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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.

Buser, Thaddaeus J., Kee, Victoria E., Terry, Rebecca C., Summers, Adam P., Sidlauskas, Brian L. (2023): Taurus of the Tidepool? Inferring the Function of Cranial Weapons in Intertidal Sculpins (Pisces: Cottoidea: Oligocottinae). Ichthyology & Herpetology 111 (1): 98-108, DOI: 10.1643/i2022044, URL: http://dx.doi.org/10.1643/i2022044

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.

Made available in DSpace on 2022-04-28T17:21:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-02-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) US-Brazil Fulbright Fellowship Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) 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. Oregon State Univ, Dept Fisheries & Wildlife, 104 Nash Hall, Corvallis, OR 97331 USA Univ Estadual Londrina, Programa Posgrad Ciencias Biol, Ctr Ciencias Biol, Rodovia Celso Garcia Cid,Campus Univ, BR-86057970 Londrina, PR, Brazil Univ Estadual Paulista, Inst Biociencias, Dept Biol Estrutural & Func, R Prof Dr Antonio CW Zanin 250, BR-18618689 Botucatu, SP, Brazil Univ Estadual Paulista, Inst Biociencias, Dept Biol Estrutural & Func, R Prof Dr Antonio CW Zanin 250, BR-18618689 Botucatu, SP, Brazil FAPESP: 16/11313-8 FAPESP: 18/24040-5 CNPq: 404991/2018-1 CNPq: 306054/2006-0 CNPq: 203489/2018-7 CNPq: 302872-2018-3 FAPESP: 18/20610-1 FAPESP: 16/09204-6 FAPESP: 14/26508-3

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.

We assessed the fish diversity of the Ogooué and Sébé rivers in and around the Rapids of Mboungou Badouma and Doumé Ramsar site in Gabon. The ichthyofauna of this region has not been extensively sampled in over 150 years, yet encompasses one the most important type localities for fishes in Central Africa. We sampled a total of 31 sites and collected nearly 3000 fish specimens representing 97 species. Nine species appeared to be new to science, and one catalyzed the recent description of a new genus of mormyrid fishes.

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] Copyright of Ichthyology & Herpetology is the property of American Society of Ichthyologists & Herpetologists and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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.

The characiform fishes of the Neotropics and Africa radiated remarkably in ecomorphology, but the macroevolutionary processes responsible for their biodiversity remain unexplored, and the degree to which their continental diversification parallels classic adaptive radiations remains untested. We reconstruct their diversification using a new fossil-calibrated molecular phylogeny, dietary information, and geometric morphometrics. Though body shape diversified early in a manner consistent with an ancient continental adaptive radiation, trophic shifts did not always coincide with shape changes. With the notable exception of piscivores, lineages that converged in diet did not converge closely in body shape. Shifts in habitat or other variables likely influenced body shape evolution in addition to changes in diet, and the clade's history departs from many classic adaptive radiations in lakes or on islands, in which trophic convergence drives morphological convergence. The contrast between the Neotropical radiation's exhaustive exploration of morphospace and the more restrained diversification in Africa suggests a major role for contingency in characiform evolution, with the presence of cypriniform competitors in the Old World, but not the New, providing one possible explanation. Our results depict the clearest ecomorphological reconstruction to date for Characiformes and set the stage for studies further elucidating the processes underlying its diversification.

