Pheidole furcata, Sarnat, E. M., 2008

Sarnat, E. M., 2008, A taxonomic revision of the Pheidole roosevelti-group (Hymenoptera: Formicidae) in Fiji., Zootaxa 1767, pp. 1-36 : 19-20

Pheidole furcata Sarnat sp. n.

Figs. 38-40, 59-61, 80-82

Holotype major, FIJI: Kadavu, Mt. Washington 1.4 km SSW Lomaji Village, 5.ix.2006, 760m, -19.11806°, 177.98750°, high elevation moss forest, turret nest in bare soil, (E. M. Sarnat), EMS#2407, CASENT0171111, ( FNIC).

Paratypes. From same nest series as holotype: 4 dealate queens (CASENT0171112, CASENT0174063, CASENT0174069, CASENT0174072), 11 majors (CASENT0171111, CASENT0174060, CASENT0174061, CASENT0174064, CASENT0174066, CASENT0174067, CASENT0174070, CASENT0174073, CASENT0174075, CASENT0174076, CASENT0174078, CASENT0174079), 8 minors (CASENT0171025, CASENT0174062, CASENT0174065, CASENT0174068, CASENT0174071, CASENT0174074, CASENT0174077, CASENT0174080), ( FNIC, NMNH, ANIC, MCZ, LACM); additional specimens in alcohol( NMNH).

MAJOR. TL 6.01-6.61, HL 1.95-2.04, HW 1.82-1.96, CI 0.92-0.96, FL 1.31-1.41, FI 0.64-0.72, SL 0.99-1.04, SI 0.49-0.53 (7 measured).

Head with sides not distinctly broader posterior to eyes than anterior to eyes. Median ocellus absent in all specimens examined. Mesonotal process produced as a thick lamellate plate overhanging propodeum; in dorsal view attachment to mesonotum broad, posterior margin flat to excised. Propodeal spines maintaining an evenly stout thickness for basal 4/5 length whereupon the anterior edge angles obliquely towards the posterior edge to form a posteriorly projecting acuminate tip. Petiole node, in posterior view, moderately excised. Postpetiole taller than long; as tall as petiole; steep anterior and posterior faces converging to form an obtusely angulate vertex; in dorsal view subpentagonal with modest lateral projections.

Region between frontal carinae with straight longitudinal carinae that extend unto vertex before integrating with a finely produced rugoreticulum on the posterolateral lobes. Posterolateral lobes, in full face view, with rugoreticulum terminating before obtaining posterior margin. Intercarinular spaces smooth and shining between frontal carinae; moderately foveolate on vertex and posterolateral lobes. Eye surrounded by elevated carinae. Antennal scrobe foveolate and overlain by short carinae. Clypeus smooth and shining; anterior margin with several carinae laterally, some of which extend onto frontal lobes, median carina weak to absent. Lateral and ventrolateral portions of posterolateral lobes mostly smooth and shining, posteriorly with shallow oblong impressions. Head venter rugoreticulate. Promesonotum rugoreticulate. Anepisternum weakly rugoreticulate. Katepisternum weakly striate. Petiole with apical and posterior faces smooth, laterally and ventrally rugose. Postpetiole transversely rugose, sides rugose. Gaster costulate on basal quarter of first segment; sternite of first segment striate laterally; elsewhere smooth and shining. Body reddish-brown with lighter appendages.

MINOR. TL 3.55-3.85, HL 0.79-0.83, HW 0.72-0.77, CI 0.90-0.92, FL 1.09-1.15, FI 1.37-1.41, SL 0.99-1.05, SI 1.21-1.29, AE 0.29-0.31, DE 0.18-0.23, PSI 0.59-0.78 (8 measured).

