Camponotus aro, Rakotonirina & Fisher, 2022

Rakotonirina, Jean Claude & Fisher, Brian L., 2022, Revision of the Malagasy Camponotus subgenus Myrmosaga (Hymenoptera, Formicidae) using qualitative and quantitative morphology, ZooKeys 1098, pp. 1-180 : 1

Camponotus aro sp. nov.

Figs 25B , 31B , 41

Holotype worker.

Madagascar: Province Mahajanga: PN de Namoroka, 17.8 km 329° WNW Vilanandro, -16.37667, 45.32667, 100 m, dry forest, under stone, 08 Nov 2002 (Fisher, Griswold et al.) collection code: BLF06542, specimen code: CASENT0489917 ( CAS).

Paratypes.

2 minor workers and 1 major worker with same data as holotype but with specimen codes: CASENT0837586, CASENT0837587, CASENT0489918 ( NHMUK, MHNG, CAS).

Additional material examined.

Madagascar: Mahajanga: PN Namoroka, 16.9 km 317° NW Vilanandro , -16.40667, 45.31, 100 m, tropical dry forest (Fisher, Griswold et al.) ( CAS); PN Namoroka, 17.8 km 329° WNW Vilanandro, -16.37667, 45.32667, 100 m, tropical dry forest (Fisher, Griswold et al.) ( CAS) .

Diagnosis.

With head in full-face view, lateral margins of head anterior to eye level parallel, lacking erect hairs, lateral cephalic margin rounding to posterior margin, anteromedian clypeal margin continuously forming broad convexity; propodeal dorsum immediately posterior to metanotal groove convex, then concave medially and rounding to declivity surface.

Description.

Minor worker. In full-face view, head widest at midlength; lateral margins posterior to level of eye, rounding evenly to posterior margin; eye protruding and large (EL/CS: 0.25 ± 0.01; 0.23-0.26), not breaking lateral cephalic margin; level of its posterior border located at ca. posterior 1/3 of head (PoOc/CL: 0.28 ± 0.01; 0.27-0.30); frontal carinae posteriorly parallel (FR/CS: 0.25 ± 0.01; 0.24-0.27); clypeus without anterolateral angle, its anteromedian margin broadly convex; mandible with six teeth, its two apical teeth distantly spaced; antennal scape relatively long (SL/CS: 1.59 ± 0.08; 1.46-1.71). Mesosoma long and low (MPH/ML: 0.28 ± 0.01; 0.26-0.30), promesonotum weakly convex, mesonotum with posterior portion flat immediately anterior to a weakly visible metanotal groove; propodeal dorsum anteriorly convex, with feeble concavity medially, dorsal margin of propodeum rounding to declivity; propodeal dorsum 2 × as long as declivity. Petiolar node nodiform; with dorsal margin inclined posteriorly and forming a blunt angle to anterior face; anterior face of petiolar node 1/2 height of posterior face; femur of hind leg rounded axially and twisted basally.

First and second gastral tergites with a pair of white spots; erect hairs on lateral margin of head absent; two erect hairs present near posterior margin of head; antennal scape only covered with appressed hairs; pronotum with a pair of erect hairs; posterodorsal angle of propodeum with a pair of erect hairs.

Major worker. Differing from minor worker in the following characters: enlarged head (CS: 3.10 ± 0.18; 2.82-3.29; CWb/CL: 0.92 ± 0.01; 0.90-0.94) with markedly concave posterior margin; apical 1/3 of antennal scape extending beyond posterior cephalic margin; robust mesosoma with propodeal dorsum slightly concave and its length ca. 2 × height of declivity; petiole tapering dorsally.

Distribution and biology.

Geographically restricted to the PN Namoroka in the western dry forest of Madagascar (Fig. 41D ), C. aro has been found nesting under stones while workers forage on the ground or through leaf litter and on lower vegetation.

Discussion.

Camponotus aro is morphologically similar to C. gouldi in that both species are characterized by a broadly convex anteromedian margin of clypeus, but the latter species is diagnosed as having a head that extends posteriorly into a broad, short neck and its propodeal dorsum is straight.

The definition for C. aro is supported by the congruence between the results of traditional qualitative morphology and the NC-clustering technique. The classification of the samples for the species is at 100% success.

Etymology.

The species name aro is a non-Latin singular noun used in apposition.

Figures

Figure 25. Head in full-face view A C. tapia (CASENT 0217310) B C. aro (CASENT 0489917).

Figure 31. Head in full-face view A C. gouldi (CASENT 0121617) B C. aro (CASENT 0489917).

Figure 41. Camponotus aro A lateral view B head in full-face view C dorsal view of holotype minor worker CASENT 0489917 D distribution map.