First record of the genus Dialarnaca Gorochov, 2005 from China, with description of two new species (Orthoptera, Gryllacrididae, Gryllacridinae)

Abstract In the present paper, Dialarnaca Gorochov, 2005 is recorded from China for the first time, with two new species of the genus described, Dialarnaca longicerca Shi & Bian, sp. n. and Dialarnaca zhoui Shi & Bian, sp. n. A key and a distribution map of the genus Dialarnaca, are provided.


Introduction
Dialarnaca was first proposed by Gorochov (2005) with Dialarnaca roseola (type locality: Philippines, Mindoro Island, near Puerto Galera). Currently, except for the type species, no additional species was described (Eades et al. 2015). In this paper, the genus Dialarnaca is first recorded from China and two new species, Dialarnaca longicerca sp. n. (type locality: Hainan, Changjiang, Bawangling) and Dialarnaca zhoui sp. n. (type locality: Yunnan, Jinping, Pinghe), are described. A key to species and a distribution map are provided.

Material and methods
Specimens in this study were collected from tropical area of southern China. Morphological structures were examined and measured using Leica M205A stereomicroscope. Leica DFC 450 digital imaging system was used to obtain morphological images. The map was drawn using ArcGIS 10.2 based on the occurrence points. The specimens were deposited in the Museum of Hebei University, China.
All measurements of length are in millimetres. The following abbreviations were used for the specimen measurements: body w/wings -the distance from the apex of fastigium verticis to the apex of tegmina; body w/o wings -in male, the distance from the apex of fastigium verticis to the posterior margin of tenth abdominal tergite, in female, the distance from the apex of fastigium verticis to the apex of epiproct; pronotum -the straight-line distance from the anterior margin of pronotum to posterior margin; tegmen -the distance from the base of tegmen to apex; hind femur -the distance from the base of hind femur to the apex of genicular lobe; ovipositor -the distance from the base of subgenital plate to the apex of ovipositor.

Type species. Dialarnaca roseola
Description. Body medium, form slender. Eyes kidney-shaped, prominent; ocelli small, inconspicuous. Humeral sinus of pronotum distinct. Tegmina and hind wings developed, far surpassing apices of hind femora; M vein of tegmina simple, free, not united with R vein. Fore coxae with one small spine; fore and middle femora unarmed on ventral surface, tibiae with five pairs of movable ventral spines (including a pair of apical spines); middle tibiae with an inner apical spine on dorsal surface. Hind femora with two rows of minute spines on ventral surface; tibiae with two rows of spines on dorsal surface, subapices with 1 pair of spines on ventral surface, apices with one pair of dorsal spines, the inner one obviously longer than outer one, and two pairs of ventral spines. Second and third abdominal tergites with two rows of transverse stridulatory teeth on lateral margins separately. MALE: ninth abdominal tergite without any hook, centre of posterior margin with a large tubercular process, the angular apex of which slightly directing downwards; tenth abdominal tergite in the form of transverse sclerite, posterior area projecting backwards, membranous, the apex with 1 pair of heavily sclerotized hooks, which curved upwards; subgenital plate variable with well-developed styli; genitalia entirely membranous. FEMALE: posterior area of seventh abdominal sternite projecting backwards; basal area of subgenital plate with numerous rugulae.
Diagnosis. The genus can be identified by the following characters: male ninth abdominal tergite without any process, posterior area of tenth abdominal tergite membranous with one pair of sclerotized apical hooks, which curved upwards. Because only one female is known, the diagnosis of the genus is insufficient.  Gorochov, 2005 in body green, male cerci longer and apical area curled, posterior margin of male subgenital plate slightly concave in the middle, styli shorter.

Key to the species of
Description. Male. The following characters are in addition to those given in the generic description. Fastigium verticis broad, about 1.5-1.7 times as wide as scape (Fig.  2). Eyes ovoid; ocelli inconspicuous. Scape about as long as length of eyes, pedicel approximately half as long as scape (Fig. 2). Anterior margin of pronotum projected in the middle, posterior margin almost truncate, lateral lobes longer than high (Figs 1, 3). Hind femora with 5-6 spines on internal margin of ventral surface, external margin with 6-8 spines; tibiae with 5-6 spines on internal margin and seven spines on external margin of dorsal surface. Apical area of ninth abdominal tergite with 1 tubercular process in the middle, which slightly directing downwards; posterior margin of tenth abdominal tergite with one pair of long triangular hooks in the middle, which curved upwards, its apices directing forwards (Figs 4-6, 18-19). Cerci about 4.3-4.4 mm, longer than in other species of the genus, apical area curly, apices obtuse (Fig. 5). Subgenital plate broader than long, anterior margin nearly straight, posterior margin slightly concave in the middle; styli about 0.23-0.24 mm, shorter than in other species of the genus, cylindrical, located on lateral margins of subgenital plate near apex (Fig. 4).
Coloration. Body green. Eyes black-brown. Apices of hooks of tenth abdominal tergite blackish.
Female. This species is known only from the holotype. Coloration. Body reddish yellow. Labrum yellow, eyes brown, ocelli yellow. Spines of all legs black.

Distribution. China (Yunnan).
Etymology. This species is named in honour of Dr. Shan-Yi Zhou who provided much assistance in collecting specimens.