Gonatocerus deleoni S. Triapitsyn, Logarzo & Virla, 2008

Triapitsyn, Serguei V., Logarzo, Guillermo A., De León, Jesse H. & Virla, Eduardo G., 2008, A new Gonatocerus (Hymenoptera: Mymaridae) from Argentina, with taxonomic notes and molecular data on the G. tuberculifemur species complex, Zootaxa 1949 (1), pp. 1-29 : 6-10

Gonatocerus deleoni S. Triapitsyn, Logarzo & Virla , sp. n.

( Figs 1–9 )

Gonatocerus tuberculifemur (Ogloblin) “Clade 2”: de León, Logarzo et al. 2006a: 40–42; de León, Logarzo et al. 2006b: 44–46; de León et al. 2007: 73–75; de León, Logarzo et al. 2008: 97–106.

Type material. Holotype female on slide [ MLPA]: ARGENTINA: Buenos Aires, Hurlingham, F1 [i.e., first generation] progeny reared on eggs of Tapajosa rubromarginata (Signoret) at USDA, ARS SABCL, emerged 22.iii.2006 (collection code SRc2); originally from: Mendoza, San Rafael, G. Logarzo, E. Virla, ex. T. rubromarginata sentinel eggs on citrus exposed 27–31.i.2006. Paratypes: ARGENTINA. Buenos Aires, Hurlingham, F1 progeny reared on eggs of Tapajosa rubromarginata (Signoret) at USDA, ARS SABCL (originally from: Mendoza, San Rafael, G. Logarzo, E. Virla, ex. T. rubromarginata sentinel eggs exposed 27–31.i.2006): emerged 8.iii.2006 [1 female on point, UCRC]; emerged 22.iii.2006 [1 male on point, UCRC, and 2 males on slides, MLPA, UCRC]; emerged 23–25.iii.2006 [1 female on slide, UCRC, 3 females on points, CNCI, UCRC, USNM, and 9 males on points: CNCI (1), IMLA (2), MLPA (2), UCRC (3), USNM (1)]; emerged 25.iii.2006 [2 females on points, IMLA, UCRC]; emerged 3.iv.2006 [1 female on point, UCRC]; emerged 4.iv.2006 [1 female on point, UCRC]. Mendoza, San Rafael, G. Logarzo, E. Virla, 10.ii.2006, 13.ii.2006, and 15.ii.2006, ex. eggs of T. rubromarginata on lemon (field host range study) [1 female on slide and 3 females on points, UCRC].

Additional material examined (all in alcohol, USDA, ARS SABCL)

ARGENTINA: Mendoza, San Rafael, 34°30’36.3’’S 68°22’57.6’’W, 714 m, emerged 24–30.i.2004 from sentinel eggs of T. rubromarginata on citrus exposed 10–18.i.2004, G. Logarzo, L. Varone [32 females, 6 males]. Originally from: Mendoza, General Alvear, 34°58’35.1’’S 67°40’21.3’’W, 506 m, emerged 1–3.ii.2007 from T. rubromarginata sentinel eggs exposed 19–23.i.2007, G. Logarzo, F. Palottini; F1 progeny reared on T. rubromarginata eggs at USDA, ARS SABCL in Hurlingham, Buenos Aires, exposed 1–3.ii.2007, emerged 11–15.ii.2007 [3 females, 2 males]. Originally from: Mendoza, Rama Caída, 34°41’20.0’’S 68°21’27.6’’W, 681 m, emerged 1.ii.2007 from T. rubromarginata sentinel eggs exposed 21–23.i.2007, G. Logarzo, F. Palottini; F1 progeny reared on eggs of T. rubromarginata at USDA, ARS SABCL, exposed 1–3.ii.2007, emerged 15–16.ii.2007 [2 males]. Originally from: Mendoza, San Rafael, emerged 1–3.ii.2007 from T. rubromarginata sentinel eggs exposed 19–23.i.2007, G. Logarzo, F. Palottini; F1 progeny reared on eggs of T. rubromarginata at USDA, ARS SABCL, exposed 7–9.ii.2007, emerged 16–21.ii.2007 [7 females, 1 male].

Description. FEMALE (holotype and paratypes). Body length 0.9–1.1 mm. Head and mesosoma ( Fig. 3 ) dark brown, gaster brown to dark brown (basal terga a little lighter than apical ones); appendages light brown to brown.

