Rasopone mesoamericana, Longino, John T. & Branstetter, Michael G., 2020

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 : 24

Rasopone mesoamericana New Species

( Figs. 5 [male] and 12; Supp Figs. S19–S21 [online only])

(u r n:l s i d:z o o b a n k.o r g:a c t: 1 1 4 0 4 2 2 9 - 0 9 3E - 4F F E -B5 B9- 3750F2572DC2)

HOLOTYPE: 1 worker, Guatemala, Zacapa: 3.5 km SE La Union , 14.95 −89.27 ±?, 1,500 m, 6-vi-1991, cloud forest, forest litter, R. S. Anderson, RSA91-053 [ CAS, unique specimen identifier CASENT0603245 ] . PARATYPES:same data as holotype except 4-vi- 1991, RSA 91-050 [1 worker, MCZC, CASENT0603696 ; 1 worker, UCD, CASENT0603728 ; 1 worker, USNM, CASENT0603690 ; 1 worker, UVGC, CASENT0603565 ] .

Geographic range. Mexico (Chiapas) to Costa Rica.

Diagnosis

Mandible striate; anterior clypeal margin truncate; side of head with variable pilosity, nearly bare to evenly distributed short erect setae; face sculpture of dense, minute puncta overlain with larger, more widely spaced puncta visible in particular orientation and lighting (very faint in some specimens); petiolar node tapering, scale-like.Two species are within geographic and size range of R. mesoamericana :

Rasopone subcubitalis ( Fig. 10 ; Supp Fig. S32 [online only]): petiole less scale-like.

Rasopone JTL037 ( Fig. 12 ; Supp Fig. S39 [online only]): petiole less scale-like.

Measurements, worker: HW 1.47 (1.38–1.59, 8); HL 1.65 (1.53– 1.81, 8); SL 1.23 (1.08–1.33, 6); PTH 1.07 (0.99–1.22, 8); PTL 0.60 (0.55–0.67, 8); CI 89 (86–92, 8); SI 85 (78–88, 6); PTI 56 (53–58, 8).

Measurements, queen: HW 1.40 (1.32–1.48, 2); HL 1.51 (1.44– 1.58, 2); SL 1.15 (1.05–1.25, 2); PTH 1.02 (0.97–1.07, 2); PTL 0.56 (0.56-0.56, 2); CI 93 (92–94, 2); SI 82 (79–85, 2); PTI 55 (53–57, 2).

Biology

This species occurs across a range of wet forest habitats, from 310 to 1,750 m elevation. Most records are from cloud forest, but often at the lower edge, at the transition to lowland habitat. For example, on the Barva transect in Costa Rica, R. mesoamericana is known from an 1,100 m site, while R. costaricensis occurs at 1,500 and 2,000 m sites. BOLD specimens from Guanacaste, Costa Rica are males from Malaise traps at 1,080 m and 1,185 m, and workers from a litter sample and a bait at 1,000 m and 972 m, respectively. In contrast, none are known from the nearby higher elevation peak, where R. costaricensis is common. In some sites workers can be moderately abundant in Winkler samples of forest floor litter and rotten wood. Dealate queens occasionally occur in Winkler samples. Workers are occasionally collected at baits. Males occur in Malaise traps.

Comments

Molecular data indicate that Rasopone mesoamericana and R. subcubitalis are sister species and the two are quite similar. Rasopone mesoamericana has a more asymmetrical, scale-like petiolar node and is larger on average (but the size ranges overlap). The two have no known cases of sympatry in a local assemblage, but the geographic ranges broadly overlap. It may be somewhat arbitrary to treat them as two species at this stage, but they do form two separate clades, and the petiolar shape differences are consistent. BOLD COI sequences are available for many specimens in this clade, and the BOLD results are fully congruent with the UCE results. BOLD sequences segregate into five allopatric BINs, raising the potential for multiple cryptic species.

Figures

Fig. 5. Male of Rasopone mesoamericana sp. nov. (Nicaragua, CASENT0627722). Scale bars are 0.5 mm for face view, 1.0 mm for dorsal and lateral views.

Fig. 10. Distribution map,face view, and lateral view of petiole of Rasopone costaricensis form b (worker,Costa Rica,INB0003223929),R. JTL047 (worker,French Guiana, CASENT0645960), R. panamensis (worker,Costa Rica, CASENT0644252), and R. subcubitalis (holotype worker). On distribution maps,red dots are sites with UCE sequence data. Red boxes are type locality.

Fig. 12. Distribution map, face view, and lateral view of petiole of Rasopone JTL030 (worker, Panama, CASENT0633075), R. JTL037 (worker, Guatemala, CASENT0625283), R. mesoamericana (holotype worker), and R. JTL029 (worker, Panama, CASENT0633053). On distribution maps, red dots are sites with UCE sequence data. Red boxes are type locality.