Calopterygoidea, Sélys, 1850

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 : 210-211

Superfamily Calopterygoidea

The superfamily Calopterygoidea , as it is presently understood, is a relatively new assemblage of taxa which has been recognised in recent years through the morphological studies of several authors, such as Rehn (2003) and molecular studies, notably by Dijkstra et al. (2014) and Bybee et al. (2021). One unexpected result of the molecular studies has been the inclusion within the group of the family Argiolestidae , defined by Kalkman & Theischinger (2013). However both molecular studies assess the Calopterygoidea as paraphyletic (Djikstra et al. 2014) or ‘nonmonophyletic’ ( Bybee et al. 2021), but while the former authors left many minor taxa in the category ‘ incertae sedis’, the latter did assign taxa to named families within Calopterygoidea (as ‘Calopterygoidea’ see above). Worldwide it includes 26 families and one incertae sedis group ( Bybee et al. 2021). It is the family arrangement of Bybee et al. (2021) that is followed here. This comprises 11 families in the Oriental realm, and for 10 of them, at least one larva is known. The key is expected to generally be reliable at the family level, with the possible exception of some genera of the weakly defined Rhipidolestidae . Larvae of the newly erected family Priscagrionidae , first recognised in Bybee et al. (2021), remain unknown. Within the region larvae of the large families Calopterygidae (11/12 genera), Euphaeidae (5/8 genera) and Chlorocyphidae (5/16 genera) are unevenly known. The generic divisions of the Chlorocyphidae are not fully resolved, and only small morphological differences have been found between the larvae of even quite distant genera in the family.

Family key Oriental Calopterygoidea :

larva unknown: Priscagrionidae (genera Priscagrion and Sinocnemis )

1 Abdomen with two ventral rows of long fleshy, filamentous gills on S2–8; build generally robust; caudal gills saccoid with terminal filament or blunt process ( Fig. 1 )......................................................... Euphaeidae [absent from Sulawesi]

1’ Abdomen lacking long fleshy gills on venter of abdomen, build very slender to robust, caudal gills of variable form, including saccoid............................................................................................. 2

2 (1’) Antennal scape at least one third total antennal length; antennal sockets set in raised prominence; ( Figs 2, 3 ); very small to large species with long legs; moderately robust to very slender build.................................................. 3

2’ Antennal scape less than one third total antennal length ( Fig. 4 ),................................................ 4

3(2) Prementum with long lateral lobes and often deep median cleft ( Fig. 5 ); antennal scape mostly longer than pedicel and flagellum together ( Fig. 2 ); three well developed caudal gills of variable form; medium to large size............... Calopterygidae

3’ Prementum without long lateral lobes or deep median cleft ( Fig. 6 ); caudal gills reduced to two long, thin lateral spikes, triangular in section, between 0.5–0.9 times length of abdomen, ( Fig. 7 ), vestigial central gill barely apparent as a conical epiproct; build moderately stout, small to very small............................................ Chlorocyphidae

4 (2’). Caudal gills bulbous and sclerotised, either ovate or conical with blunt trifid tips; venter of S10 with paired retractable gill tufts ( Figs 8, 9 ), sometimes just evident as tiny tumescent orifices when retracted; stoutly built............................ 5

4’ Caudal gills not as above, either soft and saccoid, or else laterally or ventrally flattened. Ventral gill tufts on S10 absent.... 6

5(4) Caudal gills subspherical hardened balloons with slight acuminate tip ( Fig. 10 ), antennae normally proportioned with scape ca half length of pedicel; prementum long, narrow and gently tapered................................... Pseudolestidae [endemic to Hainan]

5’ Caudal gills hardened, conical, median tricorn ( Fig. 11 ); first three segments of antennae abnormally thick with scape about twice length of pedicel; prementum broad, squared................................................ Devadattidae [mainland south-east Asia from southern Yunnan and Sundaland]

6 (4’) Caudal gills flattened, foliate and arranged horizontally in a broad fan........................................... 7

