Balancing genetic uniqueness and genetic variation in determining conservation and translocation strategies: a comprehensive case study of threatened dwarf galaxias,Galaxiella pusilla (Mack) (Pisces: Galaxiidae)

Genetic markers are widely used to define and manage populations of threatened species based on the notion that populations with unique lineages of mtDNA and well‐differentiated nuclear marker frequencies should be treated separately. However, a danger of this approach is that genetic uniqueness might be emphasized at the cost of genetic diversity, which is essential for adaptation and is potentially boosted by mixing geographically separate populations. Here, we re‐explore the issue of defining management units, focussing on a detailed study of Galaxiella pusilla, a small freshwater fish of national conservation significance in Australia. Using a combination of microsatellite and mitochondrial markers, 51 populations across the species range were surveyed for genetic structure and diversity. We found an inverse relationship between genetic differentiation and genetic diversity, highlighting a long‐term risk of deliberate isolation of G. pusilla populations based on protection of unique lineages. Instead, we adopt a method for identifying genetic management units that takes into consideration both uniqueness and genetic variation. This produced a management framework to guide future translocation and re‐introduction efforts for G. pusilla, which contrasted to the framework based on a more traditional approach that may overlook important genetic variation in populations.     

Molecular phylogeny and phylogeography of the Australian freshwater fish genus Galaxiella, with an emphasis on dwarf galaxias (G. pusilla)

The freshwater fauna of Southern Australia is primarily restricted to the southwestern and southeastern corners of the continent, and is separated by a large, arid region that is inhospitable to this biota. This geographic phenomenon has attracted considerable interest from biogeographers looking to explain evolutionary diversification in this region. Here, we employed phylogenetic and phylogeographic approaches to evaluate the effect of this barrier on a group of four galaxiid fish species (Galaxiella) endemic to temperate Southern Australia. We also tested if continental shelf width has influenced connectivity among populations during low sea levels when rivers, now isolated, could have been connected. We addressed these questions by sampling each species across its range using multiple molecular markers (mitochondrial cytochrome b sequences, nuclear S7 intron sequences, and 49 allozyme loci). These data also allowed us to assess species boundaries, to refine phylogenetic affinities, and to estimate species ages. Interestingly, we found compelling evidence for cryptic species in G. pusilla, manifesting as allopatric eastern and western taxa. Our combined phylogeny and dating analysis point to an origin for the genus dating to the early Cenozoic, with three of the four species originating during the Oligocene-Miocene. Each Galaxiella species showed high levels of genetic divergences between all but the most proximate populations. Despite extensive drainage connections during recent low sea levels in southeastern Australia, populations of both species within G. pusilla maintained high levels of genetic structure. All populations experienced Late Pleistocene-Holocene population growth, possibly in response to the relaxation of arid conditions after the last glacial maximum. High levels of genetic divergence and the discovery of new cryptic species have important implications for the conservation of this already threatened group of freshwater species.     

Helminth parasites of Chapalichthys encaustus (Pisces: Goodeidae), an endemic freshwater fish from Lake Chapala, Jalisco, Mexico

A total of 6 helminth species were recorded during helminthological examination of 50 Chapalichthys encaustus from Lake Chapala, Jalisco, Mexico. Helminth species identified included: Salsuginus sp. (an undescribed monogenea); Posthodiplostomum minimum (metacercariae); Cyclustera ralli (metacestode); Polymorphus brevis (cystacanth); Contracaecum sp. (nematode larvae); and Rhabdochona lichtenfelsi (adult nematode). Of these, 2 (Salsuginus sp. and R. lichtenfelsi) are specialist species. The observed species richness, individual parasite abundance, and diversity were low. Data suggest that host specificity is an important factor contributing to observed community composition and richness. Host feeding habits and helminth species availability seem to determine the characteristics of these helminth assemblages.     

