Gonatocerus Nees ab Esenbeck 1834

Genus Gonatocerus Nees ab Esenbeck, 1834

Gonatocerus Nees ab Esenbeck 1834: 192 –193.

Type species: Gonatocerus longicornis Nees ab Esenbeck, by monotypy. Subsequent taxonomic references: Foerster 1847: 209 –210 (diagnosis); Foerster 1856: 116 –118 (key, discussion); Dalla Torre 1898: 429 –430 (catalog); Girault 1911: 273 –277 (North American species); Kryger 1934: 503 –505 (nomenclatural remarks); Nikol’skaya 1952: 538 (key); Bouček & Graham 1972: 125 –130 (genus and type species identity); Hellén 1974: 8 –9 (diagnosis, key to Finnish species); Sahad 1982c: 198 (key to Japanese species); Sahad & Hirashima 1984: 7 –8 (historical review), 11–13 (diagnosis and key to species of Japan and adjacent regions); Schauff 1984: 36 –37 (genus definition); Matthews 1986: 214, 216 (key to species groups and British species); Huber 1986: 220 –222 (historical review, host records, etc.); Huber 1988: 5 –7, 23–24, 29–30 (historical review, species groups and Nearctic species of two groups); Noyes & Valentine 1989: 34 –35 (diagnosis and remarks on New Zealand species); Yoshimoto 1990: 36 –42 (species groups and list of Western Hemisphere species); Zeya & Hayat 1995: 52 –59 (redescription, relationships, and key to species groups); Huber & Beardsley 2000: 51 –53 (species in the Hawaiian Islands); Triapitsyn & Huber 2000: 614 (key to species groups in the Palaearctic region); Baquero & Jordana 2003: 3 – 5 (diagnosis, key to species groups and species in Navarre, Spain); Viggiani 2005: 65 (comments on male genitalia); Donev 2005: 376 –377 (key to species groups in the Balkan Peninsula); Lin et al. 2007: 34 –37 (short diagnosis, list of Australian species); Huber et al. 2009: 272 (key), 278 (key), 288, 291 (brief diagnosis, comments); Triapitsyn et al. 2010: 10–13 (synonymy, diagnosis, summary on the former species groups, identification key to subgenera); Guo et al. 2011: 53 –54 (short overview); Triapitsyn & Proshchalykin 2012: 207 –208 (catalog).

Lymaenon Walker 1846: 49 –50.

Type species: Lymaenon acuminatus Walker, by subsequent designation by Gahan & Fagan 1923: 82. Synonymized under Gonatocerus by Foerster 1856: 118 and listed as its synonym by Bouček & Graham 1972: 126; treated as a subgenus of Gonatocerus by Herting 1972: 14 and Triapitsyn et al. 2010: 41–42, and as a valid genus by Kryger 1934: 503 –505, Debauche 1948: 78 –86 (references, diagnosis, historical review, discussion, species groups, and keys to Belgian species), Debauche 1949: 4 –5 (discussion on nomenclature), 25–30 (diagnosis, species groups, and key to the species in the Ethiopian region); Kryger 1950: 68 –71 (historical review); Ison 1958: 68 (diagnosis); Annecke & Doutt 1961: 4 (key), 13 (diagnosis, distribution, subgenera), and Viggiani 1969: 37 –38 (discussion). Other important taxonomic references: Mathot 1969: 9 –12 (key to Belgian species); Viggiani 1973: 279 (male genitalia); Trjapitzin 1978: 524 –527 (key to European species); Viggiani 1988: 560 (host associations, diagnosis); Viggiani & Jesu 1988: 1022 –1023 (host associations, records from Italy).

Rachistus Foerster 1847: 203.

Type species: Ooctonus litoralis Haliday, by subsequent designation by Gahan & Fagan 1923: 128. Synonymized under Gonatocerus by Foerster 1856: 119 (and listed as its synonym by Bouček & Graham 1972: 127), under Lymaenon by Debauche 1949: 25, and under G. (Lymaenon) by Triapitsyn et al. 2010: 41.

Rhachistus Dalla Torre 1898: 429 (catalog). Unjustified emendation of Rachistus Foerster.

Cosmocomoidea Howard 1908: 68.

Type species: Cosmocomoidea morrilli Howard, by monotypy. Treated as a synonym of Ooctonus Haliday by Girault 1929: 20, as a subgenus under Lymaenon by Ogloblin 1959: 50 –56 and Annecke & Doutt 1961: 4, and synonymized under Gonatocerus by Bouček & Graham 1972: 127; recognized as a subgenus of Gonatocerus by Triapitsyn et al. 2010: 94–95.

Oophilus Enock 1909: 458.

Type species: Oophilus longicauda Enock, by monotypy. Synonymized under Gonatocerus by Girault 1911: 276 –277 (and listed as its synonym by Bouček & Graham 1972: 127), under Lymaenon by Debauche 1949: 25, and under G. (Lymaenon) by Triapitsyn et al. 2010: 41. Treated as a separate genus by Kryger 1950: 79 –81.

Agonatocerus Girault 1913a: 276.

