Odontomachus xeta, França & Fernandes & Bravo, 2024

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 : 131-145

Odontomachus opaciventris Forel, 1899 ( Figures 64 and 105 )

Odontomachus haematodus r. opaciventris Forel, 1899: 21 (☿ and ♀); status as species by Kempf, 1972: 172.

Type specimens: Syntypes [Images]. COLOMBIE [ COLOMBIA]: Don Diego (Forel), USNM ENT00531648 2☿ [ NMNH]/ Same data, GBIF-D/FoCol 0687 1☿ [ SMNK]. COLOMBIE [ COLOMBIA]: St[San]Antonio ( Forel [col.]), Coll. Forel, ANTWEB CASENT0907435 1☿ [ MHNG]. [ PANAMA]: [Chiriqui], Bugaba, [Volcan de Chiriqui], ( Champion [col.]), 800- 1.500 ft., ANTWEB CASENT0900586 1☿ [ MHNUK] .

Etymology: Combination of the Latin words opacus = shady, dark, obscure + venter = belly; probably referring to the gaster color and sculpturing, which is punctate, given to it a dark and opaque aspect.

Diagnosis: (☿) Propleuron with concentric striae with central portion effaced.Mesonotum with regular transverse striae. Petiolar node cylindrical with fine irregular transverse to oblique striae. Gastral terga densely punctate. (♀) Propleuron, petiolar node and gastral terga as in worker. (♂) Unknown.

Worker

Syntype measurements: EL 0.38-0.42, HL 2.94-3.23, HoW 2.30-2.61, HvW 2.09-2.23, ML 1.64-1.71, SL 2.53-2.81, PnW 1.25-1.37, WL 3.24-3.62, FL 2.73-3.32, PTH 1.12-1.26, PTL 0.58-0.60, PtW 0.44-0.52, GL 2.58-3.66, TL 11.05-12.75. CI 0.68-0.71, MI 0.50-0.58, PtI 1.93-2.17, SI 0.86-0.87, VI 0.89-0.93.

Non-type measurements: EL 0.4-0.5, HL 3.4-3.6, HoW 2.6-2.9, HvW 2.2-2.3, ML 2.0-2.2, SL 2.9-3.8, PnW 1.5-1.7, WL 4.0-4.2, FL 3.5-3.7, PTH 1.5-1.7, PTL 0.6-0.7, PtW 0.5-0.6, GL 3.4-4.2, TL 13.4-14.9. CI 0.67-0.72, MI 0.58-0.61, PtI 2.14-2.50, SI 0.85-1,08, VI 0.85-0.95 (n= 3).

Head. Vertex trapezoidal wider than long in frontal view; with regular longitudinal striae diverging posteriorly. 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 acute. Clypeus with fine irregular longitudinal striae on median portion. Malar area wrinkly-punctate on anterior portion in latero-oblique view, posterior portion with inconspicuous transverse striae.

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

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

Mesosoma. Pronotum in lateral view dorsal margin rounded to slightly angulated; neck well developed anteriorly in dorsal view; lateral margin rounded, posteriorly forming slightly obtuse angle; central disc of pronotum with regular longitudinal striae forming gradually two concentric longitudinal ellipses converging anteriorly, striae irregular posteriorly; lateral striae forming concentric circles. Propleuron with fine transverse striae gradually forming concentric arcs on central portion slightly effaced. Mesonotum wider than long, slightly concave medially; with regular transverse striae. Mesopleuron with rounded carina on anteroventral portion; mostly smooth and shining, anterior portion with regular transverse striae curved dorsal-anteriorly. Notopropodeal sulcus scrobiculate. Metanotum as long as notopropodeal sulcus; with irregular transverse striae. Metapleural gland bulla with effaced transverse striae anteriorly. Propodeum in lateral view straight, slightly concave on posterior portion; posterior margin length about 1/3 of dorsal length. Metasternum with metasternal process close, cuticle border forming arc; inconspicuous puncture anteriorly, regular transverse striae posteriorly.

Petiole. Sessile. Cylindrical node, ventral portion slightly wider than dorsal portion in lateral view; posterior margin convex on dorsal portion, medially forming two blunt lateral projections in lateral-oblique view. Spine robust, long and straight or curved posteriorly, as long as node half-length. Regular and fine transverse punctate striae on lateral face effacing dorsally. Subpetiolar process almost long than wide, keel-shaped; tip blunt; posterior portion concave.

Gaster. First tergum almost higher than long; anterior and dorsal margin meeting in a slightly convex surface not forming an angle; dorsal face convex; dorsal face of all terga strongly punctate.

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

Pilosity. Long and dense pubescence on head and gaster longer than scape length, separated each other less than 1/3 of its length. Pubescence on mandible, mesosoma and petiole shorter and sparser than head pubescence. Pubescence on petiole limited to anterior face extending to lateral faces. Short hairs on anterior portion of procoxa and propleuron, smaller than coxae width. Pronotum with three or four pairs of long, curved erect hairs longer than maximum procoxa width. Long erect hairs on posterior 2/3 of gastral terga directed posteriorly, as long as pronotum hairs.

