Phylogeny of the old and fragmented genus Austrocoenosia Malloch reveals new evidences on the morphology and evolution of the genera Coenosia Meigen and Neodexiopsis Malloch (Diptera: Muscidae)

Patitucci LD, Mulieri PR, Couri MS, Domínguez MC 2023. Phylogeny of the old and fragmented genus Austrocoenosia Malloch reveals new evidences on the morphology and evolution of the genera Coenosia Meigen and Neodexiopsis Malloch (Diptera: Muscidae). Arthropod Sys-tematics & Phylogeny 81: 611–653. https://doi.org/10.3897/asp.81.e104969 Abstract Coenosiini (Diptera: Muscidae) is a large cosmopolitan tribe of muscids, within which Coenosia Meigen and Neodexiopsis Malloch are the genera with the largest number of species. In this work, we revised for the first time, all the species placed by Malloch (1934) under Austrocoenosia , an endemic genus from the Andean Patagonian Forests, whose species are now placed in Coenosia and Neo-dexiopsis . We provide detail redescriptions for eight species placed by Malloch (1934) under Austrocoenosia , and decribed two new species ( Coenosia delneneo sp. nov. and Coenosia patagonica sp. nov. ), with high quality photographs detailing new structures of the male and female terminalia. To establish the position of the species of Austrocoenosia with respect to Coenosia and Neodexiopsis , we made a phylogenetic analysis using implied weighting for 36 taxa and 132 morphological characters of adults, including male and female genitalia. We recovered all species of Austrocoenosia as Coenosia species. We propose the following nomenclature actions: Austrocoenosia as a junior synonymy of Coenosia ( syn. rest. ); Coenosia brevicornis (Malloch) ( comb. nov. ), Coenosia dubia (Big-ot) ( comb. rest. ); Coenosia hucketti , Pont ( nom. nov. ) and Coenosia nigerrima (Malloch) ( comb. rest. ). We also propose Coenosia spumicola Pont as an unplaced species of Coenosia sensu lato. Finally, we updated the geographic distributions for all species and observed several new male and female terminalia structures, which enriched the discussion of the genera and the tribe.


Introduction
As part of the revision of the muscids of Argentina and Chilean Patagonia (southern South America), Malloch (1934) erected the new genus Austrocoenosia Malloch, 1934, within the tribe Coenosiini (Diptera, Muscidae, Coenosiinae) endemic to areas currently considered as part of the Andean biogeographic region (Morrone 2015). This new genus was differentiated from the larger and cosmopolitan genus Coenosia Meigen, 1826 only by the presence of one seta on the posterodorsal surface of the hind tibia, in addition to the anterodorsal and anteroventral setae present in Coenosia specimens. Austrocoenosia included six new species (Austrocoenosia aurifera Malloch, 1934; Austrocoenosia argentifrons Malloch, 1934; Austrocoenosia brevicornis Malloch, 1934; Austrocoenosia nigerrima Malloch, 1934; Austrocoenosia inusitata Malloch, 1934 and Austrocoenosia projecta Malloch, 1934). Malloch (1934) also added two already known species of Coenosia as part of Austrocoenosia: Coenosia dubia (Bigot, 1885) and Coenosia ignobilis Stein, 1911. Furthermore, Malloch (1934 designated A. nigerrima as the type species of the genus. Several years later, Snyder (1957) described a new species: Limosia tarsata Snyder, 1957, collected at the southern extreme of Argentina based on three specimens (one male and two females). Although this author observed the presence of the posterodorsal seta on the hind tibia of the specimens studied, he found it difficult to assign this species to Austrocoenosia or Coenosia. Snyder (1957) considered that the combination of two preapical setae on the hind femur and the doubtful presence of a posterodorsal seta on the hind tibia were characters similar to those observed in the Nearctic genus Limosia, and consequently assigned tarsata under this genus. Later, in a catalog of the Diptera of the Americas south of the USA, Pont (1972) placed Austrocoenosia as a junior synonymy of Coenosia and established new combinations of most of the species presented by Malloch (1934) and Snyder (1957) under Coenosia with the exception of A. brevicornis, which was placed as a new combination under the New World genus Neodexiopsis Malloch, 1920. In a study of Neodexiopsis specimens housed in the Museu Nacional do Rio Janeiro, Brazil (MNRJ), Couri and Albuquerque (1979) observed one female specimen of C. ignobilis Stein 1911 and one male and several female specimens of A. nigerrima, presented a description of the male terminalia of A. nigerrima, and, based on the results, proposed a new combination of both species (and consequently of Austrocoenosia) under the genus Neodexiopsis. Several years later, the type specimens of C. ignobilis were studied by Pont (2001), who established that the species belonged to Coenosia and not to Neodexiopsis. In a similar way, Couri and Nuñez (2001) provided a redescription of A. argentifrons with details of the male terminalia, and determined that the species belonged to Coenosia. Currently, the species of Austrocoenosia are placed under the genera Coenosia or Neodexiopsis .
