Maculergithus, a new subgenus in Gergithus Schumacher, 1915 with two new species from northern Vietnam (Hemiptera: Fulgoromorpha: Issidae)

The new subgenus Maculergithus subgen. nov. is established to accommodate two new species of the genus Gergithus Stål, 1870 (Issinae, Hemisphaeriini): G. (Maculergithus) tamdao subgen. et sp. nov. and G. (Maculergithus) luteomaculatus subgen. et sp. nov. from Tam Dao National Park in North Vietnam. Two more species from Hainan, China, G. multipunctatus Che, Zhang & Wang, 2007 and G. nonomaculatus Meng & Wang, 2012 are also placed in Maculergithus subgen. nov. A fi fth species from Hainan, yet undescribed and erroneously identifi ed as G. multipunctatus in recent papers also belongs to this new subgenus. Illustrations of habitus, morphological details and male genitalia together with a distribution map and an identifi cation key to the species of Maculergithus subgen. nov. are provided. Four species of the genus Gergithus are now recorded in Vietnam. A rectifi cative note on the misinterpretation of G. multipunctatus in recent publications on Issidae is also provided.


R e s e a r c h a r t i c l e
urn:lsid:zoobank.org:pub:36CCEA4B-B02D-4773-A7A0-687F305CBA8F while Melichar (1906) in his revision of the Issidae stated that Stål's type specimen bears a label "Pulo Penang" (in Malaysia).The genus Ishiharanus was later described by Hori (1969) to accommodate one species originally described from Japan in Gergithus, G. iguchii Matsumura, 1916.The separation of Ishiharanus from Gergithus was based on coloration, the short pronotum and the smooth frons in Ishiharanus.Che et al. (2007) did not follow this view and proposed Ishiharanus as a junior synonym of Gergithus.In recent years, the taxonomic effort concerning the family Issidae allowed the description of 6 species of Gergithus from Taiwan (Chan & Yang 1994), and 11 species from China (Che et al. 2007;Zhang & Che 2009;Meng & Wang 2012).
The study of recently collected material in the framework of our Global Taxonomic Initiative project "A step further in the Entomodiversity of Vietnam" revealed two new species of Gergithus from Tam Dao National Park.Despite the illustrations given by Che et al. (2007) in their description of G. multipunctatus, Chen et al.
(2014) as well as Guo & Chen (2015) mistook the species for another one, as yet undescribed, which does not show the typical yellow round spot on the frons and has very different male genitalia.Hence, the photographs and drawings in both latter papers do not refer to G. multipunctatus but to a new species with frons entirely black-brown on dorsal half and originating from Wuzhishan, Hainan (China).
The present paper aims at describing a new subgenus in Gergithus and two new species from Northern Vietnam belonging to the new subgenus, and to clarify some taxonomic issues concerning Chinese species included in the new subgenus.We also provide an illustrated identification key to the species, and discuss the currently recorded distribution of the subgenus.

Material and methods
The specimens were captured by hand using small transparent vials with which they were slowly covered or collected by sweeping the lower vegetation in the forest.
The genitalia were extracted after boiling the abdomen about one hour in a 10% solution of potassium hydroxide (KOH) at about 100°C.Some drops of saturated alcoholic Chlorazol black solution were added for contrasting (Carayon 1969).The pygofer was separated from the abdomen and the aedeagus dissected with a needle blade for examination.The whole was then placed in glycerine for preservation in a tube attached to the pin of the specimen.
The measurements were taken as in Constant (2004) and the following abbreviations are used: BF = maximum breadth of the frons BTg = maximum breadth of the tegmen BV = maximum breadth of the vertex LF = length of the frons in median line LTg = maximum length of the tegmen LT = total length (apex of head to apex of tegmina) LV = length of the vertex in median line  Che et al. 2007: 611].Type species: Gergithus iguchii Matsumura, 1916 by original designation.
The genus can be separated from other Hemisphaeriini with the key to the genera of Hemisphaeriini proposed by Sun et al. (2012) with the following distinctive set of characters for Gergithus: (1) posterior wing longer than half length of tegmen; (2) frons smooth without median carina or row of tubercles along lateral margin.

