Gryon aetherium Talamas, 2021

Talamas, Elijah J., Bremer, Jonathan S., Moore, Matthew R., Bon, Marie-Claude, Lahey, Zachary, Roberts, Cheryl G., Combee, Lynn A., McGathey, Natalie, van Noort, Simon, Timokhov, Alexander V., Hougardy, Evelyne & Hogg, Brian, 2021, A maximalist approach to the systematics of a biological control agent: Gryon aetherium Talamas, sp. nov. (Hymenoptera, Scelionidae), Journal of Hymenoptera Research 87, pp. 323-480 : 323

Gryon aetherium Talamas sp. nov.

Figures 5 , 9 , 15-16 , 54-57 , 58 , 59-66 , 67-72.

Description.

Color of body: dark brown to black. Color of legs: coxae and femora brown; trochanters, tibiae and tarsi yellow to pale brown.

Color of antenna in female: yellow to pale brown, A9-A12 generally darker than preceding antennomeres.

Head: Number of mandibular teeth: 2. Shape of mandibular teeth: large, teeth roughly equal in size. Shape of clypeus: projecting ventrally, apex flat to convex, with sharp lateral corners. Number of clypeal setae: 6. Epiclypeal carina: absent. Facial striae: present as lines of microsculpture. Central keel: present. Line of setae above interantennal process: absent. Malar striae: present as lines of microsculpture. Genal carina: absent. Hyperoccipital carina: absent. Anterior margin of occipital carina on gena: smooth. Occipital carina: present dorsally and in ventral portion of gena, absent or weakened posterodorsal to compound eye.

Mesosoma: Epomial carina: absent. Sculpture of lateral pronotum: reticulate microsculpture. Netrion sulcus: absent. Mesoscutal suprahumeral sulcus: absent. Mesoscutal humeral sulcus: absent. Sculpture of mesoscutum: reticulate microsculpture.

Sculpture of mesoscutellar disc: reticulate microsculpture. Posterior mesoscutellar sulcus: foveate. Posterior margin of mesoscutellum: extending over metanotum, metascutellum not visible in dorsal view. Posterior margin of metascutellum: slightly convex. Sculpture on posteroventral surface metascutellum: weakly rugulose. Sculpture of metanotal trough: foveate. Length of postmarginal vein in fore wing: about 1.5 times as long as stigmal vein. Length of marginal vein in fore wing: about half as long as stigmal vein. Wing color: hyaline with transverse band of infuscation posterior to marginal vein. Shape of submarginal vein: straight in basal 4/5, with dip proximal to reaching wing margin.

Lateral propodeal carina: continuous across posterior propodeum, forming flange around metasomal depression. Sculpture of metasomal depression: weakly rugulose. Sulcus of the propodeal foramen: foveate dorsally, absent ventrally. Cells or foveae along ventral margin of mesopleural carina: absent. Posterior limit of acetabulum: acetabular carina intersecting with ventral mesopleural carina. Postacetabular sulcus: foveate. Mesopleural epicoxal sulcus: foveate. Episternal foveae: present. Mesopleural carina: absent; present only at ventral apex of femoral depression. Sculpture of anteroventral mesopleuron: reticulate microsculpture. Sculpture of femoral depression: smooth. Prespecular sulcus: foveate. Sculpture of speculum: finely striate. Shape of subalar pit: circular. Mesepimeral sulcus: comprised of transverse foveae, foveae absent or reduced in size posterior to speculum. Sculpture of posterior mesepimeral area: smooth. Paracoxal sulcus: indicated by transverse foveae, extending below metapleural pit but not to ventral margin of metapleuron. Metapleural epicoxal sulcus: indicated by crenulae or indistinguishable from rugose sculpture. Metapleural structure: not divided into anterior and posterior areas. Sculpture of dorsal metapleural area: transversely striate. Sculpture of ventral metapleural area: irregularly rugose.

Metasoma: Macrosculpture of T1: longitudinally striate, smooth along posterior margin. Setation of T1: present lateral and posterior to lateral pit of T1. Setation of T2-T5: dense in lateral part of tergite, absent medially except for a transverse line of sparse setae along posterior margin. Posterior margin of T6: concave. Sculpture of T2-T4: finely reticulate with a smooth band along posterior margin. Sculpture of S2: finely reticulate. Setation of laterotergites: present. Transverse sulcus on anterior S2: present as a line of small foveae.