Made available in DSpace on 2022-05-01T09:47:22Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-01-01 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.] Department of Structural and Functional Biology Institute of Biosciences São Paulo State University Department of Fisheries Wildlife and Conservation Sciences Oregon State University Department of Ecology and Evolutionary Biology Yale University Sector of Zoology Institute of Biosciences São Paulo State University Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, Valle del Cauca Department of Ichthyology American Museum of Natural History Instituto de Biologiìa Universidad Nacional Autónoma de Mexico School of Biological Sciences Monash University Department of Biological Sciences and Museum of Natural Science Louisiana State University Cornell Lab of Ornithology Cornell University Museum of Vertebrates Department de Biología Facultad de Ciencias Pontificia Universidad Javeriana Faculdade de Filosofia Ciências e Letras Universidade de São Paulo SP Department of Ecology and Evolutionary Biology University of California Department of Structural and Functional Biology Institute of Biosciences São Paulo State University Sector of Zoology Institute of Biosciences São Paulo State University

Made available in DSpace on 2020-12-10T19:54:54Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-03-01 NSF Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Target enrichment of conserved nuclear loci has helped reconstruct evolutionary relationships among a wide variety of species. While there are preexisting bait sets to enrich a few hundred loci across all fishes or a thousand loci from acanthomorph fishes, no bait set exists to enrich large numbers (>1,000 loci) of ultraconserved nuclear loci from ostariophysans, the second largest actinopterygian superorder. In this study, we describe how we designed a bait set to enrich 2,708 ultracon served nuclear loci from ostariophysan fishes by combining an existing genome assembly with low coverage sequence data collected from two ostariophysan lineages. We perform a series of enrichment experiments using this bait set across the ostariophysan tree of life, from the deepest splits among the major groups (> 150 Ma) to more recent divergence events that have occurred during the last 50 million years. Our results demonstrate that the bait set we designed is useful for addressing phylogenetic questions from the origin of crown ostariophysans to more recent divergence events, and our in silico results suggest that this bait set may be useful for addressing evolutionary questions in closely related groups of fishes, like Clupeiformes. Louisiana State Univ, Dept Biol Sci, Baton Rouge, LA 70803 USA Louisiana State Univ, Museum Nat Sci, Baton Rouge, LA 70803 USA Univ Tennessee, Dept Biol Geol & Environm Sci, Chattanooga, TN 37403 USA Oregon State Univ, Dept Fisheries & Wildlife, Corvallis, OR 97331 USA Cornell Univ, Cornell Lab Ornithol, Museum Vertebrates, Ithaca, NY 14850 USA Univ Estadual Paulista, Inst Biociencias, Dept Morfol, BR-18618689 Botucatu, SP, Brazil Univ Louisiana Lafayette, Dept Biol, Lafayette, LA 70503 USA Univ Estadual Paulista, Inst Biociencias, Dept Zool, Botucatu, SP, Brazil Univ Calif Los Angeles, Dept Ecol & Evolutionary Biol, Los Angeles, CA 90095 USA Univ Estadual Paulista, Inst Biociencias, Dept Morfol, BR-18618689 Botucatu, SP, Brazil Univ Estadual Paulista, Inst Biociencias, Dept Zool, Botucatu, SP, Brazil NSF: DEB-1242267 NSF: DEB-1257898 NSF: DEB-1354149 FAPESP: 14/26508-3 FAPESP: 16/11313-8 FAPESP: 14/05051-5 FAPESP: 14/06853-8

The planned construction of 38 hydropower dams will impact the fish species inhabiting freshwater ecosystems in the megadiverse African country of Gabon. Many of Gabon's most culturally and economically important fish species are marine‐associated, moving between fresh and salt or brackish waters. However, we know little about their life histories or movement patterns, which makes it difficult to predict the impacts of dam development on biodiversity and fisheries in Gabon. Here, we apply MaxEnt distribution modeling to predict the distribution of marine‐associated fishes in Gabon's freshwaters. The model predicts a high likelihood of these fishes occurring in every coastal watershed, throughout the undammed Nyanga drainage, and extending ~400 km into the Ogooué River and its tributaries Ngounie and Abanga. If all 38 dams are constructed, marine‐associated fishes will lose approximately 17% of riverine habitats (7400 km) including 7% of the best quality habitat (460 km). Proposed dams pose a substantial threat to Gabon's most culturally and economically important fishes.