The large genus Coenosia, with over 360 species, is known from all biogeographic regions (Sorokina 2009), although according to Couri and Pont (2000) more than 60% of its species are distributed in the Old World. Some species of Coenosia are currently used as biocontrol agents in greenhouses because they prey over white flies, black fungus gnats and leaf-mining flies (Kühne 2000). The generic concept of Coenosia sensu lato only includes the presence of two preapical setae in the third femur. Due to its wide distribution and species richness, a complete revision of Coenosia has never been accomplished. In contrast, there are several coexisting regionally focused taxonomic diagnoses of the genus, such as that of Huckett (1934a) for North American species, that of Sorokina (2009) for Siberian species, that of Couri and Pont (2016) for African species, and that of our research group (Patitucci et al. 2021) for southern South American species. In addition, diverse subgroups are used as subgenera in different regions such as the Nearctic region (Huckett and Vockeroth 1987) or the Neotropical region (Patitucci et al. 2021) or as species-group in the Oriental region (Xue and Wang 2014) or the Palearctic region (Hennig 1961).
Regarding Neodexiopsis, the other genus in which the species of Austrocoenosia were placed, its external morphology is very similar to that of Coenosia. The generic concept of Neodexiopsis only includes the presence of three preapical setae in the third femur. The genus is restricted to the New World, with a large proportion of the species (87 of the 96 described) distributed in the Neotropical region , many of which were described on the basis of female specimens. Although several taxonomic studies on this genus have been carried out (Snyder 1957(Snyder , 1958Couri and Albuquerque 1979;Costacurta et al. 2005;Patitucci and Couri 2018), more comprehensive studies of Neodexiopsis are needed.
From the phylogenetic point of view, Hennig (1965) suggested that Coenosia could be a non-monophyletic group, whereas Couri and Pont (2000) in their study of the phylogenetic relationships of Coenosiini based on morphological characters did not find synapomorphy characters for Coenosia or Neodexiopsis. More recently, based on morphological characters of Coenosiini from the Mexican Transition Zone, Gomes et al. (2020) obtained the same result.
As part of a series of studies based on extensive exploration of the Muscidae inhabiting the southern extreme of South America, we have collected new material, revised all the species placed by Malloch (1934) under Austrocoenosia, and discovered two new morphospecies that share the characters defined for the last genus. Thus, the main aims of this study were: 1) to assess the position of the species belonging to the genus Austrocoenosia proposed by Malloch (1934) with respect to the genera Coenosia and Neodexiopsis, by developing a hypothesis of phylogenetic relationships among the species of these genera by means of a cladistics analysis, using morphological and genitalia characters of female and male adults of the species; 2) to assess whether Austrocoenosia is a monophyletic group as proposed by Malloch (1934) or whether it is tional Museum of Natural History, Washington D.C., USA, BMNH -Natural History Museum, London, United Kingdom, UMO -Oxford University Museum of Natural History, United Kingdom, and ZMUH -Universität von Hamburg, Zoo logisches Institut und Zoologisches Museum, Hamburg.
The labels of the type specimens examined are cited verbatim, lines separated by a slash, different labels by semicolon, and comments are given in brackets.

Taxonomic work
All known synonyms for each species, as well as a list of generic combinations for the currently valid names are provided.
