Odontomachus allolabis Kempf, 1974: 551

França, Eder Cleyton Barbosa, Fernandes, Itanna Oliveira & Bravo, John Edwin Lattke, 2024, Looking at upside-down ants: Taxonomic revision of the Neotropical species of Odontomachus Latreille, 1804 (Hymenoptera: Formicidae: Ponerinae), Zootaxa 5502 (1), pp. 1-166 : 44-55

Odontomachus allolabis Kempf, 1974: 551 (♀).

Type material: Holotype. Odontomachus allolabis Kempf, 1974 ; [ BRAZIL]: Acre, Cruzeiro do Sul , xii.1963, P. L. [Luiz] Herbst [col.], CSSp., 9116, MZSP77594 1♀ [ MZSP].

Etymology: Combination of the Greek words allos = other + the Latin word labium = lip; referring to the two mandibular apical teeth, which are different from the other species.

Diagnosis: (☿) Body light brown to yellowish. Vertex smooth and shining. Pronotum longitudinally striate. Mesopleuron without anteroventral rounded carina or rounded lobes. Petiolar node conical, gradually tapering into short spine, acute and curved posteriorly; nide with round posterolateral projection. Gastral terga smooth and shining. (♀) Vertex, mesopleuron and petiolar node as worker. Pronotal striae on lateral face longitudinal, not arching. Mesoscutum, axilla and mesoscutellum smooth and shining. (♂) Unknown.

Worker

Non-type measurements: EL 0.4, HL 2.1, HoW 1.6, HvW 1.2, HW 1.4, ML 1.3, SL 2.3, PnW 1.0, WL 3.0, FL 2.3, PTH 1.0, PTL 0.5, PTW 0.5, GL 2.4, TL 9.3. CI 0.66, MI 0.61, PtI 0.26, SI 1.09, VI 0.85 (n= 1).

Head. Vertex trapezoidal, wider than long in frontal view; smooth and shining. Posterior margin medially concave; occipital carina not forming nuchal collar. Cephalic constriction conspicuous. Frontal lobes smooth and shining. Ocular bridges posteriorly forming arc. Eye relatively large (EL> 0.4); rounded, posterior margin rounded. Clypeus smooth and shining medially. Malar area smooth and shining in latero-oblique view.

Mandible. Almost as long as anterior head portion. External margin straight. Masticatory margin with blunt denticles, serially increasing in size, apical denticle two times larger than the anterior. Palp formula 4,3.

Antenna. Scape surpassing occipital corner by 2x pedicel length.

Mesosoma. Pronotum in lateral view rounded, dorsal margin convex; neck well developed anteriorly in dorsal view; lateral margin rounded; central disc of pronotum longitudinally striate, forming concentric arcs anteriorly. Propleuron smooth and shining. Mesonotum wider than longer; transversely striate, striae slightly effaced medially. Mesopleuron in dorsal view, without rounded carina or lobe on anteroventral portion; mostly smooth and shining. Mesometanotal sulcus well-marked, scrobiculate. Metanotum as long as notopropodeal sulcus and lower than propodeum level; with weak rugulae. Metapleural gland bulla with inconspicuous transverse striae on dorsal portion. Propodeum almost straight in lateral view with slight anterior convexity; posterior margin length about 1/3 of dorsal length. Metasternum with metasternal process vestigial, formed by two fine, posteriorly converging striae; with very fine transverse striae, laterally effaced.

Petiole. Sessile. Node conical, anterior margin straight in lateral view, node gradually tapering into petiolar spine. Spine short, acute, slightly curved posteriorly. Posterior face of petiolar node rounded and projecting laterally, middle portion concave. Smooth and shining. Subpetiolar process wider than long, keel-shaped; tip acute; posterior portion concave.

Gaster. First tergum almost higher than long in lateral view; anterior and dorsal margins form obtuse angle; dorsal face convex; dorsal face smooth and shining.

Color and size. Body light brown to yellowish. Legs and antennae pale yellow. Relatively small ants.

Pilosity. Scattered, conspicuous and short pubescence spread over body, hairs separated from each other by about 2x their length. Pubescence on lateral margin of mandible denser than on body surface. Petiole with pubescence on anterior face extending to lateral face. Hairs on anterior pro-coxal face shorter than pro-coxal width. Pronotum and gastral terga with several long, curved erect hairs, longer than maximum pro-coxa width. Relative long erect hairs on anterior face of petiolar node.

Gyne

Holotype measurements: EL 0.44, HL 1.88, HoW 1.64, HvW 0.93, HW 1.02, ML 1.09, SL without scapes, PnW 1.03, WL 2.7, FL 1.4, FWL without wings, PTH 0.95, PTL 0.62, PTW 0.5, GL 3.21, TL 9.5. CI 0.54, MI 0.57, PtI 1.53, VI 0.91.

