Apetaenus, Eaton, 1875

Munari, Lorenzo, 2007, Studies on the Canacidae (Diptera), subfamily Apetaeninae. I. Apetaenus enderleini, nomen novum for Listriomastax litorea Enderlein, 1909, with remarks on the chaetotaxy, morphology, and habitats of the Apetaeninae from the Kerguelen Biogeographical Province, Zootaxa 1542 (1), pp. 21-34 : 24

Key to the species of Apetaenus from the Kerguelen Biogeographical Province

1. Strongly bristly flies, with thorax and abdomen shaggy, bearing several long, often wavy and tuft-forming, setae and setulae ( fig. 12 ). Strictly micropterous species showing squamiform wings ( figs. 9 and 12 ). Head markedly setulose, often with supranumerary setae and setulae. Postocellar setae variable, generally lacking, if present strongly cruciate; seta of postpronotal lobe variable, generally lacking, if present long and strong or, otherwise, very short and hairlike; dorsocentrals 1+2; 1 postalar, rarely 2. Setulae of mesonotum markedly long. Pleurae noticeably bristly, with numerous long and distinctly wavy setae; anepisternal setae long, often wavy, and numerous; katepisternum generally bearing 2–4 long setae on upper part. Forefemur with at most 1–2 postero-ventral setae on proximal third. Tarsi short and stumpy, with basitarsomeres about as long as tarsomeres 2–4 together. Female abdomen with syntergite 1+2 unbroken – not fissured medially ( fig. 14 ) –, only more or less slightly desclerotized on median, longitudinal line; posterior edge of tergite 1 still slightly recognizable dorsally, but distinctly separated from tergite 2 ventro-laterally; tergite 2 noticeably shorter than tergite 1, bearing several, short, scattered, spinelike setae on latero-ventral portion; tergite 3 undivided (in fig. 15 , after Séguy, 1940, it would appear divided medially), at times slightly desclerotized medially; all sternites present. Male terminalia with ventral epandrial lobe strongly pointed and curved inwards, bearing few long setae ( figs. 1–3 ). Internal copulatory apparatus as in figs. 4–5 ............................................................................................................. Apetaenuslitoralis

- Flies with body bearing a quite normal setal vestiture. Fully winged species ( fig. 11 ), at times with uncommon micropterous and brachypterous individuals ( fig. 10 ). Head with normal setal vestiture. Postocellar setae always present, inclinate or slightly cruciate; postpronotal lobe with at most few, tiny hairs; dorsocentrals 1+4; 2 postalars, rarely inner seta weak, hairlike. Setulae of mesonotum tiny. Pleurae with usual, scarce, setal vestiture; 2–3 anepisternal setae of normal length; katepisternum bearing 1 long seta on upper part. Forefemur in both sexes with 3–4 very long, strong, distinctive, postero-ventral setae on distal two-thirds, besides usual 1–2 setae on proximal third. Tarsi, in fully-winged individuals, of normal length, with basitarsomere long and slender in females, distinctly longer than tarsomeres 2–4 together, noticeably shorter in males, in particular basitarsomere of hind leg. Female abdomen with syntergite 1+2 deeply fissured medially ( fig. 13 ); tergites 1 and 2 fully coalesced; tergite 2 generally bearing a peculiar tuft of characteristically upwards oriented, very long setae on latero-ventral portion; tergite 3 variable, undivided or split medially; sternites 1–3 lacking. Male terminalia with ventral epandrial lobe not curved inwards, knoblike, bearing a tuft of several, long setae ( figs. 6–7 ). Internal copulatory apparatus as in fig. 8 ................................................................................................................................... Apetaenus enderleini

Figures

FIGURES 11–16. Specimens from the Crozet archipelago (figures 11–14). 11. Apetaenus enderleini, habitus of macropterous male; 12. Apetaenus litoralis, habitus of male; 13. Apetaenus enderleini, female abdomen showing the deep, median split on syntergite 1+2 (specimen photographed in alcohol); 14. Apetaenus litoralis, female abdomen dorsally; 15. Apetaenus litoralis, habitus of female; 16. ditto, head lateral view. (Figures 15–16, after Séguy, 1940, © Publications Scientifiques du MNHN, Paris).

FIGURES 8–10. 8. Internal copulatory apparatus of Apetaenus enderleini [nomen novum], lateral view. Scale bar = 0.1 mm; 9. vestigial wing of Apetaenus litoralis; 10. Range of wing reduction, brachypterous to micropterous, in Apetaenus enderleini. (Figure 9 after Séguy, 1940; figure 10 after Séguy, 1965; © Publications Scientifiques du MNHN, Paris).

FIGURES 1–2. Apetaenus litoralis Eaton. 1. Male terminalia postero-lateral view; 2. ditto, caudal view. Scale bar = 0.1 mm.

FIGURES 3–5. Apetaenus litoralis Eaton. 3. Male terminalia ventral view. Scale bar = 0.1 mm; 4. internal copulatory apparatus lateral view (after Hennig, 1971, courtesy of SMNS); 5. ditto, ventral view (after Séguy, 1940, © Publications Scientifiques du MNHN, Paris).

FIGURES 6–7. Apetaenus enderleini [nomen novum]. 6. Male terminalia postero-lateral view; 7. ditto, caudal view. Scale bar = 0.1 mm.