Pseudomyrmex flavicornis (F. Smith 1877)

Ward, Philip S., 1993, Systematic studies on Pseudomyrmex acacia-ants (Hymenoptera: Formicidae: Pseudomyrmecinae), Journal of Hymenoptera Research 2, pp. 117-168: 141-143

publication ID 10.5281/zenodo.10150

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scientific name

Pseudomyrmex flavicornis (F. Smith 1877)


Pseudomyrmex flavicornis (F. Smith 1877) 

(Figs. 16, 25, 63, 69)

Pseudomyrma flavicornis F. Smith 1877:67  . Lectotype worker, Nicaragua ( BMNH) [Examined]  .

Pseudomyrma belti Emery  1890:63. Syntype workers, Alajuela , Costa Rica ( BMNH,  MCSN) [Examined] [Synonymy by Ward 1989:438]  .

Pseudomyrma belti var. obnubila Menozzi 1927a:273  . Syntype worker, San Jose , Costa Rica (H. Schmidt) ( NHMB) [Examined] [Synonymy by Ward 1989:438]  .

Pseudomyrma belti subsp. fellosa Wheeler 1942:160  . Syntype workers, Nicaragua (W. Fluck)  ; Granada , Nicaragua (C. F. Baker) ( AMNH,  LACM,  MCZC) [Examined] [Synonymy by Ward 1989:439]  ,

Pseudomyrmex flavicornis (F. Smith)  ; Kempf 1972:218.

Worker measurements (n = 29). - HL 1.06-1.42, HW 0.99-1.21, MFC 0.075-0.114, Cl 0.83-0.94, REL 0.39-0.45, REL2 0.45-0.51, OOI 1.28-2.71, VI 0.59-0.73, FCI 0.068-0.098, SI 0.40-0.46, SI2 0.82-0.97, NI 0.61-0.68, PLI 0.57-0.67, PWI 0.60- 0.72, PPWI 1.36-1.80.

Worker diagnosis. - Similar to P. ferrugineus  (q.v.) except as follows. Larger, with shorter eyes, on average (Figs. 16,50). Head densely punctulate, opaque; overlying rugulo-punctate sculpture on propodeum tending to be better developed than in P. ferrugineus  . Pilosity and pubescence denser on average. Head black, gaster and postpetiole dark brown to black, mesosoma and petiole varying from black to a contrasting lighter brown or reddish-brown; mandibles, scapes, fronto-clypeal complex, and apices of legs brown.

Comments. - Key traits of this species are the laterally rounded median clypeal lobe, large size (worker HW > 0.98; queen HW 1.12-1.19, n=13), broad opaque head (worker Cl> 0.82; queen Cl 0.73-0.76) and dark color. P. flavicornis  is one of three species in the P. ferrugineus  group whose workers and queens have a black or very dark brown body (mesosoma sometimes contrastingly lighter). The other two, P. mixtecus  and P. veneflcus, are allopatric to P. flavicornis  and smaller in size; other distinguishing features are mentioned in the key and discussed under those species. A tendency towards lighter coloration of the mesosoma in northern populations of P.flavicornis  sometimes makes it difficult to distinguish this species from sympatric dark-colored P. ferrugineus  . Even the darkest workers and queens of the latter species are, however, smaller (an average difference in workers, almost absolute in P. ferrugineus  queens which haveHW 0.96-1.12 (n = 37)) with longer eyes (Fig. 50) and shorter scapes for a given relative head breadth (Fig. 51); and they show some reflectance of light on the upper third of the head between the ocelli and compound eye in contrast to the more or less opaque-headed P. flavicornis  . In addition, P. ferrugineus  queens have more elongate heads (Cl 0.68-0.73) than those of P. flavicornis  .

Distribution and biology. - This is a monogynous species ranging from Guatemala to Costa Rica (Fig. 69), which inhabits Acacia collinsii View Cited Treatment   and, less frequently, A. cornigera View Cited Treatment   and A. hindsii View Cited Treatment   . It was one of the first acacia-ants to be brought to the attention of naturalists, thanks to an early account of its biology by Thomas Belt (1874) (under the name Pseudomyrma bicolor  ). In the more recent literature P. flavicornis  has usually been referred to as " P. belti  ", but note that there is not a perfect correspondence in name usage (Table 1).

