Odontomachus alius

Collected in lowland dipterocarp forests, some of the forests remnant patches are strongly degraded.

Identification
Sorger & Zettel (2011) - We characterize workers of O. alius by the following combination of characters: Head distinctly and gaster notably lighter coloured than mesosoma. Head with extended striation (relatively short in specimens from Catanduanes), but never reaching nuchal carina medially. Mesopleuron without smooth area (although striation is faded in some individuals). Petiole with long, S-curved spine.

Odontomachus alius is a variable species with five distinct island-endemic forms from (I) Cebu, (II) Bohol, (III) Leyte and Biliran, (IV) Samar, and (V) Catanduanes. Odontomachus sp. 1 from southern Luzon may also belong to this species, but its characters do not comfortably fit the pattern (see discussion for Odontomachus sp. 1). Each of these forms is relatively stable in its set of characters, and they may as well be treated as subspecies or morphologically weakly differentiated species. There is a distinct trend of changing characters from Cebu eastwards and northwards. The pronotum sculpture changes from transversely striate (Cebu) to roundish or transverse loops (Bohol) to longitudinal loops (other islands). The gaster is lightest (yellowish brown) in specimens from Cebu and Bohol, and darkest in specimens from Samar and Catanduanes. The striation of the temporal prominences is most strongly extended in specimens from Cebu, Bohol, Leyte, and Biliran, intermediate in specimens from Samar, and distinctly reduced in specimens from Catanduanes. This trend contrasts with the parapatric populations of Odontomachus philippinus on Negros with completely smooth temporal prominences and of Odontomachus infandus on southern Luzon with completely striate temporal prominences.

Distribution
Endemic to the Philippines, recorded from the islands of Catanduanes, Samar, Biliran, Leyte, Bohol, and Cebu. (Sorger & Zettel 2011)

Distribution based on Regional Taxon Lists
Indo-Australian Region: Philippines.

Nomenclature

 *  alius. Odontomachus alius Sorger & Zettel, 2011: 152, figs. 5, 11, 17, 46 (w.q.) PHILIPPINES (Cebu I.).

Worker
Measurements: holotype worker: CI 69, HL 3.37, HW 2.32, MdI 60, MdL 2.03, MsL 4.27, PnW 1.38, PtH 1.38, PtL 1.44, PtW 0.53, SI 150, SL 3.48, TL 14.81; paratype worker with smallest HW: CI 68, HL 2.67, HW 1.80, MdI 58, MdL 1.53, MsL 3.47, PnW 1.03, PtH 1.02, PtL 1.11, PtW 0.46, SI 154, SL 2.77, TL 11.75; paratype worker with largest HW: CI 77, HL 3.40, HW 2.62, MdI 64, MdL 2.17, MsL 4.60, PtH 1.46, PtL 1.58, PtW 0.62, PnW 1.50, SI 136, SL 3.55, TL 15.56.

Structures: Head striate, but striation not reaching nuchal carina. Pronotum with variable fine striation, either transversely oriented or with roundish or longitudinal loops. Mesopleuron with fine transverse striation. Petiolar spine S-shaped, very long, acute, slightly bent backwards. Gaster low anteriorly, strongly flattened, impression distinct, often linear.

Pilosity: Pubescence sparse, short.

Colour: Bicoloured; head and gaster light brown to almost yellowish, contrasting with dark brown mesosoma and petiole.

Queen
Measurements: gyne with smallest HW: CI 73, HL 3.43, HW 2.52, MdI 52, MdL 1.80, MsL 4.73, PnW 1.80, PtH 1.53, PtL 1.57, PtW 0.75, SI 131, SL 3.30, TL 16.56; gyne with largest HW: CI 75, HL 3.47, HW 2.62, MdI 56, MdL 1.95, MsL 5.20, PnW 1.95, PtH 1.91, PtL 1.80, PtW 0.77, SI 124, SL 3.25, TL 16.00.

Compared with Odontomachus infandus gyne, striation of head strongly reduced posteriorly. Compared with worker, striation of mesopleuron strongly reduced, in larger gyne absent except for striation in front of meso-metapleural suture, in smaller gyne almost totally absent, except most dorsal area.

Colour: Head, mesonotum, scutellum, metanotum, and mesopleuron pale, yellowish to very light brown, contrasting strongly with other brown body parts. Petiole and gaster light brown, similar to worker.

Type Material
Cebu, west of Cebu City, Minglanilla, Camp 7, 10° 16' N, 123° 45' E. Holotype (worker, USC): Cebu: west of Cebu City, Minglanilla, Camp 7, secondary forest near small creek, 16.XI.2003, leg. H. Zettel & C. V. Pangantihon (358). Paratypes (101 workers, 2 gynes, CSW,, , , ): Cebu: same locality data as holotype, 4 workers. Cebu City, Tabunan, Cantipla-I, forest reserve, ca. 800 m, 23.IX.2006, leg. C. V. Pangantihon (P250), 1 worker, 18.II.2007, leg. H. Zettel (473), 1 worker, 28.IX.2007, leg. C. V. Pangantihon (P270), 2 workers, 8.II.2008, leg. H. Zettel & C. V. Pangantihon (503), 1 worker, 19-20.IX.2008, leg. C. V. Pangantihon (P301), 4 workers, 1 queen, 20-24.VII.2009, leg. C. V. Pangantihon (P327), 2 workers. Dalaguete, Mantalungon, 29-30.VIII.2010, leg. C. V. Pangantihon (P361), 1 worker. Dalaguete, Mantalongon, Dingayup River, 4.XI.2010, leg. H. Zettel & C. V. Pangantihon (524), 5 workers. Bohol: Bilar, Man Made Forest, 29.XI.2005, leg. C. V. Pangantihon (P427), 4 workers. Leyte: Leyte: E Ormoc, Lake Danao area, 11.III.1998, leg. H. Zettel (158), 2 workers, 13.II.2000, leg. S. Schödl (16), 19 workers, 13.II.2000, leg. H. Zettel (237), 3 workers. Baybay, ViSCA/ LSU, Mt. Pangasugan, Calbiga-a River, 50-200 m, 12.II.2000, leg. H. Zettel (236), 13 workers, 20-21.III.2005, leg. H. Zettel & & C. V. Pangantihon (422), 12 workers. Biliran: Almeria, Kabungasan, Mt. Panamao, Upper, 15.XI.2009, leg. C. V. Pangantihon (P334), 1 worker. Samar: Western Samar: east of Basey, Sohoton National Park, banks of Sohoton River, 29.I.2000, leg. S. Schödl (2), 13 workers, leg. H. Zettel (221), 9 workers. Catanduanes: east of San Andres, below Lu Yong cave, 11-12.III.1999, leg. H. Zettel (200), 2 workers, 1 queen, 12.III.1999, leg. F. Seyfert (26), 1 worker, 12.IV.2000, leg. H. Zettel (254), 1 worker.

Etymology
Latin for “the other”, this name refers to the fact that samples of this species were already recognized as “different” by Brown (1976) (but remained unnamed). The name is also inspired by the popular American TV show “Lost”.

References based on Global Ant Biodiversity Informatics

 * Sorger, D.M. and H. Zettel. 2011. On the ants (Hymenoptera: Formicidae) of the Philippine Islands: V. The genus Odontomachus LATREILLE, 1804. Myrmecological News. 14:141-163.