Etymology.

The species epithet " Gryon aetherium " derives from Latin, meaning of the sky or heavens, and refers to the unexpected appearance of this species in North America, far from its native range.

Diagnosis.

Gryon aetherium is best separated from other Gryon species by the following characters: mesopleural carina entirely absent or present only at ventral apex of mesopleuron; posterior margin of mesoscutellum protruding posteriorly, concealing metascutellum and metanotal trough in dorsal view; mesopleuron with two episternal foveae; foveae of mesepimeral sulcus attenuating in size dorsally, foveae small or undefined posterior to speculum; acetabular carina and ventral mesopleural carina intersecting ventrally; metapleuron not transversely striate throughout; fore wing with infuscation posterior to marginal vein; hind tibia with four subgenual spines; lateral propodeal carina horizontal, extending laterally to metapleural carina.

In North America, Gryon aetherium is most similar to G. myrmecophilum , from which it is most easily separated by the mesopleural carina: complete in G. myrmecophilum , extending from the posteroventral apex of the femoral depression to the anterior margin of the mesopleuron; absent or present only at ventral apex of mesopleuron in G. aetherium . This character also serves well to separate G. aetherium from G. gonikopalense (Figures 77-78 ) G. fasciatum (73-76), and G. oligomerum Kononova, which are Old World species that are very similar to G. aetherium but have a complete mesopleural carina.

Intraspecific variation.

Non-target testing of G. aetherium in quarantine enabled us to examine how different hosts affect the phenotype of the parasitoids. Overall, we found very little variation between specimens of G. aetherium reared from Bagrada hilaris , Thyanta custator , Holcostethus , Banasa sordida and Euschistus conspersus (Figures 67 , 69-72 ). The sculpture of the dorsal metapleural area varies from transversely striate to irregularly rugose. The foveae that comprise the mesepimeral sulcus decrease in size dorsally, and posterior to the speculum these foveae can be small and circular or poorly defined. Only one male specimen emerged from eggs of Banasa sordida (Figure 71 ), which was unusual in that the femoral depression was faintly microsculptured and the foveae of the paracoxal sulcus were shallow and not well-defined. This specimen also had malformed antennae, suggesting that Banasa sordida is not a suitable host for G. aetherium .

Prior misidentifications.

Gryon aetherium was misidentified twice by the first author: as G. gonikopalense in Martel et al. (2019) and this name was subsequently used in Martel and Sforza (2021), Tofangsazi et al. (2020) and Hougardy and Hogg (2021), and as G. myrmecophilum in Felipe-Victoriano et al. (2019). The morphological limits of G. aetherium were unclear at the time that these names were used, resulting in a hesitancy to describe it as a new species, especially because not all relevant types had been examined.

Adventive populations.

As implied by the previous paragraph, G. aetherium has been present in Mexico since at least June of 2018 and the study by Felipe-Victoriano et al. (2019) is thus the first record of this species in North America. It appears that G. aetherium has been in the United States for a similar length of time given that specimens were recovered from two locations in California: Davis, Yolo County, in 2020, and Monterey County, in 2018 and 2019. In both cases the specimens were reared from B. hilaris sentinel egg masses. A specimen from the 2018 collection (FSCA 00033319:PL11) was sequenced to confirm its identity (Figure 4 ). It differed from the quarantine populations by three base pairs, alleviating concerns that it represented escapees. The specimens collected in Monterey were stored in isopropanol, which affected the color of the specimens (Figure 68 ) and degraded the DNA. We were not able to amplify COI from the specimens collected in Monterey, but our morphological analysis using scanning electron microscopy finds them to be identical to the specimens in quarantine and those that were retrieved in Yolo County. In 2021, a population of G. aetherium was recovered in Chile, reared from the eggs of B. hilaris ( Rojas-Gálvez et al. 2021).

Material examined.

