Specimens were deposited in the following collections:

CAS California Academy of Sciences, San Francisco, CA, USA

MHNG Muséum d’Histoire Naturelle, Geneva, Switzerland

MNHN Muséum national d’Histoire naturelle, Paris, France

MSNG Museo Civico di Storia Naturale di Genova “Giacomo Doria”, Genova, Italy

NHMB Naturhistorisches Museum, Basel, Switzerland

PBZT Parc Botanique et Zoologique de Tsimbazaza, Antananarivo, Madagascar

PSWC P. S. Ward Collection, University of California at Davis, CA, USA

ZMHB Museum für Naturkunde, Humboldt-Universität, Berlin, Germany

All morphological observations were made with a Leica MZ9.5 stereomicroscope. We morphometrically investigated 307 individual workers belonging to 215 collecting events for the eleven newly described species and six redescribed species. Camponotus samples were collected across Madagascar by BLF and the Madagascar Biodiversity Center team (Table 1). The material is deposited in the California Academy of Sciences (CAS), San Francisco, USA. Data for all pinned specimens examined in this study are available on the web portal AntWeb (https://www.antweb.org) and can be accessed using their unique identifying specimen code (e.g., CASENT0188388). Images are linked to their specimens via the unique specimen code affixed to each pin. Type material and samples used in the morphometric analysis are given for each species after "Additional material examined" in the following order: Province, locality name, latitude, longitude, elevation (m), habitat, collector and abbreviation of depository. The most common collectors are abbreviated as follows:

BLF BL Fisher and the Madagascar Biodiversity Center team

FGAT Fisher-Griswold Arthropod Team

ARA Andrianjaka Ravelomanana

PSW Phil Ward

MG Madagascar Malaise trap program by Mike Irwin and Rasolondalao Harin’hala Hasinjaka

Digital color montage images were created using a JVC KY-F75 digital camera and syncroscopy Auto-Montage software (version 5.0), or a Leica DFC 425 camera in combination with the Leica Application Suite software (version 3.8). Distribution maps were generated by using QGIS 2.4.0 software (QGIS Development Team 2014).

Measurements were taken with a Leica MZ 9.5 stereomicroscope equipped with a cross-scaled ocular micrometer. Each worker was evaluated using 19 continuous morphometric traits, measured as in Rakotonirina et al. (2016) for the Camponotus edmondi group. The morphometric data are expressed in mm. The following measurements were used (see Figure 1):

CL Maximum cephalic length. The maximum median length of the head in full-face view, measured from the midpoint of the posterior margin of head to the midpoint of the anterior margin of the clypeus (Fig. 1A).

ClyL Clypeal length. The maximum median length of the clypeus measured from the posterior margin to the anterior margin in frontal view, in which the anterior and posterior clypeal margins are aligned to the same focus. Median concavity on either or both margins reduces the length of the clypeus (Fig. 1A).

CS Cephalic size. This derived character is used as a body size indicator and is calculated from the arithmetic mean of head length (CL) and maximum head capsule width (CWb).

CW Maximum cephalic width. The longest distance between the lateral margins of the compound eyes in full-face view (Fig. 1A).

CWb Maximum head capsule width. The maximum width of the head capsule excluding the compound eyes (Fig. 1A).

EL Eye length. Maximum diameter of the compound eye (Fig. 1B).

FR Frontal carina distance. Longest distance between the frontal carina (Fig. 1A).

GPD Maximum tentorial pit distance. The longest distance between the centers of the fossae located at or very close to the posterolateral margin of the clypeus (Fig. 1A).

HTL Maximum hind tibia length. Straight line length of the hind tibia measured from the constriction immediately before its proximal insertion to its distalmost point, excluding the bristles or spines (Fig. 1B).

ML Mesosoma length. The longest anatomical line that connects the posteriormost point of the propodeal lobe with the anteriormost point of the pronotal collar; preferentially measured in lateral view, but if one of the reference points is not visible, dorsal view may help (Fig. 1B).

