Camponotus tratra Rakotonirina, Csosz & Fisher

Rakotonirina, Jean Claude, Csosz, Sandor & Fisher, Brian L., 2016, Revision of the Malagasy Camponotusedmondi species group (Hymenoptera, Formicidae, Formicinae): integrating qualitative morphology and multivariate morphometric analysis, ZooKeys 572, pp. 81-154 : 133-134

Taxon classification Animalia Hymenoptera Formicidae

Camponotus tratra Rakotonirina, Csosz & Fisher sp. n. Figures 17A, 17B, 31, 46

Holotype worker.

Madagascar, Province Toamasina, Parc National de Zahamena, Sahavorondrano River, -17.75257, 48.85725, 765 m, rainforest, beating low vegetation, 23 Feb 2009 (B.L. Fisher et al.) collection code: BLF22401, specimen code: CASENT0153055 (CASC).

Additional material examined.

MADAGASCAR: Province Antsiranana, Makirovana forest, -14.17066, 49.95409, 225 m, rainforest, (B.L. Fisher et al.) (CASC); Parc National Montagne d’Ambre [1st campsite], -12.51444, 49.18139, 960 m, rainforest, (R. Harin’Hala) (CASC); Réserve Spéciale Manongarivo, 10.8 km 229° SW Antanambao, -13.96167, 48.43333, 400 m, rainforest, (B.L. Fisher) (CASC); Province Fianarantsoa: 1 km E of Isalo National Park Interpretive Center, -22.62667, 45.35817, 885 m, dry wash (R. Harin’Hala) (CASC); stream area, 900 m E of Isalo National Park Interpretive Center, -22.62667, 45.35817, 750 m, open area near stream, (R. Harin’Hala) (CASC); Province Toamasina: Parc National Zahamena, Sahavorondrano River, -17.75257, 48.85725, 765 m, rainforest, (B.L. Fisher et al.) (CASC); Province Toliara: Parc National Andohahela, Col de Tanatana, 33.3 km NW Tolagnaro, -24.7585, 46.85367, 275 m, rainforest, (B.L. Fisher et al.) (CASC).

Diagnosis.

In profile, anterior and posterior margins of petiolar node convex; in profile, propodeal dorsum and declivitous surface separated by blunt angle; in dorsal view, mesonotum less than twice as broad as long; mesopleuron with propodeal surface together distinctly wider than lateral portion of pronotum; in profile, propodeal dorsum roughly as long as declivitous margin; dorsum of head and mesosoma smooth and shiny or imbricate; in profile, mesonotal dorsum strongly sloping down to the level of propodeum, maximum length of mesonotum about as long as distance between metanotal groove and propodeal spiracle; in dorsal view, lateral margin of mesonotum not well defined and converging gradually towards metanotal groove.

Description.

Minor worker (Figs 17A, 17B, 31). In full-face view head roughly as long as broad (CWb/CL: 0.91-0.97), lateral borders more or less straight and weakly diverging posteriorly; posterior cephalic margin broadly convex. Level of posterior ocular margins located at less than posterior fifth portion of head (PoOc/CL: 0.19-0.22). Anterior clypeal margin broadly convex. Mandible triangular, armed with six teeth. Antennal scape relatively long (SL/CS: 0.96-1.13), apical half almost surpassing posterior cephalic border. Pronotal dorsum flattened, anterodorsal angle projecting anteriorly narrow edge; dorsolateral portion without margination. In dorsal view, mesonotum less than twice as broad as long; lateral margin of mesonotum not well defined and converging gradually towards metanotal groove; in lateral view, mesonotal dorsum inclined posteriorly and lowering level of propodeum; length of mesonotum about as long as distance between metanotal groove and propodeal spiracle. In lateral view, dorsum of propodeum raised into a very short edge and then suddenly inclined posteriorly to join the declivitous surface. In lateral view, dorsolateral carina of propodeum weakly visible and roughly as long as declivitous margin; meso-metapleuron and lateral propodeal surface together distinctly broader than lateral portion of pronotum. Coxa of foreleg broad, maximum width greater than width of meso-metapleuron. In profile, anterior and posterior margins of petiolar node convex and rounding dorsal margin. Constriction between abdominal segments III and IV lacking.

Dorsum of head, mesosoma, petiolar node, and gastral tergite smooth and shining, superimposed with fine and dense imbrication and small punctures from which erect hairs and pubescence arise. Mandible sparsely punctulate. Pronotal dorsum without erect hairs; mesonotum with one pair, and propodeum with two or more pairs; erect hair lacking just above propodeal spiracle. Posterior face of petiolar node near lateral margin and posterodorsal angle with a row of four erect hairs; slender erect hairs arranged transversely on dorsum of petiolar node, on anterior and posterior portions of each gastral tergite. Body color generally brown, with much darker head, mesonotum, propodeum, and petiolar node.

Major worker. With characteristics of minor worker except for the following features: larger head (CS: 1.58) with straight rear margin; level of posterior margin of eyes located at about posterior third of head (PoOc/CL: 0.3); anterior clypeal margin transverse; antennal scape barely extending beyond posterior cephalic margin (SL/CS: 0.75); more robust mandible; two pairs or more of whitish erect hairs on dorsum of pronotum, mesonotum, and propodeum.

Distribution and biology.

Known only from Madagascar, Camponotus tratra has a sparse but wide distribution from Parc National Montgne d’Ambre in the north through Makirovana Forest in the northeast and Réserve Spéciale Manongarivo in the northwest, to Parc National Zahamena in the central east and Parc National Andohahela in the southeast (Fig. 46). Workers of this species have been sampled most often from low vegetation and rarely from leaf litter and one nest was found in dead branches above the ground.

Discussion.

Camponotus tratra is very similar to Camponotus zavo and Camponotus varatra , but the latter two species have a mesonotal dorsum slightly inclined posteriorly whose length is distinctly shorter than the distance between the metanotal groove and the propodeal spiracle in profile. Also, in the two latter species the lateral margins of the mesonotum are well defined and convex in dorsal view, converging strongly towards the metanotal groove.

The NC-clustering method groups all samples of Camponotus tratra together in the dendrogram with a classification success of 100%. However, one specimen of Camponotus varatra was placed in the Camponotus tratra cluster and was misclassified by confirmatory LDA with a posterior probability of 0.74. This may be due to the fact that both species are very closely related and have some overlap in their morphometric and qualitative descriptions. However, as discussed above, these species can be distinguished based on few qualitative morphological traits, one of which was not captured by the multivariate morphometric analysis. In addition, biological data for Camponotus tratra suggest that its nest sites are arboreal and could be located higher in the vegetation strata. By contrast, Camponotus varatra prefers nesting in dead branches above the ground or in lower vegetation.