Non-type measurements: EL 0.4, HL 2.1, HoW 1.7, HvW 1.2, HW 1.4, ML 1.3, SL 2.1, PnW 1.1, WL 3.1, FL 2.3, FWL without wings, PTH 1.2, PTL 0.6, PTW 0.6, GL 3.1, TL 10.2. CI 0.76, MI 1.23, PtI 2.0, SI 0.64, VI 1.07 (n= 1).

Mesosoma. Pronotum longer than high in lateral view, dorsal margin concave almost forming obtuse angle; lateral margins converging anteriorly forming a neck in dorsal view; pronotal dorsum with transverse and posteriorly convex striae, striae longitudinal on lateral face becoming irregular posteriorly. Subalar area continuous to pronotum; rugulose. Mesoscutum anterior and dorsal margins form single convexity in lateral view; smooth and shining in dorsal view; effaced striae between parapsidial line and parascutal area oblique, directed medially. Parapsidial line curved, well-marked. Parascutal area smooth and shining. Notopropodeal sulcus scrobiculate. Axilla smooth and shining. Mesoscutellum smooth and shining, with sparse piligerous puncture, without longitudinal carina. Metascutellum with blunt longitudinal carinae; smooth and shining.

Petiole. Petiolar node conical, anterior margin straight, gradually tapering into spine in an obtuse angle. Posterior portion of petiolar node rounder than in worker. Spine longer than in worker.

Pilosity. Pubescence on mesosoma strongly curved, dense, hairs separated from each other less than their length. Pubescence on petiole and gaster straight, thin and appressed. Pronotum and dorsal portion of petiolar node with short relatively thin hairs, length less than procoxa width. Gaster hairs denser than pronotum, suberect and curved posteriorly.

Natural history: Little is known about this species. The holotype and the paratype were collected as prey of Eciton rapax Smith, 1855 ( Kempf, 1974). The gyne from Yasuní was sampled with a Berlese funnel. This species probably has cryptic habits that can explain such a lack of records. This species seems to be distributed in Amazonian regions relatively close to the Andes ( Fig. 51 ).

Comments: Gynes of O. allolabis share the smooth and shining vertex, the shining gastral terga, the irregular pronotal striae, and the yellowish body color with the gynes of O. panamensis . The gynes of O. allolabis can be differentiated by the presence of longitudinal striae on the lateral of the pronotum, the smooth and shining pterothorax, and the strong convexity of the node posterior face. In contrast, the lateral pronotal face of O. panamensis has arched striae, the pterothorax has conspicuous longitudinal striae, the mesopleuron has rounded lobes on the anterior ventral portion, and the posterior node face is not as convex as in O. allolabis . The workers also can be recognized by the pronotal striae, the petiolar node, and the anterior ventral portion of the mesopleuron. The striae on O. allolabis form longitudinal concentric arcs close to the neck and the mesopleuron does not have any projection, while in O. panamensis the pronotal striae mostly form acute angles anteriorly, and the mesopleuron has rounded lobes anteriorly.

In the original description of O. allolabis, Kempf (1974) , mentions that the type specimens have traits in common with specimens parasitized by nemathelminths, such as the narrowed posterior portion of the head and physogastry ( Fig. 53 ). He dissected the holotype’s gaster ( Fig. 53-C ) to search for a possible parasite and did not find any. Hence, he considered the narrow vertex and mandible with two apical teeth as enough to recognize O. allolabis as a new species. No other Odontomachus species have only two apical teeth, even specimens parasitized. Currently, only the holotype and the paratype of O. allolabis are known with such morphology, despite numerous samplings for ants close to the type-locality in Acre ( Schmidt et al. 2020). This reduction of apical teeth number is possibly caused by a specific parasite species and perhaps due to this, it has not been observed in the other cases.

A worker (MEPN33334) and gyne (MEKOU176262-11) similar to O. panamensis , were found in the MEPN collection and initially determined as new species. Both specimens have the petiolar node completely smooth and shining and its posterior margin is very convex, expanding laterally; the metasternum does not have a process, just a pair of thin lateral striae and the mesopleuron does not have rounded lobes on the anterior ventral portion. The worker has longitudinal pronotal striae and the outer striae do not form concentric arcs. In the gyne, the pronotal striae are longitudinal on the lateral face, and the mesonotum, mesoscutellum, and axilla are smooth and shining. These characters match the pterothorax and petiole of O. allolabis , but the mandibles of both individuals have three apical teeth, with the dorsalmost tooth from the masticatory margin being the largest and standing out from the others. No other gyne of Odontomachus in the Neotropical region has a such combination of characters and the stability of the metasternal process shape between castes supports the identity of the studied worker as O. allolabis . In addition, the pronotal sculpturing and the petiolar node shape is unique among all Odontomachus workers.

