Basiceros conjugans Brown, 1974

Probst, Rodolfo Da Silva & Brandão, Carlos Roberto Ferreira, 2022, A taxonomic revision of the dirt ants, Basiceros Schulz, 1906 (Hymenoptera, Formicidae), Zootaxa 5149 (1), pp. 1-75 : 16-22

Basiceros conjugans Brown, 1974

( Figs 2A–B , 5–7 , 31 )

Basiceros conjugans Brown 1974: 134 , Figs 1–2 (worker, gyne, and male), Ecuador.

Type material. ECUADOR: Limoncocha & vic.: IX–XI.1964, H. R. Hermann col., n. (one worker — holotype; 4 workers, 2 males — paratypes) [ MCZ 32179] (examined); (one alate gyne, one male — paratypes) [ NHMB] (examined) . COLOMBIA: Leticia : 7 km North of Leticia, 10–25.ii.1972, Stewart B. Peck & Jarmila Peck cols., (one worker — paratype) [ ANIC] (examined) .

Diagnosis. Dark amber to black; integument punctuate-foveate; clypeomandibular space narrow; corners of vertexal margin rounded, sulcus present medially and separating posterofrontal tumosity; petiolar node truncate anteriorly; postpetiolar and petiolar nodes usually densely covered by squamiform hairs.

Description. Worker (n=4). HL 1.25–1.28, HL2 1.25–1.30, HW1 1.28–1.31, MdL 0.72–0.78, SL1 0.84–0.89, SL2 0.89–0.94, PDL 0.11–0.13, A3L 0.03–0.05, AFL 0.36–0.38, FuL 0.97–1.00, EL 0.16–0.17, EW 0.14–0.16, ML 1.69–1.72, MfL 1.33–1.34, MtL 1.00–1.06, PH 0.38, PL 0.77–.081, PW 0.36–0.38, PPL 0.47–0.50, PPW 0.53–0.61, GL 1.59–1.63, GW 1.13–1.19, TL 6.58–6.61, CI 100–105, CS 1.27–1.28, MCI 56–62, SI 69–73, ESI 17–19, SAI2 247–252, EI1 0.23–0.26, MFI 95–97, PTI 204–216.

Body yellowish-amber to dark brown; appendages slightly lighter, yellowish to dark brown. Mandibles covered by tiny piligerous punctures, apex with short yellowish setae; interdental setae present, yellowish and filiform, subequal to teeth length. Basimandibular seta present, narrow and erect, slightly clavate. Suberect and clavate hairs in the median portion of the stipe dorsa. Frontoclypeal margin covered by spaced piligerous punctuation; lateroclypeal region with short and squamiform, decumbent yellow hairs. Occipital region predominantly covered by coarse (foveolar) piligerous punctuations; pilosity close to the posterolateral region of the head and the vertexal margin composed of whitish to yellowish, short and subdecumbent, squamiform hair. Lateral and vertexal margins of head covered by erect to suberect clavate hairs, yellowish and in the following conformation: one hair above the eyes, at the anterior limit of the antennal scrobe; four hairs on the posterolateral margin of the head, surrounding the meeting point between the posterior limit of the scrobe and the vertexal margin; one hair near the posterolateral corner of the head; four or five hairs on each side of the vertexal margin, separated by the median groove. A pair of yellowish erect and clavate hairs in the frontal region, close to the vertexal margin. Lateroventral head margin covered by whitish and squamiform hairs, subdecumbent; ventral surface of head with curved suberect and subdecumbent filiform setae, length variable. Occipital carina surrounded by four to six long and filiform hairs. Yellowish to whitish plumose pilosity, usually subdecumbent, on the mesosoma and metasoma in the following conformation: surrounding the anterolateral margin of pronotum; on the mesonotum and propodeum dorsa; marginating the sloping face of propodeum; densely on petiolar and postpetiolar node dorsa; three pairs on each side of the anterolateral region of the postpetiolar sternite; on the anterolateral region of procoxae and meso and metacoxae dorsa; on legs, from trochanters to basitarsi dorsum. Clavate hairs in the following conformation: one pair of erect hairs present on mesonotum dorsum close to promesonotal suture; erect to suberect hairs close to gastral sternite and tergite margins. Mesosternum shelf (surrounded by the epicnemial fossa) with short, filiform setae along its length. Long and filiform setae present on the anterior portion of procoxae and median portion of first gastral sternite. Thick and suberect setae present on the ventral margin of basitarsus to apex of distal tarsomere. Antennae pilosity: dorsal surface of the scape primarily covered by short, subdecumbent and squamiform hairs; external margin of scape with long, erect, and squamiform (on its apical half) hairs; funiculus densely covered with short yellowish setae; ventral margin of scape with longitudinal rows of median, curved and subdecumbent setae. Remaining of integument with thick piligerous punctuations.

