Pheidole bessonii, Forel, 1891

Salata, Sebastian & Fisher, Brian L., 2020, The ant genus Pheidole Westwood, 1839 (Hymenoptera: Formicidae) in Madagascar-taxonomic revision of the bessonii species-group, Zootaxa 4843 (1), pp. 1-64: 6-12

publication ID

https://doi.org/10.11646/zootaxa.4843.1.1

publication LSID

lsid:zoobank.org:pub:57044928-1950-4525-850E-E381A52599A1

DOI

http://doi.org/10.5281/zenodo.4488375

persistent identifier

http://treatment.plazi.org/id/03938025-FF8B-A91D-A7D8-B7D2FEA1F98A

treatment provided by

Plazi

scientific name

Pheidole bessonii
status

 

Synopsis of species of the Pheidole bessonii  group

Pheidole antsahabe  sp. nov.

Pheidole atsirakambiaty  sp. nov.

Pheidole bessonii Forel, 1891 

Pheidole clara  sp. nov.

Pheidole decollata Forel, 1892  stat. nov.

Pheidole flammea  sp. nov.

Pheidole flavodepressa  sp. nov.

Pheidole grallatrix Emery, 1899 

Pheidole madecassa Forel, 1892 

Pheidole mantadioflava  sp. nov.

Pheidole maro  sp. nov.

Pheidole oswaldi Forel, 1891 

Pheidole ovalinoda  sp. nov.

Pheidole similis  sp. nov.

Pheidole tenebrovulgaris  sp. nov.

Pheidole uranus  sp. nov.

Pheidole voreios  sp. nov.

Pheidole zirafy  sp. nov.

Taxonomy

The following repetitive characters occurring in the majority of species have been omitted from the individual species accounts. Unless stated otherwise, the following descriptions apply to all species treated here:

Major workers. Dorsal face of head in lateral view not depressed posteriorly; antennal socket shallow; frontal lobe absent; head in full-face view with distinct posteromedian concavity; antenna 12-segmented with 3-segmented club; masticatory margin of mandible with large, stout apical tooth and preapical tooth, followed by long diastema and then short and crenulate tooth just before rounded basal angle; outer surface of mandible mostly smooth and shining, sometimes with weak and sparse puncta; antennal scrobe absent; promesonotum strongly convex, well above level of propodeum; postpetiole shiny and microreticulate, short with slightly convex dorsum, in dorsal view oval with lateromedian dentate projection, pilosity erect; petiole shiny and microrugulate, peduncle with small horizontal lobes on its basal part, node triangular with rounded top, in rear view node dorsoventrally concave, pilosity erect.

Minor workers. Antennal socket shallow, surrounded with few indistinct wrinkles that curve posterolaterally, most often with sculptured interspaces; frontal lobe absent; head in full-face view oval, posterior and anterior of compound eye convex; antenna 12-segmented with 3-segmented club; humeral tubercle not developed into projection; clypeus smooth and shiny; anterior margin regularly convex; promesonotum well above level of propodeum; petiole smooth with ventral face slightly convex, node triangular with few erect setae; postpetiole smooth, convex with few erect setae; gaster smooth and shiny.

Revision of the Pheidole bessonii  group

Diagnosis. Major worker. Postpetiole in profile without conspicuous ventral convexity; antennal socket shallow; frontal lobe absent or indistinct; propodeal spine moderate to large, wide to narrow; head in full-face view sub-rectangular, with lateral margins varying from relatively straight to slightly convex, not or slightly widening posteriorly; head in lateral view sub-oval with distinctly convex dorsal and ventral cephalic margins; occipital lobe never with transverse costulae and usually entirely sculptured (except P. madecassa  , P. maro  and P. uranus  ); frons entirely sculptured, medially costulate to rugocostulate, lateral sides with usually weaker sculpture; antennal scrobe absent or very indistinct; costulae and rugulae on the rest of head thick to very thin; promesonotum short, angular, and moderately low to very low; mesonotal process usually distinct; postpetiole in dorsal view with lateromedian dentate projection; gaster usually at least partially shagreened. Minor worker. Postpetiole in profile without conspicuous ventral convexity; antennal socket shallow; frontal lobe absent or indistinct; propodeal spine minute to moderately large, wide to narrow; promesonotum in lateral view never box-like and posterior mesonotum never steep; promesonotal groove present and distinct (except P. tenebrovulgaris  ); posterior region of head usually elongated, forming short to long neck; nuchal collar present and weakly developed to distinct (except P. madecassa  and P. maro  ); promesonotum moderately low to very low and moderately long to very long, and arched.