Head, in full face view, subquadrate, sides weakly convex, posterolateral corners rounded and weakly obtuse, posterior margin flat to convex; in profile, posterior margin dorsoventrally pinched where dorsum and venter join at an obtuse angle. Genal carinae weakly produced on ventrolateral portion of head. Clypeus with anterior margin convex laterally, flat to weakly convex medially. Frontal carinae terminating near eye level or integrating with rugoreticulum. Mesonotal process produced as a short lamellate plate with upwardly deflected margins; in dorsal view, attachment to mesonotum broad, posterior margin flat to weakly concave. Propodeal spines thickening apically into a bifurcation with a short anterior point or angle and a long acuminate posterior point that projects at an oblique angle; length of dorsal edge less than length of anterior edge.

Head dorsally rugoreticulate with weak foveolate ground sculpture, ventrally smooth and shining. Clypeus with a few weak carinae attached to anterior border. Promesonotum, in dorsal view, mostly smooth and shining with a few weak and discontinuous transverse rugae. Anepisternum rugose. Katepisternum mostly smooth and shining. Reddish-brown with slightly lighter appendages.

QUEEN. TL 5.90-5.95, HL 1.14-1.17, HW 1.12-1.18, CI 0.98-1.01, SL 0.97-1.00, SI 0.84-0.85, FL 1.08-1.30, FI 0.94-1.11, ML 0.51-0.53, MI 0.94-1.01 (3 measured).

Head subquadrate with sides approximately as wide anteriorly as posteriorly. Mesoscutum, in profile, small, less than half height of pronotum; in dorsal view, not obscuring pronotum. Scutellum, in dorsal view, with posterior portion produced as a weakly elevated circular plate. Propodeal spines maintaining an evenly stout thickness for basal 4/5 length whereupon the anterior edge angles obliquely towards the posterior edge to form an acuminate tip. Petiole broadly cuneate; in posterior view, petiole node flat to weakly concave. Postpetiole, in dorsal view, subpentagonal with modest lateral projections.

Region between frontal carinae with straight longitudinal carinae that become rugoreticulate near posterior margin. Region between eyes and antennal insertions with crenulated rugoreticulum that continues to posterolateral corners; intercarinular spaces densely packed with foveolae. Head venter mostly smooth and shining, weak sculpture present medially. Antennal scrobe smooth and shining. Clypeus mostly smooth and shining; anterior margin with short carinae laterally, median carinae absent. Pronotum with scattered rugulae. Mesoscutum, in dorsal view, smooth and shining anteriorly with arcuate rugae laterally that curve towards median as they approach posterior margin. Scutellum mostly smooth and shining. Anepisternum rugoreticulate. Katepisternum mostly smooth and shining with weak rugulae. Petiole sculptured laterally and ventrally, anterior and posterior faces smooth and shining. Postpetiole with anterior face and dorsum rugulose. First tergite of gaster longitudinally sculptured basally, sculpture immediately posterior to postpetiole longer than length of postpetiole. First sternite of gaster sculptured basally. Body reddish-brown with lighter appendages.

Etymology. The specific epithet furcata is a noun in apposition derived from furca, the Latin word for fork, to describe the bifurcate propodeal spines of the species.

Diagnosis, distribution and biology. Pheidole furcata , owing to its strong facial sculpture, is most similar to P. bula and P. roosevelti in appearance. Whereas the facial sculpture of majors, in full face view, of P. bula and P. roosevelti reaches the posterior margin, that of P. furcata is conspicuously shorter, leaving the posterior margin smooth and shining. The minor of P. furcata is separated from these other two species by the completely smooth and shining ventral surface of its head.

Known only from Mt. Washington, P. furcata is also the only species of the P. roosevelti-group known from the southern island of Kadavu. Whereas many of the P. roosevelti-group species are locally abundant where they occur, no foragers of P. furcata were observed at the type locality during the afternoon spent on the mountain. The collection was made by locating the signature earthen turret entrance of a nest rising several cm above the surrounding bare soil. Like P. bula and P. colaensis , the queens of this species have strongly reduced mesosomas.