Revision of the subgenus Orthoscymnus Canepari of Scymnus Kugelann (Coleoptera, Coccinellidae), with descriptions of four new species

Abstract The subgenus Orthoscymnus Canepari, 1997 of Scymnus Kugelann, 1794 is herein revised. Seven species of the Orthoscymnus fauna are recognized, of which four species, Scymnus (Orthoscymnus) jilongicus sp. n., Scymnus (Orthoscymnus) paradoxus sp. n., Scymnus (Orthoscymnus) crispatus sp. n. and Scymnus (Orthoscymnus) duomaculatus sp. n., are described as new to science. Scymnus (Orthoscymnus) rhododendri Canepari is recorded from China for the first time. Scymnus (Pullus) robustibasalis Yu is transferred to the subgenus Orthoscymnus (comb. n.). All species are diagnosed, described and illustrated, and distributions are provided for each species. A key to the species is included.


Introduction
Most members of the family Coccinellidae are important natural enemies of pest, such as whiteflies, aphids, mealybugs, scales and mites, and playing an important role in regulating their populations. Recently, this family was classified in the superfamily Coccinelloidea along with eight other families (Robertson et al. 2015).
The genus Scymnus Kugelann, 1794 comprises eight subgenera and more than 800 species distributed worldwide (Chen et al. 2013(Chen et al. , 2015. In the modern classification, Scymnus has been placed within the tribe Scymnini Mulsant, 1846 in the subfamily Scymninae (Sasaji 1968;Kovář 1996). However, Ślipiński (2007) proposed only two subfamilies, Microweiseinae and Coccinellinae, for the family Coccinellidae, Scymnus was classified in the tribe Coccidulini of the broadly defined subfamily Coccinellinae. This classification was supported by Giorgi et al. (2009) and Seago et al. (2011) based on molecular and morphological studies.
In the present paper, seven species of the subgenus Orthoscymnus are recognized, including four new species described here. Scymnus (O.) rhododendri Canepari, 1997 is newly recorded from China. Scymnus (Pullus) robustibasalis Yu, 2000 is transferred into the subgenus Orthoscymnus based on the characters of the male genitalia, particularly the robust penis capsule. Diagnoses, detailed descriptions and illustrations are provided for each species.

Materials and methods
The morphological terms follow Ślipiński (2007) and Ślipiński and Tomaszewska (2010). Depositories of the type materials are abbreviated as follows: SCAU South China Agricultural University, Guangzhou, China; BAAF Beijing Academy of Agricultural and Forestry Science, Beijing, China; MNHG Museum National d'Histoire Naturelle, Genéve; SMNS Staatliches Museum für Naturkunde, Stuttgart, Germany.
Measurements were made using a micrometer attached to a SteREO Discovery V20 dissecting stereoscope and are defined as follows: (TL) total length, from apical margin of clypeus to apex of elytra; (TW) total width, across both elytra at widest part; (TH) total height, at highest part of elytra; (HW) head width, at widest part including eyes; (PL) pronotal length, from the middle of anterior margin to the base of pronotum; (PW) pronotal width at widest part; (EL) elytral length, along suture from base to apex including scutellum; (EW) elytral width, equal to TW.
Male genitalia were dissected, cleared in a 10% solution of NaOH, and placed on slides for further study. Illustrations of morphological details were made from slide preparations using a camera (Coolsnap-Procf & CRI Micro*Color) attached to an Olympus BX51 compound microscope. After examination, they were transferred to a small card covered with neutral balsam and pinned beneath the specimen. Elytra without brown spot (Fig. 6a); parameres distinctly shorter than penis guide in lateral view (Fig. 6h) Diagnosis. This species can be easily separated from other members of the subgenus Orthoscymnus by having entirely reddish brown body. It is also similar to Scymnus (Pullus) martensi Canepari in general appearance and particularly in the shape of abdominal postcoxal lines, but can be distinguished from it by the much smaller body and the swollen apex of penis bearing short thread-like appendage (Fig. 1f  Head with fine frontal punctures, slightly larger than eye facets, 1.0-2.0 diameters apart. Eyes densely faceted, interocular distance 0.45 times head width. Pronotal punctures as large as those on frons, 1.0-2.0 diameters apart. Surface of elytra with punctures larger than those on pronotum, separated by 2.0-3.0 diameters. Prosternal process trapezoidal, 2 times as long as its width at base; with lateral carinae extending to anterior margin of prosternum, distinctly convergent anteriorly. Abdominal postcoxal lines reaching 3/4 length of abdominal ventrite 1 (Fig. 1d), area enclosed by lines coarsely punctate, narrowly smooth along line. Abdominal ventrite 5 with apex truncate in male. Male genitalia. Penis stout; penis capsule with small and curved inner arm, outer arm large bearing horn-shaped appendage (Fig. 1e); apex of penis distinctly swollen, bearing short thread-like appendage (Fig. 1f). Tegmen stout ( Fig. 1g-h) with penis guide widest at base, gradually tapering to blunt apex in ventral view (Fig. 1g). Parameres longer than penis guide, densely covered with long setae at apices and inner sides (Fig. 1h).
