Polistes (Fuscopolistes)

Buck, Matthias, Cobb, Tyler P., Stahlhut, Julie K. & Hanner, Robert H., 2012, Unravelling cryptic species diversity in eastern Nearctic paper wasps, Polistes (Fuscopolistes), using male genitalia, morphometrics and DNA barcoding, with descriptions of two new species (Hymenoptera: Vespidae), Zootaxa 3502, pp. 1-48 : 23-25

Key to eastern Nearctic species of Polistes (Fuscopolistes)

The following key is a revised, adapted version of the key to Polistes by Buck et al. (2008). The two new species were treated in that paper as "sp. A" ( P. hirsuticornis ) and "sp. B" (P. p a r a m e t r i c u s). The area covered by the key includes eastern Canada and the eastern United States (from the Atlantic to the western boundary of Minnesota, Iowa, Missouri, Arkansas and Louisiana). There are no other species of Polistes outside the geographic range of this key that could be confused with P. hirsuticornis and P. p a r a m e t r i c u s.

1. Micropunctures of mesosoma and female clypeus smaller than in other species (separated by approximately their own diameter on mesopleuron), the integument therefore more shining, with a ‘greasy’ lustre (IAV Fig. B10.14). Eye with scattered, minute hairs (length ca. 15 μm, visible at 20 × magnification). Pronotal fovea either absent (IAV Fig. B10.14) or developed as a minute, shallow pit, in males rarely well developed ( Table 1 ). Propodeal orifice distinctly and fairly abruptly narrowed dorsally (IAV Fig. B10.16). Female: flagellomeres 1–8 or 9 with relatively long, bristly hairs posteriorly and dorsally (length ca. 60 μm, hairs becoming sparser and shorter on distal flagellomeres; IAV Fig. B10.18) ( U.S.: NY to FL, west to IL, MO; distribution insufficiently known)........................................................... P. hirsuticornis Buck , sp. nov.

- Micropunctures of mesosoma and female clypeus coarser (separated by approximately half their own diameter on mesopleuron), the integument less shining, without ‘greasy’ lustre (e.g., IAV Fig. B10.15). Eye usually bare; hairs, if present, extremely sparse and only visible at higher magnification. Pronotal fovea usually well developed, penetrating pronotum (IAV Fig. B10.15); minute and shallow in malformed specimens only. Propodeal orifice at most slightly and gradually narrowed dorsally (IAV Fig. B10.17), except sometimes in P. parametricus sp.n. Female flagellum with bristly hairs absent or short (≤ 30 μm), if present restricted to flagellomeres 1–2 (IAV Fig. B10.19) or 1–6 in P. rubiginosus (which can be distinguished by the entirely pubescent gena, cf. couplet 5; IAV Fig. B10.20)............................................................. 2

2. Female (six metasomal segments)......................................................................... 3

- Male (seven metasomal segments)...................................................................... 12

3. Metasoma without yellow markings, or only tergum 1 with yellow apical fascia (IAV Figs B10.48–49, B10.52–54, B10.56)...................................................................................................... 4

- Metasoma with yellow markings on tergum 1 and at least one of segments 2–6 (IAV Figs B10.47, B10.50–51, B10.55, B10.57).................................................................................................... 9

4. Mesosoma, metasoma, and legs almost entirely ferruginous (IAV Figs B10.48–49, C72.1, C72.3, C79.1, C79.3), black or dark brown areas, if present, restricted to one or more of the following areas: small spot in front of pronotal carina, certain sutures of mesosoma, margins and sometimes one or three longitudinal stripes on scutum, median groove of propodeum, narrow bases of terga 2 or 3 (rarely), posterior bases of coxae, and apex of hind tibia medially...................................... 5

- At least either mesosoma, metasoma or legs with more extensive black areas than above............................. 6

5. Malar space and gena uniformly covered by fine, appressed silvery pubescence arising from minute punctures, interspersed by a few scattered macrosetae arising from larger punctures (IAV Fig. B10.20). Propodeum coarsely ridged (IAV Fig. B10.37) ( U.S.: from IL and MD southward).................................................... P. rubiginosus Lepeletier

- Malar space and lower gena bare except for a few scattered macrosetae arising from larger punctures; only upper 3/4 of gena with fine, appressed silvery pubescence (IAV Fig. B10.21). Propodeum usually with fine or no ridging (IAV Fig. B10.38) ( U.S.: from VA southward, adventitious further north)........................................ P. carolina -complex* * Note: As demonstrated by male genitalia and molecular data (see below) P. carolina in its traditional definition includes at least two species. Some extreme colour forms of P. fuscatus from Gulf Coast states will also key here.

6. One or more of the following features present: clypeal disc marked with black; mesopleuron with yellow dorsal spot (IAV Fig. B10.28); at least one of metasomal segments 3–6 with ferruginous markings (southern Canada from ON to NB, eastern U.S.).............................................................................. P. fuscatus (Fabricius) , part.