Body mostly smooth and shiny on glabrous regions. Mandible and clypeus dorsa sparsely covered with punctuations. Anteroventral portion of mandibles and ventral margin of scapes finely alveolate. Head punctuate-foveate, posterolateral surface of antennal scrobe punctuate-rugose. Pronotum sparsely foveate. Dorsum of mesonotum, anterodorsal region of the propodeum, dorsal surface of the meso- and metacoxae, and dorsum of petiolar and postpetiolar node punctuate-rugose. Mesopleuron and lateral of the propodeum smooth and shiny or subopaque. Surface of propodeal declivity punctuate-rugose. Gaster densely punctuate-reticulate; tergite of abdominal segments V, VI, and VII finely and densely punctuate, slightly opaque, tergal margins smooth and shiny; sculpture sparser in the first gastral sternite, especially in the longitudinal axis of median region.Antennal scapes smooth or finely rugulose, usually shiny. Funiculi densely and finely punctuate, usually opaque. Legs smooth or superficially rugose; procoxae punctuate-foveate.

Head subtrapezoidal, sides delimited by raised margin extending from eye height to posterolateral region. Vertexal margin with gently convex corners slightly projected posterad, and with median groove dividing tumosity on the posterofrontal region of the head. Cervical margin carinate. Palp formula 2,2; palps strongly fused, giving the impression of being unsegmented; maxillary palp slightly larger in size and slightly wider than labial; labial palp apically clavate. Stipes subrectangular. Labrum cuneiform; distal margin bilobed, lobes separated by a narrow cleft, basal region canaliculate. Mandibles triangular; in full-face view, external margins slightly concave; basal margin lamellar; basal angle obtuse, followed by a masticatory margin with ten triangular teeth, apical tooth slightly curved; in lateral view mandibular apex slightly curved ventrally. Clypeomandibular space narrow. Anterior clypeal margin lamellate; anterolateral portion gently convex; anterior margin slightly concave in its median portion. Scape with slightly obtuse basal angle, followed by translucent and crenulated lamellar portion. Antennal fossa deeply impressed. Antennal scrobe comparatively deep in its lower half, posterior limit faintly distinct.

Lateral profile of mesosoma with promesonotal complex subglobular. In dorsal view, promesonotal suture practically indistinct; metanotal suture broad and strongly impressed, longitudinally costulate. Mesopleuron anteriorly marginate, interrupted at the meeting of a conspicuous epicnemial fossa. In dorsal view, propodeum subrectangular. In lateral view, anterior portion of propodeum slightly oblique posteriorly, abruptly followed by the sloping face. Propodeal slope laterally carinate and with transverse carina connecting to short, triangular and acute projections. Opening of propodeal spiracle rounded. Metapleural gland bulla prominent, protruding; opening transversal and covered by cuticular lamella. Petiolar peduncle longitudinally carinate on dorsal surface. In dorsal view, propodeal spiracle projected laterally. In lateral view, petiolar node with anterior face truncate, posterior face covered by pilosity; postpetiole slightly longer than petiolar node. Subpetiolar process highly variable: anterior process, followed by spiniform lamella or anterior process bifid, followed by spines and/or angular lamellar process.