Cardiac function of two ecologically distinct Neotropical freshwater fish: Curimbata, Prochilodus lineatus (Teleostei, Prochilodontidae), and trahira, Hoplias malabaricus (Teleostei, Erythrinidae)

An isometric muscle preparation was used to investigate the importance of the ventricular sarcoplasmic reticulum (SR) and extracellular Ca(2+) (2.5 up to 10.5 mM) to force generation at 25 degrees C (acclimation temperature) in two ecologically distinct Neotropical teleost fish: Curimbata (active species), and trahira (sedentary species). The post-rest force was studied with and without 10 muM ryanodine in the medium. The positive inotropism observed for both species in response to increases on extracellular Ca(2+) reflected a greater Ca(2+) influx through sarcolemma, as well as an increase in Ca(2+) liberation from the SR by the Ca(2+)-induced Ca(2+) release mechanism. The significant post-rest potentiation recorded for the curimbata and trahira control preparations (3.22+/-0.24 to 6.55+/-0.77 mN mm(-2) and 0.74+/-0.07 to 2.26+/-0.26 mN mm(-2), respectively), was completely inhibited by the addition of ryanodine to the bathing medium, suggesting a potential functionality of SR for both species. Considering the differences in these species habitats, modes of life and levels of activity and the fact of a probable SR Ca(2+) cycling in a physiological temperature, we suggest that the functionality of the SR in these species is probably related to their phylogeny.     

High genetic diversity within the morphologically conservative dwarf loach, Kichulchoia brevifasciata (Teleostei: Cobitidae), an endangered freshwater fish from South Korea

The dwarf loach, Kichulchoia brevifasciata, is a primary freshwater fish endemic to South Korea (Republic of Korea). Due to its limited geographic range, special habitat requirements, and scarcity, this species has been considered one of the most endangered cobitid loaches in the world. Gene tree and species tree reconstruction derived from mitochondrial and nuclear sequence data supports the exclusivity of K. brevifasciata and the existence of two highly distinct genetic lineages (eastern and western lineages). Intraspecific genetic variation based on the corrected genetic distance ranged from 0.0013 to 0.0017 (cytochrome b) and 0–0.0012 (nuclear loci) within each lineage and 0.0349 (cytochrome b) and 0.0037–0.0104 (nuclear loci) between the lineages. Although morphologically homogeneous, eastern and western lineages were estimated to have diverged roughly 2.79 million years ago (4.25–1.42, 95 % HPD). Future conservation efforts for K. brevifasciata should consider these genetically distinct lineages as separate evolutionary entities and adopt conservation efforts accordingly.     

Haematological parameters in a neotropical fish, Corydoras paleatus (Jenyns, 1842) (Pisces, Callichthyidae), captured from pristine and polluted water

We report normal ranges of haematological indices in healthy Corydoras paleatus from an unpolluted area. Haematological parameters studied include: erythrocyte counts (Er), haematocrit (Ht), haemoglobin concentration (Hb), mean cell volume (MCV), mean cell haemoglobin (MCH) and mean cell haemoglobin concentration (MCHC). Normal red blood parameters did not change according to maturation stages, sex or seasons. Then, we compared them with those coming from fish captured in a site polluted by sewage. Fish exposed to pollution presented significantly higher values of Er, Ht, Hb, MCH and MCHC than those captured in an unpolluted area. Discriminant analysis showed that Hb is a key parameter to point out differences between populations exposed to different environmental conditions. We suggest that haematological values of C. paleatus, registered during this study, could be used as biomarkers in future works evaluating the incidence of environmental stress on fish as well as pointing out changes in the water quality.     

Redescription and molecular characterization of two Trichodina species (Ciliophora,Peritrichia, Mobilida) from freshwater fish in China

During an investigation of parasitic ciliates in northern China, two Trichodina species, T. acuta Lom, 1970 and T. nigra Lom, 1960, were isolated from the freshwater fish Cyprinus carpio Linnaeus, 1758. The morphology of each species was investigated based on dry silver nitrate-stained specimens. In addition, the molecular phylogeny of each was analyzed based on small subunit ribosomal DNA (SSU rDNA) sequence data. Trichodina acuta can be distinguished from its congeners by the undefined periphery of the central circle, the distinct gap between the rays and the central circle, and the distinctly sickle-shaped blades. Trichodina nigra is a cosmopolitan ciliate and is characterized by its densely linked denticles, broad, rounded spatula-shaped blades, robust central parts, and well developed rays. Phylogenetic analyses revealed that T. acuta and T. nigra nest within different clades, supporting the assertion that the GC content of SSU rDNA sequences could reflect evolutionary relationships among Trichodina species.     

