Revision of Chinese mainland Hybovalgus Kolbe , 1904 , with description of a new species , and Excisivalgus Endrödi , 1952 reduced to synonymy with Hybovalgus ( Coleoptera : Scarabaeidae )

The genus Hybovalgus Kolbe, 1904 is represented by eight species on the Chinese mainland, many of which also inhabit northern Vietnam and Laos. Species of Hybovalgus are endemic to this area, and to the island of Taiwan. Until now, there is a lot of confusion in our knowledge of Hybovalgus on mainland China, due to erroneous descriptions of new species by European entomologists and incorrect identifications of specimens by local entomologists. Study of more material and many types has clarified this situation by better defining the species, synonymizing some of them, describing one new species, Hybovalgus calvus sp. nov. and recognizing the fact that females of two species were included in the new genus Excisivalgus Endrödi, 1952, which is here synonymized with Hybovalgus.


Introduction
processed with photo stacking software (Zerene Stacker, Version 1.04 Build T201411272115; http:// www.zerenesystems.com). Finally, in order to increase clarity, backgrounds were removed from photos using GIMP 2.8.14.
We refer to Ricchiardi & Li (2015) for some morphological terms.
Photographs of the mating couple and types of Hybovalgus tonkinensis were taken with a Canon EOS 5D Mark III and MP-E 65mm f/2.8 1-5× lens (see Fig. 2).
The following abbreviations are used to denote specimen depositories:

Hybovalgus versicolor
A key for each sex of Chinese mainland Hybovalgus is included in this work.

Diagnosis
In the years after 1904 some entomologists tried to better define Hybovalgus (Arrow 1944;Paulian 1961;Krikken 1978;Miyake 1985), but could not find even one morphological synapomorphy. Krikken (1984) and Miyake (1985) wrote that the shape of the parameters was peculiar to Hybovalgus. Miyake (1985) distinguished Hybovalgus from Dasyvalgus as follows: "Parameres more or less prolonged, not confluent each other, with a excision on each inner edge, Hybovalgus. Parameres vestigial, sometimes confluent each other, Dasyvalgus". The paramere shape of each genus is different, and easily distinguishable, although the meaning given to the word "vestigial" by Miyake is not clear.
After studying many specimens (including all the species of Hybovalgus in Taiwan), we conclude that the males of Hybovalgus can be distinguished from those of Dasyvalgus by a series of non-exclusive characters and by the shape of the parameres (Fig. 3A-F). The special shape of Hybovalgus parameres is distinctive compared with the variable parameres of males of Dasyvalgus species. This paramere shape, that we define as "Hybovalgus shape", within the Chinese Valgina is shared only with Dasyvalgoides denticulatus Endrödi, 1952, in a monotypic genus. The relationship between these two genera must still be investigated, but the latter species is readily distinguishable from any Hybovalgus by the protibia with six teeth; and from H. sexdentatus by its flattened body with inconspicuous scales tufts.
The series of non-exclusive characters that separate Hybovalgus from the other Oriental Valgina genera are: -Protibial external teeth 1-3 long and sharp in males, where tooth 2 is sometime a bit shorter than 1 and 3; the same for females but often they are worn by digging (see remarks on page 7 about differences between the two sexes) and in some cases tooth 2 is slightly shorter than 1 or 3 ( Fig. 1).
-Suctorial brush long in males, short in females (Ricchiardi & Li 2015). See remarks below about differences between the two sexes.
-Anterior margin of clypeus noticeably sinuate in both sexes, a bit less in females of H. thibetanus.
-Pronotal lateral margins more or less crenate in both sexes.
-Pronotal lateral margin depression always present in both sexes.
-Pronotal posterior margin of most females (but not all) more or less excavated.