Material examined: ECUADOR: Morona Santiago: Cordillera del Cutucú, Reserva Privada de Wisui (1☿) . Orellana: Río Huiririma, Est. [Estación] Chiruisia-Petrobrás (1☿) . Sucumbíos: Parque Nacional Yasuní, Estación Científica Yasuní (1♀) .

Odontomachus bauri Emery, 1892 ( Figures 6-C, F, J, M , 7-D , 15-B , 20-B , 24-B , 26-B , 36-B , 37-B , 46-B , 47-A , 55 , 56 , 57 and 58 )

Odontomachus bauri Emery, 1892: 561 (☿ diagnosis in key); Emery, 1893: 90 (☿); subspecies of Odontomachus haematodus by Emery, 1911: 115; status as species by Taylor & Wilson, 1961: 142; subspecies of Odontomachus haematodus by Kempf, 1972: 171; status as species by Brown, 1976: 102, 129.

Odontomachus haematodus var. pubescens Roger, 1861: 25 (☿ in text); status as species by Dalla Torre, 1893: 52; subspecies of Odontomachus haematodus by Emery, 1894: 146; status as species by Forel, 1895a: 64; status as subspecies of Odontomachus haematodus by Forel, 1899: 21; junior synonym of Odontomachus bauri by Brown, 1976: 102.

Odontomachus haematodus var. microcephalus Emery, 1890: 45 (☿); junior synonym of Odontomachus haematodus by Forel, 1899: 20; junior synonym of Odontomachus bauri by Brown, 1976: 102.

Odontomachus haematodus var. paucidens Emery, 1893: 91 (☿); Menozzi & Russo, 1930: 151 (♂); junior synonym of Odontomachus bauri by Brown, 1976: 102.

Odontomachus sericeus Provancher, 1895: 97 (♀); junior synonym of Odontomachus bauri by Brown, 1976: 102.

Odontomachus haematodus var. rugisquama Forel, 1908: 35 (☿); Forel, 1912: 28 (♀); junior synonym of Odontomachus bauri by Brown, 1976: 102.

Odontomachus haematodes var. notata Mann, 1920: 404 (☿); junior synonym of Odontomachus bauri by Brown, 1976: 102.

Type material: Holotype [Images]. Odontomachus bauri Emery, 1892 ; [ ECUADOR: Galapagos Islands], Albemarle [now Isabela Island], Baur [G. col.], 1891, (unreadable), [Among tortoise carapaces], CASENT094010 1☿ [ MSNG].

Syntype [Images]. Odontomachus haematodus var. paucidens Emery, 1893 ; HAITI: [No further data], Linbe [Limbé], CASENT0904011 1☿ [ MSNG] .

Syntype [Images]. Odontomachus haematodes var. rugisquama Forel, 1908 ; COSTA RICA: [La Caja near] San José, (unreadable), Biolley [col.], Coll. Forel, [Santa Clara plain, tree trunks], CASENT0907434 1☿ [ MHNG] .

Etymology: In honor to Georg Baur (1859-1898), a German vertebrate paleontologist who studied Galápagos tortoises and collected the type specimens of this species.

Diagnosis: (☿) Propleuron smooth and shining. Metasternum with coarse regular transverse striae; metasternal process close and bilobate. Petiole sessile, node campanulate to conical with coarse transverse striae reaching posterior face. Body color dark brown, almost black. (♀) Propleuron, metasternal process and petiolar striae as in worker. (♂) Mesosoma with light brown spots on parapsidial lines. Propodeum dark brown with coarse rugae. Metasternal process close and bilobate.

Worker

Holotype measurements: EL 0.39, HL 2.4, HoW 1.9, HvW 1.45, HW 1.64, ML 1.11, SL 2.31, PnW 0.99, WL 2.9, FL 2.37, PTH 1.02, PTL 0.5, PTW 0.4, GL 2.36, TL 9.54. CI 0.68, MI 0.46, PI 2.04, SI 0.96, VI 0.88.

Non-type measurements: EL 0.4-0.5, HL 2.3-3.0, HoW 1.8-2.3, HvW 1.3-1.9, HW 1.6-2.1, ML 1.1-1.7, SL 2.2-2.9, PnW 1.1-1.3, WL 2.8-3.9, FL 2.3-3.1, PTH 0.9-1.5, PTL 0.5-0.7, PTW 0.4-0.6, GL 2.1-3.7, TL 9.0-12.6. CI 0.65-0.74, MI 0.40-0.61, PI 1.80-2.50, SI 0.86-1.03, VI 0.81-0.90 (n= 30).

