Basiceros manni Brown & Kempf 1960

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 : 35-42

Basiceros manni Brown & Kempf 1960

( Figs 13–15 , 30 )

Basiceros manni Brown & Kempf 1960: 177 , Figs 3 , 11 (worker, gyne): Costa Rica.

Wheeler & Wheeler 1955: 112, Plate 10, Figs 16–17 (immature of Basiceros manni identified as prepupa of Basiceros sp. Hamburg Farm, Costa Rica; collected with the type-series of what would be described as B. manni ).

Wheeler & Wheeler 1983: 607 (larva).

Type material. COSTA RICA: Limón (“ Santa Clara ”): Hamburg Farm, 1924, F. Nevermann col., n. 65065 (one worker — holotype) [ USNM] (examined) ; same data, n. 65065 (five workers, one gyne) [ USNM] (examined) ; same data, n. 30878 (three workers — paratypes) [ MCZ] (examined) ; same data (fours workers, one gyne— paratypes) [ MZSP] (examined); (eight workers — paratypes) (not examined, location unknown); Colombiana Farm , iii.1920, W. M. Mann col. (three workers) [ MZSP] (examined) ; same data (three workers — paratypes) (not examined, location unknown) . HONDURAS: Colón: Sangrelaya, v.1924, W.M. Mann col., n. 546483 (one worker — paratype) [ MCZ] (examined) ; same data (one worker — paratype) (not examined, location unknown) .

Diagnosis. Comparatively large size; color light to dark brown coloration. Specialized pilosity distributed in a double layer: a basal subdecumbent plumose, and a fine erect and clavate layers. Clypeomandibular space broad; dorsum of mandibles and clypeus with piligerous punctuations. Petiole claviform, elongated and with a depressed node. Anterior margin of first gastral sternite continuous, without longitudinal projection in the form of carina or prominence. Additionally, adult workers and gynes are usually densely covered with soil and litter particles, which adhere to the double layer of specialized hairs (see Fig1A from Probst et al., 2019).

Description. Worker (n=4). HL 1.50–1.53, HL2 1.56–1.62, HW1 1.31–1.39, MdL 0.97–1.00, SL1 1.18–1.22, SL2 1.19–1.20, PDL 0.14–0.15, A3L 0.04–0.06, AFL 0.47–0.50, FuL 1.30–1.34, EL 0.22–0.25, EW 0.19–0.22, ML 2.28–2.40, MfL 1.87–2.03, MtL 1.51–1.62, PH 0.37–0.40, PL 1.03–1.12, PW 0.36–0.39, PPL 0.59–0.65, PPW 0.56–0.65, GL 2.00– 2.09, GW 1.31–1.40, TL 8.43–8.68, CI 88–92, CS 1.42–1.44, MCI 64–66, SI 85–90, ESI 18–20, SAI2 237–253, EI1 0.28–0.33, MFI 65–70, PTI 264–283. (In bold, measurement for worker presenting slightly dilated gaster).