Natural history: Workers forage individually on the soil or the leaf litter, usually at dusk or dawn. Colonies are monogynous and can reach up to 10,000 adults along with 2,000 larvae and cocoons. The nests are built in rotten tree trunks or in the soil beneath them (Lachaud in De la Mora et al. 2008). In Chiapas, Mexico, it occurs in cocoa and coffee plantations ( Lachaud & García-Ballinas, 2001).

In artificial conditions, De la Mora et al. (2008) described its hunting behavior, which is usual for the genus. However, in contrasting to the other Odontomachus species, O. opaciventris do not display antennal palpation of the prey, at most touch it quickly, and start skirting around avoiding any contact before the mandible striking. After capture, the worker stings the prey in the intersegmental membrane until it stops moving. In some cases, the mandible strike can bounce the prey away and the worker usually starts to rapidly search for it in a spiral-shaped trajectory. When handling termites in the experiments, workers did not sting them ( De la Mora et al. 2008). Odontomachus opaciventris is distributed from northeastern South America to Central America ( Fig. 65 ).

Comments: According to Forel (1899), in the original description, O. opaciventris is similar but larger and more robust than O. laticeps . In the original illustration ( Tab.1. Figs. 14 and 14a from Forel, 1899), it is possible to recognize the cylindrical petiolar node with the ventral portion slightly wider than the dorsal portion, as in O. biumbonatus and O. xeta sp. nov. Odontomachus meinerti can be confused for O. opaciventris due to similarity on the gastral terga sculpturing. However, O. opaciventris is larger and darker than O. meinerti , its node shape is cylindrical with an acute spine and it has concentric striae on the propleuron with an effaced central portion. The shape of the petiolar node of O. meinerti can be described as an isosceles triangle bearing a short and robust spine. The gastral terga of O. opaciventris is always densely punctuate while in O. meinerti is usually punctate-striate. Densely punctate gastral terga can also be found in O. scalptus , but O. opaciventris has transverse striae on the mesonotum and a cylindrical petiolar node while O. scalptus has longitudinal striae and a conical petiolar node.

Specimens from South America have the vertex narrower and the petiolar striae less coarse than those from Central America. The specimens from Central America present the propleural striation varying from entirely striated to effaced in the central portion, while the South America specimens have it completely striate.

One atypical specimen identified as O. opaciventris , collected in the Reserva Ducke in Amazonas state, Brazil, was found in the INPA collection. The vertex shape of this specimen is trapezoidal, and the gastral terga are completely punctate, as usual for the species, but the petiolar node is conical, instead of cylindrical like in O. opaciventris , and its anterior portion is slightly convex. All of these characters combined suggest that it might be O. scalptus . However, the mesonotum striation, which is longitudinal in O. scalpus , in this specimen is transverse, like in O. opaciventris . This could be an aberrant O. scalptus , but all examined specimens of O. scalptus and O. opaciventris have stable metanotal striae, and due to the lack of more specimens we decided to not describe it as a new species.

Material examined: 6☿, 1♀. COSTA RICA: Ajuela: Florencia , 10km N (3☿. 1♀); [Limón]: R[Río] Toro Amarillo, vic[vicinity] Guápiles (1☿) . HONDURAS: Olancho: 9km N Catacamas (1☿) . PANAMA: Darién: Reserva Chucantí (1☿) .

Odontomachus panamensis Forel, 1899 ( Figures 13-B , 14-B , 29-B , 51 , 106 and 107 )

Odontomachus panamensis Forel, 1899: 19 (☿, ♀ and ♂); subspecies of Odontomachus affinis by Emery, 1911: 113; status as species by Kempf, 1972: 7, 172.

Odontomachus affinis mayi Mann, 1912: 39 (☿); status as species by Kempf, 1972: 7, 172; new synonym.

Type specimens: Syntypes [Images]. Odontomachus affinis panamensis Forel, 1899 ; PANAMA: Bugaba [Bugabá], [Volcan de Chiriqui], 800- 1.500 ft., Champion [col.], TYPE No.A.M.N.H., M.C. Z. co Type 20520 1☿ [ MCZ]/ Same data, 99-304, BMNH (E) 1013997, ANTWEB CASENT0900584 1☿ / Coll. Forel 1☿ [ MHNG] .

Syntypes [Images]. Odontomachus affinis mayi Mann, 1912 ; BRAZIL: Rio [River] Madeira, [Madeira Mamoré Railroad Company, 306 km from San Antonio, Matto Grosso, now Rondônia], W. M. Mann collector, Camp #41, BMNH (E) 1013980, ANTWEB CASENT0900585 1☿ [ BMNH]/ BRAZIL [BRASIL]: Rio Madeira , Manu & Baker [col.?], USNM ENT 00531540 1☿ [ NMNH]/ Same data, 112, COTYPE No. A.M.N.H., M.C. Z. co Type 4-6 20519 1☿ [ MCZ] .

Etymology: It refers to the type locality of this species at Panamá.

