Key to Afrotropical Pheidole pulchella-group species

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A Key to the Afrotropical Pheidole puchella-group species

Fischer, G., Hita Garcia, F. & Peters, M.K. 2012. Taxonomy of the ant genus Pheidole Westwood in the Afrotropical zoogeographic region: definition of species groups and systematic revision of the Pheidole pulchella group. Zootaxa 3232: 1-43. PDF

A description of the group can be found here: pulchella group.

The key includes minors and majors.

1

  • Minor: in full-face view lateral head margin with abundant projecting hairs, both anterior and posterior of eye-level (Fig. 2A). Minor and major: color yellow to orange . . . . . 2
  • Minor: in full-face view either without laterally projecting hairs at head margin (Fig. 2C), or if present, then only posterior of eyes (Fig. 2B). Minor and major: color light, reddish brown to very dark brown, sometimes black . . . . . 4
FIGURE 2 A) Pheidole christinae, B) Pheidole batrachorum, C) Pheidole glabrella. Full-face view of minor workers: examples of laterally projecting hairs anterior and posterior of eye-level (A), posterior of eye-level only (B) and completely without (C).

2

return to couplet #1

  • Minor: head evenly rounded at sides and posterior margin; head relatively shorter (CI: 82–90); pilosity on scape and metatibia decumbent (Fig. 3A). Major: antennal scrobe conspicuous; sides of head without laterally projecting hairs in full-face view (Fig. 3B). (Congo, Gabon) . . . . . Pheidole pulchella
  • Minor: sides of head posterior of eyes sublinear and elongated; head relatively longer (CI: 73–84); pilosity on scape and metatibia suberect-erect (Fig. 3C). Major (of P. heliosa; major of P. christinae unknown): antennal scrobe absent or inconspicuous; head in full-face view with laterally projecting hairs (Fig. 3D) . . . . . 3
FIGURE 3 A, B) Pheidole pulchella. Full-face view of minor and major worker: showing sides of head rounded towards posterior head margin in the minor (A), and presence of antennal scrobe and absence of laterally projecting hairs in the major (B). C, D) Pheidole heliosa. Full-face view of minor and major worker: illustrating elongated posterior sides of head in the minor worker (C), and absence of antennal scrobe and presence of laterally projecting hairs in major worker (D).

3

return to couplet #2

  • Minor: head, scapes and legs very long (CI: 73–76, SI: 162–174, FI: 206–213); occipital carina broadly extended and collarlike; standing hairs acute and very abundant (Fig. 4A), present also on lower meso- and metapleuron, visible in dorsal view. Major: head without antennal scrobe; in full-face view hairs projecting beyond lateral margin. (Cameroon, Ivory Coast). (Major of P. christinae unknown) . . . . . Pheidole heliosa
  • Minor: head, scape and legs relatively shorter (CI: 79–84, SI: 143–164, FI: 175–198); occipital carina narrow, not collar-like; standing hairs often apically truncated or split, generally less abundant (Fig. 4B), absent on lower meso- and metapleuron. (D.R. Congo, Gabon, Uganda) . . . . . Pheidole christinae
FIGURE 4 A) Pheidole heliosa. Lateral view of minor worker, illustrating mesosoma with long second mesonotal process, highest point of dorsopropodeum immediately at metanotal groove and postpetiole shape spheroidal. B) Pheidole christinae. Lateral view of minor worker, showing shorter second mesonotal process, highest point of dorsopropodeum midway between metanotal groove and base of spines, postpetiole shape not spheroidal.

4

return to couplet #1

  • Minor: head with several relatively long, laterally projecting hairs posterior of eye-level (Fig. 5A). Major: either posterolateral lobes partly smooth and shiny and scape with erect hairs in addition to decumbent pilosity (Fig. 5B), or posterolateral lobes uniformly punctate with weak rugulae and posterior dorsopropodeum with oblique to longitudinal rugulae (Fig. 5C) . . . . . 5
  • Minor: head completely without or at most with one or two moderately long projecting hairs near eyes or towards posterior margin (Fig. 5D). Major: head sculpture various; scape never with several erect hairs in addition to appressed or decumbent pilosity (Fig. 5E); sculpture on posterior dorsopropodeum transversely rugulose, punctate or smooth, and never with oblique or longitudinal rugulae (Fig. 5F) . . . . . 7
FIGURE 5 A) Pheidole setosa. Minor worker in full-face view: illustrating head margin with several laterally projecting and long hairs; B) Pheidole darwini Major worker in oblique frontolateral view: scape with erect, long hairs in addition to decumbent pilosity; C) Pheidole batrachorum. Major worker in dorsal view: pronotum with several oblique to longitudinal rugulae. D) Pheidole nimba Bernard. Minor worker in full-face view: illustrating head margin with a maximum of two laterally projecting and short hairs; E, F) Pheidole glabrella. Major worker in oblique full-face view and in dorsal view: illustrating uniform scape pilosity without additional erect hairs (E) and transverse rugulae on dorsal pronotum (F).

