Pheidole butteli

This species inhabits well-developed forests in lowlands and hill areas. Two colonies each (Eg97-BOR-524, Eg99-BOR-085) included at least two dealate queens. (Eguchi 2001a) Heterick & Kitching (2022) collected this species in a pitfall trap and in the canopy of a lowland dipterocarp forest in Brunei.

Identification
Eguchi (2001a) - This species is recognised among Indo-Malayan congeners by a combination of the following characteristics: hypostoma of the major bearing three median processes; frontal carina of the major inconspicuous; promesonotal dome highly raised in the major; lower part of mesopleuron margined dorsally in the major; head and promesonotum of the minor smooth and shining. P. butteli is separated from the most similar Pheidole tawauensis in which frontal lobe of the major is relatively large and erect, and occipital carina of the minor is stronger.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Borneo, Brunei Darussalam, Indonesia, Malaysia. Oriental Region: Thailand.

Nomenclature

 *  butteli. Pheidole butteli Forel, 1913k: 36 (s.w.q.m.) INDONESIA (Sumatra). See also: Eguchi, 2001a: 6; Eguchi, 2001b: 39.

Worker
Eguchi (2001a) - Major (n=6): TL 2.0-2.4 mm, HL 0.88-1.02 mm, HW 0.76-0.87 mm, SL 0.42-0.48 mm, FL 0.55-0.64 mm, CI 82-88, SI 53-59, FI 70-78. Head broadest about 1/2-2/3 distance of head (as measured from the mid-point of a transverse line spanning the anteriormost and posteriormost projecting points, respectively) (Fig. 9A), in profile not or slightly impressed on vertex (Fig. 9B). Hypostoma bearing three median processes (Fig. 9C). Clypeus without a median longitudinal carina, with anterior margin weakly emarginate medially. Eye situated at about 1/3 distance of head; distance between mandibular insertion and anterior margin of eye 1.4-1.6 times as long as maximal diameter of eye. Frontal carina almost absent, or inconspicuous and extending backward to about 2/3 of head. Antennal scrobe present only around antennal insertion. Antenna with 3-segmented club; scape extending backward to about midlength of head, or slightly beyond there; terminal segment 1.1-1.2 times as long as preceding two segments together. Masticatory margin of mandible with apical and preapical teeth, and a denticle in front of basal angle. Promesonotum forming a high dome, with an inconspicuous prominence on its posterior declivity (Fig. 9D); each dorsolateral portion of the dome weakly produced outward. Mesopleuron sometimes divided by a weak transverse impression into two parts, of which lower part is margined dorsally. Propodeal spine triangular or horn-like, 2-2.5 times as long as diameter of propodeal spiracle. Petiole 1.6-1.8 times as long as postpetiole (excluding he1cium); petiolar node in posterior view hardly or not emarginate at apex. Postpetiole 1.7-1.8 times as broad as petiolar node.

Dorsum of head excluding occipital lobe longitudinally rugose, with smooth and shining interspaces; dorsal and dorsolateral faces of occipital lobe reticulate or rugoso-reticulate, with enclosures smooth and shining or very weakly punctured; lateral face of occipital lobe weakly rugosoreticulate; dorsum of promesonotal dome largely smooth and shining, or very weakly sculptured; anterior and lateral faces of the dome largely smooth and shining; remainder of alitrunk and waist weakly punctured at least partly; first gastral tergite weakly punctured around its articulation with postpetiole. Outer face of mandible sparsely covered with appressed hairs, which are 0.02-0.05 mm in length and shorter than distance between piligerous punctures; submarginal zone of masticatory margin of mandible with a row of longer decumbent hairs. Body brown to reddish-brown, with a little darker gaster; flagella and legs a little lighter than alitrunk.

