Lithurgini, Newman

Gonzalez, Victor H., Engel, Michael S. & Griswold, Terry L., 2013, The lithurgine bees of Australia (Hymenoptera: Megachilidae), with a note on Megachile rotundipennis, Journal of Melittology 2013 (11), pp. 1-19 : 14-15

Key to the genera of Lithurgini

(Modified from Michener, 2007)

1. Labrum longer than clypeus, often much longer; metatibia of female rather uniformly setose on outer, anterior, and posterior surfaces, spicules relatively inconspicuous among setae; lower mandibular tooth longer than middle tooth, or, in some females, lower and middle teeth equal (South America) ......... ..................................................................................................... Trichothurgus Moure

—. Labrum about as long as clypeus; metatibia of female with setae of broad, longitudinal outer zone shorter and sparser than those of anterior and posterior surfaces, spicules large and conspicuous in outer zone; lower mandibular tooth conspicuously shorter than middle tooth, which is longest mandibular tooth .... 2

2(1). Body small, slender, hoplitiform; pretarsal claws of female cleft; pterostigma of moderate size, broadest at base of vein r-rs, sides converging toward base; maxillary palpi dimerous (two-segmented) (South America) ................................ ................................................................................................... Microthurge Michener

—. Body broad, megachiliform; pretarsal claws of female simple; pterostigma small, sides basal to vein r-rs parallel or nearly so [in some small species of Lithurgus the pterostigma is larger, approaching the size of that of Microthurge ]; maxillary palpi trimerous or tetramerous (three- or four-segmented) ....................... 3

3(2) Males ............................................................................................................................ 4

—. Females ........................................................................................................................ 6

4(3) Arolia absent or rudimentary ..................................................... Lithurgus Berthold

—. Arolia present ............................................................................................................. 5

5(4) Metabasitarsus without distinct projections, carina or protuberance on inner surface, at most with small, smooth, shiny, asetose area distally; outer metatibial spur stout, strongly bent apically; first flagellomere short, not or little longer than broad, at most slightly longer than second, which is at most slightly longer than broad (Western Hemisphere) ................... Lithurgopsis Fox

—. Metabasitarsus with distinct carina on asetose inner surface ( Figs. 5 , 10 , 15 ); outer metatibial spur slender, straight or scarcely bent apically; first flagellomere long, more than 1.5 times longer than broad, nearly twice as long as second, which is much broader than long; Australian mainland ................................................... Austrothurgus Gonzalez & Engel , n. gen.

6(3) Outer metatibial spur stout, strongly bent apically; first flagellomere short, not or little longer than broad, at most slightly longer than second, which is at most slightly longer than broad; facial prominence of female entirely supraclypeal (absent in one species); Western Hemisphere ......................................................................................... Lithurgopsis Fox

—. Outer metatibial spur slender, straight or scarcely bent apically; first flagellomere long, more than 1.5 times longer than broad, nearly twice as long as second, which is much broader than long (except in one undetermined species from India); facial prominence of female involving base of clypeus and sometimes part of supraclypeal area ..................................................... 7

7(6). Facial prominence involving base of clypeus and part of supraclypeal area ( Figs. 18 , 24 ); widespread including Australia...................... Lithurgus Berthold

—. Facial prominence mostly involving base of clypeus ( Figs. 4 , 7 ); Australian mainland ................................................... Austrothurgus Gonzalez & Engel , n. gen.

Figures

Figures 1–5. Photomicrographs of lectotype female (1–4) and male (5) of Austrothurgus rubricatus (Smith). 1. Lateral habitus. 2. Dorsal habitus. 3. Lateral view of head. 4. Facial view. 5. Male metatarsus, depicting modification of metabasitarsus.

Figures 6–10. Photomicrographs of lectotype female (6–9) and male (10) of Austrothurgus cognatus (Smith). 6. Lateral habitus. 7. Facial view. 8. Lateral view of head. 7. Detail of vertex. 10. Male metatarsus (apex missing), depicting modification of metabasitarsus.

Figures 13–16. Photomicrographs of holotype male of Austrothurgus malgaru, new species. 13. Facial view. 14. Detail of sculpturing on mesoscutum and mesoscutellum. 15. Metatarsus, depicting modification of metabasitarsus. 16. Apex of metasoma.

Figures 17–19. Photomicrographs of holotype female of Lithurgus andrewsi Cockerell. 17. Lateral habitus. 18. Facial view. 19. Detail of vertex.

Figures 23–24. Photomicrographs of lectotype female of Lithurgus atratus Smith. 23. Lateral habitus. 24. Facial view.