Camponotus gibber Forel, 1891

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 gibber Forel

Figs 32B , 35C , 38A , 53

Camponotus quadrimaculatus var. gibber Forel, 1891: 59. Lectotype minor worker, by present designation, Madagascar, Andrangoloaka (Sikora) AntWeb CASENT0101513 (MHNG) [examined]. Paralectotype. 1 minor worker and 1 alate queen of same data as lectotype but with the following specimen codes: CASENT0101528, CASENT0101537 (MHNG) [examined]. Raised to species by Forel 1891: 215; 1892: 232; Dalla Torre 1893: 232; Emery 1896: 374; Wheeler 1922: 1054; Emery 1925: 122; Bolton 1995: 101. [Combination in Camponotus (Myrmosphincta) Forel, 1914: 273; in Camponotus (Mayria) Emery, 1925: 122].

Additional material examined.

Madagascar: Antananarivo: [(de Diversa); Museum Paris, Grandidier 1899]; Mantasoa; Manjakandriana, -19.033333, 47.9166666, 1409 m (CAS); [Madagascar central]; Ambatomanjaka; Miarinarivo, -18.766947, 46.869107, 1343 m (CAS). Antsiranana: Ambondrobe, 41.1 km 175° NW Vohemar, -13.71533, 50.10167, 10 m, littoral rainforest (B.L. Fisher) (CAS); RS Manongarivo 17.3 km 218° SW Antanambao, -14.02167, 48.41833, 1580 m, montane rainforest (B.L. Fisher) (CAS); RS Manongarivo, 14.5 km 220° SW Antanambao, -13.99833, 48.42833, 1175 m, montane rainforest (B.L. Fisher) (CAS); RS Manongarivo, 14.5 km 220° SW Antanambao, -14.00, 48.43167, 1220 m, montane rainforest (B.L. Fisher) (CAS); PN Marojejy, Antranohofa, 26.6 km 31° NNE Andapa, 10.7 km 318° NW Manantenina, -14.44333, 49.74333, 1325 m, montane rainforest (B.L. Fisher) (CAS); RS Manongarivo, 17.3 km 218° SW Antanambao, -14.02167, 48.41833, 1600 m, montane rainforest (B.L. Fisher) (CAS); PN Marojejy, 11 km NW Manantenina, -14.45, 49.73333, 1875 m, montane rainforest (E.L. Quinter) (CAS). Fianarantsoa: [Hte Sahandrata; Forét prim. de Tsianovoha]; Ambohimitombo; Ambositra, -20.72, 47.45, 1172 m (P.S. Ward) (PSWC): 2 km W Andrambovato, along river Tatamaly, -21.51167, 47.41, 1075 m, montane rainforest (B.L. Fisher et al.) (CAS); 3 km W Ranomafana, nr. Ifandiana, -21.25, 47.41667, 950 m, rainforest (P.S. Ward) (CAS); 43 km S Ambalavao, PN Andringitra, -22.23333, 47, 825 m, rainforest (B.L. Fisher) (CAS); Forêt d’Atsirakambiaty, 7.6 km 285° WNW Itremo, -20.59333, 46.56333, 1550 m, montane rainforest (Fisher, Griswold et al.) (CAS); Ambinanindranomena Non Protected Area, 39.16 km SE Ambalavao, -21.96007, 47.29125, 1002 m, Savannah grassland (A. Ravelomanana) (CAS); Ambinanindranomena Non Protected Area, 39.45 km SE Ambalavao, -21.95386, 47.29427, 1069 m, montane rainforest (A. Ravelomanana) (CAS); Ampanenitra Non Protected Area, 41.19 km SE Ambalavao, -21.9652, 47.31001, 1010 m, Savannah grassland (A. Ravelomanana) (CAS); Andrambovato along river Tatamaly, -21.50967, 47.40762, 984 m, cultivated land (tavy) (B.L. Fisher et al.) (CAS); Belle Vue trail, PN Ranomafana, -21.2665, 47.42017, 1020 m, mixed tropical forest (R. Harin’Hala) (CAS); Vatovavy Fitovinany Region, District of Ifanadiana Belle vue area 1.2 km S of PN Ranomafana entrance, -21.2665, 47.42017, 1018 m, rainforest ( Rin’Ha, Mike) (CAS); Vatovavy Fitovinany Region, District of Ifanadiana Belle vue area 1.2 km S of PN Ranomafana entrance, -21.2665, 47.42017, 1018 m, rainforest ( Rin’Ha, Mike) (CAS); Vatovavy Fitovinany Region, District of Ifanadiana, 12 km W of Ranomafana, -21.25083, 47.40717, 1127 m, forest edge, open area ( Rin’Ha, Mike) (CAS); JIRAMA water works near river, PN Ranomafana, -21.2485, 47.45217, 690 m, open area