Diagnosis: (☿) Vertex smooth and shining. Central disc of pronotum striae forming concentric triangles or acute angles anteriorly. Mesopleuron with anteroventral rounded lobes directed laterally. (♀) Vertex and mesopleuron as in worker. In lateral view, pronotum striae usually irregular. Body color yellow to orangish. (♂) Not examined.

Worker

Syntypes measurements: EL 0.27-0.27, HL 1.65-1.76, HoW 1.29-1.37, HvW 0.86-0.92, HW 1.05-1.12, ML 0.98- 1.01, SL 1.53-1.57, PnW 0.68-0.69, WL 2.18-2.20, FL 1.84, PTH 0.72-0.75, PTL 0.44-0.45, PtW 0.28, GL 1.40,1.37, TL 6.65-6.79. CI 0.63, MI 0.57-0.59, PtI 1.60-1.70, PtI 1.60-1.70, SI 0.89-0.92, 0.81-0.82.

Non-type measurements: EL 0.4-0.5, HL 2.0-2.7, HoW 1.6-2.1, HvW 1.1-1.5, HW 1.3-1.7, ML 1.3-1.6, SL 2.1-2.6, PnW 0.9-1.1, WL 2.8-3.6, FL 2.3-3.1, PTH 1.0-1.3, PTL 0.5-0.6, PTW 0.4-0.4, GL 2.5-3.7, TL 9.1-11.5. CI 0.59-0.80, MI 0.55-0.8, PtI 1.83-2.20, SI 0.92-1.15, VI 0.84-0.93 (n= 15).

Head. Vertex trapezoidal, wider than long in frontal view; almost smooth and shining, with effaced striae limited to anterior portion. Posterior margin concave medially; 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 on median portion. Malar area smooth and shining in latero-oblique view.

Mandible. Almost as long as anterior head portion. External margin slightly convex. Masticatory margin with denticles that serially increase in size apically. Palp formula 4.3.

Antenna. Scape surpassing occipital corner by 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 with regular striae forming concentric triangles; lateral striae gradually forming concentric circles. Propleuron smooth and shining. Mesonotum wider than longer; with regular transverse striae slightly curved anteriorly. Mesopleuron with anteroventral portion with rounded projection directed laterally; mostly smooth and shining, anterior portion with irregular transverse striae. Mesometanotal sulcus well-marked, scrobiculate. Metanotum as long as notopropodeal sulcus; with irregular transverse striae. Metapleural gland bulla with inconspicuous transverse striae on dorsal portion. Propodeum in lateral view straight; posterior margin length about 1/3 of dorsal length. Metasternum with metasternal process close forming thin arc by cuticle border, sometimes with median notch; regular fine transverse striae.

Petiole. Sessile. Conical node, anterior margin in lateral view slightly convex to straight. Spine acute, straight or slightly curved posteriorly. Smooth and shining to imbricate. 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. In dorsal view, gastral terga smooth and shining.

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

Pilosity. Scattered, conspicuous and short pubescence spread over the body, separated each other more than its length. Pubescence on petiole limited to anterior face extending to lateral faces. Pubescence on gaster dense, separated each other by less than its half-length. Long hairs on anterior portion of procoxa as long as coxae width. Pronotum with three or four pairs of long, curved erect hairs longer than maximum procoxa width. Long erect hairs on gastral terga directed posteriorly, as long as pronotum hairs.

Gyne

Non-type measurements: EL 0.5, HL 2.1-2.8, HoW 2.1-2.4, HvW 1.6-1.8, HW 1.8-2.0, ML 1.6-1.8, SL 2.5-2.7, PnW 1.2-1.5, WL 3.7-4.3, FL 2.9-3.1, FWL 6.6-7.3, PTH 1.1-1.6, PTL 0.6-0.8, PtW 0.6-0.7, GL 3.1-4.1, TL 11.7- 12.8. CI 0.64-0.85, MI 0.57-0.76, PtI 1.57-2.5, SI 0.89-1.19, 0.88-0.90 (n= 8).

Mesosoma. Pronotum longer than high in lateral view, dorsal margin straight; lateral margins converging anteriorly forming a neck in dorsal view; with irregular transverse striae forming arcs directed posteriorly on lateral face. Subalar area separated from pronotum by transverse impression; with microsculpture. Mesoscutum anterior and dorsal margin forming single convexity in lateral view; with regular longitudinal striae in dorsal view, some striae might be coarser standing out; 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 sometimes with inconspicuous microsculpture anteriorly. Mesoscutellum smooth and shining with inconspicuous puncture, with vestigial longitudinal carina. Metascutellum sculpture as like mesoscutellum.

Wing. Color pale yellow, translucid. ML1 slightly curved. RsL1 straight; as long as Rs+M. RSL2-3 curved. Rs+M and ML2 forming single curved line, not forming angle with RsL2-3; Rs+M slightly longer than ML2. Forewing 1rs-m vein slightly curved. 7 to 9 hamuli.

Petiole. Conical node, anterior face straight to slightly concave, posterior face convex on dorsal portion.

Pilosity.Pubescence on mesosoma strongly curved, dense separated each other less than its length.Mesoscutellum with long erect pubescence longer than mesoscutum pubescence. Pronotum with three or four pairs of short hairs, length less than procoxa width.

