Genus Liometopum (Dolichoderinae)

• Liometopum Mayr, G. 1861: 38 . Type species: Formica microcephala Panzer, by monotypy.

• OVERVIEW.   This is a Holarctic genus with 8 species worldwide that is also well represented in the fossil record. In the Nearctic region it is found only in the western United States. The Nearctic forms nest in the soil beneath cover or under bark or in crevices in trees, and the nest chambers are usually subdivided by a network of paper like material. Colonies are often populous. Workers forage in files sometimes several hundred feet long and commonly attend coccids and aphids. They are pugnacious and eject a repellent secretion with a strong and disagreeable odor (Smith, D.R. 1797: 1417). They are generalized foragers (Brown, 2000: 56 in Agosti, Majer, et. al. Ants, standard methods for measuring and monitoring biodiversity).
• ZOOGEOGRAPHICAL REGIONS.  Neotropical, Nearctic, Palearctic, Oriental.
• RECOGNITION.   Moderately polymorphic. Psammophore absent. Mandible with about 7 to 9 teeth on the masticatory margin; an indistinct basal angle; 3 to 5 denticles on the basal margin. Head with vertex concave; broadening posteriorly and narrowed anteriorly. Mesonotum and propodeum forming a smooth, continuous profile that may be either flat or convex; metanotum without dorsal impression.
• SIMILAR GENERA.   This genus is easily separated from all other Nearctic dolichoderines by its head shape, profile of mesosoma continuous, and its polymorphism. It is, however, easily confused with the formicine genus Camponotus. Both genera are polymorphic and have a continuous profile of the mesosoma. Camponotus differs by having an acidopore at the tip of the gaster, mandibles with 7 or fewer teeth, head with posterior margin rarely concave. Also, Camponotus lack dentition on the basal margin of the mandible.
• TRIBE.  Dolichoderini.
• REVISIONS.   Wheeler, W.M. 1905h: 321–333.— Shattuck, 1992c: 121–126 (figure - all castes, diagnosis, description, distribution) .
• TAXONOMY.   Smith, M.R. 1943e: 311 (diagnosis of m.) .— Smith, M.R. 1947f: 594, pl. 16, fig. 61 (diagnosis of w., figure (lateral view) of w.) .— Creighton, 1950a: 337–340, pl. 44, figs. 1–4 .— Wheeler, G.C. & Wheeler, J. 1951: 172, 181 (larva) .— Kupyanskaya, 1988: 29–34 (easter Palearctic (in Russian)) .— Shattuck, 1992c: 121–126, figs. 111–117 (description of w.q.m., diagnosis of l., distribution map, figures (full face and lateral views) of w.q.m.) .— Bolton, 1994: figs. 42, 43 (SEMs (full face and lateral view) of w.) .— Shattuck, 1994: 128–130 (catalog) .
• MISCELLANEOUS.   Wheeler, W.M. 1930c: 12–15, fig. 2 (natural history, distribution, relationship to Prenolepis) .

• apiculatum. Liometopum apiculatum Mayr, G. 1870b: 961 (w.) . [Mexico; No types in USA.] Emery, 1895d: 331 (q.) .

• DISTRIBUTION. Western TX, CO, NM, AZ; Mexico (Smith, D.R. 1979: 1417).
• TAXONOMY. Wheeler, W.M. 1905h: 322–324 (description of w.q.m., figure of w., biology) .— Creighton, 1950a: 339, pl. 44, figs. 1–4 (figure (lateral view) w.q.m., wing) .— Shattuck, 1994: 128.
• MISCELLANEOUS. Wheeler, W.M. 1917i: 177–178 (mating flight) .— Gregg, R.E. 1963 .— Gregg, R.E. 1963: 438–441, pl. XXIV (natural history) .— Van Pelt, 1971: 1186 (trophobiosis and feeding habits) .—Ramos-Elorduy de Conconi , Loaeze, Aguilar & Rosas, 1983: 125–130.— Van Pelt, 1983: table 1 (habitat and frequency in the Chisos Mts., Texas) .— MacKay, Lowrie, et. al. 1988: 102 (occurrence in NM) .— Cokendolpher & Francke, 1990: 22 (distribution in TX) .— Ramos-Elorduy & Lévieux, 1992: 21–30 (colony spacing, foraging area) .— Ramos-Elorduy, Lenoir & Lé vieux, 1992: 215–219 (transplanting colonies mixed with L. luctuosum) .
• PHOTOS.

• luctuosum. Liometopum apiculatum subsp. luctuosum Wheeler, W.M. 1905h: 325 (w.) . [USA, CO, El Paso Co.; MCZ.] Forel, 1914c: 619 (m.) . Subspecies of occidentale: Creighton, 1950a: 339. Raised to species: Wheeler, G.C. & Wheeler, J. 1986g: 55; MacKay, Lowrie, et.al. 1988: 102.

• DISTRIBUTION. WY, CO, western TX west to AZ, CA.
• TAXONOMY. Cole, A.C. 1942: 371 .— Creighton, 1950a: 339–340 .
• MISCELLANEOUS. Wheeler, W.M. 1905h: 332.— Mallis, 1941: 75.— Gregg, R.E. 1963: 441–443 (brief natural history) .— Cole, A.C. 1966b: 18 (Nevada Test Site) .— Wheeler, G.C. & Wheeler, J. 1973e: 100–101.—Ramos-Elorduy de Conconi , Loaeze, Aguilar & Rosas, 1983: 125–130.— MacKay, Lowrie, et. al. 1988: 102–103 (occurrence in NM) .— Cokendolpher & Francke, 1990: 22 (distribution in TX) .— Ramos-Elorduy, Lenoir & Lé vieux, 1992: 215–219 (transplanting colonies mixed with L. apiculatum) .— Merickel & Clark, 1994: 148–158 (natural history, occurrence in ID) .— Gulmahamad, 1995: 82–86 (nest architecture, natural history) .

• occidentale. Liometopum microcephalum var. occidentale Emery, 1895d: 330 (w.m..) . [USA, CA, Riverside Co.; No types in USA.] Wheeler, W.M. 1917a: 522 (q.) . Variety of apiculatum: Wheeler, W.M. 1905h: 324. Raised to species: Wheeler, W.M. 1917a: 521.

• DISTRIBUTION. OR, CA; Mexico (Smith, D.R. 1979: 1417).
• TAXONOMY. Wheeler, W.M. 1905h: 324–325 (diagnosis of w.) .— Wheeler, W.M. 1917a: 522 (description q.m.) .— Eckert & Mallis, 1937: 8, 17.— Smith, M.R. 1947f: pl. 16, fig. 61 (figure (lateral view) of w.) .— Creighton, 1950a: 339 .
• MISCELLANEOUS. Mallis, 1941: 75.— Wheeler, G.C. & Wheeler, J. 1973e: 100.— Allred, 1982: 486 (distribution in UT) .— Gulmahamad, 1995: 82–86 (nest architecture, natural history) .
• PHOTOS.