The white grunt, Haemulon plumierii (Lacepède, 1801) as paratenic and definitive host of two acanthocephalan species, with the description of a new species of Dollfusentis (Palaeacanthocephala: Leptohynchoididae) from the Yucatán Peninsula, Mexico.

Acanthocephalans are a group of obligate endoparasites that alternate between vertebrates and invertebrates to complete their life cycles. Occasionally, the same individual host acts as a definitive or paratenic host for different acanthocephalan species. In this study, acanthocephalans were sampled in marine fish in three localities of the Yucatán Peninsula; adults and cystacanths were recovered from the intestine and body cavity, respectively, of Haemulon plumierii from off the coast of Sisal, Yucatán. Ribosomal DNA sequences (small and large subunits) were used to test the phylogenetic position of the species of the genus Dollfusentis, whereas the mtDNA gene cox 1 was used for assessing species delimitation. The cox 1 analysis revealed an independent genetic lineage, which is recognized herein as a new species, Dollfusentis mayae n. sp. The new species is morphologically distinguished from the other six congeners by having a cylindrical proboscis armed with 22-25 longitudinal rows bearing 12 hooks each. The cystacanths were morphologically identified as Gorgorhynchus medius by having a cylindrical trunk covered with tiny irregular spines on the anterior region, and a cylindrical proboscis armed with 17-18 longitudinal rows of 21 hooks each; small and large subunit phylogenetic analyses yielded G. medius within the family Isthomosacanthidae, suggesting that Gorgorhynchus should be transferred to this family from Rhadinorhynchidae where it is currently allocated.

The complete mitochondrial genome of 3 species of allocreadiids (Digenea, Allocreadiidae): characterization and phylogenetic position within the order Plagiorchiida.

Trematodes of the family Allocreadiidae are primarily found in the intestines of freshwater fishes around the world. The family includes 15 genera and c. 130 species. The last 2 decades have witnessed an increase in the genetic library of its species. Molecular data have been crucial for species delimitation and species description within Allocreadiidae and for understanding their evolutionary and biogeographical history and classification. Here, the mitogenomes of 3 species of allocreadiids were obtained using high throughput sequencing methods. Mitogenomes were compared with other members of the order Plagiorchiida to determine their molecular composition, gene rearrangement and phylogenetic interrelationships. The complete circular mitogenomes of Allocreadium lobatum, Creptotrematina aguirrepequenoi and Wallinia mexicana were 14 424, 13 769 and 13 924 bp long respectively, comprising 12 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes and 2 non-coding regions. Gene arrangements were identical to other Xiphidiatan trematodes. Phylogenetic analyses using the mitogenomes revealed Allocreadiidae as a monophyletic group closely related to other members of the suborder Xiphidiata; A. lobatum was yielded as the sister taxon of C. aguirrepequenoi + W. mexicana. Our study increases the complete mitochondrial genome library of trematodes and strengthens our understanding of the phylogenetic relationships and classification of this parasite group.

Molecular species delimitation of marine trematodes over wide geographical ranges: Schikhobalotrema spp. (Digenea: Haplosplanchnidae) in needlefishes (Belonidae) from the Pacific Ocean and Gulf of Mexico.

Geographical distribution plays a major role in our understanding of marine biodiversity. Some marine fish trematodes have been shown to have highly restricted geographical distributions, while some are known to occur over very wide ranges; however, very few of these wide distributions have been demonstrated genetically. Here, we analyse species of the genus Schikhobalotrema (Haplosplanchnidae) parasitizing beloniforms from the tropical west Pacific, the eastern Pacific and the Gulf of Mexico (GoM). We test the boundaries of these trematodes by integrating molecular and morphological data, host association, habitat of the hosts and geographical distribution, following a recently proposed and standardized delineation method for the recognition of marine trematode species. Based on the new collections, Schikhobalotrema huffmani is here synonymized with the type-species of the genus, Schikhobalotrema acutum; Sch. acutum is now considered to be widely distributed, from the GoM to the western Pacific. Additionally, we describe a new species, Schikhobalotrema minutum n. sp., from Strongylura notata and Strongylura marina (Belonidae) from La Carbonera coastal lagoon, northern Yucatán, GoM. We briefly discuss the role of host association and historical biogeography of the hosts as drivers of species diversification of Schikhobalotrema infecting beloniforms.