Head. Vertex trapezoidal, wider than long in frontal view; with regular longitudinal striae diverging and effacing posteriorly, reaching posterior margin. Posterior margin concave medially; occipital carina not forming nuchal collar. Cephalic constriction conspicuous. Frontal lobes striated. Ocular bridges posteriorly forming arc. Eye relatively large (EL> 0.4); rounded, posterior margin rounded. Clypeus with irregular inconspicuous oblique to longitudinal striae on median portion. Malar area wrinkly-punctate on anterior portion in latero-oblique view, posterior portion smooth and shining.

Mandible. Almost as long as anterior head portion. External margin slightly convex. Masticatory margin with blunt denticles that serially increase in size apically. Palp formula 4,3.

Antenna. Scape surpassing occipital corner about pedicel half-length or less.

Mesosoma. Pronotum in lateral view rounded, dorsal face convex; neck well developed anteriorly in dorsal view; lateral margin rounded; central disc of pronotum with regular longitudinal striae forming different shapes, lateral striae forming concentric circles. Propleuron smooth and shining; regular fine oblique striae restricted to anterior portion gradually fading posteriorly. Mesonotum wider than long; with regular transverse striae slightly curved anteriorly. Mesopleuron with rounded carina on anteroventral portion; anterior portion with regular transverse striae curved dorsal-anteriorly; median portion smooth and shining; posterior portion with regular transverse striae slightly inclined posteriorly. Mesometanotal sulcus well-marked, scrobiculate. Metanotum vestigial. Metapleural gland bulla with transverse striae effacing posteriorly. Propodeum in lateral view straight; posterior margin length about 1/3 of dorsal length. Metasternum with metasternal process close, cuticle border forming bilobate projections; with regular transverse coarse striae.

Petiole. Sessile. Node campanulate to conical, anterior margin usually continuous with petiolar spine. Spine acute, straight or curved posteriorly. Coarse, regular to irregular transverse striae covering all surface, coarser on ventral portion. Subpetiolar process wider than long keel-shaped; tip acute; posterior portion concave.

Gaster. First tergum almost higher than long; anterior and dorsal margin meeting in an obtuse angle; dorsal face convex; dorsal face of all terga strongly to slightly imbricate, almost smooth and shining.

Color and size. Body dark brown almost black. Legs and antennae brown to yellowish. Relatively medium size ants.

Pilosity. Hook-shaped, scattered, conspicuous and short pubescence spread over the body, separated each other about their length. Pubescence on mandible sparser than body surface. Pubescence on petiole limited to anterior face extending to lateral faces. Short hairs on anterior portion of pro-coxa smaller than coxal width. Pronotum with three or four pairs of long, curved erect hairs longer than maximum pro-coxal width. Posterior 2/3 of gastral terga hairs directed posteriorly, as long as pronotum hairs.

Gyne

Non-type measurements: EL 0.40-0.60, HL 2.50-2.80, HoW 2.00-2.30, HvW 1.60-1.90, HW 1.90-2.00, ML 1.40- 1.60, SL 2.20-2.70, PnW 1.40-1.50, WL 3.20-4.00, FL 2.40-2.90, FWL 7.10-7.60, PTH 1.30-1.70, PTL 0.50-0.80, PTW 0.60-0.70, GL 3.40-4.10, TL 11.60-12.90. CI 0.67-0.76, MI 0.53-0.59, PtI 2.12-2.66, SI 0.88-1, VI 0.8-0.95 (n= 10).

Mesosoma. Pronotum slightly longer than high in lateral view, dorsal margin slightly concave; lateral margins converging anteriorly forming a neck in dorsal view; with regular transverse striae forming arcs directed posteriorly on lateral face. Subalar area conspicuous with pronotum. Mesoscutum anterior and dorsal margin forming single convexity in lateral view; with regular longitudinal striae in dorsal view; striae between parapsidial line and parascutal area oblique, directed medially. Parapsidial line straight, well-marked. Parascutal area smooth and shining. Notopropodeal sulcus scrobiculate. Axilla with effaced longitudinal striae anteriorly, smooth and shining posteriorly. Mesoscutellum smooth and shining. Metascutellum smooth and shining with longitudinal carina.

Wing. Color varying from light to pale brown translucid to whitish translucid with iridescent shining. Forewing ML1 straight. RsL1 straight; as long as Rs+M. RSL2-3 slightly curved. ML2 short, about half-length of Rs+M. Rs+M and ML2 forming single slightly curved line, not forming angle with RsL2-3. Vein cu-a not reaching M+Cu ML1 angle by almost its half-length. Hindwing 1rs-m vein slightly curved. 7 to 10 hamuli.

Petiole. Node conical to campanulate; striae coarser than in workers.

