Ana Perera

Relationships between head morphology, bite performance and ecology in two species of Podarcis wall lizards

Understanding the relationship between form and function is central to our comprehension of how phenotypic diversity evolves. Traits involved in multiple activities, such as social interactions and ecological resource use, are under the influence of different evolutionary forces potentially acting in opposite directions. Such systems provide the opportunity of understanding how potential constraints on morphological variation may influence whole-organism performance. In this study we examined morphology and bite performance in two closely related species of Podarcis wall lizards with divergent microhabitat preferences, to investigate how natural and sexual selection interact to shape the evolution of head traits. Our results show that although head morphology is markedly different between species and sexes, only sexes differ in bite force, indicating that the ecological differentiation between species is reflected in their morphology but does not constrain performance. Rather, the modification of the relative size of head components between species and a shift in the form-function relationship provide a potential explanation of how equal performance is attained by different morphological configurations. Geometric morphometrics provide a clear, biomechanically meaningful image of how this is achieved and show a bisexual pattern of head shape-bite force association in both species. This, together with a strong allometry of head size on body size and head shape on head size, provides indirect morphological evidence for the importance of sexual selection in shaping morphological and functional patterns. Finally, our findings suggest that the differences observed between species and sexes in head traits and bite performance are not reflected in their dietary ecology, implying that if trophic niche segregation between groups occurs, the reasons behind it are not primarily related to head morphology and functional variation.

MOLECULAR CHARACTERIZATION OF HEPATOZOON SPECIES IN REPTILES FROM THE SEYCHELLES

Abstract Hepatozoon parasites were examined for the first time in reptiles from the Seychelles Islands. Although both prevalence and intensity were low, Hepatozoon species were detected in individuals from 2 endemic species, the lizard Mabuya wrightii and the snake Lycognathophis seychellensis. This was confirmed using visual identification and through sequencing part of the 18s rRNA gene. Phylogenetic analysis indicates that the Hepatozoon on the Seychelles form a monophyletic lineage, although more data are clearly needed to stabilize estimates of relationships based on this marker.

Molecular survey of Hepatozoon Species in Lizards From North Africa

Abstract The prevalence of Hepatozoon parasites in 460 lizards from North Africa was studied by amplification and sequencing of the 18S rRNA gene. The phylogenetic analysis of the 18S rRNA gene provides new insights into the phylogeny of these parasites with multiple genetically distinct lineages recovered. Parasite prevalence differed significantly between lacertid lizards and geckos. Our results show that there is limited host specificity and no clear relation to the geographical distribution of Hepatozoon parasites.

An integrative taxonomic revision of the Cape Verdean skinks (Squamata, Scincidae)

Miralles, A., Vasconcelos, R., Perera, A., Harris, D. J. & Carranza, S. (2010). An integrative taxonomic revision of the Cape Verdean skinks (Squamata, Scincidae). —Zoologica Scripta, 40, 16–44.

Genetic variability within the Oudri's fan-footed gecko Ptyodactylus oudrii in North Africa assessed using mitochondrial and nuclear DNA sequences

We analyse for the first time the genetic diversity within Ptyodactylus oudrii across the Maghreb. Two mitochondrial (12s rRNA and 16s rRNA) and two nuclear (C-mos and ACM4) markers are used. The results confirm the specific status of P. oudrii and show high levels of intraspecific variability, indicative of species complex. Lineages found are geographically concordant, and show similar patterns to that found in other species from the region. The study highlights once more the importance of the region as a source of genetic diversity.

A phylogenetic assessment of the colonisation patterns in Spauligodon atlanticus Astasio-Arbiza et al., 1987 (Nematoda: Oxyurida: Pharyngodonidae), a parasite of lizards of the genus Gallotia Boulenger: no simple answers

Parasite taxonomy traditionally relies on morphometric and life-cycle characteristics which may not reflect complex phylogenetic relationships. However, genetic analyses can reveal cryptic species within morphologically described parasite taxa. We analysed the phylogenetic variation within the nematode Spauligodon atlanticus Astasio-Arbiza, Zapatero-Ramos, Ojeda-Rosas & Solera-Puertas, 1987, a parasite of the Canarian lizard genus Gallotia Boulenger, inferring the origin of their current association. We also attempted to determine its relationship with other Spauligodon spp. Three different markers, mitochondrial COI plus nuclear 18S and 28S ribosomal RNA, were used to estimate the evolutionary relationships between these nematodes. S. atlanticus was found to be paraphyletic, suggesting that Gallotia spp. were colonised by two independent lineages of Spauligodon. Additional analyses of other Spauligodon spp. are required for a more complete interpretation of the evolution of this genus from the Canarian archipelago and its closest taxa. Our results emphasise the importance of extensive sampling and phylogenetic studies at the intrageneric level, and highlight the limitations of a morphologically based taxonomy in these parasites.

