Claustropyga

Vilkamaa, Pekka & Hippa, Heikki, 2007, Review of the Nearctic Claustropyga Hippa, Vilkamaa & Mohrig (Diptera, Sciaridae) with the description of three new species, Zootaxa 1552, pp. 53-68 : 54-56

Key to the known species of Claustropyga

The key given by Hippa, Vilkamaa and Mohrig (2003) does not work perfectly and contains some shortcomings and mistakes. We take the opportunity here to give a new key which we hope will work better. When identifying Palaearctic species, the key should be used together with the illustrations given by Hippa, Vilkamaa and Mohrig (2003). A smoothly functioning and easy key to the species of Claustropyga is difficult to compile because some of the characters which are usually useful in identifying sciarids are variable within the species, such as the number of palpomeres and the number and position of the gonostylar megasetae.

1. Gonostylus nearly as broad as long, the ventral mesial margin drawn out into a large lobe which is nearly as broad as the body of the gonostylus ( Fig. 4 D, E), gonostylus with or without an apical tooth ............. 2

- Gonostylus much longer than broad, without a large ventral mesial lobe, but if a lobe is present it is narrow, at most one-fifth of the width of the body of the gonostylus, gonostylus with an apical tooth, (e.g. Figs 1 A–C, 2A, B and 2E, F)....................................................................................................................... 3

2. Gonostylus with an apical tooth and with a large megaseta mesially on the basal half which in ventral view is covered by the ventral mesial lobe, tegmen without a pair of finger-like prongs apically .............. ................................................................................................................. C. corticis (Mohrig & Antonowa)

- Gonostylus without an apical tooth ( Fig. 4 E) and without a mesial megaseta on the basal half, tegmen with a pair of long finger-like prongs posteriorly ( Fig. 4 E, D) ......................................... C. mirifica sp. n.

3. Tegmen unusually long, more than twice as long as wide at base (at base of the apodemes), the intercoxal lobe (sternite 9) unusually long, about two-thirds of the ventral length of gonocoxa .................................. ................................................................................................................................. C. clausa (Tuomikoski)

- Tegmen of usual length, as long as basally broad or shorter, intercoxal lobe about half of the ventral length of gonocoxa or shorter, or the intercoxal lobe missing................................................................................ 4

4. Gonostylus with a group of subapical megasetae laterally near the base of the apical tooth, these megasetae distinctly separated by a gap from the apical tooth and a megaseta at the extreme base of the tooth .... .......................................................................................................................... C. refrigerata (Lengersdorf)

- Gonostylus without subapical megasetae laterally near the base of the apical tooth and separated from it by a distinct gap, there may be one megaseta at the extreme base of the apical tooth ( Figs 3 C, D, 7E, D) 5

5. Number of megasetae on the mesial surface of the gonostylus 12 or more ................................................ 6

- Number of megasetae on the mesial surface of the gonostylus 10 or less................................................... 7

6. Intercoxal lobe lacking ..................................................................... C. janetscheki (Mohrig & Röschmann)

- Intercoxal lobe present, large and semicircular ( Fig. 6 E) ..................................................... C. spicea sp. n.

7. Gonostylus with a sharply demarcated flat apical part and convex basal part, the former about one-third of the gonostylar length and bearing the apical tooth and one to three variously placed megasetae, the convex

basal part of the gonostylus with unusually long setae which distinctly differ from the other ventral setosity ( Fig. 3 C, D)............................................................................. C. subcorticis (Mohrig & Krivosheina) - Gonostylus with an evenly convex ventral surface but if there is a flattened apical part it is small and inconspicuous, shorter than the apical tooth, the ventral setosity of gonostylus normal (e.g. Figs 1 A–D, 3A, B) ......................................................................................................................................................... 8

8. Ventral and lateral setae of the gonostylus short, as long as or shorter than the gonostylar megasetae and usually shorter than half the ventral width of gonostylus, not including the rather long setae near the apex and the mesial margin of gonostylus ( Fig. 2 F) ............................................................................................ 9