Pilosity. Pubescence on mesosoma strongly curved, dense separated each other less than its length. Pubescence on mesoscutellum less dense. Pronotum with three to five pairs of short hairs, shorter than pronotum height.

Male

Non-type measurements: EL 0.68-0.74; HL 0.90-1.10; OW 0.15; OES 0.21-0.24; WL 2.80-3.10; FWL 5.40-5.80; PTH 0.90-1.00; PTL 0.60; PTW 0.40-0.50; GL 2.20-3.00; TL 6.3-7.2. PtI 1.50-1.66 (n= 6).

Head. Palp formula 4,3. Lateral ocelli partially surpassing posterior margin in frontal view; posterior margin between lateral ocelli straight to slightly concave, not reaching median ocellus.

Mesosoma. Pronotal dorsum with micro sculpture of reticulate aspect; with fine longitudinal striae effaced anteriorly and curved dorsally in lateral view. Propleuron with micro sculpture. Mesoscutum anteriorly with fine transverse striae, dorsal surface with longitudinal sulcus standing out, striae oblique diverging posteriorly towards parapsidial lines. Axilla and mesoscutellum with longitudinal striae, striae on central portion of mesoscutellum effaced. Mesoscutellum convex. Metascutellum with dense micro sculpture of reticulate aspect, with longitudinal carina. Mesopleuron with micro sculpture. Metapleuron and metepisternum rugulose with dense micro sculpture between them. Metapleuron and propodeum separated by longitudinal sulcus scrobiculate anteriorly to the spiracle. Propodeal dorsum with coarse irregular striae; dorsal and posterior face delimited by coarser irregular striae; posterior face with coarse rugae. Tarsal claw with pre-apical denticle.

Wing. Whitish translucid. Hamuli varying from 7 to 9, rarely 10. Pterostigma brown, contrasting to wing surface.

Petiole. Sessile; dorsal portion acute; coarsely imbricate on ventral portion gradually becoming smooth and shining dorsally. Subpetiolar process with apical portion blunt. Sternum concave posteriorly.

Color and size. Head, prothorax, mesothorax and legs and antenna pale yellow. Light brown spots on ocelli region and parapsidial lines. Propodeum dark brown. Petiole brown. Gaster light brown with posterior region yellowish. Relatively small (TL 6.30–7.20).

Pilosity. Head, mesosoma, petiole, and gaster with dense appressed pubescence. Pronotum with two thin erect hairs on posterior portion. Thin and erect short hairs on posterior portion of gaster segments I and II, hairs on segments III, IV, and V almost two times larger.

Natural history: Odontomachus bauri nests in the soil or under rocks and rotten trunks ( Oliveira & Hölldobler, 1989). There are records of nests in trunk cavities of living trees ( Jesus et al. 2012), and even in litter accumulated on old coconut leaf axilla ( Way & Bolton, 1997). Studying these nests on coconut trees, Way and Bolton (1997) observed frequent co-occurrence with colonies of Wasmannia auropunctata ( Roger, 1863) under O. bauri colonies or even between its galleries. The authors suggest that probably W. auropunctata prey on the eggs O. bauri .

The mandibular closing movement can reach 64m / s-1 ( Gronenberg, 1995). Such ability is used for hunting and to escape from predators when the ant bounces backward upon snapping its mandibles against the substrate ( Patek et al. 2006). Foraging ants make three to five pauses per minute and raise their head and based on laboratory experiments, Oliveira & Hölldober (1989) propose that the canopy pattern is an important visual clue to workers of O. bauri navigation when returning to their nest. Chemical communication is important for nestmate recognition and the chemical profile is different between colonies ( Morgan et al. 1999; Sainz-Borgo et al. 2011).

The venom of O. bauri has high proteolytic activity and in vitro also presents hemolytic and coagulant properties ( Silva et al. 2015). When tested in vivo the venom shows defibrinating properties. Furthermore, Silva et al. (2015) detected antibiotic effects against Staphylococcus aureus Rosenbach, 1884 . Escherichia coli (T. Escherich, 1885) and Toxoplasma gondii (Nicolle & Manceaux, 1908) . The sting of O. bauri causes local swelling, redness, and a burning sensation that might evolve into severe allergic reactions ( Rodríguez-Acosta et al. 2010; Rodriguez-Acosta & Reyes-Lugo, 2002). Seven pyrazines were found in mandibular gland extract ( Xu et al. 2018). There are records of endosymbiont bacteria living in the midgut of O. bauri ( Jesus et al. 2012; De Oliveira et al. 2016).