5

return to couplet #4

  • Minor: head shape elliptical (CI: 79–89); posterior margin relatively narrow and evenly convex; occipital carina with weak median impression; scapes moderately long (SI: 139–172), with pilosity uniformly suberect or decumbent (Fig. 6A). Major: posterolateral lobes partly smooth and shiny and scape with erect hairs in addition to decumbent pilosity, or posterolateral lobes uniformly punctate with weak rugulae and posterior dorsopropodeum with oblique to longitudinal rugulae. (Major of P. setosa unknown) . . . . . 6
  • Minor: head shape broadly rounded, posterior margin not evenly convex (CI: 87–90); occipital carina without median impression; scapes relatively shorter (SI: 129–135); scape pilosity decumbent with additional suberect hairs on outer edge (Fig. 6B). (D.R. Congo) . . . . . Pheidole setosa
FIGURE 6 A, B) Pheidole darwini and Pheidole setosa Full-face view of minor workers: illustrating narrow posterior head margin and uniformly subdecumbent to suberect scape pilosity (A) versus wider posterior head margin and scape with erect to suberect hairs additional to decumbent pilosity (B).

6

return to couplet #5

  • Minor: head relatively narrow (CI: 79–86); scapes long (SI: 153–172); scape pilosity uniformly decumbent; face almost completely and distinctly punctate (Fig. 7A). Major: posterolateral lobes uniformly punctate with some weak rugulae; scape with uniformly appressed to decumbent pilosity; posterior dorsopropodeum with oblique to longitudinal rugulae (Fig. 7B). (Central African Republic, D.R. Congo, Gabon) . . . . . Pheidole batrachorum
  • Minor: head relatively wider (CI: 84–89); scapes slightly shorter (SI: 139–160); scape pilosity uniformly subdecumbent to suberect; face smooth and shiny, hexagonally microsculptured to very faintly punctate (Fig. 7C). Major: posterolateral lobes partly smooth and shiny; scape with some erect hairs additional to decumbent pilosity; posterior dorsopropodeum weakly to superficially rugulose-punctate (Fig. 7D). (Cameroon, Central African Republic, Gabon) . . . . . Pheidole darwini
FIGURE 7 A, B) Pheidole batrachorum. Full-face view of minor worker and dorsal view of major worker: showing distinctly punctate face of the minor worker (A) and head with distinctly sculptured posterolateral lobes, and posterior dorsopronotum with longitudinal rugulae for the major worker (A). C, D) Pheidole darwini. Full-face view of minor and dorsal view of major worker: illustrating superficially punctate (hexagonally microsculptured) face in the minor worker (C) and head with smooth & shiny posterolateral lobes, and posterior dorsopronotum without longitudinal, or oblique rugulae for the major worker (D).

7

return to couplet #4

  • Minor: sculpture variable, but head and mesosoma never completely and coarsely punctate; at least medially between eyes and on posterior dorsopronotum superficially sculptured to smooth and shiny (Fig. 8A). Major: head sculpture variable, but never distinctly punctate on frons, vertex and posterolateral lobes; gaster never entirely shagreened. (Major of P. nimba unknown) . . . . . 8
  • Minor: head and mesosoma almost completely and coarsely punctate (Fig. 8B) . . . . . Pheidole nimba
FIGURE 8 A, B) Pheidole dea and Pheidole nimba. Minor workers with dorsal view of head and promesonotum: illustrating smooth to superficially punctate areas medially between eyes and posteriorly on dorsal promesonotum (A) versus uniformly expressed sculpture in face and on promesonotum (B).

