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Evolution of vipers and the role of key innovations in their diversification
Waldhauser, Vojtěch ; Šmíd, Jiří (advisor) ; Gvoždík, Václav (referee)
The family Viperidae consists of 36 genera, containing more than 350 species in total. The family is distributed throughout Africa and most of Eurasia, however the greatest diversity is located in North and South America, where more than 40 % of the viper species can be found. The family is thus missing only in Australia, New Guinea, Madagascar, New Zealand and a number of other islands and archipelagos. As with most reptiles, they are also almost completely absent from polar regions, with the exception of Vipera berus, the only snake that has ventured north of the Arctic Circle. Their relative evolutionary success is attributed to many so called "key innovations", which include solenoglyphous dentition, viviparity of many genera or heat- sensing pits in the subfamily Crotalinae. Vipers are not only interesting because of their evolutionary history, but they are also subject of important medical studies regarding their venom and toxicity. WHO estimates that around 100,000 people worldwide may die from snake bites each year. This thesis presents a summary of our current knowledge of the evolutionary history of this family, including phylogeny and biogeography, and contemplates the mechanisms behind its amazing diversity.
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Systematics, Phylogeny and Biogeography of the gecko genus Hemidactylus (Reptilia, Gekkonidae) in Arabia and the Near East.
Šmíd, Jiří ; Moravec, Jiří (advisor) ; Kotlík, Petr (referee) ; Rehák, Ivan (referee)
(in English) Until relatively recently, the gecko genus Hemidactylus was considered to contain only several hard-to-distinguish species in the eastern Mediterranean and the Arabian Peninsula. This was mostly given by the apparent morphological uniformity of the geckos in combination with their often synanthropic lifestyle, which facilitated the dispersal of some of the species over large ranges. However, our understanding of the diversity of the genus was about to change with the onset of molecular phylogenetic methods that became extensively available and routinely applied to tackle the questions of systematics and phylogeny of all kinds of organisms. This thesis focuses on resolving the phylogeny, systematics, and biogeography of the Arabian Hemidactylus. Using an unprecedented sampling of over 500 samples of more than 40 Hemidactylus species from the eastern Mediterranean, Arabian Peninsula, Socotra, North and East Africa and Iran and sequencing up to six genes (two mitochondrial - 12S rRNA, cyt b; four nuclear - cmos, mc1r, rag1, rag2) I reconstructed the time-calibrated phylogeny of the arid clade of Hemidactylus, inferred its complex biogeographical history in the region, and detected seven potentially new species. The results of the biogeographic analyses indicate that the current...
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Climatic determinates of elevation ranges in tropical vertebrates
Vobořilová, Kateřina ; Hořák, David (advisor) ; Šmíd, Jiří (referee)
Tropical regions are amongst the most diverse ecosystems on Earth. The significant species richness of these ecosystems is evident in the number of vertebrate species due to their distribution along altitudinal gradients. The distribution of vertebrates throughout altitudinal gradients is a natural phenomenon by which vertebrates respond to diverse abiotic conditions. Together with the geographic distribution of mountains, biotic influences, thermal physiology of individual vertebrate groups or climatic changes, these abiotic conditions create specific conditions for vertebrates. All of these factors may contribute to the spread of vertebrates to lower or higher altitudes. They may also influence altitudinal migration, depending on the adaptation of individual vertebrate species. In this thesis I focused on how individual abiotic determinants such as temperature, precipitation and air humidity, as well as climatic changes, can positively or negatively influence the distribution ranges of four vertebrate groups along elevational gradients of tropical mountains. Keywords: temperature, precipitation, cloudiness, tropics, elevation, geographical distribution, species richness
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Systermatics and biogeography of the genus Platyceps with special emphasis on the Middle Eastern species
Velenská, Doubravka ; Šmíd, Jiří (advisor) ; Rehák, Ivan (referee)
The colubrids genus Platyceps has been included in several phylogenetic studies of the family Colubridae, however the phylogenetic relationships between its species still remain unresolved. The major problem is an insufficient coverage of species in genetic analyses. In this study, I analyse 90 specimens of fourteen Platyceps species to shed more light on the evolutionary history of the genus. Some of the species have never been included in such a genetic analysis before. The phylogeny is based on a combination of four mitochondrial (12S rRNA, cytb, COI, ND4) and two nuclear (cmos, NT3) markers. My results confirm the genus as monophyletic and divide it in to three major clades - the Indian clade (P. bholanathi, P. gracilis, P. ladacensis, P. ventromaculatus a P. sp_central_asia), the West Asian clade (P. karelini, P. rogersi, P. saharicus a P. rhodorachis) and the Dispersive clade (P. plinii, P. josephi, P. florulentus, P. taylori, P. najadum, P. collaris, P. elegantissimus, P. manseri, P. sinai, P. variabilis). According to the results, the phylogenetic positions of several species differ considerably compared to previously published studies. The species Platyceps thomasi appears to be just a colour morph variation of Platyceps variabilis. Platyceps variabilis manseri, on the other hand, emerges...
