Pyramica heterodonta, Rigato & Scupola, 2008

Pyramica heterodonta n. sp.

(figs. 4-6)

Holotype worker. TL 2.8, HW 0.50, HL 0.66, CI 76, ML 0.41, MI 62, SL 0.41, SI 82, PW 0.35, AL 0.74.

Mandibles relatively long and narrow with 4 preapical teeth and denticles. The largest tooth is placed at the apical third of the mandible. Apical fork with two intercalary denticles. Labral lobes well developed but distinctly shorter than trigger hairs. Anterior clypeal border convex medially. Antennal scrobe moderately impressed. Postoral transverse groove visible in profile but not very deep. Pronotum anteriorly delimited by a transverse carina marking a step above the cervical shield. Alitrunk in profile with a weakly convex promesonotum; mesonotum sloping very gradually to the nearly flat base of the propodeum. Mesonotum laterally bordered by a weak carina. Metanotal impression absent.

Propodeal teeth strong; their posterior edges form a lamella bordering the propodeal declivity. Petiole with a dome-like node, slightly convex above and posteriorly delimited by a transverse lamella just before the insertion of the postpetiole. Postpetiole much wider than petiole; in profile slightly lower and weakly convex above. The postpetiolar tergite bears anteriorly a transverse spongiform carina and posteriorly a transverse spongiform lamella at the insertion of the gaster; this lamella laterally widens and becomes lobiform. Postpetiolar sternite with a well developed spongiform appendage, which is subtriangular in profile.

Gaster anteriorly with a transverse spongiform thin lamella fitting that of the postpetiolar tergite.

Sculpture. Head, alitrunk and waist mostly densely reticulate-punctate; meso- and metapleuron chiefly smooth and shining. Postpetiolar disc weakly sculptured, superficially reticulate-punctate and anteriorly extensively smooth and shining. Gaster smooth with very short longitudinal costulae basally.

Pilosit y. Main erect setae on the body long and slightly clavate (remiform) and with the following arrangement: a pair apicoscrobal, two pairs on head dorsum (one on the vertex and one on the occiput), a humeral pair, a pair anteriorly on mesonotum; two pairs on the petiolar node; 8 hairs on the postpetiole arranged in two transverse rows. Gastral tergites bear several regularly arranged hairs. Ground pilosity (pubescence) sparse and slightly raised on head and alitrunk, a little more abundant on the appendages, including mandibles. Gastral sternites apically with long simple hairs, proximally the first sternite bears the usual transverse fringe of curled hairs. Anterior clypeal border fringed with spatulate hairs. Leading edge of scape with several standing, curved, simple to weakly spatulate hairs: the first two and the apical ones are bent toward the apex of the scape, setae 3 and/or 4 are bent toward the base.

Colour. Concolorous testaceous.

Paratype workers. TL 2.8-3, HW 0.49-0.51, HL 0.64- 0.67, CI 75-78, ML 0.40-0.42, MI 61-64, SL 0.39-0.42, SI 78-84, PW 0.33-0.35, AL 0.71-0.75 (7 measured).

The preapical mandibular dentition is variable: minute denticles may either miss or be even more abundant. I could count 3 to 5 preapical teeth and denticles, but the most usual number is 4 on both mandibles. The two largest teeth are always present, although the minor apicalmost one can be quite reduced; also, any denticle between those two teeth often misses and basalmost denticles are usually 1 or 2, but they can be so minute to be hardly visible. Another variable character is the sculpture of the postpetiolar disc, which usually is mostly smooth and shining; yet a weakly reticulate-punctate sculpture can be moderately developed. The inclination of setae on the scape is somewhat consistent with at least one hair (usually n°4 from the base) curved toward the base.

Holotype worker: ECUADOR, Pichincha, Pasochoa , 2940 m, 0°25’19” S – 78°30’57” W, 26.VII.2006, leg. G. Caoduro, A. Scupola, under bark [ MSNV] GoogleMaps

Paratypes ( 7 workers): same data as the holotype [ ASPC, MSNV, MSNM, QCAZ] GoogleMaps .

Etymology

From the Greek héteros, different, and odoús, odóntos, tooth, for its four mandibular preapical teeth and denticles all different in size from one another.

Comment

Another species in the gundlachi -complex (see “Comment” under P. osellai ). Its preapical dentition easily separates this species from its close relatives. Using Bolton’s revision it might be even keyed out with some difficulties either as P. jamaicensis or even as P. gundlachi ; yet both are distinctly smaller and the former much darker too (see also “N.B.” after the “Updating of the key to the Neotropical Pyramica ”).

Discussion

P. osellai and P. heterodonta seem very closely related: the main difference between them is the preapical mandibular dentition. P. osellai bears a higher number of elements, with two large ones and a definitely smaller one very close to the apicodorsal tooth; P. heterodonta has just one large tooth on its mandibular shaft. Yet general morphology, pilosity, sculpture, development of spongiform appendages on waist, measurements and indices are highly comparable. They cannot be easily assigned to any species clusters within the gundlachi -complex as defined by Bolton (2000); yet in many respects they look close to P. gundlachi itself. About the position of their intercalary denticles in the apical fork one may wonder whether they “belong” to the apicodorsal tooth. As apical teeth form an angle between themselves, rather than a curved surface, the intercalary denticles seem to stem from the base of the apicodorsal one. Our SEM pictures show a difference in colour (due to the presence of some metal as usual in the mandibular teeth of insects) that would suggest that intercalary denticles arise from the space between apical teeth.

Comparing both new species with gundlachi cluster they have a preapical dentition formed by alternatively large teeth and small denticles. In P. gundlachi and its relatives preapical dentition is formed by a series of quite similar denticles looking not as variable as in P. osellai and P. heterodonta . Also, postpetiolar disc is not strongly reticulate-punctate as in P. gundlachi and allies.

P. osellai cluster could be defined as follows:

1: mandibles of moderate length, MI 61-64, their inner margin weakly convex in their proximal half and slightly concave in the distal one;

2: two intercalary denticles arising from the space between apical mandibular teeth;

3: preapical dentition formed by 3 to 7 teeth and denticles placed in the distal two third or half of the mandibular shaft. These are strongly heteromorph with alternation of very small and large ones;

4: main pilosity formed by several pairs of elon-gate, somewhat remiform, hairs: apicoscrobal, 2 pairs on the head dorsum, humeral hairs, one pair on the anterior mesonotum. Leading edge of scape with simple to narrowly spatulate curved hairs;

Pṷramica

5: postpetiolar disc smooth to weakly reticulate-punctate.