Minor (n=5): TL 1.4-1.6 mm, HL 0.45-0.50 mm, HW 0.39-0.43 mm, SL 0.43-0.50 mm, AL 0.62-0.69 mm, FL 0.46-0.54 mm, CI 84-89, SI 104-119, FI 114-129. Head in full-face view narrowed behind eye, with almost flat or weakly concave posterior margin (Fig. 9E); occipital carina evanescent dorsally on head. Clypeus without a median longitudinal carina, with anterior margin in full-face view slightly convex medially. Eye situated just in front of midlength of head; distance between mandibular insertion and anterior margin of eye 0.8-0.9 times as long as maximal diameter of eye. Frontal carina and antennal scrobe present only around antennal insertion. Antenna with 3-segmented club; in full-face view scape extending beyond posterior border of head by its 1/5 length; terminal segment ca. 1.1 times as long as preceding two segments together. Promesonotum convex, without any prominence on its posterior declivity (Fig. 9F). Mesopleuron sometimes with a transverse impression. Propodeal spine 1.5-2 times as long as diameter of propodeal spiracle. Petiole ca. 1.8 times as long as postpetiole (excluding helcium); petiolar node in posterior view not emarginate at apex. Postpetiole in dorsal view subhexagonal, 1.4-1.6 times as broad as petiolar node.

Head including clypeus and promesonotum smooth and shining; remainder of alitrunk weakly punctured at least partly; lateral face of petiole weakly punctured; dorsum of petiole, and postpetiole and gaster smooth and shining. Body yellowish-brown (alitrunk sometimes a little lighter than head and gaster); antennae and legs a little lighter than alitrunk.

Type Material
Eguchi (2001b) - major, minor, queen and male; Tandjong Slamat, Sumatra. Six syntypes (3 majors and 3 minors, ) were examined, of which one major is designated as the lectotype.

References based on Global Ant Biodiversity Informatics

 * Chapman, J. W., and Capco, S. R. 1951. Check list of the ants (Hymenoptera: Formicidae) of Asia. Monogr. Inst. Sci. Technol. Manila 1: 1-327
 * Eguchi K. 2001. A revision of the Bornean species of the ant genus Pheidole (Insecta: Hymenoptera: Formicidae: Myrmicinae). Tropics Monograph Series 2: 1-154.
 * Eguchi K. 2001. A taxonomic study on Asian Pheidole (Hymenoptera, Formicidae): new synonymy, rank changes, lectotype designations and redescriptions. Insecta Koreana 18: 1-35.
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 * Eguchi K., and S. Yamane. 2003. Species diversity of ants (Hymenoptera, Formicidae) in a lowland rainforest, northwestern Borneo. New Entomol. 52(1,2): 49-59.
 * [[Media:Forel 1913l.pdf|Forel A. 1913k. Wissenschaftliche Ergebnisse einer Forschungsreise nach Ostindien ausgeführt im Auftrage der Kgl. Preuss. Akademie der Wissenschaften zu Berlin von H. v. Buttel-Reepen. II. Ameisen aus Sumatra, Java, Malacca und Ceylon. Gesammelt von Herrn Prof. Dr. v. Buttel-Reepen in den Jahren 1911-1912. Zoologische Jahrbücher. Abteilung für Systematik, Geographie und Biologie der Tiere 36:1-148.]]
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 * Jaitrong W., and T. Ting-Nga. 2005. Ant fauna of Peninsular Botanical Garden (Khao Chong), Trang Province, Southern Thailand (Hymenoptera: Formicidae). The Thailand Natural History Museum Journal 1(2): 137-147.
 * Jaitrong W.; Nabhitabhata, J. 2005. A list of known ant species of Thailand. The Thailand Natural History Museum Journal 1(1): 9-54.
 * Pfeiffer M., and D. Mezger. 2012. Biodiversity Assessment in Incomplete Inventories: Leaf Litter Ant Communities in Several Types of Bornean Rain Forest. PLoS ONE 7(7): e40729. doi:10.1371/journal.pone.0040754
 * Pfeiffer M., and D. Mezger. 2012. Biodiversity Assessment in Incomplete Inventories: Leaf Litter Ant Communities in Several Types of Bornean Rain Forest. PLoS ONE 7(7): e40729. doi:10.1371/journal.pone.0040986
 * Pfeiffer M.; Mezger, D.; Hosoishi, S.; Bakhtiar, E. Y.; Kohout, R. J. 2011. The Formicidae of Borneo (Insecta: Hymenoptera): a preliminary species list. Asian Myrmecology 4:9-58
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