Basiceros browni Probst & Brandão, 2022

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 : 12-13

publication ID

https://doi.org/10.11646/zootaxa.5149.1.1

publication LSID

lsid:zoobank.org:pub:BF98000F-04F9-4D22-9D93-4C3A2418D7EF

persistent identifier

https://treatment.plazi.org/id/F62B8F24-FF8F-E359-FF0F-FC488267DDCC

treatment provided by

Plazi

scientific name

Basiceros browni Probst & Brandão
status

sp. nov.

Basiceros browni Probst & Brandão sp. nov.

B. conjugans Brown 1974

B. convexiceps ( Mayr 1887)

B. disciger ( Mayr 1887)

B. manni Brown & Kempf 1960

B. militaris ( Weber 1950)

B. redux ( Donisthorpe 1939) = Octostruma reducta comb. n.

B. scambognathus (Brown 1949)

B. singularis ( Smith 1858)

B. tumucumaquensis Probst & Brandão sp. nov.

Identification key for female castes of Basiceros

1. Head with round vertexal margin, either presenting a medially emarginate or continuous crest ( Figs 11A View FIGURE 11 and 17A View FIGURE 17 )........ 2

- Vertexal margin continuously or moderately concave, crest absent ( Fig 13A View FIGURE 13 )...................................... 3

2. In full-face view, crest converging medially, emarginate. Sulcus interrupted by median vertexal convexity (South America, widely distributed) ( Figs 11–12 View FIGURE 11 View FIGURE 12 )................................................................. B. disciger

- In full-face view, vertexal crest continuous, separated by a broad uninterrupted sulcus (Central and N South America) ( Figs 17–20 View FIGURE 17 View FIGURE 18 View FIGURE 19 View FIGURE 20 )..................................................................................... B. militaris

3. Mandibles triangular, apices not abruptly curved ventrally, external margins convex in their basal portion ( Figs 8A View FIGURE 8 and 23A View FIGURE 23 ); basidorsal sulcus absent................................................................................ 5

- Mandibles subtriangular, apices strongly curved ventrally ( Figs 21C View FIGURE 21 , 27E View FIGURE 27 ), external margins subparallel in their basal portion; basidorsal sulcus present ( Figs 21A View FIGURE 21 , 26A–B View FIGURE 26 )............................................................... 4

4. Head pilosity majorly composed of decumbent and squamiform hairs. Mandibles with basal portion covered with squamiform hairs; basal angle of mandibles right-angled, region indistinctly translucent. Surface of antennal scrobes completely sculptured, rugo-punctuate (South America, mainly Brazil) ( Figs 21–22 View FIGURE 21 View FIGURE 22 ).................................... B. scambognathus

- Squamiform pilosity on head restricted to clypeal surface. Basal angle of mandibles broadly round, strongly translucent. Antennal scrobes matte, finely strigulate (N and NW Brazil) ( Figs 26–27 View FIGURE 26 View FIGURE 27 )...................... B. tumucumaquensis sp. nov.

5. In dorsal view, vertexal corners round; vertexal margin with short and clavate hairs. In full-face view, clypeomandibular space narrow, much shorter than half the maximum length of the clypeus ( Fig 5A View FIGURE 5 ). Specialized pilosity on mesosoma and gaster sparse ( Fig 5B View FIGURE 5 )...................................................................................... 6

- In dorsal view, vertex corners angulate; vertexal margin with long and clubber hairs in its apical portion. In full-face view, clypeomandibular space wide, longer than half the maximum length of the clypeus ( Fig 3A View FIGURE 3 ). Specialized pilosity on mesosoma and gaster dense ( Fig 3B View FIGURE 3 ).............................................................................. 7

6. Pilosity on petiolar node, postpetiole, and lateral margin of propodeum dense, whitish, and squamiform. Subpetiolar process composed of denticles varying in shape and number (N South America) ( Figs 5–6 View FIGURE 5 View FIGURE 6 )....................... B. conjugans

- Pilosity on the petiolar node, postpetiole, and lateral margin of the propodeum sparse. Subpetiolar process consisting of a single ventral process located in the anterior portion of the peduncle ( Brazilian Atlantic Forest , Santa Catarina to Bahia) ( Figs 8–9 View FIGURE 8 View FIGURE 9 )........................................................................................ B. convexiceps

7. In full face view, external margins of mandibles continuously curved from base to apex. Frontoclypeal surface smooth and shiny or slightly shagreened. Labrum lunate, anterior margin rounded (see Probst et al. 2019, Figs 2–3 View FIGURE 2 View FIGURE 3 ), lacking cleft..... 8

- In full face view, external margin of mandibles slightly sinuous. Frontoclypeal surface finely foveate-reticulate. Labrum acute and bilobed apically, lobes separated by very narrow cleft ( Probst et al. 2019, Figs 2H View FIGURE 2 and 4G View FIGURE 4 ) ( Ecuador) ( Figs 3–4 View FIGURE 3 View FIGURE 4 )............................................................................................ B. browni sp. nov.

