A taxonomic study of the genus Panesthia (Blattodea, Blaberidae, Panesthiinae) from China with descriptions of one new species, one new subspecies and the male of Panesthia antennata

Abstract One new species Panesthia guizhouensis sp. n. and one new subspecies Panesthia stellata concava ssp. n. are described and illustrated. The male of Panesthia antennata Brunner von Wattenwyl, 1893 and its brachypterous form are described and illustrated for the first time. Panesthia strelkovi Bey-Bienko, 1969 is redescribed and illustrated. Three known species, Panesthia birmanica Brunner von Wattenwyl, 1893, Panesthia sinuata Saussure, 1839 and Panesthia angustipennis cognata Bey-Bienko, 1969 are illustrated. In addition, a key to all species of the genus Panesthia from China is presented.


Introduction
The wood-feeding cockroach genus Panesthia was established by Serville (1831), belonging to the subfamily Panesthiinae of the family Blaberidae. Brunner von Wattenwyl (1893) presented 16 species and Saussure (1895) recorded 33 species in this genus.  described three species of this genus from China. More recently, Roth (1977Roth ( , 1979 recognized 55 species and nine subspecies of Panesthia worldwide, of which 15 species and two subspecies were reported for the first time. In this latter work, Roth also stated that P. angustipennis spadica by Bey-Bienko (1950) from mainland China should be P. angustipennis cognata. From then on, no new valid taxon in this genus was published. Asahina (1988) established the subspecies P. angustipennis yayeyamensis, which was split from the subspecies P. angustipennis spadica; but Maekawa et al. (1999) disagreed with his view based on molecular data. Feng and Woo (1990) reported two species from China, i.e., P. concinna Feng & Woo, 1990 and P. guangxiensis Feng & Woo, 1990; the former had been synonymized with Salganea taiwanensis Roth, 1979, while the latter was transferred to Salganea (Wang et al., 2014). At the same time, they also recorded P. birmanica, P. sinuata and P. stellata as distributed in China. Up to now, there were 55 species and nine subspecies of Panesthia reported worldwide, including eight species and two subspecies from China.
In this paper, we report one new species and one new subspecies, and also provide a key including nine species and three subspecies of the Panesthia from China. We also take this opportunity to report the male and the brachypterous form of P. antennata for the first time.

Materials and methods
The terminology of the head, body and male genitalia used in this paper mainly follows Roth (1977Roth ( , 1979Roth ( , 2003. Measurements are based on materials examined. Measurement of body length is without the tegmen. The genital segments of the examined specimens were macerated in 10% NaOH and observed in glycerin jelly using a Motic K400 stereomicroscope. All drawings were made with the aid of a Motic K400 stereomicroscope. Photographs of the specimens were made using a Canon 50D plus a Canon EF 100mm f/2.8L IS USM Macro lens with the aid of Helicon Focus software. We considered adults and nymphs collected from the same colony with similar external characters to be one species. Nymphs were identified mainly based on markings on the mesonotum and metanotum as well as their holes in terga, lateral margin of terga and hind margin of supra-anal plate. Type specimens are deposited in the Institute of Entomology, Southwest University, Beibei, Chongqing, China (SWU) and the Museum of Hebei University, Baoding, Hebei Province, China (HBU). We also borrowed specimens from the Museum of Southwest Forestry University, Kunming, Yunnan Province, China (SWFU) and Dali University, Dali, Yunnan Province, China (DLU) as indicated. Taxonomy   Family Blaberidae Brunner von Wattenwyl, 1865  Subfamily Panesthiinae Kirby, 1904 Genus Panesthia Serville, 1831 Panesthia Serville, 1831: 38;Princis 1965: 309;Roth 1977Roth : 12, 1979 Diagnosis (mainly following Roth 1977Roth , 1979. Coloration dark reddish brown or black. Size ranging from 15 mm to over 50 mm. Body strongly sclerotized with a coarse surface, densely covered with punctations. Vertex foveolar or not, slightly exposed. Pronotum transversal ovate, anterior margin slightly convex, with a variable excision in the midline, or entire. If excised, the corners of the concavity protruding or not. Lateral margins of pronotum arched and the hind margin almost straight or slightly concave. The surface of the pronotum granular on variably depressed anterior half with a pair of oblique grooves and often with two disc tubercles on the posteriorly punctate half. Tegmina and wings unicoloured or not, fully developed (sometimes mutilated terminally or only leaving the basal portion of the tegmina