Synopsis The decreasing cost of acquiring computed tomographic (CT) data has fueled a global effort to digitize the anatomy of museum specimens. This effort has produced a wealth of open access digital three-dimensional (3D) models of anatomy available to anyone with access to the Internet. The potential applications of these data are broad, ranging from 3D printing for purely educational purposes to the development of highly advanced biomechanical models of anatomical structures. However, while virtually anyone can access these digital data, relatively few have the training to easily derive a desirable product (e.g., a 3D visualization of an anatomical structure) from them. Here, we present a workflow based on free, open source, cross-platform software for processing CT data. We provide step-by-step instructions that start with acquiring CT data from a new reconstruction or an open access repository, and progress through visualizing, measuring, landmarking, and constructing digital 3D models of anatomical structures. We also include instructions for digital dissection, data reduction, and exporting data for use in downstream applications such as 3D printing. Finally, we provide Supplementary Videos and workflows that demonstrate how the workflow facilitates five specific applications: measuring functional traits associated with feeding, digitally isolating anatomical structures, isolating regions of interest using semi-automated segmentation, collecting data with simple visual tools, and reducing file size and converting file type of a 3D model.

Made available in DSpace on 2019-10-04T12:30:54Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-10-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) NSF 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 similar to 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. Univ Estadual Paulista, Inst Biociencias, Dept Morfol, Botucatu, SP, Brazil Smithsonian Inst, Dept Vertebrate Zool, Natl Museum Nat Hist, Washington, DC 20560 USA Oregon State Univ, Dept Fisheries & Wildlife, Corvallis, OR 97331 USA Cornell Univ, Museum Vertebrates, Dept Ecol & Evolutionary Biol, Ithaca, NY USA Univ Estadual Paulista, Inst Biociencias, Dept Morfol, Botucatu, SP, Brazil FAPESP: 2011/08374-1 FAPESP: 2013/16436-2 FAPESP: 2014/26508-3 FAPESP: 2016/11313-8 NSF: DEB-1257898

Data scarcity impedes a comprehensive impact assessment of the 38 dams currently proposed within the highly biodiverse central African nation of Gabon. Here, we present a multiple‐species MaxEnt distribution modeling approach to assess species richness for freshwater fishes at the landscape level and demonstrate its utility in identifying proposed dam sites in Gabon that fall in highly diverse areas. We modeled habitat suitability for 202 of Gabon's fresh and brackish water fish species based on georeferenced presence data from museum specimens and a set of ecologically meaningful environmental conditions. We removed poor performing species from the model and compiled the distributions of 114 well‐performing species to generate a new metric, the species pseudorichness index (pR), defined as the cumulative number of species that are highly suited to the habitat in a given segment of river. We used pR as a proxy for true species richness and use this metric to evaluate the distribution of freshwater fish diversity relative to the proposed dam development in Gabon. We found that more than 80% of the proposed dams in Gabon overlap with areas of high pR, implying that planned hydroelectric development in Gabon may disproportionately affect high diversity areas. These dams deserve more focused baseline assessments and conservation action. This approach provides a rapid way to initiate a landscape‐scale assessment of freshwater fish diversity to inform conservation decisions in areas that are species rich, but data poor.

Made available in DSpace on 2019-10-04T12:33:32Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-12-01 The data presented herein support the article Molecular phylogenetics of the Neotropical fish family Prochilodontidae (Teleostei: Characiformes) (B.F. Melo, B.L. Sidlauskas, B.W. Frable, K. Hoekzema, R.P. Vad, C. Oliveira, 2016) [1], which inferred phylogenetic relationships of the prochilodontids from an alignment of three mitochondrial and three nuclear loci (5279 bp) for all 21 recognized prochilodontid species and 22 related species. Herein, we provide primer sequences, museum voucher information and GenBank accession numbers. Additionally, we more fully describe the maximum-likelihood and Bayesian phylogenetic analyses of the concatenated dataset, detail the Bayesian species tree analysis, and provide the maximum likelihood topologies congruent with prior morphological hypotheses that were compared with the unconstrained tree using Shimodaira-Hasegawa tests. (C) 2016 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/40). Oregon State Univ, Dept Fisheries & Wildlife, Corvallis, OR 97331 USA Univ Calif San Diego, Scripps Inst Oceanog, Marine Vertebrate Collect, La Jolla, CA 92093 USA Univ Estadual Paulista, Inst Biociencias, Dept Morfol, Botucatu, SP, Brazil Smithsonian Inst, Natl Museum Nat Hist, Dept Vertebrate Zool, Washington, DC 20560 USA Univ Estadual Paulista, Inst Biociencias, Dept Morfol, Botucatu, SP, Brazil

