Pseudomyrmex nigrocinctus ( Emery 1890 )

Ward, Philip S., 1993, Systematic studies on Pseudomyrmex acacia-ants (Hymenoptera: Formicidae: Pseudomyrmecinae), Journal of Hymenoptera Research 2, pp. 117-168 : 143-146

Pseudomyrmex nigrocinctus ( Emery 1890)

(Figs. 13, 22, 56, 72)

Pseudomyrma nigrocincta Emery 1890: 64 . Syntype workers, queens, males, Alajuela , Costa Rica (A. Alfaro) ( BMNH, MCSN, MCZC, MHNG) [Examined]. One syntype worker from MCSN here designated LECTOTYPE .

Pseudomyrma alfari Forel 1906: 228 . Twosyntype workers, Tivives, embouchure de Jesus-Maria , Costa Rica (A. Alfaro) ( MHNG) [Examined]. One syntype here designated LECTOTYPE. Syn. nov.

Pseudomyrma nigrocinta var. bicincta Santschi 1922: 347 . Syntype workers, Costa Rica ( MHNG, NHMB) [Examined]. One syntype from NHMB here designated LECTOTYPE. Syn. nov.

Pseudomyrma peltata Menozzi 1927a:273 . Three syntype workers, SanJose , Costa Rica (H. Schmidt) ( NHMB) [Examined], Syn. nov. Pseudomyrmex nigrocincta [sic] (Emery); Janzen 1966:252 .

Pseudomyrmex nigrocinctus (Emery) ; Kempf, 1972:221.

Worker measurements (n = 21). - HL 0.89-1.08, HW 0.74-0.85, MFC 0.035-0.051, Cl 0.75-0.84, REL 0.40-0.45, REL2 0.51-0.56, OOI 1.39-2.76, VI 0.62-0.78, FCI 0.044-0.065, SI 0.44-0.48, SI2 0.81-0.89, NI 0.58-0.64, PLI 0.59-0.68, PWI 0.49- 0.61, PPWI 1.10-1.30.

Worker diagnosis. - Small species with elongate head and short eyes (REL ≤ 0.45, REL ≤ 2 0.56, EL / LHT ≤ 0.61). Palp formula 5,3. Median clypeal lobe rather narrow, its surface and anterior margin convex. Frontal carinae separated by about basal scape width (FCI ≈ 0.055). Metanotal groove well marked; basal and declivitous faces of propodeum subequal (Fig. 22). Petiole short (PLI> 0.57), its anterior peduncle broad in dorsal view (PWI 3 0.50 - 0.61) and not well differentiated from the node (Fig. 22). Petiole lacking expanded posterolateral comers. Postpetiole less broad than in most other species in the P. ferrugineus group (see PPWI values). Head densely punctulate and subopaque, becoming sublucid posteriorly where the punctulae are separated by shiny interspaces. Mesosoma punctulate to (laterally) coriarious-imbricate, sublucid, becoming subopaque on the propodeum. Standing pilosity moderately common (as in Fig. 22); pubescence dense and closely appressed. Orange-brown, often with anterolateral fuscous patches on abdominal tergite IV (these form a distinct transverse black band in queens).

Comments. - Workers and queens of P. nigrocinctus are easily distinguished from all other acacia ants, except P. particeps (see below), by their small size (HW <0.86 in both castes), elongate head in the worker (worker Cl <0.85), and narrow petiole and postpetiole (worker PWI 3 ≥ 0.50, worker PPWI ≤ 1.30, queen PWI 2 0.57 - 0.63). The orange color and short eyes are also characteristic.

Distribution and biology. - P. nigrocinctus is found from Guatemala to Costa Rica, with most records coming from the southern end of its range (Fig. 72). Colonies are monogynous, and have been collected from Acacia collinsii , A. cornigera and A. hindsii . Records from Acacia gentlei and A. globulifera ( Beulig & Janzen 1969: 59) need to be confirmed because of possible confusion with P. peperi . Janzen’s (1967 b) observations on " P. nigrocincta " in Mexico refer to P. peperi . On the other hand descriptions of the biology and behavior of P. nigrocinctus in Costa Rica ( Janzen 1973, 1974, 1975, 1983; Beulig & Janzen 1969) are reliably attributed to P. nigrocinctus .

Material examined ( AMNH, ANSP, INBC, LACM, MCSN, MCZC, MHNG, MZSP, NHMB, PSWC, USNM, WPMC) . -

COSTA RICA Alajuela: Alajuela (A.Alfaro) ; Atenas (A.Alfaro) ; Cascajal (A.Alfaro) ; Escobal (A.Alfaro) ; Ojo de Agua (A.Alfaro) ; Turrucares (P.P.Calvert) ; Guanacaste: 1.4mi N La Cruz (D.H.Janzen) ; 10.7mi NW Liberia (D.H.Janzen) ; 10mi NW Liberia , 70m (D.H.Janzen) ; 10mi NW Liberia , 70m [= 10.7mi NW Liberia] (D.H.Janzen) ; 2mi S Canas (D.H.Janzen) ; 4km N Canas (D.H.Janzen) ; 5km S Liberia (D.H.Janzen) ; 7km N Canas (D.H.Janzen) ; El Coco (R.J.Hampton) ; Finca Taboga, 6mi S, 6mi W Canas (D.H.Janzen) ; Garita (A.Alfaro) ; Hda. La Pacifica, nr. Canas , 50m (P.S.Ward) ; La Cueva, 12km N Liberia (D.H.Janzen) ; Palo Verde (D.E.Gill ; D.H.Janzen) ; Palo Verde , 50m (D.M.Olson) ; Santa Cruz (P.P.Calvert) ; Santa Rosa Natl. Pk. , 290m (P.S.Ward) ; 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) ; Puntarenas: 2km E Tivives , <5m (L.S.Farley) ; Tivives (A.Alfaro) ; San Jose: 3.5km NE Santiago de Pur (D.H.Janzen) ; San Jose (H.Schmidt ; c.u.) ; prov.unknown: " Costa Rica " (c.u.) .

GUATEMALA Zacapa: 2.0mi NE Rio Hondo , 190m [on CA-9] (D.HJanzen) ; 22.3mi SW Quirigua [on CA-9] (D.H.Janzen) .

HONDURAS Choluteca: 7.4miNECholuteca , 150m (D.H.Janzen) .

NICARAGUA Boaco: 11.7mi E San Benito (D.HJanzen) ; Esteli: 13.1mi N San Isidro (D.H.Janzen) ; 2.5mi N Condega , 620m (D.H.Janzen) ; 6.8mi N San Isidro , 780m (D.H.Janzen) ; 7.5mi NW San Isidro , 550m (D.H.Janzen) ; Leon: Izapa (J.M.Maes) ; Madriz: 3mi W Somoto , 650m (D.HJanzen) ; Matagalpa: 15.8mi NW Sebaco (D.H.Janzen) ; 2.6mi N Dario (D.H.Janzen) ; 4.5mi SE Dario (D.H.Janzen) ; 4mi S Dario , 350m (D.H.Janzen) ; Rivas: 1km W Penas Blancas (D.H.Janzen) ; C.R. border, 1mi N Penas Blancas , <5m [=1mi NW Penas Blancas] (D.H.Janzen) ; Isla Ometepe (F.Joyce) .