>Cyrtopodion</i> Fitzinger, 1843 A relatively species-rich genus (26 species; Uetz ... more <i>Cyrtopodion</i> Fitzinger, 1843 A relatively species-rich genus (26 species; Uetz 2013) that previously encompassed also members of <i>Mediodactylus</i> and <i>Tenuidactylus</i>, in some studies treated as subgenera but currently recognized as distinct (see below). The Iranian species of <i>Cyrtopodion</i> (sensu stricto) were on the basis of morphological differentiation divided into two groups: the <i>agamuroides</i> group and the <i>scabrum</i> group (Szczerbak &amp; Golubev 1986; Anderson 1999). The <i>agamuroides</i> group currently contains five species: <i>C. agamuroides</i>, <i>C. gastropholis</i>, <i>C</i>. <i>golubevi</i>, <i>C. kiabii</i>, and <i>C. persepolense</i>; four species are known to belong to the <i>scabrum</i> group: <i>C. brevipes</i>, <i>C. kachhense</i>, <i>C. scabrum</i>, and <i>C. sistanense</i> (Nazarov &amp; Rajabizadeh 2007; Bauer <i>et al</i>. 2013). <i>Cyrtopodion hormozganum</i> was recognized as an intermediate form between the two groups (Nazarov <i>et al</i>. 2012), and the assignment of <i>C. kirmanense</i> is unknown.
Evolution; international journal of organic evolution, Jan 4, 2018
Snakes are historically important in the formulation of several central concepts on the evolution... more Snakes are historically important in the formulation of several central concepts on the evolution of sex chromosomes. For over 50 years, it was believed that all snakes shared the same ZZ/ZW sex chromosomes, which are homomorphic and poorly differentiated in "basal" snakes such as pythons and boas, while heteromorphic and well differentiated in "advanced" (caenophidian) snakes. Recent molecular studies revealed that differentiated sex chromosomes are indeed shared among all families of caenophidian snakes, but that boas and pythons evolved likely independently male heterogamety (XX/XY sex chromosomes). The historical report of heteromorphic ZZ/ZW sex chromosomes in a boid snake was previously regarded as ambiguous. In the current study, we document heteromorphic ZZ/ZW sex chromosomes in a boid snake. A comparative approach suggests that these heteromorphic sex chromosomes evolved very recently and that they are poorly differentiated at the sequence level. Interes...
This chapter summarizes research on sexual size dimorphism (SSD) in eye-lid geckos (Eublepharidae... more This chapter summarizes research on sexual size dimorphism (SSD) in eye-lid geckos (Eublepharidae) by integrating morphological, behavioural, and life-history data, and using phylogenetic analyses to determine which variable(s) may explain SSD. These comparisons reveal that male combat has disappeared twice within this family, and both events were associated with losses of male scent glands and male-biased head size dimorphism, which is consistent with the predictions of sexual selection theory. Evolutionary changes in male-male aggression, in the complexity of courtship display, or in relative egg size were not correlated with reversals from male-biased to female-biased SSD. Eublepharids demonstrate Rensch's rule, since in small species females tend to be larger whereas in large species males are larger. An explanation of this common allometric pattern will be necessary for a full understanding of SSD in this family.
Sand fly saliva has considerable immunomodulatory effects onLeishmaniainfections in mammalian hos... more Sand fly saliva has considerable immunomodulatory effects onLeishmaniainfections in mammalian hosts. Studies on severalLeishmania– sand fly - host combinations have demonstrated that co-inoculation withLeishmaniaparasites enhances pathogenicity, while pre-exposure of hosts to sand fly bites provides significant protection against infection. However, the third scenario, the effect of sand fly saliva on parasite development in hosts infected before exposure to sand flies, remains an understudied aspect ofLeishmania–host–vector interaction. Here we studied the effect of exposure ofL. major-infected BALB/c mice to repeated sand fly bites. Mice infected intradermally with sand fly-derivedLeishmaniawere repeatedly bitten byPhlebotomus duboscqifemales every two weeks. The lesion development was recorded weekly for ten weeks post-infection and parasite load and distribution in various organs were testedpost mortemusing qPCR. Repeated sand fly bites significantly enhanced the development of ...
