Stenomicra gracilior, Roháček, 2011

Roháček, Jindřich, 2011, Taxonomy of Stenomicra cogani, with description of S. gracilior sp. nov. from Turkey and comparative morphology of terminalia in Stenomicridae (Diptera), Acta Entomologica Musei Nationalis Pragae 51 (2), pp. 697-722 : 708-712

Stenomicra gracilior sp. nov.

( Figs. 6 , 21–34 )

Stenomicra cogani: ROHÁČEK (2011) : 150 (misidentification, record from Turkey).

Type material. HOLOTYPE: J, labelled:‘S. TURKEY: Antalya prov., Manavgat 7.1 km SE, 0–1 m, mouth of Manavgat river, 36°44′17″N, 31°29′44″E, 11.5.2011, J. Roháček leg.’, ‘sweeping marshland graminoids: Typha , Scirpus , Phragmites , Juncus etc.’, ‘ Holotypus J, Stenomicra gracilior sp.n., J. Roháček det. 2011’ (red label). PARATYPE: ♀ with same locality data but with yellow label: ‘ Paratypus ♀, Stenomicra gracilior sp.n., J. Roháček det. 2011’. Both specimens with genitalia prepared, deposited in SMOC.

Diagnosis. A small yellow species externally very similar to Stenomicra cogani including the absence of posterior cross-vein (dm-cu). It differs from the latter species by anterior fronto- orbital seta shorter, postvertical setae shorter and closer to each other and only 4 ac setulae, in male sex also by all setae darker and f 2 with a row of 11 anteroventral setae and in female by larger brown spots on abdominal terga. The principal differences are, however, in the male and female terminalia: male T6 longer and less transverse, ventral plate of synsternum S6–S8 (original S6) shorter and asymmetrical, epandrium wider, gonostylus more slender, with reduced chaetotaxy and without wrinkles in central concavity, filum of distiphallus with single apical tooth-like projection, phallapodeme slender, female syntergosternum T7+S6+S7 with lateral processes reduced to short bulges, female T8+S8 longer and its ventral bare part (= S8) as long as dorsal part (= T8), spermathecae shorter and with only 4 proximal bulges, female T10 completely absent.

Description. Male. Total body length 1.58 mm. Colouring closely resembling that of male S. cogani but setae (macrosetae in particular) distinctly darker, brownish.

Head ( Figs. 21, 22 ) of the same shape, structure and colour as that of S. cogani but antenna darker yellow, with pedicel orange, darkest on inner side dorsally. Also cephalic chaetotaxy as in S. cogani but all macrosetae darker, anterior ors shorter and weaker (one-third length of the posterior ors), pvt setae shorter and more medially inserted (closer to each other) and ventroclinate peristomal setae fewer (5 only), see Fig. 22 .

Thorax with same structure and colouring as in S. cogani . Thoracic chaetotaxy also similar to that species but all setae brownish and number of ac setulae reduced to 4, arranged in single row not reaching beyond level of anterior dorsocentral seta.

Wing ( Fig. 6 ) with the same venation (including loss of dm-cu cross-vein) and colouring as that S. cogani ; also haltere similar. Wing measurements: length 1.63 mm, width 0.51 mm, Cs 3: Cs 4 = 6.37.

Legs yellow as in S. cogani but not only last but 3–4 terminal tarsal segments of fore and mid leg darkened, pale brown. Fore femur (f 1) and t 2 with the same chaetotaxy but f 2 with anteroventral row longer and consisting of 11 ochreous setae ( Fig. 23 ).

Abdomen closely resembling that of S. cogani but somewhat wider, with T3–T5 more transverse; T4 not only narrower but also shorter than T5. All preabdominal sterna (S1–S5) also wider and more transverse but their chaetotaxy similar to those of S. cogani .

Postabdomen. T6 yet larger than in S. cogani , two-thirds of length of T5 and less transverse, only twice as wide as long. S6–S8 (see Fig. 29 ) forming ring-shaped synsternum but shorter than in S. cogani and its plate-shaped ventral part (original S6) asymmetrical, anteromedially with deeper emargination and posteromedial projection (including marginal denticles) reduced.

