Juan J. Morrone y Jorge Llorente Busquets (eds). 2003. Una perspectiva latinoamericana de la biogeografía. Las prensas de ciencias. Universidad Nacional Autónoma de México. México, D.F. 307pp

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A New Species of \u3ci\u3eAcanthobothrium\u3c/i\u3e Van Beneden, 1849 (Eucestoda: Tetraphyllidea: Onchobothriidae) in \u3ci\u3eDasyatis longus\u3c/i\u3e Garman (Chondrichthyes: Myliobatiformes: Dasyatididae) from Chamela Bay, Jalisco, Mexico

A new species of Acanthobothrium in Dasyatis longus from Chamela Bay, Jalisco, Mexico, is a member of a presumed clade of species diagnosed by being anapolytic or nearly so, having more than 100 testes per proglottis, with immature and mature proglottides wider than long to square, aspinose scolex, muscular bothridia fused to the scolex at their posterior ends, H- to V-shaped ovaries, relatively short symmetrical to asymmetrical ovarian arms that extend anteriorly to, or nearly to, the cirrus sac, and vitellaria arranged in fields rather than a single row of follicles. The new species most closely resembles Acanthobothrium terezae from the freshwater stingray Potamotrygon motoro in the following characters: bothridial hooks longer than 200 μm with inner hooks having bent asymmetrical prongs, an average of 130-140 testes per proglottis, and shallow genital atria located posterior to midline of proglottis. The new species differs from A. terezae by having outer hooks approximately the same size and shape as the inner hooks, inner hooks averaging 230 μm rather than 313 μm in total length, and cirrus sacs averaging 255 μm rather than 450 μm in length. The new species is unique among all described species of Acanthobothrium by having a cleft in the posterior margin of each apical bothridial pad. The apparent close relationship of the new species to one inhabiting a Neotropical freshwater stingray provides support for the hypothesized Pacific marine ancestry of Neotropical freshwater stingrays and raises the possibility that the Neotropical freshwater stingrays may not be monophyletic

Phylogenetic relationships and biogeography of the genus Algansea Girard (Cypriniformes: Cyprinidae) of central Mexico inferred from molecular data

42 pages, 2 additional files, 6 figures, 1 table.[Background] The genus Algansea is one of the most representative freshwater fish groups in central Mexico due to its wide geographic distribution and unusual level of endemicity. Despite the small number of species, this genus has had an unsettled taxonomic history due to high levels of intraspecific morphological variation. Moreover, several phylogenetic hypotheses among congeners have been proposed but have had the following shortcomings: the use of homoplasious morphological characters, the use of character codification and polarisation methods that lacked objectivity, and incomplete taxonomic sampling. In this study, a phylogenetic analysis among species of Algansea is presented. This analysis is based upon two molecular markers, the mitochondrial gene cytochrome b and the first intron of the ribosomal protein S7 gene.[Results] Bayesian analysis based on a combined matrix (cytochrome b and first intron S7) showed that Algansea is a monophyletic group and that Agosia chrysogaster is the sister group. Divergence times dated the origin of the genus around 16.6 MYA, with subsequent cladogenetic events occurring between 6.4 and 2.8 MYA. When mapped onto the molecular phylogenetic hypothesis, the character states of three morphological characters did not support previous hypotheses on the evolution of morphological traits in the genus Algansea, whereas the character states of the remaining six characters partially corroborated those hypotheses.[Conclusions] Monophyly of the genus Algansea was corroborated in this study. Tree topology shows the genus consists of three main lineages: Central-Eastern, Western, and Southern clades. However, the relationships among these clades remained unresolved. Congruence found between the available geological and climatic history and the divergence times made it possible to infer the biogeographical history of Algansea, which suggested that vicariance events were responsible for the evolutionary history of the genus. Interestingly, this pattern was shared with other members of the freshwater fish fauna of central Mexico. In addition, molecular data also show that some morphological traits alleged to represent synapomorphies in previous studies were actually homoplasies. Others traits were corroborated as synapomorphies, particularly in those species of a subgroup corresponding with the Central-Eastern clade within Algansea; this corroboration is interpreted as a result of evolutionary adaptations.This study was partially funded by grants from CGL2006-12325/BOS, the program PAPIIT-UNAM-IN209608, and CONACYT (grant number 83043) to GPPDL. RPR thank the Consejo Nacional de Ciencia y Tecnología for the scholarship.Peer reviewe