and wings), or reduced, or tegmina reduced but wings absent, or both tegmina and wings absent. The tarsi of legs with five segments, pulvilli are present on segments 1-4. The hind metatarsus is shorter than the remaining segments combined. Claws symmetrical, without arolia. Abdominal terga with punctate surface, and the hind margins without spines, tubercles or teeth. Anterolateral corners of terga rarely with holes and without setae, or just tergum six (T6) and tergum seven (T7) with holes. Lateral margins of T6 smooth, and laterocaudal angles not produced, or with a spine and directed caudally. Lateral margins of T7 straight and not crenulate, laterocaudal angles sometimes produced and usually directed caudally. Lateral margins of sternite seven (S7) with a feeble and short ridge or without ridge. In the male, the hind margin of the last sternite is truncate or concave, and the subgenital plate is slightly exposed. In the female, the hind margin of the last sternite is convex and rounded. Both sexes are without styli. Supra-anal plate punctate, with uneven or rounded hind margin, and cerci are short and broad basally. Paraprocts are asymmetrical, the left one in ventral view with a finger-like projection lacking in the right one. Anterior margin and lateral margins of subgenital plate concave and the hind margin is rounded. Four genital phallomeres as follow: first sclerite of the left phallomere (L1) plated; second ventromedial sclerite of left phallomere (L2vm) rodlike; second dorsal sclerite of the left phallomere (L2d) variable; second sclerite of the Remarks. The genus Panesthia is recognized by both T6 and T7 having smooth lateral margins, their hind margins without tubercles; the hind angles of T7 spine-like, but T6 not. Some species in this genus may have individuals with mixed characters resembling the genus Salganea Stål, 1877, Ancaudellia Shaw, 1925or Miopanesthia Saussure, 1895(Roth 1982. The first two genera can be distinguished from Panesthia by the anterolateral angles of terga usually with holes or grooves with associated setae, but species of Panesthia often lack holes, or if with holes in T6 and T7, the holes without setae. The last genus Miopanesthia, has a hind metatarsus that is usually close to or longer than the combined length of the remaining tarsal segments; however, the hind metatarsus is shorter than the remaining segments in Panesthia. Distribution. Oriental Region, Australian Region, a few locations in the Palaearctic Region (China, Japan). Hind margin of supra-anal plate entire dorsally or weakly undulate; median phallomere L2d elongate, tapering to a round apex (Roth 1979: Figs   Vertex punctate, with a small foveola in dorsal view, which is exposed to the excision of pronotum in anterior margin (Fig. 27). Face punctulate, ocelli distinct. Pronotum transverse, anterior margin with a U-shaped excision in the middle, lateral corners of the indentation incrassate and upturned; lateral margins convex and the widest point below the middle; hind margin straight; anterior 1/3 of pronotum weakly depressed and the floor granular, with two rounded grooves, remaining surface punctate and with two tu- bercles medially (Fig. 27). Tegmina and wings fully developed (Figs 28-29) and reaching or extending beyond the end of abdomen (Fig. 1), sometimes mutilated. In brachypterous form, tegmina and wings reduced (Figs 37-38) with tip just reaching the hind margin of segment two to segment four of abdomen (Fig. 5), sometimes mutilated terminally. Caudal edge of the hind wing wave-shaped (Fig. 38). Anterior ventral margin of front femur with 0-2 spines and distal spine absent, hind margin with a large distal spine. Abdominal tergites densely punctate, the punctations denser caudally, anterolateral corners without holes. Caudal angles of T6 rounded; lateral margins of T7 smooth, posteriolateral angles extended caudally and with subacute apex (Fig. 30). Abdominal sternites densely punctate, hind margin of S7 concave (Fig. 31) and subgenital plate slightly exposed. Supraanal plate densely punctate, the surface coarser than on abdominal tergites; hind margin crenulate, with 7-10 small teeth in middle, caudal angles small, similar to or slightly bigger than the largest one between them (Fig. 32). Cercus fin-shaped, setaceous ventrally, dorsal surface without setae (Fig. 32). Posterior part of subgenital plate flabellate (Fig. 33).
Female. Similar to male, but hind margin of S7 rounded. In all specimens observed, the anterior margin of pronotum with an excision. In brachypterous form, tegmina and wings also reduced similar to males.
Female. Essentially similar to male, differs with the anterior margin of pronotum weakly concave as well as S7 with rounded hind margin.