RICCHIARDI E. & LI S., Revision of Chinese mainland Hybovalgus
-Protibia with five teeth on the external margin, in one case six (H. sexdentatus).
-Pygidium of males always narrowed from the middle to the apex; apex rounded in caudal view, not prominent in lateral view. Pygidium of females often (but not always) modified at apex (see Remarks under species accounts below).
-Pygidium of males with a ventral small, flat or slightly hollowed surface with posterior margin rounded or pointed at center. In females this area is bigger and deeply hollowed.
-Propygidial scale tufts of females darker than those of males.
Some species have protibial teeth 1-2 and/or 3-4 closer to one another than to the others. This character is not consistent among all the specimens of Hybovalgus as it varies within the same species. European Journal of Taxonomy 340: 1-32 (2017) Another character that we decided not to use for the separation of species is the presence or absence of cretaceous maculae on the propygidium or pygidium of males. In some species those maculae are really difficult to see because they are covered with thick scales or by the built-up body grease.

Identification of females
Generally, it is easy to separate females from males because the pronotal posterior margin is more or less deeply excavated (

Variability of paramere shape
After analysis of the males of a many Valgina belonging to hundreds of species, we concluded that the study of the shape of the parameres is a reliable way to define species. There are, however, a couple of notable exceptions. Jameson & Swoboda (2005), revising the New World Valgina, wrote that: "However, one species of New World valgine, Valgus seticollis Beauvois, 1807, has extremely variable male genitalia although there is an overall similarity in pattern" (Jameson & Swoboda 2005: figs 31-35); "Other characters that we examined are consistent within this species, including form of the tarsomeres, pygidial spine, pronotum, sternites, and spiracles. Lacking other morphological characters to separate the genitalic forms, we conservatively group all the forms as one species. A thorough study of the genitalic forms of V. seticollis would be an excellent topic for a molecular analysis and could reveal interesting evolutionary patterns". Kolbe (1897) described a new Valgina genus, Homovalgus, to include Valgus seticollis. Jameson & Swoboda (2005) clarified the nomenclature of the species and placed it under Valgus. It is our opinion that because the shape of the parameres is similar to that of Hybovalgus/Dasyvalgoides, and the lack of a pygidial stylus in females, this species must be separated from Valgus and that its valid name is Homovalgus seticollis. The relationships of this species to the Oriental Valgina could add appeal to further study.
In the Oriental Region, another species, Hybovalgus fraternus, is a similar case to that of Homovalgus seticollis. Hybovalgus fraternus also exhibits limited variation in morphology and great variation in paramere shape. This is why we decided to conservatively avoid splitting this species merely on the basis of variation in paramere shape. Figure 3 shows several examples of the aedeagus of Chinese Hybovalgus species along with some nomenclature. The outline of the aedeagus is distinctive. The phallobase is always V-shaped ventroapically (vs) and with a sclerotized upper anterior part (spb) notched, flat or pointed, sometime variable within the same species. The parameres are prominent, with the apex extended and with different shapes, with or without a sub-apical external or internal tooth; basal lobe more or less developed and in some cases variable in shape within a species. In lateral view the parameres shows a more or less deep, basomedial notch (bmn).  (Nonfried, 1891). C. H. tonkinensis Moser, 1904. Proposed nomenclature of Hybovalgus aedeagus: aap = anterior apex of phallobase; ap = apex of parameres; bl = basal lobe; bmn = baso-medial notch; etp = sub-apical external tooth of parameres; iml = internal medial lobe; itp = sub-apical internal tooth of parameres; ma = membrane of aedeagus; pb = phallobase; spb = sclerotized upper anterior part of phallobase; vs = V-shaped ventro-apically membranous region of aedeagus. Drawings: grey parts: parameres; white parts: phallobase.

Distribution
Hybovalgus species are mostly distributed in south-central continental China, with most species extending to northern Laos, northern Vietnam, Hainan Island (5-6 species) and Taiwan. In Taiwan there are six species: Hybovalgus kamiyai (Sawada, 1941); H. major Sawada, 1939;H. matsudai Miyake, 1985;H. obsoletosquamosus Miyake, 1985;H. takasagoensis (Sawada, 1941) and H. thoracicus Moser 1911. These six Taiwanese species are considered endemic, but their relationships with continental Hybovalgus must still be analyzed. Figure 4 shows the approximate distribution of Hybovalgus species. In the west, the genus inhabits Yunnan and Sichuan (there are no records so far for Myanmar). In the east some species reach Shandong, Jangsu and Zhejiang. In the north there are extensions into the southestern part of Palaearctic China (sensu Chen et al. 2008). We found no records of Hybovalgus from Henan and Anhui provinces or Chongqing Municipality, but this may be due to a lack of collecting.