8. Mandible dorsum with dense squamiform hairs or irregular fovea. Clypeus with decumbent and squamiform pilosity. Distal margin of labrum convex ( Probst et al. 2019, Fig 2F View FIGURE 2 ). Base of sternite of first gastral segment bearing median longitudinal elevation, generally carinate (Central and N South America, Trinidad and Tobago) ( Figs 23–25 View FIGURE 23 View FIGURE 24 View FIGURE 25 )............ B. singularis

- Basal portion of mandibles smooth and shiny. Clypeus covered with piligerous punctures. Distal margin of labrum with medially protruding knob ( Probst et al. 2019, Fig 2G View FIGURE 2 ). Base of sternite of first gastral segment lacking longitudinal carina or median elevation (Central America: Costa Rica to Honduras) ( Figs 13–14 View FIGURE 13 View FIGURE 14 )....................................... B. manni

Identification key for Basiceros males

1. 1m-cu partially closing the discal cell ( Figs 1 View FIGURE 1 , 10C View FIGURE 10 ) (but see Notes below key)......................... B. convexiceps

- 1m-cu complete, always closing the discal cell ( Figs 1C View FIGURE 1 , 14E View FIGURE 14 ); clypeomandibular space wide ( Fig 14D View FIGURE 14 ); pronotum divided into two levels, producing anteromedial concavity ( Fig 24F View FIGURE 24 )...................................................... 4

- 1m-cu absent or obsolete, discal cell absent ( Fig 1A View FIGURE 1 ); clypeomandibular space narrow or absent ( Fig 12D View FIGURE 12 ); pronotum undivided (but see Notes below key).............................................................................. 2

2. Mandibles sinuous or triangular; masticatory margins continuous; head piriform or subpiriform....................... 3

- Mandibles subtriangular, external margin strongly convex, apical tooth projected; head subhexagonal ( Fig 22D–F View FIGURE 22 )............................................................................................. B. scambognathus

3. Mesosoma shagreened, matte; mesopleuron costulate; antennal torsion exaggerated ( Fig 28 View FIGURE 28 ).. B. tumucumaquensis sp. nov.

- Mesosoma differently sculptured, mesopleuron partially smooth and shiny; antennal torsion modest................... 5

4. Mesokatepisternum covered with irregular rugulae; contrasting with the reticulate sculpture of mesoanepisternum; anterior face of pronotum slightly convex medially ( Fig 24D–F View FIGURE 24 )................................................ B. singularis

- Mesopleuron (mesokatepisternum + mesoanepisternum) reticulate; anterior face of pronotum conspicuously keeled ( Fig 14D– F View FIGURE 14 ).......................................................................................... B. manni

5. Subpetiolar process present as anterior projection, curved anterad, followed by 1–4 teeth, a lamella, or both. Mesoanepisternum with at least half of its surface smooth and shiny, mesokatepisternum smooth and shiny on about half of its length ( Fig 6D–F View FIGURE 6 )......................................................................................... B. conjugans

- Subpetiolar process absent or present as minute spiniform projection; mesopleuron sculpture different................. 6

6. Subpetiolar process absent; mesoanepisternum smooth and shiny on about 2/3 of its length; mesokatepisternum fully punctuate-reticulate ( Fig 12D–F View FIGURE 12 )...................................................................... B. disciger

- Subpetiolar process present as an anterior spiniform projection, with apex slightly curved anteriorly; mesoanepisternum smooth and shiny on about half of its length; mesokatepisternum bright on posteromedial portion ( Fig 18D–F View FIGURE 18 )......... B. militaris

Notes: Overall, not many males were available for most Basiceros species; therefore, male key should be interpreted as tentative. It is likely that the male of Basiceros browni sp. nov. keys out on step 4, given the size of worker and mandibular morphology, similar to the other species in this dichotomy. Step 1 should be read with caution, as the male of B. convexiceps was not examined, and its inclusion in the key is supported only by the diagnosis and forewing illustration provided by Emery (1924). Basiceros conjugans males can sometimes present the transversal vein 1m-cu in one of the forewings, so that the discal cell can be present and absent on the same individual.

Kingdom

Animalia

Phylum

Arthropoda

Class

Insecta

Order

Hymenoptera

Family

Formicidae

Genus

Basiceros

Loc

Basiceros browni Probst & Brandão

Probst, Rodolfo Da Silva & Brandão, Carlos Roberto Ferreira 2022
2022
Loc

Octostruma reducta

Probst & Brandão 2022
2022
Loc

B. tumucumaquensis Probst & Brandão

Probst & Brandao 2022
2022
Loc

B. conjugans

Brown 1974
1974
Loc

B. manni

Brown & Kempf 1960
1960