Phylogenetic relationships among atheriniform fishes (Teleostei: Atherinomorpha)

We present evidence from adult and larval morphology for the monophyly and relationships of Atheriniformes, using other atherinomorphs, mugilids and acanthomorph fishes as outgroups. Atheriniformes is diagnosed by ten characters (larval: short preanal length, single mid-dorsal row of melanophores; adult: vomerine ventral face concave, long Al muscle tendon to lacrimal, two anterior infraorbital bones, pelvic-rib ligament, pelvic medial plate not extended to anterior end, and second dorsal-fin spine flexible). We recognize six families within the order, the hierarchical relationships among which are: (Atherinopsidae (Notocheiridae (Melanotaeniidae (Atherionidae (Phallostethidae, Atherinidae))))). Other major conclusions include: (1) Atherinopsidae (Menidiinae, Atherinopsinae) is diagnosed by 20 characters (e.g. ethmomaxillary ligament attached to palatine dorsal process, ventral postcleithrum with two dorsal rami); (2) Melanotaeniidae (Bedotiinae (Melanotaeniinae (Telmatherinini, Pseudomugilini))) is diagnosed by six characters (e.g. absence of second dorsal-fin spine, sexual dimorphism in body colour and median-fin development, greater body depth); (3) Dentatherina is in Phallostethidae; (4) Atherinidae (Atherinomorinae (Craterocephalinae, Atherininae)) is diagnosed by three characters (lacrimal notch, ventral postcleithrum between first and second pleural ribs, pelvic ventral spine); (5) Atherinidae and Phallostethidae form the Atherinoidea clade diagnosed by seven characters (e.g. interopercle dorsal process absent, dorsal wings of urohyal absent, ventral postcleithrum laminar, pelvic medial plate extended to anterior end, presence of anal plate). Bedotia, Rhodes , and melanotaeniines are shown to be derived within atheriniforms rather than the plesiomorphic sister groups to a paraphyletic 'atherinoid' group. We also demonstrate that groups traditionally placed in Atherinidae (Menidiinae, Atherininae, Atherioninae, etc.) comprise a paraphyletic assemblage.     

Phylogenetic inference in Odontesthes and Atherina (Teleostei: Atheriniformes) with insights into ecological adaptation

This contribution provides an insight into Atheriniformes systematics based on four mitochondrial regions: 12S rRNA, cytb, COI and control region (2794bp in total). In the Atherinopsoidei (New World silversides), comparisons among five species of Odontesthes, O. argentinensis, O. bonariensis, O. smitti, O. hatcheri and O. incisa revealed a putative marine-freshwater pairing pattern of Odontesthes species, possibly driven by sea level fluctuations of South American waters. This study represents the first data on molecular phylogeny of Odontesthes species that can be of usefulness to biodiversity conservation policies. In the Atherinoidei (Old World silversides), Atherina boyeri was corroborated as a species complex constituted by a marine form, a marine with dark spots form and a brackish form. Concretely, Odontesthes and Atherina may represent geographically replicated models to study genetic adaptation and speciation of marine species to brackish and freshwater habitats. In addition, phylogenetic analyses supported Odontesthes and Atherina as monophyletic taxa and their separation into two differentiated suborders Atherinopsoidei and Atherinoidei, respectively.     

Beach Spawning in Fishes: Phylogenetic Tests of Hypotheses

Marine fishes that spawn at the water's edge or even out ofwater provide their eggs with the advantages of the warmer temperaturesand high oxygen availability of the high intertidal zone. However,they increase the risks of desiccation and terrestrial predation.Beach spawners are present in at least 6 families of teleostfishes. Two hypotheses about the origin of beach spawning aretested by mapping of reproductive habitat and spawning siteutilization onto phylogenies of two families that contain multiplespecies that spawn on beaches: Osmeridae, the smelts, and Atherinopsidae,the silversides. Our analysis suggests that beach spawning hasevolved repeatedly in certain lineages, and that its antecedentsare different for each family. Anadromy appears to have beenthe precursor for at least 3 different evolutionary originsof beach spawning in osmerids, while nearshore marine spawningin association with plant or gravel substrates was probablythe precursor for the atherinopsids. Phylogenetic analysis enablesus to reject or support specific evolutionary hypotheses foreach clade.     

