TAES 142: 167-213 RESEARCH ARTICLE ISSO 0002-8320 http://taes.entomology-aes.org/ Hydrochidae (Coleoptera) of Mississippi REESE J. WorthinGton1, JOHN L. HELLMAN2, PAUL K. LAGO 1 1Department of Biology, University of Mississippi, University, MS 38677. Corresponding author email: [email protected]. 2Department of Entomology, University of Maryland, College Park, MD 20742. ABSTRACT Mississippi Hydrochidae are poorly known. In this paper, we attempt to untangle some of the taxonomic difficulties caused by recent dubious works of D. Makhan and to validate an undescribed species from previously unpublished research. The 12 species occurring in Mississippi are reviewed and one new species, H. falsus Hellman sp.n., is described. Six new synonymies are established as follows: Hydrochus hanoewanti Makhan, 1994 is a junior synonym of Hydrochus rugosus Mulsant, 1844; Hydrochus monishi Makhan, 1995 is a junior synonym of Hydrochus foveatus Haldeman, 1852; Hydrochus equicarinatus Blatchley, 1928 is a junior synonym of Hydrochus simplex LeConte, 1855; Hydrochus daviniaae Makhan, 1995 is a junior synonym of Hydrochus vagus LeConte, 1851; Hydrochus bakkeri Makhan, 1995 is a junior synonym of Hydrochus obscurus Sharp, 1882; and Hydrochus soesae (Makhan), 2004 is a junior synonym of Hydrochus scabratus Mulsant, 1844. Hydrochus inaequalis LeConte, 1855 is removed from synonymy with Hydrochus foveatus Haldeman, 1852 and resurrected as a proper species. Neotypes are designated for H. rugosus Mulsant, 1844, H. rufipes Melsheimer, 1844, and H. scabratus Mulsant, 1844. A lectotype is designated for H. foveatus Haldeman, 1852. Species descriptions, illustrations of male genitalia, distribution maps and a key to species are presented. Additional notes on Makhan species and holotypes, including unavailable types, are provided. Key words: Hydrochidae, Hydrochus, Mississippi, taxonomy INTRODUCTION professionalism is well known and has extended well beyond Hydrochus into several other groups Taxonomy of North American Hydrochidae, (Hansen 1998, 1999; Jäch 2000; Short and Hebauer containing only the nearly cosmopolitan genus 2006; Steiner et al. 2003; Oliva 2000; Watts 1999). Hydrochus, has been in a state of disarray for Taxonomic confusion within the genus has been nearly a century. This was true during the first part created primarily by great variation in external of the 1900’s primarily because species descriptions features, eg. color, size and surface sculpturing, were poorly written, keys were not available or which is often readily apparent within individual not diagnostic, types were either inaccessible populations of the various species. In most cases, or ignored by authors, and the importance of positive species identification requires examination male genitalia in diagnosing species was not of male genitalia, while females can, generally, be yet recognized. More recently, the problem was identified only by association with males from the exacerbated by the various works of Dewanand same locality or collecting event. Makhan involving North American members of In 1975, Hellman produced a comprehensive the genus (Makhan 1994, 1995a, 1995b, 1996, study of the North American members of the 2000, 2001, 2004a, 2004b, 2005). Makhan’s genus Hydrochus as a dissertation project. Prior continuous application of poor taxonomic concepts, to this work, 31 species had been described from intellectual misappropriation, and lack of scientific the Western Hemisphere. As a consequence of his Publication date: 28 October 2016 urn:lsid:zoobank.org:pub:D4181AC8-66A6-4007-A139-8A2C872803E7 168 HYDROCHIDAE OF MISSISSIPPI study, 50 species were recognized as occurring in rivers and streams. Though there are numerous North America, 28 of which were considered to be small to large man-made impoundments, the state new, and six synonyms were established. While lacks natural lakes aside from oxbows formed the production of the dissertation represented a by the remnants of old river channels. The state significant advancement inHydrochus taxonomy, lies principally within the Gulf-Atlantic Coastal the work was never published. Names ascribed (Eastern) Plain physiographic region of North to new species were unavailable for taxonomic America, with only the extreme northeastern purposes and the synonyms never recognized. corner exhibiting an Appalachian influence. Eleven Some of the new species have been subsequently physiographic regions are represented in the described by others (Smetana 1988; Makhan 1994, state (Figure 1) (Cross et. al. 1974; ESRI 2011; 1995a, 1995b, 1996, 2000, 2001, 2004a, 2004b, Lowe 1915; Mississippi Dept. of Environmental 2005). Several of Hellman’s undescribed species Quality 2013; U.S. Dept. of Commerce 2014), have received numerical