Nymph. Body black and punctate, with a broad yellow band on the mesonotum which extends to the middle of the metanotum, hind border of the mark concave (Figs 11-12).
Remarks. This subspecies is close to P. stellata stellata Saussure, 1895, but can be distinguished by the following characteristics: 1) nymph with broad yellowish band on mesonotum and metanotum, nymph of P. stellata stellata with two yellowish markings on mesonotum and without markings on metanotum; 2) anterior margin of pronotum with an excision in both sexes and the corners of the excision upturned in male; anterior margin of pronotum entire or slightly concave in both sexes of P. stellata stellata. Feng and Woo (1990) identified the material collected by Fusheng Huang as P. stellata Saussure, 1895. But after our critical examination, it should be treated as a new subspecies.
Etymology. The subspecific epithet is derived from the Latin word "concavus" which refers to the hind margin of the yellowish mark on nymphs being concave.
Vertex slightly punctate, exposed (Fig. 49). Face punctulate, ocelli small, round. Pronotum transverse ovate and flat; anterior margin convex or straight, center weakly concave, lateral corners of the indentation slightly incrassate and upturned; lateral margins convex and widest at or before the midline; hind margin straight; anterior 1/3 of pronotum shallowly depressed and delineated by two grooves, the surface sparsely granular; posterior half flattened and punctate densely, with two small disc tubercles (Fig. 49). Tegmina and wings well developed (Figs 50-51), extending to or surpassing the tip of abdomen (Fig. 13), few reaching to the hind margin of 6 th tergite, sometimes mutilated terminally. Anterior ventral margin of front femur with 0-1 spine and with a small distal spine, hind margin with a large distal spine. Abdominal tergites punctate, with punctations denser caudally, anterolateral corners without holes. Caudal angles of 6 th tergite weakly extended; lateral margins of 7 th tergite smooth, caudal angles acute and directed caudally (Fig. 52). Abdominal sternites punctate, hind margin of the 7 th sternite weakly concave and subgenital plate exposed (Fig. 53). Supra-anal plate punctate densely, hairless, hind margin smooth or slightly concave in the middle in dorsal view, with 5-7 small teeth medially or smooth in ventral view, caudal angles small (Fig. 55). Cercus fin-shaped with acute apex, dorsal surface without setae and hairy ventrally (Fig. 54). Hind margin of subgenital plate rounded (Fig. 55).
Female. Differs from male as follows: the anterior margin of pronotum weakly concave and the corners not upturned; the tubercles on surface smaller than in male. Hind margin of S7 rounded.
Nymph. Body black and punctuate, with two yellowish brown marks on the mesonotum and metanotum without marks (Figs 15-16).
Remarks. This species is similar to P. angustipennis spadica, but can be distinguished by the following characteristics: 1) anterior margin of pronotum weakly concave in male, and without mesal elevation, male of latter with anterior margin broadly excised and with mesal elevation; 2) body length < 30 mm in most, or few surpassing 30 mm, body length of P. angustipennis spadica > 30 mm.
Etymology. The specific epithet is named after the locality of the holotype, Guizhou Province.
small spine in the each hind angle, T7 with relatively large posteriolateral angles, with apexes acute and directed to the terminus (Fig. 61). Abdominal sternites equally punctate. Lateral margins of S7 oblique and protruded medially; hind margin straight (Fig.  62) and subgenital plate marginally exposed. The surface of supra-anal plate uniformly covered with large round punctations; hind margin with 5-7 small subacute teeth medially; the lateral teeth with acute apexes are larger than the teeth between them (Fig. 63). Cercus fin-shaped and pointed apically, swollen and hirsute in venter, but hairless dorsally (Fig. 63). Anterior angles of subgenital plate tapering to subacute apexes (Fig. 64).
Material examined. Two males, China: Hainan Prov., Mt. Diaoluo, 12 May 1965, coll. Sikong Liu;one male, China: Hainan Prov., Mt. Jianfengling, 17 April 1982, coll. Zhiqin Chen. (SWU) Distribution. China (Hainan). Figs 19-20, 68-73 Panesthia birmanica Brunner, 1893: 54;Roth 1979: 67;Feng and Woo 1990: 213. Remarks. This species is distinguished from other species by its small body length, ranging from 22.5 mm to 28 mm; and also by pronotum virtually flattened, anterior margin slightly thickened, entire or weakly indented in male, entire and not thickened in female (Fig. 68); as well as the caudal angles of T7 acute and posteriorly directed (Fig. 71); hind margin of supra-anal plate smooth or slightly crenulate, with the lateral teeth acute in apexes (Fig. 73); anterior ventral margin of front femur with 0-3 spines and with small distal spine, and posterior ventral margin with a large distal spine. The caudal angles of T6 sometimes with an acute spine separately may confuse this species with species in the genus Miopanesthia, but can be distinguished by the shorter hind metatarsus, as stated in the genus remarks. Roth (1979)  Remarks. This species is similar to P. angustipennis spadica, but can be distinguished by body length (19-29 mm), which is commonly smaller than the latter (34-42 mm).