Molecular Survey of Apicomplexa In Podarcis Wall Lizards Detects Hepatozoon, Sarcocystis, and Eimeria Species

Abstract: The occurrence of apicomplexan parasites in Podarcis sp. wall lizards from the Iberian Peninsula and Balearic islands was studied by amplification and sequencing of the 18S rRNA gene. Species from 3 genera, Hepatozoon, Sarcocystis, and Eimeria, were found. The phylogenetic analysis of the 18S rRNA gene provides unexpected insights into the evolutionary history of these parasites. All Hepatozoon spp. specimens were recovered as part of a clade already identified in lizards from North Africa. The Sarcocystis species, detected in Podarcis lilfordi from Cabrera Island in the Balearic Islands, appears related to Sarcocystis gallotiae, known only from endemic Gallotia sp. lizards from the Canary Islands. Based on the lack of snake predators on this island, this parasite presumably presents an atypical transmission cycle that uses the same host species as both intermediate and final host through cannibalism, like S. gallotiae. Eimeria sp. is reported for the first time from Podarcis spp. lizards. This study shows the power of detecting multiple different apicomplexan parasites through screening of tail tissue samples and blood drops that are often collected in reptiles for other purposes.

A molecular phylogeny of the eastern group of ocellated lizard genus Timon (Sauria: Lacertidae) based on mitochondrial and nuclear DNA sequences

Timon, a small genus of lacertid lizards, includes four species distributed in two separate ranges in the western and eastern part of the Mediterranean Basin. Phylogenetic relationships between the two groups have not been resolved, and the taxonomic situation of the two subspecies of the eastern representative of the genus, Timon princeps, is not clear. To address these questions, partial DNA sequences of two nuclear (β-fibrinogen intron 7 and C-mos) and three mitochondrial (cytochrome b, 12S rRNA and 16S rRNA) genes were analyzed. Based on the high genetic distance between the two subspecies of T. princeps we promote their taxonomic status to full species, Timon princeps and Timon kurdistanicus. Divergence time estimates based on other lacertid species suggest that the separation of the green (Lacerta) and ocellated (Timon) lizards took place around 12 My ago, and that the Eastern group underwent speciation around 4-5 my ago, perhaps associated with the uplifting of the Zagros mountains. As expected given this ancient divergence and complex paleogeography, considerable levels of genetic diversity are recovered within both taxa, with geographically close individuals showing very divergent haplotypes.

Genetic diversity in the gecko Tarentola mauritanica within the Iberian Peninsula

The Mediterranean gecko Tarentola mauritanica is one of the most abundant reptile species in the western Mediterranean Basin. We use mitochondrial DNA sequences, 12sRNA and 16sRNA, to analyse the patterns of distribution in the Iberian Peninsula. The results show three well defined lineages. The first one, already known to be widespread throughout Europe, is distributed along the eastern coast and southern areas of the Iberian Peninsula. The second one, endemic to the Iberian Peninsula, is widely found in central regions; and the third lineage, found so far only in two southern localities is unrelated to the other Iberian lineages, but rather to a Northern Moroccan clade. The genetic variability found within the Iberian haplogroup and the existence of a single haplotype within the European lineage suggests a complex pattern of rapid radiations and anthropogenic introductions. The third clade seems to be the result of a natural colonization from North Africa. All the data indicate that T. mauritanica is a species complex. The Iberian Peninsula, due to its geological complex history, appears to be both a hotspot and a melting pot of biodiversity, with several studies of diverse herpetofauna indicating that cryptic species occur there. More studies of additional species will be needed to develop a comparative phylogeographic framework for the region.

Patterns of genetic diversity in Hepatozoon spp. infecting snakes from North Africa and the Mediterranean Basin

Species of Hepatozoon Miller, 1908 are blood parasites most commonly found in snakes but some have been described from all tetrapod groups and a wide variety of hematophagous invertebrates. Previous studies have suggested possible associations between Hepatozoon spp. found in predators and prey. Particularly, some saurophagous snakes from North Africa and the Mediterranean region have been found to be infected with Hepatozoon spp. similar to those of various sympatric lizard hosts. In this study, we have screened tissue samples of 111 North African and Mediterranean snakes, using specific primers for the 18S rRNA gene. In the phylogenetic analysis, the newly-generated Hepatozoon spp. sequences grouped separately into five main clusters. Three of these clusters were composed by Hepatozoon spp. also found in snakes and other reptiles from the Mediterranean Basin and North Africa. In the other two clusters, the new sequences were not closely related to geographically proximate known sequences. The phylogeny of Hepatozoon spp. inferred here was not associated with intermediate host taxonomy or geographical distribution. From the other factors that could explain these evolutionary patterns, the most likely seems series of intermediate hosts providing similar ribotypes of Hepatozoon and a high prevalence of host shifts for Hepatozoon spp. This is indicated by ribotypes of high similarity found in different reptile families, as well as by divergent ribotypes found in the same host species. This potentially low host specificity has profound implications for the systematics of Hepatozoon spp.