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Invasions of freshwater habitats by marine fishes provide exceptional cases of habitat-driven biological diversification. Freshwater habitats make up less than 1% of aquatic habitats but contain ∼50% of fish species. However, while the dominant group of freshwater fishes (Otophysi) is older than that of most marine fishes (Percomorphaceae), it is less morphologically diverse. Classically, scientists have invoked differences in the tempo and/or mode of evolution to explain such cases of unequal morphological diversification. We tested for evidence of these phenomena in the superfamily Cottoidea (sculpins), which contains substantial radiations of marine and freshwater fishes. We find that the morphology of freshwater sculpins evolves faster but under higher constraint than that of marine sculpins, causing widespread convergence in freshwater sculpins and more morphological disparity in marine sculpins. The endemic freshwater sculpins of Lake Baikal, Siberia, are exceptions that demonstrate elevated novelty akin to that of marine sculpins. Several tantalizing factors may explain these findings, such as differences in habitat stability and/or habitat connectivity between marine and freshwater systems. [ABSTRACT FROM AUTHOR]

The impressive †Oncorhynchus rastrosus of the Pacific Northwest's Miocene and Pliocene eras was the largest salmonid ever to live. It sported a hypertrophied premaxilla with a pair of enlarged teeth which the original describers reconstructed as projecting ventrally into the mouth, leading them to assign the species to "Smilodonichthys," a genus now in synonymy. Through CT reconstruction of the holotype and newly collected specimens, we demonstrate that the famed teeth projected laterally like tusks, not ventrally like sabers or fangs. We also expand the original description to characterize sexual dimorphism in mature, breeding individuals. Male and female †Oncorhynchus rastrosus differ in the form of the vomer, rostro-dermethmoid-supraethmoid, and dentary, much as do other extant species of Oncorhynchus. Male specimens possess a more elongate vomer than do females, and female vomers have concave ventral surfaces and prominent median dorsal keels. The dentary of females has no evidence of a kype, though some specimens of †O. rastrosus have a non-uniform density mesial to the tooth bed, which we interpret as a male kype. Unlike extant Oncorhynchus, male and female †O. rastrosus do not differ in premaxilla shape. Because male and females possess hypertrophied premaxillae and lateral premaxillary spikes, the former common name "Sabertoothed Salmon" no longer reflects our understanding of the species' morphology. Accordingly, we redub †O. rastrosus the Spike-Toothed Salmon and postulate that its spikes were multifunctional, serving as defense against predators, in agonism against conspecifics, and as a practical aid to nest construction. [ABSTRACT FROM AUTHOR]

Abstract--The diverse predatory rockfishes (Sebastes spp.) support extensive commercial fisheries in the northeastern Pacific. Although 106 species of Sebastes are considered valid, many of the ecological, geographical, and morphological boundaries [...]

From dissuading predators to gaining an edge on intraspecific rivals, animals have evolved weapons to meet various needs. Those with the most extreme weapons often use them to battle conspecifics, but some weapons defend against predation and others signal prowess to prospective mates and rivals. Many fishes have evolved armaments, but humans rarely observe these structures in action due to the inaccessibility of many weapon-bearing fish species. For example, how sculpins use the diverse horn-like spines that project from their head remains a mystery. We deduced the function of the weaponized preopercle in the 16 species of sculpins in the subfamily Oligocottinae by determining whether they exhibit three well-documented hallmarks of offensive weapons in terrestrial animals: ontogenetic change, sexual dimorphism, and fluctuating asymmetry. Geometric morphometrics of micro-computed tomography (lCT) scans show no sexual dimorphism in preopercular spine shape but reveal phylogenetically widespread ontogenetic shape change. Fluctuating asymmetry is low to moderate across species. Taken together, these results suggest that despite their varied reproductive habits, frequent territoriality, and possession of weapons that resemble bovid horns, oligocottine sculpins evolved their spines primarily to defend against predators. [ABSTRACT FROM AUTHOR]

