First records of Sepedonea lindneri ( Hendel , 1932 ) and Protodictya lilloana Steyskal , 1953 ( Diptera , Sciomyzidae ) from Uruguay with an overview on their biology

Sciomyzidae (Diptera) has been recorded in several countries of South America, but few species have been found in Uruguay. We report the first record of Sepedonea lindneri (Hendel, 1932) and Protodictya lilloana Steyskal, 1953 (Diptera, Sciomyzidae) from Uruguay. The specimens were collected in rice crops and in adjacent native vegetation with sweep net and vacuum sampler from December to March (2012–2015) in the Eastern region of the country. Photos of collection areas, habitus of adults and distribution map of the species are provided.


Introduction
The Sciomyzidae (Diptera) are commonly known as marsh flies or snail-killing flies.They are the only family formed almost exclusively by obligate killers of mollusks (Marinoni andKnutson 2010, Chapman et al. 2012).Within the Diptera, Sciomyzidae is the family of greatest relevance as biocontrol agent of gastropods (Gormally 1988, Maharaj et al. 1992, Barker et al. 2004, Marinoni and Knutson 2010, Kirst et al. 2015).
Species of this family are small to moderately large and range from 1.8 to 11.5 mm in length.Their color varies from shiny black to dull gray, brown, yellowish or reddish.Wings are often patterned.Legs are often elongated and antennae elongated and prorrect (Knutson 1987b).Sciomyzid flies are recognized by the absence of oral vibrissae, postocellar setae parallel or slightly diverging, costa entire, subcostal complete, one or more tibia with preapical setae (Barker et al. 2004).
The family Sciomyzidae comprises more than 600 species in approximately 63 genera distributed worldwide, with a higher diversity recorded from temperate regions (Vala et al. 2012, 2013, Marinoni and Mathis 2006, Marinoni and Murphy 2016).In the Neotropical Region, the number of taxa described is 103 species in 25 genera (Berg and Knutson 1978, Knutson 1987a, b, Marinoni and Mathis 2000, Marinoni and Murphy 2016).The fauna of Sciomyzidae from Uruguay is poorly known.The only report corresponds to that by Marinoni and Murphy (2016) who reported Perilimnia albifacies Becker, 1919 andSepedomerus bipuncticeps (Malloch, 1933) from Montevideo.Since then, additional species were not described or recorded for this country.The aim of this study was assessing the arthropod diversity associated to rice crop.
We report Sepedonea lindneri (Hendel, 1932) and Protodictya lilloana Steyskal, 1953 for the first time in Uruguay.New studies and surveys will undoubtedly increase the number of sciomyzid species known for this country.

Methods
This study was conducted in the Treinta y Tres province, Eastern region of Uruguay, from December 2012 to November 2015.The adult sciomyzids were collected with a sweep net and vacuum sampler during a biodiversity project carried out on rice agroecosystem in 4 localities: Julio María Sanz (33°11ʹ54.99ʺS, 054°05ʹ12.30ʺW), El Tigre (33°13ʹ27.80ʺS, 053°59ʹ38.84ʺW), General Enrique Martínez (33°12ʹ08.15ʺS, 53°50ʹ47.98ʺW) and Paso de la Laguna (33°16ʹ27.07ʺS, 054°09ʹ53.52ʺW) (Fig. 12).The Eastern region of Uruguay is one of the most important cultivated areas (ACA 2013).It is located within the Bañados del Este, a wetland area that belongs to an international protected area by the RAMSAR convention (PROBIDES 1999).Different aquatic environments were sampled.Collecting was done near a small river bordering the rice crops (Fig. 1).Also, natural areas with temporary ponds and aquatic plants formed during the rainy season (Fig. 2) were sampled, as well as disturbed margins and surroundings with the vegetation altered, such as pastures (Figs 3,4).Rice crop and native vegetation surroundings (NV: riparian forest patches) were also sampled.Collections with an aerial net were made by vegetation sweeping.The net was used along the crop, doing 8 transects of 20 sweeps by location.Vacuum sampler was used to aspirate at 15 points, for 60 seconds in each location.
Collected flies were placed into plastic vials with 70% ethyl alcohol and taken to the Entomology Laboratory of Facultad de Agronomía (Montevideo) where they were prepared for identification.The adults were identified following the taxonomic keys by Steyskal and Knutson (1975), Freidberg et al. (1991), Marinoni and Knutson (1992), Marinoni and Mathis (2006).Voucher specimens were deposited at the Entomological Collection of Facultad de Agronomía, Universidad de la República (Unidad de Entomología, Montevideo, Uruguay) and Entomological Collection, "Padre Jesus Santiago Moure," Department of Zoology, Universidade Federal do Paraná (DZUP).
The habitus illustrations are digital photographs taken from a lateral view with a stereoscopic microscope Konus Crystal 45 with a Dino-Eye Microscope Eyepiece Camera, enhanced using Photoshop CS6 to adjust the color and make minor corrections (e.g.remove debris).
Distribution maps were made using Quantum GIS 2.8.Longitude and latitude were obtained for each locality where specimens were collected using a GPS GARMIN Etrex and were entered into a Microsoft Excel spreadsheet.Localities of specimens were plotted on a world land projection, presented within ESRI ArcView layouts, and exported as encapsulated postscript (EPS) files.

