First record of the genus Pseudamblyopus (Coleoptera, Erotylidae) in China, with description of a new species

Abstract


Introduction
The family Erotylidae currently contains approximately 3500 species in 258 genera worldwide, with the highest diversity in South America, Africa, and Asia . The tribe Tritomini Curtis, 1834 is the largest tribe in the subfamily Erotylinae sensu stricto, one of six subfamilies in the family Erotylidae, with 92 genera and approximately 1200 species Skelley and Powell 2018). The genus Pseudamblyopus was erected by Araki in 1941 with Amblyopus palmipes Lewis, 1889 as its type species. Until now, only two species, Pseudamblyopus similis (Lewis, 1887) in Japan and Russia and P. palmipes (Lewis, 1889) in Japan, have been reported (Chûjô and Chûjô 1990;Wegrzynowicz 2007). In the Fauna Japonica, Chûjô (1969) described these species in detail. The genus Pseudamblyopus is similar to the genera Amblyopus Lacordaire, 1842 and Scelidopetalon Delkeskamp, 1957. Both Pseudamblyopus and Scelidopetalon can be distinguished from Amblyopus by their small and finely facetted eyes (Araki 1941;Dai and Zhao 2013). While most species of Scelidopetalon differ from those of Pseudamblyopus by having the antennomere XI much wider than long, in Scelidopetalon varicolor (Arrow, 1925) and other species of Pseudamblyopus antennomere XI is almost as long as wide or only slightly wider (Dai and Zhao 2013). The ratio of width to length of the antennomere XI of all species in Pseudamblyopus is 1.2-1.67:1, while Scelidopetalon is 2.1-2.5:1 except S. varicolor. The antennomere XI of S. varicolor is 1.5× as wide as long, which is the same as that in other representatives of Pseudamblyopus. So, S. varicolor (Arrow, 1925) is here transferred to Pseudamblyopus Araki, 1941[Pseudamblyopus varicolor (Arrow, 1925. Pseudamblyopus sinicus sp. nov. from Guangdong Province, China, is described and illustrated. Before this study, there was no record of Pseudamblyopus in China.

Materials and methods
The abdominal segments and the genitalia were detached from the body after softening in hot water. Male and female genitalia were placed in 5% NaOH boiling solution for 5 min and then cleaned with distilled water. Morphological characters were illustrated using a Nikon SMZ800N stereomicroscope and modified with Adobe Photoshop CS6.0. Habitus photographs were taken with an Olympus E-M5II camera. Terminology for major structures follow Lawrence et al. (2010Lawrence et al. ( , 2011. We have examined all specimens of Scelidopetalon and Pseudamblyopus deposited in the Museum of Hebei University (MHBU), Natural History Museum (NHML), and Department of Biology, Shanghai Normal University (SHNU).

Taxonomy
Genus Pseudamblyopus Araki, 1941 Type species. Amblyopus palmipes Lewis, 1889. Diagnosis. Body small to medium-sized, oval to elongate oval, distinctly convex dorsally. Head with a pair of stridulatory files on the occipital region; lacinia without teeth at apex; terminal maxillary palpomere nearly triangular to semicircular; mentum much longer than wide, sharply and triangularly ridged on its surface; terminal labial palpomere elongate but not dilated terminally. Compound eye small and finely facetted; antennae rather short, antennomere III nearly equal in length to antennomere IV and V combined; antennal club compactly articulated, antennomere XI irregularly rounded, almost as long as wide, and much narrower than preceding segment. Pronotum approximately twice as wide at the base as long. The base of pronotum narrower than the base of elytra. Elytra convex, with eight regular rows of fine punctures on each elytron located in bottom of longitudinal furrows (striae). Prosternum rather short, prosternal process wide, widened posteriorly, markedly emarginate at its posterior border. Prosternum with prosternal lines, metaventrite with postmesocoxal lines and basal abdominal ventrite with postmetacoxal lines.
Legs rather short and robust; tibiae markedly expanded terminally. Sexual dimorphism: male with legs more robust than in female, with extended and more dilated protarsi.

Key to species of the genus Pseudamblyopus
Partly based on Arrow (1925) and Dai and Zhao (2013). Diagnosis. Body oval, distinctly convex dorsally, smooth and glossy; general color reddish brown. Pronotum with basal border of pronotum slightly infuscate and one black semicircular spot at basal middle, scutellar shield, elytra, basal border of prosternum, mesoventrite, metaventrite and abdominal ventrites black. Antennomere III slightly longer than antennomeres IV and V combined. Terminal maxillary palpomere triangular, about 1.8× as wide as long. Pronotum nearly trapezoidal, convex dorsally; 1.6× as wide as long, finely and closely punctured. Tibiae strongly expanding at apex.
Comparison. This species is similar to Pseudamblyopus similis due to the shape and color of the body. The new species can be identified using the above key to species. It is distinguished by its pronotum having the black semicircular spot at the basal border; scutellar shield subangulate posteriorly; basal border of prosternum, mesoventrite, metaventrite, and abdominal ventrites black. In contrast to the new species, P. similis has its pronotum without black spot; scutellar shield rounded posteriorly; basal border of prosternum, mesoventrite, metaventrite, and abdominal ventrites reddish brown.
Mesoventrite (Fig. 9) wide, each side with one shallow depression. Metaventrite coarsely punctured at sides and finely punctured in middle; postmesocoxal lines long, extenging to basal 3/5 of metaventrite. Abdomen with coarse and dense punctures laterally and slightly finer ones medially; postmetacoxal lines extending to basal 3/4 of ventrite I.
Legs short, femora dilated medially; tibiae (Fig. 10) subtriangular. Male genitalia (Fig. 11): median lobe weakly curved, gradually narrow from base to apex; median strut long, with apex dilated and about as long as median lobe. Flagellum present and without sclerite at base.
Distribution. China (Guangdong Province). Etymology. The species epithet means Chinese. and suggestions on the manuscript by the reviewers and editor. The authors thank M.V.L. Barclay (Senior Curator in Charge, Coleoptera, Department of Life Sciences) for his assistance during our examination material of Erotylidae at the Natural History Museum.