Population structure and reproductive biology of a freshwater fish,Labeo boggut (Sykes, 1839), from two perennial rivers of Yamuna basin

Population structure and reproductive biology of an important and less studied freshwater carp, Labeo boggut (Sykes, 1839), from two perennial rivers of Central India were studied between January 2008 and December 2009. Maximum three annual rings were found and used to assess growth data in samples representing 0 to 3+ year classes. LWR indicated positive allometric growth in males and females of both rivers. Asymptotic length (L_∞) and growth co‐efficient (K) were 22.5 cm and 0.5 year^?1 for the Betwa River; and 23.6 cm and 0.6 year^?1 for the Ken River. Growth performance index (ø’) was higher in the Ken than in the Betwa. Reproduction was between June and September and GSI of both sexes were maximal in mid‐June, thereafter declining until September. Mean size at first sexual maturity was 12.2 cm (n = 12) for females and 13.2 cm (n = 8) for males in the Betwa, and 12.5 cm (n = 13) TL for females and 13.1 cm (n = 9) TL for males in the Ken. The exploitation level (E) and maximum allowable exploitation (E_max) limit of L. boggut was 0.23 and 0.36 in the Betwa, whereas it was 0.33 and 0.37 in the Ken. These presented biological traits and population characters of L. boggut from both rivers provide first basic information for use in future assessment and conservation planning.     

Galaxitaenia toloi n. gen., n. sp. (Eucestoda: Pseudophyllidea) from Galaxias platei (Pisces: Osmeriformes, Galaxiidae), in the Patagonian region of Argentina

Galaxitaenia n. gen. (Eucestoda: Pseudophyllidea) is proposed to accommodate Galaxitaenia toloi n. gen., n. sp. from Galaxias platei, a freshwater fish inhabiting Andean lakes in Argentine Patagonia. Galaxitaenia belongs to the Triaenophoridae because it possesses a marginal genital pore, a ventral uterine pore, and a follicular vitelline gland. The new genus can be distinguished from other triaenophorids by the following combination of characters: a scolex with a prominent rectangular apical disc without hooks, grooves, or indentations; neck present; segments wider than long to quadrangular; testes in 2 lateral fields, often connected anteriorly; cirrus unarmed; an ovary situated posteriorly; a vagina posterior to the cirrus sac; vitelline follicles medullary, in 2 ventral fields forming 2 wings interrupted medially; a uterus saccate to branched; and eggs without operculum. The types, distribution, and density of microtriches were analyzed on the surface of the tegument of scolex, neck, and immature segments. The presence of tumuli were observed on the apical disc of the scolex. Galaxitaenia toloi n. sp. is the first triaenophorid species recorded in a South American freshwater fish and the fourth helminth parasitizing the intestine of G. platei.     

Redescription of Marstonia comalensis (Pilsbry & Ferriss, 1906), a poorly known and possibly threatened freshwater gastropod from the Edwards Plateau region (Texas)

Marstonia comalensis, a poorly known nymphophiline gastropod (originally described from Comal Creek, Texas) that has often been confused with Cincinnatia integra, is re-described and the generic placement of this species, which was recently allocated to Marstonia based on unpublished evidence, is confirmed by anatomical study. Marstonia comalensis is a large congener having an ovate-conic, openly umbilicate shell and penis having a short filament and oblique, squarish lobe bearing a narrow gland along its distal edge. It is well differentiated morphologically from congeners having similar shells and penes and is also genetically divergent relative to those congeners that have been sequenced (mtCOI divergence 3.0-8.5%). A Bayesian analysis of a small COI dataset resolved Marstonia comalensis in a poorly supported sub-clade together with Marstonia hershleri, Marstonia lustrica and Marstonia pachyta. The predominantly new records presented herein indicate that Marstonia comalensis was historically distributed in the upper portions of the Brazos, Colorado, Guadalupe and Nueces River basins, south-central Texas. The species has been live collected at only 12 localities and only two of these have been re-visited since 1993. These data suggest that the conservation status of this snail, which has a critically imperiled (G1) NatureServe ranking and was recently proposed for federal listing, needs to be re-assessed.     

