Diacamma viridipurpureum

Little is known about the biology of . Unfortunately, it seems impossible to collect more material from the type locality, Antipolo, which is now a heavily populated area adjacent to the metropolis Manila.

Identification
Laciny et al. (2015) - Large species (TL 12.8–13.8 mm). Trunk with moderate, polychromatic shimmer, dark greenish and purple colours dominating. Mandibles, antennae and legs dark brown to black. Erect setae abundant; fine pilosity well developed. Trunk strongly striate from genae to gaster tergite 1. Head moderately long, sides posteriorly of eye strongly convex. Posterior of head longitudinally striate until narrowly truncated hind margin; occipital margin ventrally terminating in short, blunt teeth. Eyes rather small. Clypeus with very fine puncturation at base, becoming sparse anteriorly and usually lacking anteromedially; apex medially more or less rounded. Mandible with fine striation. Pronotum with transverse-elliptical rugae. Striation on propodeum sides strongly upcurved. Petiole very stout, its teeth moderately short; subpetiolar process strongly concave between acute anterior and posterior corners, with rather long, oblique pilosity. Gaster tergite 1 with coarse semi-circular striation.

Besides its colour, which always contains areas of distinct green and purple shimmer, D. viridipurpureum viridipurpureum can be best recognized by the clypeus which is scarcely punctured distally and has a medially rounded apical margin; further by eye size, strongly upcurved rugae at propodeum sides, and structure and pilosity of the subpetiolar process. See also comparative notes of Diacamma generali, Diacamma caeruleum, and Diacamma viridipurpureum quezonicum.

Distribution
Philippines: Luzon Island: Pampanga, Manila, Rizal (type locality Antipolo), Laguna. (Laciny et al. 2015)

Distribution based on Regional Taxon Lists
Indo-Australian Region: Philippines. Oriental Region: India. Palaearctic Region: China.

Nomenclature

 *  viridipurpureum. Diacamma geometricum var. viridipurpureum Emery, 1893g: 261 (w.) PHILIPPINES. Wheeler, G.C. & Wheeler, J. 1952c: 610 (l.). Subspecies of geometricum: Santschi, 1933d: 1. Subspecies of rugosum: Bolton, 1995b: 171; Zhou & Ran, 2010: 104. Status as species: Laciny, Pal & Zettel, 2015: 118. Current subspecies: quezonicum.

Worker
Laciny et al. (2015) - Lectotype: TL 13.57; HW 2.35; HL 3.00; EL 0.64; SL 3.26; PH 1.83; PL 1.26; PW 1.41; SpD 0.59; SpL 0.23; WL 4.40; MTL 2.58. Indices: CI 78; SI 139; PI 69; SpDI 42; SpLI 17; EI 27. Measurements of non-type material (n = 8): TL 12.85–13.83; HW 2.28–2.48; HL 2.90–3.26; EL 0.58–0.67; SL 3.20–3.52; PH 1.70–2.09; PL 1.20–1.43; PW 1.29–1.43; SpD 0.58–0.64; SpL 0.32–0.46; WL 4.34–4.92; MTL 2.45–2.90. Indices: CI 76–80; SI 136–142; PI 65–71; SpDI 43–49; SpLI 25–33; EI 25–28.

Structures: Head moderately elongate; sides strongly convex behind small eyes. Very coarse rugae present from genae to gaster tergite 1. Posterior of eyes, longitudinal rugae reaching narrow occipital margin. On ventral side of head occipital margin ending in a small, blunt tooth. Clypeus shiny, basally with very fine puncturation, becoming sparse anteriorly and usually completely absent from apical lobe; anterior margin medially rounded, or a very obtuse angle recognizable. Mandibles usually with well-developed fine striation. Pronotum with transverse-elliptical rugae. Rugae on mesopleura almost horizontal, on propodeum sides strongly upcurved. Posterior face of propodeum separated from sides by distinct carinae. Petiole stout, with rather short spines; subpetiolar process strongly concave, both teeth very acute, posterior one usually strongly protruding; in lateral view, outline with long pilosity; in ventral view with distinct median carina and lateral carinae in anterior two thirds. Gaster tergite 1 with thick, concentric, semi-circular or semielliptical rugae; along posterior margin finely punctured. Gaster tergite 2 with very fine puncturation, shiny.