Genitalia generally formed as in S. cogani but differing as follows. Epandrium ( Figs. 24, 25 ) distinctly broader in caudal view, less densely setose. Anal fissure yet smaller; cerci as in S. cogani . Gonostylus ( Figs. 24–26 ) with distinctly more slender distal part (particularly in caudal view, Fig. 24 ), smooth (without wrinkles) in concavity, and with setosity reduced (4 long setae proximally, 2–3 short setae on darkened apex). Medandrium with lateral sclerites shorter and each with 1–2 setae ( Fig. 24 ). Hypandrium ( Fig. 28 ) of somewhat different shape; with left pregonite (fused with hypandrium) bearing only 2 setae. Aedeagal complex ( Fig. 28 ) with phallophore hardly curved. Distiphallus with saccus more finely striated and ventrally bearing a group of 4 pale setae. Filum of distiphallus more bent and its apex differently formed ( Figs. 27, 28 ), with single tooth-like projection and several small denticles on tip. Phallapodeme ( Fig. 28 ) markedly different from that of S. cogani , very slender including both anterior rod and basal projection. Ejacapodeme ( Fig. 28 ) of similar shape to that of S. cogani but more slender.

Female. Similar to male unless mentioned otherwise. Total body length 1.75 mm. Setae darker, macrosetae blackish brown. Face with distinct brown U-shaped line bordering parafacialia as in S. cogani . f 1 with setae in posterodorsal row as short as in male; f 2 uniformly setulose, without long anteroventral row of setae. Wing measurements: length 1.97 mm, width 0.59 mm, Cs 3: Cs 4 = 6.67. Abdomen ( Figs. 30, 31 ) with darker pigmentation than that of S. cogani , with brown lateral spots on T2–T4 extended and in T3 and T4 forming almost complete band ( Fig. 30 ); S2 and, particularly, S5 narrower ( Fig. 31 ).

Postabdomen ( Figs. 33, 34 ) similarly formed to that of S. cogani but differing as follows. T6 somewhat shorter, more transverse. Syntergosternum T7+S6+S7 longer and narrower, with lateral processes reduced to short bulges ( Fig. 34 , arrow). Syntergosternum T8+S8 longer and its ventral part (= S8) not strip-like but almost as long as dorsal part (= T8) although unpigmented and completely bare. Genital chamber similar to that of S. cogani but spermathecae ( Fig. 32 ), particularly their proximal part, shorter and with only 4 bulges around duct insertion; also collar distinctly shorter. T10 (supra-anal plate) seems to be completely absent ( Fig. 33 ) and S10 (subanal plate) is somewhat shorter, more produced posteromedially ( Fig. 34 ) and with longer setae also posteriorly (in addition to long micropubescence). Cercus closely resembling that of S. cogani .

Discussion. Because of great external similarity of S. gracilior sp. nov. to S. cogani this new species was previously misidentified as the latter species and recorded under this name as the first representative of Stenomicridae from Turkey ( ROHÁČEK 2011). However, subsequent detailed evaluation of the variability of S. cogani revealed that the dissimilarities found in Turkish specimens (although relatively small) enable their safe separation from the European specimens of S. cogani . Because also the presumption that the more slender gonostylus (and other features in the male genitalia) of Turkish males are caused by their small size was disproved by the examination of several yet smaller European males of S. cogani and additional structural differences were also found in the female terminalia, the specimens from Turkey are described above as a new species.

Biology. The type specimens were collected in a Mediterranean subcoastal wetland area, swept from graminoid vegetation composed mainly of various species of Typha , Scirpus , Phragmites , and Juncus (for habitat photograph see ROHÁČEK 2011: Fig. 6 ) on May, 11 th.

Distribution. Southern Turkey (Antalya province).

Figures

Figs. 5–6. Wings of Stenomicra species. 5 – Stenomicra cogani Irwin, 1982, female (Czech Republic: N. Bohemia), length 1.95 mm; 6 – S. gracilior sp. nov., male (holotype), length 1.63 mm. Photo by J. Roháček.

Figs. 21–23. Stenomicra gracilior sp.nov., male (holotype). 21 – head frontally; 22 – head, laterally; 23 – f2 anteriorly. Scales = 0.2 mm. For abbreviations see text (p. 701).

Figs. 24–29.Stenomicra gracilior sp. nov., male (holotype).24 – external genitalia, caudally; 25 – genitalia, laterally; 26 – gonostylus, subventrally, widest extension; 27 – filum of distiphallus, anteroventrally; 28 – internal genitalia, laterally; 29 – pregenital synsternum S6–S8, ventrally. Scales = 0.1 mm (Figs. 24, 25) and 0.05 mm (Figs. 27–29). For abbreviations see text (p. 701).

Figs. 30–34. Stenomicra gracilior sp. nov., female (paratype). 30 – abdomen dorsally; 31 – same, ventrally; 32 – spermathecae; 33 – postabdomen dorsally; 34 – same, ventrally. Scales = 0.2 mm (Figs. 30, 31), 0.05 mm (Fig. 32) and 0.1 mm (Figs. 33, 34). For abbreviations see text (p. 701).