In dorsal view, petiolar node longitudinally subrectangular; postpetiole (pilosity excluded) slightly wider than long; posterior margin convex and widely inserted in the anterior gastral cavity. Calcar of strigil pectinate. Pro-, meso-, and metabasitarsi longer than the sum of other tarsomeres. Tarsal claws simple.

Gyne (n=3). HL 1.31–1.35, HL2 1.34–1.39, HW1 1.14–1.19, MdL 0.72–0.75, SL1 0.84–0.88, SL2 0.85–0.94, PDL 0.13–0.14, A3L 0.05, AFL 0.38–0.41, FuL 0.97–1.00, EL 0.20–0.23, EW 0.16–0.19, LOD 0.07–0.08, MOD 0.08–0.10, OOD 0.37–0.43, ML 1.70–1.84, MSL 0.75–0.81, MSW 0.82–0.87, MLL 0.30–0.31, MLW 0.45–0.50, MfL 1.23–1.25, MtL 0.97–1.00, PH 0.41–0.44, PL 0.75–0.81, PPL 0.53–0.55, PW 0.21–0.34, PPW 0.5–0.63, GL 1.88–2.03, GW 1.25–1.36, TL 6.91–7.30, CI 84–88, CS 1.23–1.27, MCI 54–55, SI 74–79, ESI 22–26, SAI2 226– 232, EI1 0.31–0.32, MTI 105–116, MLI 145–160, MFI 92–95, PTI 184–188.

Color and sculpture similar to the worker; size slightly larger. Cephalic dorsum with three ocelli: median ocelli inserted slightly below and lateral ocelli inserted just above a pair of clavate and erect hairs. Head and waist pilosity as in workers. Pilosity of anterolateral margin of pronotum denser and longer than in workers. Whitish and subdecumbent, squamiform hairs close to humeral angles and surrounding the posterior limit of pronotum; short and sparse on the dorsum of mesoscutum; on the scutoscutellar sulcus axillae; on the dorsum of mesoscutellum; a suberect pair on the metanotal flange. Whitish erect to suberect and clavate hairs on each side of pronotum, one pair close to the pronotal suture; a pair on the metanotal flange; narrower and arranged in eight pairs on the dorsum of mesoscutum; one pair in each parapside; one on each lateral portion of axilla, one on the lateral margin of mesoscutellum. Hairs on gaster more abundant than on workers. In dorsal view, mesoscutum anteriorly rounded, slightly cuneiform, posterior margin slightly convex in the meeting with the scutellar suture; notauli indistinct; parapsidal lines narrow and inconspicuous, involved by the sculpture; shallow, parapsis rudimentary; tegula narrow, apical margin rounded. Prescutellum narrow; axillae projected posteriorly, rounded and slightly depressed. Scutellar sulcus well marked. Mesoscutellum transversely subrectangular, posterior limit concave. Dorsal face of propodeum strongly inclined. In lateral view, anapleural sulcus broader anteriorly at the connection with the epicnemial fossa, narrowing posteriorly. First gastral sternite with median region slightly projecting on its basal half. Forewing mostly conforming to type 2, transversal vein 1m-cu present as an appendage; hindwing with fix submedian hamuli.