MPD Mesothoracico-propodeal distance. With the promesonotal suture and the anterior petiolar foramen margin in the same plane of focus in dorsal view, the maximum length between the promesonotal suture and the posteriormost point of the propodeal process dorsal to the petiolar insertion (Fig. 1C).

MPH Mesothoracico-propodeal height. Measured in lateral view, using as a reference the diagonal line that connects the anteriormost point of the pronotal shield and the posteriormost point of the propodeal process dorsal to the petiolar insertion. MPH is the perpendicular distance between two lines parallel to this line, one of which just touches the anteroventral corner of the mesopleuron, dorsal to the insertion of the mesocoxa, and the other which touches the dorsalmost point of the propodeum (Fig. 1B).

MW Mesosoma width. Maximum width of the pronotum in dorsal view (Fig. 1C).

NOH Petiolar node height. The maximum distance between the petiolar spiracle and the dorsalmost point of the petiolar node (Fig. 1B).

OMD Oculo-mandibular distance. The minimum distance between the anterior margin of the compound eye and the mandibular insertion to the head (Fig. 1B).

PEW Petiolar width. The maximum width of the petiole in dorsal view (Fig. 1C).

PoOC Postocular distance. The longest distance between the posteromedian margin of the head and theposterior margins of the two compound eyes. Measured at a right angle to the reference line in full-face view (Fig. 1A).

PrAC Preocular distance. The longest distance between the anteromedian margin of the clypeus and the level of the anterior margin of the compound eyes as a reference line. Measured at a right angle to the reference line in full-face view (Fig. 1A).

SL Scape length. Straight line length of the first antennal segment excluding the basal condyle (Fig. 1B).

TCD Torular carina distance. The minimum distance between the torular arches that surround the antennal insertion (Fig. 1A).

After measuring workers (240 minors and 67 majors), multivariate statistical analysis based on the protocol described by Seifert et al. (2014) and extended by Csősz and Fisher (2016) was performed with data from minor workers only, since Camponotus workers exhibit different forms of allometry. Species hypotheses were generated using the NC-clustering technique (Seifert et al. 2014) via the packages CLUSTER (Maechler et al. 2014) and MASS (Venables and Ripley 2002). The procedure followed Csősz and Fisher (2016) and Rakotonirina et al. (2017, 2018).

Mayria Forel, 1878: 369. [As subgenus of Camponotus Forel, 1894: 227; Bolton, 1994: 50]. Type species: Camponotus repens Forel, 1897: 187, replacement name for Mayria madagascarensis Forel, 1886c: 4, a junior homonym of Camponotus niveosetosus madagascarensis Forel, 1886c: 4].

Mayria as genus Dalle Torre, 1893: 219; Asheamed, 1905c: 384.

Mayria as subgenus of Camponotus Forel, 1894e: 227; Forel, 1914a: 262; Forel, 1927: 251; Wheeler, 1922: 706; Emery, 1925d: 1121; subsequent authors: Bolton, 1995b: 34; Bolton, 2003: 113.

Mayria as junior synonym of Myrmosaga Forel, 1912.

Myrmepinotus Santschi, 1921: 312. [As subgenus of Camponotus]. Type species: Camponotus echinoploides Forel, 189. Syn. nov.

Diagnosis. Workers of the subgenus Mayria are easily distinguished from the other subgenera in Madagascar by the following: postocular distance shorter (PoOC/CL< 0.12); clypeus with short median lobe, its anterolateral corner rounded; anterior margin of pronotum strongly convex in lateral view, forming a rounded flange and extended laterally to form an obtuse humeral angle (Fig. 2A–C); in dorsal view, pronotal disc rectangular with distinct lateral margin (Fig. 2D–F); propodeum dorsum never concave; posterior margin of petiolar node relatively sharp and always surmounted with standing hairs. Body integument opaque, sculptured, and generally matte in color. Standing setae consist of straplike hairs, at least thickened basally (Fig. 2F, G).