Size large compared to other Basiceros species. Color (when integument is visible and not densely covered with particles) brown to reddish-brown; appendices slightly lighter. Mandibles and appendages slightly reddish-brown; mandibular dorsa covered with minute piligerous punctuations; apex with short yellowish setae; interdental setae present, yellowish and brush-shaped, slightly longer than teeth. Basimandibular setae present, narrow and erect, located at the anteroventral limit of mandibular peduncle. Sparse squamiform hairs on the anterodorsal margin of the mandibular peduncle, close to the basimandibular setae. Stipes covered by fine, medium, and subdecumbent pilosity; each dorsum with a suberect hair close to its anterior margin. Labrum densely covered with piligerous punctuations bearing short and decumbent setae. Median frontoclypeal portion covered by coarse piligerous punctuations; lateral limits of clypeus with decumbent, short and squamiform yellowish hairs. Head dorsum predominantly covered by piligerous fovea bearing either squamiform or plumose-like hairs, subdecumbent; sparse long erect to suberect hairs on the anterior portion of head, more abundant near the posterolateral region of head and vertexal margin. Ventral surface of head covered by piligerous punctuations; long, erect hairs near the sides of head and squamiform hairs marginating the ventral limit of antennal scrobe. Pilosity on meso- and metasoma present as a double layer of specialized hairs. The “basal” layer is composed of yellowish and subdecumbent plumose-like hairs, present on meso- and metasoma in the following conformation: dense, surrounding the anterior margin of pronotum; slightly sparse on the dorsum of pronotum and mesonotum, dorsum and lateral of propodeum, mesopleuron near the epicnemial fossa, upper portion of mesopleuron, dorsal surface of petiolar node and postpetiole; sides of petiolar peduncle with plumose hairs, following the petiolar node; dorsum of gaster with plumose and squamiform hairs, relatively sparse, on the anterior face and anterolateral portion of procoxae and sparser on the dorsum of metacoxae. The second layer is composed of erect to suberect hairs, long and slightly clavate, present in the meso- and metasoma in the following conformation: dense on the dorsal surface of pronotum, petiolar node, postpetiole, and gaster (relatively sparse on the anterior region of first gastral sternite); one pair present on metanotal suture; 4–5 pairs on the back and sides of propodeum; slightly thinner and sparse on petiolar peduncle; two pairs on each side of anterior margin of postpetiolar sternite; present on the anterior face and anterolateral portion of procoxae; two to three pairs on the dorsum of meso- and metacoxae. Femora and tibiae covered by short, subdecumbent hairs (on tibiae, with a flatter aspect); minute appressed and clavate hairs also present on legs, more easily recognized on ventral surface of femora, tibiae (dorsum of meso- and metatibia as well) and basitarsi. Antennal pilosity unique: subdecumbent squamiform hairs on the basal lobe of scape, dense hairs, erect to suberect on scape dorsum; external margin with long erect hairs, slightly swollen on its median portion and distributed along the crenulation; short clavate and apically curved hairs also following the external margin; ventral face with short, subdecumbent setae; funicles densely covered with short, decumbent setae.

Body mostly smooth and shiny on glabrous regions. Dorsum of mandibles and clypeus covered with punctuations. Anteroventral portion of mandibles slightly alveolate. Anterior margin of labrum finely reticulate. Head dorsally rugose-foveate, irregular rugae forming fovea of different sizes; antennal fossa reticulate; antennal scrobe surface punctuate-foveate on its posterior half; head ventral face coarse and sparse punctuations. Pronotum foveate on anterior margin and sides. Mesonotum with lateral costulae, extending to the anterior face of propodeum. Gaster densely punctuate-reticulate; tergite of abdominal segments V, VI, and VII finely and densely punctate, slightly opaque, tergal margins smooth and shiny, slightly yellowish; more sparse sculpture on the first gastral sternite, especially in the anteromedial portion. Scapes finely reticulate. Legs smooth.

Head oblong, sides emarginate from the eye insertion to posterolateral region and behind the head; posterior portion of head slightly depressed, projected posteriorly; vertexal margin with rounded corners, median portion broadly concave. Cervical margin strongly carinate. Palp formula 2,2; palps strongly fused; maxillary palp slightly larger and wider than labial, with one sensillum; labial palp apically clavate, with two sensilla. Stipes subrectangular. Labrum lunate, laterally curved (apex 0.07 mm); distal margin rounded, medial knob present. Mandibles triangular; in full-face view, lateral margins slightly concave; basal margin conspicuously concave, clypeomandibular space wide; basal angle rounded, followed by about 20 slightly rounded denticles and gradually decreasing in size along the masticatory margin; in lateral view mandibular apex slightly curved ventrally. Clypeus lamellated laterally and on the anterolateral portion; anterior margin concave medially. Short frontal sulcus present separating the dorsal convexity into two parts. Compound eyes large. Carina-like rugae below eyes, projecting from the middle of the antennal fossa margin and extending to the side of the head, like an arc. Scape with lamellar basal angle slightly rounded, external margin crenulate and lamellar. Antennal fossa deep. Antennal scrobe deep on the anterior half, posterior and ventral limits weakly distinct.