International audience; 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.

Since the discovery of spirit-based preservation, scientists have based innumerable studies of systematics, anatomy, development, biogeography, evolutionary biology, and ecomorphology on fluid specimens held by the world's natural history collections. Though alcohol preservation can alter specimen measurements through dehydration and shrinkage, the magnitude of this problem over decadal timescales has never been estimated. If substantial, long-term preservational effects could compromise studies that depend on the comparability of morphometrics drawn from specimens collected at different times unless the artifacts were explicitly controlled. To evaluate the importance of these potential artifacts, we obtained geometric morphometric data from series of four common fish species collected from the Willamette River drainage over the last 70 years and preserved in the Oregon State Ichthyology Collection in 50% isopropanol after formalin fixation. Most regressions of principal component axes against date of col...

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.

This is the publisher’s final pdf. The published article is copyrighted by United States Department of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service and can be found at: http://fisherybulletin.nmfs.noaa.gov/

Members of the Leporinus desmotes species complex can be distinguished from other barred or banded congeners by the combination of nine distinct black bars across the head and trunk and long, pointed, laterally compressed and upward curving symphyseal dentary teeth. A taxonomic reassessment of this complex revealed two new species, one from the Orinoco and Negro rivers of Venezuela and Brazil, and the other from the Xingu and Tapajós rivers of Brazil. Both species are similar to L. desmotes and L. jatuncochi, but differ significantly in body shape morphology, coloration, and/or circumpeduncular scale counts. Genetic evidence also contributes to the recognition of both new species. This contribution also maps the geographic distribution of the four known species, and highlights the presence of an unusual meristic polymorphism within Leporinus desmotes sensu stricto that may suggest the presence of even more unrecognized diversity. RESUMO As espécies do complexo Leporinus desmotes diferem da maioria dos congêneres com base nas nove barras transversais escuras ao redor da cabeça e do corpo, e do dente sinfisiano do dentário alongado, comprimido lateralmente e ligeiramente curvado para cima. Uma revisão taxonômica desse complexo revelou a existência de duas espécies novas, uma dos rios Orinoco e Negro na Venezuela e Brasil, e outra das drenagens dos rios Xingu e Tapajós, no Brasil. As duas espécies novas são similares à L. desmotes e L. jatuncochi, das quais diferem significativamente por uma combinação de forma do corpo, coloração e número de séries de escamas ao redor do pedúnculo caudal. Dados genéticos também corroboram o reconhecimento das duas espécies novas. Esta contribuição ainda traz novos dados sobre a distribuição geográfica de cada uma das espécies do complexo, e discute a presença de um incomum polimorfismo no número de escamas ao redor do pedúnculo caudal em Leporinus desmotes stricto sensu, que sugere a presença de uma diversidade ainda maior de espécies não descritas.

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.

