A new genus and species of Neotropical gregarious braconine parasitoid (Hymenoptera: Braconidae) of a caterpillar (Lepidoptera: Hesperiidae) Author Quicke, Donald L. J. Integrative Ecology Laboratory, Department of Biology, Faculty of Science, Chulalongkorn University, Pathumwan, Thailand Center of Excellence in Entomology: Bee Biology, Diversity of Insects and Mites, Chulalongkorn University, Pathumwan, Thailand. The Hymenoptera Institute, 116 Redlands, CA, U. S. A. https: // orcid. org / 0000 - 0002 - 3994 - 7774 Author Sharkey, Michael J. Author Janzen, Daniel Department of Biology, University of Pennsylvania, Philadelphia 19104, U. S. A. & https: // orcid. org / 0000 - 0002 - 7335 - 5107 Author Hallwachs, Winnie Department of Biology, University of Pennsylvania, Philadelphia 19104, U. S. A. & https: // orcid. org / 0000 - 0002 - 5166 - 809 X Author Hebert, Paul D. N. Centre for Biodiversity Genomics, Biodiversity Institute of Ontario, University of Guelph, Guelph, ON, Canada. Author Butcher, Buntika A. Integrative Ecology Laboratory, Department of Biology, Faculty of Science, Chulalongkorn University, Pathumwan, Thailand Center of Excellence in Entomology: Bee Biology, Diversity of Insects and Mites, Chulalongkorn University, Pathumwan, Thailand. The Hymenoptera Institute, 116 Redlands, CA, U. S. A. https: // orcid. org / 0000 - 0002 - 3994 - 7774 text Zootaxa 2020 2020-07-17 4816 3 370 376 journal article 21441 10.11646/zootaxa.4816.3.7 5e685a24-07b3-4644-96a2-9042b8e4cd19 1175-5326 3954495 89561BC9-48B7-45AA-BFD4-BD29F090B5BF Acgorium Sharkey & Quicke gen. nov. Type species: Acgorium felipechavarriai Sharkey n. sp. Diagnosis. This ectoparasitic gregarious wasp differs from all New World Braconinae except for the Nearctic genus Lapicida Quicke in that Acgorium gen. nov . has a complete lamelliform midlongitudinal propodeal carina. It differs from Lapicida in that Acgorium has the median area of the metanotum smooth and without a midlongitudinal carina ( Lapicida has a complete midlongitudinal carina). More reliably, it differs from all other Braconidae or other insects by the distinctive COI DNA barcode and BIN of the holotype . Description. Head: Terminal flagellomere pointed. Scapus slightly shorter ventrally than dorsally in lateral aspect. Dorsal margin of clypeus indicated by a groove, not carinate. Ventral margin of clypeus (above hypoclypeal depression) not produced. Labio-maxillary complex not elongate. Malar suture absent. Eyes glabrous. Frons flat behind antennal sockets, weak midlongitudinal carina extending from median ocellus to interantennal space. Mesosoma: Mesoscutum smooth; notauli smooth, barely indicated, and not greatly converging posteriorly. Scutellar sulcus moderately wide, crenulate (with five crenulae). Median area of metanotum smooth without midlongitudinal carina. Precoxal sulcus absent. Propodeum smooth with well-defined midlongitudinal carina. Femora of normal dimensions. Length of hind tibia subequal to tarsus; without longitudinal lateral groove. Claws with a sharp to squared basal lobe. Wings: Fore wing 2 nd submarginal cell narrowed apically, 3x longer than high at maximum lengths. Vein 1RS forming an angle of 45 degrees with C + SC + R. Vein (RS + M)a straight. Vein (RS + M)b as long as or slightly longer than m-cu. Vein 2CUa straight except for slight posterior angulation, not thickened posteriorly. Hind wing vein C+SC+R with one basal hamulus. Vein R short, as long as it is thick. Base of hind wing densely and evenly setose. Vein cu-a, reclivous, slightly curved. Vein 2-1A absent. Metasoma: Metasomal terga heavily sculptured with 8 visible terga, the last two of which are mostly concealed. Anterior surface of first metasomal tergum mostly vertical. First metasomal tergum with well-developed dorsal carinae that reach posterior margin separately, dorsope and laterope absent. Second tergum lacking mid-basal triangular area but with midlongitudinal carina and with pair of anterior, submedial raised, semicircular