Mesosoma slender; lateral profile of promesonotal complex continuously convex, strongly sloping caudad; metanotal suture wide. Mesopleuron bordered anteriorly, interrupted at the meeting of a narrow epicnemial fossa. In lateral view, anterior portion of the propodeum short and slightly oblique posteriorly, dorsal surface of propodeum slightly sloping posteriorly. Propodeal slope laterally carinate and with strong transverse lamellar carina connecting to sharp and tapered, slightly curved upwards propodeal projection. Opening of propodeal spiracle round. Bulb of metapleural gland prominent, projected and slightly narrowed; opening transversal and covered by cuticular lamella. Dorsal surface of petiolar peduncle careened longitudinally. In dorsal view, propodeal spiracle slightly projected dorsally. In lateral view, petiole long and claviform; postpetiole subcircular, subequal to the length of petiolar node. Subpetiolar process variable: from anterior process slightly curved anteriorly, followed by 4–8 spines of various sizes to slightly bifid process followed by simple or double spines and vestigial processes on the posterior portion of peduncle. In dorsal view, petiolar node ogive-shape; posterior margin of postpetiole convex and widely inserted to anterior concavity of gaster. Postpetiolar sternite conspicuously carinate anteromedially, prora present, lamellar and slightly darkened. Anterodorsal lamellar margin of gaster yellowish; median longitudinal sulcus present on first tergite, shallow and glabrous. Calcar of strigil pectinate. Meso- and metabasitarsi conspicuously long, about ¾ of tibial length. Tarsal claws simple.

Gyne (n=3). HL 1.48–155, HL2 1.53–1.62, HW1 1.33–1.40, MdL 1.00, SL1 1.19–1.22, SL2 1.18–1.20, PDL 0.15–0.16, A3L 0.05–0.06, AFL 0.48–0.50, FuL 1.31–1.36, EL 0.31–0.33, EW 0.25–0.28, LOD 0.06–0.09, MOD 0.08–0.09, OOD 0.30–0.37, ML 2.34–2.47, MSL 1.06–1.15, MSW 0.93–1.00, MLL 0.28–0.34, MLW 0.44–0.45, MfL 1.95–2.00, MtL 1.50–1.60, PH 0.35–0.40, PL 1.03–1.15, PW 0.40–0.48, PPL 0.65–0.69, PPW 0.67–0.70, GL 2.11–2.28, GW 1.50–1.53, TL 8.75–9.08, CI 89–91, CS 1.40–1.47, MCI 64–67, SI 85–92, ESI 21–27, SAI2 240–245, EI1 0.37–0.41, MTI 80–94, MLI 127–163, MFI 67–70, PTI 284–292.

Coloration and sculpture similar to conspecific workers; size slightly larger. Cephalic dorsum with three ocelli: median ocelli inserted at the top of the frontal sulcus and lateral ocelli inserted slightly above. Head pilosity as in conspecific workers. Double layer of specialized pilosity on pronotum denser than in workers. Mesoscutum almost lacking basal pilosity, only two subdecumbent hairs present, with a plumose aspect, anteriorly to each parapsis, and four hairs close to the margin of the scutoscutellar suture; erect pilosity relatively sparse, present primarily on lateral margins of mesoscutum; central portion of mesoscutum nearly glabrous. Mesoscutellum with double-layer of pilosity. Median region of metanotum with a pair of long, clavate and suberect hairs and four hairs from the basal layer with a plumose appearance. Posterior corner of mesoanepisternum, just below forewing insertion, with basal pilosity. Ventral and posterior limits of mesokatepisternum with basal pilosity, as well as the ventral portion of metakatepisternum. Dorsum of meso- and metacoxa with specialized pilosity. Remaining regions with pilosity shape and configuration similar to conspecific workers. Mesoscutum with irregular longitudinal rugae, interspersed with rugulae forming fovea of different sizes. Mesoscutellum irregularly rugo-foveate. Mesopleuron smooth, subopaque (weakly granular aspect) on most of its extension, except for foveate posterolateral portion of mesoanepisternum. Anapleural sulcus smooth. Anterior portion of petiolar peduncle finely reticulate. Gastral sculpture deeper than on workers. Other regions of the body ornamented as conspecific workers. In dorsal view, humeral angles strongly projected, dividing pronotum into two portions. Mesoscutum anteriorly rounded and slightly wedge-shaped; anteromedial carina present, short and longitudinal; posterior margin broadly convex at the meeting with the scutoscutellar suture; notauli indistinct; parapsidal lines obsolete, involved by the sculpture; parapsis subreniform, slightly deep, tegulae narrow, elongated, apical margin rounded. Pre-scutellum narrow; axillae projected posteriorly, rounded and slightly depressed. Scutoscutellar suture well-marked, transversally costulate. Mesoscutellum trapezoidal, posterior limit concave. First gastral sternite with a slightly projecting median region on basal half. Forewing type 1; hindwing with five submedian hamuli.

