Turneria dahlii

Specimens of this species have been found on trees in rainforests, with one collection from Hydnophytum. Wilson (1962) found this species, together with T. pacifica, to be one of the dominant arboreal ants on Espiritu Santo. Collection sites occur between 0 and 1000 meters, with most below 100 meters.

Identification
Eye width < 0.16, occiput-ocular distance > 0.18, relative eye length (eye length/head width) < 0.42, frontal lobes with 1 or 2 erect hairs, lateral areas of head weakly imbricate and with integument shiny, area between propodeal protuberances flat to slightly convex, color uniform yellowish brown to dark brown color.

The clypeus possesses between 12 and 18 erect hairs. Separation from T. pacifica is based on the difference in color: uniform in T. dahli and bicolored in T. pacifica. In all other characters examined, the variation found in dahli encompasses the values found in T. pacifica. While it has been demonstrated many times that color is of dubious value in diagnosing ant species, lack of intermediate forms in sympatric populations of T. dahli and T. pacifica on Espiritu Santo, Vanuatu, suggests these are good species.

Distribution based on Regional Taxon Lists
Indo-Australian Region: New Guinea, Solomon Islands, Vanuatu.

Nomenclature

 *  dahlii. Turneria dahlii Forel, 1901b: 17 (w.) NEW GUINEA (Bismarck Archipelago). Wilson, 1962c: 17 (q.). See also: Shattuck, 1990: 109.

Holotype (unique syntype) from Kabakaul, Bismarck Archipelago, Papua New Guinea. Although Forel (1901) reported the type specimen as being collected at Ralum, Bismarck Archipelago, the apparent type in the Forel Collection (MHNG) indicates the specimen is from "Kabakaul, Bism. Archip." (=Bismarck Archipelago). The type locality is taken as specified on the specimen rather than as published by Forel (1901).

Description
This widespread species exhibits a large amount of morphological variation. In addition to the metric characters, it shows considerable variation in the shape of the mesonotum and basal face of the propodeum. The mesonotum (in profile) varies from only slightly arched to rather strongly rounded. The basal face of the propodeum (also in profile) varies from moderately arched to more or less flat. Both of these characters are fairly labile and extremes can be found within single nest series.

Worker measurements (n=47): OOD 0.18-0.26, EL 0.20-0.27, OCD 0.10-0.14, CL 0.14-0.23, HL 0.67-0.86, LES 0.04-0.08, EW 0.11-0.16, ES 0.27-0.34, HW 0.61-0.80, SL 0.48-0.63, PnL 0.31-0.45, ML 0.24-0.37, PpL 0.20-0.30, PnW 0.40-0.57, MW 0.24-0.34, PpW 0.23-0.32, PO 0.04-0.08, FFL 0.49-0.65, FFW 0.19-0.26, MH 0.36-0.51, PpH 0.25-0.37, CI 0.88-0.98, OI 0.53-0.63, REL 0.29-0.37, SI 0.72-0.85, FI 0.32-0.47, PI 0.61-0.80, PpI 0.71-1.07, ROOD 0.26-0.35, POI 0.10-0.31, RPO 0.04-0.12, RMW 0.37-0.46, RLES 0.05-0.13, RES 0.41-0.50, RFFL 0.73-0.86.

Definitions of measurements cited above
 * CL: Clypeal Length: measured in full face view.
 * CI: Cephalic index: HL/HW.
 * EL: Eye Length: measured in full face view.
 * ES: Eye Spread: distance between inner-most edges of eyes measured in full face view.
 * EW: Eye width measured in full face view.
 * FFL: Fore Femur Length: maximum length of fore femur measured in lateral view.
 * FFW: Fore Femur Width: maximum width of fore femur measured in lateral view.
 * FI: Femur Index: FFW/FFL.
 * HL: Head Length: maximum length of head in full face view, from the anterior clypeal margin to the midpoint of a line drawn across the occipital margin.
 * HW: Head Width: maximum width of head in full face view, excluding eyes in workers and queens, including eyes in males.
 * LES: Lateral Eye Space: distance from lateral edge of head to lateral edge of eye measured in full face view.
 * MH: Mesothoracic Height: maximum height of the mesothorax measured perpendicular to the measuring axis.
 * ML: Mesonotal Length: distance from the pronotal-mesonotal suture to the metanotal groove measured parallel to the measuring axis.
 * MW: Mesonotal Width: minimum width of mesonotum in dorsal view profile.
 * OCD: Ocular-Clypeal Distance: distance between anterior margin of eye and posterior margin of clypeus measured in full face view.
 * OI: Ocular Index: EW/EL.
 * OOD: Occiput-Ocular Distance: distance between posterior margin of eye and posterior extremity of occipital border measured in full face view.
 * PI: Pronotal Width Index: PnW/HW.
 * PnL: Pronotal Length: distance from the anterior edge of the pronotal collar to the pronotal-mesonotal suture measured parallel to the measuring axis.
 * PnW: Pronotal Width: maximum width of pronotum, measured in dorsal view.
 * PO: Propodeal Overhang: distance from the posterior-most point of the propodeal tubercles to the posterior-most point of the petiolar insertion measured parallel to the measuring axis.
 * POI: Propodeal Overhang Index: PO/PpH.
 * PpH: Propodeal Height: maximum height of the propodeum measured perpendicular to the measuring axis.
 * PpL: Propodeal Length: distance from the metanotal groove to the posterior-most point of the propodeal tubercles measured parallel to the measuring axis.
 * PpI: Propodeal Length Index: PpL/HW.
 * PpW: Propodeal Width: maximum width of the dorsal propodeal surface in dorsal view.
 * REL: Relative Eye Length: EL/HW.
 * RFFL: Relative Fore Femur Length: FFL/HW.
 * RES: Relative Eye Spread: ES/HW.
 * RLES: Relative Lateral Eye Space: LES/HW.
 * RMW: Relative Mesonotal Width: MW/HW.
 * ROOD: Relative Occiput-Ocular Distance: OOD/HW.
 * RPO: Relative Propodeal Overhang: PO/HW.
 * SI: Scape index: SL/HW.
 * SL: Scape Length: length of the first antennal segment (scape) excluding the basal radicle.

Queen description: Three alate queens are known of this species; they are discussed by Wilson (1962). Shattuck (1990) supported Wilson's tentative placement of the Rennell Island specimen as a member of this species. The elongate head (CI 1.28), the relative scape length (SI 0.83), and the uniform dark brown color are more similar to known dahli queens (CI 1.25, 1.26; SI 0.80, 0.84; uniform color) than those of pacifica (CI 1.20-1.21; SI 0.76-0.79; bicolored (n=4)). The Rennell Island specimen does, however, differ from the two New Britain queens in two respects. First, it contains numerous erect hairs on the lateral margin of the head between the posterior edge of the eye and the occipital corner. The two dahli queens have at most three hairs in this region. Secondly, the specimen has the M-C crossvein joining the M distal of the Rs-M separation. In the other two queens, the junction of the M-C crossvein and the separation of Rs and M occur within a distance approximately equal to the width of a vein, or less. In both of these characters, the Rennell Island queen resembles pacifica more closely than dahli. The relative lengths of 2r and Rs+4, listed as a separatory character by Wilson (1962), were found too variable to be of use.