Proceratium sali, Hita Garcia, Francisco, Hawkes, Peter G. & Alpert, Gary D., 2014

Hita Garcia, Francisco, Hawkes, Peter G. & Alpert, Gary D., 2014, Taxonomy of the ant genus Proceratium Roger (Hymenoptera, Formicidae) in the Afrotropical region with a revision of the P. arnoldi clade and description of four new species, ZooKeys 447, pp. 47-86 : 62-63

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scientific name

Proceratium sali

sp. n.

Taxon classification Animalia Hymenoptera Formicidae

Proceratium sali sp. n. Figs 3C, 6B, 7B, 16A, 16B, 16C, 18

Type material.

Holotype, pinned worker, TANZANIA, Morogoro, Ulanga, Sali Forest Reserve, 8.94497S, 36.67261E, 1150 m, primary forest, collection code CEPF-TZ-9.1, 17.-20.X.2007 (P. Hawkes, M. Bhoke & U. Richard) (SAMC: CASENT0235689).


The following character combination separates Proceratium sali from the other Afrotropical members of the Proceratium arnoldi clade by the following combination of characters: eyes very small, consisting of three to four weak ommatidia (OI 5); CI 94; maculae on vertexal angles of head well developed and conspicuous; petiolar node high nodiform, anteroposteriorly compressed, with anterior face relatively straight; petiole in dorsal view between 1.1 and 1.2 times wider than long (DPeI 116); ventral process of petiole well developed, lamelliform and rectangular, lamella not pointed anteriorly nor posteriorly; abdominal segment IV around 1.1 times longer than abdominal segment III (ASI 108); head, mesosoma and petiole with numerous long, fine, suberect to erect hairs on top of dense mat of much shorter decumbent to subdecumbent pubescence.

Worker measurements

(N=1). TL 3.35; EL 0.04; SL 0.55; HL 0.81; HLM 0.94; HW 0.76; WL 1.00; HFeL 0.62; HTiL 0.53; HBaL 0.41; PeL 0.31; PeW 0.36; DPeI 116; LT3 0.53; LS4 0.19; LT4 0.57; OI 5; CI 94; SI 68; IGR 0.33; ASI 108.

Worker description.

In full-face view head slightly longer than broad (CI 94), sides and vertex moderately convex. Clypeus medially reduced, its anterior margin convex to slightly triangular, only slightly protruding anteriorly, not surrounding the antennal sockets and not medially impressed, antennal socket with broad torulus. Frontal carinae relatively short and widely separated, not converging medially and strongly diverging posteriorly, partially covering antennal insertions; frontal carinae conspicuously raised on their anterior half, much less posteriorly. Eyes very small, consisting of three to four faint ommatidia (OI 5) and located on mid line of head. Mandibles elongate-triangular; masticatory margin of mandibles with four relatively small teeth/denticles, decreasing in size from larger apical tooth to basal denticle. Mesosoma weakly to moderately convex in profile and weakly longer than maximum head length including mandibles. Lower mesopleurae with well impressed sutures, no other sutures developed on lateral or dorsal mesosoma; mesopleurae extremely inflated posteriorly; propodeum in profile armed with very small, pointed teeth, propodeal lobes well developed, triangular and blunt; declivitous face of propodeum between teeth and lobes noticeably concave; in posterodorsal view sides of propodeum separated from declivitous face by margin connecting propodeal lobes and propodeal teeth. Legs slender and elongate; pro- and mesotibiae with pectinate spurs; calcar of strigil without basal spine. Petiolar node in profile high, blocky nodiform, anterior face of petiole relatively straight, anterior and posterior faces approximately parallel, dorsum of node flat to weakly convex; petiole in dorsal view between 1.1 and 1.2 times wider than long (DPeI 116), petiolar node in dorsal view clearly much broader than long; ventral process of petiole well developed, lamelliform and rectangular, lamella not pointed anteriorly nor posteriorly. In dorsal view abdominal segment III anteriorly broader than petiole; its sides diverging posteriorly; dorsum of abdominal tergum III with posteromedial, very conspicuous, semitransparent, flat bulla below the integument; abdominal sternite III anteromedially with a marked subtriangular projection. Constriction between abdominal segment III and IV conspicuously impressed. Abdominal segment IV strongly recurved (IGR 0.33), conspicuously rounded on its curvature, especially posteriorly, abdominal tergum IV only less than 1.2 times longer than abdominal segment III (ASI 116); large, semitransparent and semicircular bulla situated posteromedially on abdominal tergum IV; remaining abdominal tergites and sternites relatively inconspicuous and curved ventrally. Whole body covered with dense mat of relatively short, decumbent to subdecumbent pubescence; most of body with moderately abundant, much longer (several times longer than pubescence), suberect to erect, fine, standing hairs. Mandibles longitudinally rugose; most of body irregularly foveolate and/or granulate, sculpture best developed on cephalic and mesosomal dorsum, less so on mesosoma and especially weak on most of relatively smooth and shining abdominal tergum IV; inflated, posterior part of mesopleura and declivitous face of propodeum unsculptured, relatively smooth and shining. Head, mesosoma (excluding posteriorly inflated part of mesopleurae), postpetiole and remaining abdominal segments of brown colour, mandibles, inflated part of mesopleurae and legs yellowish to light brown.


The name of the new species is derived from the type locality, the Sali Forest Reserve in Tanzania. The species epithet is a noun in apposition and thus invariant.

Distribution and ecology.

Proceratium sali is only known from the Sali Forest Reserve in the Morogoro region of south-central Tanzania (Fig. 18). Sali covers an area of 1072 ha and is the largest of the seven reserves in the Mahenge mountain range. The forest is largely undisturbed with little evidence of logging and a fairly dense canopy cover (estimated at 80-90%). Altitude within the reserve ranges from approximately 1150 to 1480 m and the area surveyed was at the lower end of this range. The soil along the 230 m transect surveyed was moist sandy clay loam (hand soil texture classification) and approximately 90% covered by a 2-3 cm thick layer of leaf litter. The single Proceratium sali specimen was collected in pitfall trap 16 of 24 placed along the transect, and no further details of its microhabitat preferences can be determined.

Taxonomic notes.

Proceratium sali shares a thicker head in full-face view (CI 94) with Proceratium burundense , Proceratium lunatum , Proceratium nilo and Proceratium sokoke (CI 91-95), which contrasts with the thinner head of Proceratium arnoldi and Proceratium carri (85-87). In addition, Proceratium sali (as well as Proceratium carri , Proceratium nilo , Proceratium sali and Proceratium sokoke ) possesses numerous long, fine, standing hairs on top of a mat of much shorter pubescence distinguishing it from Proceratium arnoldi , Proceratium lunatum and Proceratium burundense that lack this type of pilosity. The two species most similar to Proceratium sali are Proceratium nilo and Proceratium sokoke , but the latter two have a lower, less compressed petiolar node with the anterior face strongly produced anteriorly on lower third. This contrasts strongly with the node of Proceratium sali that is high nodiform and more compressed with a straight anterior face.


As for Proceratium burundense , Proceratium nilo and Proceratium sokoke , Proceratium sali is also only known from a singleton holotype, which does not allow any conclusions on intraspecific variation.