Evolutionary history of the endangered fish Zoogoneticus quitzeoensis (Bean, 1898) (Cyprinodontiformes: Goodeidae) using a sequential approach to phylogeography based on mitochondrial and nuclear DNA data

<p>Abstract</p> <p>Background</p> <p>Tectonic, volcanic and climatic events that produce changes in hydrographic systems are the main causes of diversification and speciation of freshwater fishes. Elucidate the evolutionary history of freshwater fishes permits to infer theories on the biotic and geological evolution of a region, which can further be applied to understand processes of population divergence, speciation and for conservation purposes. The freshwater ecosystems in Central Mexico are characterized by their genesis dynamism, destruction, and compartmentalization induced by intense geologic activity and climatic changes since the early Miocene. The endangered goodeid <it>Zoogoneticus quitzeoensis </it>is widely distributed across Central México, thus making it a good model for phylogeographic analyses in this area.</p> <p>Results</p> <p>We addressed the phylogeography, evolutionary history and genetic structure of populations of <it>Z. quitzeoensis </it>through a sequential approach, based on both microsatellite and mitochondrial cytochrome <it>b </it>sequences. Most haplotypes were private to particular locations. All the populations analysed showed a remarkable number of haplotypes. The level of gene diversity within populations was <inline-formula><m:math name="1471-2148-8-161-i1" xmlns:m="http://www.w3.org/1998/Math/MathML"><m:semantics><m:mover accent="true"><m:mi>H</m:mi><m:mo>¯</m:mo></m:mover><m:annotation encoding="MathType-MTEF"> MathType@MTEF@5@5@+=feaafiart1ev1aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9gBaebbnrfifHhDYfgasaacPC6xNi=xH8viVGI8Gi=hEeeu0xXdbba9frFj0xb9qqpG0dXdb9aspeI8k8fiI+fsY=rqGqVepae9pg0db9vqaiVgFr0xfr=xfr=xc9adbaqaaeGaciGaaiaabeqaaeqabiWaaaGcbaGafmisaGKbaebaaaa@2D06@</m:annotation></m:semantics></m:math></inline-formula>_{<it>d </it>}= 0.987 (0.714 – 1.00). However, in general the nucleotide diversity was low, π = 0.0173 (0.0015 – 0.0049). Significant genetic structure was found among populations at the mitochondrial and nuclear level (Φ_ST= 0.836 and <it>F</it>_{<it>ST </it>}= 0.262, respectively). We distinguished two well-defined mitochondrial lineages that were separated <it>ca</it>. 3.3 million years ago (Mya). The time since expansion was <it>ca</it>. 1.5 × 10⁶years ago for Lineage I and <it>ca</it>. 860,000 years ago for Lineage II. Also, genetic patterns of differentiation, between and within lineages, are described at different historical timescales.</p> <p>Conclusion</p> <p>Our mtDNA data indicates that the evolution of the different genetic groups is more related to ancient geological and climatic events (Middle Pliocene, <it>ca</it>. 3.3 Mya) than to the current hydrographic configuration of the basins. In general, mitochondrial and nuclear data supported the same relationships between populations, with the exception of some reduced populations in highly polluted basins (Lower Lerma River), where the effects of genetic drift are suggested by the different analyses at the nuclear and mitochondrial level. Further, our findings are of special interest for the conservation of this endangered species.</p

Do the Historical Biogeography and Evolutionary History of the Digenean Margotrema spp. across Central Mexico Mirror Those of Their Freshwater Fish Hosts (Goodeinae)?

