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    V: Ichthyology VI

    2021-07-26   09:00 - 10:15

    Moderator: Pamela Hart

    1.  09:00  VIRTUAL    Systematic Overview of Altigena, Bangana, and Incisilabeo(Cyprinidae: Labeoninae) in Southeast Asia. Patrick Ciccotto*, Warren Wilson College

    The freshwater genus BanganaHamilton has a complex taxonomic history. Originally erected as a subgenus of Cyprinus Linnaeus, Banganawas later considered invalid with constituent species placed in LabeoCuvier or SinilabeoRendahl. Banganawas resurrected in the mid-1980s and remains valid today. However, more recent examinations of oromandibular morphology and molecular phylogenetic analyses have revealed Bangana to be a polyphyletic assemblage, with the current recognition of Bangana and several other genera, including Altigena and Incisilabeo. The taxonomic statuses of species of Altigena, Bangana, and Incisilabeo from Myanmar east to China are herein reviewed. Altigena lippafrom the Lower Mekong is redescribed and A. laticeps from the Upper Mekong is revalidated, in addition to a revised diagnosis of A. sinkleri from the Chao Phraya in Thailand. Bangana devdevifrom the Irrawaddy and Salween River basins is redescribed, with a discussion of nomenclatural issues for this species. Incisilabeo, which was originally diagnosed based on the unique morphology of large adults, is differentiated from other species of Bangana based on examinations of comparably sized specimens.

    2.  09:15  VIRTUAL    Integrative Taxonomy As A Tool for Conservation: Exploring Freshwater Fish Diversity of the Barra del Colorado Wildlife Refuge, Costa Rica. Taegan JM Perez*, Department of Ecology and Evolutionary Biology, University of Toronto Scarborough; João Pedro Fontenelle, Institute of Forestry and Conservation, University of Toronto; Arturo Angulo, Museo de Zoología y Centro de Investigación en Ciencias del Mar y Limnología, Universidade de Costa Rica; Nathan R Lovejoy, Department of Ecology and Evolutionary Biology, University of Toronto Scarborough

    As concerns over global biodiversity declines continue, diversity information becomes increasingly important for effective conservation planning and management. Diversity investigations rely on accurate taxonomic identification, which can be an arduous task in incredibly diverse groups, like the Neotropical freshwater fishes. Morphology-based approaches are conventionally used to assess diversity but can be inefficient when intra- and interspecific morphological variation overlaps. Previous assessments of the diversity of freshwater fishes in Costa Rica are based on traditional morphological identification methods, and no studies to date have implemented molecular techniques such as DNA barcoding for this region. We used an integrative approach that combines morphological and molecular identification techniques to explore the fish diversity of the Barra del Colorado Wildlife Refuge, Costa Rica. This integrative approach documented 42 species and 35 genera, from survey efforts over multiple years. We identified six species not previously surveyed in the area and two non-native species. We identified lingering issues of misidentifications and incompleteness in publicly available barcode databases used for molecular identification and conservation. To remedy this, we propose the first curated DNA barcode library for the region, using critically evaluated public data and sequences from specimens collected in BCWR.

    3.  09:30  VIRTUAL    Phylogeography of the Chocó Endemic Rainbow Characin (Teleostei: Rhoadsia). Roberto Cucalon, DePaul University; Jonathan Valdiviezo-Rivera, Instituto Nacional de Biodiversidad; Pedro Jimenez-Prado, Pontificia Universidad Catolica del Ecuador Sede Esmeraldas; Ronald Navarrete-Amaya, NA; Virginia Shervette, University of South Carolina Aiken; Antonmio Torres-Noboa, Universidad de Guayaquil; Natasha Wierzal, DePaul University; Thomas Borders, DePaul University; Nathan Lujan, American Museum of Natural History; Windsor Aguirre*, DePaul University