Antenna ( Fig. 1 ) with radicle 2.1–2.2 x as long as wide, rest of scape 2.8–3.0 x as long as wide, with strong setae; pedicel longer than F1; all funicular segments longer than wide and densely setose (setae short); F2 longer than F1 and shorter than F3 (usually the longest funicular segment, particularly when a longitudinal sensillum is present), F4 and F5 subequal in length, F6 as long as F7 and each a little shorter than F5; F8 shorter than F7; F1 and F2 without longitudinal sensilla, longitudinal sensilla on F3 (0 or 1), F4 (1), F5 (2), F6 (2), F7 (2), and F8 (2); clava with 8 longitudinal sensilla, 3.6–3.7 x as long as wide, its ventral surface covered with numerous minute, short setae and placoid sensilla, its dorsal surface densely covered with longer setae.

Pronotum divided medially, each lobe with 2 strong dorsal and 2 weak lateral setae. Mesoscutum much wider than long, shorter than scutellum; midlobe of mesoscutum with a pair of strong setae. Dorsellum of metanotum with posterior margin widely angulate medially. Propodeum ( Fig. 2 ) with lateral carinae and slightly curved submedian carinae (not meeting near anterior and meeting at posterior margins of propodeum, almost extending to its anterior margin); the propodeum smooth between submedian carinae but elsewhere with a faint cellulate sculpture (as in Fig. 9 ). Protibia without conical sensilla.

Forewing ( Fig. 4 ) 3.4–3.5 x as long as wide; marginal setae short, the longest marginal seta 1/5–1/4 greatest wing width. Forewing disc slightly infuscate throughout, with a distinct darker spot behind stigmal vein, bare behind submarginal and marginal veins except for a few setae at apex of marginal vein, remainder of the disc densely setose. Submarginal vein with 1 macrochaeta and 2 smaller setae, marginal vein with 4 setae between proximal and distal macrochaetae. Hind wing 17–18 x as long as wide, the disc slightly infumate and mostly bare except for the usual two complete rows of setae along margins and several scattered setae at apex and behind apex of venation.

Gaster a little longer than mesosoma. Petiole about 1.6 x as wide as long, subtrapezoidal. Ovipositor about 7/10 length of gaster, not exserted beyond its apex. Ovipositor length: mesotibia length ratio about 0.9. Outer plates of ovipositor each with 1 distal seta.

Measurements of the holotype (in µm, as length or length:width). Mesosoma 535; petiole 43; gaster 548; ovipositor 373. Antenna: radicle 52; rest of scape 158; pedicel 70; F1 48; F2 66; F3 85; F4 72; F5 72; F6 67; F7 67; F8 60; clava 206. Forewing 1285:375; longest marginal seta 91. Hind wing 953:57; longest marginal seta 124.

MALE (paratypes). Body length 0.9–1.1 mm. Similar to female in coloration. Antenna ( Fig. 5 ) with scape and radicle fused, scape (excluding radicle) 2.9–3.0 x as long as wide; pedicel very small, all flagellomeres much longer than wide and with numerous longitudinal sensilla. Propodeum with submedian carinae not extending to its anterior margin ( Figs 6 , 9 ). Forewing ( Fig. 8 ) 3.4–3.5 x as long as wide. Apex of apodeme of genital sternite more or less acute ( Fig. 7 ).

Diagnosis. Member of the ater species group of Gonatocerus as defined by Huber (1988); its subgroup placement, however, is unclear: morphologically, it fits better the ater subgroup but molecularly, it clusters with the morrilli subgroup species based on both COI and ITS2 sequence data ( de León, Logarzo et al. 2008). The following morphological features of the male distinguish this new species from G. tuberculifemur (i.e., “Clade X” from the type locality in Pucará) and G. sp. near tuberculifemur “Clade 1”: submedian carinae on the propodeum ( Figs 6 , 9 ) relatively less prominent anteriorly, not extending to the anterior margin of the propodeum [almost extending to the anterior margin of the propodeum in G. sp. near tuberculifemur “Clade 1” ( Fig. 10 ) and also in G. tuberculifemur from Pucará]; apex of the apodeme of the genital sternite ( Fig. 7 ) more or less acute [blunt in G. sp. near tuberculifemur “Clade 1” ( Fig. 16 ) and in G. tuberculifemur from Pucará]. Gonatocerus deleoni does not match the descriptions and available types of any of the numerous species of Gonatocerus from Argentina and elsewhere in South America described by A.A. Ogloblin and others [the first author examined all of them except for one lost type of an unrelated species (from another species group) from Ecuador for a forthcoming revision of the described Neotropical species of Gonatocerus ( Triapitsyn 2006b, 2007)].