<i>Darevskia steineri</i> (Eiselt, 1995) HOLOTYPE. NMW 33715. TYPE LOCALITY. Gole-Low... more <i>Darevskia steineri</i> (Eiselt, 1995) HOLOTYPE. NMW 33715. TYPE LOCALITY. Gole-Loweh near Minou-dasht, Golestan Prov. Iran. DISTRIBUTION. Endemic to Iran. DISTRIBUTION IN IRAN. Fig. 88. A small area in Golestan Prov. It was known only from the type specimens until Rastegar-Pouyani <i>et al.</i> (2013b) discovered a population about 35 km NE from the type locality. HABITAT. <i>Darevskia steineri</i> climbs trees and rocks in dense Hyrcanian forests consisting of <i>Acer</i> spp., <i>Alnus serrulata</i>, <i>Glechoma hederacea</i>, <i>Philodendron bipinnatifidum</i>, <i>Quercus castaneifolia</i>, <i>Rubus fruticosus</i>, and <i>Ruscus hurcanus</i> (Hosseinian Yousefkhani <i>et al.</i> 2013g; Rastegar-Pouyani <i>et al.</i> 2013b). REFERENCES. Eiselt (1995); Anderson (1999); Arnold <i>et al.</i> (2007); Ahmadzadeh <i>et al.</i> (2013a); Hosseinian Yousefkhani <i>et al.</i> (2013c); Rastegar-Pouyani <i>et al.</i> (2013b).
Secondary sex ratios of animals with genetically determined sex may considerably deviate from equ... more Secondary sex ratios of animals with genetically determined sex may considerably deviate from equality. These deviations may be attributed to several proximate and ultimate factors. Sex ratio theory explains some of them as strategic decisions of mothers improving their fitness by selective investment in sons or daughters, e.g. local resource competition hypothesis (LRC) suggests that philopatric females tend to produce litters with male-biased sex ratios to avoid future competition with their daughters. Until now, only little attention has been paid to examine predictions of sex ratio theory in snakes possessing genetic sex determination and exhibiting large variance in allocation of maternal investment. Cuban boa is an endemic viviparous snake producing large-bodied newborns (∼200 g). Extremely high maternal investment in each offspring increases importance of sex allocation. In a captive colony, we collected breeding records of 42 mothers, 62 litters and 306 newborns and examined secondary sex ratios (SR) and sexual size dimorphism (SSD) of newborns. None of the examined morphometric traits of neonates appeared sexually dimorphic. The sex ratio was slightly male biased (174 males versus 132 females) and litter sex ratio significantly decreased with female snout-vent length. We interpret this relationship as an additional support for LRC as competition between mothers and daughters increases with similarity of body sizes between competing snakes.
Animal species are delimited by reproductive isolation mechanisms (RIMs). Postzygotic RIMs are ma... more Animal species are delimited by reproductive isolation mechanisms (RIMs). Postzygotic RIMs are mainly products of genetic differences and thus their strength increases with elapsed divergence time. The relationship between postzygotic reproductive isolation and genetic divergence, however, differs considerably among major clades of vertebrates. We reviewed the available literature providing empirical evidence of natural and/or experimental hybridization between distinct species of lizards (squamates except snakes). We found that hybridization events are widely distributed among nearly all major lizard clades. The majority of research focuses on parthenogenetic species and/or polyploid hybrids in families Lacertidae, Teiidae and Gekkonidae. Homoploid bisexual hybrids are mainly reported within Lacertidae and Iguania groups. As a proxy of genetic divergence of the hybridizing taxa we adopted nucleotide sequence distance (HKY85) of mitochondrial cyt b gene. The upper limit of genetic d...
Social organization of many reptile species that are rare in the wild remains rather unexplored d... more Social organization of many reptile species that are rare in the wild remains rather unexplored due to difficulties when setting experiments in the field. Behavioral analysis of standard social situations in laboratory conditions is considered an indirect method to reveal social behavior in the field. We studied two rare species of geckos, Teratoscincus scincus and Teratoscincus keyserlingii, inhabiting sand dunes of Uzbekistan and Eastern Iran. A series of experiments was carried out to quantify responses in social interactions among conspecific adults as well as reactions of these towards conspecific/heterospecific subadults and juveniles. We also assessed the effect of species and sex on recorded behavior. Finally, the reaction to threat stimuli simulating predator attack was analyzed. The species effect was recorded only in the response to a simulated predatory attack: T. scincus typically escaped whereas larger T. keyserlingii attacked the stimulus. In accordance with the sexual competition hypothesis, agonistic interactions were nearly exclusively confined to male-male encounters while females were tolerant to each other. Male-female encounters regularly resulted in mating attempts, which suggests that females are not strongly selective in choosing partners. Therefore, male aggression can be linked to mate guarding or territoriality. Adults&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; lack of interest in immature geckos may indicate generalized tolerance of adults towards young.
