Diacamma vagans

Nothing is known about the biology of .

Identification
Laciny et al. (2015) - Relatively small species (TL ca. 10 mm). Trunk black, without metallic shimmer. Anterior part of head, larger part of gaster, mandibles, antennae, and legs pale to dark brown. Standing setae of moderate number and short; short pilosity dense, on dorsum partly obscuring surface sculpture. Striation relatively fine on dorsum of head and gaster tergite 1, coarse on head below eye, pronotum, propodeum, and petiole. Posterior of head longitudinally striate until narrow hind margin. Eyes large, protruding. Clypeus densely punctured, apex obtuse. Mandible with some large punctures, and obliterate striation. Pronotum transversely-elliptically striate. Propodeal striae almost horizontal, with fine ridges separating posterior from lateral faces. Petiole stout, node anteriorly rounded, its teeth short; subpetiolar process concave, anterior and posterior corner acute.

Diacamma vagans is a species with relatively delicate rugosity on the dorsum of the head, whereas the head of D. rugosum bears coarse rugae.

Distribution
Moluccas: Bacan Island. Other records from the literature probably refer to different species.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Indonesia, Singapore. Oriental Region: Nepal.

Nomenclature

 *  vagans. Ponera vagans Smith, F. 1860b: 103 (w.) INDONESIA (Batjan I.). Bingham, 1903: 81 (m.); Wheeler, G.C. & Wheeler, J. 1952c: 611 (l.); Imai, et al. 1984: 5 (k.). Combination in Diacamma: Mayr, 1862: 718. Subspecies of rugosum: Forel, 1908a: 1; Forel, 1912a: 49; Emery, 1911d: 67; Viehmeyer, 1916a: 113; Wheeler, W.M. 1919e: 54; Santschi, 1920g: 179; Forel, 1922: 90; Wheeler, W.M. 1927b: 42. Junior synonym of rugosum: Wilson, 1958d: 368. Status as species: Roger, 1860: 304; Mayr, 1862: 718; Mayr, 1863: 407; Roger, 1863b: 16; Mayr, 1867a: 87 (redescription); Mayr, 1886c: 361; Emery, 1887b: 440; Emery, 1889b: 497; Emery, 1893e: 190; Dalla Torre, 1893: 29; Emery, 1895k: 458; Bingham, 1903: 81; Mukerjee, 1934: 3; Laciny, Pal & Zettel, 2015: 106 (redescription).

Type Material
Laciny et al. (2015) - 1 worker (syntype,, CASENT0915957), “Ponera vagans Sm Batchian”, “Collect. G. Mayr”, “vagans det. G. Mayr”.

Smith (1860) described Ponera vagans from Bachian (Bacan Island, Moluccas, Indonesia). Two years later Mayr (1862) based the description of the genus Diacamma – among others – on the examined specimen and noted that he had received a specimen from F. Smith. We therefore consider this specimen in as a syntype of D. vagans. Antweb (2015) illustrates the “holotype” of D. vagans (specimen number CASENT0901344) which is deposited in the Museum Oxford. The two specimens show great similarity regarding their morphological characters. Morphometric analysis of the syntype and comparison with the illustrations provided by Antweb (2015) revealed that both specimens are of similar size (ca. 10 mm) and possess the same characteristic large eyes (EI > 30) and short petiolar spines (SpLI ca. 25).

Ponera vagans

Holotype worker in. Labelled “Bac” (= Batjan I.) and with a Donisthorpe type-label.

Taxonomic Notes
Laciny et al. (2015) - The name vagans has a long history as synonym or infraspecific taxon of Diacamma rugosum, or as a valid species (see Bolton 1995). It is not our aim at this time to fully clarify all synonymies of D. rugosum and D. vagans, but we can resolve the Moluccan D. vagans from synonymy with the Sunda-Land species D. rugosum. Diacamma vagans is a species with relatively delicate rugosity on the dorsum of the head, whereas the head of D. rugosum bears coarse rugae. There is also a big difference in eye size (EI ca. 27 in syntype specimen of D. rugosum, CASENT0913723, collected on Borneo deposited in MNHN Paris, illustrated by Antweb 2015). We have studied specimens from Borneo that are similar to the type, but slightly differ in sculpture. Therefore we presently do not give a morphological interpretation of D. rugosum s.str.

Worker
Laciny et al. (2015) - syntype (n = 1): TL 10.11; HW 1.78; HL 2.28; EL 0.58; SL 2.48; PH 1.38; PL 0.87; PW 0.93; SpD 0.44; SpL 0.23; WL 3.39; MTL 1.96. Indices: CI 78; SI 139; PI 63; SpDI 47; SpLI 25; EI 32.

Structures: Head elongate; sides strongly convex behind moderately large eyes. Rugae present from genae to gaster tergite 1, but very differently developed. Striation on head relatively fine, posterior of eyes longitudinal, reaching narrow occipital margin, on genae weakly developed, strongest below eyes. On ventral side of head occipital margin ending in a small rectangular tooth. Clypeus entirely punctured; apex of anterior margin narrowly rounded. Mandibles striate. Rugae on pronotum transverse-elliptical and with coarse, but less obvious because of narrow striation and dense pilosity. Rugae on mesosoma sides coarse, on pleural parts shallow and obscured by dense pilosity, dorsally on propodeum only slightly oblique. Carinae separating posterior face of propodeum from sides only ventrally weakly developed. Petiole stout, with coarse striae and rather short spines; subpetiolar process strongly concave and with dense, oblique, rather long pilosity in lateral aspect; both anterior and posterior tooth strongly developed and acute. Striation on gaster tergite 1 concentric, semi-circular, much finer than on mesosoma; a broad stripe along posterior margin of tergite 1 and the following tergites finely, but densely punctured, matt.

Pilosity: Standing setae on entire body including scape and legs short, except for a few long setae on clypeus and venter of head; those on petiole and gaster slightly longer than those on mesosoma. Short appressed pilosity dense, scarcer on sides of pronotum and weakly developed on sides of propodeum.

Colour: Trunk black, without metallic shimmer. Anterior part of head, venter and apex of gaster, posterior margins of gaster tergites 2–4, mandibles, antennae, and legs pale to dark brown.

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