A new species of the subgenus Scymnus from Pakistan (Coleoptera, Coccinellidae)

Abstract A new species, Scymnus (Scymnus) contortubus Rashid, Chen & Wang, sp. n., is described and illustrated from Pakistan. A diagnosis, remarks, illustrations, and a distribution map are provided of the new species and its most similar congener, S. (S..) nubilus Mulsant.


Introduction
The subgenus Scymnus was established by Mulsant, 1850 with Coccinella rufipes Fabricius, 1798 as the type species, based on the presence of an 11-segmented antenna and the incomplete abdominal postcoxal line.
The genus Scymnus Kugelann, 1794 belonged to the tribe Scymnini Mulsant, 1846 in the subfamily Scymninae (Sasaji 1968;Kovář 1996). However, Ślipiński (2007) presented a two-subfamily system, moving the genus Scymnus to the tribe Coccidulini in the subfamily Coccinellinae. Further studies based upon molecular and morphological characters supported Ślipiński's (2007) division of Coccinellidae in two subfamilies, Coccinellinae and Microweiseinae (Giorgi et al. 2009;Seago et al. 2011). Recent study on the Cucujoidea (Robertson et al. 2015) has recovered Coccinellidae as belonging to the superfamily Coccinelloidea together with eight other families of the former Cerylonid Series.
Members of the genus Scymnus Kugelann, 1794 are predatory and mostly feed on aphids, adelgids, and scale insects, playing an important role in regulating pest populations (Chen et al. 2016). Prior to the present study, 58 species were reported in the subgenus Scymnus (Scymnus) from the Oriental Region and only one species, S. (S.) nubilus Mulsant, 1850, has been known to exist in Pakistan (Poorani, 2002;Chen et al. 2013). In this paper, another species is described, and a diagnosis of the subgenus with distribution pattern of both species is presented.

Materials and methods
Specimens were collected from different localities in Pakistan during 2015-2016 and were preserved in 85% ethanol. A Zeiss Stemi 305 microscope was used for observing external morphology followed by the dissection of male and female genital structures. After dissection, genitalia were cleared in 10% solution of NaOH and placed in a drop of neutral balsam onto glass slides for further studies.
SteREO Discovery V20 (Zeiss) microscope with an ocular micrometer was used for all measurements, which are presented in millimetres. The following abbreviations are used:

TL
total length from clypeus to apex of elytra, TW total width across both elytra at widest part, TH total height in highest part of elytra, HW head width in widest part including eyes, PL pronotal length across the central area from anterior to basal margin of pronotum, PW pronotal width across widest part, EL elytral length along suture including scutellum, EW elytral width, equivalent to TW.
An AxioCam HRc digital camera attached to the stereoscope, (SteREO Discovery V20) was used for photographs of the whole bodies of beetles. Composite images were generated with AXIO VISION REL. 4.8 software and edited using ADOBE PHO-TOSHOP CC. 2017.
A compound microscope, Olympus BX51 attached to a Coolsnap-Procf & CRI Micro*Color camera was used for the preparation of illustrations of the morphological characters of male genitalia. Morphological terminology of Ślipiński (2007)  Etymology. The species name is derived from Latin (contortum = twisted and tubus = tube) referring to a curved, tube-like apex of penis. Diagnosis. This species is separated by the presence of a stout penis with a curved apex (Fig. 2d) and parameres with long, dense setae on both the apex and inner side ( Fig. 2f-g). In S. (S.) nubilus, the most similar congener, penis is slender (Fig. 3e) and parameres have sparse long setae only at apices (Fig. 3g-h).
Male genitalia: Penis stout (Fig. 2d). Penis capsule with long inner process and short dilated outer one. Apex of penis strongly recurved towards inner side with thread-like appendage. Tegmen stout, with penis guide parallel-sided from base to nearly half length, tapering gradually to a blunt apex in ventral view. In lateral view, penis guide with sides parallel at basal 2/3, then abruptly constricted to pointed apex. Parameres stout; slightly longer than penis guide, with dense, long setae on apical and inner margins (Fig. 2f-g). Female genitalia: Coxites elongate triangular, 2.5 times as long as wide, tapering to blunt apices, each with long terminal setae (Fig. 2h); infundibulum present; spermatheca C-shaped (Fig. 2i) (Fig. 3e-f ). Diagnostic are also: the tegmen stout ( Fig. 3g-h), the penis guide nearly parallel along 2/3 of basal length, converging to pointed apex in ventral view (Fig. 3g), in lateral view abruptly narrowing from apical 1/3 length to apex; parameres with long apical setae (Fig. 3h)