- Ventral and lateral setae of gonostylus long, at least some of the lateral setae as long as or longer than the gonostylar megasetae, the setae usually distinctly longer than half the ventral width of gonostylus (e.g. Fig. 3 A)...................................................................................................................................................... 11

9. Ventral and lateral setae of gonostylus very short, most of them only one-eighth the width of the gonostylus, gonostylar megasetae in two groups, one at the middle and the other subapical and apical, the groups separated by a gap which is about as long as the length of a megaseta ........................................................ .......................................................................................................... C. brevichaeta (Mohrig & Antonowa)

- Ventral and lateral setae of gonostylus longer, most of them at least one-third the width of the gonostylus, the gonostylar megasetae rather evenly distributed on the apical half of gonostylus, the longest gaps less than one-half the length of a megaseta ...................................................................................................... 10

10. Number of gonostylar megasetae 6 or 7, the apicolateral margin of tegmen, i.e. the margin between actual apex and the rounded lateral prominence, angularly convex .................................. C. abblanda (Freeman)

- Number of gonostylar megasetae 9 or 10, the apicolateral margin of tegmen roundly convex ( Fig. 2 E, F) ........................................................................................................... C. aperta Hippa, Vilkamaa & Mohrig

11. Tegmen with strong lateral shoulders ( Fig. 7 D) ........................................................................................ 12

- Tegmen without lateral shoulders, the lateral margin simple or with a rounded or acute lobe or tooth (e.g. Figs 1 B, C, 2A, E) ..................................................................................................................................... 13

12. All the gonostylar megasetae arising from normal sockets only, lateral shoulders of the tegmen strongly sclerotized and continuing apically transversely under the more apical and weakly sclerotized part of tegmen ................................................................................................... C. tumida Hippa, Vilkamaa & Mohrig

- One of the megasetae at the middle of gonostylus arising from a basal body which is as long as the megaseta, lateral shoulders of tegmen weakly sclerotized, its margin contiguous with the margin of the more apical part ( Fig. 7 D, E) .............................................................................................................. C. triloba sp. n.

13. Fore tibia subapically on the ventral half of the prolateral side with a transverse row of a few setae, the posterior margin of the intercoxal lobe of hypopygium strongly convex, nearly semicircular, tegmen with a prominent apicomedial lobe which is nearly parallel-sided and is as long as broad .................................. .................................................................................................. C. ctenophora Hippa, Vilkamaa & Mohrig

- Fore tibia subapically on the ventral half of the prolateral side with a patch of a few to many setae ( Fig. 5 B), the posterior margin of the intercoxal lobe of hypopygium transverse or convex, in the latter case not nearly semicircular ( Fig. 2 A), tegmen without a prominent apicomedial lobe or with a less prominent lobe which has slanted sides and which is shorter than broad, in C. sajanica with a prominent lobe which is long but is unusually narrow at apex and only ca. one-tenth of the width of tegmen ............................... 14

14. The longest gonostylar megasetae (without sockets) long, longer than the apical tooth and ca. one-half the width of gonostylus ( Figs 1 A–D, 2A, B)................................................................................................... 15

- The longest gonostylar megasetae (without sockets) short, shorter than or as long as the apical tooth and ca. one-third the width of gonostylus ( Figs 3 A, B, 5C, D) ...................................................................... 17

15. Gonostylus tumid, without a longer attenuated apical part which appears curved mesad, the gonostylus reaching half of its maximum width near the base of the apical tooth ( Fig. 2 A, B) .................................... ....................................................................................................... C. simplicis Hippa, Vilkamaa & Mohrig

- Gonostylus slender, with a long gradually attenuated apical part which appears curved mesad, the gonostylus reaching half its maximum width (at middle) far basad of the apex, at a distance equalling the length of the apical tooth or further basad ( Fig. 1 A–D) ............................................................................ 16