Monitor lizards belong to the largest and the most sexually dimorphic lizards in terms of size, m... more Monitor lizards belong to the largest and the most sexually dimorphic lizards in terms of size, making this group an ideal model for studies analyzing ontogenetic causes of sexual dimorphism. Understanding of these ontogenetic factors is essential to the current discussion concerning patterns of sexual dimorphism in animals. We examined the ontogenetic trajectories of body weight and snout-vent length to analyze the emergence of sexual size dimorphism. Experimental animals were 22 males and 13 females of mangrove-dwelling monitors (Varanus indicus) hatched at the Prague Zoo. They were regularly weighed and measured up to the age of 33-40 months, and subsequently sexed by ultrasonographic imaging. The logistic growth equation was used to describe and analyze the observed growth patterns. Our results confirm considerable sexual size dimorphism in the mangrove monitor. The mean asymptotic body weight of males was nearly three times higher than that of females. As the body size of male and female hatchlings is almost equal, and the growth rate parameter (K) of the logistic growth equation as well as the absolute growth rate up to the age of 12 months do not differ between the sexes, size differences between fully grown males and females should be attributed to timing of the postnatal growth. Males continue to grow several months after they reach the age when the growth of females is already reduced. Therefore, the sexual size dimorphism emerges and sharply increases at this period.
Page 1. ISRAEL JOURNAL OF ECOLOGY AND EVOLUTION, Vol. 52, 2006, pp. 151158 *Author to whom corre... more Page 1. ISRAEL JOURNAL OF ECOLOGY AND EVOLUTION, Vol. 52, 2006, pp. 151158 *Author to whom correspondence should be addressed. E-mail: frynta@centrum.cz Accepted 5 November 2006. NOTE: HAVE BLACK ...
ABSTRACT Cockroaches (Blattaria) are considered universally gregarious insects. In this study, we... more ABSTRACT Cockroaches (Blattaria) are considered universally gregarious insects. In this study, we tested the hypothesis that even related species and/or males and females of the same species may exhibit different aggregation patterns. We compared aggregation behaviour in six cockroach species belonging to three groups: Eublaberus, Blaberus, and Gromphadorhina-Princisia (all Blaberidae). For comparison, binary choice and free aggregation arena tests were used. The results revealed that blaberid clades clearly differed in their aggregation patterns. Females of Eublaberus species aggregated, whereas only a low aggregation tendency was recorded in conspecific males. Both sexes of Blaberus species aggregated, especially when tested in the arena. The Madagascar hissing cockroaches of the Gromphadorhina-Princisia clade are not gregarious – the aggregation tendency was entirely absent in males of the two species studied and in females of Princisia vanwaerebeki van Herrewege, and was only weakly demonstrated in females of Gromphadorhina portentosa (Schaum). The observed patterns of aggregation are compared with previous reports concerning social behaviour of blaberid species.
In monitor lizards, males are typically larger than conspecific females, but body shape is usuall... more In monitor lizards, males are typically larger than conspecific females, but body shape is usually quite similar in both sexes. This not only represents a puzzle worthy of evolutionary explanation, but also makes field sex determination of monitor lizards difficult. We asked whether subtle differences in body shape follow the same pattern as in other sexually dimorphic lizard taxa and thus can be explained by the same selective forces. We tested the hypotheses that (1) females have a longer abdomen due to fecundity selection and (2) males possess bigger heads due to intrasexual selection. We also hypothesised that (3) male monitors show a wider chests and longer upper fore-limbs to win male-male wrestling matches. We monitored ontogeny in 35 mangrove-dwelling monitors (Varanus indicus). Seventeen body measurements were taken every three months up to the age of 24-34 months. Sex was determined by an ultrasonographic imaging. We employed multiple approaches to remove the effect of siz...
<i>Darevskia</i> Arribas, 1997 The name <i>Darevskia</i> became officiall... more <i>Darevskia</i> Arribas, 1997 The name <i>Darevskia</i> became officially public in 1999 (Arribas 1999), but it was first used in an unpublished PhD thesis by the same author handed in 1997, and as such should be referred to (Arribas, in litt.).