6’ Caudal gills either saccoid or broadly flattened and arranged vertically........................................... 8

7(6) Stoutly built with broad, acutely tipped, foliate caudal gills ca 0.6 length of abdomen ( Fig. 12 ); head robust with distinct lateral cephalic lobes; antennae short, no longer than long axis of head from occipital rim to base of labrum; prementum broad and short with short labial palps ( Fig. 13 )...................................................... Mesopodagrionidae [southern China, northern Indochina & Myanmar]

7’ Variable in build but head never with lateral cephalic lobes; antenna moderately long or short, caudal gills always broad and arranged in a horizontal fan, but vary considerably in relative size; Podolestes ( Figs 14, 15 ) may be broadly sympatric with last family but has antennae longer than the long axis of head; caudal lamellae relatively much larger........... Argiolestidae

8(6’) Caudal gills flattened, fleshy short and broad, arranged vertically, median gill thin walled with complex tracheation, ( Figs 18–21 ).................................................................................... Philosinidae [West of Wallace’s line]

8’ Caudal gills saccoid, terminating in filament with median gill placed over two lower, lateral gills...................... 9

9 (8’) Head nearly straight sided behind eyes producing an overall squared profile ( Fig. 24 ); antennae mostly 8 segmented and clearly longer than head from rear occipital margin to base of frons; caudal gills elongate and terminating uniformly in a point ( Fig. 25 ); mature larvae and exuviae huge, 30–40 mm in total length including gills; general build robust but elongate.................................................................................................. Philogangidae

9’ Head with postocular lobes rounded ( Fig. 16 ); antennae short and robust, about same length as head from rear margin to frons; caudal gills ovate saccoid with distinct dorsal ridge and terminating in short, well defined filament; prementum broad and short with short labial palps ( Fig. 17 ); general build stout, tapering caudad and less than 15 mm in length (10–12 mm in recorded specimens).............................................................................. Rhipidolestidae

Figures

FIGURES 1–7. 1. Ventral view of abdomen of Euphaea sp. showing abdominal gills and saccoid gills (original drawing). 2. Head and antennae of Calopterygidae (Neurobasis chinensis) (original drawing). 3. Head and antennae of Chlorocyphidae (Heliocypha biseriata) (original drawing). 4. Antenna of Podolestes orientalis Selys, 1852, scape arrowed (from Choong & Orr 2010). 5. Mask of Calopterygidae (Calopteryx japonica Selys redrawn from Miyakawa 1983). 6. Mask of Chlorocyphidae (Libellago hyalina, from Orr et al. 2024). 7. Habitus of L. hyalina, with detail of right caudal spike (from Orr et al. 2024).

FIGURES 8–11. 8. Pseudolestes mirabilis, ventral view of terminal abdominal segments and caudal gills of showing gill tufts on S10 (after Yu & Bu 2011). 9. Devadatta argyoides, detail of extruded right gill tuft, posterior view (redrawn from Watson 1966). 10. Pseudolestes mirabilis, habitus with detail of mask (after Yu & Bu 2011). 11. Devadatta argyoides, habitus with details of right antenna and mask (original drawing).

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).

FIGURES 18–26. 18. Rhinagrion borneense, habitus (original drawing). 19. Philosina alba, habitus (modified from Zhang et al. 2011). 20. Rhinagrion mima, caudal gills: above heavily tracheated median gill; below right lateral gill with basal spines along mid-rib (modified from Lieftinck 1956). 21. Philosina alba caudal gills: above heavily tracheated median gill; below right lateral gill with basal spines along mid-rib (modified from Zhang et al. 2011) 22. Rhinagrion borneense, detail of mask (original drawing). 23. Philosina buchi, detail of mask (redrawn from Zhang et al. 2011). 24. Philoganga vetusta, habitus (adapted from Xu 2016). 25. Philoganga vetusta, details of caudal gills and antenna (redrawn from Xu 2016). 26. Philoganga montana, detail of mask (original drawing).