Monomorium viridum

Unusually distributed, M. viridum occurs in disjunct eastern US locations.

Identification
DuBois (1986) - A member of the Monomorium minimum species group. Queen Winged; head with rugae; altitrunk with greater than 30 erect to suberect setae projecting above dorsal outline. Male Mandible with four teeth. Worker Mesopleuron punctate; PI 31-36 (34).

Ranges of three other species (Monomorium emarginatum, Monomorium minimum, and Monomorium trageri) overlap the range of M. viridium. These species can be separated by characters found in the keys and diagnoses. Queens of M. viridium possess a notal furrow on the mesonotum while queens of M. minimum and M. trageri do not. Monomorium viridium queens can be separated from M. emarginatum queens since the metanotum of the latter does not project to the level of the propodeum and scutellum. Additionally, head sculpturing is reduced in M. emarginatum queens. Furthermore, both petiole and postpetiole are emarginate in M. viridum queens.

Workers of M. viridum can be separated from M. trageri and M. emarginatum workers since the latter two species have a propodeum with basal face Shorter than declivitous face. Monomorium viridum workers can be separated from those of M. minimum since the former have a punctate mesopleuron.

Distribution
DuBois (1986) - This species occurs in two allopatric populations along the Atlantic coast: one in the Pine Barrens of New Jersey and the other in Georgia and Florida. In spite of intensive collecting by W. L. Brown, Jr., E. O. Wilson, and others, only one collection has been made in the coastal plain between New Jersey and Georgia (North Carolina. Beaufort Co, Wilmar 1.6 km N, W. L. Brown, Jr., & E. O. Wilson). In many areas, this species is replaced by M. minimum. Apparently this difference is due to microhabitat selection for nest sites by queens of both species. Monomorium viridium prefers sand, while M. minimum prefers clay soils (W L. Brown, Jr. pers. comm). In the New Jersey population of M. viridium, collections range from Lakehurst (Ocean Co.) and Island Heights (Ocean Co.) in the north to Cape May (Cape May Co.) in the south. Further north, M. viridum is replaced by M. emerginatum and M. minimum replaces both species to the west. In the Florida population, collections are common throughout the eastern and central portions of the peninsula from Jacksonville (Duval Co.) in the north to Miami (Dade Co.) in the south. The furthest western records for this species appear to be Sarasota (Sarasota Co.) and Gainesville (Alachua Co). This population apparently ranges as far north as Georgia (W. L. Brown, Jr., pers. comm) Monomorium trageri occurs in portions of northern Florida (Tallahassee and Gainesville) while M. minimum occurs to the north and west of the Florida M. viridum population.

This species is often misidentified hence it reported range, based on misidentified specimens, includes many areas where it does not occur. It may occur in more locations than originally stated by DuBios in 1986.

Distribution based on Regional Taxon Lists
Nearctic Region: United States. Neotropical Region: Mexico.

Nomenclature

 *  viridum. Monomorium viridum Brown, 1943: 243 (w.q.) U.S.A. Crozier, 1970: 116 (k.); DuBois, 1986: 98 (m.). Senior synonym of peninsulatum: DuBois, 1986: 96.
 * peninsulatum. Monomorium peninsulatum Gregg, 1945b: 62, pl. 9 (w.q.) U.S.A. Subspecies of viridum: Creighton, 1950a: 223. Junior synonym of viridum: DuBois, 1986: 96.

Type Material
Type series consisting of holotype female and numerous paratype females, males and workers (Brown, 1943) New Jersey. Ocean Co, Lakehurst, August 23, 1940, W. L. Brown, Jr. [Holotype female - Academy of Natural Sciences, Philadelphia, Pennsylvania Number 10561; paratypes in and ]. Synonymous M. peninsulatum type series consisting of “64 females and numerous workers” (Gregg, 1945) Florida: Dade Co, South Miami, E. V. Gregg. [Holotype queen - R. E. Gregg personal collection; paratypes in, , and NMNH].