Molecular data aids pinworm diagnosis in night monkeys (Aotus spp., Primates: Aotidae) with the resurrection of a Trypanoxyuris species (Nematoda: Oxyuridae).

Neotropical primates (Platyrrhines) are commonly parasitized by pinworm nematodes of the genus Trypanoxyuris Vevers, 1923. The taxonomic identity of Trypanoxyuris sampled in night monkeys (Aotus Iliger) has been rather controversial. Two species have been described, namely T. microon (Linstow, 1907) and T. interlabiata (Sandosham, 1950). The latter was synonymized with T. microon considering that the observed morphological differences corresponded to different developmental stages of the nematode rather than to differences between both species. Here, we used an integrative taxonomy approach, based on morphological and molecular data along with host identity, in order to assess the validity of both species. Our results evidenced that these different morphotypes correspond to different and reciprocally monophyletic groups; thus, we propose the resurrection of T. interlabiata. We redescribe both pinworm species using specimens sampled in Aotus monkeys from Colombia and discuss the advantages of combining molecular and morphological data to uncover pinworm diversity, and to understand the potential forces determining the diversification process in pinworms from platyrrhine primates.

Monorchiids (Digenea, Trematoda) of fishes in the Yucatán Peninsula, Mexico, with the description of three new species based on morphological and molecular data.

Adult specimens of monorchiids (Digenea) were collected from the intestines of the white grunt, Haemulon plumierii Lacepède (Haemulidae), and the white mullet, Mugil curema Valenciennes (Mugilidae) from five localities off the Yucatán Peninsula and one locality in the Gulf of Mexico. Some specimens were photographed and sequenced for two molecular markers, the large subunit (LSU) of nuclear rDNA and the cytochrome c oxidase subunit 1 (cox1) of mitochondrial DNA. Other specimens were processed for morphological analyses. Newly generated sequences were aligned with other sequences available in GenBank. Bayesian inference and maximum likelihood analyses were implemented using the data sets of LSU and cox1 independently. Reciprocal monophyly evidenced through phylogenetic analyses, sequence divergence values for both molecular markers, and detailed morphological analyses, including scanning electron microscopy photomicrographs, revealed three new genetic lineages, i.e., species, as parasites of M. curema. The three new species are Sinistroporomonorchis mexicanus n. sp., Sinistroporomonorchis yucatanensis n. sp., and Sinistroporomonorchis minutus n. sp. Two additional species of monorchiids were sampled, characterised molecularly, and re-described, namely Sinistroporomonorchis glebulentus (Overstreet, 1971) from the white mullet, and Alloinfundiburictus haemuli (Overstreet, 1969), from the white grunt.