Material examined ( AMNH,  ANSP,  BMNH,  CASC,  CUIC,  INBC,  LACM,  MCSN,  MCZC,  MZSP,  NHBM,  NHMV,  PSWC,  SEMC,  UCDC,  USNM)  . -

COSTA RICA Alajuela: Alajuela (A.Alfaro)  ; Atenas (A.Alfaro)  ; Ojo de Agua (A. Alfaro)  ; Tacares (A.Alfaro)  ; Turrücares (A.Alfaro)  ; Guanacaste: 1.4mi N La Cruz , 200m (D.H Janzen)  ; 10.7mi NW Liberia (D.H.Janzen)  ; 1km S Canas (D.H.Janzen)  ; 2mi E Playa Coco (D.H.Janzen)  ; 2mi SE Canas [= 2mi S Canas] (D.H.Janzen)  ; 4km S Canas (D.H.Janzen)  ; 5km S Liberia (D.H.Janzen)  ; 6mi E, 6mi S Canas (D.H.Janzen)  ; 6mi W Liberia (D.H.Janzen)  ; 7km N Canas (D.H.Janzen)  ; Bahia del Coco (A.Alfaro)  ; Ballena, Rio Tempisque (A.Alfaro)  ; El Coco (R.J.Hampton)  ; FincaTaboga, 6mi S, 6mi W Canas (D.H.Janzen)  ; Hda. LaPacifica, 5km NW Canas (E.R.Heithaus)  ; Hda. La Pacifica, nr. Canas , 50m (P.S.Ward)  ; La Cueva, 12km N Liberia (D.H.Janzen)  ; Liberia (A.Alfaro  ; M.G.Naumann)  ; Palo Verde (D.E.Gill  ; H.A.Hespenheide  ; D.H.Janzen  ; D.Whitacre)  ; Palo Verde , 50m (D.M.Olson)  ; Palo Verde , <100m (J.Longino)  ; Rio Corobici, nr.Canas (R.M.Bohart)  ; Santa Cruz (P.P.Calvert)  ; Santa Rosa Natl. Pk. (F.Joyce)  ; Santa Rosa Natl. Pk. , 300m (J.Longino  ; P.S.Ward)  ; Santa Rosa Natl. Pk. , 5m (P.S.Ward)  ; Santa Rosa Natl. Pk. , <5m (P.S.Ward)  ; Tempisque (A.Alfaro)  ; Heredia: Lagunilla (C.H.Ballow)  ; Puntarenas: 1km NE Tarcoles , 20m (P.S.Ward)  ; 4km E Tivives , 5m (L.S.Farley)  ; Barranca,near Puntarenas (A.Alfaro)  ; San Jose: Bebedero (A.Alfaro)  ; Rio Oro (D.H.Janzen)  ; San Jose (Nauck  ; H.Schmidt)  ; Villa Colon (A.Alfaro)  ; Villa Colon , 600-700m (J.Longino)  ; prov.unknown: " Costa Rica "(c.u.)  ; Ciruela (J.F.Tristan)  .

EL SALVADOR Ahuachapan: 7.8mi S Hachadura , 50m (D.H.Janzen)  ; Chalatenango: 5.4mi N La Palma , 850m (D.H. Janzen)  ; La Libertad: 2. 6mi S S anta Tecla , 1010m [=11.8miNLa Libertad] (D.H.Janzen)  ; 2mi E La Libertad (D.H.Janzen)  ; La Libertad (E.S.Ross)  ; Quezaltepeque (D.Cavagnaro & M.E.Irwin)  ; La Union: 7.1 i Amatillo , 190m (D.H.Janzen)  ; Lapaz: 11.6 mi W Zacatecoluca , 0m (D.H.Janzen)  ; San Miguel: 0.4mi W San Miguel (D.H.Janzen)  ; betw. La Union & San Miguel , 110m (D.H.Janzen)  ; San Salvador: San Salvador (O.L.Cartwright  ; N.L.H.Krauss)  ; Sonsonate: 34.4mi W La Libertad (D.H.Janzen)  ; 6.6mi S Sonsonate [=43.6miW La Libertad] (D.H.Janzen)  ; Usulutan: E slope Cerro Verde , 3800ft. (D.Q.Cavagnaro & M.E.Irwin)  ; dept, unknown: Los Chorros (D.Q.Cavagnaro & M.E.Irwin)  ; Los Chorros Natl. Pk. (M.E.Irwin)  .