areas. Second suture deep and crenulate. Third tergum without demarked anterolateral areas. Terga 3-5 without subposterior transverse groove. Penultimate metasomal sternum heavily sclerotized and swollen apically. Ovipositor short, barely exerted, extremely slender, without obvious pre-apical dorsal nodus or ventral serrations. Biology. The only species in our new genus, A. felipechavarriai , is a gregarious parasitoid of Dyscophellus phraxanor (Hesperiidae) feeding on mature leaves of Virola sebifera ( Figs 2 and 3 ). The host caterpillars of the other nine rearing records of this species, previously incorrectly called “ Bracon felipechavarriae ”, were feeding on this plant, V. koschnyi or Otoba novogranatensis (Myristicaceae) . All 2,105 rearing records of wild-caught D. phraxanor caterpillars are from ACG rain forest at intermediate elevations on the Caribbean slope of Cordillera Guanacaste , northwestern Costa Rica and have generated 72 parasitoid and hyperparasitoid rearings of other species of Tachinidae and Hymenoptera ( Janzen and Hallwachs 2016 , 2019a ). Remarks/Relationships. The combination of an antennal scape shorter ventrally than dorsally (in lateral aspect), simple basal flagellomeres, and claws with large square or pointed basal lobe place the new genus in the Braconini . The combination of a complete lamelliform midlongitudinal propodeal carina, strong dorsal carinae of the first metasomal tergite, flexibly articulated junction between tergites 1 and 2, and six strongly sculptured meta- somal tergites suggests a possible relationship with the Plesiobracon Cameron group of genera (Achterberg 1983; Quicke 1988 ), a group that is otherwise only known from the Old World (almost entirely from the tropics). Most genera assigned to this group also have the mesoscutum densely and evenly short setose, but that character is absent in the new genus and partial in a few groups that appear on other grounds to be members of the Plesiobracon group ( Quicke 1988 ). Whether the Plesiobracon group is indeed monophyletic (with or without inclusion of the apparently closely-related Aspidobraconina (which share all their synapomorphies but additionally have tergites 1 and 2 fused) has not been tested yet with molecular phylogenetics. Therefore, another possibility is that the propodeal carina, strongly carinate first metasomal tergum, six heavily sculptured metasomal terga and short ovipositor are a syndrome of characters associated with some particular biological feature, such as an aspect of oviposition behavior. Interestingly, members of the Aspidobraconina as well as at least one member of the Plesiobracon group s.s. are parasitoids of butterflies (Rhopalocera) including Hesperiidae , but as endo- rather than ectoparasitoids (Gupta et al. 2016). FIGURE 1 . Acgorium felipechavarriai Sharkey sp. nov. , holotype, DHJPAR0059752, one of 43 presumed sibs reared from the last instar caterpillar of wild-caught Dyscophellus phraxanor caterpillar 16-SRNP-30739 ( Janzen and Hallwachs, 2019a ). A, habitus lateral view; B, face; C, habitus, dorsal view; D, mesosoma lateral view; E, wings (paratype); F, scutellum to metasomal tergite 2, oblique dorsal view. FIGURE 2. Last instar Dyscophellus phraxanor (Hesperiidae) caterpillar 09-SRNP-561 being exsanguinated and therefore killed by a brood of at least 29 presumed sibs of Acgorium felipechavarriai sp. nov. (09-SRNP-561-DHJ452257.jpg). These last instar wasp larvae continue to be attached and feed externally within the silked leaf shelter made by the caterpillar (non-infected caterpillars forage out on the leaf surfaces to feed at night). They are wet from exuded blood and perhaps other fluids. Etymology. Acgorium is named in honor of Área de Conservación Guanacaste , northwestern Costa Rica , to celebrate its 35 years of experimentation with converting a classical national park to a government-NGO hybrid collaboration for tropical biodiversity conservation through non-damaging biodevelopment ( Janzen and Hallwachs 2019b ).