Haemogregarines (Apicomplexa: Adeleorina) are the most common and widespread reptilian blood parasites. Haemogregarina stepanowi was the first haemogregarine described from a reptile, the European pond turtle Emys orbicularis, and initial assessments indicated it was widespread across different pond turtle host species across much of Europe, the Middle East and North Africa. However, recent molecular assessments have indicated the presence of multiple genetically distinct forms in North Africa and the Iberian Peninsula, and extensive mixed infections which may be associated with a negative impact on the hosts. Here, we screened two native species, E. orbicularis and Mauremys rivulata, and the introduced Trachemys scripta from Serbia and North Macedonia for haemogregarines by amplifying and sequencing part of the 18S rRNA gene of these parasites, and used a standard DNA barcoding approach to identify leeches, the final host, attached to pond turtles. Our results again demonstrate the occurrence of considerable diversity of parasites in the analysed pond turtle species, and that T. scripta are likely infected by local haemogregarine parasites, and not those that are found in its native range. Leeches were identified as Placobdella costata, part of a lineage from Northern Europe. Mixed infections within pond turtles were again common. Current haemogregarine taxonomy does not reflect the genetic diversity identified, and a full taxonomic reassessment is needed.

Modern studies have shown how parasites add extra complexity to ecosystems through their potential effects on hosts. Blood parasites are common in lizards and various studies have suggested varying degrees of negative effects on these hosts. In this study, we investigate effects of infection by blood parasites on the boldness and aggressiveness of male lizards of two sympatric species living in North Portugal: Podarcis bocagei and Podarcis lusitanicus, known to host blood parasites of two protozoan orders: Adeleorina and Eimeriorina (Apicomplexa). We used a mirror to quantify behavioural interactions of the lizards with their specular images, which did not identify any influence of parasite infection on either species. Boldness was evaluated through exploratory tests, with an identified trend for parasitized P. lusitanicus towards higher exploratory activity and exposure time. This was independent of the intensity of infection. No such effect was found for P. bocagei. The behavioural changes for infected P. lusitanicus appear to be in the direction of increasing light exposure by spending more time directly under the light source, thus suggesting a link with thermoregulation, although further experiments to clarify this hypothesis are required. These results highlight the importance of understanding individual parasite-host relationships, as they show that the same parasites can have different effects across even closely related species. Significance statement: Parasites can affect their host in a variety of ways. We used mirror-interaction and exploratory tests to assess the effects of blood parasites in the aggressiveness and boldness behavioural traits of two sympatric lizard species: Podarcis bocagei and Podarcis lusitanicus. No effect of blood parasite infection in these two behavioural traits was identified on Podarcis bocagei. Podarcis lusitanicus tended to demonstrate a response to infection by Adeleorina with an increase in boldness and willingness to increase exposure times, despite low intensity of infection. Our results show how the same parasites can differently affect closely related host taxa from the same system, and how their effects can be significant even when intensities of infection are low.

Patterns of morphological and genetic diversity within the fringe-toed lizards of the genus Acanthodactylus have puzzled systematists since the first assessments, and none more so than the Acanthodactylus erythrurus complex. A recent study combining multi-locus sequence data and morphological characters partially resolved the situation, identifying two new species in the southern part of the range in Morocco, but leaving an unresolved “Ibero-Moroccan” clade containing much of the genetic and morphological diversity. Here we sequenced a mitochondrial marker for new samples from across much of the distribution. Our data notably increase the known ranges of various species and lineages found in Morocco, and indicate a divergent genetic lineage within one of the newly described species. While far greater numbers of genetic markers will be needed to resolve taxonomic questions, greater geographic sampling is also still needed both to delimit the species, and to identify regions where potential genetic admixture may occur.

Data mining animal of genomes has been used before to identify endoparasites, and may be a particularly useful tool to surpass some difficulties faced by studies in the marine environment. We detected a species of Sarcocystis Lankester, 1882, contamination in the sperm whale (Physeter catodon Linnaeus) reference genome available in the GenBank database. We identified and extracted multiple gene fragments and placed the sequences in a phylogenetic framework. Our results indicate that the sequences of Sarcocystis sp. found in the genome do not correspond to any currently described species, despite a few other similar sequences having been identified in fur seals (Pinnipedia) and another sperm whale. Including data from previous studies, we suggest there is enough evidence to support the occurrence of at least four species of Sarcocystis in marine mammals. We also demonstrate that the term "S. canis-like" has been used for samples not closely related to Sarcocystis canis Dubey et Speer, 1991.

Atlantolacerta andreanskyi (Werner, 1929) is an endemic lizard from the High Atlas Mountains region of Morocco. A previous molecular assessment of this species using mitochondrial and nuclear DNA markers uncovered extensive genetic diversity with seven lineages indicative of a species complex. A morphological assessment of six of these lineages did not establish simple diagnostic features, and proposed these should be considered as a cryptic species, while highlighting the need for greater sampling across the range. In this study, we sampled 8 individuals from 5 previously unsampled localities and carried out genetic analyses to compare these populations to the known variation. Phylogenetic reconstruction based on mitochondrial DNA markers (12S rRNA and ND4) corroborates the previously described lineages and identified a new one. Interestingly, the two samples that account for this newly identified lineage have been collected from distinct localities – M’goun and Toumliline – that form a sister taxon to the population of Jbel Azourki.

Understanding how host-parasite relationships respond to environmental factors across long periods of time is vital to understanding the dynamics of parasitic infections. We studied blood parasite infections in two sympatric species of Podarcis lizards in Northern Portugal between 2011 and 2013 and in 2021, analysing parasite data together with host traits and microclimatic conditions to understand how this relationship was maintained through time. Relationships between host traits and parasite infection remained consistent across years, suggesting changes to infection parameters are more dependent on environmental factors than host adaptation. Warmer and drier conditions were significantly related with higher parasite infection prevalence and drier conditions with intensity, although the magnitude of the latter was dependant on host sex. The climatic trend observed during sampled years was of cooling conditions, congruent with the decrease in parasite infection parameters observed, although the lack of intermediate time points means it is unclear if this is a trend or just an isolated drop in prevalence. We also provide insights into a framework for using data obtained through different methodologies in linear model analyses, by homogenising the varying certainty of observations from different methods.