Worker
Head: (representing different localities; N: 10) HL 0.45-0.58 (0.51), HW 0.39-0.50 (0.44), SL 0.30-0.40 (0.35), EL 0.08-0.13 (0.09), M01) 0.06-0.08 (0.00). Structure—CI 83-89 (85), SIL 53-78 (69), SIW 65-90 (81). Summit of head concave to slightly emarginate. Scape reaching or surpassing occiput by an amount less than length of pedicel. Sculpture—Small to moderate, parallel, longitudinal rugae beginning along lateral margin of clypeus, extending to level of antenna] insertion. Alitrunk. PW 0.24-0.33 (0.27), PL 0.18-0.22 (0.20), WL 0.52-0.66 (0.58). Structure—Anterior propodeal suture deep (almost reaching to level of propodeal suture). Propodeum rounded; declivitous face 1/3 to 1/2 length of basal face. PI 32-36 (34). Pilosity—Dorsal outline of alitrunk with 8-12 erect to suberect setae. Structure—Mesopleuron with dense, small, non-piliferous punctures throughout; anterior propodeal suture with short, large, parallel, longitudinal rugae. Petiole: Subpetiolar process of moderate size. Setae appressed on anterior surface of node, erect on dorsum of nodes, absent elsewhere. Postpetiole. Setae apparessed on anterior surface of node, erect to decumbent on sides, dorsum, and venter (beneath node), absent elsewhere. Color: Head dark brown to brown except as follows: occiput with green tint (most visible in living or recently killed specimens), antenna, mandible, and lateral margin of clypeus brown to yellow-brown. Alitrunk. Dark brown with green tint on dorsum; legs brown to yellow-brown.

Queen
As described for Monomorium minimum except as follows: Head: (representing different localities, N= 8) HL 0.72—0.88 (0.81), HW 0.80-0.95 (0.88), SL 0.58-0.69 (0.63), IOD 0.16-0.22 (0.19), OD 0.10-0.12 (0.11), EL 0.18-0.28 (0.23), MOD 0.14-0.22 (0.18). Structure—Head a little broader than long, Cl 102-113 (107), distinctly longer than scape SIL 73-83 (77); SIW 67-76 (72). Scape reaching or surpassing occiput by an amount less than length of pedicel. Sculpture—Moderate, parallel, longitudinal rugae beginning all along lateral margin of Clypeus, extending behind antennal insertion, and curving towards frontal carina, reaching frontal carina near apex; small, parallel, longitudinal rugae beginning along malar area, extending towards compound eye, paralleling ocular suture and vanishing near level of anterior ocellus; small, parallel, longitudinal rugae beginning near apex of frontal carina and extending to level of anterior ocellus; moderate, parallel, longitudinal rugae beginning near labium and continuing alson gular region ending near occiput. Large piliferous punctures evenly distributed over entire surface of head. Alitrunk. PW 0.60-085 (0.72), PL 0.30-0.50 (0.38), WL 1.55-1.90 (1.70). Structure—Mesonotum with notal furrow. Mesopleural suture straight (small pits on anterior and posterior ends). Propodeum rounded (Basal and declivitous faces of equal length). PI 18-27 (22). Sculpture—Moderate, piliferous punctures on dorsum of scutum, scutellum and mesopleural suture. Propodeum covered with moderate, parallel, longitudinal rugae throughout. Petiole: Dorsum of node flat to slightly emarginate. Setae appressed on anterior surface of node, erect to decumbent on sides, dorsum, and posterior surface of node. Entire surface of petiole covered with small, non-piliferous punctures (obscuring small piliferous punctures where they occur). Lower half of side of petiole (sometimes including lower parts of node) with small, parallel, longitudinal rugae. Posterior surface of node with moderate, transverse, concentric, semicircular rugae. Postpetiole: Dorsum of node flat to slightly emarginate. Setae decumbent to appressed on anterior surface of node, suberect to erect on sides, dorsum, and posterior surface of node. Entire surface covered with large to small non-piliferous punctures. Color: Head dark greenish-brown (green is more pronounced in living or freshly preserved specimens) except as follows: mandibles and antenna dark reddish-brown. Alitrunk and legs reddish-brown with green overlay (green tends to fade in older specimens). Petiole and postpetiole reddish-brown to brown with slight green tint. Gaster black with green or blue hues in some specimens.

