Pogonomyrmex intermedia Menozzi 1935 NEW STATUS

 

Pogonomyrmex (Ephebomyrmex) bispinosus var. intermedia Menozzi, 1935: 320 (worker). Syntypes examined: x workers [GGC] not examined, #204, CHILE, Bío Bío Region: Ñuble Province, Volcán de Chillan, 1700 m (Prof. W. Goetsch leg.).  

 

Pogonomyrmex (Pogonomyrmex) bispinosus var. intermedius Menozzi; Kempf, 1972: 207. First combination in Pogonomyrmex (Pogonomyrmex). Snelling & Hunt, 1976: 75 (synonomy under vermiculatus: not confirmed here). NEW STATUS

 

Worker

Diagnosis. Within the P. rastratus group, the combination of: (1) first gastric tergite lacking striae, (2) anterior face of petiole and peduncle meet at or near a right angle, and (3) ferruginous orange head and gaster with a darker, mostly blackish mesosoma uniquely characterize this species. 

Measurements (mm) - lectotype (n = 12). HL 1.40-1.79; HW 1.44-1.82; MOD 0.33-0.40; OMD 0.31-0.47; SL 1.09-1.35; PNW 1.00-1.22; HFL 1.32-1.82; ML 1.65-2.07; PW 0.36-0.49; PPW 0.54-0.70.  Indices: SI 69.89-80.25; CI 95.38-111.41; OI 19.89-24.31; HFI 87.91-110.60. 

Description.  Head subquadrate to quadrate (CI = 95.38-111.41); posterior margin flat to slightly convex in full-face view.  Longitudinal cephalic rugae prominent, in full-face view, median rugae diverging toward posterior corners of head.  Vertex rugose, interrugal spaces weakly to moderately granulate, sub-shining.  Cephalic interrugal spaces strongly granulate, dull.  Anterior margin of clypeus weakly to moderately concave, dorsum with several suparallel longitudinal rugae.  Mandible with six teeth; mandibular dorsum coarsely striated.  MOD ranging from 0.19-0.25x HL.  Eyes in profile situated slightly anterior to middle of head, OMD = 0.9-1.3x MOD.  In full-face view, eyes protruding slightly beyond lateral margins of head.  Antennal scapes (SI = 69.89-80.25) failing to reaching posterior corners of head by less than length of basal funicular segment.  Antennal scapes with weak longitudinal striae, weakly to moderately granulate, sub-shining; basal flange well developed with carinate margin.  Psammophore well developed. 

Mesosomal profile slightly to moderately convex.  In dorsal view, humeral portion of pronotum enlarged, slightly to distinctly angulate.  All mesosomal surfaces with prominent parallel/subparallel wavy to irregular rugae.  Anterior portion of pronotum rugoreticulate, irregular rugae on pronotal sides traverse ventrally or posterioventrally; rugae on mesopleura angle posteriodorsally.  Dorsum of promesonotum with longitudinal rugae that diverge anteriorly toward humeral angles.  Promesonotal suture often slightly to moderately impressed.  Propodeal spines acuminate, length approximately 0.5-0.7x the width between their bases, connected by a well-defined keel; irregular transverse rugae on dorsum of propodeum traverse ventrally or anterioventrally on sides.  Inferior propodeal spine well developed, broader than high, tapering to a blunt to subacute tip.  Propodeal spiracles narrowly ovate.  Interrugal spaces on mesosoma densely granulate, dull to sub-shining.  Legs sub-shining to shining.

Petiolar peduncle long, ventral surface often with a broad, rounded process.  In side view, dorsum of petiole slightly convex; petiolar node asymmetrical with anterior surface notably longer than posterior surface, apex subangulate to weakly rounded; anterior face meeting peduncle at a right angle.  In dorsal view, petiole longer than broad, widest near rounded anterior margin, gradually tapering to posterior margin.  Sides and dorsum of petiolar node with wavy to irregular transverse rugae.  Dorsum of postpetiole convex in side view; in dorsal view, widest near posterior margin, tapering to anterior margin, width and length similar.  Wavy, transverse rugae on dorsum of postpetiole that are finer and denser than those on petiole; interrugal spaces on petiole and postpetiole smooth and shining.  Dorsum of first gastric tergite smooth and shining to weakly coriarious, occasionally moderately coriarious near base giving the appearance of very faint longitudinal striae. 

Erect, mostly short to medium length, yellowish pilosity moderately abundant on head.  Moderately abundant suberect to semidecumbent pilosity on scape; abundant decumbent hairs on funicular segments.  Legs with moderately abundant suberect to decumbent yellowish setae.  Mesosoma, petiole, postpetiole, and gastric tergites with moderately dense, erect, yellowish setae that are similar in length; longest hairs on body not exceeding MOD.  Head and gaster ferruginous orange; mesopleura and propodeum dark brownish-orange; rest of body an intermediate orangish-brown to brownish-orange.

      Queen. Unknown.

Male. Unknown.

Additional material examined. CHILE: Ñuble: Las Trancas Road near Termas de Chillan, 1350m (CASC; LACM; RAJC)(the latitude-longitude on labels for this series is incorrect, as it places the collection in Colchagua Province).  

Etymology.  Mennozi described P. intermedia by comparing it to two other Chilean taxa, P. bispinosus and P. bispinosus var. semistriatus, indicating that the sculpturing of P. intermedia was similar to that of P. bispinosus var. semistriatus, and much more pronounced than in P. bispinosus, but that the gaster was smooth and shiny as in P. bispinosus (whereas the gaster of P. semistriatus has fine longitudinal striae).  Thus, the name intermedia appears to be derived from this species having a set of characters intermediate to those of P. bispinosus and P. bispinosus var. semistriatus.

REFERENCES

Kempf, W.W. (1972) Catálogo abreviado das formigas da Região Neotropical (Hym. Formicidae). Studia Entomologica, 15, 3-344.

Mennozi, C. (1935) Fauna Chilensis. 2 pars. Le formiche del Cile. Zoologische Jahrbücher. Abteilung für Systematik, Ökologie und Geographie der Tiere, 67, 319-336.

Snelling, R.R. & Hunt, J.H. (1975) The ants of Chile (Hymenoptera: Formicidae). Revista Chilena de Entomologia, 9, 63-129.