Two new species of Gyrodactylus von Nordmann, 1832 (Monogenea: Gyrodactylidae) parasitizing Girardinichthys multiradiatus (Cyprinodontiformes: Goodeidae), an endemic freshwater fish from central Mexico

Gyrodactylus mexicanus n. sp. and Gyrodactylus lamothei n. sp. are described from the fins and skin of Girardinichthys multiradiatus, an endemic freshwater fish from central Mexico. Gyrodactylus mexicanus is compared to other Gyrodactylus species that parasitize Fundulus spp., the phylogenetically closest group to the Goodeidae from North America. Gyrodactylus mexicanus is distinguished by having large anchors with well-developed superficial roots, enlarged hooks with a proximally disrupted shank (ligament), and a ventral bar with 2 poorly developed anterolateral projections and a small medial process. Gyrodactylus lamothei is distinguished from G. mexicanus and from other species of Gyrodactylus on the North American continent by having anchors with a sclerite on the superficial root and robust hooks with a straight shaft and a recurved point.     

Phylogenies of the Frigatebirds (Fregatidae) and Tropicbirds (Phaethonidae), two divergent groups of the traditional order Pelecaniformes, inferred from mitochondrial DNA sequences

The frigatebirds (Fregatidae) and Tropicbirds (Phaethonidae) represent the most morphologically and behaviorally distinct members of the traditional Order Pelecaniformes. Using 1756bp of mitochondrial DNA sequence consisting of the 12S, ATPase-6, ATPase-8, and COI genes obtained from all extant species, we derive a completely resolved phylogeny for both groups. The inferred relationships among these species are robust to the method of phylogenetic estimation used, and all branches are well supported, in spite of the relatively recent radiation within the frigatebirds. The two families are not closely related either to each other, or to any other putative relatives (e.g., pelicans; Pelecanidae).     

Ten novel microsatellite markers for the freshwater sleeper Micropercops swinhonis (Günther, 1873), with testing of cross‐species amplification in two other fishes from suborder Gobioidei

Ten novel polymorphic microsatellite loci were developed for the freshwater sleeper Micropercops swinhonis, a relatively abundant and broadly distributed lake‐dwelling fish in Asia, using next generation sequencing. These markers were tested in a population of 48 individuals, and characteristics suggest that they may be useful for population genetic studies. The average number of alleles per marker was 6.6 (range: 2–26), the average expected heterozygosity was 0.55 (range: 0.081–0.955), and the average polymorphic information content value per marker was 0.507 (range: 0.077–0.942). No marker showed significant deviation from Hardy‐Weinberg Equilibrium following Bonferroni correction of significance values, and no markers showed evidence of null alleles, large allele dropout, or scoring errors from stutter bands. Two markers had successful amplification in Odontobutis potamophila, and one marker had successful amplification in Rhinogobius giurinus. These novel markers may be useful for further research in population genetic studies involving M. swinhonis.     

Description of Auriculotrema lechneri n. gen., n. sp. (Digenea: Choanocotylidae), a parasite of freshwater turtles (Testudines: Pleurodira: Chelidae) from Queensland,Australia

Auriculotrema lechneri n. gen., n. sp. is described from the small intestine of Emydura krefftii and Elseya latisternum from northern Queensland, Australia. The new species strongly resembles species of Choanocotyle in body shape, ventral incision of the oral sucker, structure of the cirrus sac, and location of the genital pore. The distinctive taxonomic feature is the presence of 2 winglike projections extending beyond the lateral margins of the oral sucker, in contrast to the extremely large, expanded oral sucker diagnostic of Choanocotyle spp. Auriculotrema n. gen. is the second genus included in the formerly monotypic Choanocotylidae Jue Sue and Platt, 1998.     

Evolutionary relationships among hares from North Africa (Lepus sp. or Lepus spp.), cape hares (L. capensis) from South Africa, and brown hares (L. europaeus), as inferred from mtDNA PCR-RFLP and allozyme data

