Burmacompsocus coniugans Sroka & Nel, 2017

Nel, André, 2017, New species of Compsocidae (Insecta, Psocodea) from Cretaceous Burmese amber, Zootaxa 4320 (3), pp. 597-600 : 598

Burmacompsocus coniugans Sroka & Nel , sp. nov. ( Figs 1–10 )

Etymology. The name of the new species is derived from the Latin expression for "fusing" and refers to the fusion of veins Rs and M in the forewing, which probably constitutes the most reliable distinguishing character.

Diagnosis. Forewing with Rs fused with M for a short distance, row of denticles on anterior carina of forefemur absent, lacinia with pronounced subapical teeth.

Description. Holotype specimen represents male. Body surface strongly corrugated. No flattened scales present on surface of body and/or wings.

Head 0.52 mm long, 0.58 mm wide. Three ocelli situated on slightly elevated tubercle ( Figs 1, 3 ). Lacinia curved outwards apically, with several distinct subapical denticles on inner side ( Fig. 5 ). Denticles not observable from lateral view, from where lacinia appears rod-like (see Fig. 5 ). Maxillary palpi ( Fig. 5 ) with three distinguishable segments, basal segment not visible. Apical segment 0.13 mm long, slightly widened distally, subapical segment 0.08 mm long, cylindrical. Labial palpi short, rounded apically, bearing numerous long hair-like setae ( Fig. 5 ). Antennae filiform, composed of 13 segments, equipped with sparse long hair-like setae. Length of segments decreasing apically.

Wings hyaline, covered with numerous short microtrichia, denser along wing veins. No long setae on veins and/or wing margins. Forewing ( Figs 1, 3 ) 1.87 mm long, 0.73 mm wide. Pterostigma 0.34 mm long, 0.13 mm wide, basally closed, not sclerotized. Stems of M and Rs fused for short distance. Areola postica 0.4 mm long, 0.12 mm wide, not connected to M by crossvein. Nodulus present. A2 not joining A1. Hind wing ( Figs 9, 10 ) 1.55 mm long, 0.44 mm wide. First segment of Rs not visible. M two-branched.

Tibiae with rows of long spine-like setae. Group of thicker setae apically. Tarsi ( Fig. 7 ) three-segmented, first segment longest, equipped with rows of spine-like setae, shorter than on tibiae. Second and third segments approximately equal in length, tiny spine-like setae situated apically. Claws with two subapical denticles, pulvillus not visible ( Fig. 8 ).

Abdomen 1 mm long, slightly deformed. Hair-like setae observable in posterior part. Genitalia partly obscured, parameres and aedeagus partially observable ( Fig. 6 ). Hypandrium broadly rounded.

Affinities. Following Mockford (1967, 1993) and Smithers (1990), B. coniugans exhibits a combination of morphological traits diagnostic for the recent family Compsocidae Mockford of the suborder Troctomorpha, namely (only characters visible in the holotype of B. coniugans listed): antenna with 13 segments, tarsi three-segmented, macroptery with complex forewing venation, pterostigmal area not sclerotized or more opaque than rest of membrane, forewing with nodulus, hind wing with M forked, absence of flattened scales on wings and body.

B. coniugans also follows most of the additional characteristics of the genus Burmacompsocus as described by Nel and Waller (2007): lacinia tip with lateral cusp curved outward, claw with two preapical denticles, pterostigma closed basally, forewing veins 1A and 2A not joined, first segment of Rs in hind wing absent. At the same time, B. coniugans differs in several aspects from B. perreaui , the type species of Burmacompsocus . The forewing veins Rs and M are connected by a crossvein in B. perreaui (see fig. 1D in Nel & Waller 2007), whilst these veins are fused for a short distance in B. coniugans ( Fig. 3 ). Another distinguishing character is represented by the row of denticles on anterior carina of the forefemur, mentioned by Nel and Waller (2007) as present in B. perreaui and missing in B. coniugans . Moreover, Nel and Waller (2007) described lacinia tip of B. perreaui bearing few indistinct rounded denticles, whereas B. coniugans exhibits relatively pronounced denticles subapically on lacinia ( Fig. 5 ).

In addition to B. perreaui , the genus also encompases Burmacompsocus banksi (Cockerell, 1916) . This species was only tentatively placed in the genus, based on its similar wing venation ( Mockford et al. 2013). This attribution was confirmed by Azar et al. (2016), however a resolution of the specific placement of B. banksi was seen as impossible due to the fragmentary preservation of the fossil ( Azar et al. 2016). We concur with this opinion and exclude B. banksi from the comparative study.

Figures

FIGURES 1 – 10. Burmacompsocus coniugans sp. nov.: (1) photograph of holotype (dorsal view); (2) photograph of holotype (ventral view); (3) drawing of holotype (dorsal view) with marked forewing venation pattern; (4) drawing of holotype (ventral view); (5) detail of mouthparts (ventral view); (6) detail of genitalia (ventral view); (7) tarsus of left hind leg; (8) detail of claw; (9) right hind wing, visible part; (10) left hind wing, visible part.