Diagnosis of minor worker. Head of minor trapezoidal, broadened posteriorly, lateral cephalic margins slightly convex to straight, occipital margin almost straight to evenly convex (Fig. 2H–J). Mandible short and triangular, armed with six teeth, basal margin forming a smooth curve, not forming a right angle with the mandible insertion. Palp formula: 6, 4. Maxillary palp long. Clypeus transversely trapezoidal with rounded to evenly triangular or rectangular anterior margin, anterolateral portion always rounded, posterior margin of clypeus straight. Antennae 12-segmented: moderately long, scape gradually broadened apically. Frontal lobe narrowed anteriorly, wider behind the antennal insertion; frontal carina V-shaped. Compound eye moderately sized, protruding, breaking the outline of the lateral cephalic margin in alamaina species group, located posterior to the midlength of the head.

Mesosoma in lateral view, dorsal outline of mesosoma continuous (darwinii group) to complex (other groups). Promesonotal suture visible. Pronotum: humeral angle tuberculate (C. ellioti species group), marginate in the remaining species group; in dorsal view, pronotal disc usually rectangular. Mesonotum in dorsal view, wider than long; laterally marginate in C. edmondi species group. Mesopleuron and propodeal surface together distinctly longer than lateral portion of pronotum in lateral view. Propodeal lobe reduced. Metapleural gland absent. Procoxa of normal to moderate size for C. edmondi species group. Middle and hind tibiae with single pectinate spur.

Petiolar node: broad and massive, ranging from squamiform to nodiform, posterodorsal edge of petiole always marginate and ornamented with thick, erect hairs.

Integument opaque and sculptured, ranging from finely and densely reticulate-punctate to finely and densely imbricate.

Pilosity: standing setae thick at least at the base, whitish to pale colored, erect to appressed hairs, filiform to spatulate hairs, moderately distributed on entire dorsum of head and body; ground pilosity always present and conspicuous.

Diagnosis of major worker. Most of the morphological traits cited above for minor workers are also characteristics of major workers. However, major workers exhibit the following characters: head more subquadrate to rectangular; malar area thimble-like with weak impression at the base of each seta (Fig. 2K–M); lateral portion of head sculptured as finely and densely reticulate-punctate, imbricate, or areolate, and superimposed with two to seven smaller areoles embedded in scattered large punctures, from which an appressed hair arises medially; antennal scape shorter, its apex barely surpassing or not extending beyond posterior cephalic margin; dorsal outline of mesosoma with the same structure as minor worker.

Note. The type species Camponotus echinoploides of the subgenus Myrmepinotus shares the characters of the Mayria diagnosis and therefore Myrmepinotus is synonymized with Mayria. The following characters place C. echinoploides within the Mayria subgenus: in dorsal view, mesosoma relatively short and distinctly marginate anteriorly and laterally; pronotum and mesonotum widened; promesonotal and metanotal sutures well marked; in profile, petiolar node thick with convex anterior and posterior margins, and body covered with whitish, thick hairs. In fact, the lectotype of C. repens and the holotype of C. echinoploides share a suite of morphological characters: in full-face view, head elongate, broadened posteriorly with slightly convex sides; clypeus with short median lobe; in profile, anterior margin of pronotum strongly convex; pronotal disc subrectangular, marginate laterally; petiolar node as high as long; standing setae consist of thick, whitish hairs; body integument dull. These morphological characters are observed also in specimens belonging to the edmondi species group but absent for species that are removed from the subgenus Mayria (Table 2). Accordingly, we have treated Myrmepinotus as a synonym of Mayria.

alamaina species group:

alamaina Rakotonirina, Csősz & Fisher, 2016

androy Rakotonirina, Csősz & Fisher, 2016

bevohitra Rakotonirina, Csősz & Fisher, 2016

antsaraingy species group:

antsaraingy sp. nov.

darwinii species group:

darwinii Forel, 1886

= Camponotus darwinii var. rubropilosus Forel, 1891: 44. syn. nov.