Natural history: Odontomachus panamensis is an arboreal and nocturnal species that nests in epiphytes or ant gardens ( Corbara & Dejan, 1998; Gibernau et al. 2007). The colonies can reach over 2,000 individuals and can be polycalic ( Orivel et al. 1998). Orivel et al. (1988) observed, in the laboratory, that workers transport seeds of Aechmea mertensii (G. Mey.) Schult. & Schult.f. ( Bromeliaceae ) and Anthurium gracile (Rudge) Lindl. ( Araceae ) to their nests and incorporate them into the walls, suggesting that O. panamensis creates ant gardens. The authors also observed a high frequency of aggressive behaviors displayed between workers from different colonies. However, the workers were tolerant to individuals of other species that lived in the same ant garden. The arboreal and nocturnal habitus might explain the less frequent records, and hence the patchy distribution ranging from the Brazilian Amazon to Central America ( Fig. 51 ).

Nests of Paratrigona pannosa ( Apidae : Meliponini ) were found associated with nests of O. panamensis in French Guiana ( Corbara & Dejan, 1998). Mann (1912) observed an association with Dolichoderus debilis Emery, 1980 .

Comments: Amongst the species with vertex and gastral terga smooth and shining (ie., O. affinis , O. allolabis and O. hastatus ), O. panamensis can be distinguished for being the only species with rounded projections on the anteroventral portion of mesopleuron (see comments).

The pronotum striae of O. panamensis usually form concentric triangles on the central portion but, in some cases, they can be longitudinal forming acute angles anteriorly. The mesopleuron projections also vary in size, and the anterior face of the petiolar node can be straight or slightly convex on the dorsal portion, giving it a campanulate aspect. Some specimens from French Guiana have it slightly concave.

Originally, both O. panamensis and O. mayi were described as subspecies of O. affinis and considered as valid species by ( Kempf, 1972). The mesopleural projections of O. mayi would be enough to distinguish it from O. panamensis , which lacks them ( Kempf, 1972; Brown. 1976). The type-specimen of O. panamensis (CASENT0900584) does not have well-developed mesopleural projections, but 205 workers from a nest collected in Amazonas state, Brazil, were examined and some individuals had and others did not have well-developed mesopleuron projections. Specimens from Central America also have well-developed mesopleuron projections. In the phylogeny of Odontomachus ( Fernandes et al. 2021) , the terminals representing O. mayi and O. cf. panamensis are recovered as monophyletic ( Fig. 1 ). Furthermore, the biology of both species is similar as they nest in epiphytes. Considering the morphological, phylogenetic and biological evidence, O. mayi is synonymized here under O. panamensis .

Odontomachus panamensis is placed as a sister species of O. scalptus , but without good support ( Fernandes et al. 2021). Both species are very contrasting in their morphology and biology. Taking in to account the morphological similarity of O. panamensis with O. insularis , they probably are closely related due to their yellowish body color and the petiolar node smooth and shining to weakly striate on the ventral portion with slender spine.

Material examined: 260☿, 8♀. BRAZIL: Amapá: Rio Duvidoso (1☿) . Serra do Navio (1☿) . Amazonas: Benjamin Constant (14☿) ; BR 174, Km 45 (8☿) ; Manaus , RFAD [Reserva Florestal Adolpho Ducke] (205☿) . Ceará: Itapipoca (3☿) . Mato Grosso: Sinop (1♀) . Pará: Belém (20☿) . Rondônia: Jamari (1♀) ; Ji-Paraná (1♀) . COSTA RICA: Heredia: La Selva Biological Station, 3km S Pto. [Puerto] Viejo (2☿, 1♀) . FRENCH GUIANA: [Cayenne:] Camopi, Oyapock (1♀) ; Roura, Montagne dès Chevaux (1☿, 2♀) . VENEZUELA: [no further data], Alto Río Siapa (2☿) .

Odontomachus ruginodis Wheeler, 1908 ( Figures 27-B , 47-B , 78 , 108 , 109 and 110 )

Odontomachus haematoda insularis var. ruginodis Wheeler, 1905: 82 (☿ and ♀), unavailable infrasubspecific name. Odontomachus haematodes var. ruginodis Wheeler, 1908: 126 (☿); status as species by Wilson, 1964: 4; junior synonym of

Odontomachus brunneus by Brown, 1976: 103; Deyrup et al. 1985: 192 (♂) and status as species.

Type specimens: Syntype [Images]. Odontomachus haematoda insularis var. ruginodis Wheeler, 1905 . BAHAMAS: [New Providence Island] Nassau , [Queen’s Staircase and Fort Charlotte], May-June 1904, W. M. Wheeler col., COTYPE No. A. M. N. H., USNM ENT 00531979 3☿, 1♀ [ NMNH]/ Same data, M.C. Z. coType 4-7 9880, 1☿ [ MCZ] .

Etymology: Combination of the Latin words ruga = wrinkle, crease + nodus = knot, swelling; probably referring to the petiolar node sculpturing which is irregularly and finely striate.