<i>Cyrtopodion</i> Fitzinger, 1843 A relatively species-rich genus (26 species; Uetz ... more <i>Cyrtopodion</i> Fitzinger, 1843 A relatively species-rich genus (26 species; Uetz 2013) that previously encompassed also members of <i>Mediodactylus</i> and <i>Tenuidactylus</i>, in some studies treated as subgenera but currently recognized as distinct (see below). The Iranian species of <i>Cyrtopodion</i> (sensu stricto) were on the basis of morphological differentiation divided into two groups: the <i>agamuroides</i> group and the <i>scabrum</i> group (Szczerbak &amp; Golubev 1986; Anderson 1999). The <i>agamuroides</i> group currently contains five species: <i>C. agamuroides</i>, <i>C. gastropholis</i>, <i>C</i>. <i>golubevi</i>, <i>C. kiabii</i>, and <i>C. persepolense</i>; four species are known to belong to the <i>scabrum</i> group: <i>C. brevipes</i>, <i>C. kachhense</i>, <i>C. scabrum</i>, and <i>C. sistanense</i> (Nazarov &amp; Rajabizadeh 2007; Bauer <i>et al</i>. 2013). <i>Cyrtopodion hormozganum</i> was recognized as an intermediate form between the two groups (Nazarov <i>et al</i>. 2012), and the assignment of <i>C. kirmanense</i> is unknown.
Evolution; international journal of organic evolution, Jan 4, 2018
Snakes are historically important in the formulation of several central concepts on the evolution... more Snakes are historically important in the formulation of several central concepts on the evolution of sex chromosomes. For over 50 years, it was believed that all snakes shared the same ZZ/ZW sex chromosomes, which are homomorphic and poorly differentiated in "basal" snakes such as pythons and boas, while heteromorphic and well differentiated in "advanced" (caenophidian) snakes. Recent molecular studies revealed that differentiated sex chromosomes are indeed shared among all families of caenophidian snakes, but that boas and pythons evolved likely independently male heterogamety (XX/XY sex chromosomes). The historical report of heteromorphic ZZ/ZW sex chromosomes in a boid snake was previously regarded as ambiguous. In the current study, we document heteromorphic ZZ/ZW sex chromosomes in a boid snake. A comparative approach suggests that these heteromorphic sex chromosomes evolved very recently and that they are poorly differentiated at the sequence level. Interes...
This chapter summarizes research on sexual size dimorphism (SSD) in eye-lid geckos (Eublepharidae... more This chapter summarizes research on sexual size dimorphism (SSD) in eye-lid geckos (Eublepharidae) by integrating morphological, behavioural, and life-history data, and using phylogenetic analyses to determine which variable(s) may explain SSD. These comparisons reveal that male combat has disappeared twice within this family, and both events were associated with losses of male scent glands and male-biased head size dimorphism, which is consistent with the predictions of sexual selection theory. Evolutionary changes in male-male aggression, in the complexity of courtship display, or in relative egg size were not correlated with reversals from male-biased to female-biased SSD. Eublepharids demonstrate Rensch's rule, since in small species females tend to be larger whereas in large species males are larger. An explanation of this common allometric pattern will be necessary for a full understanding of SSD in this family.
Sand fly saliva has considerable immunomodulatory effects onLeishmaniainfections in mammalian hos... more Sand fly saliva has considerable immunomodulatory effects onLeishmaniainfections in mammalian hosts. Studies on severalLeishmania– sand fly - host combinations have demonstrated that co-inoculation withLeishmaniaparasites enhances pathogenicity, while pre-exposure of hosts to sand fly bites provides significant protection against infection. However, the third scenario, the effect of sand fly saliva on parasite development in hosts infected before exposure to sand flies, remains an understudied aspect ofLeishmania–host–vector interaction. Here we studied the effect of exposure ofL. major-infected BALB/c mice to repeated sand fly bites. Mice infected intradermally with sand fly-derivedLeishmaniawere repeatedly bitten byPhlebotomus duboscqifemales every two weeks. The lesion development was recorded weekly for ten weeks post-infection and parasite load and distribution in various organs were testedpost mortemusing qPCR. Repeated sand fly bites significantly enhanced the development of ...
