A new species of the genus Euxaldar Fennah, 1978 (Hemiptera, Fulgoromorpha, Issidae) from China and revision on the molecular phylogeny of the family Author Yang, Liang-Jing https://orcid.org/0000-0001-6631-406X Institute of Entomology, Guizhou University, Guiyang, Guizhou, 550025, China & The Provincial Special Key Laboratory for Development and Utilization of Insect Resources, Guizhou University, Guiyang, Guizhou, 550025, Chinas & Office of Academic Affairs, Liupanshui Normal College, Liupanshui, Guizhou, 55300, China Author Chang, Zhi-Min https://orcid.org/0000-0002-7247-9706 Institute of Entomology, Guizhou University, Guiyang, Guizhou, 550025, China & The Provincial Special Key Laboratory for Development and Utilization of Insect Resources, Guizhou University, Guiyang, Guizhou, 550025, Chinas & College of Animal Science, Guizhou University, Guiyang, Guizhou, 550025, China Author Yang, Lin Institute of Entomology, Guizhou University, Guiyang, Guizhou, 550025, China & The Provincial Special Key Laboratory for Development and Utilization of Insect Resources, Guizhou University, Guiyang, Guizhou, 550025, Chinas Author Chen, Xiang-Sheng Institute of Entomology, Guizhou University, Guiyang, Guizhou, 550025, China & The Provincial Special Key Laboratory for Development and Utilization of Insect Resources, Guizhou University, Guiyang, Guizhou, 550025, Chinas chenxs3218@163.com text ZooKeys 2021 2021-03-01 1021 19 35 http://dx.doi.org/10.3897/zookeys.1021.35510 journal article http://dx.doi.org/10.3897/zookeys.1021.35510 1313-2970-1021-19 DE22C8781AE5479884B58FCB4A37A73B 771FE3A67E005B12BCAE02CD0B8E31B7 Euxaldar daweishanensis sp. nov. Figs 1-7 , 8-17 , 19-26 Type material. Holotype : ♂ , China : Yunnan Province , Pingbian County , Mt : Daweishan National Nature Reserve ( 23°07'N , 103°20'E ), 8 August , 2017, Qiang Luo , Nian Gong, Y. -J Sui, Yan Zhi. Paratypes : 7♂♂ 36♀♀ , same data as holotype . Measurements. Total length (from apex of coryphe to tip of forewing): male 4.1-4.3 mm ( N = 6), female 4.6-4.9 mm ( N = 10); forewing length: male 3.8-4.0 mm ( N = 7), female 4.2-4.4 mm ( N = 10). Diagnosis. This species differs from other Euxaldar species by the following characters: (1) coryphe about 2.3 times wider than long (less, or more than 2.3 times as wide as long in other species of Euxaldar ); (2) first metatibiotarsal of hind leg with 8 intermediate spines (other species of Euxaldar with first metatarsomere of hind leg with 6 or 7 intermediate spines); (2) penis with 3 different ribbon-shaped processes at middle (Figs 16 , 17 , pp, paed), dorsal lobe of periandrium with 2 asymmetrical sword-shaped subapical processes in apical half (Figs 16 , 17 , sap) (other species without sword-shaped subapical processes in apical half of dorsal lobe of periandrium). Figures 1-7. Euxaldar daweishanensis sp. nov. (adult) 1 male dorsal view 2 male lateral view 3 female dorsal view 4 female lateral view 5 male genitalia, lateral view 6 penis, left lateral view 7 penis, right lateral view. Scale bars: 0.5 mm . Coloration. Male body brown yellowish, with irregular dark brown bands on forewings. Coryphe brown (Fig. 8 ). Metope with all margins, pustules, and median carinae pale yellow, disc dark brown (Fig. 9 ). Metopoclypeal suture light yellow. Anteclypeus straw yellow. Postclypeus pale yellow (Figs 9 , 10 ). Rostrum and antenna straw yellow (Fig. 10 ). Eyes dark brown (Figs 8-10 ). Pronotum straw yellow. Mesonotum dark brown (Fig. 8 ). Forewings slightly hyaline, with 2 irregular brown bands (Figs 1 , 2 , 11 ): a large one derived from costal margin to almost C2 of radial cell, small one derived from apical half of median cell, extended to areola postica (anterior cubital area). Legs (Figs 2 , 4 ) light brown. Abdomen brown, male genital segment light straw yellow. Females generally darker than males (Figs 3 , 4 ). Figures 8-18. Euxaldar daweishanensis sp. nov. (male adult) 8 head and thorax, dorsal view 9 face, front view 10 head and thorax, lateral view 11 forewings 12 hind wing 13 anal tube, dorsal