Odontomachus malignus Smith, 1859

Sorger, D. M. & Zettel, H., 2011, On the ants (Hymenoptera: Formicidae) of the Philippine Islands: V. The genus Odontomachus Latreille, 1804., Myrmecological News 14, pp. 141-163 : 155-157

Odontomachus malignus Smith, 1859 (Figs. 37-39, 47)

Odontomachus malignus Smith, 1859: 144 (description of worker, type locality: Aru Island, Indonesia). Wilson 1959: 495 (discussion, ecological notes); Brown 1976: 159-160 (discussion, ecological notes, distribution: Tawi- Tawi, Sitanki Jolo Island, Rennell Island); Olsen 2009: 11 (distribution, ecological notes).

Odontomachus tuberculatus Roger, 1861: 28 (syn. Wilson 1959). Odontomachus retrolatior Viehmeyer, 1914: 113 (syn. Brown 1976)

Material from the Philippines examined (17 workers; CSW, CZW, NHMW, USC): (Cebu Prov.): Bantayan: Atop-Atop, N Santa Fe, coast, 18.X.2004, leg. C. V. Pangantihon (P388), 7 ∑∑. Bohol: Loay, Villa Olympia, 25.- 26.VIII.2004, leg. C. V. Pangantihon (P116), 8 ∑∑. Loay, coast with mangroves near mouth of Loboc river, 27.XI. 2005, leg. C. V. Pangantihon (P425b), 2 ∑∑.

Material from other countries examined: 1 worker from Sarawak, Malaysia (NHMW).

Description of worker: Measurements: worker with smallest HW: CI 81, HL 2.25, HW 1.82, MdI 64, MdL 1.43, MsL 3.57, PnW 1.03, PtH 0.87, PtL 0.83, PtW 0.56, SI 128, SL 2.33, TL 10.00; worker with largest HW: CI 82, HL 2.82, HW 2.32, MdI 63, MdL 1.78, MsL 4.57, SI 123, SL 2.85, PnW 1.33, PtH 1.12, PtL 1.12, PtW 0.66, TL 11.13.

Structures: Mandibles long, reaching beyond midpoint of head, similar to O. infandus group. Head roughly rectangular, longer than wide, broadest at level of eyes. Conspicuous tubercles on both sides of median furrow dorso-posteriorly. Eyes located in first third of head. Dorsum of head striate, not reaching nuchal carina. Mesosoma elongate, broadest at level of pronotum. Pronotum rounded, metanotal groove in lateral view present. Very fine longitudinally oriented sculpture on pronotum; metanotum and propodeum with coarse transverse sculpture. Petiole short, truncated; short petiolar spine, anterior and posterior face flat; smooth and shiny, some fine striation may occur laterally. Gaster rounded to oval. Microsculpture on mesosoma and head finely granulate; ant appears matte.

Pilosity: Fine, loose semi-appressed white pubescence on head, mesosoma and petiole; gaster void of pubescence (some isolated hairs may occur), legs and antennae with dense white pubescence. Head with two standing setae, pronotum with some standing setae (2 - 3), setae on gaster increasing in number and length towards apex of abdomen.

Colour: Almost uniformly reddish brown, only head slightly lighter than rest.

Distribution (Philippines: Fig. 47): Widely distributed in the Western Pacific area, with records from Borneo, Philippines, Sulawesi, Palau, New Guinea, New Britain, and Solomon Islands (Wilson 1959, Brown 1976, Olsen 2009). Brown (1976) presents the first records from the Philippines: Tawi-Tawi and Jolo Island in the country's extreme south. Here we present more northern records from the central Philippines, i.e., Bantayan and Bohol.

Habitats: Wilson (1959), Brown (1976), and Olsen (2009) describe the unusual habitat preference of O. malignus in intertidal zones. On Bantayan Island, the second author observed foraging workers in the intertidal zone of coral reef flats during low tide. On Bohol Island, one nest entrance was found in a mangrove close to the open sea.

Notes: This is a unique species, morphologically defined by group characters, and ecologically defined by living in intertidal zones.