Host-parasite systems provide an ideal platform to study evolution at different levels, including codivergence in a historical biogeography context. In this study we aim to describe biogeographic and codivergent patterns and associated processes of the Goodeinae freshwater fish and their digenean parasite (Margotrema spp.) over the last 6.5 Ma (million years), identifying the main factors (host and/or hydrogeomorphology) that influenced the evolution of Margotrema. We obtained a species tree for Margotrema spp. using DNA sequence data from mitochondrial and nuclear molecular markers (COI and ITS1, respectively) and performed molecular dating to discern divergence events within the genus. The dispersal-extinction-cladogenesis (DEC) model was used to describe the historical biogeography of digeneans and applied to cophylogenetic analyses of Margotrema and their goodeine hosts. Our results showed that the evolutionary history of Margotrema has been shaped in close association with its geographic context, especially with the geological history of central Mexico during the Pleistocene. Host-specificity has been established at three levels of historical association: a) Species-Species, represented by Xenotaenia resolanae -M. resolanae exclusively found in the Cuzalapa River Basin; b) Species-Lineage, represented by Characodon audax-M. bravoae Lineage II, exclusive to the Upper and Middle Mezquital River Basin, and c) Tribe-Lineage, including two instances of historical associations among parasites and hosts at the taxonomical level of tribe, one represented by Ilyodontini-M. bravoae Lineage I (distributed across the Ayuquila and Balsas River Basins), and another comprised of Girardinichthyini/Chapalichthyini-M. bravoae Lineage III, found only in the Lerma River Basin. We show that the evolutionary history of the parasites is, on several occasions, in agreement with the phylogenetic and biogeographic history of their hosts. A series of biogeographic and host-parasite events explain the codivergence patterns observed, in which cospeciation and colonisation via host-switching and vicariant plus dispersal events are appreciated, at different times during the diversification history of both associates, particularly during the Pleistocene.Facultad de Ciencias Naturales y Muse

Haliotrematoides spp. (Monogenoidea: Dactylogyridae) parasitizing Lutjanus guttatus (Lutjanidae) in two localities of the Pacific coast of Mexico, and their phylogenetic position within the Ancyrocephalinae through sequences of the 28S rRNA

AbstractSpecimens of wild populations of the spotted rose snapper, Lutjanus guttatus (Steindacher) were studied for monogenean parasites in 2 localities along the Mexican Pacific coast (Mazatlán, Sinaloa and Chamela Bay, Jalisco). Five species of dactylogyrids were found on the gills of their hosts: Haliotrematoides guttati (García-Vargas, Fajer-Ávila, & Lamothe-Argumedo, 2008), H. plectridium Kristky and Mendoza-Franco in Kritsky, Tingbao, & Yuan, 2009, H. spinatus Kristky and Mendoza-Franco in Kritsky et al. (2009), Euryhaliotrema perezponcei García-Vargas, Fajer-Ávila & Lamothe-Argumedo, 2008 and E. mehen (Soler-Jiménez, García-Gasca, & Fajer-Avila, 2012). Freshly collected specimens provided an opportunity to study and compare specimens from different localities in further detail and few morphological characters were added to the description of each species. Additionally, a fragment of 856bp of the 28S ribosomal RNA (D1–D3) was obtained for all the sampled monogeneans, and a phylogenetic analysis along with all available sequences of dactylogyrids was conducted to establish the systematic position of the species within the Ancyrocephalinae. Our results suggest that species of Haliotrema might be included in Haliotrematoides genus. In addition, the genetic divergence data suggest that H. guttati and H. spinatus may represent a species complex; however, this asseveration needs additional data

Morphology and Sequence Data of Mexican Populations of the Ciliate Parasite of Marine Fishes Trichodina rectuncinata (Ciliophora: Trichodinidae)