Speckled dace (Rhinichthys osculus) is a small cyprinid that occurs throughout western North America and is the most commonly occurring fish in Oregon. Because of the high genetic and morphological variation in this species across its range, it has been referred to as a species complex; however, no revision to its taxonomy has occurred since 1984. Here, the phylogenetics and population genetics of speckled dace are examined throughout Oregon's Great Basin to describe genetic variation and infer the geographic boundaries between distinct taxonomic entities and populations. We tested the validity of a putative subspecies, Foskett Spring speckled dace, that occurs in a single spring within Warner Valley in Southeast Oregon and is listed Federally as threatened. Dace were collected from Foskett Spring and all surrounding basins containing speckled dace (Warner, Goose Lake, Lake Abert, Silver Lake, and Malheur), as well as Stinking Lake Spring (located within Malheur), created phylogenetic trees from mitochondrial ND2 and nuclear S7 sequence data, and genotyped eight microsatellite loci for population-level analyses. Three highly divergent clades warrant species-level status: Malheur stream dace, Stinking Lake Spring dace, and dace from the other four basins combined. Although Foskett Spring dace were not monophyletic, substantial population structure occurs at the basin-level and separates Foskett Spring dace from other dace in the surrounding Warner Valley. Thus, we recommend ESU status for the isolated population of speckled dace in Foskett Spring. The high, previously unrecognized, taxonomic diversity within this region indicates a need for a range-wide phylogeographic study of speckled dace and an investigation of the morphological distinctiveness of the putative new species.

A new species of Leporinus in the L. cylindriformis group is described from the Rio Orinoco basin, Venezuela. This new species can be separated from congeners by the combination of an extremely dorsoventrally slender body, the presence of a prominent midlateral spot positioned ventral to the dorsal fin, and the absence of any other intense dark pigmentation. The new species is most similar to L. aripuanaensis from the Rio Aripuana, Brazil, but can be most easily differentiated from that species by the absence (79% of specimens) or faint presence (21% of specimens) of a circular dark spot over the hypural plate in the new species, versus the presence of an intensely pigmented dark spot in that position, respectively. It can be further distinguished from L. aripuanaensis by the modal number of predorsal scales (12 versus 11). Small juveniles of the two species do not differ morphometrically, but their allometric growth trajectories differ. Above 70 mm SL, the new species differs from L. aripuanaensis in int...

Chilodontidae is a small family of eight described characiform species popularly known as headstanders. These small to moderately sized fishes are well known to aquarists, who prize their striking spotted pigmentation and unusual behaviors, and to systematists, who have revised both chilodontid genera in recent memory and studied their phylogenetic relationships using a comprehensive morphological dataset. However, no molecular phylogeny for the family has ever been proposed. Here, we reconstruct phylogenetic relationships for all eight known chilodontid species using three mitochondrial and two nuclear loci. Results largely agree with the previous morphological hypothesis, and confirm the monophyly of the family as well as its included genera, Caenotropus and Chilodus. The molecular topology differs slightly from the morphological hypothesis by placing Caenotropus maculosus rather than C. mestomorgmatos as the sister to the remaining three congeners, and by reconstructing the Curimatidae as the closest outgroup family, rather than the Anostomidae. However, the topologies supported by the morphological data were only slightly less likely and could not be rejected via Shimodaira-Hasegawa tests. Within Chilodus, two described species with distinctive pigmentation (C. fritillus and C. zunevei) appear embedded within the broad distributed C. punctatus clade, suggesting the presence of cryptic taxa with polymorphic pigmentation within the present concept of C. punctatus. Future work should combine morphological and molecular data to revisit the taxonomy and systematics of Chilodus and determine species limits within the C. punctatus-group sensu lato.

Made available in DSpace on 2018-11-26T16:48:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-09-01 NSF Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) 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 Glade 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. (C) 2016 Elsevier Inc. All rights reserved. Univ Estadual Paulista, Inst Biociencias, Dept Morfol, R Prof Dr Antonio CW Zanin S-N, BR-18618689 Botucatu, SP, Brazil Smithsonian Inst, Natl Museum Nat Hist, Dept Vertebrate Zool, Washington, DC 20560 USA Oregon State Univ, Dept Fisheries & Wildlife, Corvallis, OR 97331 USA Univ Estadual Paulista, Inst Biociencias, Dept Morfol, R Prof Dr Antonio CW Zanin S-N, BR-18618689 Botucatu, SP, Brazil NSF: DEB-1257898 FAPESP: 11/08374-1 FAPESP: 12/51014-9 FAPESP: 13/16436-2 FAPESP: 14/26508-3 CNPq: 40258/2014-7

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, Leporinus apollo sp. nov. 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, 162, 103–130.