= Camponotus darwinii r. rubropilosus var. robustior Forel, 1905: 165. syn. nov.

norvigi sp. nov.

nossibeensis André, 1887

radovae Forel, 1886

= Camponotus radovae darwinii Forel, 1891: 46. syn. nov.

themistocles Forel, 1910, stat. nov.

ursus Forel, 1886

edmondi species group:

echinoploides Forel, 1891

edmondi André, 1887

= edmondi var. ernesti Forel, 1891 syn. nov.

galoko Rakotonirina, Csősz & Fisher, 2016

matsilo Rakotonirina, Csősz & Fisher, 2016

mifaka Rakotonirina, Csősz & Fisher, 2016

orombe Rakotonirina, Csősz & Fisher, 2016

tafo Rakotonirina, Csősz & Fisher, 2016

tratra Rakotonirina, Csősz & Fisher, 2016

varatra Rakotonirina, Csősz & Fisher, 2016

zavo Rakotonirina, Csősz & Fisher, 2016

efitra species group:

chrislaini sp. nov.

efitra Rakotonirina, Csősz & Fisher, 2017

ellioti species group:

andrianjaka sp. nov.

ellioti Forel, 1891

maintikibo Rakotonirina, Csősz & Fisher, 2017

maintilany sp. nov.

madagascarensis species group:

descarpentriesi Santschi, 1926

ivadia sp. nov.

madagascarensis Forel, 1886

mita Rakotonirina, Csősz & Fisher, 2017

voeltzkowii Forel, 1894

repens species group:

jjacquia sp. nov.

claveri sp. nov.

repens Forel, 1897

ihazofotsy sp. nov.

tsimelahy sp. nov.

robustus species group:

ethicus Forel, 1897

robustus Roger, 1863

zoro sp. nov.

Minor worker: in full-face view, head subovate, distinctly longer than broad, lateral margin more or less straight and rounding to the broadly convex posterior margin (Fig. 3A). Anteromedian margin of clypeus generally convex; posteromedian margin slightly notched.

Major worker: in full-face view, head subquadrate, posterior margin approximately straight and rounding to lateral margins. Clypeus hexagonal, its anterior border straight and medially excised, frontal triangle distinct (Fig. 3C).

Minor and major workers: Mesosomal profile almost flattened and interrupted by the impressed metanotal suture. Promesonotal dorsum flattened; anterodorsal angle of pronotum and dorsolateral portion of mesosoma bluntly marginate; posterolateral margin of propodeum rounding to declivitous surface (Fig. 3B–D). In dorsal view, mesonotum as long as broad, but sides converging posteriorly; mesonotum and propodeum laterally compressed at their junction; metanotal groove vestigial, represented by a transverse line. In profile, petiolar node anteroposteriorly flattened and tapered dorsally; anterior margin slightly convex and posterior margin more or less straight; dorsal margin straight or weakly excised medially (Fig. 3D). Dorsum of head, mesosoma, and petiole with imbricate sculpture; gaster with finer imbrication; mandible coriarious-puncticulate. Pairs of erect hairs transversely arranged on mesosomal dorsum and in a row on gastral tergite, pubescence short and scattered on dorsum of body.

Remarks. The group is distinguishable from all other members of the subgenus Mayria by the combination of the following characters: mesosoma distinctly marked with promesonotal and metanotal sutures; petiole with sharp edge, its anterior margin convex and its posterior margin more or less straight; propodeal spiracle placed anterior to posterolateral margin of propodeum; head and mesosoma black to dark brown, gaster and appendages dark brown to yellow or depigmented yellow; cervical shield joining pronotal dorsum directly; junction of dorsal face to lateral face of propodeum without sharp carina, posterolateral margin present.

Even though Rakotonirina et al. (2016) described these three species as members of C. edmondi species group, these character states justify a different grouping. In addition, species of this group prefer arid habitats such as dry forest, spiny bush and thicket, and gallery forest, with the exception of Camponotus bevohitra, which can be found in montane rainforest.

Minor worker: in full-face view, head subtriangular, longer than wide, with arched posterior margin and straight lateral sides. Clypeus with projecting triangular lobe (Fig. 4A).