Male (n=2). HL 0.93–0.96, HW1 0.95, HW2 1.10, MdL 0.55–0.56, SL2 0.20–0.23, PDL 0.13–0.15, A3L 0.48, AFL 0.61–0.63, EL 0.35–0.38, EW 0.28–0.31, LOD 0.09–0.10, MOD 0.09, OOD 0.32–0.37, ML 1.88 , MSL 0.93–1.05, MSW 0.78–0.80, MLL 0.33–0.38, MLW 0.45–0.46, MfL 1.80–1.85, MtL 1.29–1.33, PH 0.25–0.30, PL 0.88–0.90, PW 0.35–0.38, PPL 0.43, PPW 0.43– 0.50, GL 1.63–1.80, GW 1.15–1.25, TL 6.35–6.45, CI 98–102, CS 0.94–0.96, MCI 58–59, SI 21–23, ESI 166–175, SAI 42–47, SAI2 32–36, EI1 42–47, EI2 120–123, MTI 78–81, MLI 123–138, MFI 51–52, PTI 300–350. (In bold: for one male, wings partially covered the lateral margin of postpetiole) .

Slightly smaller than conspecific gyne. Coloration dark brown to black, with sides of pronotum and mesoscutum, posterodorsal region of scutellum and portion of dorsum of petiole brown; postpetiole and anterior to anterolateral region of gaster testaceous; appendages brown to light brown; antennas with opaque appearance. Wings whitish to yellowish. Mandibles with long yellow hairs close to their apexes; dorsum with fine yellowish hairs and subdecumbent, slightly shorter. Head with two main types of hair: medium to short, yellow and fine, erect to suberect, sparse; and long and yellowish, generally with a curved apex and primarily on frons, vertexal, and ventral regions. The second hair type widely present throughout the body: on the dorsum of mesosoma, waist and gaster, coxae and mesokatepisternum suture. Filiform subdecumbent and short hairs present on the first gastral tergite and sternite. Antennomeres with short appressed whitish setae. Legs with suberect setae sparsely distributed among short decumbent to decumbent setae.

Body uniformly punctuate-reticulate (sculpture changing diameter and degree of impression). Distal half of mandibles smooth and shiny. Irregular longitudinal rugae on the central disc of clypeus, on head dorsum, and neck. Irregular transverse rugae near the occipital carina; on the dorsum of mesosoma; on pronotum sides, and propodeum. Mesoanepisternum shiny on its anterodorsal portion.

