Odontomachus malignus

A coastal species with an affinity for the intertidal zone.

Identification
Sorger & Zettel (2011) - This is a unique species, morphologically defined by group characters, and ecologically defined by living in intertidal zones.

Distribution
Sorger & Zettel (2011) - 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.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Borneo, Indonesia, Malaysia, New Guinea, Philippines, Solomon Islands.

Biology
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. (Sorger & Zettel 2011)

Nomenclature

 *  malignus. Odontomachus malignus Smith, F. 1859a: 144 (w.) NEW GUINEA. Senior synonym of retrolatior: Brown, 1976a: 104; of tuberculatus: Emery, 1887b: 429; Wilson, 1959a: 495. See also: Brown, 1976a: 159; Sorger & Zettel, 2011: 155.
 * tuberculatus. Odontomachus tuberculatus Roger, 1861a: 28 (w.) ASIA (no locality given). Subspecies of malignus: Mann, 1919: 305. Junior synonym of malignus: Emery, 1887b: 429; Emery, 1911d: 113; Wilson, 1959a: 495.
 * retrolatior. Odontomachus retrolatior Viehmeyer, 1914a: 113 (w.) NEW GUINEA. Junior synonym of malignus: Brown, 1976a: 104.

Worker
Sorger & Zettel (2011) - 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.

Smith Types


Odontomachus malignus

Holotype worker in. Labelled “Aru 55,” and bearing a Donisthorpe type-label. Two other workers, similarly mounted, are in ; one is from “M” (= Mysol I.), the other is from “Mat” (= Martabello I.).