Major worker: in full-face view, head large, about as broad as long, with slightly convex posterior and lateral borders. Anterior margin of clypeus forming a rounded lobe (Fig. 4C).

Minor and major workers: antennal scape entirely flattened longitudinally. In lateral view, mesosoma short and high, propodeal dorsum relatively shorter than declivitous face. Suberect spatulate hairs present on occipital portion until anterior margin of eyes and on clypeal dorsum, pubescence long and distinct, moderately abundant next to antennal insertion. Body massive, black throughout. In lateral view, petiole cuneiform, with sharp dorsal margin. Body integument matte black, finely and densely reticulate-punctate. Dorsum of mesosoma and gaster covered with numerous spatulate, whitish hairs (Fig. 4B, D).

Remarks. Camponotus antsaraingy is placed in its own group, based mainly on the following characters: its large size, the shape of its antennal scape, propodeum distinctly reduced, its dorsum covered with erect spatulate setae, and having only three gastral tergites visible in dorsal view. It is one of the groups in the subgenus Mayria with white pilosity. It differs from the madagascarensis species group by the structure of its mesosoma and its larger size.

Minor worker: in full-face view, head more or less rectangular, with convex lateral sides and evenly straight occipital margin. Setae on dorsum of head sparsely distributed on occipital portion, arranged in longitudinal row along frontal carina (Fig. 5A).

Major worker: in full-face view, head somewhat longer than broad, a little narrower in front than broad (Fig. 5C).

Minor and major worker: clypeus with short, truncated, or rounded rectangular median lobe, its dorsum covered with randomly spaced setae. Mesosomal profile continuous, promesonotal and metanotal suture not impressed, sometimes forming a shiny line. Petiole scale usually not thick, but thin or sharp along margins. Integument opaque, matte black or brown, distinctly reticulate-punctate throughout. Body mostly covered with coarse yellow, red, or white setae, sometimes forming a dense fur coating the gaster or mesosoma (Fig. 5B, D).

Remarks. Camponotus darwinii species group has consistently been considered a distinctive group because of the presence of coarser and denser pubescence on its dorsal margin; integument dull and sculptured; dorsal outline of mesosoma continuous. This group is distinguishable from all other members of the subgenus Mayria by the presence of dense, whitish pilosity on its dorsum and the arcuate profile of its mesosoma. Species in this group are traditionally classified under subgenus Myrmopiromis, type species Camponotus fulvopilosus, type location South Africa. The subgeneric definition by Emery (1925) and the revised definition of Camponotus fulvopilosus species group by Robertson (1990, 1997) are quite different from Camponotus darwinii species group. In addition to the species distribution, the number of mandibular teeth is a good character for distinguishing these two species groups: six for C. darwinii group and seven or eight for C. fulvopilosus group.

Minor worker: in full-face view, head as long as broad, posterior margin broadly convex, lateral margins roughly straight (Fig. 6A).

Major worker: in full-face view, head subquadrate, posterior and lateral margins more or less straight to convex (Fig. 6C).

Minor and major: clypeus with broadly convex anterior margin and medially notched posterior margin. In profile, dorsal outline of mesosoma interrupted by metanotal suture, promesonotal suture distinct but not impressed. In profile, petiole always biconvex. Body integument opaque, densely reticulate-punctate (Fig. 6B–D). Few scattered hairs present on mesosomal dorsum, pubescence abundant to reduced.

Remarks. The Camponotus edmondi species group can be distinguished by the combination of the following characters: dorsolateral margin of propodeum marginate or extending into a sharp ridge, propodeal declivity usually concave, anterolateral corner of pronotum most often marginate, forecoxa larger than the width of mesopleuron, and propodeal dorsum abruptly sloping down to the insertion of the petiole.

Minor worker: in full-face view, head subovate with strongly convex posterior and lateral sides. Anterior clypeal margin broadly rounded (Fig. 7A).

Major worker: in full-face view, head roughly quadrate or rectangular, head sides evenly convex (as in C. efitra) to straight (as in C. chrislaini) (Fig. 7C).