Male (n=2). HL 0.85–0.93, HW1 0.77–0.81, HW2 0.63 –0.95, MdL 0.40–0.43, SL2 0.15–0.21, PDL 0.10–0.13, A3L 0.28–0.31, AFL 0.44–0.48, EL 0.30–0.33, EW 0.23–0.26, LOD 0.09, MOD 0.08–0.09, OOD 0.31–0.34, ML 1.43–1.59, MSL 0.75–0.85, MSW 0.70–0.78, MLL 0.30–0.34, MLW 0.43–0.48, MfL 1.15–1.25, MtL 0.83–0.88, PH 0.25–0.30, PL 0.63–0.70, PW 0.23–0.33, PPL 0.31–0.36, PPW 0.34–0.40, GL 1.36–1.50, GW 0.98–1.10, TL 5.01–5.41, CI 84–91, CS 0.81–0.87, MCI 44–47, SI 19–28, ESI 150–200, SAI 50–70, SAI2 34–50, EI1 0.65–0.71, EI2 80– 124, MTI 87–98, MLI 136–141, MFI 61–67, PTI 231–250. (In bold: measurements suffered influence of prolegs partially covering compound eyes).

Size slightly smaller than the conspecific gyne. Color black; postpetiole and first gastral tergite disc brown; appendages yellowish to light brown. Apical portion of mandibles smooth and yellowish. Wings yellowish to brown. Mandible dorsa and apex with long and fine yellow hairs, semi-erect to subdecumbent, slightly longer on apical portion of mandibles. Head with two main types of hair: medium and fine, yellow and subdecumbent, primarily on the frontal disc of clypeus; long and whitish to yellowish (sometimes with a curved apex), present along the genal carina, on the vertexal margin, and the ventral surface. The second hair type widely present throughout the body: on mesosomal dorsum, waist, and gaster, exceptionally long on the ocellar region, on procoxae and dorsum of petiole. Antennomeres with short and yellowish appressed setae. Legs with medium and yellowish decumbent to decumbent setae.

Body uniformly punctuate-reticulate, sculpture varying on diameter and degree of impression. Apical portion of mandibles smooth and shiny. Irregular longitudinal rugae present in the neck to faintly on the vertex margin, close to occipital carina. Irregular transverse rugae on the dorsum of mesoscutellum, on the metakatepisternum and propodeum. Mesoanepisternum slightly darker, smooth and shiny over a little more than half its length; posteromedial portion of mesokatepisternum smooth and shiny. Dorsolateral rugae present on the anterior portion of petiolar node.

Head subpiriform; occipital margin wide and lamellar, medially concave. Palp formula 1,1; palpi slightly swollen and flattened on apical half; maxillary palp appears to be slightly longer and wider than labial. Mentum narrow and triangular. Stipes subrectangular. Labrum elongated, distal margin bilobed; approximately ten long setae present. Mandibles triangular, curved towards their apexes; masticatory margin with nine teeth of similar size. Clypeus with central disc convex, slightly elevated; lateral regions depressed; anterior margin lamellar and slightly concave. Postgenal carina present, shaped like a longitudinal line, smooth and shiny just after the supraclypeal region and extending posteriorly on the head until close to the upper limits of the antennal scrobes. Antennal arch medially expanded as swollen posterolateral lobe, completely hiding the antennal bulb in frontal view. Antenna pedicel longer than wide, third antennomere about three times longer than the pedicel. Eyes large and globular, protruding from the cephalic capsule. Ocelli caramel-colored, projected. Mesoscutum cuneiform in dorsal view, elongated anteriorly. Smooth and shiny carina present on the anteromedial region of mesoscutum, extending as a line near the dorsal margin. Notauli V-shaped, converging at the center of mesoscutellum and extending as a median longitudinal sulcus to the line of the scutellar suture. Parapsidal lines shiny; curved on its anterior portion, subparallel and directed anterolaterally to the parascutal flange. Parapsis oval. Transcutellar sulcus slightly angled medially. Axillae protruded, strongly curved posteriorly; hook-shaped. Anapleural suture broad, strongly impressed and scrobiculate—mesoanepisternum conspicuously elevated relative to mesokatepisternum. Scutoscutellar sutured narrower compared to other Basiceros males; smooth and with a median transverse carina. Mesoscutellum subrectangular; posteromedially depressed; posterior margin strongly concave and depressed. Metanotum with posterior margin lamellar. Propodeum armed with triangular, laminar projections. Propodeal lobes auricular. Calcar of strigil short and pectinate. Tarsal claws simple; short arolia present. Petiole claviform; in lateral view petiolar node low; petiolar spiracle projected in dorsal view. Subpetiolar process with anteriorly curved projection followed by 1–4 teeth or with lamella or both (as Brown (1974) mentioned: “very inconstant”). Postpetiole approximately half the length of petiole in lateral view. In dorsal view, petiolar node rounded. Forewing type 1 or type 2. Hindwing with six submedian hamuli.