Trichodina rectuncinata is one of the trichodinids most widely distributed in marine fish. This ciliate species has been recorded in more than 20 host species belonging to 17 fish families worldwide. Previous comparative studies based on morphometric data revealed considerable morphological variation among specimens from different populations of T. rectuncinata. In this study, we conducted a morphometric- molecular analysis of three populations of T. rectuncinata to evaluate potential differences among 18S rRNA sequences, in relation to morphological variations. Smears were obtained from marine fishes in three localities along the Pacific coast of Mexico. Based on the shape of denticles, we found four different morphotypes for T. rectuncinata. This morphological variability does not correspond with the genetic divergence, suggesting that all analyzed populations belong to the same species. Further analyses using more variable markers are necessary to corroborate the findings of our study.Fil: Islas Ortega, Alma G.. Universidad Nacional Autónoma de México; MéxicoFil: Aguilar Aguilar, Rogelio. Universidad Nacional Autónoma de México; MéxicoFil: Marcotegui, Paula Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Martorelli, Sergio Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Hernández Mena, David. Universidad Nacional Autónoma de México; MéxicoFil: Pérez Ponce de León, Gerardo. Universidad Nacional Autónoma de México; Méxic

Morphology and Sequence Data of Mexican Populations of the Ciliate Parasite of Marine Fishes Trichodina rectuncinata (Ciliophora: Trichodinidae)

Trichodina rectuncinata is one of the trichodinids most widely distributed in marine fish. This ciliate species has been recorded in more than 20 host species belonging to 17 fish families worldwide. Previous comparative studies based on morphometric data revealed considerable morphological variation among specimens from different populations of T. rectuncinata. In this study, we conducted a morphometric- molecular analysis of three populations of T. rectuncinata to evaluate potential differences among 18S rRNA sequences, in relation to morphological variations. Smears were obtained from marine fishes in three localities along the Pacific coast of Mexico. Based on the shape of denticles, we found four different morphotypes for T. rectuncinata. This morphological variability does not correspond with the genetic divergence, suggesting that all analyzed populations belong to the same species. Further analyses using more variable markers are necessary to corroborate the findings of our study.Centro de Estudios Parasitológicos y de Vectore

Morphology and Sequence Data of Mexican Populations of the Ciliate Parasite of Marine Fishes Trichodina rectuncinata (Ciliophora: Trichodinidae)

Trichodina rectuncinata is one of the trichodinids most widely distributed in marine fish. This ciliate species has been recorded in more than 20 host species belonging to 17 fish families worldwide. Previous comparative studies based on morphometric data revealed considerable morphological variation among specimens from different populations of T. rectuncinata. In this study, we conducted a morphometric- molecular analysis of three populations of T. rectuncinata to evaluate potential differences among 18S rRNA sequences, in relation to morphological variations. Smears were obtained from marine fishes in three localities along the Pacific coast of Mexico. Based on the shape of denticles, we found four different morphotypes for T. rectuncinata. This morphological variability does not correspond with the genetic divergence, suggesting that all analyzed populations belong to the same species. Further analyses using more variable markers are necessary to corroborate the findings of our study.Centro de Estudios Parasitológicos y de Vectore

Trematode Diversity in Freshwater Fishes of the Globe II: “New World”

We provide a summary overview of the diversity of trematode parasites in freshwater fishes of the “New World,” i.e. the Americas, with emphasis on adult forms. The trematode fauna of three regions, South America, Middle America, and USA and Canada (North America north of Mexico), are considered separately. In total, 462 trematode species have been reported as adults from the Americas. The proportion of host species examined for parasites varies widely across the Americas, from a high of 45% in the Mexican region of Middle America to less than 5% in South America. North and South America share no adult species, and one exclusively freshwater genus, Creptotrema Travassos, Artigas & Pereira, 1928 in the Allocreadiidae Looss, 1902 is the most widely distributed. Metacercariae of strigeiforms maturing in fish-eating birds (e.g., species of the Diplostomidae Poirier, 1886) are common and widely distributed. The review also highlights the paucity of known life-cycles. The foreseeable future of diversity studies belongs to integrative approaches and the application of molecular ecological methods. While opportunistic sampling will remain important in describing and cataloguing the trematode fauna, a better understanding of trematode diversity and biology will also depend on strategic sampling throughout the Americas