Innovations in locomotor morphology have been invoked as important drivers of vertebrate diversification, although the influence of novel locomotion strategies on marine fish diversification remains largely unexplored. Using triggerfish as a case study, we determine whether the evolution of the distinctive synchronization of enlarged dorsal and anal fins that triggerfish use to swim may have catalyzed the ecological diversification of the group. By adopting a comparative phylogenetic approach to quantify median fin and body shape integration and to assess the tempo of functional and morphological evolution in locomotor traits, we find that: (1) functional and morphological components of the locomotive system exhibit a strong signal of correlated evolution; (2) triggerfish partitioned locomotor morphological and functional spaces early in their history; and (3) there is no strong evidence that a pulse of lineage diversification accompanied the major episode of phenotypic diversification. Together these findings suggest that the acquisition of a distinctive mode of locomotion drove an early radiation of shape and function in triggerfish, but not an early radiation of species.

We examined the shapes and sizes of dermal bones of the palate of selected Palaeozoic tetrapods in order to identify the ancestral states of palatal bone morphologies in the earliest tetrapods, to learn how the composition of the palate varies within and among early tetrapod radiations, and to recognize evolutionary correlations among the size and shapes of skeletal elements in this important group of animals. We find that whereas the palatal bones themselves and their arrangements are usually conserved, considerable correlated evolutionary change occurs in the shapes and sizes of the bones. Some of the changes in the bones are allometrically linked to overall palate size, which varies more than 100-fold among the taxa in our sample. Often, these allometries were only hinted at in traditional independent contrasts-based regressions of log transformed data, particularly because many allometries are subtle, their slopes may vary among subclades, and the scatter around some trendlines is high. Rather, the allometries showed up in analyses of size-standardized palatal bone dimensions investigated using independent contrasts, bivariate phylomorphospace plots, and mirrored character reconstructions on the phylogenetic tree. We find negative allometry for parasphenoid lengths and widths essentially across the entire tree of Palaeozoic tetrapods, but with different trajectories characterizing the two largest clades, the temnospondyls and the lepospondyls. The lengths of several other elements may show positive allometries, either across the entire tree or in just a subclade. One possible positive allometry exists for the ectopterygoid, which appears to shorten allometrically in temnospondyls that evolve small body and palate size, and, as in Doleserpeton can be lost altogether. Both shortening and loss could be by the same developmental change, paedomorphosis, a form of heterochrony. Paedomorphosis might also account for evolution of relatively large parasphenoids in both lepospondyls and diminutive temnospondyls, but does not seem to explain evolution of ectopterygoid loss in lepospondyls. A regularity observed across nearly all taxa in our study set is an inverse correlation between the lengths of the vomer and pterygoid, bones that lie adjacent to one another along the long palatal axis. Further work is needed to learn whether such correlated evolution might be due to adaptation and/or to developmental bias, and particularly to learn how correlations and allometries themselves evolve.

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.

Schizodon scotorhabdotus is described from the Rio Orinoco system of Venezuela and Colombia. Its most similar congener, S. isognathus, is redescribed from the Rio Paraguay system of Brazil, Bolivia, and Paraguay, and a lectotype is designated for the species. Schizodon scotorhabdotus and S. isognathus can be distinguished from each other and from the most similar congener, S. knerii, by circumpeduncular and transverse scale counts, jaw orientation and osteology, and details of coloration. A principal components-based comparison of S. isognathus, S. knerii, and S. scotorhabdotus revealed that the three cited species also differ in mean body shape, particularly in body width. Comments are included on geographic distribution, life coloration, diet, and ontogenetic variation, including notable shifts in mouth position and caudal-fin morphology of these species.

