Key to Costa Rica Azteca queens

This worker key is based on: Longino, J.T. 2007. A taxonomic review of the genus Azteca in Costa Rica and a global revision of the aurita group. Zootaxa. 1491:1-63.

The queen of Azteca chartifex is unknown, but it will probably key to Azteca tonduzi.

There is a Key to Costa Rica Azteca workers but worker polymorphism and similarities of worker characteristics can make workers of Azteca difficult to use for species determinations. Queens of Azteca generally exhibit more pronounced morphological differences and are often much more useful than workers for species identification. Details of the nests collections are made from, e.g., location, structure, etc. can also be useful. Nesting details can be found on many of the species pages linked to from this key.

1

Longino 2007. Figure 2.

Outer margin of hind tibia with abundant erect setae, MTSC usually > 20, if MTSC in the 10–20 range, CI > 95 . . . . . 2

Outer margin of hind tibia with erect setae reduced to absent, MTSC < 20, if MTSC in the 10–20 range, CI < 80 . . . . . 11

2

Head subrectangular (Fig. 2, coeruleipennis, xanthochroa), CI < 90, obligate Cecropia inhabitant . . . . . 3

Head with sides more rounded (e.g., Fig. 2, constructor), CI > 90, nesting habits various . . . . . 4

3

Color dark brown to black, HW < 1.55mm; head shape as in Fig. 2 (coeruleipennis); palpal formula 6,4 . . . . . Azteca coeruleipennis

Color orange, HW > 1.80mm; head shape as in Fig. 2 (xanthochroa); palpal formula 5,3 . . . . . Azteca xanthochroa

4

Color solid black throughout; mesosomal dorsum with dense brush of setae over entire surface; many setae on margin of vertex as long as distance between lateral ocelli (Fig. 2, constructor); HW 1.4–1.8mm; palpal formula 5,3; obligate Cecropia inhabitant . . . . . Azteca constructor

Color rarely solid black, usually red brown, or black with lighter yellow brown on variable extent of anterior and lateral face; mesosomal dorsum often with abundant setae but never a dense brush; setae on margin of vertex shorter than distance between lateral ocelli; HW various; palpal formula 6,4; not obligate Cecropia inhabitants . . . . . 5

5

Longino 2007. Figure 1.

Longino 2007. Figure 5.

Longino 2007. Figure 3.

HW > 2.3mm; face usually uniformly colored light red brown to dark brown . . . . . 6

HW < 2.2mm; face with variable combination of black to lighter yellow brown (varies from almost entirely black with narrow region of lighter color at anterior margin of head capsule, to almost entirely yellow brown with patch of infuscation on posteromedian vertex) . . . . . 7

6

Antennae relatively long (SI > 58); ocelli large (OCW > 0.20mm); posterior sternal lobe of petiole shallow and evenly sloping to apex of posterior tergal lobe (Fig. 1E, 5); apex of petiolar node in lateral view flattened and scale-like (Fig. 5) . . . . . Azteca instabilis

Antennae relatively shorter (SI < 55); ocelli small (OCW < 0.15mm); posterior sternal lobe of petiole more convex and shorter, meeting posterior tergal lobe before apex (Fig. 1D, 5); apex of petiolar node acute but not as strongly flattened, more bluntly rounded (Fig. 5) . . . . . Azteca gnava

7

HW > 1.9mm; face extensively yellow brown with darker brown infuscation on vertex (Fig. 3) . . . . . Azteca sericeasur

HW < 1.9mm; face coloration as above or more extensively dark brown to black . . . . . 8

8

HW < 1.58mm; head almost entirely black, with small band of lighter coloration on anterior head capsule (Fig. 3) . . . . . Azteca flavigaster

HW > 1.58mm; head coloration as above or with more extensive yellow coloration extending up sides of head and into antennal fossae . . . . . 9

9

Sternal lobe of petiole with posterior margin forming a separate convexity that extends as far posteriorly as posterior tergal lobe, with a small notch or concavity between the sternal convexity and the tergal lobe (Fig. 1D, 5); head relatively short; forms ant gardens. . . . . Azteca nigra

Sternal lobe of petiole evenly curved to tergosternal suture, not forming separate convexity or notch, posterior tergal lobe extending further posteriorly than sternal lobe (Fig. 1E); head relatively longer (velox, quadraticeps); nests in live or dead stems with variable construction of small carton shelters, but not forming large conspicuous ant gardens . . . . . 10

10

Head relatively shorter and more cordate, sides more strongly narrowing anteriorly (Fig. 3) . . . . . Azteca velox

