Proceratium deelemani

The type worker was collected from sifted forest litter.

Identification
A member of the goliath group (stictum clade) and in an unresolved position in a small group containing two other species, Proceratium stictum and Proceratium foveolatum, but resembling more stictum, and differing from it in the worker by the frontal carinae more divergent posteriorly, by the shorter hind basitarsi (HTiL/HBaL ≥ 1.28 instead of ≤ 1.19) and by the head sculpture deeper.

Distribution
Borneo, Brunei Darussalam, Malaysia (Sabah and Sarawak), Thailand and Singapore.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Borneo, Brunei Darussalam, Indonesia, Malaysia, Singapore. Oriental Region: Thailand. Palaearctic Region: China.

Nomenclature

 * . Proceratium deelemani Perrault, 1981: 189, figs. 1-6 (w.) BORNEO (Indonesia: Kalimantan).
 * Type-material: holotype worker.
 * Type-locality: Indonesia: Kalimantan (“Borneo”), Sépaku, 40 km. NNW Balikpapan, 16.vii.1979, leaf litter, primary forest (C. & R. Deeleman).
 * Type-depository: MNHN.
 * Baroni Urbani & De Andrade, 2003b: 97 (q. putative m.).
 * Status as species: Bolton, 1995b: 366; Baroni Urbani & De Andrade, 2003b: 91 (redescription); Jaitrong & Nabhitabhata, 2005: 41; Pfeiffer, et al. 2011: 58; Liu, C., Guénard, et al. 2015: 56.
 * Distribution: Brunei, China, Indonesia (Kalimantan), Malaysia (Peninsula, Sabah, Sarawak), Singapore, Thailand.

Baroni Urbani and de Andrade (2003) - The most significant variation observed among the Proceratium deelemani workers we studied are in the size of the propodeal spiracle: only in the worker from Posing Hot Springs it is as large as in the holotype. The specimens from Thailand have the head dorsum more rugulose and the foveae much more irregular than the holotype; some specimens have the postpetiole with the sides diverging on the anterior half and convex on the posterior half and others have it entirely convex. We can not exclude that the collection of additional material may allow the separation of one or more additional species within what we presently regard as deelemani.

The attribution of the male from Brunei to deelemani needs confirmation. The male in question has propodeal spiracles as large as the Holotype worker. What we regard as a single, variable species, deelemani, however, is, together with foveolatum, one of the two sole species and the commonest one of the stictum clade reported from Borneo so far.

Worker
Baroni Urbani and de Andrade (2003) - Head slightly longer than broad, narrower anteriorly than posteriorly. Vertex in full face view almost straight. Clypeus broad, convex, protruding anteriorly and surrounding the whole antennal insertions. Anteromedian margin of the clypeus notched medially. Frontal carinae far from each other, strongly diverging posteriorly and not covering the antennal insertions. Floor of the frontal carinae concave medially. Lateral expansions of the frontal carinae narrow and slightly raised. Genal carinae present, strongly marked, prolonging towards the hypostomal bridge and bounding an impressed gular area. A superficial sulcus is present between the genal carinae and the gular area. Eyes present, composed by a convex facet each, and placed slightly below the mid line of the head. Ocelli absent. Scapes thick, distally incrassate, and far short of the vertexal margin. First funicular joint as broad as long. Funicular joint, 2-10 broader than long. Last funicular joint as long as the sum of joints 7-11. Mandibles with 3 denticles before the apical tooth. Palp formula 4,3.

Mesosoma slightly longer than the head (mandibles included), convex in side view. Promesonotal and propodeal sutures weakly impressed. Promesopleural suture impressed on the ventral half only. Basal face of the propodeum slightly convex and declivous posteriorly. Declivous face of the propodeum flat; sides of the declivous face marginate. Propodeum with a pair of relatively long, large spines between the basal and declivous faces. Propodeal lobes ventrally truncate and dorsally with a long, round tooth protruding dorsally. Postero-median part of the metapleurae with a superficial concavity sheltering the propodeal spiracle. Propodeal spiracles large or small (see discussion).

