A new species of Austrocodrus Ogloblin (Hymenoptera, Proctotrupidae, Austroserphinae), a Gondwanic relict from southernmost South America

Abstract Austrocodrusgladiogeminussp. n. is described from southernmost South America. It is a member of the primitive subfamily Austroserphinae (Hymenoptera, Proctotrupidae), which is distributed in Oceania and South America, and is characterized from other Austrocodrus species by its relatively larger body size, the presence of long and sword-shaped ovipositor sheaths, M arising very close and distal to 1cu-a, and Cu and m-cu joining at a distance equivalent to the length of 2cu-a. We consider this species to be a Gondwanan relict. It has southernmost distribution of any proctotrupid.


Introduction
The parasitic wasp family Proctotrupidae includes about 600 species and 30 genera in two subfamilies: Proctotrupinae and Austroserphinae (= Acanthoserphinae; Townes and Townes 1981). These subfamilies show a strong imbalance in their diversity. The subfamily Austroserphinae, from continental Australia, New Guinea, Tasmania, and southern South America, has three genera with four species, but Proctotrupinae has cosmopolitan distribution and the vast majority part of the family's diversity (Townes and Townes 1981;Johnson 1992). The first described species of Austroserphinae was Acanthoserphus albicoxa (Dodd 1915), which was described from material collected in Queensland, Australia, and subsequently, Masner in Townes and Townes (1981) described Acanthoserphus bidens from Papua New Guinea. Dodd (1933) also described Austroserphus albofasciatus, in a new genus, from material collected in Victoria, Australia. In his revision of Australian proctotrupids, Riek (1955) reported new records for Austroserphus albofasciatus from Tasmania. Ogloblin (1960) described the only South American species known to the date for the subfamily, Austrocodrus patagonicus. Austrocodrus was originally placed as a subgenus of Austroserphus but later raised to the status of genus by Townes and Townes (1981). Ogloblin (1960) described A. patagonicus based on specimens collected at Estación Forestal de Pucará, near Lago Lácar, Neuquén, Argentina (40°10'S, 71°27'W). In a revision of material from southernmost Chilean Patagonia, roughly 1700 km south of the type locality of A. patagonicus, one specimen belonging to the genus Austrocodrus was collected which could not be ascribed to A. patagonicus. Based on this material, we describe a second species of Austrocodrus, which is the southernmost known proctotrupid.

Material and methods
The material examined is deposited in the Museo de Zoología de la Universidad de Concepción, Concepción, Chile (MZUCCC 45974). Photographs were made with a Nikon SMZ 745T stereomicroscope and a Nikon D5100 camera using a NII-LED Nikon illuminator. Individual images were stacked with Zerene Stacker Software (2017). The habitus photograph was taken with an AF-S Micro Nikkor 105 mm 1:2.8 G ED lens, and illuminated with Nikon Speedlight SB-800.

Family
Mesosoma. Pronotum dorsally occluded by mesoscutum and not visible in dorsal view. Epomium strong, which are connected dorsally by carina. First anterodorsal portion of pronotum shiny, smooth, the remainder strongly reticulated, sparsely pilose. Mesoscutum with notauli narrow, deep, originating from the anterior margin not reaching mesoscutellum. Groove in front of mesoscutellum with 7 foveae (Fig. 2D). Scutellum 1.3 × as wide as long, with glabrous center. Axillae deep, sculptured. Metanotum well developed, 1.2 × as long as mesoscutellum, with median section elevated and subtriangular. Axillary trough of metanotum sculptured. Wings hyaline, pilose, with the major part of veins tubular. Anterior portion of M nebulous. Also, M arising close and apical to 1cu-a. Cu and m-cu joining at a distance equal to the length of 2cu-a (Fig. 2B). Propodeum with a short distinct transverse carina on the anterior margin which connects with irregular lateral longitudinal carinae. Petiolar area separated from dorsal propodeum by a strong transverse carina, laterally delimited with low developed apophysis. Propodeum strongly reticulate, pilose and with a raised bare lateral area. Propodeal spiracle elongated, declined 15° from a transverse plane tangent to its ventral end. Propleura flat and strongly pilose. Mesopleuron with prepectus sparsely rugulose and pilose. Prepectal area separated from central mesopleuron by a foveate groove.  Central mesopleuron swollen, bare and shiny. Mesopleural suture anteriorly foveate with similar size foveae. Mesepisternum narrow and bare. Mesosternum slightly swollen, strongly pilose. Mesepimeron and mesosternum separated anteriorly by delicate carina anteriorly. Petiole present, with longitudinal wrinkles, 0.3 as long as high.
Male. Unknown. Distribution, habitat and behavior. The type locality of A. gladiogeminus sp. nov. is on the northern coast of Isla Navarino, in the glacially fragmented landscape of southernmost Chile, and lies within the Magellanic Forest biogeographical province in the Subantarctic subregion of the Andean region (sensu Morrone 2015). The new species was collected from a Subantarctic Nothofagus forest, dominated by Nothofagus pumilio (Poepp. & Endl.) Reiche, and came from a microhabitat of open mixed forest with old and young N. pumilio trees. The specimen was collected with a net while flying during an afternoon of the austral summer.
Etymology. The epithet gladiogeminus refers to the exceptionally sword-shaped ovipositor sheaths. It is a composition from the Latin noun "gladius", a sword, the basic weapon of Roman legionnaires after the Punic Wars, and the adjective "geminus", double or paired.
Remarks. Austrocodrus gladiogeminus sp. nov. is the first record of an austroserphine from Chile, and only the second record of the subfamily from South America. Other than the two species of Austrocodrus, all other species of the subfamily are distributed in Australia and few southern Pacific islands, which suggests that Austrocodrus is a relict of the past connection between these land masses. Additionally, A. gladiogeminus sp. nov. has the southernmost distribution of any proctotrupid, reaching almost the 55°S.
The body size of the holotype, with a fore wing length of 5.84 mm, might be the largest among species of the subfamily; the forewing length of A. patagonicus is about 3.7 mm, in species of Acanthoserphus, between 3.1 and 3.7 mm, and in Austroserphus between 5.3 and 5.8 mm. Additionally, we find that the venation pattern of the genus Austrocodrus is not so similar to that of Acanthoserphus (sensu Townes and Townes 1981). The relative position of M basal to 1cu-a in Acanthoserphus and Austroserphus allows differentiating these genera from Austrocodrus, which has 1cu-a basal to M.
We provide a key to species of the genus Austrocodrus (Ogloblin 1960): 1 M vein tubular, arising apical but not close to 1cu-a. Cu and m-cu joining a short distance in front of 2cu-a. Groove in front of scutellum with 5 foveae. Gaster tapered. Head, mesosoma and metasoma black ........... A. patagonicus Ogloblin -Anterior segment of M vein nebulous. Also, M arising very close and apical to 1cua. Cu and m-cu joining at a distance equal to the length of 2cu-a ( Figs. 1 and 2b). Groove in front of scutellum with 7 foveae (Fig. 2d). Gaster anteriorly swollen tapering very strongly toward posterior apex (Fig. 1). Head and mesosoma black; gaster bicolored, brown at dorsally and creamy white at ventrally (Fig. 1)