Hybovalgus bioculatus
Hybovalgus bioculatus -Schenkling 1922: 51. -Ma 1995 fig. 168  Remarks Kolbe (1904: 57) wrote that the locality where Fruhstorfer collected the type series was at 2-3000 m, but this is incorrect, as the original labels bears the mention " 2-3000' " (' = feet). In fact, the highest point of Montes Mauson is actually 1541 m (5249'). Many, or all of the specimens of H. bioculatus preserved at MNHUB and ERC most probably belong to the H. bioculatus type series, but they were not labelled as such by Kolbe who wrote "Eine Anzahl Exemplare". Scanning the literature dealing with H. bioculatus, we concluded that the female of this species was never described and probably Kolbe himself failed to pair the two sexes. This is clear because one of the specimens (ERC) is a female (described below), and Kolbe wrote on one small label "keine Forceps" without recognizing it as female.

Description of a female from Montes Mauson (ERC; type locality of the species)
MeasureMents. Length 8.0 mm; width 5.1 mm. Body colour mostly castaneous.
Head. Black, slightly shiny, covered with large, round punctures each with a bristle-like, erect, testaceous scale. Clypeus black, with anterior margin castaneous, anterior margin sinuate, suctorial brush shorter than that of male.
PronotuM. Black, nearly glabrous, trapezoidal, slightly crenate at sides, laterally depressed at center of lateral margins; anterior angle acute, posterior angle obtuse, apical margin rounded with a small ridge inclined at approximately 45°; posterior margin with central part deeply excavated as an enlarged "E" (Fig. 5F); carinae rounded, parallel, ending around middle of disk; central small carina not present; lateral carinae obsolete; with 2 testaceous, barely noticeable, central carina scale tufts; with 2 more or less noticeable, small, scales tufts at posterior angle.
elytra. Castaneous, slightly shiny, mostly glabrous, with shallow, black juxtascutellar depression, the anterior half of which is surrounded by a prominent ridge; humeral humbones prominent, with a small, testaceous scale tuft; anteapical umbones slightly prominent, with a prominent testaceous scale tuft directed posteriorly. Part of disk black, with thick, small, recumbent, barely noticeable scales.
ProPygidiuM. Castaneous, slightly shiny, nearly glabrous, with scattered, small, recumbent black scales; posterior margin curved inward at middle, with 2 prominent, black propygidial scale tufts. Cones at posterior margin short and blunt. PygidiuM. Black, wider than long, slightly shiny, nearly glabrous, covered with scattered, small, recumbent, black scales; narrowing to apex, where there is a prominent rounded projection, showy in lateral view. Ventrally with a hollowed surface, glabrous and posteriourly semicircular. Apex with a prominent, testaceous scale tuft.
Mesoand MetafeMur. Castaneous with a small, testaceous scale tuft at centre of posterior margin.
Metatibia. Castaneous, centrally enlarged, without a tooth at center of posterior margin. First metatarsomere long, twice length of second.

Species variability
Males Length 7.7-8.5 mm; width 4.5-5.1 mm. The colour of the body is stable. Along posterior border of pygidium, in the places where Valgina often have scale tufts, H. bioculatus sometimes shows a glabrous surface, while in other specimens there are small, thick, erect scales whose colour varies from testaceous, to dirty testaceous to blackish. Lastly, in Chinese specimens the two posterior margin propygidial scale tufts and humeral humbone scale tufts are dirty testaceous instead of testaceous. Two of the three specimens from Guangxi have the basomedial notches of the parameres closed.

Females
The only two known females do not show any significant variation.

Flight period
The adults of this species were collected from mid-April to early June at an elevation of 700-1900 m.