Comments. The P. bessonii  group consist of species widely distributed on the island. Six species— P. bessonii  , P. decollata  , P. grallatrix  , P. maro  , P. oswaldi  and P. tenebrovulgaris  can be considered common. The remaining 12 species have more restricted distributions primarily limited to the northern and northeastern parts of the island. The majority of the major and minor workers of the bessonii  group can be easily separated from other taxa based on the combination of the above-mentioned characters. However, majors of P. madecassa  and P. maro  can be confused with major workers of the longispinosa group. They can be separated based on distinctly shorter propodeal spines, denser frons sculpture, and brighter body coloration. Additionally, minors of P. tenebrovulgaris  can be confused with two members of the sikorae  group: P. trichotos Salata & Fisher  and P. veteratrix Forel.  Pheidole tenebrovulgaris  can be separated based on larger body size, longer propodeal spines, higher promesonotum, and dark brown body coloration. There is also one member of the bessonii  group known from Mayotte: P. ragnax  . Because its original description is comprehensive and the species is not recorded from Madagascar, we decided not to include it in our revision. However, we included it in comparative diagnoses within the descriptions of most similar species.

Key to the Pheidole bessonii  group

1 Major worker. Head, in full face view, slightly widening posteriorly and occipital lobe mostly smooth or head not widening posteriorly and occipital lobes with rugae that never arch posterolaterally, body never yellow or orange, head never with short and dense setae ( Fig. 2View FIGURE 2). Minor worker. Posterior part of head not to slightly elongated but never forming a neck, and nuchal collar absent to weakly developed ( Fig. 3View FIGURE 3).................................................................. 2

- Major worker. Head not or slightly widening posteriorly, occipital lobe and sometimes frons with rugae or costulae that arch posterolaterally distinctly to indistinctly. If occipital lobes with rugae then body yellow to orange or brown with lateral sides of head with short, dense setae ( Fig. 6View FIGURE 6). Minor worker. Posterior part of head elongated and often forming a neck, nuchal collar distinct ( Fig. 7View FIGURE 7)....................................................................................... 8 Note. Major worker of P. ovalinoda  and P. flammea  have occipital lobes with distinct rugae and dark body coloration. The best character to distinguish between these taxa is the difference in pilosity on the side of head. Pheidole ovalinoda  has sides of head with short, decumbent to suberect setae while P. flammea  has sides of head with long, suberect to erect setae. If characters match P. ovalinoda  then go to couplet #2; if characters match P. flammea  then go to couplet #8.

2 Major worker. Occipital lobes with thick and moderately dense rugae with mostly smooth interspaces, outer hypostomal tooth absent to weakly developed ( Figs 2EView FIGURE 2, 4GView FIGURE 4). Minor worker. Petiolar peduncle moderately short and thick and node high, postpetiole short and moderately high ( Fig. 5EView FIGURE 5).................................................... Pheidole ovalinoda 

- Major worker. Occipital lobes mostly smooth or with thin and moderately sparse rugae with interspaces most often sculptured, outer hypostomal tooth present and distinct ( Figs 2View FIGURE 2 A–D, F, G, 4E, F). Minor worker. Petiolar peduncle moderately long and thin and node low, postpetiole longer and flat ( Fig. 5View FIGURE 5 A–D, F, G).................................................... 3

3 Major worker. Occipital lobes with thin rugae and indistinctly punctate to smooth interspaces, side of head with moderately dense, short, appressed to subdecumbent pilosity, body dark brown ( Fig. 2FView FIGURE 2). Minor worker. Promesonotal groove absent to indistinct, mesosoma entirely punctate, body dark brown. ( Fig. 5FView FIGURE 5)......................... Pheidole tenebrovulgaris 

- Major worker. Occipital lobes mostly smooth or occipital lobes punctate with sparse and indistinct rugae, sides of head with dense, long, suberect to erect pilosity and body yellowish orange to brown ( Fig. 2View FIGURE 2 A–D, G). Minor worker. Promesonotal groove present and distinct, mesosoma sparsely punctate to smooth, body yellow to yellowish brown ( Fig. 5View FIGURE 5 A–D, G)............ 4

4 Major workers. Occipital lobes never with reduced sculpture or smooth notches ( Fig. 2A, DView FIGURE 2). Minor workers. Posterior part of head slightly elongated, mesosoma mostly punctate ( Figs 3A, D, H, KView FIGURE 3, 5A, DView FIGURE 5)..................................... 5

- Major worker. Occipital lobes entirely or mostly smooth ( Fig. 2B, C, GView FIGURE 2). Minor worker. Posterior part of head never elongated and mesosoma mostly or entirely smooth ( Figs 3B, C, G, I, J, NView FIGURE 3, 5B, C, GView FIGURE 5)....................................... 6

