Argiolestidae, Fraser, 1960

Orr, Albert G. W., 2024, A review of present knowledge of larvae of the Calopterygoidea (Zygoptera) of the Oriental realm, including keys to families and known genera, Zootaxa 5497 (2), pp. 209-243 : 223

Family Argiolestidae

Just four genera and 15 species of this mainly Australian and Oceanian realm (sensu Holt et al. 2013) family occur in the Oriental realm, and only one genus, Podolestes (9 spp.), occurs on the Asian mainland ( Kalkman & Theischinger 2013). The larva is known and described only for P. orientalis Selys ( Choong & Orr 2010), but other species of the genus are probably similar. Based on their well-known Australian relatives all argiolestids are believed to possess broad, rounded or foliate caudal gills arranged in a horizontal fan, and most are of moderately stout build. Podolestes ( Fig. 14 ), is known west of Sulawesi and the Philippines and in eastern mainland Asia where it might be broadly sympatric with species of Mesopodagrionidae which argiolestid larvae most resemble. However, Podolestes larvae have much larger gill lamellae, a different head shape and finer, longer antennae; the prementum is long and narrow, expanded anteriorly with almost no median lobe ( Fig. 15 ). They inhabit pools in lowland swamp forest, as opposed to swift upland streams. Even in situations where the adults are abundant, the larvae can be very difficult to locate, but they have been discovered among leaf litter in shallow forest pools and in bankside root masses in very slowly flowing streams. According to Ngiam & Ng (2022) the larva “Hunts among fallen leaf packs at shallow edges of forest pools, with abdomen raised and gills aimed at the surface, possibly to maximise oxygen uptake in poorly oxygenated pools”.

Larva unknown: Argiolestes (1 sp.), Celebargiolestes (4 spp.), Luzonargiolestes (2 spp.)

Figures

FIGURES 12–17. 12. Mesopodagrion tibetanum, habitus with detail of right profile of head (based on Yu 2016). 13. M. tibetanum, detail of mask (redrawn from Yu 2016). 14. Podolestes orientalis, habitus (from Choong & Orr 2010). 15. Podolestes orientalis, detail of mask (from Choong & Orr 2010). 16. Rhipidolestes aculeatus, habitus and detail of lateral and median gill (modified from Asahina 1994). 17. Rhipidolestes aculeatus, detail of mask (modified from Ishida 1996).