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    Session 37: General Ichthyology III (first 3)/ Morphology at NMNH (last 7)

    Room: Ballroom 111C

    2022-07-30   13:30 - 16:00

    Moderator: Dave Johnson



    1.  13:30  Nutrient Contributions from Highly Invasive Armored Catfish to a Florida Spring. Elizabeth Tristano*, Stetson University; Missy Gibbs, Stetson University   mgibbs@stetson.edu

    Invasive species may influence nutrient availability in habitats to which they are introduced. Such changes within a freshwater ecosystem can alter primary producer density or community composition, which is likely to have cascading effects at higher trophic levels. One invasive fish species that may be altering nutrient availability in its invaded habitat is the vermiculated suckermouth sailfin armored catfish (Pterygoplichthys disjunctivus), which is abundant in Florida springs. Armored catfish are anatomically unique from native Florida species due to the presence of thick armor plating, and thus we predicted that contributions to nutrient cycling made by armored catfish would differ significantly from those of native species. To test this, we measured N and P concentrations in the body tissues of adult catfish, as well as in their gut contents and excreta (an earlier study explored N and P in egesta). We also measured whole-body nutrient concentrations of native adult bluegill and eastern mosquitofish and of juvenile catfish. Body N:P was lower in adult catfish than in either native species and juvenile catfish. Excretion N:P was higher than literature values for native species, and hindgut N:P was markedly higher than foregut values. Our findings demonstrate that unlike native species, catfish are a P sink, likely due to the armor plating on the bodies of adult catfish. As armored catfish continue to maintain high abundances in Florida and around the world, they are likely to be initiating ecosystem-level disruptions by altering nutrient availability.


    2.  13:45  Invasive Lionfish on Caribbean Deep-Reefs. Luke Tornabene*, University of Washington; Megan Ewing, University of Washington; Rachel Welicky, Neumann University; Ross Robertson, Smithsonian Tropical Research Institute; Carole Baldwin, National Museum of Natural History: Smithsonian Institution   luke.tornabene@gmail.com

    Invasive lionfish (Pterois volitans) were introduced into the Caribbean in the late 1980’s and have spread throughout the Western Atlantic. Their high abundance, broad diets, lack of native predators and prolific spawning have resulted in dramatic reductions in populations of native prey species in several locations throughout their introduced range. The Smithsonian-led Deep Reef Observation Project (DROP) has documented lionfish on deep reefs at Curacao, Bonaire, Dominica, St. Eustatius and Roatan, where they occur to depths of at least 260 m. Here we present our preliminary data on the depth distributions of lionfish on deep reefs at these sites, as well diet data from stable isotope analysis of shallow- and deep-reef lionfish collected from Curacao. Our results show that lionfish on deep reefs are feeding at higher trophic levels and may have a broader diet than those on shallow reefs. Future research will use gut content metabarcoding to directly compare prey items of lionfish from the entire reef slope.


    3.  14:00  Updating and Expanding FishNet2 to Sustain Its Use in High Impact, Global, Ichthyological Research. Yasin Bakis, Tulane University; Xiaojun Wang, Tulane University; Hank Bart, Tulane University   yasinbakis@gmail.com

    FishNet has been serving quality metadata on fish specimens in ichthyological research collections for the past 20 years and it has been the most trusted biodiversity portal for scholarly research on fishes. However, the proprietary software on which the platform was built is past the end of service life and needs to be updated.


    4.  14:15  Evolution of the gular muscles in ray-finned fishes. Alessio Datovo*, Museu de Zoologia, USP; Paulo Presti, Museu de Zoologia, USP; George Vita, Museu de Zoologia, USP; Murilo Pastana, National Museum of Natural History; Luiz Peixoto, Universidade Federal do Para, NEAP   adatovo@usp.br

    The gular muscles cover the ventral surface of the head of jawed fishes. These muscles develop from ventral portions of the constrictor muscle plates of the two anteriormost pharyngeal arches. Ray-finned fishes usually exhibit four main gular muscle masses. Two of them derive from the mandibular muscle plate—the intermandibularis anterior and intermandibularis posterior—and two from the hyoid plate—the interhyoideus and hyohyoideus. A broad comparative investigation of key chondrichthyan, sarcopterygian, and actinopterygian taxa revealed several previously unknown evolutionary changes occurring in the gular musculature during the early radiation of Actinopterygii. New synapomorphies were discovered for some of the largest bony fish clades. The constrictor hyoideus ventralis of most actinopterygians differentiates at origin into an interhyoideus and a hyohyoideus. The interhyoideus directly attaching to the lower jaw via an anterolateral aponeurosis is a synapomorphy for Neopterygii. Teleosts uniquely have an interhyoideus segmented ventrally into anterior and posterior sections by an intermediate aponeurosis or raphe. They also have the lateral portion of the hyohyoideus completely separated from each other, thus forming an anterior hyohyoideus inferior and a posterior hyohyoideus superior. Our data and an exhaustive review of the literature also indicate significant taxonomic and possibly intraspecific variations in the innervation patterns of the gular muscles across different fish lineages.