view 14 pygofer, anal tube and genital style, lateral view 15 capitulum of gonostyli, dorsal view 16 penis, lateral view (left) 17 penis, lateral view (right) 18 penis, ventro-apical view. Abbreviations: aed -aedeagus; bp -basal process of the periandrium; dllp -dorso-lateral lobe of periandrium; paed -process of aedeagus; pp -process of periandrium; sap -subapical processes of periandrium; vlp -venteral lobe of periandrium. Scale bars: 0.5 mm Head and thorax. Coryphe transverse, about 2.3 times wider than long, anterior margin weakly prominent in the middle, posterior margin angularly concave (Fig. 8 ). Metope flat, median carinae weak, running from upper margin and reaching middle, with a row of distinct pustules along lateral margins, disc with weak pustules (Fig. 9 ). Metopoclypeal suture complete (Fig. 9 ). Anteclypeus with distinct median carinae (Figs 9 , 10 ). Pronotum with disc depressed (Fig. 8 ). Mesonotum about 2.1 times longer than pronotum. Forewings (Figs 1-4 , 11 ) with distinct claval suture and CuP venation, the other venation reticulate, poorly recognizable. Hind wings about 0.7 times as long as forewings, venation reticulate (Fig. 12 ). Hind tibiae with 2 lateral teeth. Metatibiotarsal formula (9-8)-8-2. Male genitalia. Anal tube (Fig. 13 ) enlarging from base to apical fourth in dorsal view, narrowing to apex, apical margin convex in the middle, laterally with 2 small triangular processes in apical fourth. Pygofer with hind margin distinctly convex (Figs 5 , 14 ). Gonostyli triangular, hind margin convex, caudo-dorsal angle rounded (Fig. 14 ). Capitulum of gonostyli style with wide and short neck, with a wide lateral tooth and 2 apical teeth (Figs 14 , 15 ). Corpus of connective rod-like (Figs 5-7 , 16 , 17 ), curved, cuticularized, reaching middle of periandrium; tectiductus of connective cup-shaped, third ventral part separated from corpus (Fig. 14 ). Periandrium asymmetrical (Figs 6 , 7 , 16 , 17 ), suspensorium V-shaped in dorsal view, membranaceous in the middle; base with process claval (Figs 16 , 17 , bp), dorsal periandrium lobe with 2 ribbon-like processes in center near right edge (Figs 16 , 17 , pp), directed dorsad, respectively curved caudad and cephalad; dorsal lobe in left lateral view with 2 subapical processes near apex (Fig. 16 , sap): one crescent-shaped, above base with another process shortly sword-shaped, directed caudad; in right lateral view (Fig. 17 , sap) with two subapical processes derived from apical third, directed apically, one process base movable, sword-shaped, below base another process crutch-like and sclerotized. Ventral periandrium lobe (Fig. 18 , vlp) with apical margin convex, shorter than dorso-lateral lobe of periandrium (Figs 16 , 17 , dllp, 18) in ventral view. Aedeagus (Figs 16 , 17 , aed) with dagger-shaped process, base slightly movable, directed dorsad, slightly inclined caudad (Figs 16 , 17 , paed). Figures 19-26. Euxaldar daweishanensis sp. nov. (female adult) 19 female anal tube, dorsal view 20 sternite VII, ventral view 21, 22 gonocoxa VIII and gonapophysis VIII, ventral view 23 gonapophysis IX and gonaspiculum bridge, dorsal view 24 gonapophysis IX and gonaspiculum bridge, lateral view 25 gonoplacs, lateral view 26 gonoplacs, dorsal view Abbreviations: lf -lateral field of posterior connective lamina of gonapophyses IX; mdp -medial dorsal process; mf -medial field of posterior connective lamina of gonapophyses IX; pvd -posterior ventral lobes; slf -sublateral field of posterior connective lamina of gonapophyses IX. Scale bars: 0.5 mm . Female genitalia. Anal tube ovate in dorsal view, about 1.3 times longer than maximal width at second part (Fig. 19 ). Anal style long, located at basal fifth of anal tube. In ventral view, Sternite VII with hind margin convex medially, without any process in ventral view, disc arched ventrad (Fig. 20 ). Anterior connective lamina of gonapophysis VIII nearly rectangular, with 3 or 4 apical teeth on inner lateral margin and 3 lateral teeth bearing 3 keels on outer lateral