Evolutionary biology has long striven to understand why some lineages diversify exceptionally while others do not. Most studies have focused on how extrinsic factors can promote differences in diversification dynamics, but a clade's intrinsic modularity and integration can also catalyze or restrict its evolution. Here, we integrate geometric morphometrics, phylogenetic comparative methods and visualizations of covariance to infer the presence of distinct modules in the body plan of Characiformes, an ecomorphologically diverse fish radiation. Strong covariances reveal a cranial module, and more subtle patterns support a statistically significant subdivision of the postcranium into anterior (precaudal) and posterior (caudal) modules. We uncover substantial covariation among cranial and postcranial landmarks, indicating body-wide evolutionary integration as lineages transition between compressiform and fusiform body shapes. A novel method of matrix subdivision reveals that within- and among-module covariation contributes substantially to the overall eigenstructure of characiform morphospace, and that both phenomena led to biologically important divergence among characiform lineages. Functional integration between the cranium and post-cranial skeleton appears to have allowed lineages to optimize the aspect ratio of their bodies for locomotion, while the capacity for independent change in the head, body and tail likely eased adaptation to diverse dietary and hydrological regimes. These results reinforce a growing consensus that modularity and integration synergize to promote diversification. [ABSTRACT FROM AUTHOR]

Several hundred catfish species (order: Siluriformes) belonging to 11 families inhabit Africa, of which at least six families are endemic to the continent. Although four of those families are well‐known to belong to the 'Big‐Africa clade', no previous study has addressed the phylogenetic placement of the endemic African catfish family Austroglanididae in a comprehensive framework with molecular data. Furthermore, interrelationships within the 'Big‐Africa clade', including the most diverse family Mochokidae, remain unclear. This study was therefore designed to help reconstruct inter‐ and intrarelationships of all currently valid mochokid genera, to infer their position within the 'Big Africa clade' and to establish a first molecular phylogenetic hypothesis of the relationships of the enigmatic Austroglanididae within the Siluriformes. We assembled a comprehensive mitogenomic dataset comprising all protein coding genes and representing almost all recognized catfish families (N = 33 of 39) with carefully selected species (N = 239). We recovered the monophyly of the previously identified multifamily clades 'Big Asia' and 'Big Africa' and determined Austroglanididae to be closely related to Pangasiidae, Ictaluroidea and Ariidae. Mochokidae was recovered as the sister group to a clade encompassing Auchenoglanididae, Claroteidae, Malapteruridae and the African Schilbeidae, albeit with low statistical support. The two mochokid subfamilies Mochokinae and Chiloglanidinae as well as the chiloglanid tribe Atopochilini were recovered as reciprocally monophyletic. The genus Acanthocleithron forms the sister group of all remaining Mochokinae, although with low support. The genus Atopodontus is the sister group of all remaining Atopochilini. In contrast to morphological reconstructions, the monophyly of the genus Chiloglanis was strongly supported in our analysis, with Chiloglanis macropterus nested within a Chiloglanis sublineage encompassing only other taxa from the Congo drainage. This is an important result because the phylogenetic relationships of C. macropterus have been controversial in the past, and because we and other researchers assumed that this species would be resolved as sister to most or all other members of Chiloglanis. The apparent paraphyly of Synodontis with respect to Microsynodontis provided an additional surprise, with Synodontis punu turning out to be the sister group of the latter genus. [ABSTRACT FROM AUTHOR]

Geographically, widespread Neotropical fish lineages offer opportunities to reconstruct historical biogeography patterns and infer processes leading to modern ichthyological diversity and distribution. The characiform family Prochilodontidae is well suited for such reconstruction because their migrations limit population substructure within river systems. Therefore, their biogeographic history should match closely the history of connectivity among Neotropical river basins. Here, we combine a time‐calibrated phylogeny with biogeographic model testing to recover the history of this family's diversification. Results support the Miocene rise of the Andean Eastern Cordillera as a dispersal barrier, but also indicate a much earlier Eocene origin of the trans‐Andean genus Ichthyoelephas. Despite the early origin of the family and its three constituent genera, most prochilodontid lineages originated during the Miocene in Greater Amazonia, likely due to drainage reorganizations caused by Andean uplift. Subsequent speciation appears linked to interbasin exchanges and expansions of Amazonian lineages into Brazilian coastal systems. The modern richness of Prochilodus in easterly drainages appears to be relatively young, with only Prochilodus vimboides likely reaching that region prior to the late Miocene. The rise of the Vaupes Arch coincides with two splits between Orinocoan and Amazonian lineages circa 9 million years ago (Ma). However, two instances of later dispersal between these drainages reveal the permeability of the Vaupes Arch, suggesting that it may promote periodic speciation. This study illustrates how model‐based biogeographic studies of widespread groups can reconstruct historic paths of dispersal and help reveal how landscape evolution promoted modern diversity patterns. [ABSTRACT FROM AUTHOR]

