Brychius

Abstract: Selected external characters of adult representatives of all haliplid genera (Algophilus Zimmermann, Apteraliplus Chandler, Brychius Thomson, Haliplus Latreille, and Peltodytes Regimbart) were examined and analyzed phylogenetically. Small, subulate ultimate segments of the maxillary and labial palps, strongly reduced elytral suturai striae, distinctly asymmetrical parameres, and endophytic deposition of eggs are synapomorphies of Haliplidae excluding Peltodytes. The laterally compressed peristome, resulting in a peculiar shape and arrangement of mouthparts, extremely shallow maxillary fossae, and very large metacoxal plates which cover all but the last abdominal sternites are synapomorphies of Peltodytes. Complete absence of elytral suturai striae, reduction in length of elytral epipleurae, serrate meso‐ and metatibial spurs, transverse bulges on sterna V‐VII, elongate gonocoxosternal processes (Algophilus?) reduction of the fringe of setae of the left paramere are synapomorphic characters of a monophylet...

Abstract: The Nearctic species of Brychius Thomson, 1859 (Coleoptera: Haliplidae) were revised by examining adult and larval specimens. Brychius albertanus Carr 1928 is a junior subjective synonym of Brychius hornii Crotch 1873. Descriptions of adults and larvae (excluding B. pacificus), distribution data, and a key to adults are provided for all Nearctic species. From a reconstructed phylogeny of all species of Brychius, B. hornii + B. hungerfordi is the sister-group to Brychius elevatus Panzer 1794 + Brychius glabratus Villa 1833; and these combined are the sister group to Brychius pacificus Carr, 1928. Species of Brychius are hypothesized to have arisen and diversified on Laurasia during the Jurassic Period. Brychius hornii and B. hungerfordi originated in the Tertiary Period before the formation of the Rocky Mountains, ca. 50 to 100 million years ago. It is thought that vicariance has played an important role in the present distribution, where species were once widespread in cool mountainous glacial st...

Abstract: We use carbon and nitrogen isotope data to elucidate the diets of larval and adult Brychius hungerfordi Spangler in streams in Northern Lower Michigan. Diet analysis suggests that feeding behavior during the larval life stage is different from that of the adult. Larvae appear to prefer the alga Dichotomosiphon tuberosus (Braun) Ernst. Adults appear to be generalists, feeding on Dichotomosiphon, Cladophora Kuetzing and Chara Linnaeus as well as the epiphytic diatom Cocconeis Ehrenberg. Dichotomosiphon, although widespread, is not common. Its presence may be an important factor in determining the distribution of the Federally endangered beetle.