Adaptive radiation and hybridization in Wallace's Dreamponds: evidence from sailfin silversides in the Malili Lakes of Sulawesi

Adaptive radiations are extremely useful to understand factors driving speciation. A challenge in speciation research is to distinguish forces creating novelties and those relevant to divergence and adaptation. Recently, hybridization has regained major interest as a potential force leading to functional novelty and to the genesis of new species. Here, we show that introgressive hybridization is a prominent phenomenon in the radiation of sailfin silversides (Teleostei: Atheriniformes: Telmatherinidae) inhabiting the ancient Malili Lakes of Sulawesi, correlating conspicuously with patterns of increased diversity. We found the most diverse lacustrine species-group of the radiation to be heavily introgressed by genotypes originating from streams of the lake system, an effect that has masked the primary phylogenetic pattern of the flock. We conclude that hybridization could have acted as a key factor in the generation of the flock's spectacular diversity. To our knowledge, this is the first empirical evidence for massive reticulate evolution within a complex animal radiation.     

Implications of climate change for the reproductive capacity and survival of New World silversides (family Atherinopsidae)

The New World silversides (family Atherinopsidae) are found in marine, estuarine and inland waters of North, Central and South America, where they are ecologically important as forage fishes and sometimes economically important for commercial and recreational fisheries. This report reviews the knowledge of the reproductive attributes of temperate and subtropical atherinopsids in relation to temperature and discusses the potential effects of climate change on their reproduction and adaptive responses. Their reproductive cycles are primarily entrained by photoperiod with high temperature acting as a limiting factor. They are generally multiple spawners which release successive batches of eggs in spring, but some species can spawn also in autumn and even summer when temperatures do not increase excessively. The decoupling of temperature patterns and photoperiod with further global warming and associated asymmetric thermal fluctuations could lead to spawning at times or temperatures that are unsuitable for larval development and growth. Many members of this family show temperature-dependent sex determination (TSD), where the phenotypic sex of an individual is determined partly or wholly by the temperature experienced during gonadal sex differentiation, and high-temperature induced germ cell degeneration and decreased fertility. The predicted short-term reproductive responses of atherinopsids to climate change therefore include acceleration, shortening or overall disruption of spawning activity, and also more subtle, but nonetheless equally population-threatening, dysfunctions such as highly skewed sex ratios and partial or total loss of fertility. In the case of species with TSD, asymmetric thermal fluctuations could also cause larvae to encounter temperatures lower than normal during early development and be feminized. Such dysfunctions have been documented already in natural populations but are confined so far to landlocked, inland water habitats, perhaps because they impose more severe thermal fluctuations and limitations to migration and dispersal. The severity and recurrence of these dysfunctions with further climate change will depend both on the magnitude, speed and pattern of change and on how much (or how fast) physiological and behavioural traits can evolve to match the new conditions imposed by the climate, which is largely unknown. In this regard, compelling evidence is shown that numerous traits, including the sex determination system, are capable of rapid evolution and could mitigate the negative effects of temperature increases on population viability in atherinopsids.     

