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Issue: Vol. 5768 No. 1: 9 Mar. 2026
Type: Article
Published: 2026-03-09
DOI: 10.11646/zootaxa.5768.1.3
Page range: 57-72
Abstract views: 82
PDF downloaded: 22

Larval morphology of Agnoshydrus Biström, Nilsson & Wewalka, 1997: description of A. thailandicus Okada, 2024 and phylogenetic comparison with other known Hyphydrini (Coleoptera: Adephaga, Dytiscidae)

Thailand National History Museum; National Science Museum; Pathum Thani; 12120 Thailand; Coleopterological Society of Japan. National Museum of Nature and Science; Tsukuba; 3050005 Japan
School of Natural Sciences; Laurentian University; Ramsey Lake Road; Sudbury; Ontario; CANADA
University of Buenos Aires; Faculty of Exact and Natural Sciences; Department of Biodiversity and Experimental and Applied Biology (IBBEA); Buenos Aires; Argentina
Coleoptera chaetotaxy Hydradephaga Hydroporinae larval morphology phylogeny Southeast Asia taxonomy

Abstract

The three larval instars of the Thailand endemic Agnoshydrus thailandicus Okada, 2024 are described for the first time, including a detailed chaetotaxy analysis of the cephalic capsule, head appendages, legs, last abdominal segment, and urogomphi. The phylogenetic position of Agnoshydrus Biström, Nilsson & Wewalka, 1997 is studied based on a cladistic analysis of 12 Hyphydrini species (nine genera) and 59 morphological larval characters. Although the phylogenetic relationships of Agnoshydrus within the tribe Hyphydrini remain unresolved, it seems reasonable to suggest a closer relationship with Desmopachria Babington, 1842, Hovahydrus Biström, 1982, and Microdytes J. Balfour-Browne, 1946.

 

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How to Cite

Okada, R., Alarie, Y. & Michat, M.C. (2026) Larval morphology of Agnoshydrus Biström, Nilsson & Wewalka, 1997: description of A. thailandicus Okada, 2024 and phylogenetic comparison with other known Hyphydrini (Coleoptera: Adephaga, Dytiscidae). Zootaxa, 5768 (1), 57–72. https://doi.org/10.11646/zootaxa.5768.1.3