Larva (first description, based on three specimens). Approximate length through spiracles: 3.7 mm; profile pogonomyrmecoid: largest diameter near middle of abdominal region, thoracic region slender than abdominal region; curved ventrally. Anus ventral, anal opening weakly convex. Spiracles small. Integument of ventral region densely covered by spinules arranged in transverse rows. Pilosity moderately dense, denser near abdominal apex, sparse on the rest of the body; hairs long (0.10–0.30 mm), flexible and indented; alveolus and articular membrane present or not. Cranium suboctagonal, antennae very small. Clypeus protruded. Labrum bilobed, slightly wider than twice its length; ventral face densely spinulose; anteroventral margin of each lobe with about 4–5 rounded sensilla; anterodorsal border with two isolated short setae resembling trichoid sensilla. Mandibles pogonomyrmecoid, long and narrow, medially curved; apical tooth slightly curved and with rounded apex, separated from other teeth by conspicuous diastema; two protruding teeth projected from the basal margin; anteroventral margin with spiculae in short and arcuate subtransversal lines. Maxillae parabolic, dorsum with 4 setae, apex spinulose; maxillary palps digitiform, elongated and narrow, with three apical encapsulated sensilla and one spinulose lateral sensillum; galea digitiform, with two apical encapsulated sensilla. Labium covered by short transverse rows of spinules; those developed, capillary (about 0.02 mm) and densely covering the rest of labium surface; labial palp papillary, with five apical sensilla (two encapsulated and three with spinules); opening of sericeous gland transversal, bearing a short isolated sensillum on each side. Hypopharynx spinulose.

Etymology. from the Latin conjugant - ( conjugans ), present participle of the verb conjugare, meaning “connecting”, “uniting”. Such an epithet is undoubtedly a reference to the intermediate morphology of this species among the other taxa of the then considered separate genera Aspididris and Basiceros . When describing the species, Brown (1974) refers to B. conjugans as the “additional intergradient” and formally synonymizes Aspididris under Basiceros .

Comments. Brown (1974), based on the shape of the vertexal margin and the clavate hairs distributed along its length, speculates on the intermediate state of B. conjugans within the genus when comparing it to B. disciger and B. manni . Basiceros conjugans presents what Brown categorizes as “an intermediate pattern of transversal ridges on the vertexal margin”; the same for the concentration of clavate hairs in this region. The following could be added to the list of “intermediate” characters: head shape, more elongated than in B. disciger and B. militaris ; the presence of a narrow clypeomandibular space, separating the clypeus from the basal region of the mandibles—absent in B. disciger and B. militaris and broad in B. manni and B. singularis ; and the specialized pilosity (clavate or subplumose), denser than observed for B. disciger and B. militaris —what could explain the greater tendency for soil and vegetation particles to adhere to females of B. conjugans compared to other taxa from the disciger clade. In addition, males of B. conjugans may present a complete 1m-cu vein, closing the discal cell. This characteristic is found in Basiceros males from the singularis clade, but it is absent in other males from the disciger clade, confirming that this species might have a combination of characteristics of these two clades.

