Camponotus descarpentriesi Santschi

Rakotonirina, Jean Claude, Csősz, Sándor & Fisher, Brian L., 2017, Taxonomic revision of the Malagasy Camponotus grandidieri and niveosetosus species groups (Hymenoptera, Formicidae) using qualitative and quantitative morphology, Zootaxa 4238 (2), pp. 203-245 : 231-233

Camponotus descarpentriesi Santschi

( Figures 6 C–D, 15, 23)

Camponotus descarpentriesi Santschi, 1926: 263 . Lectotype minor worker, present designation, Madagascar, Province Antananarivo, Massif de l’Ankaratra, Ambahona , -20.04, 47.19165, 1800 m (J. Descarpentries), AntWeb CASENT0101206 ( NHMB) [examined] . Paralectotypes: 2 major workers, 1 queen and 1 male with same data as lectotype but with specimen codes: CASENT0101202, CASENT0101205; CASENT0101203 (queen), CASENT0101204 (male) ( NHMB) .

Diagnosis. Body color generally black; posterior portion of head, dorsum of mesosoma, and lateral margin of propodeal declivity with randomly scattered, whitish, erect hairs; with head in full-face view, erect hairs absent immediately behind lateral margin of clypeus, whitish erect hairs posteriorly confined to posterolateral angle of head, median clypeal carina not visible, eyes located in posterior fifth of head; in lateral view, mesosoma long and low; propodeal dorsum longer than declivitous face; fewer whitish erect hairs present on dorsum of body, only one row of hairs present from upper half to apex of petiolar node; transverse light strip on posterior margin of abdominal tergites narrow, width 1/8 the visible width of tergite.

Description. Minor worker. In full-face view head elongate (CWb/CL: 0.86–0.90), lateral borders straight, feebly diverging posteriorly; posterior margin broadly convex. Eyes protruding, located roughly at posterior fifth of head (PoOc/CL: 0.18±0.01, 0.17–0.19) and rarely breaking lateral outlines of head (CWb/CL: 0.86–0.90; CW/CL, 0.85–0.91). With head in full-face view, anteromedian margin of clypeus bluntly angulate, anterolateral corner rounded; median portion convex, making longitudinal, median carina faintly visible; posterior border feebly notched medially. Mandible subtriangular, masticatory margins equipped with six teeth. Antennal scape long (SL/ CS: 1.14±0.02, 1.11–1.17), approximately its distal portion extending beyond posterior cephalic margin, its basal half cylindrical. In lateral view, mesosoma long and low (MPH/ML: 0.40±0.01, 0.39–0.42); promesonotum more or less convex; propodeal dorsum slightly decreasing in height posteriorly, with transverse concavity at midlength, longer than declivotous face. In dorsal view, metanotal groove slightly impressed. Propodeal spiracle opening slitlike. Petiolar node compressed anteroposteriorly and tapering dorsally; anterior face generally convex and posterior face straight. Tibia of middle and hind legs with pectinate spurs. Transverse strip on posterior margin of gastral tergites narrow, maximum width roughly 1/10 the visible width of second tergite.

Head and mesosoma finely and densely reticulate punctate; their lateral portion with much larger punctures. Gastral tergites finely imbricate. Mandible coriarious with sparse piligerous punctures. Whitish erect hairs randomlyspread along median sectionof head capsule to its posterior fourth portion, where they are transversally scattered to the posterolateral corner of head. Erect hairs lacking immediately behind lateral clypeal margin. Anteromedian portion of head dorsum and gastral tergites covered with hairs thinner than those of posterior cephalic margin and dorsum of body. Petiolar node and posterior portion of propodeum with several hairs at least twice as long as those on promesonotum. Pubescence whitish yellow, sparse on dorsum of head and becoming increasingly abundant toward gastral tergites. Body color black and matte; basal portion of antennal scape, tip of mandible, and legs brown.

Major worker. Characteristics of minor worker, except: head much larger (CS: 1.94±0.09, 1.88–2.01; CWb/ CL: 0.98±0.02, 0.97–1); lateral margins broadly convex and gradually converging towards base of mandibles. Mandibles more powerful, apical margin armed with seven teeth. Clypeus short and trapezoid (ClyL/GPD: 0.56±0.06, 0.51–0.60), length roughly one fourth length of head (ClyL/CL: 0.23±0.01, 0.23–0.23), its anterolateral angle more rounded and anteromedian margin generally convex. Eyes located more in front of head capsule (CWb/ CL: 0.98±0.02, 0.97–1; CW/CL: 0.87±0.02, 0.85–0.87), level of posterior margin at posterior fourth of head capsule (PoOc/CL: 0.24±0.02, 0.23–0.25). Apical fourth of antennal scape surpassing posterior cephalic margin (SL/CS: 0.85±0.1, 0.78–0.92). In dorsal view, metanotal groove obsolete; metanotum indistinct; in lateral view, propodeum feebly at lower level with respect to promesonotum. In lateral view, petiolar apex higher and node more flattened anteroposteriorly. Head capsule finely and densely reticulate punctate to finely imbricate; sparse pubescence arises from middle of two to five smaller punctures embedded in one larger areole on lateral portion anterior to level of anterior margin of eye.

Discussion. Camponotus descarpentriesi and C. madagascarensis look very similar, but the latter has a higher and more robust mesosoma (MW/ML: 0.51±0.02, 0.47–0.58; MPH/ML: 0.41±0.03, 0.35–0.47), while the former is characterized by a lower, more slender mesosoma (MW/ML: 0.49±0.01, 0.47–0.50; MPH/ML: 0.40±0.01, 0.39– 0.42). In lateral view, the propodeal dorsum is straight in C. madagascarensis while with a transverse concavity at midlength in C. descarpentriesi . Also, C. madagascarensis has a visible longitidunal carina on the clypeus, but in C. descarpentriesi this longitudinal carina is indistinct, and the clypeus is only evenly convex medially. The pubescence is much denser and the transverse light strip on posterior margin of each gastral segment is narrower than in C. madagascarensis .

In the present study, the definition of C. descarpentriesi according to the qualitative morphology-based study is congruent with the study based on multivariate morphometric analysis. The existence of the species, which is supported by the grouping obtained from the clustering and the partitioning methods, is confirmed by shape PCA, and the samples are correctly identified by cumulative LDA at 100% success.

Distribution and biology. This species is unique to Madagascar and found only in the grassland and ericoid thickets of the central highlands. The species has been collected from Ambahona forest of Ankaratra massif in the north, Ankazomivady forest near Ambositra, and Andringitra National Parc in the south. The search for food is carried out terrestrially on the ground and through leaf litter, and arboreally on lower vegetation.

Additional material examined. MADAGASCAR: Province Toliara: 28 km SSW Ambositra, Ankazomivady , -20.775, 47.16833, 1670 m, grassland, (B.L. Fisher) ( CASC) ; Parc National d'Andringitra, Plateau d'Andohariana, 35.9 km 205° Ambalavao , -22.15233, 46.89917, 2000 m, ericoid thicket, (B.L. Fisher et al.) ( CASC) .

Figures

FIGURE 6. Head in full-face view, petiole and gastral segments in lateral view. A – B: C. madagascarensis (CASENT 0125551, CASENT 0101383). C-D: C. descarpentriesi (CASENT 0763876).