Trophically-transmitted parasites are regularly exposed to potential new hosts through food web interactions. Successful colonization, or switching, to novel hosts, occur readily when 'donor' and 'target' hosts are phylogenetically related, whereas switching between distantly related hosts is rare and may result from stochastic factors (i.e. rare favourable mutations). This study investigates a host-switching event between a marine acanthocephalan specific to pinnipeds that is apparently able to reproduce in Magellanic penguins Spheniscus magellanicus from Brazil. Detailed analysis of morphological and morphometrical data from acanthocephalans from penguins indicates that they belong to Corynosoma australe Johnston, 1937. Partial fragments of the 28S rRNA and mitochondrial cox1 genes were amplified from isolates from penguins and two pinniped species (i.e. South American sea lion Otaria flavescens and South American fur seal Arctocephalus australis) to confirm this identification. Infection parameters clearly differ between penguins and the two pinniped species, which were significantly lower in S. magellanicus. The sex ratio of C. australe also differed between penguins and pinnipeds; in S. magellanicus was strongly biased against males, while in pinnipeds it was close to 1:1. Females of C. australe from O. flavescens were smaller than those from S. magellanicus and A. australis. However, fecundity (i.e. the proportion of fully developed eggs) was lower and more variable in females collected from S. magellanicus. At first glance, the occurrence of reproductive individuals of C. australe in Magellanic penguins could be interpreted as an adaptive colonization of a novel avian host through favourable mutations. However, it could also be considered, perhaps more likely, as an example of ecological fitting through the use of a plesimorphic (host) resource, since the ancestors of Corynosoma infected aquatic birds.

• MeSH
• Acanthocephala * MeSH
• ekologie MeSH
• fylogeneze MeSH
• interakce hostitele a parazita fyziologie   MeSH
• lachtani rodu Arctocephalus a Callorhinus parazitologie   MeSH
• lachtani parazitologie   MeSH
• poměr pohlaví MeSH
• Spheniscidae parazitologie   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

The genus Rhynchocalamus comprises three species distributed in Southwest Asia. Little is known about them, most probably because of their secretive fossorial lifestyle. The poor knowledge of the genus is even underscored by the fact that its phylogenetic affinities remained unclear until very recently. The least known of the species, Rhynchocalamus arabicus, is known only from the holotype collected in Aden, Yemen, and it has not been observed since its description in 1933. Here we provide a second record for this species, which represents the first record of this genus for Oman. This extends its range in southern Arabia by more than 1000 km. The observed specimen was determined as R. arabicus on the basis of its similarity in size, color, and scalation with the holotype. Furthermore, we sequenced three mitochondrial (12S, 16S, cytb) and one nuclear (cmos) genes for R. arabicus and for two individuals of R. melanocephalus and one R. satunini and inferred the phylogenetic relationships of all currently recognized species of the genus for the first time. The results of our phylogenetic analyses indicate that Rhynchocalamus is a member of the Western Palearctic clade of Colubrinae and is sister to Lytorhynchus, with which it forms a very well supported clade and shares some morphological characters. As our results show, R. satunini is the basal lineage of the genus and R. melanocephalus is sister to R. arabicus.

• MeSH
• anatomické struktury zvířat anatomie a histologie   růst a vývoj   MeSH
• Colubridae anatomie a histologie   klasifikace   genetika   růst a vývoj   MeSH
• fylogeneze * MeSH
• RNA ribozomální 16S genetika   MeSH
• rozšíření zvířat MeSH
• velikost orgánu MeSH
• velikost těla MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Omán MeSH

In the present work, we use an exceptional database including 5,359 records of 101 species of Oman's terrestrial reptiles together with spatial tools to infer the spatial patterns of species richness and endemicity, to infer the habitat preference of each species and to better define conservation priorities, with especial focus on the effectiveness of the protected areas in preserving this unique arid fauna. Our results indicate that the sampling effort is not only remarkable from a taxonomic point of view, with multiple observations for most species, but also for the spatial coverage achieved. The observations are distributed almost continuously across the two-dimensional climatic space of Oman defined by the mean annual temperature and the total annual precipitation and across the Principal Component Analysis (PCA) of the multivariate climatic space and are well represented within 17 out of the 20 climatic clusters grouping 10% of the explained climatic variance defined by PC1 and PC2. Species richness is highest in the Hajar and Dhofar Mountains, two of the most biodiverse areas of the Arabian Peninsula, and endemic species richness is greatest in the Jebel Akhdar, the highest part of the Hajar Mountains. Oman's 22 protected areas cover only 3.91% of the country, including within their limits 63.37% of terrestrial reptiles and 50% of all endemics. Our analyses show that large areas of the climatic space of Oman lie outside protected areas and that seven of the 20 climatic clusters are not protected at all. The results of the gap analysis indicate that most of the species are below the conservation target of 17% or even the less restrictive 12% of their total area within a protected area in order to be considered adequately protected. Therefore, an evaluation of the coverage of the current network of protected areas and the identification of priority protected areas for reptiles using reserve design algorithms are urgently needed. Our study also shows that more than half of the species are still pending of a definitive evaluation by the International Union for Conservation of Nature (IUCN).

• MeSH
• biodiverzita * MeSH
• ekosystém MeSH
• plazi klasifikace   MeSH
• podnebí MeSH
• zachování přírodních zdrojů metody   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Omán MeSH