GUATEMALA Escuintla: 12.6mi NE Escuintla, rd. to Cd. Guatemala , 1120m (D.H.Janzen)  ; 15km E Escuintla [on CA-9] (D.H.Janzen)  ; 43km S Cd. Guatemala [= 15km E Escuintla] (D.H.Janzen)  ; Guatemala: 19km S Cd. Guatemala [on CA-9] (D.H.Janzen)  ; 7.9mi S Cd. Guatemala [on CA-9] (D.H.Janzen)  ; Amatitlan (Bates)  ; Escuintla Cd.Guatemala [= 19km S Cd. Guatemala] (D.H.Janzen)  ; Lake Amatitlan (c.u.)  ; Jutiapa: 47mi S Escuintla, 250m [= 47mi SE Escuintla ] (D.H.Janzen)  ; 7.7mi E Jutiapa, Hwy. 1, 900m (D.H.Janzen)  ; 9.7mi E Jutiapa , 750m ( San Cristobal) [=9.3miNE Jutiapa] (D.H.Janzen)  ; Santa Rosa: 12.2mi W Taxisco (D.H.Janzen)  ; 3.8mi S Guazacapan (D.H.Janzen)  ; Guazacapán (R.H.Painter)  ; Zacapa: 10mi SW El Lobo , 170m [on CA-9] [= 9.2mi NE Piedras de Afilar] (D.H.Janzen)  ; 2.6mi SW Rio Hondo , 200m [on CA-9] (D.H.Janzen)  ; 22.3mi SW Quirigua [on CA- 9] (D.H.Janzen)  ; 22.3mi SW Quirigua [on CA-9] (D.H.Janzen)  ; 8.2mi NE Piedras de Afilar , 160m [on CA-9] [=12.2miNE Rio Hondo] (D.H.Janzen)  ; km 142 on Guatemala-Pto. Barrios Rd. nr. Los Amates (D.H.Janzen)  .

HONDURAS Choluteca: 19mi NE Choluteca (D.H.Janzen)  ; 3.6mi W Choluteca , 200m (D.H.Janzen)  ; 4.5mi W Choluteca (D.H.Janzen)  ; Colon: Puerto Castilla (J.Bequaert)  ; Valle: 4.6mi E Jicaro Galan , 190m (D.H. Janzen)  ; La Union, 28.4mi E El Amatillo (frontera) (D.H.Janzen)  .

NICARAGUA Chontales: no specific locality (T.Belt)  ; Estelí. 2mi N Condega , 500m (D.H.Janzen)  ; Granada: 2.2mi W Nandaime (D.H.Janzen)  ; 2mi N Nandaime , 160m (D.H.Janzen)  ; Granada (C.F.Baker)  ; Leon: 28.1mi SE Leon (D.H.Janzen)  ; Managua: 8.1mi E San Benito (D.H.Janzen)  ; 8.8mi N Tipitapa (D.H.Janzen)  ; 9.9miNEMasachapa,Hwy. 8,180m (D.H.Janzen)  ; 9mi N Tipitapa , 50m (D.H.Janzen)  ; Matagalpa: 15.8mi NW Sebaco [= 15.8mi W Sebaco] (D.H.Janzen)  ; 2.6miN Dario (D.H.Janzen)  ; 4.1mi S Matagalpa , 650m (D.H.Janzen)  ; 4.5mi SE Dario (D.H.Janzen)  ; Rivas: 1mi N San Juan del Sur (D.H.Janzen)  ; 1 mi NW Penas Blancas [==mi N Penas Blancas] (D.H.Janzen)  ; 20.5mi NW Penas Blancas (D.H.Janzen)  ; 4.4miSELaVirgen [= 4.4mi SLaVirgen] (D.H.Janzen)  ; IslaOmetepe (F. Joyce)  ; La Virgen [on Hwy.1] (D.H.Janzen)  ; San Juan del Sur , 10m (D.H.Janzen)  ; Zelaya: Wounta Hanlover (Fluck)  ; dept.unknown: “Nicaragua” (W.Fluck  ; c.u.)  .


United Kingdom, London, The Natural History Museum [formerly British Museum (Natural History)]


Italy, Genova, Museo Civico di Storia Naturale "Giacomo Doria"


Switzerland, Basel, Naturhistorisches Museum


USA, New York, New York, American Museum of Natural History


USA, California, Los Angeles, Los Angeles County Museum of Natural History


USA, Massachusetts, Cambridge, Harvard University, Museum of Comparative Zoology


USA, Pennsylvania, Philadelphia, Academy of Natural Sciences


USA, California, San Francisco, California Academy of Sciences


USA, New York, Ithaca, Cornell University


Costa Rica, Santo Domingo de Heredia, Instituto Nacional de Biodiversidad (INBio)


Brazil, Sao Paulo, Sao Paulo, Museu de Zoologia da Universidade de Sao Paulo








USA, Kansas, Lawrence, University of Kansas, Snow Entomological Museum


USA, California, Davis, University of California, R.M. Bohart Museum of Entomology


USA, Washington D.C., National Museum of Natural History, [formerly, United States National Museum]














Pseudomyrmex flavicornis (F. Smith 1877)

Ward, Philip S. 1993

subsp. fellosa

Wheeler 1942: 160

var. obnubila

Menozzi 1927: 273

Pseudomyrma belti

Emery 1890

Pseudomyrma flavicornis

F. Smith 1877: 67