Pheidole planidorsum

Nothing is known about the biology of .

Identification
Eguchi (2001) - This species, together with Pheidole merimbun, has a combination of the characteristics noted under P. merimbun, but occipital lobe is smooth and shining in the major of the latter. This species is also similar to Pheidole bugi, but head above subocular level and alitrunk are distinctly punctured in the minor of the latter.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Borneo, Indonesia, Malaysia, Philippines. Oriental Region: Vietnam.

Nomenclature

 *  planidorsum. Pheidole planidorsum Eguchi, 2001b: 91, fig. 35 (s.w.q.) BORNEO.

Worker
Major (n=6): TL 2.3 mm, HL 0.85-0.86 mm, HW 0.76 mm, SL 0.40 mm, FL 0.53-0.55 mm, CI 88-90, SI 52-53, FI 70-73. Head broadest at about 3/5 distance of head (as measured from the mid-point of a transverse line spanning the anteriormost and posteriormost projecting points, respectively) (Fig. 35A), in profile slightly impressed on vertex (Fig. 35B). Hypostoma bearing three median processes (medianmost one poorly developed) (Fig. 35C). Clypeus without a median longitudinal carina, with anterior margin very weakly concave medially. Eye situated just behind 1/3 distance of head; distance between mandibular insertion and anterior margin of eye 1.4-1.5 times as long as maximal diameter of eye. Frontal carina weak, extending backward to about 2/3 distance of head. Antennal scrobe inconspicuous, running along frontal carina. Antenna with 3-segmented club; scape extending backward to 3/5 distance of head; terminal segment ca. 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, without a distinct prominence on its posterior declivity (Fig. 35D); each dorsolateral portion of the dome produced outward. Mesopleuron with a weak transverse impression. Propodeal spine elongatetriangular, 2-2.5 times as long as diameter of propodeal spiracle. Petiole 1.6-1.7 times as long as postpetiole (excluding helcium); petiolar node in posterior view weakly emarginate at apex. Postpetiole ca. 1.5 times as broad as petiolar node.

Frons and gena longitudinally rugose; dorsal and dorsolateral faces of occipital lobe reticulate; dorsum of promesonotal dome smooth and shining with several transverse rugulae; lateral face of promesonotal dome smooth and shining; upper part of mesopleuron and lateral face of propodeum punctured weakly and dull; lower part of mesopleuron sometimes partly smooth and shining; lateral faces of petiolar pedicel and postpetiole very weakly punctured; dorsa of petiole and postpetiole, and gaster smooth and shining. Outer face of mandible sparsely covered with appressed to decumbent hairs, which are 0.02-0.04 mm in length and shorter than distance between piligerous punctures. Body yellowish-brown; flagella and tarsi light yellowish-brown.

Minor (n=5): TL 1.3-1.4 mm, HL 0.44-0.45 mm, HW 0.40-0.41 mm, SL 0.38 mm, AL 0.56-0.58 mm, FL 0.38-0.40 mm, CI 89-92, SI 92-95, FI 95-98. Head in full-face view almost flat posteriorly (Fig. 35E); occipital carina almost absent 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 almost as long as maximal diameter of eye. Frontal carina rarely present as an inconspicuous rugula extending behind eye. Antennal scrobe present only around antennal insertion. Antenna with 3-segmented club; in full-face view scape slightly extending beyond posterior border of head; terminal segment 1.1-1.2 times as long as preceding two segments together. Promesonotal dome low and relatively flat dorsally (Fig. 35F), very weakly margined dorsolateraUy, without any prominence on its posterior declivity. Mesopleuron without a distinct transverse impression. Propodeal spine almost twice as long as diameter of propodeal spiracle. Petiole ca. 1.7 times as long as postpetiole (excluding helcium). Postpetiole ca. 1.5 times as broad as petiolar node.

Clypeus smooth and shining; remainder of dorsum of head above subocular level slightly and coarsely rugose and weakly shining; promesonotum largely smooth and shining; remainder of alitrunk punctured; lateral face of petiolar pedicel weakly punctured; dorsum of petiole, and postpetiole and gaster smooth and shining. Body light yellowish-brown; legs lighter than alitrunk.

Type Material
Holotype Major, colony: Eg96-BOR-090, near Kota Kinabalu, Sabah, E. Malaysia, K. Eguchi leg., 1996, deposited in. Paratypes 2 majors, 34 minors and 1 queen from the same colony with the holotype, deposited in and UMS.

References based on Global Ant Biodiversity Informatics

 * 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., S. Yamane, and S.Y. Zho. 2007. Taxonomic revision of the Pheidole rinae Emery complex. Sociobiology 50 (1): 275-284.
 * Eguchi K.; Bui T. V.; Yamane S. 2011. Generic synopsis of the Formicidae of Vietnam (Insecta: Hymenoptera), part I  Myrmicinae and Pseudomyrmecinae. Zootaxa 2878: 1-61.
 * Pfeiffer M., D. Mezger, and J. Dyckmans. 2013. Trophic ecology of tropical leaf litter ants (Hymenoptera: Formicidae) - a stable isotope study in four types of Bornean rain forest. Myrmecological News 19: 31-41.
 * 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