Kilariodes, Sartori & Derleth, 2010

Sartori, Michel & Derleth, Pascale, 2010, The dipterous Leptophlebiidae of Borneo (Insecta, Ephemeroptera), Zootaxa 2490, pp. 33-39 : 35-36

Kilariodes gen. nov.

Type species: Kilariodes marifae sp. nov. by present designation

Nymph. Head prognathous. Clypeus well developed ( Fig. 19) as broad as the labrum. Labrum ( Figs 7, 19) with lateral margin rounded and distal margin clearly cordiform; anteromedian emargination well marked ( Fig. 8). Left and right mandibles similar ( Figs 9–10); outer margin very angular with a hump in the middle. Maxillae ( Fig. 11) stout and robust; palp 3-segmented; inner apical angle of the galea ( Fig. 13) with one comb-shaped dentiseta, no subapical row of setae. Hypopharynx ( Fig. 14) with superlinguae well developed laterally and rounded; lingua with lateral processes well developed and rounded at apex. Labium ( Fig. 15) with palp 3-segmented, glossae small and rounded apically, paraglossae large, rounded laterally and inner margin slightly pointed. Metathoracic wing pads missing. Legs ( Fig. 16) with stout femora, ca 2 times longer than wide; claw ( Fig. 17) moderately hooked, with a single row of denticles, the proximal smaller than the others. Gills present on segments I–VII, similar in shape, and each composed of a dorsal and a ventral very long, slender and unbranched lamella. No posterolateral projections on segments II– V, slightly marked on segments VI –IX.

Male and female adults unknown.

Etymology. The genus name is an arbitrary combination of letter to honour Jean-Christophe “Kil” Decker (Pully, Switzerland), great friend of us, with reference to the Latin adjective hilaris meaning joyful. The gender is feminine.

Distribution. Island of Borneo (East Kalimantan, Indonesia)

Affinities. Kilariodes possesses most of the characters listed by Kluge (1994) to define members of the subfamily Atalophlebiinae : hypopharynx with superlinguae laterally developed ( Fig. 14), dorsal surface of labrum with a well defined row of setae ( Fig. 7), galea with the proximal dentiseta comb-shaped ( Fig. 13). Kilariodes has few affinities with Dipterophlebiodes which is a member of Leptophlebiinae . The new genus presents some similarities with Isca (shape of labrum, hypopharynx or even labium), but is easily separated by the shape of the mandibles, the body size and the gills in lateral position. Kilariodes presents some affinities with Hagenulodes Ulmer, 1920 , an endemic genus of Seychelles. It shares with it the lack of posterior wing pads, and to some extent, the shape of the mandibles, the hypopharynx and the tarsal claw, but it can be easily separated by the shape of the gills ( Peters & Edmunds 1970). The combination of the following characters is therefore unique and defines the new genus: (1) presence of a hump on the outer margin of mandibles, (2) labrum with a wide anteromedian emargination, (3) maxilla without subapical row of setae, (4) hindwing pads missing, (5) gills slender with two long and unbranched lamellae.

It could be argued that Kilariodes represents in fact the larval stage of either the genus Sulu Grant & Peters or Simothraulus Ulmer , but according to Grant & Peters (1993), both genera belong to the Thraulus lineage, which possesses gills completely different from those of Kilariodes . A more complete assignment of the phylogenetic position of Kilariodes will be possible when the adult stages will be known.