Panesthia birmanica Brunner von Wattenwyl, 1893
In male of P. sinuata, the anterior margin of pronotum is broadly concave and the corners of the indentation upturned (Fig. 74), while the latter is merely concave and without corners in small individuals about 34 mm. The anteroventral margin of front femur often bears 0-1 spine in P. sinuata, but more than two spines in P. angustipennis spadica. Roth (1979) described this species as similar to P. antennata, but the male of the latter had no mesal elevation of the anterior margin of pronotum.  (Figs 74-78), 0.5 mm (Figs 79-83).

Discussion
Gregarious, xylophagous cockroaches of the blaberid genus Panesthia exhibit little variation in morphology. They have dark, hard, rigid and pitted exoskeletons. Body sizes range from 15 mm to over 50 mm. They usually live in decaying wood, fallen leaves, rubbish, cracks in rocks, or in some kind of debris, and feed on wood (Feng and Woo 1990). Members of Panesthia cribrata live not only inside decaying logs but also under logs (Rugg and Rose 1989). During our collection in Guizhou Province in August, 2013, we obtained a colony of P. guizhouensis sp. n. from rotten wood near a large pool, comprised of 52 adults and at least 60 nymphs of different instars. When the wood was split, all of them fled away quickly (Wang X.D., pers. obs.). Nymphs of P. angustipennis spadica have two morphs. One has a pair of large reddish spots on mesonotum (Roth 1979: Fig. 20B) and is from Taiwan, China and Yayeyama Island, Japan. The other is uniformly colored without spots on mesonotum (Roth 1979: Fig. 20A) and is from Taiwan and Japan except Yayeyama Island. Asahina (1988) separated P. angustipennis yayeyamensis from P. angustipennis spadica in view of the nymph having a reddish marked mesonotum. Maekawa et al. (1999) analyzed the molecular phylogenetic relationships of Salganea and Panesthia based on the COII gene. P. angustipennis yayeyamensis formed a monophyletic clade, which was embedded in the clade of P. angustipennis spadica; this suggests P. angustipennis yayeyamensis should be returned to P. angustipennis spadica. After examination of a large quantity of nymphs of P. angustipennis, we think it is not reasonable and adequate to accurately distinguish subspecies only according to the difference in marks of the nymph. For example, there are also different nymph morphs in P. angustipennis angustipennis (Roth 1979: Figs 2B-K). Therefore, we hereby agree with the decision by Maekawa et al. (1999) that P. angustipennis yayeyamensis should be treated as the synonym of P. angustipennis spadica.
Panesthia is the only genus of the subfamily Panesthiinae in which several species and subspecies have tegmina and wings which are fully developed or variably reduced (Roth 1982), i.e., include wing polymorphic species. There are five species and four subspecies of Panesthia with variable reduction of tegmina and wings in both sexes (Roth 1982). From a P. antennata, which was recorded with mutilated tegmina and wings, Roth (1979) inferred that a developed winged morph may have existed. But after checking specimens collected from Yunnan Province, we have identified and discovered 15 males and eight females of P. antennata with tegmina and wings about or beyond the end of abdomen, and 11 males and five females with tegmina and wings apparently short, only reaching between the second segment and the fourth segment of the abdomen. Given the above, P. antennata can also be treated as a wing polymorphic species.
The reason for wing polymorphism in cockroaches is still unknown. Roth (1977Roth ( , 1979 observed that some species of Panesthia with reduced-wing forms were not commonly collected. We record 16 adult specimens of P. antennata in brachypterous form collected (39 specimens in all). To be unambiguous, this brachypterous form does not just occur by accident or gene mutation in rare specimens, but rather in large numbers. Species with both macropterous and brachypterous forms possess a higher fitness (Roff, 1986) and this seems reasonable in Panesthia as well. However further investigation will be required to confirm this reasoning.