Octostruma convallisur Longino

Longino, John T, 2013, A revision of the ant genus Octostruma Forel 1912 (Hymenoptera, Formicidae), Zootaxa 3699, pp. 1-61 : 25-27

Octostruma convallisur Longino , sp. nov.

(Figs 21, 44)

Type material. Holotype worker: PANAMA, Chiriqui: west of Finca Palo Santo near Nueva California [8.78, - 82.64, unknown error], 1550 m, 5 Mar 1959, debris at base of stump (H. S. Dybas) [MCZC, unique specimen identifier MCZ-ENT00511411]. Paratype queen, worker: same data [USNM, MCZ-ENT00511410; MCZC, MCZ-ENT00511415].

Geographic range. Panama, Colombia.

Diagnosis. Antennal scrobe very shallow, not distinctly margined; face with arcuate carina; frontal carinae and facial arc separated, the termini of the facial arc extend laterally beyond the termini of the frontal carinae (termini of facial arc join frontal carinae in O. ascrobis, O. ascrobicula ); facial arc not strongly elevated, becoming irregular and somewhat weaker laterally, frontal carinae stronger than lateral portions of facial arc (facial arc strong throughout, much stronger than frontal carinae in O. limbifrons ); promesonotal dorsum uniformly foveolate (pronotum smooth and shiny, differentiated from foveolate mesonotum in O. convallis ).

Description. Worker. HW 0.43-0.56, HL 0.43-0.55, WL 0.47-0.59, CI 100-102 (n=3). Labrum rectangular, formed of strap-like lateral portions joined by a thin translucent lamella (Fig. 1H); mandibles closed on available specimens, but appear generally similar to O. convallis ; dorsal surface of mandible smooth; scape flattened, with pronounced anterobasal lobe, dorsal surface with faint microsculpture, feebly shining; clypeus strongly emarginate anteriorly, smooth and shining; frontal carinae sharp, narrow, extending more or less straight back and ending before reaching transverse facial arc; facial arc broad, not strongly semicircular, extending toward sides of head beyond termini of frontal carinae, curving forward to form irregular carina or gibbosity between compound eye and frontal carina; a shallow trough separates frontal carinae and facial arc; frontal carinae and facial arc delimit anterior concave surface that is feebly shiny, with irregular median longitudinal carina and very faint rugulae laterally; side of head near compound eye shallowly foveolate; vertex posterior to facial arc largely smooth and shiny, with distinct, sparse, uniformly distributed puncta ; compound eye small, circular, composed of 4-5 somewhat confluent ommatidia; antennal scrobe below eye, very shallow and not delimited with carina or flange; scrobe and undersurface of head feebly foveolate to punctatorugose.

Promesonotum forming continuous convexity in profile; metanotal groove not impressed; posterodorsal propodeum a single, concave, sloping surface, not differentiated into dorsal and posterior faces; propodeal spines angular on holotype, acute and spiniform on Barro Colorado Island specimen, extending anteriorly as raised carinae that curve medially and join at the metanotal groove, extending ventrally as narrow lamella, thus posterodorsal propodeum entirely delimited by raised carinae confluent with propodeal spines; a low carina extends transversely across posterodorsal surface, between bases of propodeal spines; propodeal spiracle large, located immediately below propodeal spine and abutting posterior margin; promesonotum with feeble, mesh-like sculpture, juncture of pro- and mesonotum not differentiated; posterodorsal face of propodeum shallowly foveolate; side of pronotum smooth and shining; mesopleuron and side of propodeum matte.

Petiole in profile with peduncle not differentiated from node, anterior surface sloping evenly from petiolar foramen to node, dorsal face of node sloping posteriorly to projecting transverse cuticular rim, short concave posterior face beneath rim; anteroventral margin without tooth or angle; dorsal face of node smooth and shining; postpetiole low, broad, crescent-shaped in dorsal view, dorsal face shallowly foveolate anteriorly, smooth and shining posteriorly, delimited anteriorly and posteriorly by thin transverse rim; first gastral tergite shallowly foveolate anteriorly, grading to smooth and shining at posterior rim; first gastral sternite foveolate anteriorly, grading to sparsely punctate with smooth and shining interspaces posteriorly.