In terms of variation, workers of B. conjugans present variable integumentary and pilosity colorations, depth of the metanotal suture, shape of the petiolar node and subpetiolar process, integumentary sculpture (degree of impression and brightness), and size. However, together with B. convexiceps , it is one of the most morphologically “cohesive” species. The specialized pilosity pattern (with emphasis on the vertexal margin, back of propodeum, petiolar node, and dorsal margin of the postpetiole) and head and mesosoma morphologies are present similarly on all examined specimens. It is important to mention that the pilosity is present as described for specimens in good conditions, but some specimens—probably resultant of abrasion—lack several special hairs, such as those on the vertexal margin and the back of the mesoscutum (in the case of gynes).

The holotype has a reddish-brown color and is probably a young worker, as other examined specimens from Ecuador are darker colored. Other Ecuadorian specimens have a similar reddish-brown color, usually within series containing darker specimens. The most extraordinary integumental coloration comes from Peruvian specimens collected in Napo, close to the border with Ecuador: a clear yellowish-amber and very bright integument. Regarding the morphology of the subpetiolar process, in the case of gynes and workers, it varies from: a set of two spines, composed of an angulate anteroventral “boot”-shaped or spine, followed by a lamella; a process with an anteroventral projection followed by 5–6 spines; or by lamellar processes and/or fused spines. The male subpetiolar process varies from an anterior curved process to a set of several short spines followed by a lamellar process at the end of the peduncle’s ventral margin.

In addition, some specimens were partially covered by litter and soil particles, making it difficult to see certain structures, such as the ocelli on the gynes. Males may show variation in the forewing venation, with the length of transversal 1m-cu vein present differentially in the same specimen: it may be absent or present as a short appendix in one wing while present as complete in the other wing.

Distribution. This species is known for the Eastern Amazonian rainforests in South America and from secondary forests in Trinidad —more precisely, at the Arena Forest Reserve, place of a sustainable management system of a tropical forest (Shelterwood System), developed in the 1950s. For the present study, B. conjugans distribution is considerably expanded based on new records for the Brazilian states of Pará and Rondônia, Peru, and Guyana. Basiceros conjugans was known to Brazil based on a single worker collected in Porto Walter ( Delabie 2000), a municipality in the state of Acre close to the Peruvian border. That worker was found in the stomach contents of the amphibian Bufo typhonius (Linnaeus, 1758) (= Rhinella margaritifera (Laurenti, 1768)) . The material examined here indicates that this species possibly occurs in southern Venezuela and the Brazilian states of Roraima and Amazonas.

Natural history. Little is known about the biology of this dirt ant. Specimens were manually collected from rotten logs or leaf litter samples, with most of the examined material collected via Winkler extractors. In 2012, as a student of the Neotropical Ant Course at the Sachavacayoc Center ( Peru, Madre de Díos), one of us (RSP) collected part of a colony nesting in a rotten trunk. Next to the collected material (larvae, a pupa, few workers) was an unidentified gastropod shell, the body of a turtle ant worker ( Cephalotes sp. ), and two cephalic capsules: one from an unidentified trap-jaw ant worker ( Odontomachus sp. ) and one from the termite Uncitermes teevani ( Termitidae , Syntermitinae ). These observations, associated with a cryptic life habit, suggest that B. conjugans might feed on carcasses of other arthropods. It cannot be ruled out that this species might prey on termites, which has occasionally been observed for other Basiceros (see natural history accounts for Basiceros manni and B. singularis ). Uncitermes teevani does not build a nest and lives in the interstices of litter (Dr. Maurício Moura, pers. comm.).

