Zootaxa 4646 (3): 401–433 ISSN 1175-5326 (print edition) https://www.mapress.com/j/zt/ Article ZOOTAXA Copyright © 2019 Magnolia Press ISSN 1175-5334 (online edition) https://doi.org/10.11646/zootaxa.4646.3.1 http://zoobank.org/urn:lsid:zoobank.org:pub:D9362795-F949-4A1F-9E46-1A466EDD9301 Description of the larvae of four Japanese Platambus Thomson, 1859 (Coleoptera: Dytiscidae: Agabinae) with phylogenetic considerations RYOHEI OKADA1, YVES ALARIE2 & MARIANO C. MICHAT3 1Coleopterological Society of Japan. National Museum of Nature and Science, Tsukuba, 3050005 Japan. E–mail:
[email protected] 2Department of Biology, Laurentian University, Ramsey Lake Road, P3E 2C6, Canada. E-mail:
[email protected] 3Laboratory of Entomology, IBBEA, CONICET-UBA., DBBE-FCEN, University of Buenos Aires, Argentina. E-mail:
[email protected] Abstract The larvae of four species of Platambus Thomson, 1859 from Japan, P. pictipennis (Sharp, 1873), P. convexus Okada, 2011, P. fimbriatus (Sharp, 1884) and P. sawadai (Kamiya, 1932) are described for the first time including a detailed chaetotaxy analysis of the cephalic capsule, head appendages, legs, last abdominal segment and urogomphi. A provisional parsimony analysis based on 39 informative larval characteristics of 15 species in seven genera of the subfamily Agabinae was conducted using the program TNT. Larvae of the Platambus species studied stand out from those of other genera of Agabinae by the unique presence of a subquadrate last abdominal segment not protruding posteriorly into siphon and the much shorter length of the primary urogomphal seta UR5 compared to seta UR7 in first instar larva. Key words: Coleoptera, Dytiscidae, Agabinae, Platambus, chaetotaxy, larvae, Palearctic Introduction The dytiscid genus Platambus Thomson, 1859 contains 67 species distributed in the Nearctic, Neotropical, Orien- tal and Palearctic regions (Bian & Ji 2008; Hendrich & Przewoźny 2015; Hájek & Zhang 2019; Nilsson & Hájek 2019).