Head piriform; occipital margin wide and lamellar. Palp formula 1,1; palps apically subclavate and subequal; maxillary palp slightly wider than labial; apexes of palpi with long, filiform sensillum. In ventral view, mentum arrow-shaped. Labrum trapezoidal; basal region transversely striate; distal margin weakly concave; corners angled; 10–12 long and erect setae present. Mandibles triangular, elongated and gently curved apically; masticatory margin with 12–14 conical teeth, the basal and the subbasal sometimes extremely short and apical tooth slightly falcate. Clypeus with convex central disc and lateral regions depressed; anterior margin lamellar and moderately flat; frontoclypeal region excavated. Carina genal present on head side, extending posteriorly to occipital carina. Frons with arc-shaped carina above the antennal insertions and connected to frontal lobes. Antennal scrobes deep and marginally lamellar. Antennal arch expanded to posterolateral lobe, hiding the antennal bulb in full-face view. Pedicel longer than wide, third antennomere about five times longer than pedicel. Eyes large, globular, protruding from cephalic capsule; posterior margin emarginated. Ocelli pearl-shaped, projected on carinate crests.

In dorsal view, mesoscutum keel-shaped; pronotum transversally projected anterodorsad by a carinate conical or rounded process. This carina extends laterally through the pronotum, dividing it into a lower and an upper portion and producing triangular lateral flaps. Broad and partially shiny carina present on the anteromedial region of mesoscutum, extending to the dorsal region. Anterior portion of notauli separating the mesoscutum into two distinct regions: an anterior, narrow and slightly higher and obliquely convex in profile, delimited by the notauli lateroposterad and forming a projection at this region; and one posterior region, subquadrate. Notauli broad and somewhat deep, converging posteriorly on a sinuous longitudinal carina almost continuously covering mesoscutal surface. Parapsidal lines shiny; curved on anterior portion, subparallel and directed anterolaterally to the parascutal flange; posteriorly reaching the notauli. Parapsides broad, deep and reniform. Transscutal articulation convex. Axillae strongly curved posteriorly, projected and hook-shaped. Anapleural sulcus broad, deep—mesoanepisternum considerably elevated above the mesokatepisternum; scrobiculate and slit-shaped; posterior limit oblique. Scutoscutellar sulcus wide and longitudinally scrobiculate. Mesoscutellum subquadrate; posterior margin concave, crenulate and moderately depressed. In dorsal view, metanotum distinct, posterior margin projected, lateral margins lamellar. Propodeal spines short and triangular; carinate as in conspecific females. Propodeal lobes auricular. Calcar of strigil pectinate. Tarsal claws simple; short arolia present. Shape of petiole similar to conspecific females, claviform; in dorsal view, petiolar spiracle projected; anteroventral process followed by minute triangular spines. Postpetiole short; in lateral view, dorsally convex; spiracle projected; sternite with transverse lamellar prora near the anterior margin. Forewing type 1; hindwing with five to six submedian hamuli (four in one specimen, probably due to loss).

Larva. Approximate length through spiracles: 5.1 mm; profile pogonomyrmecoid: larger diameter near the middle of abdominal region, slender thorax; curved ventrally. Anus ventral, anal opening weakly convex, anal flap present. Spiracles minute. Integument of ventral region densely covered by spinules arranged in transverse rows. Pilosity moderate, denser on abdominal dorsum and ventral margin, sparse on rest of the body; long hairs—especially on part of head and ventral margin of thorax—(0.15–0.30 mm) flexuous and denticulate; alveolus and articular membrane present or not. Cranium slightly suboctagonal, occipital margin with median impression; antenna extremely minute. Clypeus protruding. Labrum bilobed, approximately three times wider than long; ventral surface densely spinous; anteroventral margin of each lobe with about six rounded sensilla; anterodorsal border with four isolated short setae resembling trichoid sensilla. Mandibles pogonomyrmecoid, long and narrow, curved; subapical tooth slightly forward to the plane of apical tooth; basal tooth strongly projected into the inner margin; anteroventral margin densely covered by subtransverse lines of short and arcuate spinules. Maxillae parabolic, dorsum with five setae, apex spinose; maxillary palps and galeae digitiform, subequal in diameter; maxillary palp with five sensilla: two apical, encapsulated, two lateral with one spinule, and one subapical spinulate; galeae with two apical spinulate sensilla. Labium covered by short transverse rows of spinules; spinules developed, capillary (about 0.02 mm) and densely covering the area surrounding the opening of the sericeous gland, shorter spinules on the rest of labium surface; labial palp papillary, with five apical sensilla (two encapsulated and three with spinules); three trichoid sensilla isolated under the labial palp, in triangular configuration. Opening of sericeous gland transversal, each side with a short and isolated sensillum. Hypopharynx densely spinous; spinules arranged in short subtransverse rows.

