Helius minutus ( Loew, 1850 )

Kania, Iwona, 2014, Subfamily Limoniinae Speiser, 1909 (Diptera, Limoniidae) from Baltic amber (Eocene): the genus Helius Lepeletier & Serville, 1828, Zootaxa 3814 (3), pp. 333-352 : 340-341

Helius minutus ( Loew, 1850)

( Figs 6 A–C)

*1850 Rhamphidia minuta , p. 37

1856 Rhamphidia minuta Loew : Giebel, p. 242

1906 Rhamphidia minuta Loew : Meunier, p. 358

v.1906 Rhamphidia pulchra Loew (Meunier) : Meunier, p. 358, p. 364, Pl. XII, fig. 3–4 v.1906 Antocha succinea Meunier : Meunier, p. 358, 368, Pl. XII, fig. 8, 9 and 10 1931 Helius minutus (Loew) : Alexander, p. 42

vp.1931 Helius pulcher (Meunier) [sic!]: Alexander, p. 42 vp.1931 Rhamphidia pulchra (Meunier) : Alexander, p. 42 v.1931 Antocha succinea Meunier : Alexander, p.42

1985 Helius minutus (Loew) : Krzemiński, p. 116

v.1985 Helius abditus Krzemiński : Krzemiński, p. 116, figs. 9, 10 1993 Helius pulcher: Krzemiński , p. 597

1993 Helius minutus (Loew) : Krzemiński, p. 598

v.1993 Helius minutus (Loew) , p. 599, Fig. 5–7 — neotype designation 1993 Antocha succinea Meunier : Krzemiński, p. 597

1993 Helius succineus: Krzemiński , p. 597—nomen nudum 1994 Helius minutus Loew : Evenhuis, p. 73

1994 Antocha succinea Meunier : Evenhuis, p. 73 [sic!]

Remarks. The species Rhamphidia minuta Loew, 1850 was not clearly characterized by Loew. Meunier (1906) stated that he was not able to locate the specimen examined by Loew. The unavailability of Loew’s specimen was also noted by Alexander (1931), who, however, placed it in the genus Helius , resulting in combination Helius minutus ( Loew, 1850) . Krzemiński (1985) stated that material of Helius minutus (Loew) is lost. Subsequently, Krzemiński (1993) designated neotype for this species, based on the specimen deposited in the Museum of the Earth, PAS, Warsaw. He also synonymized Helius abditus Krzemiński, 1985 under Helius minutus (Loew) , and proposed to synonymize Antocha succinea Meunier, 1906 under Helius minutus (Loew) . It must be noted that specimen No. 4557 in Meunier (1906) paper (specimen No. Z-4557, examined by Krzemiński, deposited recently in Palaeontological Institute in Göttingen—Klebs collection) is the type specimen of Antocha succinea Meunier, 1906 , but Krzemiński (1993) did not indicate, that it is the type, and ascribed the specimen as material of Helius minutus . Krzemiński (1993) also listed specimens: K-4265 (Klebs collection, No. 4265) and Z-253 (Klebs collection No. 253; both presently deposited in Göttingen), which were ascribed to Helius pulcher by Alexander (1931) as belonging to Helius minutus .

Material examined. Neotype: No. 7895 (male), ( MEPAS); additional material: No. MB.J. 224 (male), Coll. Kühl ( ZMHB); No. K-4265, Z-253 (male), No. K1696, Z-4557 (male) ( GMUG), No. MP/3342 (male) ( ISZP).

Diagnostic characters. Rostrum approximately 1.2x the length of the head ( Fig. 6 B), approximately equal the length of palpus, or palpus slightly longer, rostrum shorter than antenna; antenna more than twice longer than the rostrum; outer gonostylus short, straight, with two broad spikes apically; vein r-m rather long, well expressed, cross-vein m-cu almost in proximal 1/3 of d-cell base.

Redescription. Body: the length of specimens approximately 3.03–5.7 mm.

Head ( Fig. 6 A, 10D): rostrum 0.64–0.73 mm long (neotype), approximately 1.2x the length of the head ( Fig. 6 B); antenna 16-segmented, 1.15 mm long, more than twice longer than rostrum; scape cylindrical, large; pedicel barrel-shaped, broad; first flagellomere short, broad, flagellomeres 2–16 cylindrical with four elongated setae ( Fig. 10 C); 1.5–2 times than the segments bearing them; last flagellomere with two elongated setae at apex.

Palpus ( Fig. 6 A, 10C): almost as long as the rostrum or slightly longer, the last palpal segment 0.22 mm long, almost equal two preceding segments together; first to third palpal segments 0.11 mm long.

Wing ( Fig. 6 C): wing 4.4–4.8 mm length and 1.01 mm wide (neotype); pterostigma present, large and oval; vein Sc ending opposite 1/3 the length of Rs; cross-vein sc-r at the end of Sc; R1 ending opposite 1/4 of R2+3+4 length; r-r (R2) atrophied; R2+3+4 elongated, straight; d-cell elongated, closed; M3 longer than d-cell, M3 longer than half the length of R5; cross-vein m-cu almost in proximal 1/3 of d-cell base; A1 and A2 elongated, straight.

Hypopygium: outer gonostylus short, broad, with two broad spikes apically; inner gonostylus rather short, lobe-shaped; gonocoxite basally equipped with large, broad process terminating into narrow, acute spine.

Remarks. Antenna is 16-segmented like in other species of the genus Helius from Baltic amber, but the last flegellomere is comparatively small, distinctly shorter than the rest. The wing venation in specimens No. K-4265, Z-253 differs from the other specimens of this species by following features: Sc is ended opposite midlength of Rs, R1 is ended opposite midlength of R2+3+4, d-cell is very short and broad and cross-vein m-cu occur in half of d-cell length.

Figures

FIGURE 5. Helius hoffeinsorum sp. nov., No. 1462 (male), A, hypopygium (dorsal view); B, head; C, relation between the length of palpus (p), antenna (a), rostrum (r) and head (h); D, wing venation. Abbreviation of male hypopygium: gx—gonocoxite, ing—inner gonostylus, oug—outer gonostylus, aed—aedeagus, p—paramere.

FIGURE 6. Helius minutus Loew, 1850, No. MB. J. 225 (male); A, head (after Krzemiński 1993); B, relation between the length of palpus (p), antenna (a), rostrum (r) and head (h); C, wing venation.

FIGURE 7. Helius pulcher Loew, 1850, No. MB. J. 358 (female) A, head; B, relation between the length of palpus (p), antenna (a), rostrum (r) and head (h); C, wing venation.

FIGURE 10. Morphology of Helius from Baltic amber. A H. hoffeinsorum sp. nov., No. 1462 (male), holotype, the body, lateral view; B. H. similis sp. nov., No. 3413 (male) head and thorax latero-ventral view, C – D. H. minutus Loew, 1850, No. 7895 (male), neotype, C. antennae, palpi, rostrum, D. head.