Melichergithus Constant & Pham 2024, gen. nov.
Creators: name: Constant, Jérôme
name: Pham, Hong Thai
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hemiptera
Issidae
Melichergithus

description: Genus Melichergithus gen. nov.
urn:lsid:zoobank.org:act: 2E9A4553-3DE8-417A-A9AE-223EE7FC544C
Type species
Gergithus gravidus Melichar, 1906 by present designation.
Diagnosis
Melichergithus gen. nov. can be differentiated from all other genera of Hemisphaeriini by the following combination of characters:
(1) the hind wings unilobous, slightly shorter than the tegmina but not rudimentary;
(2) the strongly rounded costal margin of the tegmina (in dorsal view) and very convex body making the insect strongly hemispherical;
(3) the frons nearly wider than long in midline, smooth, without carina;
(4) the three transverse black lines on the ventral side of the pro- and mesofemora;
(5) the colour pattern of the tegmina which are either entirely black or black with yellow marking on disc of and with several, alternate black and yellow concentric lines along the costal margin;
(6) the pygofer without spine on posterior margin;
(7) the asymmetrical aedeagus with a lateral laminate process on each side of the periandrium.
Differential diagnosis
The most similar genera are Ishiharanus Hori, 1969, Ceratogergithus Gnezdilov, 2017 and Maculergithus Constant & Pham, 2016.
Melichergithus gen. nov. can be separated
(1) from Ishiharanus by its much wider frons (0.85 times as long in midline as wide; 1.1 time as long as wide in Ishiharanus) and by the lateral laminate processes of the periandrium (absent in Ishiharanus);
(2) from Ceratogergithus by the absence of a spine on the posterior margin of the pygofer (always present in Ceratogergithus species) and by the lateral laminate processes of the periandrium (absent in Ceratogergithus);
(3) from Maculergithus by the very different colour pattern, never dark brown/black with numerous bright yellow round spots (always dark brown/black with numerous bright yellow spots in Maculergithus), the pattern of the pro- and mesofemora with 3 transverse black bands ventrally (black bands absent in Maculergithus) and by the lateral laminate processes of the periandrium (absent in Maculergithus).
Etymology
The name of the new genus is formed from the combination of ‘Melich-’, reminiscent of Leopold Melichar (1856–1924) who described the type species Gergithus gravidus in his monograph on Issidae (Melichar 1906), and ‘ -ergithus ’ to remind that the genus, like Gergithus, belongs to the group of Hemisphaeriini with rather long hind wings. The gender is masculine.
Description
MEASUREMENTS. Rather large (5–6 mm), very convex, round-bodied Hemisphaeriinae.
COLOUR. Variable with 2 main morphs (legs always with characteristic pattern as described below): (1) black and bright yellow, with yellow transverse bands on frons, yellow marking on disc of tegmen and several, alternate black and yellow concentric lines along costal margin of tegmina; (2) black, with one yellow transverse band along frontoclypeal suture.
HEAD. Vertex strongly broader than long in midline, weakly concave; anterior margin weakly curved, posterior one concave. Frons convex, wider than long in midline, smooth; maximum breadth slightly under level of antennae. Clypeus convex, smooth; anteclypeus convex but without defined median carina. Labium with last segment longer than broad, shorter than penultimate. Antennae with scape short, ring-shaped, and bulbous pedicel.
THORAX. Pronotum wider than head, short, slightly less than 3 times as short as mesonotum in midline; disc with 2 impressed points; paranotal lobes with rounded lateroventral angle. Mesonotum triangular, smooth with weak transverse carina parallel to anterior margin and shallowly impressed point along lateral margins at midlength; without longitudinal carinae.
TEGMINA. Strongly convex, minutely punctured, and with rounded lateral margins in dorsal view (making the insect look hemispherical); nearly as wide as long when taken together in dorsal view; apical margin rounded; venation weakly distinct, with longitudinal veins marked as blunt ridges.
HIND WINGS. Slightly shorter than tegmina, unilobed. Venation reticulate with main longitudinal veins distinct basally (C, ScP+R, MP, CuA), and numerous cross-veinlets. Costal margin sinuate; sutural margin rounded at midlength and apical margin rounded.
LEGS. Rather elongate and slender, with pro- and mesofemora dorsoventrally flattened, ventrally with 3 contrasting black transverse markings and black line along anterior margin; pro- and mesotibiae slender with black line along outer margin; pro- and mesotarsi rather elongate; metatibiae with 2 lateral spines in distal half and 6 apical spines. Metatarsi rather short with first segment about as long as combined length of remaining segments. Metatibiotarsal formula: (2) 6 / 8 / 2.
MALE TERMINALIA. Pygofer short, about 3 times as high as long at mid-height in lateral view, with posterior margin rounded in lateral view. Gonostyli convex, with posterior margin rounded in lateral view; capitulum rather short, with a wide neck with basal hump on posterior margin, with apical tooth directed mesad and lateral laminate process at mid-height. Anal tube dorsoventrally flattened, wide in dorsal view and with anal opening in basal half. Aedeagus asymmetrical, strongly curved in lateral view. Ventral lobe of periandrium laminate and with lateral processes; lateral lobes of periandrium laminate, covering base of lateral elongate processes of periandrium. Connective well developed, corpus connective long, regularly and rather weakly curved in lateral view, tectiductus well developed, conical with wide anterior foramen.
Distribution
China: Guangxi; Vietnam: provinces of Cao Bang, Hanoi, Ha Tinh, Hai Phong, Hoa Binh, Lang Son, Ninh Binh, Phu Tho, Quang Ninh, Thai Nguyen, Thanh Hoa and Vinh Phuc.
Note
The record from Hai Phong Province is based on specimens which were collected in Cat Ba Island (in RBINS and VNMN), and that from Cao bang Province on specimens from Pia Oac National Park (in MNHN). All are females that cannot be identified to species level, which must be based on male terminalia examination, hence, they might represent undescribed species.
Species included
Melichergithus gravidus (Melichar, 1906) gen. et comb. nov.
description: Published as part of Constant, Jérôme & Pham, Hong Thai, 2024, Sixteen issid planthopper species in one day in Dong Son-Ky Thuong Nature Reserve in North Vietnam: Eight new species, one new genus and additional new records (Hemiptera: Fulgoromorpha: Issidae), pp. 1-87 in European Journal of Taxonomy 919 (1) on pages 26-28, DOI: 10.5852/ejt.2024.919.2407, http://zenodo.org/record/10559520