Pilosity: Standing setae on trunk long and numerous, on mesosoma slightly shorter than on head and gaster. Short appressed pilosity moderately developed, densest on head sides in front of eyes, hind margin of pronotum, mesonotum, dorsal face of propodeum, and petiole. Standing setae on legs about as long as those on mesosoma, setae on scape distinctly shorter.

Colour: Trunk with distinct metallic shimmer, usually greenish, with some purple reflections mostly on sides and gaster tergite 2, but often also with some bluish areas; apex of gaster brown. Mandibles dark brown. Antennae and legs black, with or without weak bluish-green shimmer; tarsi dark brown.

We narrowly define D. viridipurpureum viridipurpureum based on morphologically similar populations from Central Luzon, but similar distinguishable forms occur on southern areas of Luzon and some central and southern Philippine islands (compare description of D. v. quezonicum; and Wheeler & Chapman 1925 listing var. viridipurpureum from nine islands). The lectotype of D. viridipurpureum differs by very small (short and thin) petiolar spines, but otherwise agrees well with the other examined specimens. Therefore we consider this as an individual variation.

Unfortunately, it seems impossible to collect more material from the type locality, Antipolo, which is now a heavily populated area adjacent to the metropolis Manila.

Type Material
Laciny et al. (2015) - Lectotype (worker, present designation,, CASENT0903875, see Antweb 2015), “Antipolo Philippin Simon”, “Diacamma geometricum var. viridipurpu-reum. Em.”, “SYNTYPUS Diacamma geometricum var. viridipurpureum Emery, 1893”, “MUSEO GENOVA coll. Emery (dono 1925)”

''Diacamma geometricum var. viridipurpureum'' was described based on two workers from Antipolo in Rizal Province, Central Luzon (Emery 1893). These specimens belong to two different species which do not have much more in common than the polychromic metallic shimmer. We select specimen CASENT0903875 as the lectotype of D. viridipurpureum. For the second specimen we cannot provide a name at present. It belongs to a species closely related to Diacamma vagans and possesses similarly large eyes. So far we have not seen any further specimen of the same species.

One of the D. viridipurpureum viridipurpureum specimens in was used by Mayr (1862) for the description of the genus Diacamma, under the name Diacamma rugosum.



Determination Clarifications
When describing Ponera versicolor from Sarawak, Smith (1857) also included specimens from the Philippines without further locality information. According to current state of knowledge all species of the D. rugosum complex have relatively small ranges of distribution and we do not know of any species that occurs both on Borneo and the Philippines. Therefore the Philippine syntypes are probably not conspecific with those from Sarawak. A lectotype of Ponera versicolor should be selected from Sarawak. A Philippine syntype specimen of D. versicolor (CASENT0900672) is illustrated by Antweb (2015) and probably belongs to D. viridipurpureum.

Two further specimens illustrated in Antweb (2015) under the name D. rugosum viridipurpureum are in need of further examination. Specimen FMNHINS0000050354 from “Massisiat” in Abra Province is from the same locality (with different collector and collection date) as a paratype of D. generali and probably belongs to this species. However, neither in the featured images of this specimen nor of the specimen CASENT0217517 from Olongapo in Zambales Province are the species-specific characteristics are completely visible. The record of D. viridipurpureum from Sulawesi (Emery 1897) is incorrect. We examined the specimen in MCSN on which it was based; it differs from D. viridipurpureum by more densely punctured, orange-coloured clypeus, pale mandibles, relatively long setae on scapes, and morphometric characters. At present we cannot relate it to any described taxon.