Odontomachus bauri can be collected with pitfall traps, Winkler’s extractor, and bait stations using tuna or sausage. Gynes and males can be collected at light- and Malaise-traps. Odontomachus bauri is frequently found in nests of Cornitermes cumulans (Kollar, 1832) ( Blattodea : Isoptera). It lives in forests, arid areas, pastures, and urban areas from the sea level to about 1,000 m height. It is found throughout the Neotropical region and the Caribbean, from Southern Brazil to the Dominican Republic and Haiti ( Fig. 58 ).

Comments: Odontomachus bauri is often confused with O. haematodus . Brown (1976) describes the typical form of the petiolar node as dome-shaped with convex anterior and posterior faces, with coarse striae extending to posterior face and the petiolar spine abruptly projecting. The only other species with this petiole configuration is O. erythrocephalus but, contrary to O. bauri , it has a reddish head. Some specimens have a conical node with an anterior face continuous with the spine and fine striae, similar to O. haematodus . The imbricate gastral sculpturing and dense gastral pubescence are also shared by both species. Brown (1976) mentions the metasternal process as a diagnostic feature, it is lip-shaped in O. bauri , whereas it forms a pair of spines in O. haematodus . Both characteristics are stable and diagnostic, despite differences in node shape and striation. Specimens from Northeast Brazil and Central America usually have a conical petiolar node, with attenuated striae. Brown (1976) also observed this variation in petiolar striae in populations from Central America and dry areas in Venezuela and Colombia, in small specimens with conical petiolar nodes from the same series as those with dome-shaped petiolar nodes with coarse striae. Like the workers, the gynes and males can also be recognized by their metasternal process.

Odontomachus cupreus sp. nov. and O. ruginodis may be confused for O. bauri , but they can be distinguished by the body color and propleuron sculpturing. Odontomachus bauri does not have a reddish-brown body with light brown appendages, and the propleuron does not have striae on the central portion. The petiolar striation seen in O. bauri lacks punctures that give to it a reticulate aspect. The striae on the posterior face of the petiolar node extend to the dorsal portion of the petiolar node. Both O. cupreus sp. nov. and O. ruginodis have a reddish-brown body, the propleuron with conspicuous striae on its central portion, and striae are punctate, or not surpassing the mid portion of the posterior face. Some older pinned specimens of O. bauri may become reddish, but the propleuron and the petiolar node striation are enough to recognize them.

Observing the syntype of O. haematodus paucidens some characteristics stand out: the external mandibular margins are more curved; the masticatory margin has acute denticles; the striae on the central disc of the pronotum are short and form concentric circles externally; the petiolar node striae are rugose and the dorsal portion of the node is quite narrow; and the gastral tergal is smooth and shining. Some specimens of O. bauri from South America have the pronotum striae forming concentric triangles, and due to this, the striate pattern of O. haematodus paucidens can be considered a variation. Brown (1976) mentions that is common for the teeth of Odontomachus to become worn with age, thus the syntype of O. haematodus paucidens could be a younger worker. Considering that Haiti is the type-locality of O. haematodus paucidens , it is important to examine more specimens of this variant, including series with gynes and males to ensure its synonymy under O. bauri . The character combination of O. haematodus paucidens was not observed in any continental specimens of O. bauri , thus the possibility exists that O. haematodus paucidens could be a Caribbean species. A single specimen from San Juan, Puerto Rico, (MZSP78392) matches all the characters of O. haematodus paucidens but it has the petiolar spine relatively longer than the type. The metasternal process, in the specimen from Puerto Rico, is bilobate with triangular and acute lobes. This unique metasternal process is similar to that observed in O. haematodus , however, the metasternal process in the latter does not form a pair of spines ( Fig. 26 ). As in O. bauri , none of the characteristics of O. haematodus paucidens were observed in any continental specimen of O. haematodus . Since the metasternum of the O. haematodus paucidens type-specimen could not be examined, the name remains as a synonym of O. bauri .

