Cheiloneurus, Westwood

Noyes, John Stuart, 2023, ENCYRTIDAE OF COSTA RICA (HYMENOPTERA: CHALCIDOIDEA), 4 Subfamily Encyrtinae: tribes Arrhenophagini, Habrolepidini, Cerapterocerini, Cheiloneurini, Trechnitini, Cercobelini, Polaszekiini, Protyndarichoidini, Gahaniellini and Syrphophagini (part), mainly primary parasitoids and hyperparasitoids of Coccoidea and Psylloidea (Hemiptera), Taxonomic Monographs on Neotropical Hymenoptera (Oxford, England) 2 (11), pp. 1-921 : 197-200

Genus CHEILONEURUS Westwood

Cheiloneurus Westwood, 1833a:343 . Type species: Encyrtus elegans Dalman , by monotypy.

Chilonevrus Agassiz, 1848 . Unjustified emendation of Cheiloneurus Westwood.

Chrysopophagus Ashmead, 1894:246 . Type species: Chrysopophagus compressicornis Ashmead , by monotypy. Synonymy with Cheiloneurus by Trjapitzin & Gordh (1978a:365).

Cheloneurus; Förster, 1956:50. Misspelling of Cheiloneurus .

Chiloneurus ; Förster, 1856:50. Misspelling of Cheiloneurus .

Zaomma Ashmead, 1900:401 . Type species: Encyrtus argentipes Howard , by original designation and monotypy. syn.nov.

Blatticida Ashmead, 1904:305 . Type species: Blatticida pulchra Ashmead , by monotypy. Synonymy with Cheiloneurus by Trjapitzin & Gordh (1978 b:636).

Apterencyrtus Ashmead, 1905:5 . Type species: Apterencyrtus pulchricornis Ashmead , by original designation and monotypy. Synonymy with Zaomma by Gordh & Trjapitzin (1979:34). syn.nov.

Echthrogonatopus Perkins, 1906:256 . Type species: Echthrogonatopus exitiosus Perkins , by designation of Gahan & Fagan (1923:48). Synonymy with Cheiloneurus by Guerrieri & Viggiani (2005:306).

Saronotum Perkins, 1906:269-260 . Type species: Saronotum australiae Perkins , by original designation. Synonymy with Cheiloneurus by Noyes & Hayat (1984:249).

Cristatithorax Girault, 1911:169 . Type species: Cristatithorax pulcher Girault , by original designation. Synonymy with Cheiloneurus by Mercet (1921:637).

Eusemionella Girault, 1915a:78 . Type species: Eusemionella cristata Girault , by original designation. Synonymy with Cheiloneurus by Noyes & Hayat (1984:249).

Chrysopophagoides Girault, 1915a:90 . Type species: Chrysopophagoides westwoodi Girault , by original designation. Synonymy with Cheiloneurus by Noyes & Hayat (1984:249).

Paracheiloneurus Girault : 1915a:119. Type species: Cheiloneurus perpulcher Girault , by original designation; subgenus of Cheiloneurus . Synonymy with Cheiloneurus by Noyes & Hayat (1984:249).

Epicheiloneurus Girault, 1915a:173 . Type species: Epicheiloneurus albicoxa Girault , by original designation. Synonymy with Cheiloneurus by Noyes & Hayat (1984:249).

Metallonoidea Girault, 1915a:170-171 . Type species: Metallonoidea brittanica Girault , by monotypy. Synonymy with Zaomma by Gordh & Trjapitzin (1979:34). syn.nov.

Eusemionopsis Girault, 1918:3 . Type species: Eusemionopsis centaurus Girault , by original designation. Synonymy with Cheiloneurus by Noyes & Hayat (1984:249).

Hypergonatopus Timberlake, 1922:142 . Type species: Echthrogonatopus hawaiiensis Perkins , by original designation. Synonymy with Cheiloneurus by Guerrieri & Viggiani (2005:306).

Procheiloneurus Girault, 1920a:39 . Type species: Procheiloneurus triguttatipennis Girault , by original designation. Synonymy with Cheiloneurus by Dahms & Gordh (1997:113 - 114,115-116).

Chiloneurinus Mercet, 1921:646 . Type species: Chiloneurus microphagus Mayr , by original designation and monotypy. Synonymy with Zaomma by Trjapitzin (1978:310). syn.nov.

Aulonops Timberlake, 1922:158-159 . Type species: Aulonops bifasciata Timberlake , by original designation. Synonymy with Cheiloneurus by Guerrieri (2006:2396).

Raphaelana Girault, 1926:66 . Replacement name for Procheiloneurus Girault, 1920 nec Prochiloneurus Silvestri, 1915 .

Bekilyia Risbec, 1952:40 . Type species: Bekilyia metallica Risbec , by monotypy. Synonymy with Cheiloneurus by Noyes & Prinsloo (1998:78,84).