Diagnosis: (☿ and ♀) Body tricolored, red orangish, mesosoma and petiole reddish brown and gaster dark-brown almost black. Propleuron smooth and shining to coarsely imbricate with fine oblique striae restricted to anterior portion. Petiolar node conical; with irregular transverse striae extending to posterior face and coarser on ventral portion; petiolar spine standing out from petiolar node, short acute and slightly curved posteriorly. Gastral terga smooth and shining. (♂) Not examined, (see Deyrup et al, 1985; Macgown et al. 2014).

Worker

Non-type measurements: EL 0.3-0.4, HL 1.9-2.2, HoW 1.5-2.0, HvW 1.2-1.3, HW 1.3-1.5, ML 1.0-1.2, SL 1.6-1.8, PnW 0.8-1.0, WL 2.3-2.7, FL 1.7-1.9, PTH 0.9-1.0, PTL 0.4, PTW 0.3-0.4, GL 2.0-3.6, TL 7.6-9.9. CI 0.68-0.71, MI 0.5-0.57, PtI 2.25-2.50, SI 0.81-0.85, VI 0.85-0.92 (n= 7).

Head. Vertex trapezoidal, wider than long in frontal view; with regular longitudinal striae diverging posteriorly. 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 longitudinal striae on median portion. Malar area smooth and shining in latero-oblique view.

Mandible. Almost as long as anterior head portion. External margin convex. Masticatory margin with 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 margin convex; neck well developed anteriorly in dorsal view; lateral margin rounded; central disc of pronotum with regular longitudinal striae, lateral striae forming concentric acute arcs directed anteriorly to circles. Propleuron smooth and shining; regular transverse striae limited to anterior portion. Mesonotum larger than wide; with regular transverse striae. Mesopleuron with rounded carina on anteroventral portion; mostly smooth and shining, anterior portion with regular transverse striae curved dorsal-anteriorly. Mesometanotal sulcus well-marked, scrobiculate. Metanotum as long as notopropodeal sulcus; with irregular fine transverse or longitudinal striae extending to anterior propodeum portion. Metapleural gland bulla with fine transverse striae. Propodeum in lateral view straight; posterior margin length about 1/3 of dorsal length. Metasternum with metasternal process close, posterior cuticle border bilobate; regular transverse striae.

Petiole. Sessile. Conical node, anterior margin in lateral view convex dorsally, not continuous with petiolar spine. Spine short, acute, curved posteriorly. Irregular transverse striae extending to posterior margin, 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 smooth and shining with inconspicuous imbrications.

Color and size. Body light brown to reddish brown. Gaster dark brown. Legs and antennae yellowish. Relatively small size.

Pilosity. Hook-shaped, dense, conspicuous and short pubescence spread over the body, separated each other about its half-length. Short hairs on anterior portion of procoxa smaller than coxae width. Pronotum with two or three pairs of curved erect hairs almost long than maximum procoxa width. Short subdecumbent sparse hairs on posterior 3/4 of gastral terga directed posteriorly. Shorter than procoxa hairs.

Gyne

Non-type measurements: EL 0.4, HL 2.1, HoW 1.7, HvW 1.3-1.4, HW 1.5-1.6, ML 1.1, SL 1.7, PnW 1.1-1.2, WL 2.7-2.8, FL 1.9, FWL without wings, PTH 1.1, PTL 0.5, PTW 0.5, GL 2.6-3.1, TL 8.5-9.1. CI 0.71-0.76, MI 1.0- 0.52, PtI 2.2, SI 0.80, VI 0.86-0.87 (n= 2).

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 on lateral face not forming arcs. 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 vestigial longitudinal carina.

Wing. Pterostigma dark brown, contrasting with wing surface. Hindwing 1rs-m vein straight. 8 hamuli.

Petiole. Conical to campanulate node; striae coarser than 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.

Natural history: Odontomachus ruginodis nests under stones and in the soil at the base of oaks and bushes, the colonies are relatively small with about a dozen workers and it is predominantly nocturnal ( Wheeler, 1905; Macgown et al. 2014). They can be found in open and sunny areas with sandy soil ( Wheeler, 1908), and also in areas with at least a small amount of leaf litter ( Macgown et al. 2014). Apparently, the Nearctic population has the males’ flight correlated to the moonlight ( Deyrup et al. 1985). Five pyrazines were detected in mandibular gland extractions ( Xu et al. 2018).

Odontomachus ruginodis is native to the Caribbean islands and is also widely distributed in Central America and the southeastern United States of America ( Fig. 79 ). It can be found as an invasive species in the Galapagos Islands, nesting under rocks in open disturbed areas and at beaches ( Herrera et al. 2014; Herrera et al. 2023). Odontomachus ruginodis is recorded in Brazil in the Fernando de Noronha Islands ( Rafael et al. 2020), confirming the absence of the species in the continental part of South America ( Fig. 79 ).

Comments: Odontomachus ruginodis is a relatively small and reddish-brown species with gaster dark brown that can be confused with O. brunneus or O. bauri . In the first case, O. ruginodis can be distinguished by the striate-punctate petiolar node with a slender spine. Odontomachus brunneus has a smooth and shining node with at most some fine striae limited to its ventral portion and a reduced spine. Odontomachus ruginodis can be distinguished from O. bauri by the red body color and the petiolar node striation punctate, while O. bauri is black to dark brown and the petiolar node striation is not punctate (see O. bauri comments for old pinned specimens).

