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    Session 27: ASIH Stoye Genetics, Development, and Morphology II

    Room: Ballroom 111C

    2022-07-29   13:30 - 16:00

    Moderator: Stacy Farina



    1.  13:30  Many Ways to Build an Angler: An Analysis of Feeding Morphologies in Deep Sea Anglerfishes (Ceratioidei: Lophiiformes). Zach Heiple*, University of Oklahoma & Sam Noble Oklahoma Museum of Natural History; Jonathan Huie, The George Washington University; Pam Hart, University of Oklahoma & Sam Noble Oklahoma Museum of Natural History; Christopher Goatley, School of Environmental and Rural Science, University of New England; Dahiana Arcila, University of Oklahoma & Sam Noble Oklahoma Museum of Natural History; Elizabeth Miller, University of Oklahoma & Sam Noble Oklahoma Museum of Natural History   zachheiple15@gmail.com

    Deep sea anglerfishes (suborder: Ceratioidei) are an enigmatic clade of bathypelagic fishes in the order Lophiiformes. Ceratioids are difficult to observe in situ and little is known about their ecology. Food is scarce in the bathypelagic zone, thus ceratioids use novel innovations including bioluminescent lures and large gapes seemingly to eat any prey within reach. However, due to the lack of behavioral studies, the nuances of ceratioid feeding remain unresolved. To this end, we identified remarkable diversity in the feeding morphologies of ceratioids that may suggest variable feeding modes. Our analyses included 43 ceratioid species (25.3% of the total species diversity), representing 10 out of 11 families, as well as 15 benthic lophiiform outgroups. We used micro-CT scans to measure functional feeding traits including tooth height, tooth spacing, and jaw shape as proxies for diet and feeding behavior. We used hierarchical clustering to identify groups with similar oral morphologies and create hypotheses about ecological specialization among ceratioids. To inform our morphological analyses, we generated novel phylogenetic hypotheses using genome-wide exonic datasets (1,105 loci). Our results highlight a gradient in anglerfish dentition. On one extreme, some species of ceratioids are equipped with tightly packed and small teeth that are well suited for enduring the stresses of biting. Teeth of the opposing extreme are elongate, thin, and broadly spaced, suggesting they are poorly suited for the stresses of biting. This variation suggests that ceratioid feeding may be more diverse than previously thought, or that there is no single generalist morphology for ceratioids.


    2.  13:45  Anatomy and phylogenetic implications of prenasal segments in Carangiformes (Teleostei: Percomorphacea): a character investigation. Gabriel Afonso*, University of São Paulo; Murilo Pastana, Sara E. and Bruce B. Collette Postdoctoral Fellowship in Systematic Ichthyology, National Museum of Natural History, Smithsonian Institution; Flávio Bockmann, University of São Paulo   gabrielvfa@usp.br

    Carangiformes encompasses three major acanthomorph taxa: Carangidae, Echeneoidea, and Nematistiidae. According to morphological phylogenies, Carangidae is composed of four tribes (Carangini, Naucratini, Scomberoidini, and Trachinotini). The monophyly of Carangidae is supported by a single anatomical characteristic, i.e. the posteroventral elongation of the first anal pterygiophore; and the family is placed as sister-group of Echeneoidea by sharing two prenasals. The prenasals are canal segments of the lateral line system located anterior to the nasal, and may be ossified or not. According to the literature, Echeneoidea has two ossified prenasals, while Carangidae has the anterior prenasal unossified, and the posterior ossified. Contrastingly, molecular phylogenies indicate the paraphyly of Carangidae, grouping Scomberoidini and Trachinotini with Echeneoidea, and this clade as sister-group of Carangini + Naucratini. In the present study, character distribution of prenasals is mapped within Carangiformes and evaluate its phylogenetic impact in divergent relationship hypotheses. Our results differ from the literature as we observe only Carangini and Naucratini with the anterior prenasal unossified, while both Scomberoidini and Trachinotini have the anterior prenasal ossified. Thus, according to morphological phylogenies, the presence of anterior prenasal ossified is optimized as homoplasy in Echeneoidea and in Scomberoidini + Trachinotini, totalizing three evolutionary steps. In molecular phylogenies, instead, the presence of anterior prenasal ossified is optimized as synapomorphy for Echeneoidea + Scomberoidini + Trachinotini, resulting in two evolutionary steps. This study confronts the internal relationships in Carangiformes and offers the first morphological character corroborating the Carangidae paraphyly, as indicated by molecular phylogenies.


