Leptomyrmex aitchisoni, Smith, Derek J. & Shattuck, Steve, 2009

Smith, Derek J. & Shattuck, Steve, 2009, Six new, unusually small ants of the genus Leptomyrmex (Hymenoptera: Formicidae), Zootaxa 2142 (1), pp. 57-68 : 59

Leptomyrmex aitchisoni sp. n.

( Figs 1–3 , 19–21 )

Types. Holotype worker from Doubleduke State Forest, MacFaydens Rd., 1.2km East of junction with Range Rd. , 29°13’18”S 153°13’23”E, New South Wales, 4 Feb.-9 Apr. 1993, M.Grey & G.Cassis. ( AMSA: K 167550 ); four paratype workers, same data as holotype ( AMSA: K.167551, K.167552, K.167553, K.167554).

Diagnosis. Head relatively elongate (CI less than 79, Fig. 19 ); antennal scape relatively long (SI> 170, Fig. 20 ) and extending beyond the vertex of the head by greater than half their length; pilosity short adpressed hairs; palps relatively short, failing to reach the posterior of the head capsule.

Worker description. Vertex of head flat to weakly concave, corners rounded, sides of head almost straight, head widest at the midlength. Scape long, surpassing the vertex by distinctly more than half their length. Medial hypostoma distinctly notched. Palps relatively short, extending about ¾ of the length of the head capsule, formula 6:4. Mesonotum without a raised anterior region, propodeum with short dorsum. Legs long. Hind tibial spurs with reduced barbules (barbules shorter than the width of the shaft), absent from basal ¼. Scale present, ridged with a distinct angle dorsally, in profile moderately angular, strongly inclined anteriorly, anterior and posterior faces about equal in length. Head, mandibles and mesosoma uniformly light to dark brown in colour, legs and antennae paler, gaster darker.

Measurements. Worker (n = 63) - CI 65–74; EL 0.17–0.25; HL 0.79–0.96; HW 0.56–0.65; MTL 0.71–1.08; SI 197–216; SL 1.12–1.32; WL 1.20–1.58.

Additional material examined. New South Wales: 2.8km from Wheatley Creek access road (on camp ck.) (Cassis,G. & Grey,M.) ( AMSA) ; Beaury State Forest, northwards along Wallaby Creek Rd (Cassis,G. & Grey,M.) ( AMSA) ; Boorook S.F., 300m NW of Gilgurry Mt. (Grey,M. & Cassis,G.) ( ANIC) ; Boorook SF, Colonga Rd. crossing of Boorook Ck . (Cassis,G. & Grey,M.) ( AMSA) ; Boorook SF, Midway between Boorook Ck. and Gilgurry Ck. on Conlongan Rd. 1km NW of Boorook Ck. Junction (Cassis,G. & Grey,M.) ( AMSA) ; Boorook SF, near Boonoo Boonoo Falls (Cassis,G. & Grey,M.) ( AMSA) ; Doubleduke SF, junction of Range and Lockleys Rds (Cassis,G. & Grey,M.) ( AMSA) ; Doubleduke SF, Range Rd. , 1.5km west of junction with Lockleys Rd (Cassis,G. & Grey,M.) ( AMSA) ; Enfield SF, Mummel Forest Rd., 8.8km N of junction with Enfield Forest Rd (Cassis,G. & Grey,M.) ( AMSA) ; Gibralter Range N.P., Sugarloaf Pt. 29°26’S 152°23’E (P.S.Ward) ( ANIC) ; Gilgurry SF, Rivertree Fire Trail , on ridge approx. 2km NNE from turnoff (Cassis,G. & Grey,M.) ( AMSA) ; Madmans Creek Flora Reserve, Madman’s Ck. , 200m upstream from bridge on Murphy’s Rd (Cassis,G. & Grey,M.) ( AMSA) ; Oakwood SF, 300m along Sydney Plain Hut Track from London bridge Fire Trail (Cassis,G. & Grey,M.) ( AMSA) ; Ramornie S.F., track off T-Ridge Rd. (Grey,M. & Cassis,G.) ( AMSA, ANIC) ; Sugarloaf Point , Gibraltar Range Natl. Pk. (Ward,P.S.) ( ANIC) ; Washpool N.P., NW Fire Trail (Cassis,G. & Grey,M.) ( AMSA) ; Washpool National Park, Grassy Ck. , where crossed by NW Fire Trail / Washpool Trail (Cassis,G. & Grey,M.) ( AMSA) ; Whian Whian SF, Running Rd. , 150m ” E of Nightcap Range Rd (Cassis,G. & Grey,M.) ( AMSA) . Queensland: Crows Nest Nat. Park , Perseverance Section (QM Party) ( QMBA) .

Comments. This is a relatively common and widespread species in north-eastern NSW and south-eastern Queensland. It is found in a range of forest habitats from wet sclerophyll to rainforest, where it nests under stones. It is readily separated from the sympatric species L. burwelli and L. ramorniensis as noted in the key. This species has been named after Mr. Ron Aitchison. Mr. Ray Huetter sponsored this patronymic through the Australian Museum’s Immortals Project.

Figures

FIGURES 1–6. Leptomyrmex aitchisoni sp. n. worker. Fig. 1, front of head; Fig. 2, lateral view of body; Fig. 3, dorsal view of body. Leptomyrmex burwelli sp. n. paratype worker. Fig. 4, front of head; Fig. 5, lateral view of body; Fig. 6, dorsal view of body.

FIGURES 19–20. Fig. 19, graph of head length versus head width. Fig. 20, graph of scape length versus head width.

FIGURES 21–22. Distribution of material examined during this study. Fig. 21, L. aitchisoni (triangle), L. burwelli (circle) and L. ramorniensis (square). Fig. 22, L. dolichoscapus (circle), L. garretti (triangle) and L. pilosus (square). Note the restricted range of most species, especially the set in Fig. 22, where all species are essentially sympatric.