Etymology
The name is formed by the combination of "maculatus" (adj., Latin) = spotted and "Gergithus", the genus to which pertains the new subgenus.It is masculine in gender.The subgenus currently contains 4 species, but an undescribed species from Hainan Island (Wuzhishan), illustrated and erroneously referred to as G. multipunctatus in both Chen et al. (2014: 56) and Guo & Chen (2015), also belongs to the group.

Biology
All species seem to live in forested zones of mountainous regions.

Diagnosis
The species can be recognized by the following combination of characters: (1) frons with a yellow spot along dorsal margin; (2) vertex yellow; (3) 2 yellow spots on tegmina along sutural margin; (4) tegmina with 8 yellow spots in total.

Etymology
The species epithet is formed by the juxtaposition of luteus (adj., Latin) = yellow and maculatus (adj., Latin) = spotted.It refers to the yellow spots on the mesonotum and tegmina of the species.

Male genitalia
Pygofer higher than broad and with posterior margin strongly sinuate and roundly projecting in middle in lateral view, and strongly narrowing dorsally (Fig. 4A).Gonostyli longer than high in lateral view (Fig. 4A) with capitulum well developed; capitulum apically laminate and projecting anterointernally; lateral spine of capitulum acute, hooked and projecting anteroventrally; ventroapical margin of gonostyli rounded in lateral view (Fig. 4A, C).Anal tube 1.45 times longer in median line than broad, dorsoventrally flattened and curved ventrally on posterior half; sides broadly rounded and apex truncate in middle (Fig. 4A-B); posterolateral angles projecting posteroventrally (Fig. 4A-B).Aedeagus strongly asymmetrical with ventral lobe of phallobase elongate, parallel-sided, slightly concave internally and roundly truncate apically (Fig. 4D, F).Lateroapical processes of phallobase elongate and spinose, nearly reaching apex of phallus; right process emarginate laterally towards apex (Fig. 4D-F).Left ventrolateral lobe of phallobase laminate and projecting laterally with 3 pointed processes projecting anterolaterally, the median one more developed, and another, more posterior pointed process projecting laterally (Fig. 4D-E).Small hook-shaped lateral process at basal half, on each side (Fig. 4 D-F).Right lateral lobe of phallobase laminate, slightly concave internally (Fig. 4F).

Distribution
Known from Vietnam, Vinh Phuc province, Tam Dao National Park.See map Fig. 1.

Biology
The specimens were collected on lower vegetation, in moist evergreen low mountain forest at an altitude around 1,000 m above sea level.Che, Zhang & Wang, 2007 Figs

Note
The illustrations of the species by Chen et al. (2014) and Guo & Chen (2015) show strong discrepancies when comparing with the original description and accompanying illustrations provided by Che et al. (2007).The specimen illustrated in the two first papers shows a yellow vertex (instead of brown) and frons without yellow spot near dorsal margin.The illustrations of the male genitalia, despite their poor quality in the two first works, also show strong differences, especially obvious in the shape of the ventrolateral lobe of the phallobase which is much larger in Che et al. (2007).Guo & Chen (2015) should not be taken as indicative of the species.

Diagnosis
The species can be recognized by the following combination of characters: (1) frons with a round yellow spot below dorsal margin, not reaching the latter; (2) vertex brown; (3) 4 yellow spots on tegmina along sutural margin; (4) tegmina with 10 yellow spots in total.
Identification can be confirmed by the male genitalia characters illustrated in Che et al. (2007: figs 46-49).

Remark
The mention of the species in Hainan: Wuzhishan by Chen et al. ( 2014) is based on the misidentification of a yet undescribed species and hence erroneous.

Diagnosis
The species can be recognized by the following combination of characters: (1) frons without yellow spot along dorsal margin; (2) vertex yellow; (3) 3 yellow spots on tegmina along sutural margin; (4) tegmina with 9 yellow spots in total.
Identification can be confirmed by the male genitalia characters illustrated in Meng & Wang (2012: figs 16-18).

Diagnosis
The species can be recognized on the following combination of characters: (1) frons with a yellow spot along dorsal margin; (2) vertex yellow; (3) 3 yellow spots on tegmina along sutural margin; (4) tegmina with 10 yellow spots in total.