Species distributions are based on examined material and published records. Countries and localities for specimens examined are given in full.
Images, measurements, and maps. Digital photographs were taken using an Olympus DP 25 digital camera mounted on an Olympus SZX 16 stereomicroscope, and a Touptek TC digital camera mounted on a Lancet XSZ-146AT microscope. Images were processed using the Olympus cellSens Standard software and Combine ZM (Alan Hadley, UK).
Scanning Electron Microscopy (SEM) images were taken with a Philips XL30 TMP scanning electron microscopeat the MACN. The structures used were dehydrated through 80, 90, and 99.5% ethanol, and coated with gold-palladium in a Thermo VG Scientific SC 7620 sputter coater. Measurements of the body length (considered as the lenght between the anterior margin of the head (frons), excluding antenna, to the apex of the abdomen) were digitally obtained with the software Leica Application Suite EZ Version 2.1.0. Distribution maps were created with the QGIS software 2.18.3 (http://www. qgis.org/pl/site) and edited with Adobe Illustrator CS6. The shapefiles used are available at 'Instituto Geográfico Nacional de Argentina' (http://www.ign.gob.ar), 'Áreas Naturales Protegidas de Neuquén' (https://www.anp. gob.ar), 'Administración Parques Nacionales' (https:// mapas.parquesnacionales.gob.ar), and Romano (2017). The biogeographic regionalization scheme used was that proposed by Morrone (2014Morrone ( , 2015. To facilitate the use of georeferenced biodiversity data, a geospatial table is presented with the new records produced in this study (Table S3).

Phylogenetic work
Taxon sampling. The terminal taxa studied are 36 species representative of the genera Coenosia and Neodexiopsis. These included 29 valid Coenosia species: five previously included in Austrocoenosia, eight from the Andean biogeographic region, 15 representing the largest possible number of species-groups and geographical regions of the world, and Coenosia tigrina (Fabricius, 1775), the type species of Coenosia, and seven valid Neodexiopsis species: three previously considered in the genus Austro coenosia, two belonging to the Neodexiopsis "ovata group", and Neodexiopsis rufipes (Macquart, 1851), the type species of Neodexiopsis. The outgroup taxa Helina australis Pont in Carvalho et al. 1993, Lispoides inaequifrons Malloch, 1934, Reynoldsia rufoapi cata Malloch, 1934, andSpathipheromyia guttipennis (Thomson, 1868) were chosen based on the phylogenetic hypothesis of the Coenosinii presented by Couri and Pont (2000). All the species included in the analysis and their geographical distributions are listed in Table 1.

Characters and character states
A total of 132 characters from the male and female adults were coded. These were discrete characters, and included: from males: the head and its appendages (0-16), the thorax (17-38), the wings and halteres (39-40), the abdomen (41-53), the legs (54-75), and the terminalia (76-103), and from females: the head, thorax, wings, abdomen, legs and ovipositor (104-131). Characters used by Couri and Pont (2000) are highlighted with (*), and those modified from Couri and Pont (2000) are highlighted with (**). The distribution of character states in the terminal taxa is indicated in the data matrix in Table S1.

Phylogenetic analysis
Characters were treated as unordered and non-applicable characters were coded as '-', whereas unknown character states were coded as '?' (Strong and Lipscomb 1999). The program TNT 1.0 (Goloboff et al. 2003) was used to search for optimal trees using implied weights with a weighting strength of K= 3. The high presence of parallelisms and reversals in previous cladistics studies on different taxa of Muscoidea (Couri and Pont 2000;Roig-Juñent 2008, 2017), suggests that the value of K chosen for the analysis (K = 3) ponders the weight of the characters with a high homoplasy, favoring the characters with greater fit. Heuristic, unconstrained searches for optimal trees were conducted using tree bisection reconnection (TBR) branch swapping in each of 1000 replications of random taxon addition sequences, maintaining up to 10 trees per replication. A second TBR round was applied to each of the optimal trees, to increase confidence of finding all minimum-length topologies. Zero length branches were collapsed and strict consensus trees were generated. The support of groups was estimated using Bremer values, both absolute (Bremer 1994) and relative (Goloboff and Farris 2001), as well as symmetric resampling using 500 replicates (P = 0.33) (Goloboff et al. 2003). Bremer supports were calculated by obtaining suboptimal trees in 10 successive stages, saving up to 2000 sub-optimals at each stage. At every stage, we searched for suboptimal trees with 0.1 units of fit longer than the optimal tree. Since the fit is a concave function of homoplasy (Goloboff 1993), this means that we searched for trees with 0.1 to 1 units of fit longer than the optimal tree. Finally, as recommended by Goloboff and Farris (2001), relative support values were calculated by considering only the trees within the absolute Bremer support for each group.
