Dolichoderus furcifer

A population from Danau Maninjau is associated with Archeomyrmococcus dolichoderi. The mealybugs are carried spontaneously as well as after disturbances in great numbers, which indicates a herdsmen lifestyle. Three mounted specimens of the series from Nias (UDSB) still held mealybug larvae of the same Allomyrmococcini genus in their mandibles. (Dill 2002)

Identification
Dill (2002) - Together with Dolichoderus brevithorax and Dolichoderus cuspidatus, Dolichoderus furcifer forms a complex of very similar species (see also discussion of these species). Similar to the situation in brevithorax, little material of furcifer was available for examination (four series from two regions, Sumatra and Nias). The material from Sumatra consisted of two nest-series from Lake Maninjau in West Sumatra and of the type series.

Regarding a number of characters, such as sculpturing, colour, body size, shape of pronotum and mesonotum, shape and length of the mesonotal spines, furcifer falls within the range of variation of the herein broadly defined cuspidatus. However, compared to cuspidatus, furcifer is generally stouter. A suitable diagnostic character that reflects this difference is the minimum propodeal width index (PpWminI) which sets the width of the propodeum (measured in full face view at its narrowest point) in relation to the body size (see also Figs. III-86 and III-87). Furthermore, furcifer can easily be distinguished, at least from the sympatric or parapatric Sumatran populations of cuspidatus, by several other characters: (1) head usually with a distinct median superoccipital pit (particularly well developed in West Sumatra), (2) mesonotal spines shorter and blunter (fig. III-88), (3) process of mesopleuron at best forming a very flat hump, (4) propodeal spines broader, plumper, and hardly spatulate at the tips (compare Figs. III-9e,g, l-m with III-5a-j), (5) apical margin of petiole scale entire, not or only very weakly emarginate (compare Figs. III-9f,h-i, n-o with III-5 k-v).

Yet, regarding the development of these characters, furcifer falls within the range of variation of some Bornean populations of cuspidatus. Particularly the population from East Kalimantan comes morphologically very close and resembles furcifer for instance in the shape of the mesopleuron process and the petiolus. D. furcifer can further be distinguished from brevithorax by the longer mesonotal spines and the broader and more edged pronotum of the former.

The material from Nias (originally described by Menozzi 1932) differs from the West-Sumatran material mainly in a slightly more emarginate petiole scale, a weaker developed or entirely missing superoccipital pit, and very scarce pubescence of the gaster. However, all these characters proved to be very variable intraspecifically in other Dolichoderus species as well.

Distribution
Dill (2002) - Sumatra: West-Sumatra and the Island of Nias.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Indonesia.

Nomenclature

 *  furcifer. Dolichoderus furcifer Emery, 1887a: 256 (w.) INDONESIA (Sumatra). Combination in D. (Hypoclinea): Emery, 1894c: 229; in D. (Diabolus): Wheeler, W.M. 1935c: 68. See also: Dill, 2002: 43.

Worker
Dill (2002) - Syntype from MCSN in [ ]): HL 1.28-1.57 [1.53]; HW 1.30-1.71 [1.57]; EL 0.24-0.36 [0.36]; SL 1.12-1.32 [1.31]; AL 1.81-2.31 [2.20]; PnW 0.92-1.20 [1.12]; MWmin 0.30-0.45 [0.41]: MH 0.40-0.59 [0.51]; MSW 0.58-0.93 [0.93]; MSL 0.36-0.53 [0.53]; PpL 0.64-0.90 [0.86]; PpW 0.64-0.80 [0.78]; PpWmin 0.38-0.51 [0.49]; PpH 0.78-0.94 [0.86]; PpSW 0.58-0.76 [0.73]; PtW 0.53-0.67 [0.66]; TL 5.43-6.44 [5.91]. Indices: CI 100-112 [103]; OI 20-25 [23]; SI 73-90 [84]; MSLI 26-34 [34]; MSWI 43-59 [59]; PpWminI 27-34 [31]: (n = 49).

Head: From reddish-brown to black-brown and black (type); very finely reticulate (= micro-imbricate) and scattered punctate; shining; with scattered, short pubescence, void of erect hairs. Head usually somewhat wider than long, broadest just behind the eyes, rounded heart-shaped; often with shallow yet distinct median superoccipital pit; often additional lateral impressions anterior of occipital margin.

Alitrunk: Reddish-brown, blackish-brown or black, legs castaneous to black; finely reticulate-punctate (= micro-imbricate), partly (mesonotal spines, dorsal face of propodeum) rugose; matt to weakly shining; pubescence scarce to dense, erect hairs scarce and restricted to ventral side and coxae. Dorsal face of pronotum with ± distinct lateral edges; shoulder corners rounded yet distinct; mesonotum hump broad, bearing a pair of slightly sideways inclined spines (figs. III-9d, III-9j-k); spines of moderate length; mesonotal spines more slender than those of propodeum; process of mesopleuron only weakly developed, forming a broad, flattened hump; propodeum proportionally very robust and broad (see PpWrninI); its dorsal corners expanded to a pair of short spines, which are ± broad over their full length and inclined sidewards and slightly backwards, their tips blunt but usually not spatulate (figs. III-9e,g, l-m).

Petiole: Finely reticulate and moderately shiny; apical margin of scale flattened and ± entire, not or only very shallowly emarginate (figs. III-9f, h-i,n-o).

Gaster: Reddish-brown, castaneous to black, basal parts of tergites usually lighter (yellow or reddish); finely reticulate; densely (W-Sumatra) to sparsely (Nias) pubescent; dorsal pubescence merging in a median line; erect hairs sparse, restricted to ventral face and gaster tip.

Type Material
Dill (2002) - Syntype worker, Sumatra, Ajer Mantcior (O. Beccari) [examined].

“Sumatra, Ajer Mantcior” which most probably is Beccari's italianized spelling of Maninjau (“Ajer” is pronounced in the same way as “Air” the Indonesian word for water or body of water; “Mantcior” might rather be “Manintcior” which is an old spelling for Maninjau). Furthermore, Beccari’s other collection locations of the same collecting trip all lie near Lake Maninjau, between Padang and Bukillingi. Thus it is very likely that all Sumatra material examined comes from the same location. The material from Nias consists of a single series.