    3.  14:00  First Description of the Osteology of the West African Stargazer, Uranoscopus cadenati. Leo MacLeod*, University of Washington; Katherine Bemis, NOAA National Systematics Laboratory, National Museum of Natural History, Smithsonian Institution; Murilo Pastana, Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution   leomac18@uw.edu

    The family Uranoscopidae, commonly known as stargazers, includes > 50 species in seven valid genera and are found worldwide in shallow waters of the tropical to temperate oceans. Uranoscopus cadenati, the West African Stargazer, is one of four species of Uranoscopus found along the west coast of Africa. Only the original species description and an FAO guide have described external morphology of U. cadenati and no papers have focused on its osteology. To study the osteology of the species, we used micro-computed tomography scanning (µCT) and clearing and staining techniques. We found that the outer surface of the cranium, as well as the opercular series, is highly rugose except for smooth lateral line canals. Uranoscopus cadenati has a large basipterygial process that breaks the skin and protrudes anteriorly as a spine. The pelvic bone has a dorsolateral process between the basipterygial process, and the main pelvic girdle that forms a ‘cup’ supporting the cleithrum, which terminates anterior to the pelvic spines. 3D visualization and clearing and staining techniques allowed us to map the sensory canal system, and compare different hypotheses on the placement of ribs and epineurals. Our study will serve as a reference for future osteology studies of this genus and family, especially because this is the first time CT-scanning and clearing and staining methods are coupled to describe and visualize the entire skeleton of an Uranoscopidae.


    4.  14:15  Finite Element Modelling of Limb Bone Fusion in Anurans. Rachel Keeffe*, University of Florida; David Blackburn, University of Florida   rmkeeffe@gmail.com

    Within vertebrates, many clades exhibit fusion between elements of the appendicular skeleton. Notable examples include the limbs of modern birds, mammals, and frogs. The function of limb bone fusion is often stated to increase the strength of the limb to facilitate rapid movements, usually in the context of energetic locomotor modes like running, flying, and jumping. Frogs stand out among other vertebrates because adults of all living species, regardless of locomotor mode, exhibit fusion of the zeugopod elements (radius and ulna, tibia and fibula). Frogs span a diversity of locomotor types beyond saltation (e.g., jumping) and many frogs do not or cannot jump. What are the functional benefits of limb bone fusion for frogs? How does fusion of these elements benefit frogs during saltation? In this project, we use finite element modelling methods to assess the functional consequences of fusion in the anuran radioulna, the forearm bone of frogs important to both locomotion and amplexus. Using CT scans of museum specimens and mesh-editing software, we evaluated how different degrees of fusion between the radius and ulna affect the effective stress of the zeugopod in different loading scenarios. We find that the semi-fused state observed in the radioulna may exhibit less effective stress than unfused or completely fused models in certain loading conditions. This may indicate that radioulna morphology is optimized to minimize effective stress across different loading regimes. This work provides new insight into the functional consequences of limb bone fusion in the context of anuran evolution.


    5.  14:30  An Analysis of the Developmental Osteology of Giant Sea Bass (Stereolepis gigas). Emily Ladin*, Cal State University Northridge; Larry Allen, Cal State University Northridge   emily.ladin.661@my.csun.edu

    Giant sea bass (Stereolepis gigas), are listed as critically endangered by the IUCN, and are the largest bony fish off the coast of Southern California. After fertilization, giant sea bass larvae develop in the plankton and eventually settle to a sandy bottom habitat, but little is known about their early life history stages or what mechanisms drive this transition. This study aims to examine, in detail, the first critical stages of this species including the pre-flexion, flexion, post-flexion, and the transformation stages. Laboratory reared specimens were collected throughout development and preserved. The fixed larvae were double stained with alcian blue and alizarin red, while a small subset were single stained with alizarin red. Osteological development was analyzed amongst the different sized larvae. The morphometric formulas for seven elements are as follows: vertebral column- precaudal 12, caudal 13; dorsal fin X-I, 11; anal fin III, 9; pelvic fin I, 5; pectoral fin 20; caudal fin- principal rays 9+8, procurrent rays- upper 9, lower 9; branchiostegals 7. Knowledge of these developmental stages will give us a better understanding of what is driving giant sea bass larval recruitment, thus allowing better protection of nursery areas and rational fisheries management.