near stream (R. Harin’Hala) (CAS); Namorona River at footbridge, PN Ranomafana, -21.25833, 47.42178, 850 m, mixed tropical forest near river, ME Irwin & EI Schlinger (CAS); PN Ranomafana, Sahamalaotra River, 6.6 km 310° NW Ranomafana, -21.23667, 47.39667, 1150 m, montane rainforest (Fisher, Griswold et al.) (CAS); PN Ranomafana, Vatoharanana River, 4.1 km 231° SW Ranomafana, -21.29, 47.43333, 1100 m, montane rainforest (Fisher, Griswold et al.) (CAS); PN Ranomafana, Talatakely, -21.24833, 47.42667, in bamboo forest (CE Griswold, DH Kavanaugh, ND Penny, MJ Raherilalao, JS Ranorianarisoa, J Schweickert) (CAS); RS Ivohibe 8.0 km E Ivohibe, -22.48333, 46.96833, 1200 m, montane rainforest (B.L. Fisher, Sylvain) (CAS); radio tower, PN Ranomafana, -21.25833, 47.40717, 1130 m, forest edge, mixed tropical forest, open area (M.E. Irwin, F.D. Parker, R. Harin’Hala) (CAS); Ranomafana, -21.25, 47.36667 (A. Pauly) (CAS); Ranomafana Nat. Park, Talatakely forest; Sahambavy; Fianarantsoa Rural, -21.4511792, 47.3023894, 1139 m (V.F. Lee, K.J. Ribardo,) (CAS); PN Ranomafana, Talatakely area, 0.4 km WSW of Park Entrance, -21.41667, 47.68333, 900 m, mixed tropical forest (D.H. & K.M. Kavanaugh) (CAS); Vohiparara, -21.23333, 47.36667 (A. Pauly) (CAS); Vohiparara broken bridge, -21.22617, 47.36983, 1110 m, high altitude rainforest (R. Harin’Hala) (CAS); 23 km E Moramanga, -18.98028, 48.45306, 900 m, tropical dry forest (B.L. Fisher) (CAS). Toamasina: 6.9 km NE Ambanizana, Ambohitsitondroina, -15.56667, 50, 1080 m, montane rainforest (B.L. Fisher) (CAS); 6 km ESE Andasibe (= Perinet), -18.95, 48.46667, 900 m, rainforest (P.S. Ward) (CAS); Bevolota 17.1 km N Andasibe, -18.77071, 48.43164, 995 m, montane rainforest (B.L. Fisher et al.) (CAS); Corridor Forestier Analamay-Mantadia, Ambatoharanana, -18.80424, 48.40081, 968 m, rainforest (B.L. Fisher et al.) (CAS); Corridor Forestier Analamay-Mantadia, Ambatoharanana, -18.79956, 48.4028, 1058 m, rainforest (B.L. Fisher et al.) (CAS); forêt Didy, Ambatondrazaka, -18.1111503, 48.5107283, 1029 m, rainforest (A. Pauly) (CAS); Mahavelona (Foulpointe), -17.66667, 49.5, Pandanus marsh (A. Pauly) (CAS); Morarano-Chrome, 25 km W forét I, -17.75, 47.98333 (A. Pauly) (CAS); PN Mantadia, -18.79167, 48.42667, 895 m, rainforest (H.J. Ratsirarson) (CAS); PN Andasibe-Mantadia, Forêt de Mantadia, 25.7 km 248° Moramanga, -18.81402, 48.43028, 1040 m, rainforest (F.N. Raharimalala, B. Blaimer) (CAS); Réserve Perinet-Analamazaotra, -18.93333, 48.43333, 950 m, rainforest (D.M. Olson) (CAS). Toliara: 13 km NW Enkara, PN Andohahela, -24.55, 46.8, 1160 m, montane rainforest (B.L. Fisher) (CAS); 13 km NW Enkara, PN Andohahela, -24.56667, 46.81667, 850 m, rainforest (B.L. Fisher) (CAS); Anosy Region, Anosyenne Mts, 31.2 km NW Manantenina, -24.13894, 47.06804, 1125 m, rainforest (B.L. Fisher, F.A. Esteves et al.) (CAS); Forêt Ivohibe 55.6 km N Tolagnaro, -24.56167, 47.20017, 650 m, rainforest (B.L. Fisher et al.) (CAS); Ifaty 22 km N, -23.18333, 43.61667, 30 m, beach dunes (M.E. Irwin and E.I. Schlinger) (CAS); near road, PN Zombitse, -22.8405, 44.73117, 825 m, spiny deciduous forest (R. Harin’Hala) (CAS).

Diagnosis.

In full-face view, lateral margins of head anterior to eye level diverging posteriorly; anterior clypeal margin truncate; two pairs of white spots present on second and third abdominal tergites; pronotum, mesonotum, and propodeum forming separate convexities, metanotal groove depressed; level of propodeum lower than that of promesonotum.