Title: Monorchiidae (Digenea, Trematoda) de poissons de la péninsule du Yucatán, Mexique, avec description de trois nouvelles espèces sur la base de données morphologiques et moléculaires. Abstract: Des spécimens adultes de Monorchiidae (Digenea) ont été collectés dans les intestins de la gorette blanche, Haemulon plumierii Lacepède (Haemulidae), et du mulet blanc, Mugil curema Valenciennes (Mugilidae) de cinq localités au large de la péninsule du Yucatán et d'une localité dans le Golfe du Mexique. Certains spécimens ont été photographiés et séquencés pour deux marqueurs moléculaires, la grande sous-unité (LSU) de l'ADNr nucléaire et la sous-unité 1 de la cytochrome c oxydase (cox1) de l'ADN mitochondrial. D'autres spécimens ont été traités pour des analyses morphologiques. Les séquences nouvellement générées ont été alignées avec d'autres séquences disponibles dans GenBank. L'inférence bayésienne et les analyses de vraisemblance maximale ont été mises en œuvre en utilisant les ensembles de données de LSU et cox1 indépendamment. La monophylie réciproque mise en évidence par des analyses phylogénétiques, des valeurs de divergence de séquence pour les deux marqueurs moléculaires et des analyses morphologiques détaillées, y compris des photomicrographies au microscope électronique à balayage, a révélé trois nouvelles lignées génétiques, c'est-à-dire des espèces, qui sont parasites de M. curema. Les trois nouvelles espèces sont Sinistroporomonorchis mexicanus n. sp., Sinistroporomonorchis yucatanensis n. sp. et Sinistroporomonorchis minutus n. sp. (Monorchiidae). Deux espèces supplémentaires de Monorchiidae ont été échantillonnées, caractérisées moléculairement et redécrites, à savoir Sinistroporomonorchis glebulentus (Overstreet, 1971) du mulet blanc et Alloinfundiburictus haemuli (Overstreet, 1969) de la gorette blanche.

Parasitism in heterogeneous landscapes: Association between conserved habitats and gastrointestinal parasites in populations of wild mammals.

Parasites constitute essential elements of biodiversity, playing fundamental roles for the functioning and configuration of any ecosystem. The continuous and accelerated human expansion into previously pristine territories is changing landscape structure and climatic regimes that could alter host - parasite dynamics. We explore the influence of landscape structure and habitat quality on gastrointestinal parasites in several species of mammals inhabiting remnants of tall evergreen forest within a matrix of anthropic vegetation. Here, we record 32 taxa of gastrointestinal parasites with nematodes as the most diverse group. Landscape variables such as forest edge density, river density and percentage of conserved habitat were among the best predictors of gastrointestinal parasites. Parasite species richness increased with a higher proportion of conserved habitat, but hosts living in disturbed areas show higher intensity of infection. The results presented here indicate that parasites are susceptible to habitat perturbation. It is pertinent to keep monitoring wildlife health in human dominated landscapes to understand disease dynamics, zoonotic risk, and ecosystem health.

Co-structure analysis and genetic associations reveal insights into pinworms (Trypanoxyuris) and primates (Alouatta palliata) microevolutionary dynamics.

BACKGROUND: In parasitism arm race processes and red queen dynamics between host and parasites reciprocally mold many aspects of their genetics and evolution. We performed a parallel assessment of population genetics and demography of two species of pinworms with different degrees of host specificity (Trypanoxyuris multilabiatus, species-specific; and T. minutus, genus-specific) and their host, the mantled howler monkey (Alouatta palliata), based on mitochondrial DNA sequences and microsatellite loci (these only for the host). Given that pinworms and primates have a close co-evolutionary history, covariation in several genetic aspects of their populations is expected. RESULTS: Mitochondrial DNA revealed two genetic clusters (West and East) in both pinworm species and howler monkeys, although population structure and genetic differentiation were stronger in the host, while genetic diversity was higher in pinworms than howler populations. Co-divergence tests showed no congruence between host and parasite phylogenies; nonetheless, a significant correlation was found between both pinworms and A. palliata genetic pairwise distances suggesting that the parasites' gene flow is mediated by the host dispersal. Moreover, the parasite most infective and the host most susceptible haplotypes were also the most frequent, whereas the less divergent haplotypes tended to be either more infective (for pinworms) or more susceptible (for howlers). Finally, a positive correlation was found between pairwise p-distance of host haplotypes and that of their associated pinworm haplotypes. CONCLUSION: The genetic configuration of pinworm populations appears to be molded by their own demography and life history traits in conjunction with the biology and evolutionary history of their hosts, including host genetic variation, social interactions, dispersal and biogeography. Similarity in patterns of genetic structure, differentiation and diversity is higher between howler monkeys and T. multilabiatus in comparison with T. minutus, highlighting the role of host-specificity in coevolving processes. Trypanoxyuris minutus exhibits genetic specificity towards the most frequent host haplotype as well as geographic specificity. Results suggest signals of potential local adaptation in pinworms and further support the notion of correlated evolution between pinworms and their primate hosts.

