Lasiomyrma

A small genus from southeast Asia. Two species have been found nesting in rotten wood on the forest floor, but little else is known about their biology.

Identification
Terayama & Yamane (2000) - Lasiomyrma most resembles the genera Indomyrma from India and Tetheamyrma from Malaysia in sharing the 11-segmented antennae and the virtual absence of antennal scrobes (weakly defined in Indomyrma) (Bolton, pers. comm.). It is distinguished from Indomyrma by the position of propodeal spiracle (spiracle situated close to the margin of propodeal declivity in Indomyrma) and the absence of antennal scrobes, and from Tetheamyrma by the 3-segmented antennal club (2-segmented in Tetheamyrma) and the absence of spongiform appendages on ventral surfaces of petiole and postpetiole. This new genus is separated from the other stenammine genera by the combination of the 11-segmented antennae with a 3-segmented club, the obtusely angulate anterior margin of clypeus, the absence of antennal scrobes, and the propodeal spiracles located at almost modlength of the sclerite. The obtusely angulate anterior clypeal margin, is possibly autapomorphic within this tribe.

General (2015) - Lasiomyrma has an anterior median clypeus produced into an obtuse angle, 11 or 12 segmented antenna, elongate-triangular mandibles that usually close tightly with anterior clypeal margin (line drawing of frontal head shows a gap in Lasiomyrma gracilinoda), flat dorsum of promesonotum and propodeum, propodeal spines present, and a pedunculate petiole (Terayama & Yamane 2000).

Eguchi, Bui and Yamane (2011) - All of the described species of Lasiomyrma have 11-segmented antennae (Terayama & Yamane 2000, Jaitrong 2010). However, a single worker of Lasiomyrma collected from northern Vietnam (L. sp. eg-1) has 12-segmented antennae, thus the worker diagnosis of the genus given in Terayama & Yamane (2000) should be widened as “antenna 11- or 12-segmented”. The worker of Lasiomyrma is morphologically very similar to those of Lordomyrma bhutanensis and Lordomyrma sinensis. These Lordomyrma species completely lack antennal scrobes and have the apex of anterior clypeal margin with a small projecting tooth.

Nomenclature

 *  LASIOMYRMA [Myrmicinae: Stenammini]
 * Lasiomyrma Terayama & Yamane, 2000: 523. Type-species: Lasiomyrma gedensis, by original designation.

Worker
Monomorphic terrestrial myrmicine ants with the following combination of characters.

1. Palp formula 2, 2 (one paratype specimen dissected).

2. Mandible elongate-triangular, with 7 teeth which decrease in size from apex to base.

3. Anterior clypeal magin forming an obtuse angle, lacking an isolated median seta.

4. Median portion of clypeus narrowly inserted between the frontal lobes.

5. Median portion of clypeus with a pair of weak longitudinal carinae.

6. Frontal lobes narrow, each lobe almost as wide as the median portion of clypeus that is inserted between them.

7. Frontal carinae and antennal scrobes absent.

8. Eye moderate in size, positioned in front of the midlength of the sides of the head.

9. antenna 11- or 12-segmented (modified from originally stated 11 segmented; Eguchi, Bui and Yamane, 2011); scape short (SI 6G-70), 4th to 8th segments each wider than long; apical 3 segments forming a distinct club.

10. Alitrunk low in profile; promesonotal dorsum flat or slightly convex, with dully angulate anterior humeri, and widest at anterolateral angles.

11. Metanotal groove present.

12. Propodeum with a pair of short teeth.

13. Propodeal spiracle located at or just behind of the midlength of the sclerite, and high on side.

14. Propodeal lobe present, small to moderately long; posteriormost portion forming an angle.

15. Metasternal process absent.

16. Tibial spurs absent on middle and hind legs.

17. Petiole pedunculate; subpetiolar process absent.

18. Cuticle thick and densely sculptured; pilosity fine and dense over the dorsal surface of body.

Queen
Similar to the worker but larger in body size. Ocelli present. Alitrunk with full complement of flight sclerites and certainly winged when virgin.

Eguchi, Bui and Yamane (2011) - The worker of the single known Vietnamese species has the following features. Worker probably monomorphic; head in lateral view subrectangular; frontal carina and antennal scrobe absent;median portion of clypeus forming steep anterior face, with weak submedian carinae; anteromedian portion of clypeus forming a transverse strip with anterior margin weakly pointed in middle, lacking an isolated median seta; posteromedian portion of clypeus relatively narrowly inserted between frontal lobes; mandible elongate-trianglar, with 8 teeth that decrease in size from apex to base; antenna 12-segmented, with inconspicuous 3-segmented club;eye well developed; promesonotum in lateral view slightly convex, only a little higher than anterior border of propodeum, in dorsal view with obtusely angulate humeri; promesonotal suture absent dorsally; metanotal groove distinct; propodeal spine distinct; propodeal lobe present as a small angulate lobe; petiole pedunculate, with high and thin node; postpetiole higher than long, in lateral view roundly convex dorsally; gastral shoulder absent.

Etymology
Lasio, Gr., hairy+myrma, Gr., ant.