Lebanorthocladius furcatus, Veltz & Azar & Nel, 2007

Veltz, Isabelle, Azar, Dany & Nel, André, 2007, New chironomid flies in Early Cretaceous Lebanese amber (Diptera: Chironomidae), African Invertebrates 48 (1), pp. 169-191 : 179-182

Lebanorthocladius furcatus sp. n.

Figs 9–12

Etymology: After the forked gonostylus, characteristic of the male.

Description: Head 0.12 mm long. Ocelli absent. Antenna 0.56 mm long, almost 5 times length of head, distinctly hairy, with 13 flagellomeres covered with long setae (shortest 0.04 mm, longest 0.2 mm), scape broad and short, rounded, pedicel very short,

flagellomere 13 very long (0.07 mm). Eye bare, with a small dorso-medial extension, with 3 rows of ommatidia at minimum width. Clypeus with few dorsal setae. Mouthparts lacking functional mandible; 4 palpomeres with numerous setae, all of approximately the same length. Postocular, frontal, inner vertical and outer vertical setae not visible, possibly absent.

Thorax 0.46 mm long, 0.38 mm high; postnotum without visible setae, and no visible longitudinal median groove; surface of scutellum without visible setae; acrostichals and dorsocentrals not visible, probably absent; scutal tubercle present; scutum without median longitudinal groove; epimeron II, posterior mesanepisternum II and dorsal antepronotum bare; no lanceolate setae on scutum; antepronotal lobes not widely separated; anapleural suture distinct.

Wing macropterous, 0.84 mm long, 0.26 mm wide, hyaline, membrane bare. Costa ending just beyond insertion of last branch of radius, distinctly shorter than cross-vein RM. Radius with only 3 branches R 1, R 2+3, and R 4+5; R 2+3 well separated from R 1 and R 4+5, R 2+3 not forked into R 2 and R 3, ending in costa; R 1 and R 4+5 elongate, separated from costa until apex; area between costa and R 4+5 broad. Only M 1+2 and M 3+4 present; cross-vein MCu absent; Cu 1 nearly straight. Anal vein An 2 absent; squama without setae. Halter 0.12 mm long.

Fore femur length 0.34 mm, tibia 0.36 mm, tarsus 0.62 mm; mid femur 0.34 mm, tibia 0.44 mm, tarsus 0.5 mm; hind femur 0.38 mm, tibia 0.48 mm, tarsus 0.6 mm. All tarsomeres of fore, middle and hind legs cylindrical, not cordiform; first tarsomere of fore leg distinctly shorter than fore tibia. Hind tibia with one spur and a comb comprised of basally separated spines. Fore coxa not enlarged.

Abdomen 1 mm long, 0.16 mm wide. Gonostylus hinged to gonocoxite and folded inward; short and bifurcate. Gonocoxite with numerous long setae, elongate. Superior (?) volsella large, digitiform; no median volsella and no apparent inferior volsella.Anal point sharp and long, 0.4 mm wide at base, 0.07 mm high.

Holotype: Specimen 5 B, male. LEBANON: Mont Lebanon district [Mouhafazit Jabal Loubnan]: Hammana / Mdeyrij, Caza Baabda; Early Cretaceous (D. Azar coll.).

Other material studied: Specimen 574 I, male, with genital organs missing, from the same locality and possibly also belonging to this species.

Discussion: This species belongs to the subfamily Orthocladiinae because of the following characters: wing present; cross-vein MCu absent; first tarsomere of fore leg distinctly shorter than fore tibia; hind tibia with one spur and a comb comprised of basally separated spines; gonostylus hinged to gonocoxite and folded inward; antepronotal lobes not widely separated; fore coxa not enlarged; anapleural suture distinct ( Oliver 1981; Oliver & Dillon 1989). Except for the key to Holarctic genera of Cranston et al. (1989), and the key to Palaearctic genera in Saether et al. (2000), there is no recent world revision of the orthocladiine genera.

Few recent genera have a double, forked, or broad triangular gonostylus, as in Lebanorthocladius gen. n., viz. Aagaardia Saether, 2000 , Brillia Kieffer, 1913 , Diplosmittia Saether, 1981 , Plhudsonia Saether, 1982 , Propsilocerus Kieffer, 1923 (= Tokunagayusurika Sasa, 1978 ), Zalutschia Lipina, 1939 , some Chaetocladius Kieffer, 1911 , some Parachaetocladius Wülker, 1959 , and one Orthocladius van der Wulp, 1847 . Brillia , Diplosmittia , Plhudsonia and Propsilocerus have a double gonostylus. Lebanorthocladius differs from all of the other genera by the following combination of characters: straight Cu 1, very short costal extension, and R 4+5 ending opposite to apex of M 3+4. All genera except Aagaardia also have setae on squama and all lack a scutal tubercle. The volsellae are of the type found in the Brillia group of genera, present, for instance, in Eurycnemus van der Wulp, 1874 (Fittkau 1974; Saether 1982, 2000 b; Chaudhuri & Bhattacharyay 1989; Cranston et al. 1989; Kawai 1991; Kobayashi & Sasa 1991; Niitsuma 1991; Saether & Wang 1992, 1996; Andersen & Saether 1993 a, b; Saether &Andersen 1993, 1995; Saether & Ferrington 1993; Kobayashi 1994; Boothroyd 1994, 1999; Boothroyd & Cranston 1994; Epler & de la Rosa 1995; Ferrington & Saether 1995; Oliveira et al. 1995; Saether & Kristoffersen 1996; Harrison 1997, 2000; Wiedenbrug & Fittkau 1997; Wang & Saether 1998, 2002; Cranston & Edward 1999; Saether & Ekrem 1999; Yamamoto 1999; Cranston 2000; Maheshwari & Maheshwari 2001; Mendes et al. 2004 a, b).

Figures

Fig. 9. Lebanorthocladius furcatus gen. et sp. n., holotype 5B, general habitus, scale bar = 0.5 mm.

Figs 10–12. Lebanorthocladius furcatus gen. et sp. n., holotype 5B: (10) wing, scale bar = 0.5 mm; (11, 12) dorsal and ventral aspects of male genitalia, scale bar = 0.1 mm.