    5.  14:30  What is the sister group of the Saccopharyngoidei (Teleostei: Anguilliformes)? Vinicius Espindola*, Smithsonian National Museum of Natural History; David Johnson, Smithsonian National Museum of Natural History   espindolavc@gmail.com

    When John Harwood described the deep-sea eel, Saccopharynx, in 1827, he called the specimen a “very extraordinary animal.” The colossal jaws, reduced head, long, slim body, posteriorly displaced branchial arches and pectoral fins, and a light organ on the caudal fin caught the attention of ichthyologists worldwide. Subsequently, more and similarly peculiar deep-sea fishes were collected and grouped together. Saccopharynx and the relatively similar Eurypharynx and extraordinaryMonognathus were assigned to the Lyomeri (= Saccopharyngoidei sensu Berg), which Gill and Ryder characterized by an imperfectly ossified cranium articulating with the first vertebra by a basioccipital condyle, maxilla absent and mandible in a single bone. In 1974 Solomon Raju added Cyema to the Saccopharyngoidei, and all subsequent classifications recognize the monophyly of this suborder. Morphological and molecular, numerous authors have hypothesized and discussed alternative placements of the group within Anguilliformes, or, putatively, even with other teleost groups. In this study, we compare the morphology of the 20 families of the Anguilliformes and several outgroup taxa, with particular emphasis on cephalic musculature. Among other things, we found that the members of the Nemichthyidae share with all taxa of the Saccopharyngoidei a distinctive second section of the levator operculi that inserts on the posterior portion of the angulo-retroarticular. Additionally, they share, uniquely among angulliforms, a significant dorsomedial expansion of the maxilla and absence of the preopercle and ectopterygoid. Based on this evidence, we conclude that nemichthyids are the sister group of the Saccopharygoidei.


    6.  14:45  Diversity of the Osteology and Myology of the Hyoid Bar in Beloniformes (Teleostei: Atherinomorpha). Daniel Lumbantobing*, Smithsonian National Museum of Natural History; Lynne Parenti, Smithsonian National Museum of Natural History   lumbantobingd@si.edu

    The hyoid bar shows a high degree of osteological variation among atherinomorph fishes, including number and position of the branchiostegal rays. Although previous studies have advanced our knowledge of its osteology, little is known about the musculature of this ventralmost portion of the skull in atherinomorphs. In the Atherinomorpha, two types of the hyohyoidei muscle generally present: the hyohyoidei inferioris and the hyohyoidei superioris. The hyohyoidei inferioris constitutes a muscle bundle arising from the ventromedial face of the anterior ceratohyal and passing ventromedially to insert on the dorsomedial faces of the anterior branchiostegal rays on the same side. In contrast, the hyohyoidei superioris consists of a tendinous bundle arising from the ventrolateral face of the ventral hypohyal, passing ventromedially, and crossing the midline to insert on the ventromedial face of the anterior branchiostegal rays on the opposite side, thus appearing crisscrossed anteriorly. In ricefishes (atherinomorph family Adrianichthyidae), a unique pair of muscle sheets—the ventroposterior section of the hyohyoidei superioris—is present along the ventroposterior-most of the hyoid bar, arising from a median raphe (ventral to the urohyal bone and the sternohyoideus muscle) and passing ventrolaterally to attach to the ventromedial faces of the branchiostegal rays. A similar pair of muscles is found elsewhere among teleost fishes (e.g., some cypriniforms, gasterosteiforms, tetraodontiforms, and sicydiine gobies). This pair of muscles is absent in non-adrianichthyid beloniform fishes and other atherinomorph fishes examined, thus interpreted here as a synapomorphy that supports the monophyly of the family Adrianichthyidae.


    7.  15:00  The Evolution of Tunas, Mackerels, Snake Mackerels, and Billfishes Based on a Large-Scale Phenotypic Phylogeny. Murilo Pastana*, National Museum of Natural History; G. David Johnson, National Museum of Natural History; Alessio Datovo, National Museum of Natural History   murilopastana@gmail.com