Female externally similar to male but with abdominal ventrite 5 rounded apically. Diagnosis. This species can be separated from other species within the subgenus Orthoscymnus by having a large X-shaped yellow macula on elytra, extending from basal fourth to elytral apex (Fig. 2a). It is also similar to Scymnus (Pullus) testacecollis Kapur in male genitalia, but can be distinguished from it by having slender parameres slightly shorter than penis guide in lateral view (Fig. 2h). In S. (P.) testacecollis, the elytra is black with apical 1/4 testaceous; the parameres are narrow at base and expanding gradually toward apex, nearly as long as penis guide in lateral view (see Kapur 1963 Body elongate oval, slightly convex, dorsum covered with white pubescence (Fig. 2ac). Head, antennae and mouthparts yellowish brown. Pronotum yellow. Scutellum black. Elytra black with large X-shaped, yellow macula at middle, extending to its apex (Fig. 4a). Prothoracic hypomeron yellow. Prosternum brown to black. Mesoventrite and metaventrite black. Elytral epipleuron brown with inner and outer margins black. Legs yellowish brown.
Head with fine frontal punctures, as large as eye facets, 1.0-2.0 diameters apart. Eyes densely faceted, interocular distance 0.51 times head width. Pronotal punctures similar to those on frons, 1.0-1.5 diameters apart. Surface of elytra with punctures much coarser than those on pronotum, separated by 1.0-2.0 diameters. Prosternal process rectangular, 3.5 times as long as its width at base; with lateral carinae parallel, extending to anterior margin of prosternum. Abdominal postcoxal lines reaching 2/3 length of abdominal ventrite 1 (Fig. 2d), area enclosed by lines coarsely punctate, narrowly smooth along line. Abdominal ventrite 5 in male with apical margin shallowly emarginate and ventrite 6 strongly emarginate medially.
Male genitalia. Penis stout and long (Fig. 2e); penis capsule highly sclerotized with short inner arm and large outer arm; apex of penis with membranous appendage (Fig. 2f). Tegmen extremely stout (Figs 2g-h) with penis guide parallel-sided from base to apical 3/4 length, then tapering gradually to pointed apex in ventral view (Fig.  2g), flattened and nearly straight in lateral view (Fig. 2h). Parameres narrow, slightly shorter than penis guide, densely covered with long setae at apices (Fig. 2h).
Female externally similar to male but with apex of abdominal ventrite 5 truncate and ventrite 6 rounded apically. Diagnosis. This species can be easily recognized by its elongate and compressed body and the peculiar characters on male genitalia, particularly the extremely broad, spadeshaped penis guide in ventral view (Fig. 3g). Body elongate oval, slightly convex, dorsum covered with white pubescence (Figs 3ac). Head, antennae and mouthparts yellowish brown. Pronotum yellow. Scutellum black. Elytra black with apical margin narrowly brown. Prothoracic hypomeron and prosternum yellow. Mesoventrite, metaventrite and elytral epipleura black. Legs yellowish brown.
Head with fine frontal punctures, as large as eye facets, 0.5-1.0 diameter apart. Eyes densely faceted, interocular distance 0.47 times head width. Pronotal punctures larger than those on frons, 1.0-2.0 diameters apart. Surface of elytra with punctures much larger than those on pronotum, separated by 2.0-3.0 diameters. Prosternal process rectangular, 5 times as long as its width at base; with lateral carinae parallel, extending to anterior margin of prosternum. Abdominal postcoxal lines reaching 4/5 length of abdominal ventrite 1 (Fig. 3d), area enclosed by lines finely punctate, broadly smooth along line. Abdominal ventrites 5 and 6 in male strongly emarginate apically.
Male genitalia. Penis slender (Fig. 3e); penis capsule highly sclerotized with short inner arm and large outer arm; apex of penis with membranous appendage (Fig. 3f). Tegmen extremely stout (Fig. 3g-h) with penis guide broad, spade-shaped in ventral view (Fig. 3g). Parameres very narrow in lateral view, slightly longer than penis guide, sparsely covered with long setae at apices and inner sides (Fig. 3h).
Female externally similar to male but with black pronotum, abdominal ventrite 5 truncate and ventrite 6 rounded apically. Diagnosis. This species is similar to Scymnus (Orthoscymnus) crispatus sp. n. in general appearance and male genitalia, but can be separated from it by having swollen apex of Body elongate oval, moderately convex, dorsum covered with white pubescence (Figs 4a-c). Head, antennae and mouthparts yellowish brown. Pronotum brown, sometimes with black marking at base. Scutellum black. Elytra black with apical margin narrowly brown. Prothoracic hypomeron and prosternum yellowish brown. Mesoventrite, metaventrite and elytral epipleura black. Legs yellowish brown.