- Clypeal disc entirely ferruginous (IAV Fig. B10.24). Mesopleuron lacking yellow dorsal spot. Metasomal segments 3–6 entirely black or dark brown (IAV Figs B10.52–54)........................................................... 7

7. Sternum 2 strongly convex (IAV Fig. B10.22). Black ocellar spot (if present) either separate from (IAV Fig. B10.24), or in rare cases, very narrowly connected to black antennal spot(s) (if present). Mesopleuron and propodeum with ferruginous marks (ON: Pelee I.; eastern U.S. from NY and IL southward)........................................... P. metricus Say

- Sternum 2 moderately convex (IAV Fig. B10.23). Black ocellar marking usually broadly connected to black antennal marking (IAV Fig. B10.25). Mesopleuron and/or propodeum of some specimens entirely black.............................. 8

8. Malar space short (UID/MS = 3.62–4.68). Sterna 3–5 densely, finely and regularly punctate (except sometimes near anterior margin where punctation becomes coarser), punctures less than one diameter apart (IAV Fig. B10.39); macropunctures regularly distributed and far less numerous than micropunctures. Scape 3.35–3.69 × as long as wide, gena 0.67–0.92 × eye width*. Mesopleuron sometimes entirely black............................................... P. fuscatus (Fabricius) , part.

- Malar space long (UID/MS = 2.83–3.43). Sterna 3–5 more coarsely punctate (except lateral and posterior margins and rarely narrow median strip) (IAV Fig. B10.40); punctures usually more spaced (i.e., in some areas two puncture diameters or more apart); punctures in some areas also more or less unevenly distributed, with macropunctures more numerous (their number equal to greater than number of micropunctures). Scape 3.15–3.43 × as long as wide, gena (0.80–)0.87–1.21 × eye width*. Mesopleuron at least with ferruginous dorsal spot (PA to NC and KY, west to MO; distribution insufficiently known)................................................................................... P. parametricus Buck , sp. nov. *Genal width measured as maximum distance between eye margin and occipital carina. Requires careful measurement in exact lateral view (see Material and methods).

9. Hind trochanter beyond basal constriction, and usually hind femur, with more or less developed black or brown markings...................................................................................................... 10

- Hind trochanter beyond basal constriction (and hind femur) ferruginous, without black or brown markings............. 11

10. Small species (fore wing length 10–13 mm). Hind femur with black or brown mark forming a complete ring near base (except many specimens from Gulf Coast states west of Florida). Clypeal disc without black or dark brown markings, usually with a yellow chevron-shaped ventral mark continued along inner eye margins (IAV Fig. B10.29). Black frontal markings, if present, not connecting ocelli to antennal sockets (IAV Fig. B10.29). Scape slightly shorter (UID/SL = 1.09–1.17) ( U.S.: southern and eastern U.S., east of Appalachians north to PA)............................................. P. dorsalis (Fabricius)

- Larger species (fore wing length 13–17 mm, exceptionally as short as 11 mm). Hind femur with black or brown mark often interrupted dorsally, if forming a complete ring then clypeal disc marked with black or dark brown, and black frontal marking connecting ocelli to antennal sockets (IAV Fig. B10.25). Scape slightly longer (UID/SL = 0.98–1.10)................................................................................................. P. fuscatus (Fabricius) , part.

11. Clypeus with at least half of disc yellow (IAV Fig. B1.11) (southern and eastern U.S., east of Appalachians north to Long Island, NY).......................................................................... P. bellicosus Cresson

- Clypeus with yellow markings, if present, occupying less than half of disc (IAV Fig. B10.25)... P. fuscatus (Fabricius) , part. Note: extreme colour forms of P. f u s c a t u s may intergrade with P. bellicosus , and are impossible to identify based on colouration or morphology.

12. Sternum 7 with prominent median tubercle, clearly visible in profile (IAV Fig. B10.31). All flagellomeres with tyloids dull orange-yellow; basal 2/5 of flagellomere 11 nearly parallel-sided in posterior view (IAV Fig. B10.32). [Anterior and ventral surfaces of flagellum concolorous yellow to orange from base to apex (as in IAV Fig. B10.36)]....... P. dorsalis (Fabricius)

- Sternum 7 with weak median tubercle, not visible in profile. Apical flagellomeres with tyloids shining black, brown, or orangeyellow; flagellomere 11 often more or less strongly tapered apically (IAV Fig. B10.33)............................. 13

13. Flagellum with anterior surface yellow to reddish brown basally, dark brown to black distally (IAV Figs B10.34–35).... 14

- Flagellum with anterior surface concolorous yellow, orange-yellow or reddish brown, at most slightly darker distally (IAV Fig. B10.36)............................................................................................ 15

14. Flagellomere 10 0.71–0.82 × as wide as flagellomere 1. Flagellomeres 1–5 with anterior surface dull yellowish to reddish brown (IAV Fig. B10.35). Aedeagal teeth small; each row of teeth stopping well before apex of median expansion of aedeagus ( Figs 54 , 62 , 66 ). Metasomal terga largely black, with ferruginous markings, if present, restricted to segments 1 and 2; whitish apical fascia usually only present on tergum 1, rarely on tergum 2 (exceptionally vestigial on 3).................................................................................... P. parametricus Buck , sp. nov. (typical specimens)

