Pseudomyrmex parvulus Ward

Ward, Philip S., 2017, A review of the Pseudomyrmex ferrugineus and Pseudomyrmex goeldii species groups: acacia-ants and relatives (Hymenoptera: Formicidae), Zootaxa 4227 (4), pp. 524-542 : 539-540

Pseudomyrmex parvulus Ward , sp. nov.

( Fig. 8 )

Type material. Holotype worker. BRAZIL Amazonas : Paraná do Xiboreninho, 3°15ʹS, 60°00ʹW [mistranscribed on label as 06°00ʹW], 5 Aug 1979, Canopy Fogging Project, TRS#05, mixed water, Adis, Erwin, Montgomery et al. ( MZSP) (CASENT0794102). Paratypes . 1 worker same data as holotype ( PSWC) (CASENT0762994) ; 1 worker, BRAZIL Amazonas: Rio Tarumã Mirím, 2 km from Rio Negro, 3°02ʹS, 60°17ʹW, 27 Jul 1979, Canopy Fogging Project , TRS#01, black water inundation forest, Adis , Erwin , Montgomery et al. ( USNM) (CASENT0794103).

Other material examined ( UCDC). 1 dealate queen, BOLIVIA Santa Cruz: 35 km SSE Flor de Oro, 450 m (P. S. Ward PSW12198-06).

Worker measurements (n = 3). HL 0.73–0.80, HW 0.56–0.60, MFC 0.005–0.007, LHT 0.40–0.43, CI 0.75– 0.78, REL 0.64–0.65, REL2 0.82–0.86, FCI 0.009–0.012, FI 0.52, PLI 0.63–0.71, PWI 0.52–0.60.

Worker diagnosis. Smaller species (HW 0.56–0.60) with moderately elongate head and eyes (CI 0.75–0.78, REL 0.64–0.65); palp formula 5,3; juncture between dorsal and declivitous faces of propodeum subangulate, and with weak lateral tubercles ( Fig. 8 b); anterodorsal face of petiole ascending rapidly ( Fig. 8 b). Front of head between eyes densely punctulate and sublucid, the punctures separated by about their diameters; head sparsely punctulate and shiny around the ocelli, then more densely punctulate and sublucid at the posterior margin; mesosoma finely coriarious-imbricate and largely opaque; petiole, postpetiole and gaster with very fine dense pubescence, imparting a matte appearance. Standing pilosity very sparse, absent from petiole; a pair of setae present on the pronotal humeri and on the postpetiole (latter pair very short and inconspicuous). Medium yellowish-brown, the pronotum, petiole, postpetiole and appendages lighter.

Comments. In this species the head is densely punctulate between the compound eyes and most of the body has a matte texture. In this respect P. parvulus is similar to P. obtusus , but it is smaller in size (HW 0.56–0.60, with a more elongate head (CI 0.75–0.78) and a pair of setae on the pronotal humeri (absent in P. obtusus ).

Distribution and biology. P. parvulus is known only from two rainforest sites in Amazonas, Brazil (workers from canopy fogging project), and one rainforest location in the Sierra de Huanchaca, Bolivia (dealate queen on low vegetation).

Figures

FIGURES 7 – 8. Pseudomyrmex goeldii group, workers, full-face dorsal view of head (a) and lateral profile of body (b). 7, P. obtusus, Venezuela (CASENT 0794100); 8, P. parvulus, Brazil (CASENT 0762994). Images from AntWeb (www. antweb. org); photographer Matthew Prebus.