    The order Scombriformes (sensu Johnson, 1986) is a large, diverse group of marine fishes with great economic relevance and media appeal that includes billfishes, tunas, mackerels, and barracudas. Whereas morphological studies support the monophyly of Scombriformes, molecular analyses resolve the group as polyphyletic, with Gempylidae, Trichiuridae, and Scombridae included in the Pelagiaria, and sphyraenids, xiphiids, and istiophorids clustered within Carangaria. The incongruence among these highly conflicting hypotheses raises many doubts regarding the evolution of extraordinary anatomical characteristics present in scombriforms or its subgroups, such as the intermediate aponeurosis of the external pharyngoclavicularis muscle, ontogenetic restructuring of the upper jaw, and the fusion of the cartilaginous gill-filament blades and concomitant investment with toothplates, and other unique features of the dorsal gill arches. Here, we reassess the phylogeny of Scombriformes based on an extensive matrix of phenotypic data. The final matrix includes characters from several underexplored anatomical systems (e.g. myology, arthrology, lateral-line sensory system) and encompass representatives of all families traditionally assigned to scombriforms along with those belonging to all other percomorphacean taxa suggested as possibly related to the order. This approach offers a modern overview of the evolution of the Scombriformes, providing the largest assessment to date regarding its phyletic status and interrelationships. Moreover, the resultant topology provides a backbone that allows discussions concerning character-reconstruction of the uncommon anatomical features present in Scombriformes, and documentation of morphological convergences and reversals currently required by molecular hypotheses for the interrelationship of the group.


    8.  15:15  Pelvic-fan Flaring and Inflation in the Three-Tooth Puffer, Triodon macropterus (Tetraodontiformes: Triodontidae). Katherine Bemis*, DOC/NOAA/NMNH/OST/NSL; James Tyler, Smithsonian Institution; Atsushi Kaneko, Okinawa Churaumi Aquarium; Keiichi Matsuura, National Museum of Nature and Science; Kiyomi Murakumo, Okinawa Churaumi Aquarium; Vinicius Espindola, Smithsonian Institution; Jean-Lou Justine, ISYEB; Diane Tyler, NA; William Bemis, Cornell University   lashaun.willis@noaa.gov

    Triodon macropterus, the Three-Tooth Puffer, is the only extant species of Triodontidae. It has a large pelvic fan that can be flared when disturbed. Unlike members of two closely related families, Tetraodontidae (pufferfishes) and Diodontidae (porcupinefishes), T. macropterus has not previously been documented to inflate its abdomen, although some nineteenth-century reports implied that it can. Those reports were dismissed in a mid-twentieth-century study, and no new information about inflation in T. macropterus has been reported in the intervening 70 years. Digital cameras and the Internet enable fishermen to document and share their photographs of unusual fishes, such as T. macropterus. We found 13 photographs on the Internet of freshly caught T. macropterus for which we could verify sources and locality data. The pelvic fan was prominently flared in all 13 images; in seven, the abdomen was also inflated. Live T. macropterus at the Okinawa Churaumi Aquarium, Japan, allow observations of behaviors. Our videography and ultrasound recordings of three captive individuals showed that fan flaring always precedes inflation. Ultrasound data confirmed that water is swallowed into the stomach to produce volume increases of 30%. We studied x-rays and dissections of three specimens and found that a thin-walled pyloric region of the stomach allows inflation to occur and to expand into the ventral abdominal recess. The anatomical substrates of inflation in T. macropterus differ from those of the best-known inflators, diodontids, and likely evolved independently but serve a similar behavioral role in defense.


    9.  15:30  Larva of the Gargoyle cusk (Xyelacyba myersi) and its relationship with the Bony-eared assfish (Acanthonus armatus). Matthew Girard*, National Museum of Natural History; Ai Nonaka, National Museum of Natural History; Carole Baldwin, National Museum of Natural History; G. David Johnson, National Museum of Natural History   mgirard@ku.edu

    The larvae of marine fishes often differ in appearance from their adult form. While visually striking, these larvae can be difficult to identify, and some have yet to be linked to an adult counterpart. The predominantly deep-sea family of cusk-eels (Ophidiidae) have an epipelagic larval stage that is remarkably diverse in appearance. Some of these larvae, such as the Bony-eared assfish, Acanthonus armatus, are widely popular among blackwater photographers due to their extremely elongate fin rays. During a dive off the east coast of Florida, a larva was photographed and collected that resembled a Bony-eared assfish due to the elongate upper pectoral-fin rays. However, our examination of this larval specimen identifies it as a Gargoyle cusk, Xyelacyba myersi; a species for which the larval stage has yet to be described. We describe this novel larva, comparing it to a newly caught larva of Acanthonus armatus from Hawaii, and highlight morphological similarities and differences between them. Given the overall similarity between these larvae, the results of our DNA analyses, and previous works suggesting a close relationship between the genera Acanthonus, Tauredophidium, and Xyelacyba, we then compare the adult morphology of these genera using µCT scanning, highlighting shared morphological traits and hypothesize relationships among them. Finally, we suggest taxonomic changes for these three monotypic genera so their classification is reflective of evolutionary hypotheses. Our study not only demonstrates the scientific importance of blackwater images and specimens for species identification, but also highlights their significance in understanding evolutionary relationships.




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