Rasopone minuta (MacKay and MacKay)

Longino, John T. & Branstetter, Michael G., 2020, Phylogenomic Species Delimitation, Taxonomy, and ‘ Bird Guide’ Identification for the Neotropical Ant Genus Rasopone (Hymenoptera: Formicidae), Insect Systematics and Diversity 4 (2), No. 1, pp. 1-33 : 25

Rasopone minuta (MacKay and MacKay)

( Fig. 6 ; Supp Figs. S22 and S23 [online only])

Pachycondyla minuta MacKay and MacKay, 2010: 463 , figs. 181, 585.

Holotype queen: Mexico, Chiapas, 10 km W Palenque [label indicates 10 km S], 30 May 1988 (W. Mackay #10600) [ MCZC, examined].

Rasopone minuta: Schmidt and Shattuck, 2014: 210 .

Geographic range. Mexico (Chiapas) to Honduras.

Diagnosis

Lowland; mandible smooth and shiny; anterior clypeal margin truncate; side of head bare or with a few inconspicuous erect setae; petiolar node moderately tapering, scale-like; color orange. The most similar species is R. pluviselva ( Fig. 6 ; Supp Figs. S26 and S27 [online only]), which has shorter scapes on average (mean SI 73 vs 77).

Measurements, worker: HW 0.88 (0.83–0.93, 7); HL 1.01 (0.95– 1.08, 7); SL 0.68 (0.64–0.72, 7); PTH 0.59 (0.58–0.61, 7); PTL 0.34 (0.31–0.37, 7); CI 87 (85–90, 7); SI 77 (76–80, 7); PTI 57 (52–60, 7).

Measurements, queen: HW 0.88 (0.85–0.90, 2); HL 1.02 (0.99– 1.05, 2); SL 0.66 (0.63–0.69, 2); PTH 0.59 (0.58–0.60, 2); PTL 0.36 (0.34–0.39, 2); CI 86 (86-86, 2); SI 76 (75–76, 2); PTI 61 (58–64, 2).

Biology

This species occurs in lowland wet to seasonal moist forest, with records from sea level to 890 m elevation. The holotype queen was collected in a pitfall trap. Other specimens are from Winkler samples of forest floor litter and rotten wood. A dealate queen was collected in a Winkler sample.

Comments

This is one of the two smallest species, the other being the allopatric R. pluviselva , which occurs further south. These two species are very similar but differ in relative scape length: R. minuta , SI 76–80 (n = 7); R. pluviselva , SI 72–74 (n = 7). Rasopone minuta is a lowland species, typically without sympatric forms at low elevation, but overlapping with cloud forest species (such as R. subcubitalis ) at the upper end of its elevational range. UCE and COI data support the delimitation of this species.

MacKay and MacKay included in the description a worker from Guatemala, but expressed doubts of its conspecificity.They indicated that the worker petiolar node was rectangular, rather than narrowed dorsally as in the holotype queen. Petiole shape shows little intraspecific variation, and the worker is undoubtedly not conspecific. They also identified a worker from Venezuela as R. minuta , but this is also unlikely to be conspecific.

Figures

Fig. 6. Distribution map, face view, and lateral view of petiole of Rasopone pluviselva (holotype worker), R. minuta (worker, Mexico, Chiapas,CASENT0609834), R. JTL043 (worker, Ecuador, MCZ-ENT00716620), and R. JTL048 (worker, French Guiana, CASENT0645961). On distribution maps, red dots are sites with UCE sequence data. Red boxes are type locality.