Head with fine frontal punctures, as large as eye facets, 1.0-2.0 diameters apart. Eyes densely faceted, interocular distance 0.42 times head width. Pronotal punctures larger than those on frons, 1.0-2.0 diameters apart. Surface of elytra with punctures much coarser than those on pronotum, separated by 2.0-3.0 diameters. Prosternal process trapezoidal, 2 times as long as its width at base; with lateral carinae extending to anterior margin of prosternum, distinctly convergent anteriorly. Abdominal postcoxal lines extending nearly to posterior margin of abdominal ventrite 1 (Fig. 4d), area enclosed by lines finely punctate, broadly smooth along line. Abdominal ventrites 5 and 6 in male strongly emarginate apically.
Male genitalia. Penis stout (Fig. 4e); penis capsule highly sclerotized with tiny inner arm and large outer arm; apex of penis distinctly swollen with membranous appendage at apical 1/5 length (Fig. 4f). Tegmen stout (Figs 4g-h) with penis guide wide, with sides subparallel from base to its apical 3/4 length, then tapering gradually to pointed apex in ventral view (Fig. 4g), and its apex slightly curved outwardly in lateral view (Fig. 4h). Parameres constricted at base with expanded apex, distinctly shorter than penis guide, sparsely covered with long setae at apices (Fig. 4h) Diagnosis. This species is similar to Scymnus (Orthoscymnus) rhododendri in male genitalia, but can be distinguished from it by the elongate oval parameres (Fig. 5h) and the narrow, sub-triangular penis guide in ventral view (Fig. 5g). Body elongate oval, moderately convex, dorsum covered with white pubescence (Fig. 5a-c). Head yellow. Antennae and mouthparts yellowish brown. Pronotum yellow. Scutellum black. Elytra black with apical margin narrowly brown. Prothoracic hypomeron yellow. Prosternum brown. Mesoventrite, metaventrite and elytral epipleura black. Legs yellowish brown.
Head with fine frontal punctures, as large as eye facets, 0.5-1.0 diameter apart. Eyes densely faceted, interocular distance 0.43 times head width. Pronotal punctures slightly larger than those on frons, 1.0-2.0 diameters apart. Surface of elytra with punctures much larger than those on pronotum, separated by 2.0-3.0 diameters. Prosternal process trapezoidal, 4 times as long as its width at base; with lateral carinae extending to anterior margin of prosternum, distinctly convergent anteriorly. Abdominal postcoxal lines extending nearly to posterior margin of abdominal ventrite 1 (Fig. 5d), area enclosed by lines finely punctate, broadly smooth along line. Abdominal ventrite 5 strongly emarginate and ventrite 6 weakly emarginate apically in male.
Head with dense frontal punctures, slightly smaller than eye facets, 0.5-1.0 diameter apart. Eyes densely faceted, interocular distance 0.50 times head width. Pronotal punctures as large as those on frons, 1.0-1.5 diameters apart. Surface of elytra with punctures much larger than those on pronotum, separated by 1.0-2.0 diameters. Prosternal process trapezoidal, 2 times as long as its width at base; with lateral carinae extending to anterior margin of prosternum, slightly convergent anteriorly. Abdominal postcoxal lines reaching 3/4 length of abdominal ventrite 1 (Fig. 6d), area enclosed by lines finely punctate, broadly smooth along line. Abdominal ventrites 5 and 6 in male strongly emarginate apically.
Body oval, moderately convex, dorsum covered with white pubescence (Fig. 7a-c). Head black. Antennae and mouthparts dark brown. Pronotum and scutellum black. Elytra black with two kidney-shaped brown spots near suture. Underside entirely black. Legs dark brown.
Head with fine frontal punctures, as large as eye facets, 0.5-1.0 diameter apart. Eyes densely faceted, interocular distance 0.5 times head width. Pronotal punctures larger than those on frons, 1.0-2.0 diameters apart. Surface of elytra with punctures larger than those on pronotum, separated by 1.0-2.0 diameters. Prosternal process trapezoidal, 2 times as long as its width at base; with lateral carinae extending to anterior margin of prosternum, distinctly convergent anteriorly. Abdominal postcoxal lines extending nearly to posterior margins of abdominal ventrite 1 (Fig. 7d), area enclosed by lines finely punctate, broadly smooth along line. Abdominal ventrite 5 truncate and ventrite 6 strongly emarginated apically in male.
Male genitalia. Penis slender (Fig. 7e); penis capsule sclerotized with small inner arm and large outer arm; apex of penis slightly sinuated with membranous appendage (Fig. 7f). Tegmen stout (Fig. 7g-h) with penis guide parallel-sided from base to 3/4 length, then tapering gradually to blunt apex in ventral view (Fig. 7g). Parameres curved at base, expanded toward apex, slightly longer than penis guide, sparsely covered with long setae at apices (Fig. 7h).
Female externally similar to male but with abdominal ventrites 5 and 6 rounded apically.
Distribution. China (Tibet). Etymology. The species name is derived from Latin ('duo-' = two and 'maculatus' = maculate), referring to two brown spots on the elytra.