Camponotus imitator Forel, 1891

Rasoamanana, Nicole, Csosz, Sandor & Fisher, Brian L., 2017, Taxonomic revision of imitating carpenter ants, CamponotussubgenusMyrmopytia (Hymenoptera, Formicidae) of Madagascar, using morphometry and qualitative traits, ZooKeys 681, pp. 119-152 : 121-123

Camponotus imitator Forel, 1891 Figures 1B, 4A, 5A, 9, 10, 11

Camponotus imitator Forel, 1891: 209, pl. 4, fig. 15; pl. 5, fig. 8. Lectotype worker, present designation, MADAGASCAR, Province Toliara, Morandava [-20.2833, 44.28333] (coordinates obtained from MBG Gazetteer), ( Grevé), CASENT0101365 (MHNG) [not examined morphometrically] and two paralectotypes, workers, MADAGASCAR, CASENT0101116 (NHMB): CASENT0104647 (ZMHB) [morphometrically not examined]. [Combination in Camponotus (Myrmosphincta) : Forel, 1912: 92; in Camponotus (Myrmopytia) : Emery, 1920: 257].

Camponotus imitator var. resinicola Santschi, 1911 133. Lectotype worker, present designation, MADAGASCAR, Ambolisatra (probably today’s Ambolisaka), [-21.7333, 43.36666], 6-7-1898, (C. Grandidier), CASENT0101117 (NHMB) [examined] and one paralectotype worker, Region du Sud, Andrahomana, [-25.183333, 46.63333], Nov. 1901 (Ch. Alluaud), CASENT0101118 (NHMB), and one worker Region du Sud-Est, Fort-Dauphin, [-25.03333, 46.98333], Août, 1901 (Ch. Alluaud), CASENT0101119 (NHMB) [not examined morphometrically]. syn. n. [Raised to species: Wheeler, W.M. 1922: 1049. Reverted to subspecies of imitator : Emery, 1925: 115].

Diagnosis.

Camponotus imitator is easily recognizable within the group on the basis of the following combination of characters: posterior region of head only slightly extended, not narrowed into a long neck in the minor worker, PoOC/CL 0.256 [0.224, 0.304] and trapezoidal in major worker, CWb/CL 0.951 [0.841, 1.031]; anterior clypeal margin with a rectangular projection ClyL/CL 0.289 [0.231, 0.316]; petiole nodiform PEW/CS 0.224 [0.203, 0.255]; both castes bicolored: head, mesosoma and appendages reddish brown to dark brown, gaster black (minor) to mainly black (major).

Description of minor worker.

Head suboval, posterior region of head only slightly and broadly extended with margins weakly convex. (CS) 1.68 mm [1.34, 2.18] (n=25). Standing setae present on posterolateral margin of head and vertex in full-face view. Eyes situated on posterior half of head, PoOC/CL 0.253 [0.224, 0.293]. Frontal carina convex, FR/CS 0.254 [0.209, 0.280], antennal scape surpassing posterior margin of head by more than half its length, SL/CS 1.517 [1.211, 1.731]. Anteromargin of clypeus with broad rectangular projection, posterior margin concave, ClyL/CL 0.271 [0.231, 0.293]; mandible with six teeth, palps long with respect to head size.

Pronotum weakly undulant. Suberect pronotal setae numerous (more than 12). Mesonotum straight, MPD/CS 1.181 [0.954, 1.403]. Erect mesonotal setae varying from absent to numerous (two or three pairs anterior to mesothoracic spiracle). Mesothoracic spiracles prominent; propodeal dorsum protuberant. Erect propodeal setae moderate in number (4-6). ML/CS 1.957 [1.670, 2.149]. Petiole nodiform, dorsum of node convex, petiole higher than broad, PEW/CS 0.242 [0.164, 0.264]. Erect setae present on petiolar apex.

Color: head and mesosoma red to reddish brown, gaster dark brown to black. Erect setae light brown. Sparse appressed pubescence present.

Description of major worker.

In full-face view, head truncated posteriorly, evenly tapering to base of mandibles, posterior margin of head weakly concave. Absolute cephalic size (CS) 3.26 mm [2.32, 3.94] (n=22). Cephalic margin with scattered short hairs; cephalic dorsum coarsely reticulate-foveolate. Eye situated on posterior half of the head, PoOC/CL 0.284 [0.242, 0.323]. Frontal carinae sinuate, FR/CS 0.260 [0.209, 0.280], coronal line distinct, antennal scape just surpassing the posterior margin of head by length of one funiculus segment, SL/CS 0.853 [0.711, 1.155]. Anterior margin of clypeus with a rectangular projection, medially straight to slightly convex, ClyL/CL 0.294 [0.269, 0.326]; masticatory margin of mandible with 7-10 teeth, microreticulate at base, becoming finely striolate apically, with scattered piligerous punctures, rarely with a few weak longitudinal rugae near base.

