ZooKeys 966: 57–151 (2020) A peer-reviewed open-access journal doi: 10.3897/zookeys.966.55192 RESEARCH ARTICLE https://zookeys.pensoft.net Launched to accelerate biodiversity research The Dolichopodidae (Diptera) of Montserrat, West Indies Justin B. Runyon1,2 1 Rocky Mountain Research Station, USDA Forest Service, 1648 S. 7th Avenue, Bozeman, Montana 59717, USA 2 Montana Entomology Collection, Montana State University, Room 50 Marsh Laboratory, Bozeman, Montana 59717, USA Corresponding author: Justin B. Runyon ([email protected]) Academic editor: Marija Ivković | Received 6 June 2020 | Accepted 4 August 2020 | Published 9 September 2020 http://zoobank.org/B18DEB58-2C8F-4F95-B7EF-3BECC9F4D4B7 Citation: Runyon JB (2020) The Dolichopodidae (Diptera) of Montserrat, West Indies. ZooKeys 966: 57–151. https://doi.org/10.3897/zookeys.966.55192 Abstract The long-legged flies (Dolichopodidae) of the island of Montserrat in the Lesser Antilles have been sur- veyed and include 63 species in 27 genera. The following eleven new species are described and illustrated: Amblypsilopus marskeae sp. nov., Medetera iviei sp. nov., Medetera montserratensis sp. nov., Systenus ladon- nae sp. nov., Thrypticus mediofuscus sp. nov., Chrysotus antillensis sp. nov., Chrysotus callichromoides sp. nov., Chrysotus interfrons sp. nov., Chrysotus montserratensis sp. nov., Diaphorus robinsoni sp. nov., and Sympycnus montserratensis sp. nov. Six species have only been found on Montserrat (ca. 10% endemic- ity). Keys are provided to the genera and species on Montserrat, their known distribution summarized, and additional new island records provided for many species. Asyndetus wirthi Robinson is synonymized with A. interruptus (Loew) and Achradocera apicalis (Aldrich) is removed from synonymy with A. barbata (Loew). Diaphorus flavipesAldrich is transferred to Chrysotus as a new combination. A new replacement name, Chrysotus milvadu nom. nov., is provided for the Nearctic Chrysotus parvulus Van Duzee. Lecto- types are designated for Achradocera apicalis (Aldrich) and Asyndetus fratellus Aldrich. The fauna of Mont- serrat is summarized and compared with that of Dominica. Collecting methods are compared and threats to the dolichopodid fauna of Montserrat discussed. Keywords Biodiversity, Caribbean, checklist, inventory, Lesser Antilles, new species, West Indies Copyright Justin B. Runyon. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. 58 Justin B. Runyon / ZooKeys 966: 57–151 (2020) Table of contents Introduction ........................................................................................................... 61 Materials and methods ........................................................................................... 64 Results .................................................................................................................... 65 Key to the genera of Dolichopodidae of Montserrat ........................................... 68 Systematic List ................................................................................................... 72 Subfamily Parathalassiinae .............................................................................. 72 Genus Chimerothalassius Shamshev & Grootaert ............................................ 72 Chimerothalassius runyoni Brooks & Cumming .......................................... 72 Subfamily Sciapodinae ................................................................................... 72 Genus Amblypsilopus Bigot ............................................................................. 72 Key to the species of Amblypsilopus in Montserrat .......................................... 72 Amblypsilopus luteus (Robinson) ................................................................. 72 Amblypsilopus marskeae sp. nov. .................................................................. 73 Genus Condylostylus Bigot .............................................................................. 76 Key to the species of Condylostylus in Montserrat ............................................ 76 Condylostylus albiciliatus (Van Duzee) ......................................................... 77 Condylostylus longicornis (Fabricius) ............................................................ 78 Condylostylus nigripilosus Robinson ............................................................. 78 Condylostylus quadricolor (Walker) .............................................................. 79 Subfamily Neurigoninae................................................................................. 79 Genus Coeloglutus Aldrich .............................................................................. 79 Coeloglutus concavus Aldrich ....................................................................... 79 Genus Dactylomyia Loew ............................................................................... 80 Dactylomyia decora (Aldrich) ...................................................................... 80 Genus Neurigona Rondani ............................................................................. 80 Neurigona fuscicosta Robinson .................................................................... 80 Genus Viridigona Naglis ................................................................................. 80 Viridigona thoracica (Van Duzee) ............................................................... 80 Subfamily Medeterinae .................................................................................. 81 Genus Cryptopygiella Robinson ...................................................................... 81 Cryptopygiella musaphila Robinson ............................................................. 81 Genus Medetera Fischer von Waldheim .......................................................... 82 Key to the species of Medetera in Montserrat .................................................. 82 Medetera crassicauda Robinson ................................................................... 82 Medetera dominicensis Robinson ................................................................. 83 Medetera iviei sp. nov. ................................................................................ 84 Medetera montserratensis sp. nov. ................................................................. 87 Medetera pseudonigripes Robinson............................................................... 92 Genus Systenus Loew ...................................................................................... 92 Systenus ladonnae sp. nov. ........................................................................... 92 The Dolichopodidae (Diptera) of Montserrat, West Indies 59 Genus Thrypticus Gerstäcker ........................................................................... 95 Key to the species of Thrypticus in Montserrat ................................................ 95 Thrypticus abdominalis (Say) ....................................................................... 96 Thrypticus aequalisRobinson ...................................................................... 96 Thrypticus mediofuscus sp. nov. .................................................................... 96 Thrypticus parvulusVan Duzee ................................................................... 99 Thrypticus violaceusVan Duzee ................................................................... 99 Subfamily Achalcinae ................................................................................... 100 Genus Xanthina Aldrich ............................................................................... 100 Xanthina rubromarginata Robinson .......................................................... 100 Subfamily Enliniinae .................................................................................... 100 Genus Enlinia Aldrich .................................................................................. 100 Enlinia patellitarsis Robinson ................................................................... 100 Genus Harmstonia Robinson ........................................................................ 101 Harmstonia simplex Robinson ................................................................... 101 Subfamily Peloropeodinae ............................................................................ 101 Genus Micromorphus Mik ............................................................................ 101 Micromorphus albipes (Zetterstedt) ........................................................... 101 Genus Peloropeodes Wheeler ......................................................................... 102 Peloropeodes frater (Aldrich) ...................................................................... 102 Subfamily Diaphorinae ................................................................................ 102 Genus Achradocera Becker ............................................................................ 102 Achradocera apicalis (Aldrich) ................................................................... 102 Genus Asyndetus Loew.................................................................................. 104 Key to the species of Asyndetus in Montserrat ............................................... 104 Asyndetus interruptus (Loew) ...................................................................