Leptanillinae Emery, 1910, 1870

Griebenow, Zachary, 2024, Systematic revision of the ant subfamily Leptanillinae (Hymenoptera, Formicidae), ZooKeys 1189, pp. 83-184 : 83

Leptanillinae Emery, 1910

Type genus.

Leptanilla Emery, 1870: 196.

Worker diagnosis

(modified from Bolton 2003):

Mandibles without differentiated basal and masticatory margins.

At least one preapical tooth or lobe present on mandible.

Frontal lobes absent.

Antennal sockets dorsal, fully exposed.

Compound eyes absent, if present ( Protanilla izanagi Terayama, 2013) then reduced to two ommatidia (Fig. 17A ).

Ocelli absent.

Antenna 12-merous.

Promesonotal suture fully articulated.

Propodeal lobes weakly present (Opamyrmini) or absent (Leptanillini).

Propodeal spiracle situated low on propodeum.

Metacoxal foramen small, fully closed (Fig. 18 ).

Suture absent from annulus surrounding metacoxal foramen.

Metapleural gland present.

Orifice of metapleural gland covered by dorsal cuticular flange.

Helcial sternite reduced and partly covered by corresponding tergite.

Spiracle of abdominal segment III large and placed far forward.

Spiracles of abdominal segments IV-VII concealed by posterior margins of preceding tergites.

Petiole sessile, rarely subsessile ( Protanilla taylori species group).

Abdominal postsclerites II with (Leptanillini) or without (Opamyrmini) complete tergosternal fusion.

Abdominal postsclerites III with (Leptanillini) or without (Opamyrmini) tergosternal fusion.

Abdominal segment III petiolate (Leptanillini) or not (Opamyrmini).

Abdominal segment IV without tergosternal fusion.

Stridulitrum absent from abdominal segment IV.

Abdominal tergite VII large, with simple posterior margin.

Sting present.

Pretarsal claws edentate.

Gyne diagnosis.

As above, but alate or dichthadiiform (rarely ergatoid). If alate then with ocelli and pterostigma; hindwing with R + Rs and 1A tubular, not intersecting distal wing margin. If dichthadiiform then compound eyes reduced to one or two ommatidia, or absent; ocelli absent; mandibles sometimes edentate.

Male diagnosis

(modified from Boudinot 2015):

Mandible edentate, nub-like or spatulate ( Leptanilla anomala (Brues, 1925), comb. nov.).

Frontal carinae absent.

Cuticular pegs absent from anterior clypeal margin.

Antenna 13-merous.

Funiculus filiform to submoniliform.

Oblique mesopleural sulcus present or absent.

Metapleural spiracular plate absent.

Propodeal lobes inconspicuous or absent.

Metacoxal foramen small, fully closed.

Mesotibia with one or two spurs or none.

Metatibia with one or two spurs.

Metatarsus lacking posterolateral line of dense differentiated setae.

Pretarsal claws edentate.

Pterostigma present or absent.

Rs+M absent (Leptanillini) or present, nebulous (Opamyrmini).

1m-cu absent (Leptanillini) or present, nebulous (Opamyrmini).

Jugal lobe absent.

Hindwing venation reduced, at most R+Rs and 1A tubular.

Metapleural gland absent (Fig. 19A ) or rarely present (Fig. 19B ) (e.g., Leptanilla zhg-th02).

Petiole present or reduced to absent ( Leptanilla thai species group, Leptanilla havilandi species group).

Helcium axial or infra-axial.

Abdominal segment III not petiolate, or rarely petiolate ( Protanilla bicolor species group).

Abdominal segment IV not vaulted, as long as, or distinctly longer than posterad abdominal segments.

Abdominal spiracles IV-VIII obscured by preceding tergites.

Posterior margin of abdominal sternite IX with posteromedian process, or entire, or emarginate, or with mulceators.

Cerci absent.

Larval diagnosis.

Stenocephalous, with post-cranial soma moderately (i.e., habitus pogonomyrmecoid) to extremely (i.e., habitus leptanilloid) elongate. Mandibles typhlomyrmecoid or leptanilloid.

Figures

Figure 17. Aspects of Protanilla izanagi, worker A profile view of posterior half of cranium B ventral view of the mandibles. Abbreviation: com = compound eye. Scale bars: 0.1 mm (A); 0.2 mm (B).

Figure 18. Metacoxal foramen of Leptanilla havilandi (CASENT 0010809), ventral view, worker. Scale bar: 0.05 mm.

Figure 19. Metapleuron in male Leptanillinae A Leptanilla nr. indica (CASENT 0106381) B Leptanilla zhg-th 02 (CASENT 0842615). Abbreviation: mpl = metapleural gland orifice. Scale bars: 0.05 mm.