Petiole about as broad as long, in dorsal view with the sides diverging on the anterior third and convex posteriorly. Anterior border of the petiole straight and with a thick margin slightly denticulate on each side. Ventral process of the petiole corresponding to a longitudinal lamella posteriorly denticulate. Postpetiole slightly shorter than gastral tergite I (LT4). Postpetiole in side view with a tumulus close to the posterior border and in dorsal view with broadly convex sides. Postpetiolar sternite anteromedially with a marked subtriangular projection. Posterior half of the postpetiolar sternite slightly convex. Constriction between postpetiole and gastral segment I deeply impressed. Gastral tergite I strongly rounded. Gastral sternite I very short medially. Remaining gastral tergites and sternites curved ventrally.

Legs elongate. All tibiae with a pectinate spur. Spurs of fore legs with a basal spine. Fore basitarsi slightly longer than the mid ones. Hind basitarsi about 0.75 of the length of the hind tibiae. Second tarsomere of mid and hind legs longer than third and fourth tarsomeres, and shorter than pretarsus. Pretarsal claws simple. Arolia small.

Sculpture. Head, mesosoma, petiole and postpetiole foveolate with superimposed punctation and granulation, the foveae deep, relatively large and irregular. Gaster smooth, its sides and posterior border granulopunctate and slightly foveolate-rugulose. Scapes and legs strongly granulate.

Body covered by hairs of three main types: (1) short, dense, subdecumbent on the whole body, suberect and sparse on the funicular joints; (2) suberect, long, relatively dense on the whole body, absent from the antennae; (3) shorter than hair type (I), dense, decument or appressed on the funicular joints only. In addition the funicular joints bear whitish, thick, appressed, short, sparse hairs and the scapes with sparse hairs shorter than hair type (2).

Colour dark fenugineous-brown with lighter legs.

Measurements in mm and Indices: TL 3.87-4.68; HL 0.92-1.14; HW 0.88-1.10; EL 0.07-0.08; SL 0.61-0.78; WL 1.08-1.40; PeL 0.41-0.53; PeW 0.37-0.52; HFeL 0.73-1.04; HTiL 0.63-0.86; HBaL 0.45-0.67; LS4 0.16-0.22; LT4 0.68-0.82; CI 92.6-96.7; SI 62.4-68.5; IGR 0.23-0.29.

Queen
Baroni Urbani and de Andrade (2003) - (description based on a single specimen). It differs from the worker in the following details: eyes about 1/5 of the head length. Ocelli well developed. Mandibles with 3 teeth before the apical tooth. Mesosoma robust and convex in side view. Scutellum large; its sides gently converging to a subconvex posterior border. Metanotum with a large spine. Each side of the basal face of thc propodeum with a broader spine. Median dorsum of the basal face of the propodeum impressed and almost on the same plane as the declivous face. Lower half of the propodeal lobes truncate. Metapleural concavity deeper. Petiole as long as broad. Postpetiole about 1/3 shorter than gastral tergite I (LT4). Hind basitarsi about 1/5 shorter than hind tibiae.

Sculpture and pilosity as in the worker.

Colour. Dark ferrugineous-brown with lighter legs.

Measurements in mm and Indices: TL 5.66; HL 1.20; HW 1.18; EL 0.23; SL 0.81; WL 1.70; PeL 0.56; PeW 0.56; HFeL 1.18; WTiL 0.93; HBaL 0.75; LS4 0.26; LT4 1.14; CI 98.3; SI 67.5; IGR 0.23.

Male
Baroni Urbani and de Andrade (2003) - (tentative attribution). Head broader than long. Vertex in full face view convex and in posterior view flat. Vertexal margin medially carinate. Clypeus convex; its anterior border superficially crenulate on the sides and weakly notched medially. Frontal carinae thin, low, short, parallel and far from each other. Floor of the frontal carinae weakly impressed. Ocelli large. Compound eyes about half of the head length. Scapes not reaching the anterior border of the anterior ocellus. First funicular joint about 1/2 of the length of the second. Joints 2-11 longer than broad. Last funicular joint slightly longer than the sum of joints 10-11. Mandibles as in stictum, edentate and only with a pointed apical tooth. Palp formula 4,3.

