Colobostema, Enderlein, 1926

Jean-Paul Haenni, 2013, A revision of the West Palaearctic species of Colobostema Enderlein, 1926 (Diptera, Scatopsidae). Part I. European subregion, Mitteilungen Der Schweizerischen Entomologischen Gesellschaft 86, pp. 199-242 : 238-239

publication ID

https://doi.org/ 10.5169/seals-403072

DOI

https://doi.org/10.5281/zenodo.6157689

persistent identifier

https://treatment.plazi.org/id/0A78FC5B-2261-5829-C59D-061CFB0BFAC8

treatment provided by

Plazi

scientific name

Colobostema
status

 

A SIMPLIFIED KEY TO EUROPEAN COLOBOSTEMA View in CoL View at ENA (males only, exclusive of the Mediterranean region)

A complete key to the West Palaearctic species of the genus will be provided in the second part of this revision. The simplified key below, essentially based upon characters of the male genitalia and of the pregenital segment, allows the identification of the temperate and boreal European representatives of the genus that are dealt with in the first part. Great care should be exercised regarding the shape of tergite 7, the appearance of which varies considerably according to the angle of view. Furthermore, it may be markedly distorted in dried specimens. To ensure a safe identification, it is highly advisable to cut and clear the tip of abdomen in potash.

1. Tergite 7 very short, about 3 times as wide as long ( Fig. 10 View Fig A); gonocoxites broadly truncate apically (Fig. IOC) .............................. C. schertenleibi View in CoL sp. n.

— Tergite 7 longer, as long as wide, or at most twice as wide as long; gonocoxites never broadly truncate apically...........................................................................2

2. Posterior margin of tergite 7 deeply emarginate ( Fig. 9 View Fig A); gonocoxites large, gradually narrowing towards apex ( Fig. 9 View Fig C).... C. obscuritarse (Strobl)

— Tergite 7 variously produced posteriorly or at most only slightly emarginate on posterior margin.............................................................................................3

3. Apical lobes of epandrium rounded ( Fig. 4 View Fig. 4 D); posterior margin of tergite 7 sinuous or shallowly emarginate ( Fig. 4 View Fig. 4 A) ............................... C. geigeri View in CoL sp. n.

— Apical lobes of epandrium acute; posterior margin of tergite 7 differently shaped ................................................................................................................. 4

4. Posterior margin of tergite 7 with 4 lobes, the submedian pair slightly asymmetrical, not much more developed than lateral pair ( Fig. 2 View Fig. 2 A); gonocoxites bearing an acute inner basal process ( Fig. 2 View Fig. 2 C).... C. dudai Krivosheina View in CoL

— At most 3 projections on posterior margin of tergite 7, median one usually much more developed than lateral ones, or tergite 7 nearly square or roughly pentagonal in shape.............................................................................................5

5. Gonocoxites massive, apically not narrowed ( Fig. 3 View Fig. 3 C); tergite 7 with a broadly triangular median projection on posterior margin ( Fig. 3 View Fig. 3 A) ......................... ................................................................................... C. flavimanum (Strobl) View in CoL

— Gonocoxites more slender, broadly triangular, always narrowing towards apex .................................................................................................................. 6

6. Tergite 7 roughly square or pentagonal, or posterior margin produced into a broad, practically straight median projection ( Figs 1 View Fig. 1 A-B, 11 A) ...................... 7

— Posterior margin of tergite 7 produced into a narrow elongate median projection, which is rounded or narrowly truncate apically, surrounded by a pair of much shorter, more or less developed lateral projections ( Figs 5 View Fig. 5 A, 6A, 7A, 8A)..................................................................................................................8

7. Tergite 7 pentagonal or square, with a short rounded median posterior projection (shape varying according to angle of view) ( Figs 1 View Fig. 1 A-B); epandrium with slightly asymmetrical apical lobes, which are comparatively longer and acute (Fig. IE) .......................................................................... C. auberti View in CoL sp. n.

— Posterior margin of tergite 7 with a broad, truncate median projection ( Fig. 11 View Fig. 11 A); epandrium with symmetrical short and blunt apical lobes ( Fig. 11 View Fig. 11 D) ...................................................................................... C. triste (Zetterstedt) View in CoL

8. Epandrium strongly asymmetrical apically, with one lobe much more developed than the other ( Fig. 6 View Fig. 6 D); sternite 7 deeply emarginate posteriorly, with strongly developed lateral projections ( Fig. 6 View Fig. 6 B) ..................... C. infumatum (Haliday)

— Epandrium with apical lobes symmetrical or only weakly asymmetrical; sternite 7 only weakly emarginate posteriorly ........................................................ 9

9. Epandrium with very acute, horn-like apical projections, which are directed posteriorly more or less obliquely ( Fig. 5 View Fig. 5 D) .................. C. griseinerve (Duda)

— Epandrium with apical lobes acute, directed laterally ( Figs 7 View Fig. 7 D, 8D).... 10

10. Median projection of posterior margin of tergite 7 rounded apically ( Fig. 8 View Fig. 8 A); gonocoxites strongly narrowed in distal half, with apex appearing blunt in ventral view ( Fig. 8 View Fig. 8 C); aedeagus short ( Fig. 8 View Fig. 8 C).... C. nigripenne (Meigen) View in CoL

— Median projection of posterior margin of tergite 7 clearly truncate apically ( Fig. 7 View Fig. 7 A); gonocoxites less strikingly narrowed in distal part, with apex acute ( Fig. 7 View Fig. 7 C); aedeagus elongate ( Fig. 7 View Fig. 7 C) ................................. C. lastovkai View in CoL sp. n.

Kingdom

Animalia

Phylum

Arthropoda

Class

Insecta

Order

Diptera

Family

Scatopsidae

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