Results
A total of 28 specimens of marsh-flies belonging to the genera Sepedonea Steyskal and Protodictya Malloch were collected and identified.Sepedonea lindneri (Hendel, 1932) and Protodictya lilloana Steyskal, 1953 are reported for the first time for Uruguay (Table 1).

Protodictya lilloana
Identification.According to Freidberg et al. (1991), adults of S. lindneri are usually yellow to dark brown, with a lateral facial spot on the head (Fig. 7).Postocellar setae well developed and ocellar seta absent (Fig. 6).The mesonotum is usually grayish black (Figs 5,6).Mid femur postero-ventrally with 4-7 spines.Hind femur with dark lateral and rounded dorsal preapical spots (Fig. 8).Wings are grayish hyaline, with indistinct clouds on crossveins r-m and dm-cu (Fig. 5).This species has the southernmost distribution of all congeners and can be differentiated from other species of the genus using the key in Freidberg et al. (1991).Protodictya lilloana can be identified using the key in Marinoni and Knutson (1992).Adults are dark brown with a frontal facial black spot in the anterior half (Figs 10,11).The antenna with third antennomere apically darkened bearing a plumose arista.Wings have apical hyaline spots in cells r 2+3 and r 4+5 aligned (Fig. 9).

Discussion
Sepedonea and Protodictya are widely distributed in the Neotropical Region, mainly in Brazil (Marinoni and Knutson 2010).Sepedonea with 13 species and Protodictya with 8 species are within the richest sciomyzid genera in neotropical areas (Marinoni andKnutson 2010, Kirst et al. 2015).However, few species of Sciomizydae Both species are predators of non-operculate snails in different freshwater situations and are strictly neotropical (Knutson andValley 1978, Freidberg et al. 1991, Marinoni personal communication).These species belong to the same eco-group defined by Barker et al. (2004), the group that inhabits in benthic freshwater, estuarine littoral habitats and in wetlands to dry land habitats.Oviposition takes place on prey or habitat substrates, and first instar larvae feeding behavior ranges from saprophagous scavenger, to polyphagous predator or parasitoid, or oligophagous parasitoid.
Considering the potential hosts present in the habitats surveyed, it is worth mentioning the golden apple snail Pomacea canaliculata (Lamarck, 1822) (Gastropoda, Ampullariidae) as a species commonly found in Uruguay (Hayes et al. 2012).Pomacea canaliculata became a rice pest in the Asiatic continent after its introduction as human food or exotic snails in aquarists' shops (Joshi 2005, Murphy et al. 2012).Pomacea canaliculata is prey of certain sciomyzid larvae in the Nearctic Region in freshwater habitats (Foote et al. 1999).
The species S. lindneri and P. lilloana recorded for Uruguay in this work, can play an important role in the biological control of this snail pest in rice crops in Uruguay.Given the type of habitat and host/prey required by sciomyzids and the rice cultivation under flooding, the crop could be considered as a biological corridor for these species.Both species are closely associated with semi-aquatic environments where they develop and find their hosts.More research should be conducted with the aim of knowing the host snail species that the 2 sciomyzid species reported here have the potential to control, considering that P. canaliculata is not a pest at present in Uruguay but causes severe damages in invaded Asiatic fields (Joshi 2005, Murphy et al. 2012).

Table 1 .
Sciomyzid species and collecting data.Abbreviations: N = number of specimens collected, NV = native vegetation patches adjacent to rice crop.