margin (Figs 21 , 22 ); endogonocoxal lobe developed, membranous in distal part (Figs 21 , 22 ). Posterior connective lamina of gonapophyses IX triangular in dorsal view (Fig. 23 ), narrowing; median field with leaf-like process bearing apical margin, deeply incised in the middle (Fig. 23 , mdp); lateral field (Fig. 23 , lf) without obvious process; distal parts of laminae (Fig. 23 , slf) with tooth-like process on each lateral margin; posterior ventral lobes bent at slender angle (Figs 23 , pvb, 24). Gonoplacs in lateral view irregularly elliptical (Fig. 25 ), without carinae, with apical half fused, apical margin membranous (Fig. 26 ). Etymology. This new species is named after the type locality, Mt. Daweishan National Nature Reserve , Yunnan Province , China . Distribution. China ( Yunnan Province ) Remark. This new species resembles Euxaldar jehucal but differs from the latter by the following combined features: Anal tube with apical margin convex in the middle, lateral margin with a small triangular process in each side (anal tube wide, apical margin deeply concave medially in E. jehucal ); periandrium with two asymmetrical subapical processes sword-shaped in apical half (periandrium with subapical processes not as sword-shaped in E. jehucal ); aedeagus with one medial dagger-like process on lateral margins (aedeagus without any processes on lateral margins in E. jehucal ). Phylogenetical analysis. Four gene fragments of Euxaldar daweishanensis sp. nov. were sequenced and registered in GenBank with the accession numbers as follows: MK 441660 ( COI ), MK 426664 ( 16S ), MK 441661 ( Cytb ), MK 441662 ( 28S d6-d7). Nucleotide compositions are listed in Table 3 . A+ T content of 16S is the highest (76.0%) and 28S (d6-d7) is the lowest (39.2%). This study deals with more molecular markers from Oriental and Western Palaearctic, Nearctic and Neotropical regions than previous reviews by Wang et al. (2016) and Gnezdilov et al. (2020) . BI (Fig. 27 ) and ML (Fig. 28 ) topologies were mostly congruent, and the monophyly of Issidae was reconfirmed. The Issidae had lower support in the ML tree ( BS : 47) than Gnezdilov et al. (2020) and Wang et al. et al. (2016) and higher support in the BL analysis ( PP : 88). Subfamilies Hysteropterinae Melichar, 1906 sensu ( Gnezdilov et al. 2020 ) and Issinae Spinola, 1839 sensu ( Gnezdilov et al. 2020 ) are both recovered (nodes 1 and 2: ML : 47, 67; BI: 88, 89, respectively). Table 3. Nucleotide gene composition of Euxaldar daweishanensis Yang, Chang & Chen, sp. nov.

Gene	A%	T %	G%	C%	A+ T %
COI	33.2	36.3	17.8	12.7	69.5
16S	27.4	48.6	14.9	9.1	76.0
Cytb	35.3	34.5	11.6	18.6	69.8
28S d6-d7	20.4	18.9	33.7	27.0	39.2

Node 1 includes almost all tribal level genera group of the subfamily Hysteropterinae sensu Gnezdilov (2016a , b , 2020) and the tribe Thioniini Melichar, 1906 sensu ( Gnezdilov 2018 ): 1) Node 4 ( ML : 75, BI: 100) corresponds to the subtribe Thioniina sensu Gnezdilov (2018) with the inclusion of American taxa, characterized by hind wings reduced or rudimentary, A2 vein branched; 2) Nodes 5 and 6 corresponds to the monophyletic Kervillea , and Mycterodus genera group sensu Gnezdilov (2016 a, b); monophyly of the Hysteropterum genera group was not supported by this analysis (node 3). Node 2 ( ML : 67, BI: 89) includes five monophyletic tribes (nodes 7-11): Issini , Kodaianellini and Hemisphaeriini sensu (Gnezdilov 2020), Parahiraciini , and Sarimini sensu ( Wang et al. 2016 ), while the monophyly of Sarimini and Parahiraciini was not supported by Gnezdilov (2020). Figure 27. Maximum likelihood ( ML ) tree estimated from the combined based on combined sequences ( 18S , 28S , COI , Cytb ). At each node, values indicate bootstrap supports. Figure 28. Bayesian 50% consensus tree based on combined dataset. Nodes of the major clades are numbered and refer to text. Each node is documented with its posterior probability ( PP ) value. Table 4. Species used in the phylogeny analysis with accession number. "*" denotes new added sequences in this study.