Description.

Minor worker. In full-face view, head sides diverging towards broadly convex posterior margin; eye slightly protruding and small (EL/CS: 0.27 ± 0.01; 0.24-0.30), not breaking lateral cephalic margin, level of its posterior margin located at ca. posterior 1/4 of head (PoOc/CL: 0.25 ± 0.01; 0.23-0.28); frontal carinae wide and diverging posteriorly (FR/CS: 0.35 ± 0.01; 0.33-0.36), distance between them larger than their smallest distance to eye; clypeus with anterolateral angle and straight anteromedian margin; mandible with two apical teeth distant from each other; antennal scape relatively long (SL/CS: 1.17 ± 0.07; 0.93-1.27). Pronotum and mesonotum forming a separate convexity; propodeal dorsum convex anteriorly, concave medially, then flat posteriorly, joining declivity in noticeable angle; metanotal groove weakly visible; propodeal declivity 3/4 length of dorsum. Petiolar node short and high, with dorsal margin straight then rounding to both anterior and posterior faces; anterior face almost 2/3 height of posterior face; femur of hind leg rounded axially, not twisted basally.

First and second gastral tergites with a pair of white spots; lateral margin of head without erect hairs; three pairs of erect hairs present near posterior margin of head; antennal scape only covered with appressed hairs; pronotum with few erect hairs; mesonotum with a pair of erect hairs; posterodorsal corner of propodeum with two pairs of erect hairs. Body color shining brown to dark brown; apical section of appendages lighter in color.

Major worker. With characteristics of minor worker except: enlarged head (CS: 2.45 ± 0.21; 2.21-2.82; CWb/CL: 1.05 ± 0.04; 1.01-1.10) with broadly concave posterior margin; anteromedian clypeal margin noticeably excised medially; antennal scape hardly extending beyond posterior cephalic margin; robust mesosoma, pronotum, and mesonotum an even convexity, metanotum distinct, propodeal dorsum sloping straight to declivity, approximately the same length as declivity; petiolar node more flattened anteroposteriorly.

Distribution and biology.

Camponotus gibber occurs in mid-altitude rainforest, montane rainforest, open areas on the forest edge, and the savannah grassland of the high plateau of Madagascar. Its distribution ranges from the RS Manongarivo and PN Marojejy in the north through the Corridor Forestier Analamay-Mantadia and PN Andringitra in the south-central region to the PN Andohahela and Anosyenne Mountains in the south. It has also colonized the littoral rainforest of Ambondrobe Vohemar, the dry forest of the PN Isalo, and cultivated land in the Andrambovato Forest (Fig. 53D ). Individual workers forage mostly on the ground and through leaf litter, and rarely on lower vegetation. Nests are typically in rotten logs and rotting tree stumps, but seldom in the ground, in root mats on the ground, in dead twigs above the ground, in moss and leaf litter on live trees, and under tree bark.

Discussion.

Camponotus gibber may be difficult to differentiate from C. rotrae and C. quadrimaculatus in that they have two pairs of white spots on the second and third abdominal tergites. In both latter species, however, the pronotum, mesonotum, and propodeum do not form separate convexities, the metanotal groove is not depressed, and the dorsal face of its petiolar node joins the posterior face at an angle.

There are apparently three forms within C. gibber . These are geographically isolated across their distribution along the eastern rainforest of Madagascar due to the presence of high mountain chains in northwestern Madagascar. In the first form, the mesosoma strongly forms separate convexities and the propodeal dorsum is more or less straight. The second form is characterized by a more or less continuous dorsal outline of the mesosoma and a broadly concave propodeal dorsum. The third form constitutes intermediate degrees of these phenotypic variations because workers present separate convexities of mesosoma and a slightly concave propodeal dorsum. The members of the first two forms show morphological variabilities that gradually merge in the third form.

The relatively low 91.89% classification success attained by LDA is due to the misclassification of three minor workers as C. quadrimaculatus . This is because the third variant in C. gibber and members of C. quadrimaculatus species share qualitative morphological traits, and both species display overlapping ranges of quantitative measurements. The grouping of C. gibber in the same cluster shown by the dendrogram of multivariate morphometric analysis corroborates the species hypothesized by the taxonomic revision based on qualitative morphology.

Figures

Figure 32. Head in full-face view A C. aurosus (CASENT 0064815) B C. gibber (CASENT 0188619).

Figure 35. Second and third abdominal tergites in dorsal view A C. kelimaso (CASENT 0487718) B C. quadrimaculatus (CASENT 0096044) C C. gibber (CASENT 0491497).

Figure 38. Mesosoma and petiolar node in lateral view A C. gibber (CASENT 0188619) B C. quadrimaculatus (CASENT 0096044).

Figure 53. Camponotus gibber A lateral view B head in full-face view C dorsal view of minor worker CASENT 0188619 D distribution map.