Labrum fringed on sides and apex with soft translucent thick setae, one of these on each anterior labral lobe much longer than the others, projecting ventrally; extreme base of ventral surface of mandible with very fine, long seta that curves forward and nearly touches ventrally projecting labral seta; each larger mandibular tooth with prominent fully appressed seta; anterior margin of scape with 6-7 stiff clavate setae, basalmost seta the longest, on apex of anterobasal lobe (lacking a shorter seta proximal to this one, on inner side of lobe); clypeus and face devoid of ground pilosity or with very sparse, fully appressed ground pilosity; 5-7 stout clavate seta irregularly distributed on facial arc; mesonotum, petiole and postpetiole lacking erect setae, ground pilosity extremely short, sparse, unnoticeable; mesotibia with short, thin, sparse, decumbent ground pilosity, a single large stout clavate seta and several thin shorter erect setae at apex; mesobasitarsus with 2 pairs long, thin, erect setae; first gastral tergite with 4 clavate setae on posterior margin, following exposed tergites each with row of clavate setae; ground pilosity of first gastral tergite short, sparse, fully appressed, somewhat more noticeable than on mesosoma; first gastral sternite with sparse, thin but stiff erect setae over much of surface except narrow area near postpetiolar insertion.

Color orange.

Queen. HW 0.51-0.63, HL 0.48-0.60, WL 0.68-0.85, CI 104-105 (n=2). Labrum, mandible, and scape similar to worker; anterior clypeal margin different from worker, with a broad semicircular concavity medially, flanked on each side by a smaller semicircular notch; clypeus smooth and shining with sparse puncta , separated from vertex with distinct suture; frontal carinae distinct, fading at about level of mid-length of compound eye; transverse facial arc feeble, marked by a semicircular row of10 erect clavate setae (5 setae on Colombia queen); face anterior to row of setae flat, irregularly rugose, with weak longitudinal median ruga (median ruga absent on Colombia queen), face rugosity extending posteriorly across facial arc, grading to smooth and shining with sparse puncta near occipital carina; ocelli distinct, anteromedian ocellus immediately anterior to seta row; compound eye large, multifaceted, about 12 ommatidia in longest row; antennal scrobe shallow, like worker.

Mesosoma with queen-typical alar sclerites; lateral and anterior pronotum with faint, minute punctatorugose sculpture, fading on sides; mesoscutum, axilla, and scutellum irregularly longitudinally rugulose; anepisternum and katepisternum separated by strong sulcus, both smooth and shining; metapleuron distinct, with shallow transverse sulcus, separated from side of propodeum by dorsoventral sulcus; metapleuron and side of propodeum matte; posterodorsal propodeum foveolate; propodeal spines pronounced, in the form of flattened perpendicular plates, acute; propodeal spiracle smaller and lower compared to worker, anterior to infradental propodeal lamella; mesoscutum with 10 erect clavate setae, scutellum with 2 (axilla also with seta on Colombia queen).

Petiole similar to worker, but posterior rim more pronounced and projecting; ventral margin of postpetiole with short right-angle tooth; first gastral tergite punctate over much of surface, grading to smooth and shining at posterior border; petiole and postpetiole lacking erect setae; first gastral tergite with 40-50 erect setae; first gastral sternite densely punctate, with abundant short, stiff, erect setae.

Color red.

Biology. The type series was collected at a site in the mountains of western Panama, presumably cloud forest (1550 m elevation), in "debris at base of stump." A worker was collected in forest floor leaf litter on Barro Colorado Island. The Colombia queen was collected in a forest litter Berlese sample, at a mid-elevation wet forest site (1000 m).

Etymology. The name refers to it being a southern version of O. convallis . It is a noun in apposition and thus invariant.