Distribution
Hybovalgus bioculatus was described from northern Vietnam. New records reported here came from northern Laos and China (Hainan, Guangxi).
Hybovalgus calvus sp. nov. urn:lsid:zoobank.org:act:2AE1E317-E510-4210-B843-973C1985BF3E Fig. 6 Diagnosis Hybovalgus calvus sp. nov. can easily be separated from all other Chinese Hybovalgus (except from H. jordansi) by the V-shaped protrusion at the posterior margin of the pronotum (Fig. 6A, D, J). The female pygidium apex lacks a protrusion. The parameres are different from those of H. bioculatus in the C-shaped apex (Fig. 6H). Females of Hybovalgus calvus sp. nov. can be distinguished from those of H. jordansi by the prominent testaceous scale tufts at the posterior margin of the pronotum; by the fringe of small, testaceous scales at the pygidial apex, instead of prominent, double-pointed testaceous scale tufts. The apex of the parameres of both species (Figs 6H, 8I) are inwardly C-shaped, but in H. jordansi they are thinner and tapered.

Etymology
The name comes from the Latin word "calvus", meaning glabrous, as the integument of this species appears at first glance. body. Colour mostly black, with propygidium and pygidium dark castaneous. Head. Black, slightly shiny, covered with large round punctures; frons and vertex covered with small, recumbent, testaceous scales that do not form scale tufts. Clypeus black, anteriorly sinuate, suctorial brush long.

Holotype
PronotuM. Black, nearly glabrous, trapezoidal, slightly crenate at sides, laterally depressed at center of lateral margins; anterior angle acute, posterior angle right-angled, with apex rounded; posterior margin with central part showily produced backwards, V-shaped, with apex rounded. Carinae rounded, parallel, ending around middle of disk; central small carina not present; lateral carinae not present; with 2 testaceous barely noticeable central carina scale tufts; without any other scale tufts. Covered with small, decumbent, scattered, testaceous scales.
ProPygidiuM. Dark castaneous, covered with thick, decumbent, small, coffee bean shaped, testaceous scales that form two small propygidium scale tufts; centre of posterior margin depressed; cones short and blunt.
PygidiuM. Dark castaneous, wider than long, slightly depressed at sides in ventral half. Covered with thick, decumbent, small, coffee grain shaped, testaceous scales which form a fringe of long scales at apex. Apex rounded, without projection. Under apex, in ventral view, there is a hollowed, semicircular, glabrous, horizontal surface.
Mesoand MetafeMur. Black, with a fringe of small, testaceous scales at centre of posterior margin which do not form a small scale tuft.
Metatibia. Black, centrally enlarged at posterior margin, without a tooth at centre. First metatarsomere long 1.8 times the length of second.
The female is quite similar to the male, not showing great differences in the shape of the posterior margins of the pronotum or pygidium apex. The first is pointed at the apex, the latter is regularly rounded. The propygidium is much wider than long, shaped as in the male but with a small depression close to each superior corner.

Flight period
The Vietnamese types were collected from May to early June at an elevation of 700-1500 m. Moser, 1915 Fig. 7 Hybovalgus fraternus Moser, 1915: 603.

Remarks
The analysis of many males from northern Vietnam, northern Laos and China shows that, despite the great variability in paramere shape (particularly the size of the basomedial notch and basal lobe, but many males show intermediate dimensions), there is otherwise little morphological variation within males: the black posterior corner and carina posterior scale tufts are sometimes reduced or barely noticeable. The size of males varies from 5.4 mm (width 3.5 mm) to 6.8 mm (width 4.3 mm). Sometimes the elytra scale pattern is reduced (Fig. 7A), but it is unclear if this is due to wear or real pattern variability.
One female (ERC) from Guizhou was collected at the same locality and date as three males and its general aspect and all the morphology allows it to be assigned to H. fraternus. This female can be separated from the male by the posterior margin of the pronotum slightly excavated as an enlarged 'C', the apex of the pygidium prominently pointed.
Many males of H. fraternus were collected by J. Klapperich in April 1938 near Kuatun (Guadun, Fujian, 29°37′46″ N, 117°40′01″ E). At least one of these males (HNHM) was collected on the same day (20 April) and at the same locality as the type series of Excisivalgus csikii Endrödi, 1952. The morphology of the HT of E. klapperichi csikii being identical to the Guizhou H. fraternus female, we concluded that Excisivalgus csikii Endrödi, 1952 is a junior synonym (♀) of Hybovalgus fraternus Moser, 1915. The two females are larger than the males. The female from Fujian (HT of E. csikii) is 7.3 mm long and 4.2 mm wide, while the one from Guizhou (ERC) is 6.9 mm long and 4.5 mm wide.