The epithet ruginodis was first published by Wheeler (1905) as Odontomachus haematoda insularis var. ruginodis , but is considered unavailable (Bolton, 2023). In a subsequent publication, Wheeler (1908) describes the name as a subspecies and mentions worker and gyne of O. haematoda ruginodis from Utuado, Porto Rico. According to Bolton (2024), the type-locality of O. ruginodis is Bahamas, New Province Island, the locality of the types of O. haematoda insularis ruginodis . Considering that the name was published as valid in 1908, the type locality of O. ruginodis is Utuado, Porto Rico. As it was not possible to visit the MCZ and NMNH collections to search for the series from Puerto Rico, we keep the status of the studied type-specimens as only the series of O. haematoda insularis var. ruginodis , since they correspond to the morphology of this species.

In the phylogeny, O. ruginodis was recovered in a clade of two sister lineages, both with high support ( Fig. 1 ), and distinct distributions. One lineage corresponds to specimens from Central America and the other to specimens from South America, respectively corresponding to O. ruginodis and O. cupreus (= O. cf. ruginodis in Fig. 1 ). Both species are very similar in body color, petiole shape, and sculpturing. The only difference is that O. cupreus has the propleuron with conspicuous striae and usually the posterior portion of the procoxa is covered with fine longitudinal striae. The geographic isolation of both populations ( Fig. 78 ) and the high phylogenetic support corroborate the hypothesis of O. cupreus as a distinct species.

Material examined: 28☿, 4♀. BRAZIL: Pernambuco: Fernando de Noronha (4☿, 3♀) . COSTA RICA: Heredia: [ Sarapiqui ] (4☿) . CUBA: [Ciudad de La Havana]: Havana (4☿) . JAMAICA: [Saint Ann]: Ocho Ríos (1☿) . MEXICO: Jalisco: Casimiro (2☿) . Veracruz: 1 mile north from Minatitlan (3☿) ; Palma Sola (1♀) . PANAMA: Los Santos: Pocrí (2☿) . [Panamá Oeste]: Barro Colorado Island (3☿) . SAINT KITTS AND NEVIS: Nevis Island :

[no further data] (1☿). TRINIDAD AND TOBAGO: [no further data] San Vicent (2☿) . UNITED STATES: Florida: Sarasota Co. [County] (2☿) .

Odontomachus scalptus Brown, 1978 ( Figures 16-B , 17-A , 31-A , 33-A , 34-B , 71 , 111 and 112 )

Odontomachus scalptus Brown, 1978: 281 (☿).

Type specimens: Holotype [Image]. EQUADOR [ ECUADOR]: Prov.[ Province ] Napo, 20 km S of Tena, 600m, S. & J. Peck [cols.], 11 Jul [11.vii.], B3 60, 34796, MCZ ENT 00034796 1☿ [ MCZ].

Etymology: From the Latin word scalpo = to carve, to scratch, to draw nails across; probably referring to the mesonotum or gastral terga sculpturing which are striate.

Diagnosis: (☿) Mesonotum with longitudinal striae straight not forming arcs anteriorly in lateral view. Gastral terga entirely punctate or anteriorly punctate becoming longitudinal striated posteriorly. (♀) gastral terga as in worker. Pronotum with transverse striae strongly curved anteriorly forming an acute angle. (♂) Unknown.

Worker

Holotype measurement. EL 0.25, HL 1.71, HoW 1.36, HvW 1.02, HW 1.19, ML 0.96, SL 1.68, PnW 0.73, WL 2.11, FL 1.36, PTH 0.75, PTL 0.39, PTW 0.29, GL 1.66, TL 6.83. CI 0.69, MI 0.56, PtI 1.92, SI 0.98, VI 0.85.

Non-type measurements: EL 0.40-0.50, HL 2.10-3.00, HoW 1.80-2.80, HvW 1.00-1.90, HW 1.20-2.10, ML 1.40-1.70, SL 2.20-2.80, PnW 0.90-1.30, WL 2.80-3.50, FL 2.40-3.10, PTH 1.00-1.40, PTL 0.50-0.60, PTW 0.40- 0.50, GL 2.10-3.70, TL 9.3-12.2. CI 0.57-0.72, MI 0.53-0.60, PtI 1.83-2.80, SI 0.84-1.16, VI 0.81-1.20 (n= 30).

Head. Vertex rectangular wider than long in frontal view; with regular longitudinal striae. 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 fine longitudinal irregular striae on median portion. Malar area with fine irregular transverse striae in latero-oblique view.

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

Antenna. Scape surpassing occipital corner by pedicel length.