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Phylogeography of the Bunopus geckos (Squamata, Gekkonidae) in the Arabian Peninsula
Pola, Lukáš ; Šmíd, Jiří (advisor) ; Rehák, Ivan (referee)
The Arabian Peninsula represents a bridge between three continents and two major zoogeographic regions, the Palearctic and Afrotropical (Ethiopian). It is well known for its richness and endemicity not only among geckos, but among squamate reptiles in general. Besides impressive endemic species located in the mountains, there are some, widely distributed across the entire Arabian Peninsula (pan-arabian distribution) and in terms of research they remain neglected. Among Arabian geckos, the genus Bunopus are an excellent example, whose systematics and taxonomy are quite problematic, albeit they are distributed across the entire peninsula. In order to answer the question of possible cryptic diversity of these geckos in the Arabian Peninsula, phylogenetic position of more than 80 samples covering the vast part of their distribution range has been reconstructed based on two mitochondrial (12S rRNA and COI) and two nuclear markers (RAG2 and c-mos). Haplotype networks were reconstructed from nuclear markers in order to show genealogical relationships. Results of the phylogenetic analyses presented herein show that cryptic diversity in the Arabian Peninsula is smaller in comparison to the one that was uncovered in the Iranian Plateau. Almost entire Arabian Peninsula is inhabited by two lineages only, which...
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Phylogeny, diversification dynamics and biogeography of Hemidactylus geckos
Janák, Vojtěch ; Šmíd, Jiří (advisor) ; Kratochvíl, Lukáš (referee)
Hemidactylus is the second-most speciose among all gekkotan genera and also accounts very well for most typical characteristics of the group, such as almost worldwide distribution and significant species diversity. Many new species have been described in recent years, doubling the over all species count. Although the amout of knowledge regarding this genus has grown significantly, there is still some confusion in the matter of clade relationships on high as well as low levels of phylogeny. This thesis aims to summarize current knowledge of phylogeny and biogeography of this genus and its subclades.
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Modelling of Transport Systems
Šmíd, Jiří ; Martinek, David (referee) ; Peringer, Petr (advisor)
The presented work describes both transportation and traffic flow simulation. For that purpose two different libraries were made. The first one is based on an existing library, Simlib/C++. For the traffic flow simulation a brand new library was created, using cellular automaton rules. Above all, it is designed to facilitate analysis of fundamental attributes of traffic network. Vehicles varying in size are able to find their own route plans from point where they were generated. Both libraries offer users a large amount of flexibility in specifying transport and traffic network.
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Phylogeny and biogeography of whipsnakes of the genus Platyceps (Squamata, Colubridae)
Velenská, Doubravka ; Šmíd, Jiří (advisor) ; Smolinský, Radovan (referee)
The genus Platyceps belongs to family Colubridae, order Squamata, and contains 26 species. It is characterized by slender body, flat head and tail which is not longer than a sixth of the total body length. The distribution of the genus is quite large, it contains Saharo-Sindian biogeographic region which spans from North Africa to East Asia and contains also the area of the Mediterranean Sea and East Africa. The phylogeny of genus Platyceps is unclear. Even thought there have been efforts to untangle it, the genetics-based studies had a limited material available (no study contains all the known species). Moreover, the taxa, especially from the P. rhodorachis-ventromaculatus species complex, are morphologically similar and they be easily mistaken. Another problem is that descriptions of new species are not put in the context of the entire genus, different authors use different names for the same taxon, and most descriptions has been based solely on morphology. The genus was divided into three groups. This division is however based on morphology and biogeography and genetic studies do not always support it.
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Evolution of sex determination and sex chromosomes in snakes
Charvát, Tomáš ; Kratochvíl, Lukáš (advisor) ; Šmíd, Jiří (referee)
Snakes form with almost 3700 described species more than one third of all squamate reptiles. The vast majority of snake species belong to the group Caenophidia, which is the best explored group of snakes for sex chromosomes. In contrast, sex chromosomes of the two other groups of snakes - Scolecophidia and Henophidia have so far been paid little attention. All snakes studied so far possess genotypic sex determination. Representatives of all Caenophidian families were observed with a female heterogamety sex determination system (ZZ/ZW) and it was widely accepted that this system was common to all snakes. This claim was recently refuted when a male heterogamety (XX/XY) was confirmed in a python (Python bivittatus) and a boa (Boa imperator), two representatives of Henophidia. In Henophidia, besides the XX/XY system, the ZZ/ZW system was reported in the only known representative of this group with heteromorphic sex chromosomes - A. sp. cf. dumerili. Sex chromosomes or sex determination systems are unknown in Scolecophidia. Caenophidian heteromorphic sex chromosomes have enabled the study of the phenomena associated with the gradual differentiation of sex chromosomes. These include W chromosome degeneration, the accumulation of repetitive elements, the fast Z phenomena, gene dosage compensation, and...
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