Pseudomyrmex mixtecus Ward

Ward, Philip S., 1993, Systematic studies on Pseudomyrmex acacia-ants (Hymenoptera: Formicidae: Pseudomyrmecinae), Journal of Hymenoptera Research 2, pp. 117-168: 144

publication ID 10.5281/zenodo.10150

publication LSID


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scientific name

Pseudomyrmex mixtecus Ward

sp. nov.

Pseudomyrmex mixtecus Ward  , sp. nov.

(Figs. 15, 26, 55, 61, 69)

Holotype worker. - MEXICO, Guerrero: 25.4 mi. S. Chilpancingo , 10. viii. 1966, D. H. Janzen #M008810966 ( LACM). HW 0.97, HL 1.07, EL 0.48, PL 0.55, PH 0.35  .

Paratypes. - Same data as holotype, and three other accession numbers ( M007810966, M009810966, M010810966) with same locality, date, and collector: series of 43 workers, 34 queens and 17 males (  AMNH,  BMNH,  CASC,  EBCC,  GBFM,  INBC,  LACM,  MCZC,  MZSP,  PSWC,  UCDC,  USNM). Additional non-type material is listed below  .

Worker measurements (n - 13). - HLO.94-1.19, HW 0.89-1.03, MFC 0.054-0.073, Cl 0.86-0.95, REL 0.42-0.47, REL2 0.46-0.52 OOI1.22-2.28, VI 0.61-0.73, FCI0.056-0.073, SI0.43-0.45, SI2 0.86- 0.97, NI 0.60-0.65, PLI 0.60-0.68, PWI 0.60-0.68, PPWI 1.40-1.73.

Worker diagnosis. - Similar to P. ferrugineus  (q.v.) except as follows. Size smaller ( HW <1.04, LHT <0.90), head broad (Cl> 0.85); frontal carinae separated by about basal scape width or less ( FCI 2 0.45-0.54). Basal and declivitous faces of propodeum forming a less obtuse angle in profile than typical for P. ferrugineus  (compare Figs. 26 and 27). Head densely punctulate, opaque. Standing pilosity rather common, usually some setae exceeding 0.12 mm and 0.20 mm in length on mesosoma dorsum and petiole, respectively. Pubescence dense but appressed. Very dark brown to black, appendages lighter.

Comments. - P. mixtecus  is distinguished from all other species, except P. veneficus  and P. flavicomis  , by its laterally rounded median clypeal lobe, broad head, and black (or very dark brown) body. It differs from P. veneficus  by the fully opaque head, absence of conspicuous suberect pubescence on the petiole, and larger size. P. mixtecus  is evidently closely related to P. flavicomis  but averages smaller in size (compare worker HW and LHT values), a difference which is absolute in queens (queenHW 0.96-1.01 (n=8), whereas queen HW> 1.11 in P. flavicomis  ). In addition the petiole is relatively longer and higher, for a given head width, in both workers and queens of P. mixtecus  (Figs. 44-47).

Distribution and biology. - P. mixtecus  is known only from the Mexican states of Guerrero and Oaxaca (Fig. 69). Colonies have been collected from Acacia hindsii View Cited Treatment   and A. collinsii, View Cited Treatment   but little more has been recorded about their biology. Janzen’s field notes indicate that this species is monogynous.

Material examined. Type material listed above, plus the following ( CUIC,  LACM,  MCZC,  MZSP,  PSWC,  SEMC,  USNM,  WPMC  ). -

MEXICO Gro.: 10mi NE Acapulco (D.H.Janzen)  ; 29.6mi N Acapulco , 1400ft. (D.H.Janzen)  ; 30mi N Acapulco, Hwy.95 (Cornell Univ. Mex. Field Party)  ; 57.8mi S Chilpancingo, Hwy.95 (D.H.Janzen)  ; 74km N Acapulco (W.MacKay)  ; Acapulco (Baker  ; F.Knab  ; N.L.H.Krauss  ; L.J.Lipovsky)  ; Puerto Marques (N.L.H.Krauss)  ; San Geronimo de Juarez (W.von Hagen)  ; Oax.: 11.4-17.0mi W Tehuantepec (D.H.Janzen)  ; 13.8mi W Tehuantepec , 1500ft. (D.H.Janzen)  ; 19km N San Pedro Pochutla , 200m (W.MacKay)  ; 6.0mi E Niltepec, Hwy. 190, 100m (D.H.Janzen)  .


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


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


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


USA, California, San Francisco, California Academy of Sciences


Mexico, Jalisco, San Patricio, Universidad Nacional Autonoma de Mexico, Estacion de Biologia "Chamela"


Panama, Panama, Universidad de Panama


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


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


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




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]


USA, New York, Ithaca, Cornell University


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