Material examined: 359☿, 33♀ and 23♂. BRAZIL : Acre: Mancio Lima (1☿) ; Senador Guiomard (1♀) . Alagoas: Maceió (1☿) . Amazonas: Itacoatiara (1☿) ; Manaus (1♀) ; Novo Airão (1♀) . Bahia: Contendas do Sincorá (1☿) ; Feira de Santana (1♂) ; Ilhéus (1♂) ; Itaberaba (1♂) ; Santa Rita de Cássia (2☿) . Ceará: Fortaleza (2☿) ; Crateús (4☿) ; Ubajara (1☿) . Distrito Federal: Brasília (11☿, 5♀) . Goiás: Formosa (3☿) ; Jataí (14☿, 4♂) ; Mineiros (3☿) . Maranhão: Carolina (2☿) ; Estreito (3☿) ; Imperatriz (1☿) ; São José do Ribamar (3☿) . Mato Grosso: Chapada dos Guimarães (3☿, 1♀) ; Corumbá (1☿) ; Dourados (5☿) ; São Félix do Araguaia (1☿) ; Tangará da Serra (3☿) ; Vila Bela da Santíssima Trindade (1☿) ; Sesc Pantanal (8☿, 1♀) . Mato Grosso do Sul: Aquidauana (1☿) ; Campo Grande (1☿) ; Dourados (2☿, 1♂) ; Paranaíba (4☿) ; Porto Murtinho (2☿) . Minas Gerais: Betim (14☿, 2♀) ; Boa Esperança (1☿) ; Buritizeiro (1☿) ; Cristália (5☿) ; Divinópolis (1☿, 3♀) ; Estrela do Sul (1☿) ; Manga (1☿, 4♂) ; Monte Camelo (1☿) ; Pandeiros (18☿, 2♀) ; Paracatu (10☿, 1♀) ; Rio Pardo de Minas (1☿, 2♀) ; Santana do Riacho (1♀) ; Uberlândia (1♂) ; Viçosa (4♂) . Pará: Alter do Chão (4☿) ; Belém (8☿) ; Benevides (4☿) ; Paragominas (3☿, 2♂) ; Parauapebas (5☿) . Paraíba: João Pessoa (1☿) ; [no further data] (1♀) . Paraná: Jaguariaiva (5☿) ; Morretes (1☿) ; Paranavaí (2☿) ; Pontal do Sul (1☿) . Piauí: Floriano (2☿) ; Itaueira (2☿) ; Parque Nacional Serra da Capivara (1☿) . Rio de Janeiro: Rio de Janeiro (9☿) . Rondônia: Cacoal (1☿) ; Ouro Preto do Oeste (4☿) ; Porto Velho (4☿) . Roraima: Ilha de Maracá (13☿) ; Ilha Marilé (1☿) . Santa Catarina: Itapema (4☿, 1♀, 1♂) . São Paulo: Bauru (1☿) ; Botucatu (1☿) ; Campinas (1☿) ; Cardoso (2☿) ; Jaci (1☿) ; Jales (1☿) ; Lins (2☿) ; Mirassol (2☿, 1♂) ; Monte Aprazível (1☿) ; Paraguaçu Paulista (1☿) ; São José do Rio Preto (1☿) . Tocantins: Araguacema (1♀) ; Pedro Afonso (3☿) . COLOMBIA: Santander: Capote (6☿) . COSTA RICA: Guanacaste: Zapotal (1☿) . Heredia: 11 Km ESE La Virgem (2☿) ; Estación Biológica La Selva (2☿) . Limón: Zent (3☿) . [no further data] (1☿) . DOMINICAN REPUBLIC: Barahona: La Ciénaga (1☿) . ECUADOR: Bolívar: Balzapamba (1☿) . Esmeraldas: 48 km S Atacames (37☿, 2♀) . Galapagos Islands: Santa Cruz Island (1☿) . Guayas: Manglaralto (4☿) ; Río Palenque (6☿) . Manabi: Punta Blanca (9☿) . Napo: Limoncocha (3☿) . FRENCH GUIANA: Saint-Laurent-du-Maroni: Saül: Bélvédére de Saül (4☿) . HAITI: Ouest: Paurt-ou- Prince (4☿, 2♀, 1♂) . MARTINIQUE: Ultramar: Saint-Pierre (6☿) ; [no further data] (2☿) . NICARAGUA: León: León (4☿) . PANAMA: Coclé: El Valle de Antón (1☿) . Panama: Panama. Pueblo Nuevo (1☿) . Panamá Oeste: Barro Colorado Island (6☿) . PERU: Cusco: Estación Biológica Villa Carmen (2☿) ; Madre de Dios: Puerto Maldonado (6☿) . Pasco: Villa Rica (1☿, 2♀) . Trujillo: Simbal (4☿) . TRINIDAD AND TOBAGO: Tunapuna – Piarco: Saint Augustine (2☿) . [ Without location] (1☿) . VENEZUELA: Bolivar: Mina los Pijiguaos (1♀) . Miranda: Sierra del Bachiller (1☿, 2♀) . Nueva Sparta. Margarita Island: 2k SSE San Sebastián (3☿) ; Asunción (1♂) ; Fuentidueño (1☿) ; San Sebastian (1☿) . Tachira: Pregonero (2☿) .

