A new flesh fly species of Oxysarcodexia Townsend from the Brazilian Atlantic Forest and redescription of Oxysarcodexia xon (Dodge, 1968)

. A new Neotropical species of Oxysarcodexia Townsend (Diptera, Sarcophagidae) from Atlantic Forest of southeastern Brazil, Oxysarcodexia digitata sp. nov., is described and illustrated based on male and female specimens. This new species resembles O. fraterna Lopes, O. nitida Soares & Mello-Patiu, O. notata Soares & Mello-Patiu, O. vittata (Walker), and O. xon (Dodge), but can be distinguished based on differences in phallic elements. Additionally, the male of Oxysarcodexia xon (Dodge, 1968) is redescribed and illustrated, its female is described for the first time, and new records is presented.

Herein, we describe a new species of Oxysarcodexia from the Atlantic Forest of southeastern Brazil related to "xon species-group". As the original description of O. xon is incomplete in relation to the phallic morphology, the male of O. xon is also redescribed and illustrations are provided to enable its safe differentiation from congeneric species. The female of O. xon is described for the first time.

MATERIAL AND METHODS
The studied material comprised males and females, 13 specimens of Oxysarcodexia digitata sp. nov. and ten specimens of O. xon, housed in the Entomological Collection of the Museu Nacional, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil (MNRJ). Unfortunately, part of examined material cited herein, including five paratypes of the new species and nine specimens of O. xon, was lost in the fire of September 2 nd , 2018 at the MNRJ, and it is indicated as [lost] in the list (Duarte, 2019 Pape (2000), except the terms "median stylus", "paraphallus" and "anterior juxtal margin", which follow the concept of Giroux et al. (2010), Whitmore et al. (2013) and Souza & Buenaventura (2016), respectively, and the terminology of female terminalia follows Mello-Patiu & Santos (2001). Label of holotype of Oxysarcodexia digitata sp. nov. are cited verbatim, lines separated by a slash, different labels by a double slash, comments or corrections in square brackets. New records of Oxysarcodexia xon are indicated with an asterisk in geographic distribution.
Terminalia were dissected, cleared in a hot 10% KOH solution, and neutralized in an acetic acid-ethanol solution. They were temporarily mounted in glycerin on glass slides, observed, and illustrated using a MOTIC K400® stereomicroscope and a ZEISS M80® microscope, both with camera lucida. After study, the dissected terminalia were placed in microvials filled with glycerin and pinned with their respective specimens. Photographs were taken with a Leica DFC450C digital camera mounted on a Leica M205 stereomicroscope and final composite images were digitally stacked by the software Leica Application Suite version 4.8.0. Images were edited using Adobe Photoshop CS6® and Adobe Illustrator CS6® (Adobe Systems, Inc., San Jose, CA).  Diagnosis: Male pregonite with flat triangular projection in the ventral margin ( Fig. 1D), postgonite with a short median seta (Fig. 1D) and anterior juxtal margin as peculiar folded digitate lobes (Figs. 1C-D, 3C, 3E), and vesica with four extensions, X-shaped, in ventral view (Fig. 1C). Female T6 divided in two sclerotized plate (Figs. 2A-B), T8 absent, ST8 short, with a rounded, setose, and poorly delimited apical area ( Fig. 2A), and vaginal plate membranous and poorly delimited (Fig. 2B).
Head: Parafacial, fronto-orbital plate and posterior ocular orbits dark brown with intense golden pruinosity (Figs. 3A-B); parafacial with a row of setulae close to the eye; face with golden slightly silvery pruinosity; facial ridge dark brown with short setulae in the inferior half; frons about 0.23-0.24x head width at level of ocellar triangle; frontal vitta brownish; 9-11 well-developed frontal setae reaching the apex of pedicel; reclinate orbital seta present and more developed than the largest frontals, proclinate orbitals setae absent; ocellar setae as developed as the upper frontals; postocellar setae and paravertical setae of same size of the ocellar setae; inner vertical seta 3X the outer one; gena with golden pruinosity and black setae; postgena gray slightly silvery pruinose with a few black setae anteriorly and pale setae in the rest; post-cranium with two rows of black occipital setae on upper part and pale setae below; antenna dark brown (Fig. 3A), first flagellomere with silvery pruinosity and approximately 2.5x longer than pedicel; arista long plumose on basal ¾; palpus dark brown (Fig. 3A). Distribution: Brazil (Rio de Janeiro, São Paulo).

Etymology:
The species epithet is derived from the Latin digitata (adjective, feminine), meaning fingers, in allusion to the ornamentation of anterior juxtal margin in the phallus, which forms a digitate lobe.   (Walker), and O. xon. The male terminalia of these species have postgonite with a short median seta, unlike most species of Oxysarcodexia that show long median seta, and the anterior juxtal margin with serrate or digitate edge, not straight. It differs from other species by the peculiar pregonite with a flat triangular projection in the ventral margin (Fig. 3D), the anterior juxtal margin with an edge conspicuously digitate (Figs. 1C-D, 3C, 3E) and the vesica X-shaped in ventral view (Figs. 1C-D, 4C).
Female (n = 1). Length: 8 mm. Differs from male as follows: Head: Frons about 0.28x head width at level of ocellar triangle; 2 proclinate orbital setae similar to or slightly shorter than the reclinate orbitals; outer vertical seta slightly shorter than the inner one. Thorax: Mid femur without ctenidium. Abdomen: T5 with about 14 marginal setae; posterior margin ventrally opened (Fig. 5F). Terminalia: T6 divided as two short plates largely separated from each other, with a broad area between them and the posterior margin of T5, internal margin of the plates with a row of strong marginal setae (Fig. 5F); spiracles 6 in the intersegmental membrane and spiracles 7 in tergal plate; T7 and T8 absent; ST6 with numerous marginal setae; ST7-ST8 fused, ST7 with some posterior  setae; ST8 short with a rounded and setose apical area; epiproct membranous with one pair of setae; hypoproct broad with long setae; cercus large and rounded.

DISCUSSION
Early authors considered Oxysarcodexia species with apical phallic enlargement under the distinct genus Xarcophaga (Dodge, 1968, Lopes, 1982, but current authors have dealt with these species under Oxysarcodexia, following the synonymic proposal of Lopes (1975a) and Pape (1996), although species with phallic enlargement have been referred as "Xarcophaga group" or "xon species-group" (Soares & Mello-Patiu, 2010;Souza & Paseto, 2015;Souza & Buenaventura, 2016;Dufek & Mulieri, 2017). However, until now there is no formal proposition between species-groups or subgenera in Oxysarcodexia. Indeed, Oxysarcodexia has been included in some phylogenetic analysis based on morphological or molecular data (Giroux et al., 2010;Kutty et al., 2010;Stamper et al., 2013;Piwczyński et al., 2014;Buenaventura & Pape 2015, but most of them only included species of Oxysarcodexia sensu strictu and no representatives of Xarcophaga, Hybopygia, or Apelophyla in order to test the position of these taxa in this huge genus or monophyletic species-groups, except for the phylogeny by Buenaventura & Pape (2017), who also included one representative of Hybopygia, which was deeply nested in the monophylum of genus Oxysarcodexia, but did not allow a monophyly test of the "xon species-group".