Polyphyly of the mail-cheeked fishes (Teleostei: Scorpaeniformes): evidence from mitochondrial and nuclear sequence data

Mitochondrial and nuclear DNA sequence data for 105 acanthomorph taxa are analyzed to address questions of scorpaeniform monophyly and relationships. The combination of 3425 aligned base pairs from the mitochondrial small subunit rDNA (12S), large subunit rDNA (16S), and tRNA-Val and the nuclear large subunit rDNA (28S), histone H3, and TMO-4c4 loci are analyzed. Representatives of all scorpaeniform suborders and 32 of 36 scorpaeniform families are included with most suborders represented by multiple species. In addition to 69 scorpaeniform taxa, 36 outgroup taxa, including representatives of most families previously conjectured to be related to the Scorpaeniformes, are analyzed due to serious concerns of scorpaeniform monophyly. The traditionally recognized scorpaeniform fishes are recovered as polyphyletic. The 13 representatives of the Atheriniformes, Blennioidei, Gasterosteoidei, Grammatidae, Notothenioidei, Percidae, Trichodontidae, and Zoarcoidei included in the analysis are all nested within the least inclusive clade that includes all traditionally recognized scorpaeniforms. The scorpaenoid lineage is widely polyphyletic, and its intrarelationships differed significantly from previous hypotheses. The cottoid lineage is paraphyletic with only the presence of the Trichodontidae, as the sister-taxon of the Cottoidei, disrupting the traditional subordinal hypothesis of relationships.     

Molecular systematics of the Sordariales: the order and the family Lasiosphaeriaceae redefined

The Sordariales is a taxonomically diverse group that has contained from seven to 14 families in recent years. The largest family is the Lasiosphaer-iaceae, which has contained between 33 and 53 genera, depending on the chosen classification. To determine the affinities and taxonomic placement of the Lasiosphaeriaceae and other families in the Sordariales, taxa representing every family in the Sordariales and most of the genera in the Lasiosphaeriaceae were targeted for phylogenetic analysis using partial sequences of the large-subunit (LSU) nrDNA. Based on molecular data, only genera within the families Chaetomiaceae, Lasiosphaeriaceae and Sordariaceae are retained within the redefined Sordariales. The order is a coherent group with morphologies that vary along well-defined lines, including large ascomata with large-celled membraneous or coriaceous walls and ascospores that show variation on a distinctive developmental theme, often with appendages or sheaths. The paraphyletic chaetomiaceous complex and the strongly supported Sordariaceae are nested among taxa traditionally placed in the Lasiosphaeriaceae. Analyses also indicate that 11 genera belong in the paraphyletic lasiosphaeriaceous complex. These taxa share a similar developmental pattern in their ascospore morphology that extends to the Sordariales as a whole. Based on these similarities in morphology, 13 additional genera are retained within the lasiosphaeriaceous complex and more than 35 genera have relationships in the order overall. Based on LSU data, 17 genera that have been assigned to the Lasiosphaeriaceae sensu lato are transferred to other families outside the Sordariales and 22 additional genera with differing morphologies subsequently are transferred out of the order. Two new orders, Coniochaetales and Chaetosphaeriales, are recognized for the families Coniochaetaceae and Chaetosphaeriaceae respectively. The Boliniaceae is accepted in the Boliniales, and the Nitschkiaceae is accepted in the Coronophorales. Annulatascaceae and Cephalothecaceae are placed in Sordariomycetidae inc. sed., and Batistiaceae is placed in the Euascomycetes inc. sed.     

Phylogeny of major lineages of suboscines (Passeriformes) analysed by nuclear DNA sequence data