<i>Darevskia steineri</i> (Eiselt, 1995) HOLOTYPE. NMW 33715. TYPE LOCALITY. Gole-Low... more <i>Darevskia steineri</i> (Eiselt, 1995) HOLOTYPE. NMW 33715. TYPE LOCALITY. Gole-Loweh near Minou-dasht, Golestan Prov. Iran. DISTRIBUTION. Endemic to Iran. DISTRIBUTION IN IRAN. Fig. 88. A small area in Golestan Prov. It was known only from the type specimens until Rastegar-Pouyani <i>et al.</i> (2013b) discovered a population about 35 km NE from the type locality. HABITAT. <i>Darevskia steineri</i> climbs trees and rocks in dense Hyrcanian forests consisting of <i>Acer</i> spp., <i>Alnus serrulata</i>, <i>Glechoma hederacea</i>, <i>Philodendron bipinnatifidum</i>, <i>Quercus castaneifolia</i>, <i>Rubus fruticosus</i>, and <i>Ruscus hurcanus</i> (Hosseinian Yousefkhani <i>et al.</i> 2013g; Rastegar-Pouyani <i>et al.</i> 2013b). REFERENCES. Eiselt (1995); Anderson (1999); Arnold <i>et al.</i> (2007); Ahmadzadeh <i>et al.</i> (2013a); Hosseinian Yousefkhani <i>et al.</i> (2013c); Rastegar-Pouyani <i>et al.</i> (2013b).
Secondary sex ratios of animals with genetically determined sex may considerably deviate from equ... more Secondary sex ratios of animals with genetically determined sex may considerably deviate from equality. These deviations may be attributed to several proximate and ultimate factors. Sex ratio theory explains some of them as strategic decisions of mothers improving their fitness by selective investment in sons or daughters, e.g. local resource competition hypothesis (LRC) suggests that philopatric females tend to produce litters with male-biased sex ratios to avoid future competition with their daughters. Until now, only little attention has been paid to examine predictions of sex ratio theory in snakes possessing genetic sex determination and exhibiting large variance in allocation of maternal investment. Cuban boa is an endemic viviparous snake producing large-bodied newborns (∼200 g). Extremely high maternal investment in each offspring increases importance of sex allocation. In a captive colony, we collected breeding records of 42 mothers, 62 litters and 306 newborns and examined secondary sex ratios (SR) and sexual size dimorphism (SSD) of newborns. None of the examined morphometric traits of neonates appeared sexually dimorphic. The sex ratio was slightly male biased (174 males versus 132 females) and litter sex ratio significantly decreased with female snout-vent length. We interpret this relationship as an additional support for LRC as competition between mothers and daughters increases with similarity of body sizes between competing snakes.
Animal species are delimited by reproductive isolation mechanisms (RIMs). Postzygotic RIMs are ma... more Animal species are delimited by reproductive isolation mechanisms (RIMs). Postzygotic RIMs are mainly products of genetic differences and thus their strength increases with elapsed divergence time. The relationship between postzygotic reproductive isolation and genetic divergence, however, differs considerably among major clades of vertebrates. We reviewed the available literature providing empirical evidence of natural and/or experimental hybridization between distinct species of lizards (squamates except snakes). We found that hybridization events are widely distributed among nearly all major lizard clades. The majority of research focuses on parthenogenetic species and/or polyploid hybrids in families Lacertidae, Teiidae and Gekkonidae. Homoploid bisexual hybrids are mainly reported within Lacertidae and Iguania groups. As a proxy of genetic divergence of the hybridizing taxa we adopted nucleotide sequence distance (HKY85) of mitochondrial cyt b gene. The upper limit of genetic d...
Social organization of many reptile species that are rare in the wild remains rather unexplored d... more Social organization of many reptile species that are rare in the wild remains rather unexplored due to difficulties when setting experiments in the field. Behavioral analysis of standard social situations in laboratory conditions is considered an indirect method to reveal social behavior in the field. We studied two rare species of geckos, Teratoscincus scincus and Teratoscincus keyserlingii, inhabiting sand dunes of Uzbekistan and Eastern Iran. A series of experiments was carried out to quantify responses in social interactions among conspecific adults as well as reactions of these towards conspecific/heterospecific subadults and juveniles. We also assessed the effect of species and sex on recorded behavior. Finally, the reaction to threat stimuli simulating predator attack was analyzed. The species effect was recorded only in the response to a simulated predatory attack: T. scincus typically escaped whereas larger T. keyserlingii attacked the stimulus. In accordance with the sexual competition hypothesis, agonistic interactions were nearly exclusively confined to male-male encounters while females were tolerant to each other. Male-female encounters regularly resulted in mating attempts, which suggests that females are not strongly selective in choosing partners. Therefore, male aggression can be linked to mate guarding or territoriality. Adults&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; lack of interest in immature geckos may indicate generalized tolerance of adults towards young.