Type species: Agonatocerus humboldti Girault, by original designation. Synonymized under Gonatocerus by Girault 1915: 156 (and listed as its synonym by Bouček & Graham 1972: 127), under Lymaenon by Debauche 1949: 25, and under G. (Lymaenon) by Triapitsyn et al. 2010: 41.

Gonatoceroides Girault 1913b: 255 (as subgenus of Gonatocerus).

Type species: Gonatocerus (Gonatoceroides) australicus Girault [as australica], by original designation. Synonymized under Gonatocerus by Girault 1915: 156 (and listed as its synonym by Bouček & Graham 1972: 127), under Lymaenon by Debauche 1949: 25, and under G. (Lymaenon) by Triapitsyn et al. 2010: 41.

Gastrogonatocerus Ogloblin 1935: 65 (as subgenus of Gonatocerus).

Type species: Gonatocerus (Gastrogonatocerus) membraciphagus Ogloblin, by original designation. Treated as a subgenus of Lymaenon by Ogloblin 1938: 93 –106 (in part) and Annecke & Doutt 1961: 4, and synonymized under Lymaenon by Debauche 1949: 25 and under Gonatocerus by Bouček & Graham 1972: 127; formally reinstated as a subgenus of Gonatocerus by Triapitsyn et al. 2010: 11, 57.

Gahanopsis Ogloblin 1946: 286, 288 (as subgenus of Lymaenon).

Type species: Lymaenon (Gahanopsis) deficiens Ogloblin, by original designation. Treated as a valid genus by Annecke & Doutt 1961: 4, 13, Huber 1986: 220, and Luft Albarracin et al. 2009: 8, 13; as deficiens species group (without a formal synonymy under Gonatocerus) by Huber 1988: 23 –24 and Yoshimoto 1990: 37, 41; synonymized under Gonatocerus and treated as its subgenus by Triapitsyn et al. 2010: 11, 80.

Decarthrius Debauche 1949: 21 –22.

Type species: Decarthrius straeleni Debauche, by original designation. Synonymy under Gahanopsis by Annecke & Doutt 1961: 13; synonymized under Gonatocerus and G. (Lymaenon) by Triapitsyn et al. 2010: 11, 41.

Diagnosis. See Triapitsyn et al. (2010). The following combination of features will separate all Palaearctic Gonatocerus from Ooctonus, the only other genus in the region with 5-segmented tarsi whose female also has antenna with 8 funicle segments. Both sexes: face with subantennal sulci (Figs 50, 116, 180, 318); marginal vein with two macrochaetae and the hypochaeta about midway between them. Female: gastral segment 1 similar in length to segment 2. Male: genitalia not encapsulated in a tubular capsule or phallobase; instead, aedeagus attached directly to the apical sternum, with two long apodemes united distally (V-shaped) and a long median apodeme.

Classification. Gonatocerus is a relatively easily recognized genus, so any generic key to the Mymaridae may be used for its recognition in the Palaearctic region: Annecke & Doutt (1961) for the world genera, Schauff (1984) for the Holarctic genera, and Triapitsyn & Huber (2000) for the Palaearctic genera.

Triapitsyn et al. (2010) commented on the place of Gonatocerus within the higher classification of Mymaridae and its relationships with other genera and rediagnosed the genus and its subgenera and species groups of G. (Cosmocomoidea). The latter subgenus as well as G. (Lymaenon Walker) and G. (Gonatocerus Nees ab Esenbeck) occur in the Palaearctic region whereas G. (Gahanopsis Ogloblin) and G. (Gastrogonatocerus Ogloblin) are native to the New World and occur mainly in the Neotropics. The latter two subgenera seem to be derived offshoots of G. (Lymaenon) and G. (Gonatocerus), respectively, that parasitize mainly eggs of Membracidae (Hemiptera).

Distribution. Cosmopolitan.

Hosts. See Sahad & Hirashima (1984), Huber (1986, 1988), Zeya & Hayat (1995), and Triapitsyn et al. (2010) for lists by genus or under each species treated by them. In the Palaearctic region, reliable host records of Gonatocerus spp. are from eggs of Cicadellidae and Membracidae (Hemiptera: Membracoidea). Miridae (Hemiptera) is a new host family record presented here (see under G. fuscicornis). Other, non-membracoid, host records need confirmation.

Key to subgenera of Gonatocerus in the Palaearctic region (both sexes)

1 Pronotum with lateral lobes widely separated by lightly sclerotized median area (as in Figs 53, 146); dorsellum strap-shaped (as in Figs 52, 147)................................................................... G. (Lymaenon Walker)

– Pronotum with lateral lobes abutting medially (as in Figs 14, 23, 266, 319); dorsellum rhomboidal or triangular (as in Figs 13, 22, 44, 219, 228, 255, 259, 320).......................................................................... 2

2(1) Fore wing without a large bare area (more or less evenly setose) behind marginal vein (as in Figs 6, 24, 30, 35).................................................................................... G. (Gonatocerus Nees ab Esenbeck)

– Fore wing with a large bare area behind marginal vein: setae either absent, or just a few present, behind entire length of marginal vein (as in Figs 220, 260, 296) or at least mostly absent behind base of marginal vein (Fig. 321)................................................................................................ G. (Cosmocomoidea Howard)