This study develops the random phylogenies rate test (RAPRATE), a likelihood method that simulates morphological evolution along randomly generated phylogenies, and uses it to determine whether a considerable difference in morphological diversity between two sister clades of South American fishes should be taken as evidence of differing rates of morphological change or lineage turnover. Despite identical ages of origin, similar species richness, and sympatric geographic distributions, the morphological and ecological diversity of the superfamily Anostomoidea exceeds that of the Curimatoidea. The test shows with 90% confidence (using variance among species as the measure of morphological diversity) or 99% confidence (using volume of occupied morphospace) that the rate of morphological change per unit time in the Anostomoidea likely exceeded that of the Curimatoidea. Variation in the rate of lineage turnover (speciation and extinction rates) is not found to affect greatly the morphological diversity of simulated clades and is not a likely explanation of the observed difference in morphological diversity in this case study. Though a 17% or greater delay in the onset of diversification in the Curimatoidea remains a possible alternative explanation of unequal morphological diversification, further simulations suggest that two clades drawn from the possible treespace of the Anostomoidea and Curimatoidea will rarely differ so greatly in the onset of diversification. Several uniquely derived morphological and ecological features of the Anostomoidea and Curimatoidea may have accelerated or decelerated their rate of morphological change, including a marked lengthening of the quadrate that may have relaxed structural constraints on the evolution of the anostomoid jaw.

Morphometric analyses of 220 specimens of a characid, Bryconops sp. cf. melanurus, from the Brazilian Pantanal were used to describe allometric growth in that species and determine whether specimens from highland habitats were more streamlined than those from lowland habitats. Relative warp analysis of 14 landmarks and principal component analysis of 28 interlandmark distances returned complementary results. The increased streamlining of the highland specimens is highly consistent with known inductive effects of high water velocity on fish phenotypes. Genetic differentiation and inductive effects of temperature variation are also potential explanations of the observed phenotypic differentiation.

Pseudanos winterbottomi n. sp. from the Orinoco drainage of Venezuela and the Tapajos 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, Gnatho...

Several evolutionary theories predict that rates of morphological change should be positively associated with the rate at which new species arise. For example, the theory of punctuated equilibrium proposes that phenotypic change typically occurs in rapid bursts associated with speciation events. However, recent phylogenetic studies have found little evidence linking these processes in nature. Here we demonstrate that rates of species diversification are highly correlated with the rate of body size evolution across the 30,000+ living species of ray-finned fishes that comprise the majority of vertebrate biological diversity. This coupling is a general feature of fish evolution and transcends vast differences in ecology and body-plan organization. Our results may reflect a widespread speciational mode of character change in living fishes. Alternatively, these findings are consistent with the hypothesis that phenotypic 'evolvability'-the capacity of organisms to evolve-shapes the dynamics of speciation through time at the largest phylogenetic scales.