    6.  14:45  Olfactory Organ Anatomy across Deep-sea Lanternfishes. Rene Martin*, University of Kansas   rpmartin@ku.edu

    Vision, olfaction, and mechanoreception are three important sensory systems in fishes for behaviors like feeding, mate location, and schooling. Within deep-sea fish lineages, living in highly pressurized low-light environments, there exists a wide range of adaptations to these systems. Specifically, the olfactory system allows fishes to obtain information from remote sources, farther than visual and sound-based sensory systems. Olfaction is especially important for finding prey and conspecifics in fishes living in these deep-sea environments. Fishes thrive across a diversity of aquatic habitats, and the morphologies of their olfactory organs, specifically their nasal rosettes, are similarly variable, with larger numbers of lamellae usually correlating with increased olfaction sensitivity. Although there is variability in olfactory organ morphology across all fishes and a trend of increasing numbers of lamellae with increasing age, many fish families possess species that have olfactory organs of a similar type. Analysis of the olfactory organs of lanternfishes (Myctophidae), small midwater fishes, suggests a possible contrast to this general trend. In order to increase our understanding of olfaction across lanternfishes and deep-sea fishes in general, I perform a detailed anatomical study of myctophid olfactory organs combined with phylogenetic comparative methods.


    7.  15:00  Bridging Macro- and Micro-evolution in Tropical Reef Blennies (Labrisomidae: Malacoctenus). Carmen Pedraza-Marrón*, University of Oklahoma; Ricardo Betancur-R., University of Oklahoma   carmen.pedraza@ou.edu

    The study of spatio-temporal phylogenetic concordance of co-distributed lineages—comparative phylogeography—provides invaluable insights into understanding the influence of historical (e.g., geophysical events) and contemporary barriers (e.g., habitat gaps) hindering genetic flow among populations. In this study, we use genome-wide approaches to test the effect of recognized historical and contemporary barriers for labrisomid blennies in the genus Malacoctenus, distributed in the Tropical Eastern Pacific (TEP) and the Greater Caribbean (GC) biogeographic regions. They represent an ideal system to test the effect of historical (e.g., the rising of the Isthmus of Panama) and contemporary (e.g., sandy gaps) barriers as they are strongly associated with rocky habitats and coral reefs, where subtle habitat disruptions may lead to genetic isolation. We generate ~9,000 genome-wide ddRADseq markers for 506 individuals of 22 (of 24) species of Malacoctenus, to investigate the spatial and temporal correspondence between population genetic structure and previously-identified barriers across these regions. The phylogenetic relationships of the genus indicate the existence of two transisthmian clades that appear to have co-evolved in synchrony in both space and time. At micro-evolutionary scales, the genetic structure of populations of widely-distributed species suggests spatial congruence for the Central American Gap in the TEP (two species) and the Central Bahamas break in the GC (four species). For two GC species, the Western and Eastern breaks promoted further population structure. All in all, our preliminary results suggest spatial concordance of population-level divergences, largely aligning with many of the previously identified phylogeographic breaks in the TEP and GC regions.