Etymology. This species was named after Dr. William M. Mann (1886–1960), a prominent American entomologist and myrmecologist. Dr. Mann was a doctoral student of William Morton Wheeler at Harvard University and worked at the United States Department of Agriculture (USDA) as an entomologist, conducting several expeditions, mainly in Central and South America.According to Brown & Kempf (1960: 178), Dr. Mann was the first to discover this taxon (he collected much of the type-series on expeditions in Costa Rica and Honduras) and to recognize it as a new species ( Mann 1922).

Comments. Basiceros manni is very similar to B. singularis in several characteristics, such as size, general morphology, and pilosity. Specimens of both species are easily mistaken when covered with litter and soil particles. In terms of variation, there are differences in the shape of the subpetiolar process, sculpture, and in a lesser degree in pilosity for the female castes. For males, the variation observed is mainly in the sculpture (especially in the mesosoma) and shape of the transverse keel of the anterior margin of the pronotum, whose apex ranges from conical to slightly rounded. Dietz (2004) mentions that in dorsal view it is impossible to visualize the metanotal flange on the male of B. manni , however part of the metanotum is present on specimens examined for the present study.

Most males examined here are part of nest series collected by E.O. Wilson and B. Hölldobler at La Selva Biological Station , in Costa Rica, with three specimens obtained by Wilson & Hölldobler (1986) from lab colonies during an ethological project involving those nest series .

A brachypterous intercaste have been collected for this species in Nicaragua (Dr. Michael Branstetter, pers. comm.). However, this specimen was not examined.

Distribution. This species is recorded from low elevations, in primary or low anthropogenically disturbed forests, in Costa Rica, Honduras, and Nicaragua and is likely restricted to this geographic distribution. Records for this species for Ecuador, Panama, Trinidad and Tobago, and islands in the Western Caribbean Sea (case of St. Vincent and the Grenadines) are not supported in the present study. Based on the specimens examined during this study, B. manni does not occur in Ecuador or Trinidad and Tobago, and some specimens of B. singularis examined from these two points were wrongly identified as belonging to B. manni . It was not possible to access material from the other locations mentioned and there is no way to ensure that this species occurs there. The MCZ online database highlights that those Trinidad & Tobago specimens might have unmatched specimen label information in terms of locality. Additionally, a worker collected at French Guiana by The Joint Research Unit Ecology of Guianan Forests (EcoFoG) (AntWeb specimen code ECOFOG-IT14-0106-61) and identified as B. manni by Franco et al. (2019) is actually a worker of B. singularis .

Natural History: Basiceros manni is the species of the genus with the greatest amount of behavioral ecology data, thanks largely to the work of Wilson & Hölldobler (1986) and Hölldobler & Wilson (1986) and to the information recorded on the page http://ants.biology.utah.edu/genera/basiceros/species/manni/manni.html, maintained by Dr. John Longino. Foraging workers of this species are usually covered by a thick layer of particles, as mentioned in the diagnosis. Hölldobler & Wilson (1986) speculate that the specialized double-layer pilosity acts with the layer of erect and clavate hairs capturing soil and litter particles from the environment and the layer of subdecumbent plumose hairs adhering them to the ant’s body. Individuals of B. manni present thanatosis and this behavior, added to the cryptic coloration presented by this species—a result of the already mentioned dense cover of soil particles and litter adhered to its integument—makes field observation of this dirt ant an ungrateful task.