Flight period
Adults of H. fraternus were collected from the first days of April to the beginning of June, at an elevation of 700-2300 m.

Distribution
This species was described from northern Vietnam. Records from Laos and China (Fujian, Zhejiang, Sichuan, Guangxi, Hunan, Guizhou, and Jiangxi) are new. Moser, 1904

Remarks
The female is unknown.
The specimens from Hainan have the pronotum, elytron and legs darker, sometimes nearly black. One specimen from Laos has the scales on the propygidium and pygidium darker. In general all scale tufts are small to barely noticeable.

Flight period
Hybovalgus fulvosquamosus adults appear in Vietnam and Laos between April and June. Instead, all Chinese specimens were collected in July. Collected between 500 and 1500 m.

Distribution
Described from northern Vietnam. New records are from Laos and China (Guangdong, Hunan and Hainan). (Endrödi, 1952), comb. nov.

Remarks
This species was described by Endrödi (1952) as Dasyvalgus jordansi Endrödi, 1952. Having its parameres clearly of the same shape as in Hybovalgus (Fig. 8I-J), we include this species in the latter genus (new combination).
The female is unknown.

Species variability
Hybovalgus jordansi shows little morphological variation, but varies in size (length 5.6-6.5 mm; width 3.3-3.9 mm). In some specimens the posterior half of the lateral margin of the pronotum narrows in a straight line from the middle to the posterior corner; in other specimens it narrows in the same way, but noticeably arched inwards. The latter is a morphological character used by Miyake (1985) as a main character in his key to Taiwanese Hybovalgus species, but it seems like an unstable character to separate the continental species of the genus.

Flight period
Adults of H. jordansi were collected from the end of March to the end of April.

Remarks
According to Arrow (1944), the type series comprised three specimens, all from Laos. In his work Arrow seemed not to realize that one of the types was a female, as he described only the male. Paulian (1961), applying the International Code of Zoological Nomenclature, amended the name of this species from H sex-dentatus (Arrow, 1944) to H. sexdentatus, but Bacchus (1974) erroneously misspelled the name of the species again and designated the type series of three specimens, LT, one PLT male and one PLT female, but did not describe the latter, which remained undescribed until now. In this work we restate that the hyphen must be eliminated as the correct name is H. sexdentatus, and give the differences between sexes.

Identification of female (from the ♀ at ERC)
The size of females is more or less the same as that of the biggest males and the shape of the posterior margin of the pronotum is simply rounded, without protrusions or excavations. The protibia external margin has six teeth, as in the male.
At first glance the female can be distinguished by the pygidium shape: its apex is protruding and pointed (Fig. 8D).

Species variability
The length of males varies from 4.7 to 7.5 mm; the width from 3.0 to 4.1 mm. The only female known so far is 7.4 mm long and 3.5 mm wide.
The study of 148 specimens leads to the conclusion that the species is morphologically slightly variable. In males the only variations observed are: -Propygidial scales and scale tufts testaceous or whitish.
-The scales on the elytron are sometimes black and testaceous, sometimes black and whitish.
-The legs are black or castaneous. -On occasion, protibia teeth 3-4 and 5-6 are closer to one another than to 1-3.

Flight period
Specimens were collected between mid-March and the first week of June at an elevation comprised between 160 and 1900 m.

Distribution
Hybovalgus sexdentatus was described from Laos and recorded by Ma (1995) from Yunnan. New records reported here are from northern Vietnam and China (Guangxi, Hainan, Sichuan). One specimen is labelled as from Shandong (Jaozhou Bay), but this record is doutbful without further finds. (Nonfried, 1891) Fig. 9

Type material
Note: all types here designated have a red type label. Alla data reported are copied from specimen labels.