Systematics and taxonomy of hares of the genus Lepus (Lagomorpha) are under contentious debate, and phylogenetic relationships among many taxa are not well understood. Here we study genetic differentiation and evolutionary relationships among North African hares, currently considered subspecies of Lepus capensis , cape hares ( L. capensis ) from the Cape province in South Africa, and brown hares ( L. europeaus ) from Europe and Anatolia, using maternally (mtDNA) and biparentally (allozymes) inherited markers. A polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of a c. 1.8 kb long segment of the mitochondrial control region using eight hexanucleotide-recognizing restriction endonucleases yielded 28 haplotypes, and horizontal starch gel electrophoresis of proteins encoded by 25 structural gene loci revealed 52 alleles at 18 polymorphic loci. Diverse phylogenetic analyses (neighbor joining dendrogram, median joining network, multidimensional scaling of pairwise distances, AMOVA, F -statistics, hierarchical F -statistics) of genetic variants revealed marked substructuring of mtDNA into three phylogeographic groups, namely an African, a central European, and an Anatolian, but a somewhat less pronounced overall differentiation of the nuclear genome, despite a relatively high number of population-specific (private) alleles. However, all our results are not incongruent with Petter's (1959: Mammalia 23 , 41; 1961: Z. f. Säugetierkunde 26 , 30; 1972 : Société Des Sciences Naturelles et Physiques du Maroc 52 , 122) hypothesis that North African hares generally belong to L. capensis and that brown hares should be included in this species as well.     

Polymorphisms at two enzyme loci (Sod and Odh) in populations of the Amur sleeper,Perccottus glenii (Pisces,Eleotrididae), from its native range and the colonized area: the effect of introduction on genetic variation

In the first half of the 20th century small founder groups of the Amur sleeper, Perccottus glenii, have been transferred from their native range in the Far East to some regions of the European part of Russia. In order to investigate the consequences of the introductions, 15 Far East populations and 11 European populations, that originated from two transfers, were studied for their variability on two enzyme loci (Sod and Odh) using polyacrylamide gel electrophoresis. For both loci, divergence between populations and heterozygosity in the populations were higher in the colonized regions than in the native range. Heterozygote advantage in small founder populations seems to be a factor resisting genetic drift and determining the changes observed in the genetic structure of the introduced populations.     

Description of Buckarootrema goodmani n. g., n. sp. (Digenea: Pronocephalidae), a parasite of the freshwater turtle Emydura macquarii (Gray, 1830) (Pleurodira: Chelidae) from Queensland, Australia, and a phylogenetic analysis of the genera of the Pronocephalidae Looss, 1902.

Buckarootrema goodmani n. g., n. sp. is described from the small intestine of the Murray turtle, Emydura macquarii (Gray, 1830), from the vicinity of Warwick, Queensland, Australia. The distinctive taxonomic features include the vitellarium, which consists of 2 compact masses directly anterior to and occasionally overlapping the testes; the uterus with extensive pre- and postovarian coils; intestinal ceca with small, medial diverticula that terminate anterior to or at the anterior margin of the testes; a comma-shaped cirrus sac with both internal and external seminal vesicles. Phylogenetic systematic analysis of the genera of the Pronocephalidae including Buckarootrema and Notopronocephalus, the only other genus of pronocephalids reported from Australian freshwater turtles, indicates that Buckarootrema is the sister taxon of Neopronocephalus and Notopronocephalus is the sister group of the rest of the Pronocephalinae.     

Light and electron microscopical data on the spores of <Emphasis Type="Italic">Thelohanellus rhabdalestus</Emphasis> n. sp. (Myxozoa: Myxosporea), a parasite of a freshwater fish from the Kwanza River,Angola

The myxosporean Thelohanellus rhabdalestus n. sp. (Myxozoa: Bivalvulida), a parasite of the freshwater fish Rhabdalestes maunensis (Fower) collected from the Kwanza River, Angola, is described based on light and electron microscopical studies. The parasite occurs in irregular, milky-whitish, cyst-like plasmodia (up to 0.8 mm in diameter) in close contact with the liver and heart. The spores are pyriform, with slight tapering anterior and round posterior ends, and measure 16.8 ± 0.5 μm (n = 50) long, 10.2 ± 0.6 μm (n = 50) wide and 5.6 ± 0.8 μm (n = 25) thick. The spore wall is partly surrounded by a discontinuous, closely adhered, external coat of electron-dense material of variable thickness (up to c.35 nm). A single flask-shaped polar capsule [7.2 ± 0.3 μm (n = 50) long and 4.0 ± 0.4 μm (n = 50) in diameter] lies close to the apex of the spores and contains a polar filament with six or seven (rarely eight) coils oblique to its longitudinal axis. Based on morphological and ultrastructural differences, compared with other members of Thelohanellus Kudo, 1933, and judging from the host-specificity of previously described species, we consider this species new to science. This is the first reported myxosporean from the Angolan fauna.