Lordomyrma tortuosa (Mann)

Sarnat, E. M., 2006, Lordomyrma (Hymenoptera: Formicidae) of the Fiji Islands., Bishop Museum Occasional Papers 90, pp. 9-42 : 33-34

Lordomyrma tortuosa (Mann)

(Figs. 18, 19)

Rogeria tortuosa Mann , 1921: 452, fig 18.

Description. Worker. TL 4.15-4.53, HL 0.93-1.01, HW 0.82-0.90, CI 0.87-0.91, SI 0.69-0.76, REL 0.18-0.24, PSLI 0.96-1.11, MFLI 0.94-1.02, DPWI 1.00-1.11 (10 measured).

A large-sized shiny, reddish brown species with massive promesonotum, modestly-sized straight propodeal spines and strong arcuate carinae on face. In full face view, posterior margin of head evenly convex with gently rounded corners. Clypeus bearing one pair of weak carinae. Frontal carinae strong, becoming confluent with series of arcuate carinae present between eye and posterior corners of head, forming dorsal margin of a broad, poorly defined scrobe. Eyes of moderate size. In profile, shape of promesonotum massive, strongly convex, and bulging above the head and propodeum. Propodeal spines strong, triangular, straight, divergent; in profile when measured from propodeal spiracle roughly equal to the width of the procoxae. Propodeal lobes of moderate size, triangular, stout. Petiole robustly built; anterior face strongly sloped and weakly concave; dorsal face more gently sloping and weakly convex; the rounded apex occurring at the anterior angle. Postpetiole with anterior and dorsal faces evenly convex, apex occurring at midline. Mandibles smooth and shining with scattered setigerous foveolae. Middorsum of head smooth and shining with scattered foveolae; several carinae mesad of frontal carinae, extending continuously or with interruptions from frontal lobes posteriorly to behind the eyes. Frontal lobes with one pair of strong carinae in addition to the frontal carinae. In oblique lateral view, widely separated and strongly elevated arcuate carinae overlaying all dorsal surfaces of head from frontal carinae to ventrolateral carina and from posterior corners to antennal insertions. Promesonotum smooth and shining with scattered foveolae. Procoxae smooth and shining. Sides of mesonotum, metapleuron, and propodeum overlain by coarse, widelyspaced and occasionally intersecting rugae. In dorsal view, dorsal face of propodeum smooth and shining, the anterior margin without a transverse carina posterior to metanotal groove; declivitous face smooth and shining. Petiole with smooth and shining anterior face, banded by coarse transverse rugae that reach the ventral face. Postpetiole coarsely rugoreticulate. Gaster smooth and shining. All dorsal surfaces with an abundance of suberect to erect acuminate hairs, the longest of which equal or exceed the length of the eye. Head, mesosoma and gaster reddish brown with lighter appendages.

Type Material. Syntypes, workers, Ovalau, Fiji (W.M. Mann) (MCZC, NMNH).