Values of group support are indicated at each node. Characters in the text are referred with numbers followed a dash and the numbers of the states (e.g., 28-2). Some groups of species are named as "grades" when they form paraphyletic assemblages on the phylogenetic tree and "clades" when they form monophyletic groups (Fig. 5). This was done to facilitate the description and discussion of our results, but these groupings do not constitute a new classification (Buenaventura and Pape 2017).

Phylogenetic results
Searches under implied weights yielded one optimal tree, with a fit of 60.46898 (Fig. 5). Neither of the two valid genera herein studied, Coenosia and Neodexiopsis, were recovered as monophyletic. Species previously ascribed to Austrocoenosia under the original concept of Malloch (1934) were not recovered as a monophyletic genus, but formed an apical monophyletic clade (except C. aurifera) (node 53), within Coenosia. The three also shows that Lispoides inaequifrons was placed as the sister taxon to all other Coenosiini, with Coenosia spumicola at its base, followed by Spathipheromyia guttipennis and Reynoldsia rufoapicata (Fig. 5).
Clade 47 included all Coenosia and Neodexiopsis species (except C. spumicola), and was supported by nine apomorphies, four of which are exclusive (Table S2). The species of Neodexiopsis were grouped in a clade (node 46) with two species of Coenosia from the Neotropical region and with C. wulpi from the Mexican transition zone (here referred to as Neodexiopsis grade (Fig. 5)), supported as a monophyletic group by the character states 85-1 and 114-2 (Table S2).
Coenosia reidbergi was placed as the sister taxon to two geographically distinct groups: the first clade (node 73, Fig. 5) grouped six species of Coenosia distributed in Figure 5. Tree obtained with implied weights (k = 3). Absolute, relative Bremer supports and Symmetric resampling values indicated below each node. Species originally described by Malloch (1934) as part of Austrocoenosia genus -scientific names in red. Neodexiopsis grade -green branches; Coenosia chaetosa group -brown branches; Coenosia aurifera group -yellow branches; and Coenosia argentifrons group -blue branches. Synapomorphies: black circles, homoplasies: empty circles.
the Palearctic, Ethiopian, and Nearctic regions, and a single Neotropical species (C. setiventris), whereas the second clade (node 53, Fig. 5) grouped 12 species of Coenosia endemic to the Andean region, including all species previously ascribed to Austrocoenosia under Malloch's original concept.
The results of the present study show that many of the characters are highly homoplasious (Table 2), and that support measures were generally low, with few exceptions (Fig. 5). The use of implied weights reduced the possibility of groupings based on strongly homoplasious characters, such as leg chaetotaxy of male and female external morphology, because they were down-weighted during the process.
For lists of character changes, for all nodes, see Table  S2.
Diagnosis of the Coenosia aurifera group. The Coenosia aurifera group is defined by the combination of the following characters: grey species, with grey or brownish-yellow pollinosity [except head of males of C. aurifera with golden pollinosity]; frons longer than wide; dorsocentrals 1+3, with an eaDC, that is usually less than one third or fifth of length of the aDC [except C. delneneo sp. nov., with eaDC is half (or more) of length of aDC]; mid tibia with one ad and one pd median setae; hind femur with one preapical ad and one pd [dorsal in some specimens of C. aurifera] setae; hind tibia with one long ad seta and one fine av setae, a pd seta with variable length. Males can be characterized by tergite 6 and epadrium visible on dorsal view, and cercus longer than broad with strong spines. Female ovipositor presents tergite 6 with four plates. The Coenosia aurifera group here proposed includes C. aurifera, C. delneneo sp. nov., and C. tarsata. This group seems to be biogeographically circumscribed to the Andean chains, especially to the Subantarctic sub-region and the south extreme of the Andean sub-regions.