Material examined. BRAZIL: Acre: Porto Walter, 08°15’31.2”S 72°46’37.1”W, 05.ii–17.iv.1997, J. Caldwell col. (1 worker) [ CEPEC]; Pará: Parauapebas , 6°20’41.34”S 49°58’29.06”W, 08–22.v.2013, C.A. R . Souza et al. col., CARSTE 6040 (1 worker) [ MZSP] ; Rondônia: Porto Velho, Área Caiçara , 09°26’14.6”S 64°49’58.2”W, 27.iii– 09.iv.2011, R. R. Silva & Albuquerque, E.Z. cols. (1 worker) [ MZSP], 04–18.ix.2012, Ulysséa, M. A. & Prado, L. P. cols. (1 worker) [ MZSP]; Porto Velho, Área Abunã , 09°35’46”S 65°20’56”W, 27.iii–09.iv.2011, R. R. Silva & Albuquerque, E.Z. cols. (2 workers) [ MZSP], 09°35’43.7”S 65°20’55.7”W, 27.iii–09.iv.2011, R. R. Silva & Albuquerque, E.Z. cols. (1 worker) [ MZSP] . COLOMBIA: Nariño Orito, Territorio Kofan, 00°30’N 77°13’W, 1000m (4 workers) [ IAVH] . ECUADOR: Coca : v.1965, La Peña col., n. 546612 (1 male) [ MCZ] ; Napo: 20km S de Tena , 600m, 11.vii, Stewart B. Peck & Jarmila Peck cols., LACM 326569 (1 worker) [ LACM]; Limoncocha, 250 m, 18.vi.1976, Stewart B. Peck & Jarmila Peck cols., n. 546454 (1 worker) [ MCZ]; Jatun Sacha, 7km ESE Puerto Misahuallí, Lat. -1.0667 Long. -77.6167, 400m, 05.viii.1991, P. S. Ward col., PSW11365-31 (1 worker) [ UCDC]; Puerto Misahuallí , 15.vii.1978, G.J Umphrey col., GJU 0774, (2 workers) [ GUPC]; same data (1 worker) [ MZSP]; same data (1 worker) [ MNH]; same data (1 worker) [ RSPPC] . Pichincha: 4 km E Santo Domingo de los Colorados, 08.vii.1976, Stewart B. Peck & Jarmila Peck cols., n. 546456 (1 worker) [ MCZ]; 47 km S Santo Domingo, Rio Palenque Station , 700m, 18–30.v.1975, Stewart B. Peck & Jarmila Peck cols., n. 546462 (1 worker) [ MCZ]; pr . Morona Santiago: Los Tayos, 3.viii.1976, Tjitte de Vries col. (1 worker) [ MZSP]; Zamora: Chichipe , Copalinga , Lat. -4.091222 Long. -78.96069, 1030m, 30.ix.2009, T . Delsinne & Arias-Penna, T . cols. (1 worker) [ MZSP]; Jardin Botánico , Estación El Padmi, 18.7km NEE Yantzaza, 835m, 3.74572°S 78.61436°W, 15.vi.2014, T . Delsinne & Arias-Penna, T . cols. (1 worker) [ MZSP] ; GUYANA: Upper Takutu-Upper Essequibo: Acaraí Mountains, near New Romeo Camp , 1°20’842”N 58°57’496”W, 735m, 16.x.2006, C. J. Marshall, TRS 061016- LS04 (2 workers) [ USNM]; 1°20’896”N 58°57’491”W, 753 M, J. Sosa-Calvo col., TRS 061016- LS06 (1 worker) [ USNM]; 1°23’06”N 58°56’789”W, 294m, T. R. Schultz & J. Sosa-Calvo cols., JSC061010- LS09 (1 worker) [ USNM]; 1°23’191”N 58°56’808”W, 303m, T. R . Schultz & J. Sosa-Calvo cols., JSC061010- LS03 (1 worker) [ USNM]; 1°23’137”N 58°56’787”W, 314m, T. R . Schultz & J. Sosa-Calvo cols., JSC061010- LS06 (2 workers) [ USNM]; 1°23’122”N 58°56’761”W, 273m, T. R . Schultz & J. Sosa-Calvo cols., JSC061010- LS08 (1 gyne) [ USNM]. PERU: Cusco: Estación Biológica Villa Carmen, Lat. -12.863717 Long. -71.400528, 590m, 6.viii.2013, Corrie S. Moreau col., CSM 2987 (5 workers, brood) [ MZSP, RSPPC] ; Loreto: Jenaro Herrera , 04°53’55”S 73°39’00”W, 121m, 13–23.i.2011, Neotropical Ant Course (1 worker) [ MZSP] ; Madre de Díos: Sachavacayoc Center , 12°49’36.5”S 69°22’14.4”W, 209m, 19–31.vii.2012, R . Feitosa & R . Probst cols. (7 workers, brood) [ MZSP]; Sachavacayoc Center ( Castanhal ), 12°51’21”S 69°21’43”W, 210m, 19–31.vii.2012, R . Feitosa col. (1 worker) [ JCPC]. Tambopata : 15 km NE Puerto Maldonado, 22.vi.1989, S. P. Cover & J. Tobin cols., LACM 326568 (2 workers) [ LACM]. Tambopata Research Center: Lat. -13.14048 Long -69.62108, 318m, viii.2001, D. Feener col., TRC-S05- R1 C09/ CASENT0637530 (1 gyne) [ JTL); Lat. -13.1381 Long. -69.62767, 289m, ix.2001, D. Feener col., TRC-S10- R1 C01/ CASENT0637518 (1 worker) [ JTL). TRINIDAD & TOBAGO: Arena Forest Reserve : 1.05km SSE de San Rafael, 10°57’N 61°26’W, R. R. Snelling col., LACM 326570 (1 worker) e LACM 326571 (1 worker) [ LACM].

