Helius fossilis, Kania, Iwona, 2014

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 : 337-338

Helius fossilis sp. nov.

( Figs 3 A–C)

Material examined. Holotype: No. 587 (RS64) (male) ( SNMG); additional material: No. 1690 (female) Coll. Ch. and H. W. Hoffeins ( SDEI).

Etymology. From Latin fossilis , fossil. The species epithet is an adjective.

Diagnosis. Rostrum very elongated, approximately three times as long as the head, longer than palpus, longer than antenna; palpus 0.33x the length of the rostrum; the last palpal segment approximately half the length of all the preceding segments together; vein r-m rather long, well expressed, cross-vein m-cu in 1/2 of d-cell base.

Description. Body ( Fig. 11 A): the length of specimen 4.36 mm (holotype).

Head ( Figs 3 A, 11B): head width 0.48 mm; rostrum length 1.68 mm, very elongated ( Fig. 3 B); antenna 1.13 mm long (holotype), 16-segmented, shorter than rostrum; scape cylindrical, large; pedicel large, its distal part conspicuously widened; first flagellomere barrel-shaped, flagellomeres 2–16 cylindrical, rather short, with four elongated setae each; setae almost the same length or slightly longer than the length of the segments bearing them.

Palpus ( Fig. 3 A): 0.53 mm long (holotype); the length of last palpal segment 0.22 mm, penultimate 0.1 mm, the second segment 0.1 mm (holotype); the last palpal segment approximately half the length of all the preceding together, equal the length of two penultimate segments.

Wing ( Fig. 3 C): wing 4.90 mm length and 1.4 mm wide (holotype); pterostigma absent; vein Sc not elongated, ending before midlength of Rs; cross-vein sc-r behind the end of Sc; R1 ending at the level of 1/3 of R2+3+4 length; r- r (R2) atrophied; R2+3+4 elongated, straight; d-cell closed, very broad and long; M3 twice the length of d-cell, M3 longer than half the length of R5; cross-vein m-cu in 1/2 of d-cell base; A1 and A2 elongated, distinctly straight.

Hypopygium: 0.36 mm long, not well visible; gonocoxite elongated and relatively narrow.

Remarks. The species H. fossilis sp. nov. distinctly differ from most of other species of this genus from Baltic amber in very elongated rostrum, which characterizes also H. mutus . In both species rostrum is shorter than half the body length. They differ in following features: in H. mutus antenna is about half the length of rostrum, palpus is about half the length of antenna, in H. fossilis antenna is much longer than half the length of rostrum, palpus is longer than half the antenna length. These species differ also in wing venation details. In contrast to H. mutus , H. fossilis is characterized by wing without pterostigma, vein R1 ending in 1/3 of R2+3+4 (opposite 1/4 of its length in H. mutus ).

Figures

FIGURE 3. Helius fossilis sp. nov. No. 587 (RS 64) (male); A, head; B, relation between the length of palpus (p), antenna (a), rostrum (r) and head (h); C, wing venation.

FIGURE 11. Morphology of Helius from Baltic amber. A – B H. fossilis sp. nov., No. 587 (RS 64) (male), holotype, A. the body, lateral view; B. head, lateral view C. H. hoffeinsorum sp. nov., No. 1462 (male), hypopygium; D – E H. formosus Krzemiński, 1993, No. 225 (female), holotype, D. antennae, E. wing. Abbreviation of male hypopygium: gx—gonocoxite, ing—inner gonostylus, oug—outer gonostylus, aed—aedeagus, p—paramere.