Dorsal outline of mesosoma complex. Promesonotum forms a regular convexity with a shallow impression at the promesonotal suture and is stepped to the propodeal dorsum. Suberect promesonotal setae inclined anteriorly, ML/CS 1.337 [1.168, 1.655]; metanotum distinct; propodeal dorsum almost straight to evenly convex, posterodorsal margin forms rounded angle with declivity.

Petiole higher than broad, node summit flat; brown standing setae present on entire dorsum. PEW/CS 0.221 [0.199, 0.247].

Color: head, mesosoma, petiole, and base of first gastral segment reddish brown, remainder of gaster dark brown to black. Scattered appressed pubescence generally present. Setae light brown.

Distribution and biology.

The minor worker of Camponotus imitator is thought to mimic the myrmicine ant Aphaenogaster swammerdami due to its color and the form of its constricted mesonotum and shape of propodeum, which could appear as a petiole in dorsal view ( Forel 1891) (Fig. 11). This myrmicine nests underground and shares its nests with snakes, Madagascarophis colubrinus (Schlegel, 1837) and Leioheterodon modestus ( Günther, 1863); it is an important secondary seed disperser of Commiphora guillaumini ( Burseraceae ) ( Böhning-Gaese et al. 1999).

Camponotus imitator is distributed in the dry forest and woodland of western and southern Madagascar at elevations ranging from 25 m to 990 m (Fig. 11). Its distribution is sympatric with A. swammerdami through most of its range (Fig. 11). It has been collected by litter sifting, Malaise and pitfall traps, as well as beating low vegetation and from the ground in rotten logs. This species nests underground.

Comment.

We propose that Camponotus imitator resinicola (Santschi, 1911) is synonymized with Camponotus imitator Forel. In the original descriptions, the former differs from the latter by the presence of reddish patches on the first gastral segment near the petiolar insertion. Examination of material from 10 collection events of C. imitator colonies indicates that this trait is highly variable within colonies, and no other reliable characters were found to separate the subspecies from imitator . Moreover, no other qualitative trait or biogeographic evidence exists that would underpin the subspecies status of resinicola.

Additional material examined.