Mesosoma. Pronotum in lateral view rounded, dorsal margin slightly convex; neck well developed anteriorly in dorsal view; lateral margin slightly forming obtuse angle posteriorly; central disc of pronotum with longitudinal striae, lateral striae forming concentric arcs directed anteriorly. Propleuron with fine transverse striae gradually forming concentric arcs on central portion slightly effaced. Mesonotum wider than long; with irregular longitudinal striae. Mesopleuron with rounded carina on anteroventral portion; with fine regular transverse striae on all surface, effaced on central portion. Mesometanotal sulcus vestigial, metanotum continuous with mesonotum; striate as mesonotum but slightly scrobiculate. Metapleural gland bulla smooth and shining, at most with inconspicuous fine transverse striae anteriorly. Propodeum in lateral view irregular with two shallow impressions; posterior margin length about 1/3 of dorsal length. Metasternum with metasternal process open, cuticle border bilobate separated on middle line by longitudinal sulcus; regular transverse striae, tegument between striae punctate; metasternal process open, cuticle border bilobate separated on middle line by longitudinal sulcus.

Petiole. Sessile. Conical node, anterior margin in lateral view convex; posterior margin usually more convex than anterior face. Spine robust, long, straight to slightly curved posteriorly. Irregular, fine, transverse striae on all surface except by dorsal portion of posterior margin. 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 first, second and third terga densely punctate gradually becoming longitudinally striated posteriorly, or completely punctate; fourth terga punctate.

Color and size. Body brown to nut-brown, gaster darker. Legs and antennae brown to light brown. Articulations usually yellowish. Relatively medium to large size ants.

Pilosity. Short, dense pubescence spread all over the body separated each other about its length. Short hairs on anterior portion of procoxa smaller than coxae width. Pronotum with three or four pairs of hairs little longer than procoxa hairs. Subdecumbent hairs on posterior 3/4 of gastral terga directed posteriorly, as long as pronotum hairs. Gyne

Non-type measurements: EL 0.5, HL 2.9, HoW 2.4, HvW 1.9, HW 2.1, ML 1.7, SL 2.7, PnW 1.5, WL 4.0, FL 2.9, FWL without wings, PTH 1.6, PTL 0.7, PtW 0.7, GL 4.0, TL 13.3. CI 0.72, MI 0.58, PtI 2.28, SI 0.93, VI 0.94 (n= 1).

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

Petiole. Conical node, anterior face straight, posterior face slightly convex on dorsal portion. Striae coarser than worker petiole.

Pilosity. Pubescence on mesosoma strongly curved, dense separated each other by less than its length. Subalar area with short whitish appressed pubescence. Pubescence on mesoscutellum less dense. Pronotum with five pairs of long hairs, as long as procoxa width.

Natural history: Odontomachus scalptus nests in the soil and its karyotype is 2n= 44, 2SM+16ST+26T ( Mariano et al. 2011). It can be collected with pitfall traps and in the leaf litter. Odontomachus scalptus can be collected with Winkler’s extractors or Berlese funnels. Specimens are usually found inhabiting forest areas and are widely distributed in Amazonian forests, occurring from about 100 m to 800 m altitude ( Fig. 72 ).

Comments: Among the Amazonian species that occur in the Amazon Forest and have longitudinal striae on the mesonotum, O. scalptus is often confused with O. caelatus since the gastral terga of both are densely sculptured. Odontomachus scalptus can be quickly recognized by the almost straight mesonotal striation on the lateral portions and due to the gastral terga being usually punctate, gradually becoming longitudinally striated posteriorly; whereas O. caelatus has arched striae on the lateral portions of mesonotum and the gastral terga longitudinally striate without any punctures. In some cases, the gastral terga of O. scalptus are entirely punctate. On the other hand, O. caelatus has longitudinal striae on the gastral terga, sometimes diverging posteriorly, but never presents punctations.

Using the identification key provided by Brown (1976), O. scalptus would be identified as O. yucatecus , as in this key he does not mention the smooth and shining gastral terga of O. yucatecus ). Even Brown (1978) called attention to this issue, several specimens of O. scalptus were found misidentified as O. yucatecus . In both species, the striation on the lateral portions of the mesonotum is almost straight, but the sculpturing of the gastral terga are enough to distinguish them: in O. yucatecus is imbricate to smooth and shining, and in O. scalpus is usually punctate.

Odontomachus scalptus have some markable variations but even so, they fit in the morphological boundaries of this species. The striae on the propleuron can be conspicuous on all the surface, but some specimens have the central portion effaced. The convexity of the anterior face of the petiole and the curvature of the petiolar spine are very variable, and in some specimens, the gastral terga instead of being only punctate, it can also have very short and inconspicuous longitudinal striae on its posterior margin. These variations can be observed in the populations examined and within the same series. The specimens with gastral terga entirely punctate can be misidentified as O. opaciventris , but O. opaciventris does not have longitudinal striae on the mesonotum and its petiolar node is cylindrical, whereas in O. scalpus the node is conical.