8

return to couplet #7

  • Minor: head longer than wide (CI: 85–95), posterior margin roundly or slightly convex (Fig. 9A); scapes and mandibles moderately long (SI: 123–150, MDI: 72–79). Major: posterolateral lobes variably sculptured, never smooth and shiny; face with distinct and moderately long to long rugae; dorsal promesonotum mostly weakly to superficially sculptured (Fig. 9B) . . . . . 9
  • Minor: head almost as wide as long (CI: 94–98), posterior margin not convex, but almost straight (Fig. 9C); scapes and mandibles shorter (SI: 114–121, MDI: 69–73). Major: posterolateral lobes smooth and shiny; face with weak and relatively short rugae; dorsal promesonotum mostly smooth and shiny, with superficial rugulae anteriorly (Fig. 9D). (Ghana, Ivory Coast) . . . . . Pheidole rebeccae
FIGURE 9 A, B) Pheidole glabrella. Full-face view of minor worker (A), showing rounded head shape and rounded occipital margin; dorsal view of major worker (B), illustrating obliquely rugulose-punctate sculpture on posterolateral lobes, and regular transversely rugulose-punctate sculpture on dorsopronotum. C, D) Pheidole rebeccae. Full-face view of minor worker (C), showing wider head shape and less convex head margin; dorsal view of major worker (D), illustrating smooth and shiny posterolateral lobes, and dorsopronotum grading from anteriorly superficially rugulose to posteriorly mostly smooth & shiny.

9

return to couplet #8

  • Minor: long or moderately long hairs completely absent on mesosoma and waist segments; petiole and postpetiole without laterally projecting hairs in dorsal view; metatibia pilosity appressed; second mesonotal process and sculpture on propodeum reduced; metanotal groove wide in profile (Fig. 10A); spines long (PSLI (mean): 33). Major: scape and metatibia pilosity fine and inconspicuous, mostly fully appressed (Fig. 10B); long standing hairs absent on promesonotum. (Cameroon, Central African Republic, Gabon) . . . . . Pheidole glabrella
  • Minor: moderately long hairs at least present on waist segments, sometimes also on promesonotum; on petiole and/or postpetiole some laterally projecting hairs in dorsal view; metatibia pilosity decumbent; second mesonotal process and sculpture on propodeum not reduced; metanotal groove relatively narrow in profile (Fig. 10C); spines slightly shorter (PSLI (mean): 29). Major: scape and metatibia pilosity conspicuous and decumbent (Fig. 10D); standing hairs often present on promesonotum . . . . . 10
FIGURE 10 A, B) Pheidole glabrella. Lateral view of minor worker (A), showing reduced second mesonotal process and sculpture on propodeum, metanotal groove relatively wide; full-face view of major worker (B), showing scape pilosity appressed. C, D) Pheidole semidea. Lateral view of minor worker (C), illustrating well-defined second mesonotal process and sculpture on propodeum, metanotal groove narrower; full-face view of major worker (D), showing decumbent scape pilosity.

10

return to couplet #9

  • Minor: posterior head margin roundly convex; face and dorsal promesonotum mostly superficially punctate to punctate; second mesonotal process not raised above the level of dorsopropodeum (Fig.11A); postpetiole relatively short (PpLI: 155–223). Major: posterolateral lobes of head longitudinally rugose (Fig. 11B), with spaces between rugae weakly to superficially punctate; second mesonotal process at same level as dorsopropodeum. (D.R. Congo, Kenya, Tanzania, Uganda) . . . . . Pheidole dea
  • Minor: posterior head margin weakly convex, with small median impression; face and promesonotum smooth and shiny, with very few superficial punctures; in lateral view second mesonotal process distinctly raised above the level of dorsopropodeum (Fig. 11C); postpetiole relatively longer (PpLI: 126–167). Major: posterolateral lobes of head punctate, overlain by oblique and superficial rugulae (Fig. 11D); in lateral view second mesonotal process raised above level of dorsopropodeum. (Nigeria) . . . . . Pheidole semidea
FIGURE 11 A, B) Pheidole dea. Lateral view of minor worker (A), illustrating second mesonotal process at same level as dorsopropodeum, postpetiole relatively small in relation to petiole; full-face view of major worker (B): vertex without cross-meshes and posterolateral lobes longitudinally rugose. C, D) Pheidole semidea. Lateral view of minor worker (C), showing second mesonotal process raised at slightly higher level than dorsopropodeum, postpetiole relatively larger in relation to petiole; full-face view of major worker (D): vertex with cross-meshes and posterolateral lobes obliquely and irregularly rugulose.