Lachnus pseudonudus Kanturski & Wieczorek

Kanturski, Mariusz, Wieczorek, Karina & Junkiert, Lukasz, 2014, A new oak-feeding species of Lachnus Burmeister and some remarks on the taxonomic status of L. chosoni Szelegiewicz (Hemiptera, Aphididae, Lachninae), Deutsche Entomologische Zeitschrift 61 (1), pp. 77-83 : 77

Lachnus pseudonudus Kanturski & Wieczorek sp. n. Figures 1, 2, 3; Table 1, 2

Description.

Apterous viviparous female. Colour in life unknown. Pigmentation of mounted specimens: head, pronotum and mesonotum sclerotised, covered by light brown sclerotic shield. Antennal segments light brown. Fore and middle femora light brown, hind femora brown with pale proximal area to about ¼ length. Tibiae from proximal part to about ½ length and on distal parts brown, otherwise yellowish (Fig. 3a). Tarsi brown. Abdomen pale. Siphuncular sclerites pale to light brown. Subgenital and anal plate brown. Body large, egg-shaped (Fig. 1). Head densely covered by short, thick and forked setae, shorter than setae on antennal segments. Frons flat. Head width 0.49-0.57 times length of antennae. Antennae 6-segmented (Fig. 2a), 0.44-0.53 times length of body. Ant. segm. III slightly shorter than ant. segm. IV+V+VI, with 0-1 secondary rhinarium. Ant. segm. IV slightly shorter than, or as well as long as ant. segm. V, with 0-3 secondary rhinaria. Ant. segm. V always longer than ant. segm. VI with 1 primary and 1-2 accessory rhinaria. Ant. segm. VI base (IVa) longer than terminal process (IVb), with 1 big primary rhinarium with sclerotised rosette and 6-7 small accessory rhinaria, adjoining each other (Fig. 2b). IVb 0.24-0.33 times length of VIa with 3 apical and 5-7 subapical setae, which are shorter and slightly thicker than basal setae. Other antennal ratios: VI:III 0.25-0.31; V:III 0.44-0.54; IV:III 0.37-0.48; IV:V 0.80-1.03. Ant. segm. I–VIa densely covered with very thin, hair-like, pointed setae. Longest seta on ant. segm. III 1.10-1.66 times basal articular diameter of this segment. Rostrum long, reaching siphunculi or genital plate (in some specimens reaching only hind coxae). Apical segment of rostrum (ARS) pointed, 0.38-0.50 times ant. segm. III and 1.00-1.19 times second segment of hind tarsus (HT II), with 4 primary and 18 accessory setae (Fig. 2c). Mesosternal tubercles absent. Hind legs long, 1.18-1.45 times length of body. Some setae on hind tibiae 4-5 times longer than other setae, hair-like, 0.17-0.22 mm long (Figs 2d, 3a). First segment of hind tarsus (HT I) with 14 ventral setae (Fig. 2d). HT II 0.36-0.45 times ant. segm. III and 1.37-1.50 times ant. segm. VI. Abdomen membranous, cuticle with very densely wrinkled surface in transverse rows. Siphuncular sclerites well-developed, usually slightly oval, around pore a very well-developed flange with 8-10 rows of polygonal reticulation (Figs 2e, 3e). Dorsal abdominal segments covered with 3-4 rows of very short, blunt, capitate, spatulate or club-shaped setae, 0.010-0.020 mm long, arising from dark brown ring-like bases (Fig. 2f). Each abdominal segment with 3 pairs of brown, rounded sclerites. Subgenital plate well-developed, with indentation from posterior side. Cauda circular or semicircular with 22-24 long and pointed setae which are longer and thicker than those on legs. Anal plate well-developed, sclerotised.

Diagnosis.

The new species can be distinguished from Lachnus crassicornis as well as from the other Lachnus species by the sparse dorsal chaetotaxy and extremely short, inconspicuous setae with blunt, slightly spatulate, capitate or club-shaped apices. The new species is also characterised by siphunculi with a very well-developed and almost transparent flange with 8-10 rows of polygonal reticulation. Main morphological and biometric differences between Lachnus pseudonudus Kanturski & Wieczorek, sp. n. and Lachnus crassicornis are given in Table 2.

Etymology.

The name of the new species is derived from characteristically short and inconspicuous setae on the dorsal part of the thorax and the abdomen.

Biology and host plant.

The species live on branches and shoots of Quercus ithaburensis subsp. macrolepis (Kotschy) Hedge & Yalt. (= Quercus aegilops ) and is visited by the ant species Liometopum microcephalum (Panzer, 1798) ( Canakçioglu 1975).

Distribution.

Turkey, Uşak-Eşme.

Material examined.

Holotype: one apterous viviparous female marked as 1. TURKEY, Uşak-Eşme, 850 m, 10.VI.1964, no 731/64, 45a1, M. Canakçioglu leg. BMNH.

Paratypes. Same locality as holotype: one apterous viviparous female marked as 2, no 731/64, 45a1; four apterous viviparous female marked as 1, 2, 3, 4, no 731/64, 45a2 BMHN; four apterous viviparous female marked as 1, 2, 3, 4, no 731/64, 45a3 UŚ.

Other material examined: 22 apterous viviparous females, same locality as holotype: no 731/64, 45a4-45a9 BMHN.