The nearly 150 species of Anostomidae comprise one of the most diverse and taxonomically dynamic families of Neotropical freshwater fishes. A recent revision of the enigmatic and poorly diagnosed genus Anostomoides demonstrated that it contains two valid species, each with complicated taxonomic histories; however, that study did not address their phylogenetic placement. Herein, we integrate molecular and morphological data to demonstrate their distant evolutionary relationship, and thus the polyphyly of Anostomoides. While we reconstruct one of the species in a previously hypothesized placement within a clade also containing Laemolyta , Rhytiodus and Schizodon , the other represents a morphologically and genetically distinctive lineage that diverged early in the history of the family. We describe and illustrate the osteology of this remarkable species, discuss the evolutionary implications of its unique suite of features, and use those characteristics to diagnose a new genus that evolved independently of all other known members of the family for approximately 37 Myr. [ABSTRACT FROM AUTHOR]

The Neotropics harbor the most species-rich freshwater fish fauna on the planet, but the timing of that exceptional diversification remains unclear. Did the Neotropics accumulate species steadily throughout their long history, or attain their remarkable diversity recently? Biologists have long debated the relative support for these museum and cradle hypotheses, but few phylogenies of megadiverse tropical clades have included sufficient taxa to distinguish between them. We used 1288 ultraconserved element loci spanning 293 species, 211 genera, and 21 families of characoid fishes to reconstruct a new, fossil-calibrated phylogeny and infer the most likely diversification scenario for a clade that includes a third of Neotropical fish diversity. This phylogeny implies paraphyly of the traditional delimitation of Characiformes because it resolves the largely Neotropical Characoidei as the sister lineage of Siluriformes (catfishes), rather than the African Citharinodei. Time-calibrated phylogenies indicate an ancient origin of major characoid lineages and reveal a much more recent emergence of most characoid species. Diversification rate analyses infer increased speciation and decreased extinction rates during the Oligocene at around 30 Ma during a period of mega-wetland formation in the proto-Orinoco-Amazonas. Three species-rich and ecomorphologically diverse lineages (Anostomidae, Serrasalmidae, and Characidae) that originated more than 60 Ma in the Paleocene experienced particularly notable bursts of Oligocene diversification and now account collectively for 68% of the approximately 2150 species of Characoidei. In addition to paleogeographic changes, we discuss potential accelerants of diversification in these three lineages. While the Neotropics accumulated a museum of ecomorphologically diverse characoid lineages long ago, this geologically dynamic region also cradled a much more recent birth of remarkable species-level diversity. [Biodiversity; Characiformes; macroevolution; Neotropics; phylogenomics; ultraconserved elements.] [ABSTRACT FROM AUTHOR]

For generations, organismal biologists have learned their craft in hands-on laboratories that teach anatomy, evolution, natural history, systematics, and functional morphology through specimen collection, observation, comparison, and manipulation. Though these activities teach the comparative method that lies at the heart of our discipline, students without access to specimen collections have been excluded from this foundational experience. To fill that gap, we developed a virtual collection of photographs and 3D specimen models and designed entirely online versions of courses in ichthyology and systematics of fishes. The virtualization allows students to illustrate and compare specimens in online labs, identify species from different habitats using dichotomous keys, contextualize the relationships of species, recognize synapomorphies using a phylogeny, take online specimen-based practical exams, and help each other recognize adaptations and diagnostic features on threaded discussion boards. The classes built around the collection educate and provide university credit to students lacking access to similar courses, and their infrastructure allowed face-to-face instruction to shift online rapidly after 2020's novel coronavirus shut down our brick-and-mortar campus. While we may never be able to replicate the aroma of oil-laden alcohol online, specimen virtualization opens access to experiential learning to an underserved and widespread audience; allows new generations of students to develop crucial skills in observation, comparison, and inference; and affords substantial instructional resiliency when unexpected challenges arise. [ABSTRACT FROM AUTHOR]