Holotype, female: Pakistan: Punjab, Toba Tek Singh, Dabanwala leg. R. Mahmood, coll. 5-9.IV.2016, ex. eggs Bagrada hilaris 11-V-2016 on mustard, introduced to quarantine for EBCL colony, PP8, USNMENT01335778 (deposited in USNM) . Paratypes (72 females, 37 males): Mexico : 9 females, 3 males, FSCA 000900442-00090443, 000900446-00090447, 000900468-00090475 (FSCA). Pakistan : 19 females, 8 males, FSCA 00033215-00091216, 00091221, 00094940-00094944, 00094984-00094992; USNMENT00989933, 01109043, 01109046-01109047, 01109049, 01109052, 01109054-01109155, 01335774, 01335776 (USNM). United States : 44 females, 26 males, FSCA 00033319, 00090933, 00091210, 00091217,00091930, 00094869, 00094871, 00094873-00094874, 00094877, 00094885, 00094899, 00094901-00094903, 00094945- 00094981, 00094983, 00094993-00095009 (FSCA).

Figures

Figure 4. Phylogenetic relationships of Scelionidae based on a maximum likelihood analysis of 479 COI sequences. Branches in blue and red indicate Hadronotus and Gryon, respectively. Terminals belonging to G. aetherium are shown to the right of the phylogenetic tree. Terminals highlighted in yellow correspond to adventive G. aetherium specimens collected in Mexico and California. Scale bars indicate the expected number of substitutions per site.

Figures 58. Gryon aetherium, female (USNMENT 01109155), habitus, ventrolateral view.

Figures 5 - 8. Scutellar-axillar complex, lateral view 5 Gryon aetherium (USNMENT 01109155) 6 Duta (USNMENT 01109621 _ 2) 7 Hadronotus hogenakalensis (DPI _ FSCA 00008722) 8 Hadronotus carinatifrons (USNMENT 01335649).

Figures 9 - 14. Mesosoma, lateral view 9 Gryon aetherium (FSCA 00094874) 10 Hadronotus hogenakalensis (DPI _ FSCA 00008722) 11 Hadronotus ater (FSCA 00094730) 12 Hadronotus pennsylvanicus (FSCA 00091081) 13 Hadronotus anserculus, holotype female 14 Hadronotus canus, holotype female.

Figures 15 - 20. Metasoma 15 Gryon aetherium (FSCA 00094873), dorsolateral view 16 Gryon aetherium (FSCA 00094873) ventrolateral view 17 Hadronotus bicolor (FSCA 00091193), dorsolateral view 18 Hadronotus bicolor (FSCA 00091193), lateral view 19 Hadronotus carinatifrons (USNMENT 01335649), dorsolateral view 20 Hadronotus carinatifrons, ventrolateral view.

Figures 54 - 57. Gryon aetherium 54 holotype female (USNMENT 01335778), head, anterior view 55 female (FSCA 00090468), wings, dorsal view 56 holotype female (USNMENT 01335778), head, mesosoma, metasoma, lateral view 57 holotype female (USNMENT 01335778), head, mesosoma, metasoma, dorsolateral view.

Figures 59 - 66. Gryon aetherium 59 female (FSCA 00094873), head, anterior view 60 female (FSCA 00094869), head, posterolateral view 61 female (FSCA 00094873), antennal clava, lateral view 62 female (FSCA 00094869), mesosoma, ventral view 63 female (FSCA 00094873), mesosoma, dorsolateral view 64 female (FSCA 00094874), mesosoma, anterolateral view 65 female (FSCA 00094874), mesosoma, posterolateral view 66 female (FSCA 00094871), hind tibia, dorsal view.

Figures 67 - 72. Gryon aetherium, lateral habitus 67 female (FSCA 00094902), ex. Bagrada hilaris 68 female (FSCA 00094885), ex. Bagrada hilaris 69 female (FSCA 00094903), ex. Holcostethus 70 female (FSCA 00094899), ex. Thyanta custator 71 male (FSCA 00094877), ex. Banasa sordida 72 male (FSCA 00094901), ex. Euschistus conspersus.

Figures 77 - 78. Gryon gonikopalense, holotype female (USNMENT 01109129) 77 habitus, lateral view 78 mesosoma, lateral view.