16. Basalmost megaseta of gonostylus well in its basal half ( Fig. 1 A, B) ......... C. acanthostyla (Tuomikoski)

- Basalmost megaseta of gonostylus well in its apical half ( Fig. 1 C, D) ........................................................ .................................................................................................. C. elizabethae Hippa, Vilkamaa & Mohrig

17. Intercoxal lobe of hypopygium, or the intercoxal area when the lobe is indistinct, with a medial non-setose stripe which is as wide as the diameter of three sockets of the adjacent setae (similar to Fig. 2 E) ......... 18

- Intercoxal lobe of hypopygium evenly setose, without a medial non-setose stripe ( Figs 3 A, 4C), ......... 19

18. Gonostylus with 7 or more megasetae, tegmen without or with a scarcely identifiable lateral tooth-like projection ......................................................................................................... C. heteroclausa (Rudzinski)

- Gonostylus with 4 megasetae, tegmen with prominent lateral tooth-like projections or subapical angles .. ................................................................................................................ C. sajanica (Mohrig & Antonowa)

19. Subapical prolateral patch of modified setae on fore tibia small, consisting of less than 10 setae arising from a roundish patch with a different cuticular structure, the mesial megasetae extending to the basal half of gonostylus ( Fig. 2 A, B) .......................................................... C. auriculata Hippa, Vilkamaa & Mohrig

- Subapical prolateral patch of modified setae on fore tibia large, consisting of more than 10 setae arising from an area without conspicuously different cuticular structure ( Fig. 5 B), all mesial megasetae in the apical half of gonostylus ( Fig. 5 C, D) ............................................. C. obtusidens Hippa, Vilkamaa & Mohrig

Figures

FIGURE 1. Part of hypopygium (A, C) and gonostylus (B, D) in ventral view. A and B: Claustropyga acanthostyla (Tuomikoski) (from Alaska). C and D: C. elizabethae Hippa, Vilkamaa & Mohrig (holotype from Alaska). Scale 0.10

FIGURE 2. Part of hypopygium (A, E) and gonostylus (B, F) in ventral view, and maxillary palpus in mesial (C) and in apico-dorsal (D) view. A and B: Claustropyga simplicis Hippa, Vilkamaa & Mohrig (from British Columbia). C – F: C. aperta Hippa, Vilkamaa & Mohrig (from British Columbia). Scale 0.10 mm.

FIGURE 3. Part of hypopygium (A, C) and gonostylus (B, D) in ventral view. A and B: Claustropyga auriculata Hippa, Vilkamaa & Mohrig (from Alaska). C and D: C. subcortici s Mohrig & Krivosheina (from Alaska). Scale 0.10 mm.

FIGURE 4. Claustropyga mirifica sp. n. (holotype): Antennal flagellomere 4 in ventral view (A), maxillary palpus in dorsal view (B), wing in dorsal view (C), part of hypopygium (D) and gonostylus (E) in ventral view. Scale 0.10 mm, in C 1.0 mm.

FIGURE 5. Claustropyga obtusidens Hippa, Vilkamaa & Mohrig (from Yukon). Maxillary palpus in dorsal view (A), apical part of fore tibia in prolateral view (B), part of hypopygium in ventral view (C) and gonostylus in ventral view (D). Scale 0.10 mm.

FIGURE 6. Claustropyga spicea sp. n. (holotype). Maxillary palpus in dorsal view (A), antennal flagellomere 4 in ventral view (B), apical part of fore tibia in prolateral view (C), apical part of hind tibia in retrolateral view (D), and part of hypopygium (E) and gonostylus (F) in ventral view. Scale 0.10 mm.

FIGURE 7. Claustropyga triloba sp. n. (holotype). Maxillary palpus in dorsal view (A), antennal flagellomeres 4 and 5 in ventral view (B), apical part of fore tibia in prolateral view (C), and part of hypopygium (D) and gonostylus (E) in ventral view. Scale 0.10 mm.