Mesosoma robust. Pronotum and anterior third of mesonotum almost perpendicular to the posterior two thirds of the mesonotum. Posterior two thirds of mesonotum nearly flat. Parapsidal furrows superficially marked. Scutellum as high as the mesonotum and dorso-medially with an impressed sulcus; posterior border of scutellum subround. Sides of the basal face of the propodeum with a triangular tooth separate from the other tooth by an incision. Declivous face of the propodeum flat and weakly marginate on the sides. Propleurae without incision. Metanotum with a median spine-like projection. Propodeal lobes subround, size similar to the one of stictum and smaller than in foveolatum. Propodeal spiracle well developed as in the holotype worker.

Petiole in side view convex, about 1/5 longer than broad. Sides of the petiole in dorsal view parallel on their anterior fifth and gently convex posteriorly. Anterior border of the petiole truncate, strongly carinate and with a denticle on each side. Subpetiolar process small and subround. Postpetiole anteriorly slightly broader than the petiole; postpetiolar sides diverging or gently convex posteriorly. Anterior border of the postpetiolar sternite with a Y-shaped carina. Posterior half of the postpetiolar sternite gently convex.

Gastral tergite I round. Gastral sternite I ventrally broader than in foveolatum. Remaining gastral tergites and sternites slightly curved ventrally.

Legs less stouter than in the worker.

Fore wings of our type 3, hind wings of our type 2 as defined in the description of the genus.

Genitalia not dissected.

Sculpture. Head, mesosoma and petiole covered by dense, small, irregular foveae, slightly larger on the scutellum, more superficial on the mesopleurae; on some areas the foveae separate by thin, irregular rugosities. Anterior half of the postpetiolar dorsum with large piligerous foveae. Posterior half of the postpetiolar dorsum and postpetiolar sternite with sculpture similar to the one of the petiole. First gastral tergite with minute piligerous foveae; its posterior border with sculpture similar to the petiole. Legs with minute piligerous foveae.

Pilosity as in the worker but with the hair type (1) less dense on the scutellum, on the postpetiole and on the gaster, and hair type (2) shorter on the petiole and longer on the scutellum and on the gaster.

Colour. Black with shining postpetiole and gaster.

Measurements in mm and Indices: TL 4.37; HL 0.78; HW 0.90; EL 0.39; SL 0.34; WL 1.48; PeL 0.49; PeW 0.39; HFeL 0.98; HTiL 0.79; HBaL 0.61; LS4 0.33; LT4 0.88; CI 115.4; SI 43.6; IGR 0.37.

Type Material
Baroni Urbani and de Andrade (2003) - Type locality: Borneo. Type material: holotype worker labelled: "Borneo, 16-7- 1979, Sepaltan, Balikpapan, RC Deeleman, Type", in, examined.

References based on Global Ant Biodiversity Informatics

 * Baroni Urbani C., and M.L de Andrade. 2003. The ant genus Proceratium in the extant and fossil record (Hymenoptera: Formicidae). Museo Regionale di Scienze Naturali, Monografie 36: 1-480.
 * CSIRO Collection
 * Eguchi K., and S. Yamane. 2003. Species diversity of ants (Hymenoptera, Formicidae) in a lowland rainforest, northwestern Borneo. New Entomol. 52(1,2): 49-59.
 * Hashimoto Y., Y. Morimoto, and M. Mohamed. 2003. Species List of Ground and Leaf Litter Ants Collected in Lower Kinabatangan. Pp 13-18. In Lower Kinabatangan Scientific Expedition 2002, 176 pp. ISBN-13: 983-2369-11-8
 * Jaitrong W., and T. Ting-Nga. 2005. Ant fauna of Peninsular Botanical Garden (Khao Chong), Trang Province, Southern Thailand (Hymenoptera: Formicidae). The Thailand Natural History Museum Journal 1(2): 137-147.
 * Jaitrong W.; Nabhitabhata, J. 2005. A list of known ant species of Thailand. The Thailand Natural History Museum Journal 1(1): 9-54.
 * Liu C, B. Guénard, F Hita Garcia, S. Yamane, B. Blanchard, and E. Economo. New records of ant species from Yunnan, China. Submitted to Zookeys
 * 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