Bill Brooks is worried about the future of his organization, perhaps even more than he is about the future of horned lizards. Brooks is the president and a founding member of the Horned Lizard Conservation Society, a nonprofit with the goal of protecting all species of horned lizard. The HLCS was founded in Austin in 1991, after its members realized that populations of Texas horned lizards, Phrynosoma cornutum, had crashed at some point in the preceding decades; they wanted to both figure out what had happened to the lizards and how to bring them back. Cornutum is an iconic species and the state reptile, and almost all Texans over the age of 40 can remember seeing them in the hundreds as children. Flash-forward a quarter of a century, and a lot of these founding members are either old and grey or deceased. HLCS membership is down, and Brooks thinks that if there aren’t any of his kind left (Texans that grew up with “horny toads”), there’ll be no one left to care. Herpetologists are working on returning healthy horned lizard populations to the wild, and both reintroduction and relocation programs are showing signs of success. But can they work, and will it be too late for Brooks’ organization and a Texas identity dependent upon horned lizards? / text

Calcified teeth comprise the hardest vertebrate tissues (enamel and dentine) and they undoubtedly represent a key evolutionary advantage for their users. Nevertheless, teeth have been lost many times and they were often replaced by keratinised structures, such as rhamphoteca of birds or of turtle beaks, or labial tooth structures and scratching laminae of many aquatic vertebrates. This thesis is intended to analyse levels of similarities among keratinised teeth and structures of three phylogenetically distinct lineages of amniotes and to compare them to morphogenesis of true teeth. Detailed developmental and structural characteristics of oral apparatus possessing keratinous teeth of lampreys, Loricarid cathfishes and frog tadpoles were identified and distinguished. Keratinous structures of cathfishes include only horny projections from single cell surface (unculi), whereas in frog tadpoles both horny jaw sheet and unicellular labial teeth composed by cell columns were found; the lamprey oral apparatus consists of multicellular teeth and laminae instead. Disparate phenotypes of these keratinous structures can, however, developmentally derive from a general process of keratinization: morphological disparities arise by distinct gradual accretion of keratinous layers and collumns during development. My...