Minor and major: in profile, metanotal suture impressed, the propodeal dorsum forming a separate convexity from a domelike promesonotum, dorsum of propodeum below level of promesonotum. Clypeus evenly convex to straight in profile, its anterior margin convex to broadly triangular, not projecting, posterior margin weakly notched medially, major worker with massive mandible, occipital portion asetose, few standing setae present between frontal carinae but moderately present on clypeal dorsum and malar area. Petiole nodiform. Color brown. Integument sculpture finely imbricate to glabrous, apparently shiny (Fig. 7B, D).

Remarks. The efitra group is characterized by the color and sculpture of its integument; and a convex promesonotum separated from the propodeum by a weak metanotal suture. In Rakotonirina, Csősz & Fisher, 2017, C. efitra was considered a member of the grandidieri species group. Here, this species is separated from this group by the form of the mesosoma and the petiolar scale, the type of integument, and the general sculpture of major workers.

Minor worker: in full-face view, head subtriangular, posterior margin evenly convex, head sides anterior to eyes subparallel and diverging posteriorly (Fig. 8A).

Major worker: in full-face view, head longer than broad, subtriangular to rectangular; with weakly convex sides (Fig. 8C).

Minor and major: anterior margin of clypeus of minor worker rounded and triangular, with anterolateral corner right-angled for C. maintikibo. Pronotum sometimes narrowly rounded or shouldered (C. ellioti, C. maintikibo) (Fig. 8B). In profile, dorsal outline of mesosoma evenly convex (C. ellioti, C. maintikibo) or slightly concave at the level of metanotal suture (C. andrianjaka) (Fig. 8D) or with impressed metanotal suture (C. maintilany). Humeral angles of pronotum well-marked. Petiole squamiform to nodiform. Integument finely imbricate to coarsely reticulate-foveolate. Pubescence long and distinct, few pairs of standing hairs on vertex.

Remarks. The Camponotus ellioti species group is characterized by the following morphological features: mesosoma reddish, gaster dark brown to black; anterior clypeal margin projecting into broadly convex lobe; frontal carina short and diverging posteriorly, median carina absent; clypeus with short, rounded lobe; mandible subtriangular, apical tooth long; eyes large, elliptical, and break the lateral margin of head; in minor, head and occipital margin rounded, lateral head sides parallel before eyes.

Camponotus ellioti has been considered a member of subgenus Myrmopiromis mainly because of the dense pilosity on its gastral dorsum and the humeral angle, but after morphological investigation, we find that the color of the integument can be a good indicator for separating Malagasy Camponotus species.

Minor worker: in full-face view, head elongate, lateral borders straight, feebly diverging posteriorly; posterior margin more or less convex (Fig. 9A).

Major worker: in full-face view, head rectangular, posterior and lateral borders slightly convex (Fig. 9D).

Minor and major worker: with the head in full-face view, anterior clypeal margin with an angular lobe, triangular or rectangular with rounded anterolateral angle; clypeus with median carina. In profile, dorsal line of mesosoma forms a continuous line, anterolateral corner of pronotum rounded. Petiolar node compressed anteroposteriorly and tapering dorsally; anterior face generally convex and posterior face straight. Posterior portion of the head, mesosomal dorsum, and the lateral margin of the propodeal declivity with scattered, whitish, erect hairs (Fig. 9B, D).

Remarks. The Camponotus madagascarensis species group possesses the same characters as the Camponotus niveosetosus group, described in Rakotonirina et al. (2017); the name has been changed because these species are endemic to Madagascar. This group is morphologically well defined by the distinctive disposition of hairs on the gastral segment. Four species of this group, with the exception of C. ivadia, are historically recognized as members of subgenus Myrmopiromis. In this study, we conclude that C. madagascarensis are endemic to the Malagasy region, while C. niveosetosus, the most similar species, is from South Africa and possesses the following suite of different morphological characters: occipital margin almost straight and not distinctly convex so that the anterior margin of pronotum is distinctly roof-like in dorsal view, cuticle of the dorsum of head of major worker with distinctive sculpture pattern, mandible of major worker with seven teeth.