This study investigated the range‐wide phylogenetics and biogeography of the Cape kurper Sandelia capensis, a primary freshwater fish endemic to and widespread within the Cape Floristic Region (CFR) of South Africa. Maximum likelihood, Bayesian phylogenetic and haplotype network analyses, based on two mitochondrial and two nuclear genes, revealed the existence of three reciprocally monophyletic, deeply divergent and allopatric clades that probably represent cryptic species. The West Coast Clade is largely confined to the Langvlei, Verlorenvlei, Berg and Diep Rivers, the Klein River Clade is endemic to the Klein River and the South Coast Clade is found everywhere else in the range of S. capensis sensu lato. It was hypothesised that divergences within S. capensis sensu lato probably occurred because of isolation of coastal drainages by persistent drainage divides or vicariance of current tributaries by the drowning of their confluences by high sea levels. The current distribution of lineages could be due to historical range expansion and gene flow via river capture or some other mode of transdivide dispersal or dispersal during periods of low sea level via palaeoriver confluences of currently isolated coastal rivers. Comparison of BEAST2 estimated divergence times with the timing of climatic, geological and geomorphological events supported long‐term coastal drainage isolation, punctuated by rare transdivide dispersal events and limited palaeoriver dispersal, as the best explanation of current phylogeographic and divergence patterns in S. capensis. Hydrological barriers that block upstream passage in palaeotributaries could hypothetically explain why S. capensis failed to disperse through certain palaeoriver confluences. There were several sites where biogeographic patterns have likely been confounded by human translocation of S. capensis. Alien fish predators and water extraction may threaten the three cryptic species more severely than previously realised, due to their smaller population sizes and inhabitation of only a portion of the range previously ascribed to S. capensis sensu lato. The preponderance of cryptic diversity and endemism in the CFR suggests that additional undescribed cryptic species of obligate freshwater fishes may be found in short coastal river systems around the world, especially in regions with a history of geological stability and a narrow continental shelf. [ABSTRACT FROM AUTHOR]

The geographic occurrence of moggel Labeo umbratus × mud fish Labeo capensis hybrids and the threat of hybridisation to the genetic integrity of L. umbratus were investigated. Genetic evidence from mtDNA cytb and nDNA s7 intron sequence data indicated probable interspecific hybridisation in two impoundments, Hardap Dam (Orange River Basin, Namibia) and Darlington Dam (Sundays River Basin, Eastern Cape, South Africa). Some putative hybrids were morphologically identifiable on account of their meristic and morphometric intermediacy to the parent species. Human activities appear to drive the observed hybridisation, either through dam construction and direct stocking of L. umbratus or via translocation of Labeo capensis and the previously isolated Orange River lineage of L. umbratus into the southern‐flowing systems by inter‐basin water transfers. It is recommended that further translocation of fish from these areas should be avoided. [ABSTRACT FROM AUTHOR]

We present and describe a new species of Enteromius, adding to the 16 species of Enteromius currently recorded from Gabon, West Africa. This new species is distinguished from all other Gabonese Enteromius by the presence of several distinct spots on the dorsal fin in combination with three or four round spots on the flanks. In Africa, it is superficially similar to Enteromius walkeri and with which it shares an unusual allometry in that the proportional length of the barbels decreases as the fish grows. Nevertheless, one can distinguish these species by vertebral number, maximum standard length, the length of the anterior barbels, the length of the caudal peduncle and in most specimens, the number of lateral‐line and circumpeduncular scales. These two species also inhabit widely separated drainages, with E. walkeri occurring in coastal drainages of Ghana including the Pra and Ankobra Rivers and the new species occurring in tributaries of the Louetsi and Bibaka Rivers of Gabon, which are part of the Ogowe and Nyanga drainages, respectively. Despite extensive collections in those drainages the new species is known from only two localities, suggesting the importance of conservation of its known habitat. [ABSTRACT FROM AUTHOR]

