Rhopalum, Stephens, 1829

Saini, Varun & Dey, Debjani, 2022, Description of Rhopalum (s. str.) gulmargense n. sp. with a key to the Indian species of the subgenus Rhopalum Stephens, 1829 s. str. (Hymenoptera: Crabronidae: Crabronini), Zootaxa 5105 (1), pp. 139-144 : 140

Key to the species of subgenus Rhopalum s. str. Stephens from Indian subcontinent

(Males of R. peterseni Tsuneki and R. gulmargense sp. nov. are unknown)

1. Female............................................................................................. 2

- Male............................................................................................... 6

2. Inter-antennal projection indistinct........................................................................ 3

- Inter-antennal projection conspicuous, prominent........................................................... 4

3. Clypeus: medial lobe truncate apically with inconspicuous lateral indentation; antennomere III not longer than wide; admedian line on scutum inconspicuous, mesopleuron smooth; hindtibia inconspicuously swollen apically.. R. croisseti Leclercq, 2011

- Clypeus: anterior margin rounded and slightly notched or broad with conspicuous lateral indentation ( Fig. 4 ); antennomere III as long as or longer than wide; admedian line on scutum distinct; mesopleuron at least with distinct micro punctures; hindtibia different............................................................................................ 5

4. Clypeus: anterior margin minimally indented; inter-antennal tooth more or less truncate, directed downwards; punctation on mesoscutum very fine but clear and relatively dense; narrow yellow stripe on posterior surface of hindtibia, starting from base, not reaching apex; petiole moderately nodose apically.................................... R. avexum Leclercq, 1963

- Clypeus: anterior margin truncate (Fig. 181 of Tsuneki 1976); inter-antennal tooth rounded apically, directed forward (Fig. 182 of Tsuneki 1976); punctation on mesoscutum large; basal ring of hindtibia broad; petiole largely nodose apically (Fig. 184 of Tsuneki 1976)................................................................... R. peterseni Tsuneki, 1976

5. Body length: 6.4 mm; face narrow; anterior margin of clypeus rounded, slightly notched with inconspicuous lateral indentation; inner margin of compound eyes without carina; orbital fovea absent; hindtibia 3 inconspicuously swollen apically; pygidial area narrow at base..................................................................... R. adamsi Leclercq, 2011

- Body length: 7.4−7.6 mm; face broad; clypeus broad, slightly swollen medially, anterior margin dentate with conspicuous lateral indentation ( Fig. 4 ); inner margin of compound eyes with well-defined carina ( Fig. 4 ); orbital fovea indistinct but not absent, elliptical ( Fig. 3 ); hindtibia markedly swollen apically ( Fig. 2 ); pygidial area broader at base ( Fig. 8 )................................................................................... R. gulmargense Saini & Dey , sp. nov.

6. Antennomere VI or VII indented; clypeus free margin not tridentate; pygidial area without lateral border or with well-defined border.............................................................................................. 7

- Antennomere VI and VII not indented; clypeus free margin tridentate; pygidial area bordered laterally but not apically; length 4.2 mm ......................................................................... R. croisseti Leclercq, 2011

7. Clypeus: medial lobe subtruncate; tergum VII without border laterally; length 6 mm ............. R. adamsi Leclercq, 2011

- Clypeus: median lobe rounded apically; tergum VII forming flat pygidial area, with well-defined border; length 6.5 mm ................................................................................... R. avexum Leclercq, 1963

Figures

FIGURES 1−8. Rhopalum (Rhopalum) gulmargense Saini & Dey, sp. nov. Holotype ♀. 1. Label; 2. Habitus, lateral view; 3. Head and thorax, dorsal view; 4. Head, frontal view; 5. Thorax, lateral view; 6. Propodeum, dorsal view; 7. Metasoma, lateral view; 8. Pygidium, dorsal view.