Monitor lizards belong to the largest and the most sexually dimorphic lizards in terms of size, m... more Monitor lizards belong to the largest and the most sexually dimorphic lizards in terms of size, making this group an ideal model for studies analyzing ontogenetic causes of sexual dimorphism. Understanding of these ontogenetic factors is essential to the current discussion concerning patterns of sexual dimorphism in animals. We examined the ontogenetic trajectories of body weight and snout-vent length to analyze the emergence of sexual size dimorphism. Experimental animals were 22 males and 13 females of mangrove-dwelling monitors (Varanus indicus) hatched at the Prague Zoo. They were regularly weighed and measured up to the age of 33-40 months, and subsequently sexed by ultrasonographic imaging. The logistic growth equation was used to describe and analyze the observed growth patterns. Our results confirm considerable sexual size dimorphism in the mangrove monitor. The mean asymptotic body weight of males was nearly three times higher than that of females. As the body size of male and female hatchlings is almost equal, and the growth rate parameter (K) of the logistic growth equation as well as the absolute growth rate up to the age of 12 months do not differ between the sexes, size differences between fully grown males and females should be attributed to timing of the postnatal growth. Males continue to grow several months after they reach the age when the growth of females is already reduced. Therefore, the sexual size dimorphism emerges and sharply increases at this period.
Page 1. ISRAEL JOURNAL OF ECOLOGY AND EVOLUTION, Vol. 52, 2006, pp. 151158 *Author to whom corre... more Page 1. ISRAEL JOURNAL OF ECOLOGY AND EVOLUTION, Vol. 52, 2006, pp. 151158 *Author to whom correspondence should be addressed. E-mail: frynta@centrum.cz Accepted 5 November 2006. NOTE: HAVE BLACK ...
ABSTRACT Cockroaches (Blattaria) are considered universally gregarious insects. In this study, we... more ABSTRACT Cockroaches (Blattaria) are considered universally gregarious insects. In this study, we tested the hypothesis that even related species and/or males and females of the same species may exhibit different aggregation patterns. We compared aggregation behaviour in six cockroach species belonging to three groups: Eublaberus, Blaberus, and Gromphadorhina-Princisia (all Blaberidae). For comparison, binary choice and free aggregation arena tests were used. The results revealed that blaberid clades clearly differed in their aggregation patterns. Females of Eublaberus species aggregated, whereas only a low aggregation tendency was recorded in conspecific males. Both sexes of Blaberus species aggregated, especially when tested in the arena. The Madagascar hissing cockroaches of the Gromphadorhina-Princisia clade are not gregarious – the aggregation tendency was entirely absent in males of the two species studied and in females of Princisia vanwaerebeki van Herrewege, and was only weakly demonstrated in females of Gromphadorhina portentosa (Schaum). The observed patterns of aggregation are compared with previous reports concerning social behaviour of blaberid species.
In monitor lizards, males are typically larger than conspecific females, but body shape is usuall... more In monitor lizards, males are typically larger than conspecific females, but body shape is usually quite similar in both sexes. This not only represents a puzzle worthy of evolutionary explanation, but also makes field sex determination of monitor lizards difficult. We asked whether subtle differences in body shape follow the same pattern as in other sexually dimorphic lizard taxa and thus can be explained by the same selective forces. We tested the hypotheses that (1) females have a longer abdomen due to fecundity selection and (2) males possess bigger heads due to intrasexual selection. We also hypothesised that (3) male monitors show a wider chests and longer upper fore-limbs to win male-male wrestling matches. We monitored ontogeny in 35 mangrove-dwelling monitors (Varanus indicus). Seventeen body measurements were taken every three months up to the age of 24-34 months. Sex was determined by an ultrasonographic imaging. We employed multiple approaches to remove the effect of siz...
Uploads
Papers by Daniel Frynta