Curimatidae, the fourth largest family of detritivorous Neotropical characiform fishes, encompasses eight extant genera and over 110 species dwelling in diverse freshwater habitats from Costa Rica to Argentina. Extensive phylogenetic analyses of soft anatomy and osteology provided evidence for intergeneric and most interspecific relationships, and formed the basis of curimatid taxonomy for nearly 40 years. However, that morphological phylogeny demonstrated incomplete phylogenetic resolution at various scales and has never been tested with extensive molecular data. Herein, we infer molecular phylogenies spanning ∼70% of the known species diversity using three nuclear and three mitochondrial loci. Topologies from concatenated likelihood and Bayesian analyses and coalescent Bayesian species trees agree broadly with each other, and with the prior morphological hypothesis in many, but not all respects. All molecular analyses support the monophyly of Curimatidae and of six of its constituent genera, and agree on the placement of Curimatopsis as sister to all other curimatids. DNA-based intergeneric relationships differ substantially from prior morphological hypotheses by placing Curimata sister to Potamorhina and Psectrogaster sister to Pseudocurimata , rather than in a ladderized arrangement. Our results also resolve a major uncertainty in the morphological tree by revealing Cyphocharax , a genus for which no anatomical synapomorphy has ever been proposed, as a paraphyletic assemblage containing a monophyletic Steindachnerina and a polyphyletic Curimatella . Overall, the phylogeny expands substantially our understanding of the morphology, phylogenetics and evolution of the Curimatidae, and will guide future intrageneric studies by improving precision in the choice of comparative taxa. [ABSTRACT FROM AUTHOR]

Studies on the diversity, taxonomy, phylogeny, and biogeography of Neotropical Fishes have thrived over the twenty years that have elapsed since the first symposium on their phylogeny and classification in Porto Alegre, Brazil. Here, we review recent advances in the study of Neotropical fishes and assess the known diversity of freshwater species in that region. 6,255 valid freshwater species have been discovered in the Neotropics so far, and we estimate that over 9,000 species will be known when the inventory is complete. We also summarize the events of the second Symposium on Phylogeny and Classification of Neotropical Fishes that took place last year in Londrina, Brazil. Along with invited talks on the biodiversity of all major groups of Neotropical fishes, a series of presentations on the development of fish collections, and numerous contributed talks, the meeting included a special session to honor Dr. Richard Vari, who was one of the most prolific and beloved members of our community. [ABSTRACT FROM AUTHOR]

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Migratory detritivores of the characiform family Prochilodontidae occur throughout the freshwaters of much of South America. Prochilodontids often form massive populations and many species achieve substantial body sizes; a combination that makes them one of the most commercially important fish groups on the continent. Their economic significance notwithstanding, prochilodontids have never been the subject of a comprehensive molecular phylogenetic analysis. Using three mitochondrial and three nuclear loci spanning all prochilodontid species, we generated a novel phylogenetic hypothesis for the family. Our results strongly support monophyly of the family and the three included genera. A novel, highly supported placement of Ichthyoelephas sister to the clade containing Prochilodus and Semaprochilodus diverges from a previous morphological hypothesis. Most previously hypothesized interspecific relationships are corroborated and some longstanding polytomies within Prochilodus and Semaprochilodus are resolved. The morphologically similar P. brevis , P. lacustris , P. nigricans and P. rubrotaeniatus are embedded within what is herein designated as the P. nigricans group. Species limits and distributions of these species are problematic and the group clearly merits taxonomic revision. [ABSTRACT FROM AUTHOR]

Although 11 studies have addressed the systematics of the four families and 281 fish species of the ecomorphologically diverse Anostomoidea, none has proposed a global hypothesis of relationships. We synthesized these studies to yield a supermatrix with 463 morphological characters among 174 ingroup species, and inferred phylogeny with parsimony and Bayesian optimization. We evaluated the applicability of the supermatrix approach to morphological datasets, tested its sensitivity to missing data, determined the impact of homoplastic characters on phylogenetic resolution, and determined the distribution of homologies and homoplasies on the topology. Despite more than 60% missing data, analyses supported the monophyly of all families, and phylogenetic structure degraded only with inclusion of species with high percentages of missing data and in analyses limited to homoplasies. The latter differs modestly from the full matrix indicating phylogenetic signal in homoplastic characters. Character distributions differ across the phylogeny, with a greater prevalence of homologies at deeper nodes and homoplasies nearer the tips than expected by chance. This may suggest early diversification into distinct bauplans with subsequent diversification of faster evolving character systems. The morphological supermatrix approach is powerful and allows integration of classical data with modern methods to examine the evolution of multiple character systems. [ABSTRACT FROM AUTHOR]

Highlights: [•] Speckled dace occur throughout the western US and have high genetic and morphological variation, called a species complex. [•] Three clades warrant species-level status: Malheur stream dace, Stinking Lake Spring dace, and other sampled dace. [•] Foskett Spring dace are not monophyletic, but substantial population structure separates Foskett Spring from other dace. [•] We recommend ESU status for the isolated population of speckled dace in Foskett Spring. [•] High taxonomic diversity within this region indicates a need for a range-wide phylogeographic study of speckled dace. [Copyright &y& Elsevier]