Phylogenetic relationships among major groups of passeriform birds were studied by analyses of nucleotide sequence data from two nuclear genes, c- myc and RAG-1. The results corroborated both the monophyly of the order Passeriformes, and the major dichotomy into oscine and suboscine passerines previously suggested based on syringeal morphology and DNA-DNA hybridizations. The representatives of the Old World suboscines (families Eurylaimidae, Philepittidae and Pittidae) formed a monophyletic clade. The New World suboscines clustered into two clades. The first contained Conopophaga (Conopophagidae), Furnarius (Furnariidae), Lepidocolaptes (Dendrocolaptidae), Thamnophilus (Formicariidae), and Rhinocrypta (Rhinocryptidae). Previously, the monophyly of this group has been inferred from their possession of a unique, "tracheophone" syrinx, and from DNA-DNA hybridisation data. The second clade of New World suboscines includes Gubernetes and Muscivora (Tyrannidae), Phytotoma (Phytotomidae), Tityra (Cotingidae) and Pipra (Pipridae). This group of families have been considered monophyletic based on morphology (although ambiguously) and DNA-DNA hybridisation. The sister group relationship of Tityra and Phytotoma supports the previously supposed cotingid affinity of Phytotoma . Nuclear DNA data also unambiguously group the lyrebirds Menura with the oscines.
The presented results from the analysis of nuclear DNA agree well with morphology and DNA-DNA hybridisation data. The precise age of the divergences studied herein are unknown but based on interpretations of the fossil record of passerine birds many of them might date back to the early Tertiary. The agreement between data from the nuclear DNA and other sources, along with the fact that neither of the studied genes showed sign of saturation, indicate the great potential of these two nuclear genes to resolve very old divergences in birds.     

Mechanisms of the jaws of some atheriniform fish

The Atheriniformes is an order of teleost fish which consists of the Atherinoidei (sand smelts etc.), Cyprinodontoidei (tooth-carps) and Exocoetoidei (halfbeaks etc.). Some of its members have protrusible upper jaws and some do not. Photographs have been taken of two species of Cyprinodontoidei feeding, to discover how they use their jaws, which are protrusible. The anatomy and mechanisms of the jaws of these and of various other Atheriniformes have been studied. The terminology of the kinematics of machines is used in a general discussion of the mechanisms of teleost jaws. Anatomical similarities between the jaws of Acanthopterygii, Cyprinoidei and Atheriniformes are noted and discussed.     

A new Huffmanela species (Nematoda: Trichosomoididae) parasitizing atherinid fishes in north Patagonian Gulfs, Argentina

Huffmanela moraveci n. sp. (Nematode: Trichosomoididae) is described from the skin of fins and gills of the silversides Odontesthes smitti Lahille, 1949, and Odontesthes nigricans Richardson, 1848 (Pisces: Atheriniformes), from southwestern Atlantic coast, on the basis of the morphology of adults and eggs found in the host tissues. Huffmanela moraveci n. sp. can be distinguished from Huffmanela carcharini, H. banningi, H. japonica, H. mexicana, H. paronai, H. schouteni, H. shikokuensis, H. branchialis, H. filamentosa, H. ossicola, and H. lata by the size and shape of the eggs. The adult stage of H. moraveci n. sp. can be differentiated from H. hufmani and H. canadensis by the position of the nerve ring and by the total esophagus length/body length ratio. Huffmanela moraveci n. sp. also differs from H. huffmani by the presence of bacillary bands and by the body length. This is the first report of a species of Huffmanela in South America, the first report of a species of Huffmanela with Odontesthes spp. as host, and the third known adult form in the genus.     

Using zebrafish to investigate cypriniform evolutionary novelties: functional development and evolutionary diversification of the kinethmoid

Although the zebrafish has become a popular model organism for biomedical studies, we propose that the wealth of morphological novelties that characterize this cypriniform fish makes it well suited for investigating the development of evolutionary innovations. Morphological novelties associated with feeding in cypriniform fishes include: a unique structure of the pharyngeal jaws in which the lower pharyngeal jaws are enlarged and opposed to a pad on the basioccipital process; a palatal organ found on the roof of the buccal chamber that is thought to help process detrital food within the buccal chamber; and, the kinethmoid, a novel ossification that effects a unique means of premaxillary protrusion. We present new morphological and developmental data and review functional data regarding the role of the kinethmoid in premaxillary protrusion in the zebrafish. Premaxillary protrusion plays an important role in effective prey acquisition in teleosts and the evolution of a unique means of premaxillary protrusion within Cypriniformes may have led to a number of trophic radiations within this clade. Ontogenetic data from zebrafish show that substantial premaxillary protrusion is not seen until these fish have undergone metamorphosis at which point the adductor mandibulae musculature becomes divided and all ligamentous attachments become established. A comparative study of families within Cypriniformes shows diverse morphologies of the kinethmoid. The morphological diversification that characterizes the kinethmoid suggests that this feeding structure has played a role in trophic radiations within Cypriniformes, since the morphology of this feature is correlated with feeding habits.     