Males
In most specimens the legs are black, but in a few they are castaneous. The same is true for the propygidium and pygidium. The scales on the propygidium and pygidium vary in colour, from light testaceous to dark testaceous (see Fig. 9A-D). Sometimes the last visible sternites and the anal sternite are glabrous instead of covered with thick scales. The size of males is variable: length from 5.7 to 7.6 mm; width from 3.5 to 4.2 mm.

Females
The colour of the integuments and scales varies in the same way as in males. The same with size: length from to 5.8 to 8.3 mm; width from 3.3 to 4.0 mm.

Flight period
Specimes were collected between the end of March and early June. Some specimens are labelled as having been collected in September and October (see list of studied material), but these records must be confirmed by other finds. Specimens have been collected from 700 to 2000 m.

Distribution
Hybovalgus thibetanus is endemic to continental China and inhabits most of the central provinces: Yunnan, Sichuan, Jiangsu, Shaanxi, Jiangxi, Hubei, Gansu and Zhejiang. The absence from the other central provinces of China (Guizhou, Hunan, Anhui and Henan) is probably due to a lack of collecting. Hybovalgus thibetanus seems to be absent from the southern Chinese Provinces; we have no records from Guangxi, Guangdong, Hainan or Fujian.
The name of this species, "thibetanus", is from ancient collecting when the northernmost parts of Yunnan were considered to be part of Tibet. To date, there are no specimens of this species known to us collected in Myanmar, Arunachal Pradesh or the southern Xizang valleys, but the presence of H. thibetanus there is possible (see Fig. 10, which shows the distribution of H. thibetanus in Yunnan's valleys close to Myanmar's borders). Moser, 1904 Fig. 11 Hybovalgus tonkinensis Moser, 1904: 272. Excisivalgus klapperichi Endrödi, 1952: 63 syn. nov. Paralectotype (here designated) VIETNAM: 1 ♂, same data as LT (MNHUB).

Male
Males are variable, even in size (length 6.9-9.2 mm, width 3.8-5.2 mm). The pygidium of males has a double pointed testaceous scale tuft at the apex, rarely reduced to a fringe of scales. The small scales that cover the propygidium and pygidium vary from testaceous to whitish. The abdomen varies from nearly glabrous to covered with whitish scales at the sides. The posterior half of the pronotal lateral margin varies from slightly indented to slightly arched outwardly. The interteguments of some specimens from Zhejiang are castaneous instead of black, with the pronotum darkened at the anterior and posterior margins; one specimen from the same Chinese province shows black pronotal posterior margin scale tufts (as, in general, is the case in females) instead of testaceous. The parameres do not vary much in shape.

Female
Females show variable scale patterns on the elytra (Fig. 11E-I). Furthermore, the colour of the small scales covering the propygidium and pygidium varies from dirty testaceous (sometimes somewhat orange) to black. Less variable in size than males, generally constantly greater, but not attaining the size of the bigger males (female length 8.2-8.6 mm, width 4.9-5.2 mm).

Flight period
Adults were captured from early April to mid-June, at elevations from 300 to 1600 m.

Distribution
Described from northern Vietnam. New records are from China (Fujian, Zhejiang, Jangxi, Guangxi, Hunan, Guizhou, Hainan, Gansu and Sichuan). New finds are necessary to better define the distribution of H. tonkinensis in Sichuan and Gansu. The absence of reports from Yunnan is probably due to a lack of research.

Discussion
The purpose of this paper is to clarify and redescribe the species composition of Chinese Hybovalgus, assign to it several species previously belonging to other Valgina genera, establish several new synonyms, and provide a more detailed distribution of species. Lastly, one new species from Hainan and northern Vietnam, Hybovalgus calvus sp. nov., is described.
One of the main problems in identifying specimens for study is that many (old or recently collected) are discoloured due to a buildup of grease. In such cases, determining the colours or presence/absence of scales is critical and any misinterpretation could lead to an incorrect identification. This is why in this work the pattern of scales on the body was not highlighted.
In general, the form of the parameres for determination is reliable, with the exception of H. fraternus that shows broad morphological variation.
The determination of Hybovalgus females (females of six of eight Chinese Hybovalgus are known) is now easier thanks to several distinct morphological characters here presented.