Exploring the genetic structure of Parastrigea diovadena Dubois and Macko, 1972 (Digenea: Strigeidae), an endoparasite of the white ibis, Eudocimus albus, from the Neotropical region of Mexico.

Parastrigea diovadena Dubois and Macko, 1972, is an allogenic trematode species that infects the intestine of white ibis. This widely distributed Neotropical species has been studied poorly, and nothing is known about its population genetic structure. In the current study, we attempt to fill this gap for the first time and to explore the genetic diversity in P. diovadena populations from three biogeographic provinces (Sierra Madre Oriental, Sierra Madre Occidental, and Sierra Madre del Sur) in the Neotropical region of Mexico. Newly generated sequences of the internal transcribed spacers (ITS) from ribosomal DNA and cytochrome c oxidase subunit 1 (cox 1) from mitochondrial DNA were compared with sequences available from the GenBank data set. Phylogenetic analyses performed with the ITS and cox 1 data sets using maximum likelihood and Bayesian inference unequivocally showed that new sequences of P. diovadena recovered from the white ibis formed a clade with other sequences of specimens previously identified as P. diovadena. The intraspecific genetic divergence among the isolates was very low, ranging from 0 to 0.38% for ITS and from 0 to 1.5% for cox 1, and in combination with the phylogenetic trees confirmed that the isolates belonged to the same species. The cox 1 haplotype network (star-shaped) inferred with 62 sequences revealed 36 haplotypes. The most frequent haplotype (H3, n = 18) corresponded to specimens from all the populations (except Tecolutla, Veracruz). In addition to the common haplotype, we identified four other shared haplotypes (H2, H9, H12, and H14) and 31 unique haplotypes (singlets). In addition, high haplotype diversity (Hd = 0.913), low nucleotide diversity (Pi = 0.0057), and null genetic differentiation or population structure (Fst = 0.0167) were found among the populations from the three biogeographic provinces. The results suggest that the biology of the definitive host has played a key role in the population genetic structure of Parastrigea diovadena in the Neotropical region of Mexico.

Batracholandros salamandrae (Oxyuroidea: Pharyngodonidae) in Endemic Salamanders (Amphibia: Plethodontidae) of the Trans-Mexican Volcanic Belt: Host Range Wide Distribution or Cryptic Species Complex?

Salamanders of the tribe Bolitoglossini Hallowell are a highly diversified group of amphibians, and their helminth parasite fauna has been scarcely studied. Some species of plethodontid salamanders distributed along the Trans-Mexican Volcanic Belt, in central Mexico, were sampled, and their helminth parasites were recovered for taxonomic identification. Specimens of a pharyngodonid nematode from 2 species of bolitoglossines of the genus Pseudoeurycea Taylor were morphologically identified as Batracholandros salamandrae (Schad, 1960) Petter and Quentin, 1976. These specimens were studied in further detail through light and scanning electron microscopy and were sequenced for 2 ribosomal genes and 1 mitochondrial gene to test the hypothesis of whether B. salamandrae is a species widely distributed in salamanders across the Nearctic biogeographic region, or if it represents a cryptic species complex. Our molecular results revealed that these specimens consisted of 2 genetic lineages in concordance with host species, although with slight morphological differences among specimens in each of them. A thorough study, including the generation of molecular data from individuals from other areas of North America, and the examination of type specimens, is required to test the reliability of these morphological differences and to corroborate the species identity of the 2 genetic lineages.

Pinworms of the red howler monkey (Alouatta seniculus) in Colombia: Gathering the pieces of the pinworm-primate puzzle.