Taxonomic classification of the reef coral family Mussidae (Cnidaria: Anthozoa: Scleractinia)

Molecular analyses are transforming our understanding of the evolution of scleractinian corals and conflict with traditional classification, which is based on skeletal morphology. A new classification system, which integrates molecular and morphological data, is essential for documenting patterns of biodiversity and establishing priorities for marine conservation, as well as providing the morphological characters needed for linking present‐day corals with fossil species. The present monograph is the first in a series whose goal is to develop such an integrated system. It addresses the taxonomic relationships of 55 Recent zooxanthellate genera (one new) in seven families (one new), which were previously assigned to the suborder Faviina (eight genera are transferred to incertae sedis). The present monograph has two objectives. First, we introduce the higher‐level classification system for the 46 genera whose relationships are clear. Second, we formally revise the taxonomy of those corals belonging to the newly discovered family‐level clade (restricted today to the western Atlantic and Caribbean regions); this revised family Mussidae consists of ten genera (one of which is new) and 26 species that were previously assigned to the ‘traditional’ families Faviidae and Mussidae. To guide in discovering morphologic characters diagnostic of higher‐level taxa, we mapped a total of 38 morphologic characters [19 macromorphology, eight micromorphology, 11 microstructure] onto a molecular tree consisting of 67 species [22 Indo‐Pacific and seven Atlantic species in the traditional family Faviidae; 13 Indo‐Pacific and ten Atlantic species in the traditional family Mussidae; 13 species in the traditional families Merulinidae (5), Pectiniidae (7), and Trachyphylliidae (1); two Atlantic species of traditional Montastraea], and trace character histories using parsimony. To evaluate the overall effectiveness of morphological data in phylogeny reconstruction, we performed morphology‐based phylogenetic analyses using 27 (80 states) of the 38 characters, and compared morphological trees with molecular trees. The results of the ancestral state reconstructions revealed extensive homoplasy in almost all morphological characters. Family‐ and subfamily‐level molecular clades [previously identified as XVII?XXI] are best distinguished on the basis of the shapes of septal teeth and corresponding microstructure. The newly revised family Mussidae (XXI) has septal teeth with regular pointed tips (a symplesiomorphy) and a stout blocky appearance. It has two subfamilies, Mussinae and Faviinae. The subfamily Mussinae is distinguished by spine‐shaped teeth and widely spaced costoseptal clusters of calcification centres. The subfamily Faviinae is distinguished by blocky, pointed tricorne or paddle‐shaped teeth with elliptical bases, transverse structures such as carinae that cross the septal plane, and well‐developed aligned granules. Defining diagnostic characters for the broader data set is more challenging. In analyses of taxonomic subsets of the data set that were defined by clade, morphological phylogenetic analyses clearly distinguished the families Mussidae (XXI) and Lobophylliidae (XIX), as well as the two subfamilies of Mussidae (Mussinae, Faviinae), with one exception (Homophyllia australis). However, analyses of the entire 67‐species data set distinguished the family Lobophylliidae (XIX), but not the Merulinidae (XVII) and not the newly defined Mussidae (XXI), although the subfamily Mussinae was recovered as monophyletic. Some lower‐level relationships within the Merulinidae (XVII) agree with molecular results, but this particular family is especially problematic and requires additional molecular and morphological study. Future work including fossils will not only allow estimation of divergence times but also facilitate examination of the relationship between these divergences and changes in the environment and biogeography. Published 2012. This article is a U.S. Government work and is in the public domain in the USA. Zoological Journal of the Linnean Society, 2012, 166 , 465–529.     