Head relatively longer and more quadrate, sides less strongly narrowing anteriorly (Fig. 3) . . . . . . Azteca quadraticeps

11

Meso- and metatibial spurs absent; anterior margin of clypeus strongly convex, median lobe extending anterad to lateral lobes (HLB/HLA > 1.04); entire body smooth and shiny, highly polished (aurita group) . . . . . 12

Meso- and metatibia with distinct pectinate spurs; anterior margin of clypeus weakly convex, subparallel with lateral lobes (HLB/HLA <1.01); body surface duller, not shiny . . . . . 14

12

Color yellow-orange; posterolateral margins of vertex forming pronounced triangular lobes (Fig. 2); CI > 85 . . . . . Azteca pilosula

Color brown; posterolateral margins of vertex not forming pronounced triangular lobes; CI < 80 . . . . . 13

13

HW < 0.65mm; sides of head relatively more rounded and converging toward posterolateral lobes of vertex; outer surface of metatibia with abundant suberect pubescence and numerous, regularly spaced, short, erect setae . . . . . Azteca nanogyna

HW > 1.00mm; sides of head subparallel, not converging toward posterolateral lobes of vertex (Fig. 2); outer surface of metatibia with pubescence relatively short, sparse, appressed, and inconspicuous; outer surface of metatibia lacking erect setae or with a few, irregularly spaced, short setae near the base . . . . . Azteca schimperi

14

Head relatively short and broad (CI > 78) . . . . . 15

Head relatively long and narrow, subrectangular (CI < 78) . . . . . 18

15

Petiolar node strongly flattened, scale-like (Fig. 5); head short and broad (CI > 100) . . . . . Azteca tonduzi

Petiolar node not strongly flattened, apex usually bluntly rounded; head relatively longer and thinner (CI < 90) . . . . . 16

16

HW > 1.53mm; dorsal surface of mandible evenly covered with abundant large piligerous puncta (Fig. 1G), setae arising from puncta erect, about as long as width of mandibular teeth; builds carton galleries on tree trunks, not a Cecropia specialist . . . . . Azteca forelii

HW < 1.45; much of dorsal surface of mandible with sparse, small puncta bearing setae that are reduced to short remnants, no longer than width of puncta (Fig. 1F), puncta with longer setae restricted to apex and near masticatory margin; Cecropia specialists . . . . . 17

17

Fourth abdominal tergum with < 6 erect setae, exclusive of posterior row; dorsal surface of head, when viewed in profile, with setae occurring in three clusters separated by distinct gaps, one cluster on and just above the clypeus, one around the ocelli (these may be entirely absent), and one on the upper vertex; scape relatively short (SI 45–49); color usually black . . . . . Azteca alfari

Fourth abdominal tergum with > 10 erect setae (rarely fewer), exclusive of posterior row; dorsal surface of head, when viewed in profile, often with setae bridging the gap between the ocellar region and the upper vertex, and often with setae extending up from the clypeus almost to the ocellar region; scape relatively longer (SI 49–54); color black to lighter red brown . . . . . Azteca ovaticeps

18

Color largely orange; HW > 1.2mm . . . . . Azteca beltii

Color largely or entirely black; HW < 1.2mm . . . . . 19

19

Mandible with even covering of coarse, piligerous puncta; mandible surface appearing bristly . . . . . 20

Mandible with row of piligerous puncta along masticatory margin, but large puncta sparse to absent on mandible surface proximal to this row, and with at most four puncta bearing setae . . . . . 21

20

Scape relatively short (SI 39–43) . . . . . Azteca brevis

Scape longer (SI 50–52) . . . . . Azteca nigricans

21

Head strongly rectangular, with flat sides and posterolateral lobes of vertex relatively angular; head relatively longer and narrower (SI < 63) . . . . . 22

Head less rectangular, with sides slightly convex, and lateral margin of vertex more broadly rounded; head relatively shorter and wider (SI > 63) . . . . . Azteca pittieri

22

Petiolar node low, anterior face of petiole flat (Fig. 5); metatibia with few erect setae (MTSC < 5); propodeum with sparse short setae concentrated posterior to spiracle; mandible lacking large puncta proximal to masticatory margin; size relatively large (HW > 0.92mm) . . . . . Azteca oecocordia

Petiolar node higher, anterior face somewhat concave (Fig. 5); metatibia with relatively more setae (MTSC 10–20); propodeum with setae sparse or abundant; mandible with about 5 large puncta proximal to masticatory margin; size relatively smaller (HW < 0.93mm) . . . . . Azteca longiceps