Descriptions.
To avoid lengthy and redundant descriptions, the characters listed below are present in all species of C. aurifera group. -Male. Head: Dichoptic; eyes bare. 3-4 pairs of frontal setae, 1 pair of reclinate orbital setae. Frons longer than wide, frontal triangle not visible, with the same color of the frons [except female of C. aurifera with a visible triangle] (Fig. 7B). Inner vertical setae strong and longer than outer vertical setae. Ocellar  setae strong and long. Occiput with three rows of setae: a posterior row at dorsal middle of head, a central row complete, and an anterior row at ventral middle of head. Gena with black hairs, and with height greater than the width of the postpedicel. Antenna inserted at the mid-level of the eye in lateral view. Palpus filiform. Thorax: Without vitta; anterior and posterior spiracles grey. Chaetotaxy: intra-alars 1+2, posterior postsutural seta shorter; supra-alars 1+1; postpronotals 2; notopleurals 2. Prealar absent. Scutellum with one long basal and one long apical pair of setae, similar in size: katepisternals 1+1+1, forming an equilateral triangle; anepimeron, katepimeron, and meron bare, proepisternals 2; proepimeral 2, lower seta downcurved. Prosternum bare. Wing: Hyaline; veins bare, except costal vein; lower calypter glossiform, twice longer than the upper one. Tegula yellow. Halter yellow. Legs: Fore tibia with one median posterior seta. Mid femur with 2 preapical setae on pd to posterior surface. Hind femur with one preapical ad setae and one pd (dorsal in some C. aurifera specimens) setae. Hind tibia with one long ad seta, a long pd seta, and one shorter av setae. Similar sized claws and pulvilli of the three legs. Abdomen: Tergite 6 visible in dorsal and lateral view. Epandrium globose, wider than tergite 6 in dorsal view. Sternite 1 bare. Sternite 5 longer than broad with basal margin convex. Terminalia: Cercus longer than broad, sclerotized, with strong spine, and apical margin concave with 2 teeth strongly sclerotized. Surstyli longer than broad, straight, and curved at tip. Hypandrium tubular longer than wide, distal extreme exposing the phapod. Aedeagus with phapod straight, strongly sclerotized, and longer than hypd in lateral view; pregt developed, kidney-shaped, ventrally fused with the hypd; pgt developed, epiphalus slightly sclerotized, and distiph tubular, with a sclerotized ring at base and extending on dorsal surface to tip, and with a brush of fine hair on ventral surface. -Female. Ovipositor: Tergites 6 with two long and wide sclerotized plates and two square plates, epiproct with "boomerang" shape, with hair-like setae, shorter than cercus; hypoproct triangular, setulose, with several strong setae on distal margin.

Coenosia aurifera (Malloch, 1934)
Male (Fig. 6A). Length. Body: 3.56-3.70 mm, wing: 2.89-3.02 mm. Head (Fig. 6B): Frons at vertex about one third of the head width. Frons, fronto-orbital plate, parafacial and gena yellow with golden pollinosity. Fronto-orbital plate without setulae, close to parafacialia. Antenna light brown with yellow pollinosity; arista brown with its longest microtrichia shorter than its basal diameter. Palpus yellow. Thorax: (Fig. 6C). Grey with light brown pollinosity. Chaetotaxy: acr s strong and biseriate; anterior presutural acr s longer than the eaDC; dorsocentrals 1+3, eaDC is less than one fifth of the aDC. Anepisternum with a series of 4-5 strong setae; katepisternum with 1-2 setula. Wing: Both calypters whitish hyaline with white margins. Legs: Coxae and femora grey. Trochanters, apex of femora, tibiae, and tarsus yellow. Fore femur with a row of strong pd setae, and a row of strong pv setae. Mid femur with 2 strong setae on ventral surface, and 2-3 setae on anterior surface; mid tibia with one ad and one pd median setae, both setae with the same length and position. Hind femur with a row of ad and a row of av setae, and two long setae on ventral surface, with two preapical setae (ad and dorsal); hind tibia with 4 preapical setae (ad, dorsal, pd, ventral). Abdomen: (Fig. 6D, E). Grey with brown spots on tergites 3-5. Sternite 5 with apical margin with a thin "U" shape and without membrane; setae concentrated on the lobes and some long and strong on apical margin (Fig. 6F). Terminalia: Cercus with strong spine on apical third ( Fig. 6G-I).