A family matter: conclusive resolution of the taxonomic position of the long-fingered bats, miniopterus

The long-fingered bats (Miniopterus sp.) are among the most widely distributed mammals in the world. However, despite recent focus on the systematics of these bats, their taxonomic position has not been resolved. Traditionally, they are considered to be sole members of Miniopterinae, 1 of 5 subfamilies within the largest family of bats, the Vespertilionidae. However, this classification has increasingly been called into question. Miniopterines differ extensively from other vespertilionids in numerous aspects of morphology, embryology, immunology, and, most recently, genetics. Recent molecular studies have proposed that the miniopterines are sufficiently distinct from vespertilionids that Miniopterinae should be elevated to full familial status. However, controversy remains regarding the relationship of the putative family, Miniopteridae to existing Vespertilionidae and to the closely related free-tailed bats, the Molossidae. We report here the first conclusive analysis of the taxonomic position of Miniopterus relative to all other bat families. We generated one of the largest chiropteran data sets to date, incorporating approximately 11 kb of sequence data from 16 nuclear genes, from representatives of all bat families and 2 Miniopterus species. Our data confirm the distinctiveness of Miniopterus, and we support previous recommendations to elevate these bats to full familial status. We estimate that they diverged from all other bat species approximately 49-38 MYA, which is comparable to most other bat families. Furthermore, we find very strong support from all phylogenetic methods for a sister group relationship between Miniopteridae and Vespertilionidae. The Molossidae diverged from these lineages approximately 54-43 MYA and form a sister group to the Miniopteridae-Vespertilionidae clade.     

Evolution of feeding mechanisms in the family Deinotheriidae (Mammalia: Proboscidea)

The fossil record of the extinct family Deinotheriidae is restricted to Neogene and early Quaternary faunas of the Old World. The family is assigned to the Order Proboscidae but the nature of its relationship to other proboscidean families is still uncertain. Deinotheres are rendered unique by the retention of a single pair of lower tusks and by the morphology of the cheekteeth.
The earliest recorded deinotheres exhibiteo morphological adaptations for a proboscis. In terms of length and prehensibility, the proboscises of the early deinotheres were more tapir-like than elephantine. Later representatives had larger and more powerful but not necessarily longer proboscises.
It is unlikely that the tusks were used for digging and the most probable functions were for stripping vegetation, for providing a source of purchase for the proboscis, and in providing a means of recognition of the individual.
The cheek teeth were deployed in two distinct functional batteries: an anterior crushing battery and a posterior shearing battery. The anterior molar acted initially as part of the shearing battery but, on becoming worn, subscribed to the crushing function of the anterior battery.
Deinotheres were "shearing browsers" and replaced barytheres in the African Paleogene faunas. Evolutionary trends in the known representatives afford some indication of the nature of pre-Miocene adaptations.     

Mechanisms of the jaws of some atheriniform fish

The Atheriniformes is an order of teleost fish which consists of the Atherinoidei (sand smelts etc.), Cyprinodontoidei (tooth-carps) and Exocoetoidei (halfbeaks etc.). Some of its members have protrusible upper jaws and some do not. Photographs have been taken of two species of Cyprinodontoidei feeding, to discover how they use their jaws, which are protrusible. The anatomy and mechanisms of the jaws of these and of various other Atheriniformes have been studied. The terminology of the kinematics of machines is used in a general discussion of the mechanisms of teleost jaws. Anatomical similarities between the jaws of Acanthopterygii, Cyprinoidei and Atheriniformes are noted and discussed.     