Colonies of B. manni are usually found nesting in decayed trunks at different levels of composition, in the leaflitter located at the base of trees. Wilson & Hölldobler (1986) mention the collection of a colony nesting in a rotten fava bean of Pentaclethra macroloba partially buried in the leaf-litter. Ronald Garcia, field biologist at La Selva Biological Station in Costa Rica, share the following data on a colony nesting in an abandoned nest of what appears to be a Meliponini bee ( Fig 16 ), with the following report: “The nest was in a tree fork of a living tree, to more or less, 40 cm from the ground. The nest got my attention because the entrance looks like some stingless bees, this entrance is unbelievable! It is in the Aerial Tram, in the foothill of the Braulio Carrillo Mountain, 500m a.s.l. The size of the nest is a little more than a fist”.

Wilson & Hölldobler (1986), studying three colonies in the laboratory for about a month, report that ovaries are maximally developed in younger workers, associated with the laying of trophic eggs. In contrast, the venom gland reservoir reaches its maximum size in older workers, associated with an increase in predatory activity. These ants exhibit an exceptionally simple behavioral repertoire (Wilson & Hölldobler op. cit.). There is a temporal division of labor, with young workers acting as nurses and older workers leaving the nest in search of food. Dr. Jack Longino reports on his website (see address above) that he found this species in lowland forests of Costa Rica, usually with workers foraging alone at night or collected from litter samples submitted to a Winkler extractor. In addition, he observed a nest in a primary forest at Los Patos area in the Corcovado National Park, also in Costa Rica. The colony was on a trunk in an advanced state of decomposition at the base of a small tree, and the workers were scattered in several chambers. One chamber had almost all the immatures, in another some larvae and four empty shells of gastropods of the same species, with a long and pointed spiral (also see the natural history topic under Basiceros singularis ). Dr. Longino comments that Dr. Ted Schultz (USNM) collected a colony in a primary forest area of humid tropical forest at La Selva Station. The contents of the nest included (in addition to workers, gynes, males and immatures) a variety of empty gastropod shells, various termite abdomens and other unidentified objects reminiscent of Camponotus ( Formicidae : Formicinae) gasters. Unfortunately, Wilson & Hölldobler’s (1986) “cafeteria” experiments did not include land snails, and their captive colonies of B. manni accepted beetle larvae, centipedes, termites, and freshly killed Drosophila adults. Prey was offered directly to the larvae. The workers foraged alone and did not recruit.

This scenario of likely specialized predation on land snails was reinforced by Dr. Michael Branstetter. According to him, all colonies collected in Nicaragua had empty gastropod shells. The shells appear to belong to a “pulmonated” zonitid mollusk ( Zonitidae ), probably from the genus Glyphyalinia (Dr. Jaime Jardim pers. comm.).