    South America’s Chocó, part of the North Andean Pacific Slopes – Rio Atrato ecoregion, is a biodiversity hotspot with many rivers, yet phylogeographic studies of aquatic species are scarce. Rhoadsia is a Chocó endemic freshwater fish genus with two recognized species: R. minor from northwestern Ecuador and R. altipinna from southwestern Ecuador and northwestern Peru. We conducted a phylogeographic study using two mitochondrial genes and twelve microsatellite markers to examine the evolutionary history of Rhoadsia. Samples collected in drainages throughout Western Ecuador from sea level to 1260 m.a.s.l. were included, as were samples of species in the closely related genera Parastremma and Carlana from Colombia and Central America. Phylogenetic analysis of the mtDNA markers confirmed the reciprocal monophyly of a northern and southern clade in Ecuador, and the presence of mitochondrial haplotypes of both clades in the northern Guayas basin. Structure analysis with the microsatellite markers pointed to introgression at the border between the species ranges as the likely cause of the mixing of mitochondrial haplotypes in the northern Guayas. Bayesian analysis of the microsatellite data revealed the existence of at least ten populations throughout western Ecuador, divided into three main geographically segregated groups. GroupI coincided with the northern distribution of R. minor while groups II and III seemed to represent geographic subgroups of R. altipinna in the Guayas and southern coastal drainages. This study provides a baseline for future studies on the biogeography of Ecuadorian freshwater fishes and the adaptive evolution of morphologically divergent Rhoadsia populations.

    4.  09:45  VIRTUAL    Fish Presence, Species Richness, and Spatial Distribution in Intermittent Stream Pools. Krista Ward*, Wichita State University; Christine Streid, Wichita State University; Jake Wright, Wichita State University; Thomas Luhring, Wichita State University

    Intermittent streams ecosystems are extremely dynamic due to high variability of weather patterns between and within years, leading to a wide range of hydrological conditions (e.g., connectivity, pool volume, hydroperiod). Spatial distribution of stream fishes is affected by stream characteristics such as stream order and distance from a permanent stream body and by local pool characteristics such as pool volume and hydroperiod. The strength of the effect of physical pool characteristics may be determined by larger scale factors or an interaction of factors that predict the overall distribution of stream fish. We conducted a natural snapshot experiment by completing fish surveys of 117 stream pools across 7 intermittent streams in Elk County, Kansas from May 15th – July 15th, 2020. We focused on quantifying fish presence and species richness in relation to stream permanency, connectivity to nearest permanent body of water, volume of each pool, and local pool characteristics using individual stream pools. Our results show that fish presence is positively correlated with pool volume and stream permanency and that fish species richness is positively correlated with pool volume but negatively correlated with stream permanency. This study provides ecologically relevant information on the impacts of physical pool and landscape characteristics of intermittent streams across a human-altered landscape on fish species richness and distribution.

    5.  10:00  VIRTUAL    Total evidence phylogenetic analysis reveals polyphyly of Anostomoides and uncovers an unexpectedly ancient genus of anostomid fishes. Brian Sidlauskas*, Oregon State University; Fernando Assega, Universidade Estadual de Londrina; Bruno Melo, Universidade Estadual Paulista; Claudio Oliveira, Universidade; José Birindelli, Universidade Estadual de Londrina

    The nearly 150 species in Anostomidae comprise one of the most diverse and taxonomically dynamic families of Neotropical freshwater fishes. A recent revision of its enigmatic and poorly diagnosed genusAnostomoidesdemonstrated that this taxon contains two valid species, each with complicated taxonomic histories, but did not address their phylogenetic placement. Herein, we integrate molecular and morphological data to demonstrate their distant evolutionary relationship, and thus the polyphyly ofAnostomoides. While we reconstruct one of the species in a previously hypothesized placement within a clade also containingLaemolyta,RhytiodusandSchizodon, the other unexpectedly represents a morphologically and genetically distinctive lineage that diverged early in the family’s history and has evolved independently for approximately 37 million years. The unusual combination of characters in this new genus casts new light on the early anatomical diversification of Anostomidae and illustrates how the addition of a single taxon can revise ancestral state reconstructions.

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