Repeatability of clades as a criterion of reliability: a case study for molecular phylogeny of Acanthomorpha (Teleostei) with larger number of taxa

Although much progress has been made recently in teleostean phylogeny, relationships among the main lineages of the higher teleosts (Acanthomorpha), containing more than 60% of all fish species, remain poorly defined. This study represents the most extensive taxonomic sampling effort to date to collect new molecular characters for phylogenetic analysis of acanthomorph fishes. We compiled and analyzed three independent data sets, including: (i) mitochondrial ribosomal fragments from 12S and 16s (814bp for 97 taxa); (ii) nuclear ribosomal 28S sequences (847bp for 74 taxa); and (iii) a nuclear protein-coding gene, rhodopsin (759bp for 86 taxa). Detailed analyses were conducted on each data set separately and the principle of taxonomic congruence without consensus trees was used to assess confidence in the results as follows. Repeatability of clades from separate analyses was considered the primary criterion to establish reliability, rather than bootstrap proportions from a single combined (total evidence) data matrix. The new and reliable clades emerging from this study of the acanthomorph radiation were: Gadiformes (cods) with Zeioids (dories); Beloniformes (needlefishes) with Atheriniformes (silversides); blenioids (blennies) with Gobiesocoidei (clingfishes); Channoidei (snakeheads) with Anabantoidei (climbing gouramies); Mastacembeloidei (spiny eels) with Synbranchioidei (swamp-eels); the last two pairs of taxa grouping together, Syngnathoidei (aulostomids, macroramphosids) with Dactylopteridae (flying gurnards); Scombroidei (mackerels) plus Stromatoidei plus Chiasmodontidae; Ammodytidae (sand lances) with Cheimarrhichthyidae (torrentfish); Zoarcoidei (eelpouts) with Cottoidei; Percidae (perches) with Notothenioidei (Antarctic fishes); and a clade grouping Carangidae (jacks), Echeneidae (remoras), Sphyraenidae (barracudas), Menidae (moonfish), Polynemidae (threadfins), Centropomidae (snooks), and Pleuronectiformes (flatfishes).     

The physical–chemical habitat of the Buenos Aires pejerrey, <Emphasis Type="Italic">Odontesthes bonariensis</Emphasis> (Teleostei,Atherinopsidae), with a proposal of a water quality index

The pejerrey, Odontesthes bonariensis (Valenciennes 1835) (Atheriniformes, Atherinopsidae) is a highly valued food and sport fish both in Argentina and abroad, and has been introduced in numerous natural and manmade environments in this country, Chile, Japan, and Italy. Considering a wide array of environments, where the pejerrey lives and somewhere it does not, we demonstrate its considerable eurytopy and define its range as water traits and chemical composition concern. Moreover, as pejerrey’s natural habitat, the pampasic lagunas (lakes of third-order) in temperate Argentina display a wider range of chemistry traits than many other environments throughout the country, we confirm its adaptability, suggested by previous introduction success. Relative influence of total conductivity and particular ions is evaluated, as well as the relationship of water traits with the fish distribution. A water quality index is provided, which allows the determination of the best conditions for pejerrey cultivation in both artificial and natural conditions. The index summarizes many traits of the realized niche of the fish.     

The RAG-1 exon in the avian order Caprimulgiformes: phylogeny, heterozygosity, and base composition

We sequenced 2.8 kb of the RAG-1 exon for most of the extant genera in the avian order Caprimulgiformes to investigate monophyly of the order and phylogeny within the traditional families. The order is not monophyletic: the Aegothelidae (owlet-nightjars) were the sister group of the Apodiformes (swifts and hummingbirds). There was no support for the monophyly of a clade containing the remaining families of Caprimulgiformes. However, the RAG-1 data strongly supported a relationship between the Podargidae (frogmouths) and Caprimulgidae (nightjars). Within the Caprimulgidae, the Australasian genus Eurostopodus was sister to the rest of the family, which in turn was composed of four major clades, three of which were restricted to the New World and primarily to the Neotropics. The Old World caprimulgids form a monophyletic clade embedded within the New World taxa; consequently, most Old World nightjars are probably the result of a single expansion out of the Neotropics. The genus Caprimulgus was not found to be monophyletic. Several species in the Caprimulgidae have both elevated heterozygosity and high GC3 content; it is likely that these are causally related.