Material examined. COSTA RICA: Cartago: Turrialba, summer of 1988, I. Perfecto col., n. 17—n. 326567 (2 workers) [ LACM]; Heredia: La Selva Biological Station , 4.II.1974, Talbot & VanDeVender cols., n. 326565 (3 workers) [ LACM]; 24.iii.1985, E. O. Wilson col., n. 546485 (2 workers) [ MCZ]; same data, 26.iii.1985, B. Hölldobler & E. O. Wilson cols. (2 workers, 1 male) [ MCZ]; same data, 29.iii.1985, B. Hölldobler & E.O. Wilson col., n. 546486 (3 workers, 1 gyne) [ MCZ]; same data, 29.iii.1985, B. Hölldobler & E.O. Wilson cols. (2 workers) [ MCZ]; same data, 19.xi.1985, E.O. Wilson col., (1 worker, 1 male) [ MCZ]; same data, iii.1987, E. O. Wilson col. (3 workers) [ MCZ]; same data, 14.iii.1987, E.O. Wilson col., (1 worker, 1 male) [ MCZ]; same data, 23.iii.1988, S.P. Cover col., n. 546463 (2 workers) [ MCZ]; same data, 10°26’N 84°00’W, 14.x.1991, J. T . Longino col., n. J. Longino #3078- 5, INBIO-CRI001237650 (1 worker) , [ JTL]; same data, 02.vii.1992, T. R. Schultz col., n. TRS920702-08, 538640 e 538643 (1 worker, 1 gyne, 1 male) [ USNM]; Puerto Viejo, 3.viii.1965, R . J. Hamton col., (3 workers) [ ANIC]; same data, n. 326566 (2 workers, 1 gyne) [ LACM]; Lat 10.4333 Long. -83.9833, 50m, 2.iii.1987, D. Olson col., DM029 / CASENT0914888 (1 worker) [ UCDC]; La Selva Biological Station-AntCourse 2004, 10°26’N 84°0’W, 50m, 4–14.viii.2004, B. L. Fisher, BLF10423/ CASENT0052769 (1 worker) [ CAS]. Limón (“Santa Clara”): Colombiana Farm: iii.1924, W.M. Mann col., n. 546484 (2 workers) [ MCZ]; same data (11 workers, 1 gyne) [ USNM]; Hamburg Farm: 1924, F. Nevermann col., n. 546487 (1 worker) [ MCZ] (type?); Around Guapiles, Rio Toro Amarillo, 25.ii–9.iii.1966, W.L. Brown col., n. 546481 (3 workers) [ MCZ]; same data, n. 546480 (3 workers) [ MCZ]; same data (2 workers) [ MZSP]; same data, n. 326564 (1 worker) [ LACM]; Península Osa : Corcovado : Los Patos , 01.iii.1981, J. Longino col., n. 546482 (1 worker) [ MCZ]; Puntarenas: 15 km SSW Puerto Jimenez, Lat. 8.407665 Long. -83.32788, 07.iii.2010, J. T . Longino col., n. J. Longino #6901.45/ CASENT0634078 (1 worker) [ JTL]; No label (according to Gary Umphrey : COSTA RICA: La Selva /III-14-87, E. O. Wilson col. (1 worker, 1 male) [ MCZ] . NICARAGUA: Boaco: 8km LSE de El Porton, Lat. 12.58465 Long. -85.4656, 750m, n. MGB1723 (3 workers, 1 pupa, 1 larva) [ MBPC]; Chontales: 4km NE de Cuapa , 20.iv.2011, Lat. 12.2903 Long. -85.35436, 740m, 17.iv.2011, n. MGB1735 (5 workers, a pupa, some larvae) [ MBPC]; RAAN: Parque Nacional Cerro Saslaya, Lat. 13.77065 Long. -08498018, 310m, 7.v.2011, LLAMA # Wa-D-02-44, CASENT0628761 (1 worker) [ JTL].

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 3. Basiceros browni sp. nov., holotype worker (MCZ, Ecuador: Los Ríos); A. full-face view, B. lateral view, and C. dorsal view.

FIGURE 11. Basiceros disciger, worker (MZSP, Brazil: São Paulo); A. full-face view, B. lateral view. C. dorsal view. Scale bars: A = 0.5 mm, B–C =1 mm.

FIGURE 13. Basiceros manni, worker (CASENT0914888, Costa Rica: Heredia); A. full-face view, B. lateral view, C. dorsal view. Images by Michele Esposito (CAS).

FIGURE 14. Basiceros manni, gyne (MCZ 546486, Costa Rica: Heredia) and male (MCZ, Costa Rica: Heredia); A and D. fullface 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 15. Basiceros manni, larva (MZSP, Nicaragua: Boaco); A. head in anteroventral view, B. dorsal pilosity, C. lateral view. Scale bars: A = 0.1 mm, C = 1 mm, B = 0.05 mm.

FIGURE 16. Basiceros manni colony in abandoned Meliponini nest at La Selva Biological Station, Costa Rica: Heredia; A. Exterior view of nest entrance, B. Detail of chamber with immatures below nest entrance, C. Brood chamber. Images: courtesy of Ronald Garcia.

FIGURE 17. Basiceros militaris, worker (CASENT0280778, Ecuador: Tiputini); A. full-face view, B. lateral view, C. dorsal view. Image by Estella Ortega (CAS), edited.

FIGURE 30. Distribution map of Basiceros species from the singularis clade.