Province Fianarantsoa: Tsaranoro, 32.8 km 230° Ambalavao, -22.08317, 46.774, 975 m, savannah woodland (B.L. Fisher et al.) (CASC); Parc National d’Isalo, Ambovo Springs, 29.3 km 4° N Ranohira, -22.29833, 45.35167, 990 m, Uapaca woodland (Fisher, Griswold et al.) (CASC); Ihosy, -22.40317, 46.12917, 735 m, urban/garden (B.L.Fisher et al.) (CASC); Forêt d’Atsirakambiaty, 7.6 km 285° WNW Itremo, -20. 59333, 46.56333, 1550 m, grassland (Fisher, Gris wold et al.) (CASC). Province Mahajanga: Boeny Region,Distric of Marovoay, Ampijoroa National Park, 160 km North of Maevatanana on RN 04, -16.31933, 46.81333, 42 m, Decidious forest (Rinha, Mike) (CASC); Réserve forestière Beanka, 50.2 km E Maintirano, -18.02649, 44.05051, 250m, tropical dry forest on tsingy (B.L.Fisher et al.) (CASC); Station Forestiere Ampijoroa, -16.31667, 46.81667, 80 m, tropical dry forest (P.S.Ward) (PSWC); Antsalova, -18.68333, 44.61667, 100 m (D. Lees) (PSWC); Parc National Tsingy de Bemaraha, 10.6 km ESE 123° Antsalova, -18.70944, 44.71817, 150 m, tropical dry forest on Tsingy (Fisher-Griswold Arthropod Team) (CASC). Province Toliara: 45km NE Morondava, -20.05, 44.61667, 30 m, tropical dry forest (P.S.Ward) (PSWC); 48km ENE Morondava, -20.06667,44.65,30 m, tropical dry forest (D.M.Olson) (PSWC); Sept Lacs, -23.52472, 44.15917, 160 m, Spiny thicket Gallery forest transition (Frontier Project) (CASC); Forêt de Kirindy, 15.5 km 64° ENE Marofandilia, -20.045, 44.66222, 100 m, tropical dry forest (B.L.Fisher et al.) (CASC); Parc National de Tsimanampetsotsa, Forêt de Bemanateza, 20.7 km 81° E Efoetse, 23.0 km 131° SE Beheloka, -23.99222, 43.88067, 90 m, spiny forest/thicket (Fisher-Griswold Arthropod Team) (CASC); Parc National d’Andohahela, Forêt de Manatalinjo, 33.6 km 63° ENE Amboasary, 7.6 km 99° E Hazofotsy, -24.81694, 46.61, 150 m, spiny forest/thicket (Fisher-Griswold Arthropod Team) (CASC), Parc National d’Andohahela, Forêt de Manatalinjo, -24.82466, 46.60111, 100 m,spiny forest/thicket (Fisher-Griswold Arthropod Team) (CASC); Parc National de Kirindy Mite, 16.3 km 127° SE Belo sur Mer, -20.79528, 44.147, 80 m, tropical dry forest (Fisher-Griswold Arthropod Team) (CASC); Parc National d’Andohahela, Forêt d’Ambohibory, 1.7 km 61° ENE Tsimelahy, 36.1 km 308° NW Tolagnaro, -24.93, 46.6455, 300 m, tropical dry forest (Fisher-Griswold Arthropod Team) (CASC); Forêt de Kirindy, 15.5 km 64° ENE Marofandilia, -20.045,44.66222,100 m, tropical dry forest (Fisher-Griswold Arthropod Team) (CASC); Anosy Region, Distric of Amboasary, 58Km SW of Fort Dauphin, 08 Km NW of Amboasary, Berenty Special Reserve, -25.00667, 46.30333, 85 m, Galery forest ( Rin’ha, Mike) (CASC); Tsihombe, -25.31833, 45.48367, 30 m, urban/garden (B.L.Fisher et al.) (CASC); Forêt Vohidava 89.6 km N Amboasary, -24.23333, 46.30167, 230 m, spiny forest/thicket (B.L.Fisher et al.) (CASC); Forêt de Kirindy, 15.5 km 64° ENE Marofandilia, -20.06855,44.65956667,30 m, tropical dry forest (B.L.Fisher) (CASC); Anosy Region, Distric of Fort-Dauphin, Andohaela National Park Parcelle II, Tsimela,42Km W of Fort-Dauphin, -24.93683, 46.62667, 177 m, transition forest (Michael Irwin, Frank Parker, Rin’ha) (CASC); Forêt de Kirindy, 15.5 km 64° ENE Marofandilia, -20.06915, 44.66041667,30 m, tropical dry forest (B.L.Fisher) (CASC); Atsimo Andrefana Region, Distric of Betioky; Beza Mahafaly Special reserve Parcelle Belle vue 07 Km W of Research Station, -23.68983, 44.5755, 177 m, spiny forest ( Rin’ha) (CASC); Réserve Berenty, -25.01667,46.3,25 m,tropical dry forest (P.S.Ward) (PSWC); Res. Beza-Mahafaly, Parcel 1, -23.65, 44.63333, 130 m, tropical dry forest (P.S.Ward) (PSWC); Makay Mts., -21.31334, 45.14525,575 m, Burned savannah (B.L.Fisher et al.) (CASC). Makay Mts., -21.29961, 45.12919, 570 m, Dry forest edge and burned savannah (B.L.Fisher et al.) (CASC); Makay Mts., -21.22344, 45.3135, 550 m, Gallery forest with bamboo (B.L.Fisher et al.) (CASC); Forêt de Mahavelo, Isantoria River, -24.75833,46.15717,110 m,spiny forest/thicket (Fisher-Griswold Arthropod Team) (CASC); 7.0 km 156° SSE Lavanono,-25.47111,44.9885,50 m,spiny forest/thicket (Fisher-Griswold Arthropod Team) (CASC); 4.4 km 148° SSE Lavanono, -25.45056, 44.97417, 60 m, spiny forest/thicket (Fisher-Griswold Arthropod Team) (CASC); 12.7 km 287° W Marovato, -25.53611,45.15017,130 m, spiny forest/thicket (Fisher-Griswold Arthropod Team) (CASC); 3.5 km 236° SW Marovato, -25.55389, 45.25583, 230 m, spiny forest/thicket (Fisher-Griswold Arthropod Team) (CASC); Réserve Spéciale de Cap Sainte Marie, 12.3 km 262° W Marovato, -25.58167,45.16833,200 m, spiny forest/thicket (Fisher-Griswold Arthropod Team) (CASC); Forêt de Mite, 20.7 km 29° WNW Tongobory, -23.52417, 44.12133, 75 m, gallery forest (Fisher-Griswold Arthropod Team) (CASC); Tsimelahy - Parcel II, Andohahela National Park, transition forest, Tulear Province, -24.93683, 46.62667, 180 m, transition forest (M.E. Irwin, F.D. Parker, R. Harin’Hala) (CASC); Andohaela N. P., Tsimelahy, -24.93683, 46.62667, 180 m, transition forest (M.E. Irwin, F.D. Parker, R. Harin’Hala) (CASC); Ihazofotsy - Parcel III, Andohahela National Park, transition forest, Tulear Province, -24.83483, 46.48683, 80 m, transition between spiny and dry deciduous forests (M.E. Irwin, F.D. Parker, R. Harin’Hala) (CASC);Parcel I, Beza Mahafaly Reserve, near research station, Tulear Province, -23.6865, 44.591, 165 m, dry deciduous forest (R. Harin’Hala) (CASC); Parcel II, Beza Mahafaly Reserve, near Bellevue, Tulear Province, -23.68983, 44.5755, 180 m, spiny forest (R. Harin’Hala) (CASC).