Metacheiloneurus Hoffer, 1957b:336 . Type species: Metacheiloneurus moestus Hoffer , by monotypy. Synonymy with Cheiloneurus by Hoffer (1959:33).

Lepidoneurus Hoffer, 1957:340 b. Type species: Chiloneurus kollari Mayr , by original designation (as subgenus of Cheiloneurus Westwood ). Synonymy with Cheiloneurus by Trjapitzin (1989:305).

Richardsius Alam, 1957:439 . Type species: Apterencyrtus thomsoniscae Alam , by original designation (as subgenus of Apterencyrtus Ashmead ). Synonymy with Zaomma by Trjapitzin (1989:312). syn.nov.

Tobiasia Trjapitzin, 1962:567 . Type species: Tobiasia bifasciata Trjapitzin , by monotypy. Synonymy with Cheiloneurus by Trjapitzin & Triapitsyn (2008:465).

Metapterencyrtus Tachikawa, 1963b:213-214 . Type species: Metapterencyrtus eriococci Tachikawa , by original designation. Synonymy with Zaomma by Gordh & Trjapitzin (1979:34). syn.nov.

Cheilonorus ; OILB, 1971:20. Misspelling of Cheiloneurus .

Cheilioneurus; Noyes, 2010:94. Misspelling of Cheiloneurus .

Female. Overall length about 0.8-4.5mm.

Body varying from completely yellow or orange to dark brown and largely metallic green; mesoscutum often posteriorly with a strong metallic dark band clothed with dense silvery setae, sometimes only silvery setae; legs varying from completely yellow or pale orange to mostly dark brown; fore wing rarely completely hyaline, usually distinctly infuscate.

Head with with an oval, shiny bottomed depression adjacent to eye margin between posterior ocellus and occipital margin; malar sulcus absent or very weak, indicated by a slight change in sculpture; antenna with pedicel and flagellum subcylindrical, segments becoming broader distally, clava at least as broad as F1, with apex rounded or with a slight to strong, oblique apical truncation; mandible basically tridentate, varying from 3 very sharp teeth acute teeth, upper tooth sometimes very short, lower teeth sometimes very long; through to 3 subequal, relatively short teeth to 1 tooth and a broad truncation; palp formula 4-3.

Mesoscutum without notaular lines, mostly with imbricate-reticulate or polygonally reticulate sculpture, cells rarely uniform, mostly at least some anterior cells longitudinally elongate, sometimes all sculpture longitudinally elongate striate-reticulate to striate and slightly diverging posteriorly; scutellum with similar or distinctly deeper polygonally reticulate sculpture, sometimes arranged in whorls; scutellum almost always with a subapical tuft composed of tightly packed, scale-like setae that are scattered and not arranged in distinct straight lines; fore wing fully developed or strongly reduced, sometimes hardly reaching gaster; fully developed fore wing about 2.2-3.3X as long as broad, reduced fore wing up to 3.9X as long as broad; fully developed fore wing mostly infuscate with a naked, hyaline streak connecting apex of postmarginal and stigmal veins; submarginal vein with parastigma at least slightly broadened and frequently downcurved, sometimes strongly; marginal vein long, at least 3X as long as broad, at least 1.5X as long as the stigmal vein and rarely less than 3X as long as the postmarginal vein (in some species with completely hyaline wings the postmarginal vein is as long the stigmal vein and about 0.5X as long as the marginal vein); filum spinosum present.

Gaster sometimes with a pair of gland-like structures on TI and TV; hypopygium not reaching apex of gaster; ovipositor hidden to very strongly exserted; gonostylus free.

Male. Length about 0.6-1.8mm.

Body usually dark brown with a slight metallic sheen, rarely completely or partially yellow; fore wing hyaline, extremely rarely infuscate as in female; antenna with 6 funicle segments, all longer than broad and clothed with whorls of long setae, the longest of which may be up to 8X as long as diameter of segments; clava entire and usually slightly shorter than F5 and F6 combined; sculpture of mesoscutum and scutellum usually similar to that of female; subapical tuft on scutellum very rarely present; fore wing with venation similar to that of female but marginal vein usually relatively shorter; phallobase with parameres short, digiti each about 2-3X as long as broad and with a single apical tooth; aedeagus mostly about half as long as mid tibia, about 10- 16X as long as broad but very slightly broadened subapically with apex rounded.

DISTRIBUTION. Cosmopolitan.

HOSTS. Mainly secondary parasitoids of scale insects via other encyrtid primary parasitoids or leaf hoppers via other parasitoids. Some species are recorded as primary parasitoids of predators associated with aphids or other sternorrhynchous hemipterans. Cheiloneurus aliphera sp.nov. is recorded below from cricket eggs in Colombia, and Cheiloneurus leptulus Annecke & Prinsloo is recorded as a parasitoid of the larvae of Ceratina Latreille ( Hymenoptera : Apidae ) in Tanzania ( Annecke & Prinsloo, 1977). One species appears to be a gregarious, facultative hyperparasitoid of moth prepupae or pupae ( Lepidoptera ) via braconid primary parasitoids ( Manickavasagam et al., 2008).