Ergatogyne Head: (representing different localities; N: 2) HL 0.66-0.69 (0.68), HW 0.64—0.74 (0.69), SL 0.50 (0.50), IOD 0.14-0.15 (014), OD 0.05 (0.05), EL 0.15 (0.15), MOD 0.09-0.10 (0.10). Structure—Head as broad as long, CI 97-107 (102), distinctly longer than scape, SIL 72-76 (74); SIW 68-78 (73). In full frontal view, head broadest slightly above eyes; side straight; occiput rounded laterally, summit flat to slightly convex. Eye moderate in size (intermediate between queen and worker). Scape reaching or surpassing occiput by an amount less than length of pedicel. Ocelli present. Mandible, maxillary palp, labial palp, clypeal teeth, and frontal carinae as in queen. Pilosity—Setae erect to decumbent over entire surface of head. Antennal pilosity as in queen. Sculpture—Smooth and shining except as follows: trace of small, longitudinal, parallel rugae extending from lateral margin of clypeus and converging near frontal carinae. Moderate piliferous punctures evenly distributed over entire 0.48-0.49 (0.48), PL 0.30-0.31 (0.30), WL 1.11-1.26 (1.18). Structure—Mesonotum with small pit in place of notal furrow. Scuto-scutellar suture on dorsal 1/3 of alitrunk. Remaining description of alitrunk as in queen except that wings are absent (fusion of sclerites indicate the ergatogynes are wingless). Pilosity—As in queen with many erect to suberect setae on sides of propodeum and mesopleuron. Sculpture—Smooth and shining with many piliferous punctures throughout thorax. Sculpture of propodeum as in queen. Petiole: Dorsum evenly convex to flat. Remaining description as in queen. Postpetiole. Dorsum evenly convex to flat. Remaining description as in queen. Gaster. As in queen. Color: As in queen.

Male
Head: (representing 2 localities, N= 5) HL 0.56-0.69 (0.62), HW 0.90-0.95 (0.93), SL 0.28-0.35 (0.31), IOD 0.21-0.26 (0.24), OD 0.14-0.15 (0.15), EL 0.40-0.44 (0.42), MOD 0.25-0.31 (0.28). Structure—CI 138—164 (151), SIL 44-55 (50), SIW 30-37 (33). Mandible with 4 teeth. Pilosity—Setae erect to decumbent over entire head, appressed on gula. Sculpture—Entire head covered with dense, moderate, non-piliferous punctures. Moderate, parallel, rugae beginning along lateral margin of clypeus and converging at antennal insertion; several moderate, parallel, rugae beginning at malar area, continuing to level of compound eye then paralleling ocular suture; clypeus with small to moderate, parallel, longitudinal rugae arising between clypeal teeth and extending to level of antennal insertion; moderate, parallel rugae extending from frontal carinae to level of anterior ocellus. Alitrunk: PW 0.84-0.97 (0.93), PL 0.44-0.52 (0.48), WL 1.68-1.84 (1.76). Structure—Mesonotum with nota] furrow. Scuto-scutellar suture near middle of alitrunk. Mesopleural suture straight. Metanotum not projecting to level of scutellum and propodeum. Propodeum rounded (basal and declivitous faces of equal length. PI 24-29 (28). Sculpture—Moderate piliferous punctures on scutum and scutellum and anterior edge of mesopleuron, small, non-piliferous punctures on propodeum. Petiole: Dorsum of node emarginate. Subpetiolar process of moderate size with anterior edge forming angle. Setae appressed to decumbent on anterior surface of node, subdecumbent to erect on dorsum, sides, and posterior surface of node. All surfaces except dorsum, with small, non-piliferous punctures. Lower 1/3 of side of petiole, below node, longitudinal rugae. Postpetiole. Dorsum of node slightly emarginate. Setae decumbent to erect on all surfaces of node. Dorsum smooth and shining, remaining surfaces covered with small non-piliferous punctures. All surfaces with small piliferous punctures. Genitalia. Eighth sternite with emargination possessing setae; emargination approximately half as deep as wide. Ninth sternite with 18-20 erect setae. Aedeagus with 12 teeth; toothed margin straight. Cuspis of volsella with 7 setae. Color: As in queen. Genitalia yellow brown to brown.