Figures

FIGURE 1. Wing venation of Basiceros males. A. forewing and B. hindwing of B. conjugans (RSPPC, Peru). C. forewing of B. manni male (MCZ, Costa Rica: Heredia). Fused veins are indicated with a plus sign and crossveins by a dash. Cell names (in white) are indicated in italics. Scale bars: 1 mm.

FIGURE 2. Morphological measurements of Basiceros species; A. lateral view of worker and B. dorsal view of alate gyne of B. conjugans (MCZ546461, Peru: 15 km NE Puerto Maldonado), EL: Eye Length, PDL: Pedicel Length, AFL: Apical Flagellomere Length, ML: Mesosoma Length (= Weber’s Length), MTL: Metatibia Length, PTH: Petiole Height, PTL: Petiole Length, PPL: Postpetiole Length, MSL: Mesoscutum Length, MSW: Mesoscutum Width, MLL: Mesoscutellum Length, MLW: Mesoscutellum Width, MFL: Metafemur Length, PTW: Petiole Width, PPW: Postpetiole Width, GW: Width of gaster. C. full-face view of Basiceros browni sp. nov., paratype worker (MZSP, Ecuador: Pichincha, Otongachi), HL: Head Length, HL2: Head Length 2, HW1: Head Width 1, MdL: Mandible length, SL1: Scape Length 1, SL2: Scape Length 2, FuL: Funiculus Length. D. full-face view of male of B. manni (MCZ, Costa Rica: Heredia), HW2: Head Width 2, LOD: Lateral Ocellus Length, MOD: Median Ocellus Length, OOD: Oculo-ocellar distance, A3L: Antennomere 3 Length. Figures not to scale.

FIGURE 5. Basiceros conjugans, holotype worker (MCZ 32179, Ecuador: Limoncocha); A. full-face view, B. lateral view, and C. dorsal view. Scale bars: A = 0.5 mm, B–C = 1 mm.

FIGURE 6. Basiceros conjugans, paratypes gyne and male (MCZ 546463, Ecuador: Limoncocha), Ecuador: Limoncocha); A and D. full-face view, B and E. dorsal view, C and F. lateral view. Scale bars: A, D = 0.5 mm, B, C, E, F =1 mm.

FIGURE 7. Basiceros conjugans, larva (MZSP, Peru: Madre de Dios); A. head in anteroventral view; B. head in oblique view; C. lateral view; D. dorsal pilosity; E. anus. Scale bars: A, B, E = 0.1 mm; C = 0.5 mm; E = 0.05 mm.

FIGURE 31. Distribution map of Basiceros species from the disciger clade (in part).