Species	COI	Cytb	Gene 18S ( A2-9 R )	Gene 28S ( D3-D5 )	Gene 28S ( D6-D7 )	Collection
Agalmatium flavescens ( Olivier , 1791)	MN194180	MN191521	MN165781	MN266987	MN266956	Russia
Anatolodus musivus Dlabola , 1982	MN 194181	-	MN165782	MN266988	MN266957	Turkey
Balduza una ( Ball , 1910)	-	MN191522	MN165783	MN266989	MN266958	Mexico
Bootheca taurus ( Oshanin , 1870)	MN194182	MN191523	MN165784	MN266990	MN266959	Bulgaria
Bubastia josifovi Dlabola , 1980	-	MN191524	MN165785	MN266991	MN266960	Bulgaria
Bubastia sp.	-	MN191525	MN165786	MN266992	MN266961	Greece
Caloscelis wallengreni Stal , 1863	KX702956	KX702901	KX702855	KX761436	KX702877	China
Celyphoma quadrupla Meng & Wang , 2012	KX702919	KX702906	KX761576	KX761444	KX702806	China
Ceratogergithus pseudotessellatus ( Che , Zhang & Wang , 2007)	KX761502	KX761513	KX761491	KX761532	KX761521	China
Ceratogergithus spinosus ( Che , Zhang & Wang , 2007)	KX761502	KX761513	KX761491	KX761532	KX761521	China
Choutagus longicephalus Zhang , Wang & Che , 2006	KX761460	-	KX650620	KX761450	KX702810	China
Cixius sp.	KR343731	KX702891	JQ982514	KX761413	-	France
Clypeosmilus centrodasus Gnezdilov & Soulier-Perkins , 2017	KX761470	KX761474	KX761575	-	-	Vietnam
Conosimus coelatus Mulsant & Rey , 1855	MN194183	MN191526	MN165787	MN266993	MN266962	France
Dicranotropis hamata ( Boheman , 1847)	KX76146	-	KX702837	KX761409	-	Austria
Dictyophara europaea ( Linnaeus , 1767)	KJ911190	KX702896	KX702851	KX761427	-	Russia
Euroxenus vayssieresi ( Bonfils , Attie & Reynaud , 2001)	-	-	MN165789	MN266995	MN266964	China , Reunion
Eusudasina nantouensis Yang , 1994	HM 052838	HM452266	-	-	-	China
Euxaldar daweishanensis sp. nov.*	MK441660	MK441661	-	-	MK 441662	China
Euxaldar lenis Gnezdilov , Bourgoin & Wang , 2017	-	-	KX761565	KX761412	-	Vietnam
Falcidius limbatus (A. Costa , 1864)	MN 194185	-	MN165790	MN266996	MN266965	Italy
Flavina hainana ( Wang & Wang , 1999)	-	KX702912	KX702824	KX761453	MN381846	China
Fortunia sp.	KX761498	KX761509	KX761487	-	KX761518	China
Gergithoides carinatifrons Schumacher , 1915	KX761555	KX702905	KX761538	-	KX702805	China
Gergithoides caudospinosus Chen , Zhang & Chang , 2014*	MN171521	MW233581	-	-	MW 228374	China
Gergithoides rugulosus ( Melichar , 1906)	HM 052835	HM452279	-	-	-	China
Gergithus frontilongus Meng , Webb & Wang , 2017*	MN171522	MW233582	-	-	MW 228375	China
Gergithus parallelus Che , Zhang & Wang , 2007*	MN171523	MW233583	-	-	MW 228376	China
Gergithus yunnanensis Che , Zhang & Wang , 2007	KX702924	KX702915	KX702831	KX761456	MN381848	China
Gnezdilovius sp.*	MN 171524	-	-	-	MW 228377	China
Hemisphaerius coccinelloides ( Burmeister , 1834)	KX702934	KX702884	KX702834	KX761405	KX702861	Philippines
Hemisphaerius lysanias Fennah , 1978	KX702933	KX702883	KX702833	KX761404	KX702860	Vietnam
Hemisphaerius palaemon Fennah , 1978	KX761497	KX761508	KX761486	KX761526	KX761517	China
Hemisphaerius rufovarius Walker , 1858	KX702923	KX702913	KX702825	KX761454	KX702812	China
Hemisphaerius sp.	KX761556	KX702885	KX702835	KX761406	KX702862	Laos
Hemisphaerius testaceus Distant , 1906	HM 052831	HM452258	-	-	-	China
Hysteropterum dolichotum Gnezdilov & Mazzoni , 2004	-	-	MN165791	MN266997	MN266966	France