Material examined: 81☿, 1♀. BRAZIL: Amazonas: Br-139. Km 450 (1☿) ; Manaus (14☿) . Amapá: Serra do Navio (1☿) . Pará: Benevides (7☿) ; Curuá (9☿) ; Marabá (15☿) ; Melgaço (2☿) ; Monte Dourado (1☿) ; Oriximiná (9☿) ; Pacanari (1☿) ; Paragominas (3☿) ; Parauapeba (1☿) ; Primavera (1☿) ; Terra Santa (2☿) . Rondônia: Porto Velho (5☿) . FRENCH GUIANA: Cayenne: Régina: Nouragues Natural Reserve (4☿) . Saint-Laurent-du-Maroni: Maripasoula : [Without locality] (3☿) . PERU: Cusco: Estación Biológica Villa Carmen (1☿, 1♀) . VENEZUELA: Bolívar: Kamarcabarai (1☿) .

Figures

FIGURE 1. Phylogenetic relationships of the Neotropical species of Odontomachus adapted from Fernandes et al. (2021). Colors representing the species group, yellow (hastatus group) and blue (haematodus group).

FIGURE 13. Petiolar nodes of Odontomachus workers in lateral view. A, node with posterior margin rounded and projecting laterally, dorsal portion of anterior face convex (O. allolabis); imaged by: Adrian Troya. B, node with posterior margin at most slightly convex but never projecting laterally; dorsal portion of anterior face straight to slightly concave (O. panamensis). Dash lines highlighting the shape of the dorsal portion of anterior face of petiole node.

FIGURE 14. Anterior portion of mesosoma of Odontomachus workers in dorsal view. A, central disc of pronotum with curved transverse striae, Mesopleuron without anteroventral rounded lobe (O. affinis); B, central disc of pronotum with striae forming angles anteriorly, Mesopleuron with anteroventral rounded lobe (O. panamensis). White squares with lines representing the striation pattern of pronotum and dash lines highlighting the anterior projection of mesopleuron.

FIGURE 16. Pronotum shapes and mesonotal striation of Odontomachus workers in lateral view. A, pronotum angular, mesononotum striae curved anteriorly, forming lateral concentric arcs (O. caelatus); B, pronotum in lateral view convex, mesonotum striae not forming concentric arcs (O. scalptus). White squares with lines representing the striation pattern of mesonotum in lateral view and dash lines highlighting pronotum shapes.

FIGURE 17. First gaster tergum sculpturing of Odontomachus workers in dorsal view. A, anteriorly punctate and gradually becoming longitudinally striate posteriorly (O. scalptus); B, smooth and shining (O. yucatecus).

FIGURE 27. Propleuron of Odontomachus workers in ventral view. A, propleuron with fine transverse striae (O. cupreus sp. nov.); B, propleuron smooth and shining with coarse lateral striae (O. ruginodis).

FIGURE 29.Mesosoma of Odontomachus gynesin lateral view.A, pronotumstriae regular, propleuronwithout hairs and mesopleuron without anteroventral rounded lobe (O. affinis); B, pronotumstriae irregular,propleuron with hairs and mesopleuron with anteroventral rounded lobe (O. panamensis). Arrows pointing to the propleuron. Dash lines highlighting the mesopleuron shape.

FIGURE 31. Propleuron of Odontomachus gynes in ventral view. A, propleuron with conspicuous striae (O. scalptus); B, propleuron smooth and shining with lateral striae restricted anteriorly of (O. haematodus).

FIGURE 33. Pronotal striae of Odontomachus gynes in dorsal view. A, dorsum with striae strongly curved (O. scalptus); B, dorsum with striae dorsum with striae weakly curved (O. meinerti). White squares with lines representing the striation pattern of pronotum in dorsal view.

FIGURE 34. Metascutellum striae of Odontomachus gynes in dorsal view. A, with longitudinal striae weakly impressed (O. laticeps); B, smooth and shining (O. scalptus); C, with longitudinal striae well-marked converging posteriorly (O. caelatus). Arrows pointing to the mesoscutellum.

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 64. Map of distribution of O. biumbonatus, O. opaciventris and O. xeta sp. nov. Triangles representing the typelocalities.

FIGURE 65. Odontomachus bradleyi 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 71. Map of distribution of O. scalptus, O. yucatecus and O. caelatus. Triangles representing the type-localities.

FIGURE 72. Odontomachus chelifer 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 78. Map of distribution of O. cupreus sp. nov., O. ruginodis and O. chicomendesi sp. nov. Triangles representing the type-localities.

FIGURE 79. Odontomachus cornutus worker. A, head in frontal view; B, full lateral view; C, full lateral view. Source: MZSP, imaged by: Mônica Ulysséa.

FIGURE 105. Odontomachus opaciventris 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 106. Odontomachus panamensis 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 107. Odontomachus panamensis gyne. A, head in frontal view; B, mesosoma in dorsal view; C, full lateral view.

FIGURE 108. Odontomachus ruginodis 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 109. Odontomachus ruginodis gyne. A, head in frontal view; B, mesosoma in dorsal view; C, full lateral view.

FIGURE 110. Odontomachus ruginodis male. CASENT0104177, imaged by: April Nobile, Source: AntWeb.org. A, head in frontal view; B, full dorsal view; C, full lateral view.

FIGURE 111. Odontomachus scalptus 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 112. Odontomachus scalptus gyne. A, head in frontal view; B, mesosoma in dorsal view; C, full lateral view.