Etymology. This species is named in honor of our colleague and friend (and co-author of this communication) Jesse H. de León, who first identified it as a separate entity from G. tuberculifemur and G. sp. near tuberculifemur “Clade 1” using molecular methods.

Natural hosts. Unknown? Proconiini (Cicadellidae) .

Factitious hosts. Tapajosa rubromarginata (Signoret) (from sentinel eggs of which this species was reared in Argentina) and also Homalodisca vitripennis (Germar) in the USA (both Proconiini ). Adult females and males of G. deleoni sp. n. were sent by G.A. Logarzo under a permit from Buenos Aires, Argentina on 7.iii.2007 to the University of California, Riverside (UCR), California, USA quarantine facility, where a colony was then originated by S.V. Triapitsyn and V.V. Berezovskiy on eggs of a factitious host, H. vitripennis , in Euonymus japonica leaves. This material originated from the cross of the females (F1 progeny, reared at USDA, ARS SABCL on T. rubromarginata eggs, G. Logarzo, exposed 1–3.ii.2007, emerged 13–19.ii.2007; originally from the sentinel eggs of T. rubromarginata collected in San Rafael, Mendoza, exposed 19–23.i.2007, G. Logarzo, F. Palottini) and the males (F1 progeny of the cross between a male from the abovementioned collection in San Rafael and a female collected in Rama Caída, Mendoza, exposed 19–23.i.2007, G. Logarzo, F. Palottini), and then reared (in the second generation) on eggs of T. rubromarginata at USDA, ARS SABCL (exposed 16–19.ii.2007, emerged 28.ii–1.iii.2007). Upon arrival to UCR quarantine, the colony originating females were exposed to H. vitripennis eggs on 9.iii.2007, and the next generation (progeny of both sexes) wasps emerged 28–20.iii.2007. Of the colony originators, we preserved as vouchers and slidemounted 1 female and 1 male specimens [UCRC] (19.iii.2007, V. Berezovskiy); also preserved (4.v.2007, V. Berezovskiy) as vouchers and slide-mounted were 1 female and 1 male specimens [UCRC] of the second generation progeny from the established UCR quarantine colony on H. vitripennis eggs. These four specimens are not included in the type series of G. deleoni sp. n.

Biology. Our field host range studies revealed that G. deleoni sp. n. parasitizes only eggs of T. rubromarginata and it would not attack eggs of Cicadellini (Logarzo unpublished data). This biological trait, combined with the limited natural range of G. deleoni sp. n. that is confined to a few desert oases in Mendoza Province, Argentina, make this species potentially a more suitable and promising candidate agent for the neoclassical biological control against H. vitripennis in California than G. sp. near tuberculifemur “Clade 1”. Otherwise, its biology is similar to that of G. sp. near tuberculifemur “Clade 1”, which is well known ( Virla et al. 2005). Another important factor that may make G. deleoni sp. n. a promising biological control candidate is the unique climate match of its very limited native range (CLIMEX software) to California, but not to the southeastern USA. It would not be predicted to migrate to the latter region where it might attack non-target native leafhoppers. This restriction is very important because it may reduce the risk factors of releasing this egg parasitoid in California ( de León, Logarzo et al. 2008; Logarzo et al. 2008).

Figures

FIGURES 1–4. Gonatocerus deleoni (female, holotype). 1. Antenna. 2. Propodeum. 3. Mesosoma and metasoma. 4. Forewing.

FIGURES 5–8. Gonatocerus deleoni (male, paratypes). 5. Antenna. 6. Dorsellum and propodeum. 7. Genitalia. 8. Forewing.

FIGURES 9, 10. Gonatocerus spp. (male propodeum, scanning electron micrographs). 9. Gonatocerus deleoni. 10. Gonatocerus sp. near tuberculifemur “Clade 1”.

FIGURES 15–17. Gonatocerus sp. near tuberculifemur “Clade 1” (male from culture at USDA, ARS SABCL, Hurlingham, Buenos Aires, originally from Tunuyán, Mendoza, Argentina). 15. Antenna. 16. Genitalia. 17. Forewing.