Highlights: [•] The first molecular phylogeny of Chilodontidae based on all recognized species. [•] Chilodontidae is monophyletic as well as its two genera, Caenotropus and Chilodus. [•] Chilodus punctatus is paraphyletic with C. fritillus and C. zunevei nested within it. [•] We discuss apparent morphological convergences and the possibility of cryptic species. [Copyright &y& Elsevier]

Fifty-six species or approximately 20% of the Neotropical characiform superfamily Anostomoidea (families Anostomidae, Chilodontidae, Curimatidae and Prochilodontidae) occur in the freshwaters of French Guiana, Guyana, and Suriname although these regions span only approximately 6% of the native range of this morphologically and ecologically diverse superfamily. As a result of the high diversity of anostomoids in the Guianas, the taxonomic and/or geographic boundaries of many species are poorly understood, particularly within the family Anostomidae. This contribution unites results of prior taxonomic revisions with surveys of the holdings of the superfamily in seven major natural history collections to provide distribution maps and keys to the identification of all anostomoid species known to occur in the Guianas. These maps reveal six major areas of endemism: the Takutu and Ireng rivers (Rio Branco drainage, Amazon basin), the Barima and Waini rivers (Orinoco drainage), the Essequibo-Rupununi River system (including the Demerara and Berbice rivers), a union of the Corantijn, Nickerie, Coppename, Saramacca and Suriname river drainages, the Marowijne/Maroni River system (including the Litani and Mana rivers), and the Oyapock-Approuague River basins. Of these, the Essequibo- Rupununi system harbours the most exceptionally diverse assemblage of anostomoid species, likely as a result of faunal exchange between the Rio Branco and Essequibo River across the Rupununi portal. [ABSTRACT FROM AUTHOR]

Cyphocharax biocellatus, a species of curimatid characiform apparently endemic to the Marowijne River/ Fleuve Maroni system in Suriname and French Guiana, and the Mana River basin in French Guiana is described as new. The new species is diagnosed from congeners based on meristic and morphometric features and details of pigmentation of the body and dorsal and caudal fins. The description of the new species brings the total number of Cyphocharax species in the drainages overlying the Guiana Shield to 14, with eight species occurring in the northern-flowing river systems of the Guianas. As such, the Guianas demonstrate the highest species-level diversity within Cyphocharax among comparablysized areas within the range of the genus. The pronounced diversity of the genus Cyphocharax and the family Curimatidae at the level of the Maroni basin, the Guianas and the rivers systems draining the Guiana Shield is discussed. [ABSTRACT FROM AUTHOR]

To achieve maximum efficacy, taxonomic studies that seek to distinguish amongst species must first account for allometric shape variation within species. Two recently developed software packages (SMATR and MorphoJ) offer regression-based allometric approaches that are notable for their statistical power and ease of use and that may prove highly useful to taxonomists working with linear or geometric morphometric data. We investigate species delimitation of the slender-bodied fishes in the Leporinus cylindriformis group using these programs and demonstrate the utility of the allometric corrections that they provide. Without allometric correction, many pairs of species are difficult to distinguish on the basis of morphometrics, but once regressions are used to account for marked allometric variation within species, most of the recognized species in this group can be readily distinguished with linear or geometric morphometrics, particularly using variation in the depth of the body. Both approaches returned congruent patterns of separation amongst putative species, but the geometric approach in MorphoJ distinguished amongst four more pairs of species than did the linear approach in SMATR and appears to provide slightly more statistical power. Based on distinctive morphometrics, meristics, and coloration, a highly elongate species of Leporinus from the Suriname, Corantijn, and Coppename rivers of Suriname is described herein as a new species, The unique L. cylindriformis holotype from Porto de Moz, Brazil differs in morphology, meristics, and pigmentation from specimens commonly referred to that species from the main basin of the Amazon; the latter specimens may represent an additional undescribed species. The L. cylindriformis holotype itself may represent a rare species or a specimen collected at the edge of its native range. Measurements of the holotype and paratype of Leporinus niceforoi, which were collected in the Amazonian slope of Colombia, differ substantially from similarly pigmented and putatively conspecific specimens from Amazonian portions of Ecuador and Peru. Recently collected specimens from Colombia are needed to determine whether the observed morphometric variation encompassed by the current concept of L. niceforoi indicates a morphocline within a single species, suggests the presence of multiple cryptic species, or results from shrinkage of the types. In all these cases, linear or geometric morphometric data can reliably differentiate amongst species, but only after one accounts for allometric shape variation. The new SMATR and MorphoJ software packages both offer easy and effective approaches to such allometrically informed taxonomy, and may prove useful to any systematist working on taxa that change shape as they grow. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, , 103-130. [ABSTRACT FROM AUTHOR]