Other Material Examined. FIJI: Kadavu: Mt. Washington, 1.4 km SSW Lomaji Village, 19°07'06"S 177°59'25"E, 700 m, 5.ix.2006, ground foraging (E.M. Sarnat #2406). Koro: Mt. Kuitarua, 2.7 km NW Nasau Village, 17°17'41"S 179°24'39"E, 465m, 12.iii.2005, in leaf litter (E.M. Sarnat #1861, #1862.08); Mt. Kuitarua, 3 km WNW Nasau Village, 17°17'42"S 179°24'30"E, 420 m, 13.iii.2005, nesting in large wet log (E.M. Sarnat #1885); Mt. Kuitarua, 3.1 km WNW Nasau Village, 17°17'43"S 179°26'11"E, 440 m, 20.vi.2005, in dead tree fern (E.M. Sarnat #2100); Mt. Kuitarua, 3.7km NW Nasau Village, 17°17'27"S 179°24'11"E, 470 m, 20.vi.2005, on log (E.M. Sarnat #2086.01, #2086.02); Mt. Nabukala, 4.7 km WSW Nasau Village, 17°18'44"S 179°23'26"E, 500 m, 15.iii.2005, foraging under bark of fallen tree (E.M. Sarnat #1897). Taveuni: Road to Des Voeux [Devo] Peak, 16°50'S 179°59'W, 700 m, 26.iv.1997 (L.S. Farley); Tavoro Falls, 1.4km WSW Korovou Village 16°49'47"S 179°53'23"W, 100 m, 18.vi.2005, foraging on stone (E.M. Sarnat #2053 & J.A. Schreiber); Tavoro Falls, 2 km WSW Korovou Village, 16°49'47"S 179°53'23"W, 160 m, 18.vi.2005 (E.M. Sarnat #2061, #2064.02, #2066.02). Viti Levu: 5.5 km NNW Nadakuni Village, 17°55'S 178°16'E, 300 m, 7.v.2003, sifted litter (A. Tabutabu & A. Caginitoba); Nakobalevu, 1.5 km NE Colo-i-Suva Village, 18°03'S 178°25'E, 340 m, 29.vi.2002, sifted litter (M. Tokota'a); Nakobalevu, 1.5 km NE Colo-i-Suva Village, 18°03'S 178°25'E, 340 m, 8.iv.2003 (M. Tokota'a); Nakobalevu, 1.5 km NE Colo-i-Suva Village, 18°03'S 178°25'E, 340 m, 24.iv.2003, sifted litter (M. Tokota'a &S.R. Prasad); Nakobalevu, 1.5 km NE Colo-i-Suva Village, 18°03'S 178°25'E, 340 m, 28.vii.2003, sifted litter (A. Rakabula); Nakobalevu, 1.5 km NE Colo-i-Suva Village, 18°03'S 178°25'E, 340 m, 28.vii.2003, sifted litter (A. Rakabula); Mt. Korobaba, near Lami Town, 18°01'S 178°21'E, 300 m, 10.ii.2003, sifted litter (A. Tabutabu); Mt. Korobaba, near Lami Town, 18°01'S 178°21'E, 300 m, 6.viii.2003, sifted litter (M. Tokota'a); 2.7 km NE Naikorokoro Village, 18°05'S 178°19'E, 300 m, 29.vii.2003, sifted litter (A. Rakabula); Abaca Village, 17°40'S 177°21'E, 704m, 7.vi.2004 (D. F. Ward); Vaturu Dam, 17°45'S 177°35'E, 484 m, 7.vii.2004 (D. F. Ward). Vanua Levu: 2 km NNW Kasavu Village, 16°42'S 179°39'E, 300 m, 28.viii.2003, sifted litter (A. Rakabula); Mt. Vatudiri, 3km NW Waisali Village, 16°37'42"S 179°12'29"E, 641m, 2.ix.2006, in dead tree fern (E.M. Sarnat #2393); 2 km NW Nakanakana Village, 16°37'S 179°50'E, 300 m, 27.viii.2003, sifted litter (A. Rakabula); 3.5 km NW Vuya Village 16°59'S 178°43'E, 300 m, 28.xi.2004, sifted litter (A. Rakabula); Lasema (W.M. Mann); Ndreketi 25.X.1977 (G. Kuschel); Suene (W.M. Mann).

Discussion. Lordomyrma tortuosa , together with L. desupra, L. stoneri and L. vuda lacks a transverse carina on the dorsal face of its propodeum posterior to the metanotal groove and possesses a robust promesonotum that bulges above the level of its head and propodeum. It can be readily distinguished from these three by the frontal carinae that join with the arcuate carinae posterior of the eye, and the presence of longitudinal carinae that run immediately inward from the frontal carinae. Although the number and strength of these carinae vary, the variation does not appear to follow a distinguishable geographic pattern.

Distribution and Biology. With many records from 8 of the archipelago's islands, L. tortuosa is far and away the most geographically widespread of Lordomyrma species occurring in Fiji. The species is often collected from leaf litter, and nests of small colonies have been found in logs and under stones. Additionally, L. tortuosa appears to be restricted to the lower elevations of the islands, with only two of the aforementioned 32 records being recorded from above 500 m. Mann (1921) notes that he often found workers of this species foraging on mossy stones in ravines, and I have also observed workers gleaning the surfaces of stones on the banks of rivers.