We compared lizard endoparasite assemblages between the Atlantic Forest and naturally isolated forest enclaves to test the ecological release hypothesis, which predicts that host specificity should be lower (large niche breadth) and parasite abundance should be greater for parasites from isolated forest enclaves (poor assemblages) than for parasites from the coastal Atlantic Forest (rich assemblages). Parasite richness per specimen showed no difference between the isolated and non-isolated areas. Parasite abundance did not differ between the isolated and non-isolated areas but showed a positive relationship with parasite richness considering all areas (isolated and non-isolated). Furthermore, host specificity was positively related to parasite richness. Considering that host specificity is inversely proportional to the host range infected by a parasite, our results indicate that in assemblages with greater parasite richness, parasites tend to infect a smaller range of hosts than do those in simple assemblages. In summary, our study partially supports the ecological release hypothesis: in assemblages with greater parasite richness, lizard parasites from Atlantic Forest are able to increase their parasite abundance (per host), possibly through facilitated infection; however, the amplitude of infected hosts only expands in poor assemblages (lower parasite richness).

Helminths and pentastomids were examined in exotic Hemidactylus mabouia and native Phyllopezus pollicaris lizards, living synanthropically in an urban area in the municipality of Crato, Ceará state, northeastern Brazil. A total of 194 lizards were collected, being 76 specimens of H. mabouia e 118 specimens of P. pollicaris. Six parasite species were found infecting H. mabouia: the cestode Oochoristica sp., the nematodes Parapharyngodon sceleratus, Physaloptera retusa, Physalopteroides venancioi, and Spauligodon oxkutzcabiensis and the pentastomid Raillietiella mottae; while four parasite species were found associated with P. pollicaris: Oochoristica sp., P. sceleratus, P. retusa, and S. oxkutzcabiensis. Three new host records were reported: P. retusa infecting H. mabouia and P. retusa and Oochoristica sp. infecting P. pollicaris. About 75% of the parasites species found were shared by both lizards. Moreover, H. mabouia showed greater diversity than P. pollicaris (6 versus 4 species), while P. pollicaris had higher intensity of infection than H. mabouia (1536 versus 121 specimens).

Abstract:We investigated the parasites of five lizard species belonging to Phyllodactylidae (Phyllopezus pollicaris and Gymnodactylus geckoides) and Gekkonidae (Hemidactylus agrius, Lygodactylus klugei and Hemidactylus brasilianus) families in a semiarid region of Brazil. Six nematode species were identified: Parapharyngodon alvarengai and Spauligodon oxkutzcabiensis (Pharyngodonidae), Physaloptera lutzi (Physalopteridae), Skrjabinelazia intermedia (Seuratidae), Trichospirura sp. (Rhabdochonidae) and Piratuba sp. (Onchocercidae), and a cestode species, Oochoristica sp. (Linstowiidae). The most prevalent species were Spauligodon oxkutzcabiensis, which infected P. pollicaris (75%), and Parapharyngodon alvarengai, which infected G. geckoides (29%). South American lizards were identified as being new hosts for the Trichospirura genus (a usual parasite of mammals), and there were 16 new occurrences of parasite species in the five lizard species studied herein. Keywords

The distribution of parasites within host populations and communities, and the mechanisms responsible for these patterns, are poorly understood aspects of wildlife parasitology. Here, we evaluate the influence of the average abundance of endoparasite variance, using endoparasites of lizards from the Caatinga domain (semiarid region), north-eastern Brazil. We hypothesized that, due to the high number of generalist endoparasite species, they may occur randomly throughout host populations in an aggregate pattern. In addition, we evaluated the degree to which sample variance is influenced by the average abundance of endoparasite species, patterns of co-occurrence and dominance among endoparasite species and similarities between abundance and the richness of endoparasite infracommunities in several host species. Between September 2015 and February 2016, 2141 lizards (1233 infected) from 16 species were collected from six Caatinga areas. In total, 25,687 endoparasites were collected, which belonged to 13 species including nematodes, pentastomids, cestodes, trematodes and acanthocephalans. Parasite–host associations documented here included 39 newly identified interactions. Endoparasites occurred in a typical aggregate pattern of distribution within their hosts; there was no measurable preference related to the acquisition of hosts by endoparasites. Despite the new records, endoparasites found were commonly associated with lizards in Caatinga environments, which may reflect fauna composed of generalist endoparasite species.

The lizard Salvator merianae is a widely distributed species in South America, occurring from southern Amazonia to the eastern Andes and northern Patagonia. Studies on the parasitic fauna of this lizard have revealed that it is a host for helminths in various Brazilian biomes. The present work provides new parasitological data on the gastrointestinal nematodes associated with the lizard S. merianae. Sixteen specimens were analyzed from nine different locations in a semi-arid region in northeastern Brazil. Five species of nematodes were identified. Oswaldofilaria petersi was first recorded as a parasite of the S. merianae, thus increasing the knowledge of the fauna of parasites that infect large Neotropical lizards.Keywords: parasitism, nematode, Oswaldofilaria petersi, Brazilian semiarid. Helmintos do lagarto

Nematodes were analyzed in Iguana iguana, a large lizard Iguanidae that is widely distributed throughout the Americas. The aims of the study were investigate the helminths associated with the lizard, I. iguana in semi-arid areas of northeastern Brazil and analyze the parasitological indices (prevalence, and mean intensity of infection). A total of 18 specimens of I. iguana were examined (8 males and 10 females). The overall prevalence of infection was 66.6% (12/18), while in males, it was 75% (6/8) and in females, 60% (6/10). Iguana iguana was identified as a new host for Physaloptera sp., Atractis sp., Piratuba sp. and Subulura sp. This registered contributes to the knowledge of helminth diversity associated with this host.Keywords: helminths, Green Iguana, parasitism, Caatinga domain. Nematoda associados a Iguana iguana (Linnaeus, 1758) (Squamata: Iguanidae) em áreas do semi-árido do nordeste do Brasil ResumoForam analisados os nematóides em Iguana iguana, um grande lagarto Iguanidae que possui ampla distribuição pelas Américas. Os objetivos do estudo foram investigar os helmintos associados ao lagarto I. iguana e seus índices parasitológicos (prevalência e intensidade média de infecção). Foram examinados 18 espécimes (oito machos e 10 fêmeas). A prevalência total foi de 66,6% (12/18), nos machos foi de 75% (6/8) e nas fêmeas 60% (6/10). Iguana iguana foi identificado como um novo hospedeiro para Physaloptera sp., Atractis sp., Piratuba sp., e Subulura sp. Este registro contribui para o conhecimento da diversidade de helmintos associados a este hospedeiro.Palavras-chave: helmintos, Iguana Verde, parasitismo, domínio de Caatinga.

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