Analysis of a morphological dataset containing 152 parsimony-informative characters yielded the first phylogenetic reconstruction spanning the South American characiform family Anostomidae. The reconstruction included 46 ingroup species representing all anostomid genera and subgenera. Outgroup comparisons included members of the sister group to the Anostomidae (the Chilodontidae) as well as members of the families Curimatidae, Characidae, Citharinidae, Distichodontidae, Hemiodontidae, Parodontidae and Prochilodontidae. The results supported a clade containing Anostomus, Gnathodolus, Pseudanos, Sartor and Synaptolaemus (the subfamily Anostominae sensu Winterbottom) albeit with a somewhat different set of relationships among the species within these genera. Anostomus as previously recognized was found to be paraphyletic and is split herein into two monophyletic components, a restricted Anostomus and the new genus Petulanos gen. nov., described herein. Laemolyta appeared as sister to the clade containing Anostomus, Gnathodolus, Petulanos, Pseudanos, Sartor and Synaptolaemus. Rhytiodus and Schizodon together formed a well-supported clade that was, in turn, sister to the clade containing Anostomus, Gnathodolus, Laemolyta, Petulanos, Pseudanos, Sartor and Synaptolaemus. Anostomoides was sister to the clade formed by these nine genera. Leporinus as currently defined was not found to be monophyletic, although certain clades within that genus were supported, including the species with subterminal mouths in the former subgenus Hypomasticus which we recognize herein as a genus. Abramites nested in Leporinus, and Leporellus was found to be the most basal anostomid genus. The presence of cis- and trans-Andean species in Abramites, Leporellus, Leporinus and Schizodon, all relatively basal genera, suggests that much of the diversification of anostomid species pre-dates the uplift of the Andean Cordilleras circa 11.8 million years ago. Several important morphological shifts in anostomid evolution are illustrated and discussed, including instances of convergence and reversal. © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society, 2008, 154, 70–210. [ABSTRACT FROM AUTHOR]

Pseudanos winterbottomi n. sp. from the Orinoco drainage of Venezuela and the Tapajós drainage of Brazil resembles Pseudanos gracilis (Kner) in meristic and morphometric characters but differs from it in possession of a single midlateral stripe instead of a series of lateral spots, four branchiostegal rays instead of three, two pores on the sensory canal of the nasal instead of one, four pores on the sensory canal of the first infraorbital arranged in a square instead of three pores arranged in a line or shallow V, a dorsal process on the mesopterygoid that wraps around the posterior of the palatine (vs absence of such a process), the absence of a thin, posteriorly directed process on the ectopterygoid running ventral to the palatine (vs presence of such a process), a thick, blocklike palatine instead of a thinner, platelike palatine, and an almost completely closed metapterygoid/quadrate fenestra (vs an open fenestra). An updated key to the anostomine characiforms of the genera Anostomus, Gnathodolus, Pseudanos, Sartor, and Synaptolaemus is presented. [ABSTRACT FROM AUTHOR]

In theory, evolutionary modularity allows anatomical structures to respond differently to selective regimes, thus promoting morphological diversification. These differences can then influence the rate and direction of phenotypic evolution among structures. Here we use geometric morphometrics and phenotypic matrix statistics to compare rates of craniofacial evolution and estimate evolvability in the face and braincase modules of a clade of teleost fishes (Gymnotiformes) and a clade of mammals (Carnivora), both of which exhibit substantial craniofacial diversity. We find that the face and braincase regions of both clades display different degrees of integration. We find that the face and braincase evolve at similar rates in Gymnotiformes and the reverse in Carnivora with the braincase evolving twice as fast as the face. Estimates of evolvability and constraints in these modules suggest differential responses to selection arising from fluctuations in phylogenetic integration, thus influencing differential rates of skull-shape evolution in these two clades. [ABSTRACT FROM AUTHOR]