Etymology
The species epithet refers to the type location, Tam Dao National Park in North Vietnam.It is used as a noun in apposition.
HiNd wiNgS.Brown, unilobed, with veins darker, slightly shorter than tegmina.Venation reticulate with main longitudinal veins distinct basally and numerous cross-veinlets.Costal margin strongly sinuate; sutural margin angularly rounded at mid-length and apical margin rounded.

Male genitalia
Pygofer higher than broad and with posterior margin strongly sinuate and roundly projecting in middle in lateral view, and emarginate dorsally (Fig. 6A).Gonostyli slightly longer than high in lateral view (Fig. 6A) with capitulum well developed; capitulum apically laminate and projecting anterointernally; lateral spine of capitulum acute, hooked and projecting lateroventrally; ventroapical margin of gonostyli rounded in lateral view (Fig. 6A, C).Anal tube 1.5 times longer in median line than broad, dorsoventrally flattened and curved ventrally on posterior half; sides broadly rounded and apex truncate in middle (Fig. 6A-B); posterolateral angles projecting posteroventrally (Fig. 6A-B).Aedeagus strongly asymmetrical with ventral lobe of phallobase elongate, parallel-sided, and roundly truncate apically (Fig. 6D).Lateroapical processes of phallobase elongate and spinose, nearly reaching apex of phallus; right process sinuate internally towards apex (Fig. 6D-F).Left ventrolateral lobe of phallobase laminate and projecting laterally with 2 pointed processes projecting anterolaterally, the dorsal one much more developed, and another more posterior pointed process projecting laterally (Fig. 6D-E).Rather long, spinose lateral process at basal half, on each side, projecting dorsoanteriorly (Fig. 6D-F).Right lateral lobe of phallobase laminate, slightly concave internally (Fig. 6F).

Distribution
Known from Vietnam, Vinh Phuc province, Tam Dao National Park (see map Fig. 1).

Biology
The specimens were collected on lower vegetation, in moist evergreen low mountain forest at an altitude around 1000 m above sea level.-10, 17, 23, 29, 35 [habitus, frons and male genitalia illustrated].

Diagnostic characters
The species can be recognized on the following combination of characters: (1) frons without yellow spot along dorsal margin; (2) vertex yellow; (3) 3 yellow spots on tegmina along sutural margin; (4) tegmina with 10 yellow spots in total.

Discussion
Including the 2 species described in this paper, the genus Gergithus now contains 62 species.The new subgenus Maculergithus subgen.nov. is the first cut proposed inside the genus while it is obvious that other groups of species exist within the genus.As an example, there is a group of new species (Constant unpublished data) very closely related to G. gravidus Melichar, 1906, which Sun et al. 2012;Constant & Pham 2015).It seems worth mentioning that Hainan and Tam Dao are prospected by entomologists on a regular basis and hence it is likely that further exploration of the less known mountains of N Vietnam and SE China (especially Yunnan and Guangdong provinces, and Guangxi autonomous region in China) will reveal a number of additional species.The apparently restricted distribution of the species (see Fig. 1) in Hainan and the fact that species can occur sympatrically (as in Tam Dao) are additional clues which encourage the taxonomic prospection in the region.
This work is licensed under a Creative Commons Attribution 3.0 License.
The list of material examined by Chen et al. (2014) mentions only one male available for genitalia examination.It originates from Hainan, Wuzhishan, rather far from Jianfeng Mountain, the only surely recorded location for G. (Maculergithus) multipunctatus to date.
The concept of G. (Maculergithus) multipunctatus in Chen et al. (2014) and form a very consistent natural group with the latter.The currently known distribution of Gergithus (Maculergithus) is restricted to Hainan Island in SE China and the Tam Dao massif in northern Vietnam.This distribution pattern is similar to the one European Journal of Taxonomy 198: 1-16 (2016) observed in other Issidae like e.g.Pseudochoutagus Che, Zhang & Wang, 2011 (Hainan and Tam Dao -Che et al. 2011; Gnezdilov & Constant 2012) and Neogergithoides Sun, Meng & Wang, 2012 (Hainan, mountains of SE China and mountains of N Vietnam -