Minor worker: in full-face view, head oval, with broadly convex posterior margin and lateral sides almost straight (Fig. 10A).

Major worker: in full-face view, head rectangular, posterior and lateral margins weakly convex (Fig. 10C).

Minor and major: with head in full-face view, clypeus carinate medially, its anterior margin forming a triangular lobe except for C. repens, which has a truncate anteromedian margin; dorsum of body covered with numerous slender, whitish, erect hairs and abundant, elongated pubescence. In lateral view, pronotum weakly convex with anterolateral portion marginate; promesonotal suture slightly depressed (Fig. 10B, D). Petiole nodiform except C. claveri. Head, mesosoma, and gaster black; legs generally much lighter in color than body. Integument shiny black.

Remarks. Workers of the C. repens group can be diagnosed by the integument being black and shiny in appearance, and the presence of erect white setae along the entire dorsum, all of which are about the same length and transversely arranged, except in C. jjacquia, which has filiform and relatively medium-sized setae. Median portion of clypeus with longitudinal carina; dorsum of mesosoma covered with numerous, slender, erect hairs of about the same length; in lateral view, petiolar node higher than long. Metanotal spiracle obvious, surrounded by shallow depression, not as in C. christi species group. The best method to discriminate between the Camponotus repens species group and all other species stated in the Rakotonirina et al. (2018) Camponotus christi species group, is to compare the anterodorsum of pronotal margin and the mesosomal pilosity. In the C. repens group, in dorsal view, the pronotal disc is rectangular and pilosity consists of thick, whitish, erect hairs. By contrast, in the C. christi group, in dorsal view, the pronotal disc is semicircular, and pilosity consists of slender, filiform hairs.

Minor worker: in full-face view, head longer than broad, lateral margins nearly straight and slightly diverging posteriorly, posterior margin broadly convex (Fig. 11A).

Major worker: in full-face view, head broader than long, lateral margin slightly convex (Fig. 11C).

Minor and major worker: clypeus not produced but with a rounded anterior margin. In profile, dorsal outline of mesosoma roughly straight and broken by metanotal suture (Fig. 11B, D); mesonotum and propodeum dorsum mostly rectangular and flattened in profile view. Ant black with opaque integument, pilosity suberect and white, pubescence short but distinct.

Remarks. The Camponotus robustus species group can be distinguished by the combination of the following characters: in profile, posterodorsal face of petiole flat; anterodorsal margin of pronotum not arcuate, as in C. edmondi species group, but with broadly rounded to tuberculate humeral angle. In dorsal view, propodeum dorsum rectangular with distinct lateral margin; it forms an obtuse angle with the declivitous face. Clypeus with short anterior rounded lobe, sometimes notched medially (C. ethicus). Mesosomal dorsum complex, metanotal suture impressed. This group includes three species, two of which have been previously described as part of the C. edmondi species group. However, from Rakotonirina et al. (2016), this group can be recognized with the combination of the following characters: dorsolateral margin of propodeum marginate or extending into a sharp ridge, propodeal declivity usually concave, anterolateral corner of pronotum most often marginate, forecoxa larger than the width of mesopleuron, and usually propodeal dorsum abruptly sloping down to the insertion of the petiole. In addition, this species group has a prominent pronotal suture which is large and arcuate, making the characteristic form of mesonotum oval in dorsal view; propodeum dorsum mostly reduced in length and inclined towards petiole; and petiolar face distinctly convex, with at least one face, in dorsal view, resembling a handheld fan. C. ethicus and C. robustus are now placed with Mayria and form a monophyletic group with Camponotus zoro based on the morphological traits cited above.

Descriptions of the three species are illustrated in Rakotonirina et al. (2016): Camponotus alamaina Rakotonirina, Csősz & Fisher, 2016 on pp. 105–110, Camponotus androy Rakotonirina, Csősz & Fisher, 2016 on pp. 110–113, and Camponotus bevohitra Rakotonirina, Csősz & Fisher, 2016 on pp. 113–115.