Issus coleoptratus ( Fabricius , 1781)	KX702932	KX761550	KX761568	KX761403	KX761560	France
Issus lauri Ahrens , 1814	-	MN191528	MN165793	MN266999	MN266968	Italy
Kervillea conspurcata ( Spinola , 1839)	MN194187	MN191529	MN165794	MN267000	MN266969	Slovenia
Kodaianella bicinctifrons Fennah , 1956	KX761458	KX702902	KX702814	KX761441	KX702802	China
Kodaianellissus intorqueus Wang , Bourgoin & Zhang , 2017	-	KX761472	KX761476	KX761480	KX761482	China
Latematium latifrons ( Fieber , 1877)	MN194188	MN191530	MN165795	MN267001	MN266970	Bulgaria
Latilica antalyica ( Dlabola , 1986)	-	MN191531	MN165796	MN267002	MN266971	Greece
Latissus dilatatus ( Fourcroy , 1785)	-	MN191532	MN165797	MN267003	MN266972	Greece
Macrodaruma pertinax Fennah , 1978	KX702931	KX702882	KX702832	KX761402	KX702859	Vietnam
Macrodaruma sp.	KX702927	KX702881	KX702828	KX761399	KX702857	China
Maculergithus multipunctatus ( Che , Zhang & Wang , 2007)	KX702918	KX702904	KX702816	KX761443	KX702804	China
Maculergithus nonomaculatus ( Meng & Wang , 2012)	KX761503	KX761514	KX761492	KX761533	KX761522	China
Mongoliana serrata Che , Wang & Chou , 2003	HM 052830	HM452272	-	-	-	China
Mongoliana sinuata Che , Wang & Chou , 2003	KX761459	KX702908	KX702820	KX761448	-	China
Mongoliana sp. 2	-	-	KX761566	KX761534	MN381849	China
Mongoliana sp.1	-	MN332233	MN422135	MN381854	-	Thailand
Mongoliana triangularis Che , Wang & Chou , 2003	-	KX761510	KX761561	KX761528	-	China
Mulsantereum maculifrons ( Mulsant & Rey , 1855)	KX702928	KX761551	KX761569	KX761400	MN381847	France
Mycterodus drosopoulosi Dlabola , 1982	MN194189	MN191533	MN165798	MN267004	MN266973	Greece
Mycterodus goricus ( Dlabola , 1958)	MN194190	MN191534	MN165799	MN267005	MN266974	Greece
Neodurium hamatum Wang & Wang , 2011	KX702920	-	KX702818	KX761446	MN381844	China
Neogergithoides tubercularis Sun , Meng & Wang , 2012	KX761558	KX702910	KX702822	KX761451	MN381845	China
Ophthalmosphaerius trilobulus ( Che , Zhang & Wang , 2006)	KX761462	KX702914	KX702826	KX761455	KX702813	China
Palmallorcus punctulatus ( Rambur , 1840)	KX761462	KX702914	MN165800	MN267006	MN266975	Greece
Proteinissus bilimeki Fowler , 1904	MN194193	MN191537	MN165803	MN267009	MN266978	Greece
Retaldar yanitubus sp. nov.	MN381857	MN332232	MN381856	MN381853	MN381851	China
Rhombissus sp.	-	MN332231	MN381855	MN381852	MN381850	China
Sarima bifurca Meng & Wang , 2016	KX702921	KX761552	KX702819	KX761447	KX702808	China
Scorlupaster heptapotamicum Mitjaev , 1971	-	-	-	MN267010	MN266979	Kazakhstan
Scorlupella discolor ( Germar , 1821)	-	-	MN165804	MN267011	MN266980	Bulgaria
Tetrica sp.	KX702922	KX702909	KX702821	KX761449	KX702809	China
Thalassana ephialtes ( Linnavuori , 1971)	MN194194	MN191538	MN165805	MN267012	MN266981	Turkey
Tingissus guadarramense ( Melichar , 1906)	KX702935	KX702886	MN165806	MN267013	MN266982	Portugal
Traxus fulvus Metcalf , 1923	MN194195	MN191539	MN165807	MN267014	MN266983	Mexico
Trypetimorpha occidentalis Huang & Bourgoin , 1993	KX702957	-	KX761546	KX761437	-	Kazakhstan
Tshurtshurnella bicolorata Gnezdilov & Oezgen , 2018	MN194196	MN191540	MN165808	MN267015	MN266984	Turkey
Tshurtshurnella zelleri ( Kirschbaum , 1868)	-	MN191541	MN165809	MN267016	MN266985	Italy
Zopherisca penelopae ( Dlabola , 1974)	-	-	MN165810	MN267017	MN266986	Greece