- Flagellomere 10 0.85–0.97 × as wide as flagellomere 1. Flagellomeres 1–5 with anterior surface bright yellow to orange (IAV Fig. B10.34). Aedeagal teeth large; each row of teeth extending basally almost to apex of median expansion of aedeagus ( Figs 50 , 58 , 63 ). Metasomal terga almost always with either ferruginous markings or pale apical fasciae more extensive than above................................................................................... P. fuscatus (Fabricius)

15. Metasoma with ferruginous markings, if present, restricted to terga 1 and 2....................................... 16

- Metasoma with ferruginous markings on all terga (sometimes very small on terga 1, 3 and 4)........................ 17

16. Aedeagus stout, AL/MPW = 5.0–6.0 ( Fig. 59 ). Scape 3.17–3.76 × as long as wide; UID/FI = 0.82–0.99*. Fore wing length 14.5–18.0 mm. Anterior surface of flagellum usually bright yellow or orange-yellow, at least basally, occasionally dull reddish. Ventral 2/3 of clypeus often slightly depressed medially. Tergum 1 usually without pale apical fascia, if present yellow to cream white............................................................................. P. metricus Say

- Aedeagus slender, AL/MPW = 8.0–10.0 ( Fig. 62 ). Scape 3.00–3.56 × as long as wide; UID/FI = 0.91–1.10. Fore wing length 12.0–16.0 mm. Anterior surface of flagellum darker, dull reddish. Ventral 2/3 of clypeus flat to slightly convex. Tergum 1 almost always with at least traces of a cream white apical fascia........ P. parametricus Buck , sp. nov. (atypical specimens) * The unusually great range of variation indicates the possibility of unrecognized cryptic species.

17. At least metasomal terga 1–3 with yellow apical fasciae (usually terga 1–4, with incomplete fascia on 5). Upper mesopleuron with yellow spot below pronotal lobe (similar to IAV Fig. B10.28)............................... P. bellicosus Cresson

- At most metasomal tergum 1 with yellow apical fascia. Upper mesopleuron almost always without yellow spot below pronotal lobe, if rarely present, the spot ill-defined................................................................. 18

18. Mesosoma with black markings reduced to nearly absent: scutum largely ferruginous, at most with narrow black borders and black admedian/parapsidal lines, i.e., ferruginous area never divided into discrete stripes. Tyloids of distal flagellomeres with large, smooth, shining central area (this area usually larger than mid ocellus). Propodeum usually smooth or with very fine transverse ridging (IAV Fig. B10.38), exceptionally with coarser ridging........................ P. c a ro li n a -complex*

- Mesosoma with more developed black markings: scutum usually predominantly black (sometimes entirely), typically with ferruginous stripes (one or two pairs, if with two then long median pair sometimes broadly confluent posteriorly but always well separated from short lateral pair, IAV Fig. C79.3). Tyloids of distal flagellomeres with smooth area smaller (sometimes nearly absent), dull to subshining. Propodeum usually with coarse transverse ridging (IAV Fig. B10.37)... P. rubiginosus Lepeletier * Note: As demonstrated by male genitalia and molecular data (see below) P. carolina in its traditional definition includes at least two species.

Figures

FIGURES 47 – 54. Apex of aedeagus, left lateral view: 47. Polistes bellicosus (MD, Worcester Co.), 48. P. carolina (TX, Bastrop Co.), 49. P. dorsalis (MD, Anne Arundel Co.), 50. P. f u s c a t u s (MD, Anne Arundel Co.), 51. P. metricus (MD, Anne Arundel Co.), 52. P. rubiginosus (MO, Callaway Co.), 53. P. hirsuticornis sp. nov. (MD, Anne Arundel Co.), 54. P. parametricus sp. nov. (MD, Prince George's Co.).

FIGURES 55 – 62. Apex of aedeagus, ventral view: 55. Polistes bellicosus (MD, Anne Arundel Co.), 56. P. carolina (TX, Bastrop Co.), 57. P. dorsalis (MD, Anne Arundel Co.), 58. P. f u s c a t u s (MD, Anne Arundel Co.), 59. P. metricus (FL, Highlands Co.), 60. P. rubiginosus (MO, Callaway Co.), 61. P. hirsuticornis sp. nov. (MD, Anne Arundel Co.), 62. P. parametricus sp. nov. (MD, Prince George's Co.). med ex: median expansion; pe val: penis valve. Arrows indicate the end of the row of aedeagal teeth.

FIGURES 63 – 66. Median expansion of aedeagus, ventrolateral view: 63. Polistes fuscatus (MD, Anne Arundel Co.), 64. P. metricus (MD, Anne Arundel Co.), 65. P. hirsuticornis sp. nov. (MD, Anne Arundel Co.), 66. P. parametricus sp. nov. (MD, Prince George's Co.).