Recurvidris

Vietnamese Recurvidris species inhabit forest edges and woody habitats, but rarely grasslands. They nest in the soil and build a chimney-shaped mound on the nest entrance with soil particles. (Eguchi, Bui and Yamane 2011)

Identification
Eguchi, Bui and Yamane (2011) - The worker of Recurvidris is somewhat similar to that of Crematogaster (Orthocrema) species.

Jaitrong and Wiwatwitaya (2015) - Worker diagnosis: for a more extensive description of the worker caste of the genus, see Bolton (1992). Some of the important characteristics described by Bolton (1992) are reproduced here. Clypeus broad from front to back; antenna 11-segmented, with a conspicuous apical club of three segments; mandible with 4-5 teeth on masticatory margin; palp formula 4, 3; frontal carinae and antennal scrobes absent; propodeal spine present, curving upwards and forwards from its base; petiole pedunculate, with spiracle at about midlength of the peduncle, and node low and weakly conical in profile; first gastral segment in profile almost flat dorsally and strongly convex ventrally, with tergite strongly overlapping sternite laterally.

Distribution
Jaitrong et al (2019) - Recurvidris is distributed in Asia from India and Sri Lanka in the south and west; Japan, China and Taiwan in the north; various countries in Southeast Asia; and eastwards to Sulawesi in Indonesia.

Species by Region
Number of species within biogeographic regions, along with the total number of species for each region.

Worker Morphology
Note that the palp formula for Recurvidris recurvispinosa is reported as 4,3 by Sheela et al. (2000) and 5,3 by Harshana & Dey, (2021).

Nomenclature

 *  RECURVIDRIS [Myrmicinae: Crematogastrini]
 * Recurvidris Bolton, 1992: 36. Replacement name for Trigonogaster Forel, 1890b: cviii. [Junior homonym of Trigonogaster Guérin-Méneville, 1844b: 1149 (Hymenoptera, Pteromalidae).]
 * TRIGONOGASTER [junior homonym; see Recurvidris]
 * Trigonogaster Forel, 1890b: cviii. Type-species: Trigonogaster recurvispinosa, by monotypy. [Junior homonym of Trigonogaster Guérin-Méneville, 1844b: 1149 (Hymenoptera, Pteromalidae).]
 * Recurvidris Bolton, 1992: 36, replacement name for Trigonogaster Forel.

Eguchi, Bui and Yamane (2011) - Workers of Vietnamese species have the following features.Worker monomorphic; head in full-face view oval or subrectangular; frontal carina and antennal scrobe absent; median portion of clypeus in lateral view relatively steeply sloping anteriad; anterior clypeal margin lacking an isolated median seta; posteromedian portion of clypeus relatively broadly inserted between frontal lobes; mandible relatively narrow; masticatory margin oblique, with 4–5 teeth; antennae 11-segmented, with distinct 3-segmented club; eye well developed, weakly pointed anteroventrally; mesosoma long; promesonotal dome raised above anterodorsal border of propodeum, with a long posterior slope to propodeum; promesonotal suture absent dorsally; metanotal groove weakly impressed dorsally; propodeal spine curving upwards and forwards from base; propodeal spiracle located close to dorsal face of propodeum, far in front of base of propodeal spine; propodeal lobe vestigial; petiole pedunculate, with a tiny to large, triangular subpetiolar process; petiolar node low and weakly conical in lateral view; postpetiole in lateral view dorsoventrally narrowed posteriorly, in dorsal view broadly attached to first gastral segment; first gastral segment behind postpetiole in lateral view extremely dorsoventrally compressed; gastral shoulder absent.