Background Scientists rarely reuse expert knowledge of phylogeny, in spite of years of effort to assemble a great “Tree of Life” (ToL). A notable exception involves the use of Phylomatic, which provides tools to generate custom phylogenies from a large, pre-computed, expert phylogeny of plant taxa. This suggests great potential for a more generalized system that, starting with a query consisting of a list of any known species, would rectify non-standard names, identify expert phylogenies containing the implicated taxa, prune away unneeded parts, and supply branch lengths and annotations, resulting in a custom phylogeny suited to the user’s needs. Such a system could become a sustainable community resource if implemented as a distributed system of loosely coupled parts that interact through clearly defined interfaces. Results With the aim of building such a “phylotastic” system, the NESCent Hackathons, Interoperability, Phylogenies (HIP) working group recruited 2 dozen scientist-programmers to a weeklong programming hackathon in June 2012. During the hackathon (and a three-month follow-up period), 5 teams produced designs, implementations, documentation, presentations, and tests including: (1) a generalized scheme for integrating components; (2) proof-of-concept pruners and controllers; (3) a meta-API for taxonomic name resolution services; (4) a system for storing, finding, and retrieving phylogenies using semantic web technologies for data exchange, storage, and querying; (5) an innovative new service, DateLife.org, which synthesizes pre-computed, time-calibrated phylogenies to assign ages to nodes; and (6) demonstration projects. These outcomes are accessible via a public code repository (GitHub.com), a website (http://www.phylotastic.org), and a server image. Conclusions Approximately 9 person-months of effort (centered on a software development hackathon) resulted in the design and implementation of proof-of-concept software for 4 core phylotastic components, 3 controllers, and 3 end-user demonstration tools. While these products have substantial limitations, they suggest considerable potential for a distributed system that makes phylogenetic knowledge readily accessible in computable form. Widespread use of phylotastic systems will create an electronic marketplace for sharing phylogenetic knowledge that will spur innovation in other areas of the ToL enterprise, such as annotation of sources and methods and third-party methods of quality assessment.

George Gaylord Simpson famously postulated that much of life's diversity originated as adaptive radiations-more or less simultaneous divergences of numerous lines from a single ancestral adaptive type. However, identifying adaptive radiations has proven difficult due to a lack of broad-scale comparative datasets. Here, we use phylogenetic comparative data on body size and shape in a diversity of animal clades to test a key model of adaptive radiation, in which initially rapid morphological evolution is followed by relative stasis. We compared the fit of this model to both single selective peak and random walk models. We found little support for the early-burst model of adaptive radiation, whereas both other models, particularly that of selective peaks, were commonly supported. In addition, we found that the net rate of morphological evolution varied inversely with clade age. The youngest clades appear to evolve most rapidly because long-term change typically does not attain the amount of divergence predicted from rates measured over short time scales. Across our entire analysis, the dominant pattern was one of constraints shaping evolution continually through time rather than rapid evolution followed by stasis. We suggest that the classical model of adaptive radiation, where morphological evolution is initially rapid and slows through time, may be rare in comparative data.

Synthetic science promises an unparalleled ability to find new meaning in old data, extant results, or previously unconnected methods and concepts, but pursuing synthesis can be a difficult and risky endeavor. Our experience as biologists, informaticians, and educators at the National Evolutionary Synthesis Center has affirmed that synthesis can yield major insights, but also revealed that technological hurdles, prevailing academic culture, and general confusion about the nature of synthesis can hamper its progress. By presenting our view of what synthesis is, why it will continue to drive progress in evolutionary biology, and how to remove barriers to its progress, we provide a map to a future in which all scientists can engage productively in synthetic research.

Understanding how and why certain clades diversify greatly in morphology whereas others do not remains a major theme in evolutionary biology. Projecting families of phylogenies into multivariate morphospaces can distinguish two scenarios potentially leading to unequal morphological diversification: unequal magnitude of change per phylogenetic branch, and unequal efficiency in morphological innovation. This approach is demonstrated using a case study of skulls in sister clades within the South American fish superfamily Anostomoidea. Unequal morphological diversification in this system resulted not from the morphologically diverse clade changing more on each phylogenetic branch, but from that clade distributing an equal amount of change more widely through morphospace and innovating continually. Although substantial morphological evolution occurred throughout the less diverse clade's history, most of that clade's expansion in morphospace occurred in the most basal branches, and more derived portions of that radiation oscillated within previously explored limits. Because simulations revealed that there is a maximum 2.7% probability of generating two clades that differ so greatly in the density of lineages within morphospace under a null Brownian model, the observed difference in pattern likely reflects a difference in the underlying evolutionary process. Clade–specific factors that may have promoted or arrested morphological diversification are discussed.