Pinworms of primates are believed to be highly host specific parasites, forming co-evolutionary associations with their hosts. In order to assess the strength and reach of such evolutionary links, we need to have a broad understanding of the pinworm diversity associated with primates. Here, we employed an integrative taxonomic approach to assess pinworm diversity in red howler monkeys in Colombia. Molecular and morphological evidence validate the presence of at least four different species of Trypanoxyuris occurring in red howler monkeys: T. minutus, a widely distributed species, and three new species, T. seunimiii n. sp., T. kemuimae n. sp. and T. kotudoi n. sp. The mitochondrial COI gene and the 28S ribosomal gene were used for phylogenetic assessments through Bayesian inference. The three new species were morphologically distinct and formed reciprocally monophyletic lineages. Further molecular lineage subdivision in T. minutus and T. kotudoi n. sp. without morphological correspondence, suggests the potential scenario for the existence of cryptic species. Phylogenetic relationships imply that the different species of Trypanoxyuris occurring in each howler monkey species were acquired through independent colonization events. On-going efforts to uncover pinworm diversity will allow us to test the degree of host specificity and the co-phylogenetic hypothesis, as well as to further unravel the primate-pinworm evolutionary history puzzle.

Unveiling patterns of genetic variation in parasite-host associations: an example with pinworms and Neotropical primates.

Patterns of genetic variation among populations can reveal the evolutionary history of species. Pinworm parasites are highly host specific and form strong co-evolutionary associations with their primate hosts. Here, we describe the genetic variation observed in four Trypanoxyuris species infecting different howler and spider monkey subspecies in Central America to determine if historical dispersal processes and speciation in the host could explain the genetic patterns observed in the parasites. Mitochondrial (cox1) and ribosomal (28S) DNA were analysed to assess genetic divergence and phylogenetic history of these parasites. Sequences of the 28S gene were identical within pinworms species regardless of host subspecies. However, phylogenetic analyses, haplotype relationships and genetic divergence with cox1 showed differentiation between pinworm populations according to host subspecies in three of the four Trypanoxyuris species analysed. Haplotype separation between host subspecies was not observed in Trypanoxyuris minutus, nor in Trypanoxyuris atelis from Ateles geoffoyi vellerosus and Ateles geoffoyi yucatanensis. Levels of genetic diversity and divergence in these parasites relate with such estimates reported for their hosts. This study shows how genetic patterns uncovered in parasitic organisms can reflect the host phylogenetic and biogeographic histories.

Lack of genetic structure in pinworm populations from New World primates in forest fragments.

Microevolutionary processes in parasites are driven by factors related to parasite biology, host abundance and dispersal, and environmental conditions. Here, we test the prediction that isolation of host populations results in reduced genetic diversity and high differentiation among parasite populations. We conducted a population genetic analysis of two pinworms, Trypanoxyuris minutus and Trypanoxyuris atelis, commonly found parasitizing howler and spider monkeys in tropical rainforests across south-eastern Mexico, whose populations are currently isolated due to anthropogenic habitat loss and fragmentation. Mitochondrial DNA was employed to assess parasite genetic patterns, as well as to analyse their demography and population history. Both pinworm species showed high haplotype diversity but, unexpectedly, lower nucleotide diversity than that reported for other parasites. No genetic differentiation or population structure was detected in either pinworm species despite habitat loss, fragmentation and host isolation. Several scenarios are discussed that could help to explain the genetic panmixia found in both pinworm species, including higher than expected primate inter-fragment dispersal movements, and passive dispersal facilitating gene flow between parasite populations. The results suggest that large population sizes of parasites could be helping them to cope with the isolation and fragmentation of populations, delaying the effects of genetic drift. The present study highlights the complexity of the drivers that intervene in the evolutionary processes of parasites. Detailed genetic studies are needed, both in host and parasite populations, to assess the effects that habitat perturbation and environmental changes could have on the evolutionary dynamics of pinworms and primates.

Helminth parasites of howler and spider monkeys in Mexico: Insights into molecular diagnostic methods and their importance for zoonotic diseases and host conservation.

