Genus Odontomachus (Ponerinae)

• Odontomachus Latreille, 1804: 179. Type species: Formica haematoda Linnaeus, by monotypy.
• Pedetes Bernstein, A. 1861: 7. Type species: Pedetes macrorhynchus Bernstein, by monotypy. Synonymy: Dalla Torre, 1893: 51; Brown, W.L. 1976c: 96 .
• Champsomyrmex Emery, 1892f: 558 (footnote) . Type species: Odontomachus coquereli Roger, by monotypy. Subgenus of Odontomachus: Forel, 1917: 238. Revived status as genus: Wheeler, W.M. 1922i: 653. Synonymy: Brown, W.L. 1973b: 179 (Champsomyrmex provisional junior synonym of Odontomachus) ; Brown, W.L. 1976c: 96 (Champsomyrmex junior synonym of Odontomachus) .
• Myrtoteras Matsumura, 1912: 191. Type species: Myrtoteras kuroiwae Matsumura, by monotypy. The type species, Myrtoteras kuroiwae Matsumura, is a junior synonym of Odontomachus monticola Emery. Synonymy: Brown, W.L. 1973b: 182 (Myrtoteras provisional junior synonym of Odontomachus) ; Brown, W.L. 1976c: 96 (Myrtoteras junior synonym of Odontomachus) .

• OVERVIEW.   This tropicopolitan genus has four species that reach the southern portions of the United States. Most colonies are small and are found in soil or in rotting logs and stumps. Workers forage singly and are predaceous and carnivorous. Species of this genus have elongated, linear mandibles and long hairs which arise between the bases of the mandibles and point forward. These hairs act as triggers when the mandibles are open. When the hairs are touched, the mandibles snap shut resulting in a clicking sound. If the mandibles close suddenly on a small object, the object may be cut in two; if they close suddenly on a large object and the mandibles slide over it, the ant is thrown in a series of leaps by the force of its closing mandibles (Smith, D.R. 1979: 1344). Southeastern USA has three species: brunneus, ruginodis, and an undescribed species formerly reported as clarus. The southwest has a single species, clarus, but it is likely there are new species from this region that are yet to be described (M. Deyrup, personal communication). Previously, O. insularis has been reported from the southeast, but this was a result of misidentifications; insularis occurs only in the New World tropics (M. Deyrup, personal communication).
• DISTRIBUTION.   Southern USA.
• ZOOGEOGRAPHICAL REGIONS.  Worldwide except Palearctic region.


      
Photo of Odontomachus ruginodis Smith from FL, Highlands Co.. Courtesy of Ant Web, U. of Calif. Davis


• RECOGNITION.   The genus Odontomachus is among the most distinctive and easily recognized of all ants. Total length 6-20 mm. Mandible long and straight; inserted in the middle of the anterior margin of the head; apex with 2 or 3 teeth arranged in a vertical series. Head widest in the forward third and narrowing both behind and in front of this bulge. The top, backside of the head has a pair of apophyseal lines (dark V-shaped lines) that converge at the top to form a distinct, sometimes shallow groove on the upper part of the front of the head. Scale of petiole always ending in a single acute point dorsally. Gaster usually without a constriction between the first and second segments (this is the only Nearctic genus in subfamily Ponerinae that lacks this constriction).
• SIMILAR GENERA.   The shape of the head and form of the mandibles easily distinguish Odontomachus from all genera other than Anochetus. Members of Anochetus usually have much smaller body size and always lack the pair of apophyseal lines on the backside of the head. Genus Amblyopone has similar mandibles but they lack the vertical series of 2 or 3 teeth at the apex and the mandibles are inserted at the anterolateral corners of the head. Additionally, Amblyopone has its petiole broadly attached to the gaster, and the gaster has a constriction between the first and second segments.
• SPECIES IDENTIFICATION.   Use Deyrup & Cover, 2004. In addition, Deyrup, Trager & Carlin, 1985 may also be useful.
• TRIBE.  Ponerini.
• Literature Overview.   Brown's 1976 revision is the key source for both the taxonomy and natural history of this genus. Wheeler, 1900b is also a good source for natural history.
• REVISIONS.   Smith, M.R. 1939d: 125–130 (USA) .— Brown, W.L. 1976c: 67–171 (World) .
• TAXONOMY.   Smith, M.R. 1943e: 286, 288 (description of male) .— Smith, M.R. 1947f: 538, 541–542 (description and figure of worker) .— Creighton, 1950a: 52–56, pl. 10, fig. 1–5 (figure (lateral view) of w.q.m., wing, full face view of w.) .— Wheeler, G.C. & Wheeler, J. 1952c: 646 (larva) .— Kempf, 1962b: 16–18 (key to Neotropical species) .— Wheeler, G.C. & Wheeler, J. 1964b: 455–456 (larva) .— Wheeler, G.C. & Wheeler, J. 1971b: 1212 (larva) .— Wheeler, G.C. & Wheeler, J. 1976b: 61–62 (revised description of larva) .— Wang, M. 1993a: 219–230 (China (in Chinese)) .— Bolton, 1994: figs. 459, 461 (SEM (full face and lateral view) of w.) .—Shattuck, 1999: 194.—Bolton, 2003: 44, 165, 280.
• MISCELLANEOUS.   Wheeler, W.M. 1900b: 1–31 (natural history) .— Wheeler, W.M. 1922b: 99–103.— Weyer, 1930: 49–55 (leaping habits) .— Eisner, 1957: 475–476 (proventriculus) .— Hölldobler, B. & Wilson, 1990: 190, 192, 222, 246, 264, 280, 281, 320, 247, 353, 380, 393, 394, 431, 546, 561 (worker reproduction, communication, larval feeding) .
• ALL REFERENCES