designations in keys to and are referenced in our discussions of species Florida (Epler 1996, 2010) and South Carolina distributions. See Testa and Lago (1994) for a (Ciegler 2003) water beetles. Prior to the current more detailed discussion of aquatic habitats and work, Hydrochus comprised 34 described species in descriptions of physiographic regions. the United States and Canada, with 16 occurring in Specimens Examined — The diversity of the southeastern United States. As now configured, aquatic habitats in Mississippi has spawned the genus comprises 31 described species in the equally diverse surveys of aquatic arthropods in United States and Canada, with 16 occurring in the the state, most of which occurred during the past southeastern United States. 40 years. All of these surveys, particularly for The stimulus for this work was a rather large Trichoptera, have involved many hours of light- collection of specimens available through previous trapping throughout the state and the bycatch of research and collecting efforts in and around aquatic specimens from these activities has resulted in habitats throughout Mississippi. Preliminary numerous opportunities to explore portions of our examination of specimens revealed significant fauna not specifically targeted by the collecting problems with available keys and a few obviously activities. Such is the case with Hydrochus. In new species, as well as species fitting some of total, 1,019 specimens were examined during Hellman’s (1975) descriptions. Problems with the this study, including many collected by the work of Makhan were similarly apparent. authors, as well as specimens from University of In this study, our first goal was to validate one Mississippi Insect Collection (UMIC), Auburn new species set forth in Hellman’s dissertation. University Entomology Collection (AUEC), and the Secondly, by examination and imaging of all related Mississippi Entomological Museum (Mississippi type materials, we hope to bring some stability State University, Mississippi, MEM). Holotypes and to Hydrochus taxonomy through verification paratypes were borrowed from the Illinois Natural of species ambiguously described by Makhan. History Survey Insect Collection; the Natural Lastly, we review the Hydrochus found in the state History Museum, London; the Museum of Natural of Mississippi, provide a key to species, record History, Berlin; and Museum of Natural History, available biological data, and note seasonal and Vienna. geographic distributions of the species occurring Photographs were taken using a Leica here. DFC digital camera mounted on a Leica Z16 Macroscope. Images were stacked using Leica MATERIALS AND METHODS Application Suite vs. 4.1 with an Automontage module. All measurements were made using a Wild Study Area — A great diversity of aquatic M5 stereomicroscope with a Wild MMS235 digital habitats occurs within Mississippi, ranging from length measuring set. small to large swamp systems, bogs, seeps, Male genitalia were extracted by placing woodland ponds, flowing springs, and myriad specimens in warm, distilled water for one minute. WORTHINGTON ET AL. 169 Figure 1. Physiographic regions of Mississippi. I= Coastal Meadows, II= Southern Pine Hills, III= Jackson Prairie, IV= Loess Hills, V= Alluvial Plain, VI=North-Central Hills, VII= Flatwoods, VIII= Pontotoc Ridge, IX= Black Prairie, X= Tombigbee-Tennessee River Hills, XI= Paleozoic Bottoms. Insect pins (Size 00) with hooked tips were used elongate in form, with protuberant eyes; antennae to open the pygidium and separate the genitalia with seven antennomeres, three antennomeres distal from the surrounding connective tissue. Genitalia to cupule densely pubescent; maxillary palpi with were preserved in glycerine in polyethylene plastic four palpomeres, labial palpi with three palpomeres; microvials (10 mm long x 4 mm diameter), which pronotum narrowed at base, always narrower than were mounted below specimens on the insect pin. base of elytra. Venter with five visible abdominal The authors would like to stress the importance of sternites, pubescent, apex of fifth visible sternite preserving male genitalia in glycerine rather than with a small non-hydrofuge pubescent plaque, basal applying genitalia to cards using adhesive. Adhesive portion of plaque bearing numerous stout setae in badly distorts the genitalia, and carded genitalia various patterns, terminal portion appearing thin, of all specimens examined during this study were hyaline and smooth. Male genitalia trilobed with removed and stored in glycerine as described above, parameres articulating with a basal piece. Tarsi including those of types. with bisetose empodium. Eggs are laid singly or in groups, all eggs surrounded with a silken sac Family Hydrochidae and cemented