5 Major worker. Promesonotum in lateral view moderately long, angular, and very low ( Fig. 4DView FIGURE 4), inner hypostomal tooth small ( Fig. 27LView FIGURE 27). Minor worker. Occiput slightly elongated, promesonotum moderately long, angular, and very low ( Figs 3D, KView FIGURE 3, 5DView FIGURE 5)................................................................................... Pheidole oswaldi 

- Major worker. Promesonotum in lateral view short, angular, and moderately low ( Fig. 4AView FIGURE 4), inner hypostomal tooth moderately large ( Fig. 27EView FIGURE 27). Minor worker. Occiput not elongated, promesonotum moderately long, angular, and moderately low ( Figs 3A, HView FIGURE 3, 5AView FIGURE 5)................................................................................ Pheidole decollata 

6 Major worker. Lateral frons densely rugose-reticulate, occipital lobes mostly smooth, posteriorly with sparse and weakly developed rugae ( Fig. 2GView FIGURE 2). Minor worker. Occiput slightly elongated; nuchal collar weakly developed ( Fig. 3G, NView FIGURE 3)................................................................................................ Pheidole uranus 

- Major worker. Frons laterally smooth with sparse rugulae, occipital lobes smooth, sometimes with weakly developed rugopuncta ( Fig. 2B, CView FIGURE 2). Minor worker. Occiput not elongated, nuchal collar absent ( Fig. 3B, C, I, JView FIGURE 3)...................... 7

7 Major worker. Antennal scrobe with sparse and very thin rugulae with indistinctly punctate interspaces, mesosoma weakly microreticulate, inner hypostomal tooth large, body reddish brown ( Figs 2CView FIGURE 2, 4C, FView FIGURE 4). Minor worker. Frons and mesosoma with very sparse, weakly developed puncta ( Figs 3CView FIGURE 3, 5CView FIGURE 5).............................................. Pheidole maro 

- Major worker. Antennal scrobe with sparse, very thin rugulae with smooth interspaces, mesosoma smooth with very indistinct and thin rugulae, inner hypostomal tooth small, body yellow to orange ( Figs 2BView FIGURE 2, 4B, EView FIGURE 4). Minor worker. Frons and mesosoma smooth, only anterolateral frons with weakly developed puncta ( Figs 3BView FIGURE 3, 5BView FIGURE 5)..................... Pheidole madecassa 

8 At least minor worker yellow to orange.................................................................... 9

- Minor and major worker bright brown to brownish black..................................................... 13

9 Major worker. Head elongated, posteromedian concavity very deep, CI> 112.0, HL> 1.8 mm ( Fig. 6FView FIGURE 6). Minor worker. Head with moderately long and narrow neck ( Fig. 7F, QView FIGURE 7)........................................ Pheidole flavodepressa 

- Major worker. Head not elongated, posteromedian concavity deep, CI <112.0, HL <1.8 mm ( Fig. 6A, D, H, IView FIGURE 6). Minor worker. Head with short and moderately thick neck ( Fig. 7A, D, H, I, L, O, S, TView FIGURE 7)........................................ 10

10 Major worker. Body brown, costulae on posterior frons arching posterolaterally ( Fig. 6AView FIGURE 6). Minor worker. Promesonotum with weakly developed network of sparse microreticulae ( Fig. 8AView FIGURE 8)................................... Pheidole antsahabe 

- Major worker. Body yellow to orange, costulae on posterior frons never arching posterolaterally ( Fig. 6D, H, IView FIGURE 6). Minor worker. Promesonotum smooth or distinctly punctate ( Fig. 8D, H, IView FIGURE 8).................................................. 11

11 Major worker. Head with lateral sides relatively straight, frons laterally with thick rugocostulae and rugulate interspaces ( Fig. 6IView FIGURE 6). Minor worker. Promesonotum smooth, frons mostly smooth ( Figs 7IView FIGURE 7, 8IView FIGURE 8).......................... Pheidole similis 

- Major worker. Head with lateral sides slightly convex, frons laterally sparsely rugopunctate ( Fig. 6D, HView FIGURE 6). Minor worker. Promesonotum punctate, frons weakly punctate ( Figs 7D, HView FIGURE 7, 8D, HView FIGURE 8)................................................. 12

12 Major worker. Antennal scrobes very indistinct, mostly punctate with additional network of thin and sparse rugae, anterior mesonotum placed slightly higher than pronotum ( Figs 6HView FIGURE 6, 8NView FIGURE 8). Minor worker. Frons with sparse puncta, propodeal spines small with wide base ( Figs 7HView FIGURE 7, 8HView FIGURE 8)......................................................... Pheidole mantadioflava 