The majority of the parasite assessments of New World primates have been conducted through the identification of the eggs found in faeces, though many species of parasites have very similar eggs, leaving uncertainty in the diagnosis. Here, we present the results of a parasite survey of the three species of primates distributed in Mexico, combining non-invasive sampling with molecular techniques via DNA extraction of the eggs found in the faeces. Mitochondrial and ribosomal DNA were employed for species identification and Bayesian phylogenetic analysis. Nine parasite taxa were found in the three primate species: the nematodes Trypanoxyuris minutus, T. multilabiatus, T. pigrae, T. atelis, T. atelophora, Strongyloides sp., unidentified Ancylostomatid, unidentified Ascarid, and the trematode Controrchis biliophilus. We were able to extract and amplify DNA from the eggs of the five species of Trypanoxyuris reported for Mexican primates, two morphologically different trematode eggs, and Strongyloides sp. Phylogenetic analysis confirmed that the two types of trematode eggs belong to Controrchis biliophilus, a member of the family Dicrocoeliidae. For Strongyloides sp., phylogenetic analysis and genetic divergence showed an association between our samples and S. fuelleborni; however, no species could be established due to the lack of more DNA sequences from Strongyloides sp. occurring in Neotropical primates. The use of molecular and phylogenetic methods could help to overcome the limitations imposed by traditional non-invasive sampling because eggs are primarily obtained from the faeces; however, its utility relies on the extant genetic library and the contributions that expand such library. The information presented here could serve as a basis for future research on primate parasitology, allowing a more accurate parasite diagnosis and a more precise evaluation of their zoonotic potential.

Pinworm diversity in free-ranging howler monkeys (Alouatta spp.) in Mexico: Morphological and molecular evidence for two new Trypanoxyuris species (Nematoda: Oxyuridae).

Two new species of Trypanoxyuris are described from the intestine of free-ranging howler monkeys in Mexico, Trypanoxyuris multilabiatus n. sp. from the mantled howler Alouatta palliata, and Trypanoxyuris pigrae n. sp. from the black howler Alouatta pigra. An integrative taxonomic approach is followed, where conspicuous morphological traits and phylogenetic trees based on DNA sequences are used to test the validity of the two new species. The mitochondrial cytochrome oxidase subunit 1 gene, and the nuclear ribosomal 18S and 28S rRNA genes were used for evolutionary analyses, with the concatenated dataset of all three genes used for maximum likelihood and Bayesian phylogenetic analyses. The two new species of pinworms from howler monkeys were morphologically distinct and formed reciprocally monophyletic lineages in molecular phylogenetic trees. The three species from howler monkeys, T. multilabiatus n. sp., T. pigrae n. sp., and Trypanoxyuris minutus, formed a monophyletic group with high bootstrap and posterior probability support values. Phylogenetic patterns inferred from sequence data support the hypothesis of a close evolutionary association between these primate hosts and their pinworm parasites. The results suggest that the diversity of pinworm parasites from Neotropical primates might be underestimated.

Trypanoxyuris atelis and T. atelophora (Nematoda: Oxyuridae) in wild spider monkeys (Ateles geoffroyi) in tropical rain forest in Mexico: Morphological and molecular evidence.

Two species of pinworms, Trypanoxyuris atelis and Trypanoxyuris atelophora were collected from the black-handed spider monkey (Ateles geoffroyi) in several localities across southeastern Mexico, representing the first record for both species in Mexican primates. Identification of pinworm species was based on morphological and molecular data. These pinworms are distinguished from other congeners, and from each other, by the buccal structure, the lateral alae, and the morphology of the oesophagus. Phylogenetic analyses based on sequences of the mitochondrial cytochrome c oxidase subunit 1 gene placed T. atelis as the sister species of Trypanoxyuris minutus, a parasite of the howler monkey Alouatta palliata, and T. atelophora as the sister species of T. microon, a parasite of the night monkey, Aotus azarae. These relationships were supported with high posterior probability values by Bayesian inference. Comparisons of additional pinworm taxa from Neotropical primates are needed to assess oxyurid diversity, and to better understand the evolutionary relationships among these nematodes and their primate hosts.