• brunneus. Atta brunnea Patton, 1894: 618 (w.) . [USA, GA] Deyrup, Trager & Carlin, 1985: 191 (m) . Combination in Odontomachus: Emery, 1895d: 268. Junior synonym of insularis: Emery, 1895d: 268. Revived from synonymy: Brown, W.L. 1976a: 103.
• fuscus. Odontomachus haematodes var. fuscus Stitz, 1925c: 115, fig. 2 (w.) . [Cuba] Unresolved junior primary homonym of O. assiniensis fuscus Stitz, 1916. Synonymy: Brown, W.L. 1976a: 104.

• DISTRIBUTION. Southeastern USA south to Paraguay and Bolivia; W. Indies.
• TAXONOMY. Brown, W.L. 1976c: 77–18, 83, 86, 93, 101, 103, 110, 113, 118–119,130, 135, 137–140, 169–170 (description of w., distribution, natural history) .— Deyrup, Trager & Carlin, 1985: 188–195, fig. 2, 5 (figure (top view of gaster) of w., SEM (full face view) of head of m., timing of nuptual flight of m.) .
• ALL REFERENCES
• PHOTOS.

• clarus. Odontomachus clarus Roger, 1861a: 26 (w.) . [USA, TX; No types in USA.] Patton, 1894: 618 (m.) . Susbpecies of haematodus: Emery, 1911e: 115; Wheeler, W.M. 1914c: 40; Smith, M.R. 1939d: 129. Revived status as species: Taylor, R.W. & Wilson, 1962: 142; Brown, W.L. 1976c: 136.
• texana. Odontomachus texana Buckley, S.B. 1867: 355 (w.) . [USA, TX, (northern)] Junior synonym of insularis: Emery, 1895d: 268. Synonymy: Wheeler, W.M. 1902g: 26.
• coninodis. Odontomachus haematodus subsp. coninodis Wheeler, W.M. 1915b: 391 (w.q.) . [USA, AZ, (Huachuca Mts.)] Synonymy: Brown, W.L. 1976c: 103 .
• desertorum. Odontomachus haematoda subsp. desertorum Wheeler, W.M. 1915b: 391 (w.) . [USA, AZ, Pima Co.] Synonymy: Brown, W.L. 1976c: 103 .
• clarionensis. Odontomachus haematoda subsp. clarionensis Wheeler, W.M. 1934f: 141 (w.) . [Mexico, (Clarion Island)] Synonymy: Taylor, R.W. & Wilson, 1962: 142.

• DISTRIBUTION. LA, TX, AZ; Mexico, Clarion Is., W. Indies.
• TAXONOMY. Wheeler, W.M. 1908h: 407 (description of w.q.m., distribution) .— Smith, M.R. 1947f: pl. 4, fig. 16 (figure (lateral view) of w. (as O. haematoda desertorum)) .— Creighton, 1950a: plate 10 (figure of w.q.m. (as O. haematoda subsp. clarus, O. haematoda coninodis, and O. haematoda desertorum)) .— Taylor, R.W. & Wilson, 1962: 142.— Brown, W.L. 1976c: 77–80, 86, 87, 103, 110, 112, 118, 136, 138 (distribution, biological notes) .— Deyrup, Trager & Carlin, 1985: 191–192, figs. 1, 6 (figure (top view) of w., SEM (full face view) head of m., timing of nuptual flights of m.) .— Rodríguez-Garza, 1997: 236–238 (ergatandromorph, specimen with a mixture of worker and male characteristics, likely a birth defect) .
• MISCELLANEOUS. Wheeler, W.M. 1900b: 1–31 .— Cole, A.C. 1934b: 394 (as O. desertorum) .— Haskins & Enzmann, 1938: 100–143.— Van Pelt, 1983: table 1 (habitat and frequency in the Chisos Mts. Texas) .— Cokendolpher & Francke, 1990: 18–19 (widespread through the southern portion of western TX, habitat, nest sites) .
• ALL REFERENCES

• relictus. Odontomachus relictus Deyrup & Cover, 2004: 137, fig. 1, 2. [USA, FL, Highlands Co.]

• PHOTOS.

• ruginodis. Odontomachus haematodus var. ruginodis Smith, M.R. 1937: 828 (w.q.) . [Bahamas] Deyrup, Trager & Carlin, 1985: 192 (m.) . Raised to species: Wilson, 1964b: 4. Junior synonym of brunneus: Brown, W.L. 1976c: 103. Revived from synonymy: Deyrup, Trager & Carlin, 1985: 192. First available use of the unavailable name Odontomachus haematodes subsp. insularis var. ruginodis Wheeler.
• ruginodis. Odontomachus haematodes subsp. insularis var. ruginodis Wheeler, W.M. 1905c: 82 . Unavailable name. [Bahamas]

• TAXONOMY. Deyrup, Trager & Carlin, 1985: 188–195, fig. 7 (SEM (full face view) head of m.) .
• MISCELLANEOUS. Wheeler, W.M. 1905c: 82 (brief natural history) .— Wheeler, W.M. 1908a: 126 (brief natural history) .— Smith, M.R. 1937: 828 (brief natural history) .
• ALL REFERENCES
• PHOTOS.