Figures

FIGURE 6. Variation of worker morphology of Odontomachus. In cephalic frontal view A, O. hastatus, mandibles elongated, vertex trapezoidal and long; B, O. chelifer mandibles short, vertex rectangular and short; C, O. bauri mandibles short and vertex trapezoidal. Pronotum in lateral view D, O. hastatus, triangular; E, O. biumbonatus angular; F, O. bauri, rounded. Petiole in lateral view G, O. hastatus, pedunculate and anteriorly elongated; H, O. chelifer sessile and angular; I, O. biumbonatus sessile and cylindrical; J, O. bauri sessile and conical. Gaster in lateral view K, O. hastatus, anterior and dorsal margins continuous forming a single convexity; L, O. chelifer and M, O. bauri, anterior margin straight forming blunt angle with dorsal convex margin. Dash lines and gray area representing shape of each structure. Scale bar = 1mm.

FIGURE 7. Variation of gyne morphology of Odontomachus. Pronotum and mesoscutum in lateral view (left) and dorsal view (right), forewing in dorsal view.A, O. hastatus, pronotum longer than high with dorsal margin straight, cervical area continuous to the pronotum, mesoscutum with short, almost vertical anterior margin that sharply curves onto horizontal dorsal margin; B, O. chelifer, pronotum dorsal margin straight, mesoscutum anteriorly convex curving onto dorsal margin; C, O. xeta sp. nov., pronotum dorsal margin slightly concave with angular aspect, mesoscutum broadly convex; D, O. bauri, pronotum dorsal margin convex, mesoscutum broadly convex. B, C and D pronotum in lateral view higher than long, in dorsal view constricted anteriorly forming neck. Dash lines representing shape of each structure. Scale bar = 1 mm. Wings out of scale.

FIGURE 15. Meso and metanotal striation of Odontomachus workers in dorsal view. A, mesonotum with longitudinal striae, mesometanotal sulcus vestigial (O. caelatus); B, mesonotum with transverse striae, mesometanotal sulcus scrobiculate (O. bauri). White squares with lines representing the striation pattern of mesonotum.

FIGURE 20. Pronotum of Odontomachus workers in lateral view. A, posterior portion of ventral margin of pronotum in lateral view with anteriorly curved long hairs, almost as long as the anterior procoxal hairs and propleuron with long erect hairs (O.laticeps); B, posterior portion of ventral margin of pronotum in lateral view without long hairs, propleuron with short decumbent hairs (O. bauri). Vertical arrows indicating the hairs on propleuron and horizontal arrows indicating the hairs on ventral portion of pronotum.

FIGURE 24. Body color pattern of Odontomachus workers in lateral view. A, head ferruginous, strongly contrasting with the dark brown body (O. erythrocephalus); B, head and body dark brown almost black (O. bauri).

FIGURE 26. Metaesternal process of Odontomachus workers in ventral view, middle coxae on superior portion and hind coxae on inferior portion. A, metasternal process forming pair of spines (O. haematodus); B, metaesternal process not forming pair of spines of (O. bauri). Dash lines highlighting the metasternal process shapes.

FIGURE 36. Petiolar nodes of Odontomachus gynes in lateral view. A, node smooth and shining (O. insularis); B, node with coarse striae (O. bauri).

FIGURE 37. Mesosoma of Odontomachus gynes in lateral view. A, mesopleuron with anteroventral portion forming an acute projection directed ventrally (O. chicomendesi sp. nov.); B, mesopleuron anteroventral portion not forming a blunt projection directed ventrally (O. bauri). Dash lines highlighting the mesopleuron shape.

FIGURE 46. Metasternal process of Odontomachus males in ventral view.A, forming a pair of spines (O. haematodus); B, with pair of lateral cuticle borders (O. bauri). Dash lines highlighting the metasternal process shapes.

FIGURE 47. Mesoscutum color pattern of Odontomachus males. A, with dark-brown spots (O. bauri); B, without dark-brown spots (O. ruginodis, CASENT0104177, imaged by: April Nobile, Source: AntWeb.org.

FIGURE 51. Map of distribution of O. affinis, O. allolabis and O. panamensis. Triangles representing the type-localities.

FIGURE 53. Odontomachus allolabis holotype.A, head in frontal view; B, full dorsal view; C, full lateral view.Arrow pointing to the ventral gaster opening. Source: MZSP, imaged by: Mônica Ulysséa.

FIGURE 55. Odontomachus bauri worker. A, head in frontal view; B, full lateral view; C, metasternum in ventral view with middle coxae at superior portion and hind coxae at inferior portion; D, mesosoma in dorsal view; E, petiole in lateral view; F, gaster in dorsal view.

FIGURE 56. Odontomachus bauri gyne. A, head in frontal view; B, mesosoma in dorsal view; C, full lateral view.

FIGURE 57. Odontomachus bauri male.A, head in frontal view; B, mesosoma in dorsal view; C, propodeum in posterior view; D, full lateral view.

FIGURE 58. Map of distribution of O. erythrocephalus and O. bauri. Triangles representing the type-localities.