Prenolepis

Williams, Jason L., 2016, Taxonomic revision and phylogeny of the ant genus Prenolepis (Hymenoptera: Formicidae), Zootaxa 4200 (2), pp. 201-258 : 216

Key to the worker caste of extant Prenolepis species

1 In profile view, petiole narrow and elongate (PetWI <55) with a rounded dorsal apex of the scale ( Figs 51, 52, 54–56 ); in fullface view, torulae not touching the posterior border of clypeus ( Figs 39–41, 43, 44, 50 )..............................2

- In profile view, petiole short and broad (PetWI> 55) and forward-inclined with a sharply-angled dorsal apex of the scale ( Fig 53 ); in full-face view, torulae overlapping with the posterior border of clypeus ( Figs 38, 42, 45–49 )................... 7

2 Ocelli absent; compound eyes surpassing the lateral margins of head in full-face view; scapes with appressed setae.......3

- Three small ocelli present; compound eyes not surpassing the lateral margins of head in full-face view; scapes with erect setae....................................................................................................5

3 Small (TL <2.70mm), robust with short legs (HTI <150), antennae (SI <160), and mesosoma (BLI <175); body light to medium brown; in profile view, posterodorsal part of propodeum obtusely angled ( Fig 20 ); petiolar scale low in profile with a weakly sinuate anteroventral outline ( Fig 54 )....................................................... P. jacobsoni

- Medium to large (TL> 2.70mm), gracile with elongate legs (HTI> 185), antennae (SI> 175), and mesosoma (BLI> 175); body uniformly dark brown to black; posterodorsal part of propodeum in profile view roundly produced, much higher than pronotum ( Figs 21, 27 ); petiolar scale high in profile with a roughly subtriangular anterodorsal outline and almost straight ventral outline ( Figs 55, 56 )............................................................................... 4

4 Overall cuticle shiny and smooth to lightly reticulate; pubescence completely absent on the dorsal surface of pronotum, propodeum, or gaster................................................................................ P. jerdoni

- Overall cuticle dull and finely reticulate; thick patches of pubescence present on the dorsal surface of pronotum, propodeum, and gaster.................................................................................. P. subopaca

5 Body uniformly dark brown to black; head roughly subtriangular in shape; cuticle of head lightly reticulate; ectal surface of mandibles with light longitudinal striations; in profile view, the ventral surface of petiole almost straight ( Fig 55 ).. P. fisheri

- Head and mesosoma light brown in overall color; ectal surface of mandibles smooth and shiny; in profile view, the ventral surface of petiole is curved upward toward the anterior articulation with the metanotum ( Figs 51, 52 ).................... 6

6 Body light brown with little to no difference in color among head, mesosoma, and gaster; head roughly square in full-face view; cuticle of head lightly reticulate; in profile view, dorsal outline of petiolar scale roughly subtriangular in shape ( Fig 51 )............................................................................................. P. darlena

- Head and mesosoma light brown and gaster distinctly dark brown to black; head roughly subtriangular in full-face view; cuticle of head finely rugoreticulate; in profile view, petiole club-shaped with dorsal outline of petiolar scale rounded ( Fig 52 ).............................................................................................. P. fustinoda

7 In full-face view, compound eyes strongly convex, surpassing the lateral margins of head; anterior border of clypeus without a pair of prominent anterolateral lobes............................................................... P. naoroji

- In full-face view, compound eyes weakly convex and not surpassing the lateral margins of head; anterior border of clypeus with a pair of prominent anterolateral lobes ( Figs 38, 42, 45, 46, 48, 49 )......................................... 8

8 Large (TL> 4.25mm); in profile view, propodeum with a rounded dorsal face ( Fig 23 ); head and mesosoma yellow-brown, and gaster dark brown to black................................................................. P. melanogaster

- Small to medium (TL <4.25mm); in profile view, propodeum with a flat to softly rounded dorsal face, posterodorsally obtusely angled ( Figs 15, 19, 22, 25, 26 ).................................................................. 9

9 Scapes with erect setae; body dark brown, with a faint blue cuticular iridescence.......................... P. angularis

- Scapes with appressed setae; body light to dark brown, without a faint blue cuticular iridescence..................... 10

10 Compound eyes round in shape, medium-sized (distinctly smaller than those of other Prenolepis species); interocular distance relatively long (REL3 <35)..................................................................... P. mediops

- Compound eyes oval in shape, relatively large; interocular distance relatively short (REL3> 40)..................... 11

11 Ectal surface of mandibles smooth and shiny, without longitudinal striations; in profile view, border of mesonotum bulges and rises above pronotum ( Fig 26 )................................................................. P. shanialena

- Ectal surface of mandibles with deep longitudinal striations.................................................. 12

12 In profile view, mesosoma more robust at the mesonotal constriction ( Fig 25 ); distributed across southeastern Europe , the Balkan Peninsula, Turkey, and east to Georgia............................................................ P. nitens

- In profile view, mesosoma slender at the mesonotal constriction ( Fig 19 ); distributed across North America , from southern Canada to Mexico............................................................................. P. imparis

Figures

FIGURES 51 – 56. Illustrations of petiole shapes (profile view) observed in Prenolepis species. 51, P. darlena; 52, P. fustinoda; 53, P. imparis (typical shape seen in most Prenolepis species); 54, P. jacobsoni; 55, P. jerdoni; 56, P. subopaca.

FIGURES 38 – 50. Illustrations of clypeus shapes (full-face view) observed in all Prenolepis species. Apparent differences in width of torulae are artifacts of specimen orientation. In some species the torulae are oriented more laterally. 38, P. angularis; 39, P. darlena; 40, P. fisheri; 41, P. fustinoda; 42, P. imparis; 43, P. jacobsoni; 44, P. jerdoni; 45, P. mediops; 46, P. melanogaster; 47, P. naoroji; 48, P. nitens; 49, P. shanialena; 50, P. subopaca.

FIGURES 15 – 27. Illustrations of mesosoma shapes (profile view) observed in all Prenolepis species. 15, P. angularis; 16, P. darlena; 17, P. fisheri; 18, P. fustinoda; 19, P. imparis; 20, P. jacobsoni; 21, P. jerdoni; 22, P. mediops; 23, P. melanogaster; 24, P. naoroji; 25, P. nitens; 26, P. shanialena; 27, P. subopaca.