- Major worker. Antennal scrobes absent, frons laterally with thick and dense rugae with distinctly punctate interspaces, anterior mesonotum placed lower than pronotum ( Figs 6DView FIGURE 6, 8LView FIGURE 8). Minor worker. Only anterolateral frons with sparse puncta, propodeal spines small and thin ( Figs 7DView FIGURE 7, 8DView FIGURE 8)............................................................ Pheidole clara 

13 Major worker. Occipital lobes with thick, sparse rugae with smooth interspaces, frons laterally with thick, dense rugae with smooth to indistinctly rugulate interspaces ( Fig. 6EView FIGURE 6). Minor worker. Head with short and moderately narrow neck ( Fig. 7E, PView FIGURE 7).................................................................................... Pheidole flammea 

- Major worker. Occipital lobes with very thin, dense rugae, most often with sculptured interspaces, frons laterally with thin, dense rugae with distinctly sculptured interspaces ( Fig. 6B, C, G, J, KView FIGURE 6). Minor worker. Head without a neck or with a long and narrow neck ( Fig. 7B, C, G, J, K, M, N, R, U, VView FIGURE 7)........................................................... 14

14 Major worker. Head elongated, posteromedian concavity very deep, HL> 2.4 mm, CI> 110.0 or head not elongated and posteromedian concavity deep and mesosoma mostly smooth ( Figs 6G, KView FIGURE 6, 8M, OView FIGURE 8). Minor worker. Head with long and narrow neck ( Fig. 7G, K, R, VView FIGURE 7).................................................................................... 15

- Major worker. Head not elongated, posteromedian concavity deep, and mesosoma entirely sculptured, HL <2.4 mm, CI <110.0 ( Figs 6B, C, JView FIGURE 6, 10DView FIGURE 10). Minor worker. Head without neck. ( Fig. 7B, C, J, M, N, UView FIGURE 7).................................. 16

15 Major worker. Head elongated, posteromedian concavity very deep, and mesosoma entirely sculptured ( Figs 6KView FIGURE 6, 8OView FIGURE 8). Minor worker. Neck very long, promesonotal and propodeal dorsum mostly smooth with sparse, transverse rugae, propodeal side and mesopleuron densely rugoreticulate ( Figs 7K, VView FIGURE 7, 8KView FIGURE 8)............................................. Pheidole zirafy 

- Major worker. Head not elongated and posteromedian concavity deep, mesosoma mostly smooth ( Figs 6GView FIGURE 6, 8MView FIGURE 8). Minor worker. Neck long, mesosoma smooth ( Figs 7G, RView FIGURE 7, 8GView FIGURE 8).............................................. Pheidole grallatrix 

16 Major worker. Body black, frons and occipital lobes with moderately thick, moderately dense costulae that arch posterolaterally, interspaces between costulae smooth to indistinctly rugopunctate ( Fig. 6BView FIGURE 6). Minor worker. Body black, frons punctate with few rugae, mesosoma distinctly punctate ( Figs 7BView FIGURE 7, 8BView FIGURE 8).................................... Pheidole atsirakambiaty 

- Major worker. Body brown, at least frons laterally more rugulate, frons and occipital lobes with distinctly punctate to rugopunctate interspaces ( Fig. 6C, JView FIGURE 6). Minor worker. Body yellowish brown to blackish brown, frons usually with strongly reduced sculpture and with smooth notches, mesosoma with smooth notches ( Figs 7C, JView FIGURE 7, 8C, JView FIGURE 8)............................. 17

17 Major worker. Occipital lobes with moderately thin and sparse rugulae that arch posterolaterally, interspaces between rugulae punctate, frons laterally with sparse costulae with distinctly punctate interspaces ( Fig. 6JView FIGURE 6). Minor worker. Occiput elongated, mesosoma microreticulate, promesonotum with sparse microreticulae, promesonotal dorsum mostly to entirely smooth, propodeal spines small and narrow ( Figs 7JView FIGURE 7, 8JView FIGURE 8)..................................................... Pheidole voreios 

- Major worker. Occipital lobes punctate, sometimes with thin and very sparse rugulae that arch posterolaterally, frons laterally with sparser, thinner rugocostulae with distinctly punctate interspaces ( Fig. 6CView FIGURE 6). Minor worker. Occiput not elongated or elongated very slightly, promesonotum mostly smooth, lateral mesosoma sparsely microreticulate, propodeal spines very small with relatively wide base ( Figs 7CView FIGURE 7, 8CView FIGURE 8).......................................................... Pheidole bessonii 

Species accounts

Kingdom

Animalia

Phylum

Arthropoda

Class

Insecta

Order

Hymenoptera

Family

Formicidae

Genus

Pheidole