Monomorium viridis Brown 1943

Seifert, Bernhard, 2025, The Monomorium carbonarium species group in the Nearctic and Europe (Hymenoptera: Formicidae), Soil Organisms (Toronto, Ont.) 97 (1), pp. 55-84 : 76-77

Monomorium viridis Brown 1943

[type investigation]

This species has been described on males, gynes and workers from Lakehurst in New Jersey. Investigated were a paratype winged gyne labelled:” Paratype Monomorium viridum Brown ” [hand-written by Brown], “Lakehurst VIII-25- 40 N. J. W.L. Brown ” and “USNM paratype No 58070” and series of five workers labelled “ Paratype Monomorium viridum Brown ” [hand-written by Brown], “Lakehurst VI-14- 42 N. J. W.L. Brown ”, “USNM paratype No 58070” and “CASENT 0105770 ANTWEB”; both series deposited in NMNH Washington .

Monomorium peninsulatum Gregg 1945

[syn., type investigation]

This taxon has been described from Florida: Dade Co., South Miami based on gynes and workers. Investigat- ed were three paratype winged gynes and nine workers on four pins from NMNH Washington all labelled “So. Miami Fla VII-8-41 EV Gregg” “Crater in sandy soil pine palmetto”, “ Paratype No. 57281 U.S. N.M.” I confirm the synonymy stated by DuBois (1986). The type workers of M. penisulatum as well as another work- er sample from Florida do not show any differences to the material of M. viridum from more northern latitudes. The smaller head size and larger ClSpD of the southern population are within the normal range of intraspecific variation known for the M. carbonarium species group.

All material examined. Numeric phenotypical data were taken in 5 samples with 15 workers and 8 winged gynes. For details see supplementary information SI1, SI2, SI3. All this material originated from the eastern states of the USA

Geographic range. Only known from lowland areas of the eastern states of USA: New York (40.79°N, 74.31°W), New Jersey, North Carolina and Florida (25.76°N, 80.19°W) from sea level up to 23 m.

Diagnosis: --Worker ( Tab. 2, Figs. 16-18 , key). Very small, CS 460 ± 22 µm. Head much shorter than in most species of the group, CL/CW 1.147 ± 0.015. Dents on clypeal margin rather long (ExCly/ CS 5.67 ±0.99%), very acute and widely distant ( Fig. 18 , ClSpD/CS 12.68 ± 0.97%). Frontal car inae more diverging frontad than in most other species (FL/FR 1.077 ± 0.46, FL/CS 0.286 ± 0.007, FR/CS 0.266 ± 0.012). Eye and preocular distance moderately large (EL/CS 0.210 ± 0.007, PrOc/CS 0.240 ±0.009). Scape and funiculus segments very long (SL/CS 0.861 ± 0.014, Fu2/CS 6.86 ± 0.43%, Fu3/CS 5.27 ± 0.24%). Mesosoma moderately long and wide (ML/CS 1.218 ± 0.019, MW/CS 0.582 ± 0.013). Metanotal groove deep, MGr/CS 6.07 ± 0.93%. Dorsal and caudal profile of propodeum not meeting in an angle, as a whole more or less convex. Petiole moderately wide but higher than in most other species (PeW/ CS 0.285 ± 0.012, PeH/CS 0.394 ± 0.011). Postpetiole moderately wide but higher than in other species (PpW/CS 0.356 ± 0.009, PpH/CS 0.315 ± 0.009). Lateral area of mesopleuron dorsad to metanotal groove strongly longitudinally rugulose. Head, mesosoma and gaster dark brown to brown; mandibles antennae and lateral margin of clypeus yellow brown. According to DuBois (1986) the occipital region of head and the dorsum of mesosoma show a green tint in living or freshly dead individuals.

--Gyne ( Tab. 4): The winged gyne should be easily recognized by its low head length index (CL/CW 0.941 ± 0.022) and very large diameter of midocellus (OD/CS 0.133 ± 0.012). A wingless gyne was not available but the data of DuBois (1986) suggest that these have a lower head length index than wingless gynes of other species.

Taxonomic comments. The species is comparably easy to recognize as a combination of the characters underlined above.

Biology. It seems that DuBois (1986) could reliably identify this species and I follow here his statements on live history: The main habitat are open areas with sandy soil. Nest entrances may be marked by craters of ejected sand having a diameter of 12-20 cm. Nest populations are polygynous usually having up to five (rarely up to 60) reproductive gynes. Alates have been observed in July. The morphology of winged gynes indicates a potency for f light-dispersal and independent colony foundation. Wingless gynes were observed in two localities.

Monomorium emarginatum DuBois 1986

Figures

Figure 16. Head of Monomorium viridum in full face view; Florida: Sarasota, 1950

Figure 18. Clypeus of Monomorium viridum in frontodorsal view; Florida: Sarasota, 1950