COMMENTS. Zaomma has long been treated as a distinct genus from Cheiloneurus although the included species have very similar biologies and morphology. With a few exceptions, both genera include species that are secondary parasitoids of Coccoidea (Hemiptera) , although species of Zaomma specialise as secondary parasitoids of smaller scales ( Diaspididae ) whilst species of Cheiloneurus are associated with larger scales ( Coccidae , etc.). In general, individuals of Zaomma are smaller than those of Cheiloneurus and have hyaline fore wings and the scutellum has a weak subapical tuft whilst those of Cheiloneurus have infuscate fore wings and the scutellum usually has a distinct subapical tuft. This separation was supported when Prinsloo (1979b) showed that all Afrotropical species of Zaomma have paired “gland-like” structures on TI and TV of the gaster which he also found in the common European species, Zaomma lambinus . The current work has shown that these structures are also present in Zaomma argentipes ( Fig. 522), the type species of the genus. No species currently placed in Cheiloneurus is known to possess these structures. However, in at least two species described as new here ( dalycera and idris ), these gland--like structures are absent, but appear to be indicated by somewhat irregular changes in sculpture. In general respects these species are very similar to argentipes . Another species described here as new ( magnolia ; Fig. 504) possesses distinct gland-like structures on TI and TV of the gaster yet has strongly infuscate fore wings ( Fig. 499). I therefore think that treating Zaomma as a separate genus from Cheiloneurus is untenable and formally propose the synonymy of the two genera (syn. nov.). As a result of this synonymy the following new combinations in Cheiloneurus are proposed: abas (Trjapitzin) (from Apterencyrtus ); acaciae (Risbec) (from Paralitomastix ); acanthococci (Pilipyuk & Trjapitzin) (from Apterencyrtus ); argentipes (Howard) (from Encyrtus ); astera (Hayat) (from Zaomma ); carinae (Prinsloo) (from Zaomma ); cestus (Prinsloo) (from Zaomma ); danzigae (Pilipyuk & Trjapitzin) (from Apterencyrtus ); epytus (Walker) (from Encyrtus ); eriococci (Ferrière) (from Apterencyrtus ); ficusae (Risbec) (from Adelencyrtus ); hirsutus (Ratzeburg) (from Encyrtus ); lambinus (Walker) (from Encyrtus ); sitis (Prinsloo) (from Zaomma ); vix (Prinsloo) (from Zaomma ); xhosa (Prinsloo) (from Zaomma ) (all comb.nov.).

One group of species (related to hamadryas sp.nov., see key couplets 17 to 31) appears to form a monophyletic group which might be considered to be out of place within Cheiloneurus and deserve separate generic status. The species are characterised by having the mandible with two elongate, sharp, lower teeth and a short or vestigial upper, third tooth (e.g. Figs 610, 617. 620, 638, 644, 669) and a hyaline, or weakly infuscate, fore wing without any indication of a hyaline, naked streak connecting the apices of the postmarginal and stigmal veins (e.g. Figs 604, 608, 613, 670, 677). At present I prefer to include these species within Cheiloneurus because all other characters agree with the current definition of the genus.

There is no doubt that Cheiloneurus , as understood here, is morphologically an extremely variable genus and probably requires a reassessment of its generic limits. Unfortunately, this is beyond the scope of the current work. This would be an enormous task that would require a holistic approach based on a detailed examination of material from all parts of the world that includes representatives of all genus group names that are currently treated as invalid synonyms.

See comments under Prochiloneurus (p. 459) and Ludesia (p. 179).

IDENTIFICATION. A very diverse genus with 272 described species worldwide, including 102 described below as new. Identification of species can be difficult with very few revisions or detailed studies available: Gordh & Trjapitzin , 1979 (key to 7 species of Zaomma ); Guerrieri & Viggiani, 2005 (revision of 14 species of Cheiloneurus associated with Hymenoptera , Dryinidae ); Gahan, 1914 (key to 8 North American species of Cheiloneurus ); Trjapitzin & Triapitsyn, 2008 (new species of Cheiloneurus from USA, Mexico and Cuba , key to 12 species of Cheiloneurus without a scutellar tuft, key to 14 species of elegans group); Trjapitzin, 1971 (key to 13 Palaearctic species of Cheiloneurus ); Trjapitzin, 1989 (key to 21 Palaearctic species of Cheiloneurus and 6 species of Zaomma ); Compere, 1938 (key to 7 Afrotropical species of Cheiloneurus ); Prinsloo, 1979b (revision of 5 Afrotropical species of Zaomma ); Hayat, 2006 (key to 33 Indian species of Cheiloneurus ); Shi et al., 1994 (key to 10 Chinese species of Cheiloneurus ).