    8.  15:15  Characterizing the lesser known larval fishes of the Southern Ocean. Andrew Corso*, Virginia Institute of Marine Science; Jan McDowell, Virginia Institute of Marine Science; Ellen Biesack, Virginia Institute of Marine Science; Sarah Muffelman, Virginia Institute of Marine Science; Eric Hilton, Virginia Institute of Marine Science   adcorso@email.wm.edu

    Fishes in the suborder Notothenioidei represent the majority of the ichthyofaunal diversity in the Southern Ocean. Although much attention has been devoted to characterizing some groups of notothenioids (e.g., nototheniids or channichthyids), several groups are poorly studied, especially during their early life stages. As areas of the Southern Ocean continue to rapidly change due to warming and sea ice loss, it is important to better understand the diversity of this unique fish assemblage prior to irreversible ecosystem damage. We examined a novel collection of preserved larval fishes sampled along the western Antarctic Peninsula over the last 30+ years to analyze the larval traits of several lesser known notothenioids, including representatives from the Bathydraconidae and Artedidraconidae. Using this unique collection, we offer the first larval description of the least-fecund bathydraconid – Akarotaxis nudiceps. We also describe the development of Prionodraco evansii, the only Antarctic larval fish with modified spiny scales. We use these data to infer possible life histories, the ecology of several Antarctic larval fishes, and propose future areas of study.


    9.  15:30  Developmental Exposure to Ecologically Relevant Levels of a Carbamate Pesticide Causes Changes in Brain Structure in Amphibians. Delanie Crabtree*, Moravian University; Sara McClelland, Moravian University   crabtreed@moravian.edu

    Carbaryl is a common pesticide used in the U.S. for combating insect infestations. When carbaryl is agriculturally used, it often contaminates natural habitats through run-off. Contaminated habitats can result in chemical exposure to vertebrate animals. Previous studies have shown that carbaryl, a carbamate pesticide, reversibly inhibits acetylcholinesterase, affecting movement and muscle function in model organisms, and at high doses can lead to uncontrollable urination, seizures, and death. However, it is unclear how low dose exposures, more commonly encountered in nature, impact health and physiology. Amphibians are especially at risk of this contamination because they are tied to these habitats for mating and larval development. We hypothesized that environmentally realistic exposures to carbamates would impact amphibian neurodevelopment and behavior in a non-monotonic manner. To test this hypothesis, we exposed Pickerel Frog (Lithobates [Rana] palustris) tadpoles to either a vehicle control, 1 ppb, or 10 ppb of carbaryl in a blind laboratory experiment. After two weeks of exposure, three behavioral assays were performed to test boldness, olfactory sensitivity, and muscle movement, and then body and brain morphology were analyzed. Results showed that there was an effect of 1 ppb carbaryl on the size of the diencephalon length and the telencephalon width. There was no effect of exposure to 10 ppb carbaryl on brain morphology. There were no effects of either carbaryl dose on body morphology. While future studies are still needed, this work demonstrates that low-dose carbamate exposures can impact amphibians in a non-monotonic manner.


    10.  15:45  Population Connectivity in Agricultural Landscapes: Land Use Effects on Gene Flow in the Northern Leopard Frogin the Prairie Pothole Region. Justin Waraniak*, North Dakota State University; David Mushet, Northern Prairie Wildlife Research Station, USGS; Craig Stockwell, North Dakota State University   jmwara@umich.edu

    The Prairie Pothole Region (PPR) is one of the most wetland dense regions in the world, however, land-use conversion to agriculture has fragmented prairie habitats in the PPR, with upland prairie wetlands particularly targeted for conversion. This fragmentation can lead to negative consequences for wetland obligate organisms, heightening the risk for inbreeding depression, local extinction, and reducing the evolutionary potential for populations to adapt to changing environmental conditions. This study models biotic connectivity of prairie-pothole wetlands using a genetic analysis of populations of northern leopard frog (Rana pipiens). Twenty frogs from each of 22 sites in the James River and Lake Oahe river basins in North Dakota were genotyped using Best-RAD sequencing at 2868 bi-allelic single nucleotide polymorphisms (SNPs). Clustering analyses of population structure indicated weak spatial structure of six population clusters loosely organized along a northwest to southeast gradient. Circuit theory-based landscape resistance analysis suggested land use, including row crop agriculture, and topography were the primary influences on genetic differentiation among the twenty-two sample sites. There was a noticeable difference in the patterns of connectivity between the James River valley, which was dominated by row crop agriculture, versus the Missouri Coteau where topography played a greater role. This information can help identify important amphibian dispersal corridors and prioritize lands for conservation and/or restoration.




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