Remarks. Coenosia aurifera was described with male and female specimens by Malloch (1934) as part of the genus Austrocoenosia. This author highlighted its striking coloration and the unique shape of the male abdomen.
Our observation also showed morphological (male abdomen, cercus, and female ovipositor) and phylogenetic evidence to distinguish this species from the remaining species of Austrocoenosia presented by Malloch.

Coenosia delneneo sp. nov.
h t t p s : / / z o o b a n k . o rg / 1 8 6 3 B 9 FA -0 9 7 C -4 4 6 5 -9 2 8 9 -DE7B93737D43 Male (Fig. 8A). Length. Body: 5.56-5.90 mm, wing: 4.1-4.69 mm. Head: (Fig. 8B). Frons at vertex about one third of the head width. Frons, fronto-orbital plate, parafacial and gena black with yellow-grey pollinosity. Fronto-orbital plate with 1-3 little setulae, close to parafacialia. Antenna dark brown, apex of pedicel with yellow pollinosity; arista brown with its longest microtrichia hardly longer than its basal diameter. Palpus black. Thorax: (Fig. 8C). Grey with light brown pollinosity. Chaetotaxy: acr s strong and biseriate; anterior presutural acr s shorter than the eaDC; dorsocentrals 1+3, eaDC is half (or more) of length of the aDC. Anepisternum with a series of 4-5 strong setae; katepisternum with 2-3 setula. Wing: Both calypters whitish hyaline with white margins. Legs: Coxae grey. Fore femur yellow with a black large spot on dorsal to posterior surface. Trochanters, femora, tibiae, and 1-4 tarsomeres yellow. Fifth tarsomere black. Fore femur with a row of strong pd setae, and a row of strong pv setae. Mid femur with a row of strong setae on ventral surface, and 5-6 setae on anterior surface; mid tibia with one ad and one pd median setae with the same length, ad seta positioned below of the pd seta. Hind femur with a complete row of ad and a complete row of av setae, two setae on anterior surface at middle, and a row of setae on ventral surface, hind tibia with 3 preapical setae (ad, dorsal, ventral). Abdomen: (Fig. 8D). Grey without spots, tergite 6 and epand brighter than the other tergites. Sternite 5 with apical margin concave ("U" shape) and membrane; setae concentrated on the lobes and some long and strong on apical margin (Fig. 8E). Terminalia: Cercus with strong spines on apical middle (Fig. 8F, G).
Female (Fig. 9A, B). Length. Body: 5.70-6.00 mm, wing: 4.8-5.12 mm. Differs from male as follows: Legs: Mid tibia with one ad and one pd median setae, both setae with the same length and position. Ovipositor: Segments longer than wide. Tergites 7 and 8 with two long and wide sclerotized plates (Fig. 9C). Sternites 6 and 7 with one short and thin plates; sternite 8 divided into two small and sclerotized plates each with 4-5 setae on distal margin (Fig. 9D). Three spermathecae, oval shaped, with a small prominence at the opposite end of the insertion of the tracheola (Fig. 9E, F). Distribution (Fig. 12B). ARGENTINA: Neuquén, Río Negro.
Etymology. The name "delneneo" refers to an expression in Spanish to the vulgar name (neneo) of the plant Mulinum spinosum Pers., where several specimens were collected.
Remarks. Coenosia delneneo sp. nov. is distinguished from its congeners by the following combination of characters: gena height greater than the width of the postpedicel, thorax and abdomen gray without vitta or spots, fore femur yellow with a black large spot on dorsal to posterior surface, fifth tarsomere black, dorsocentrals 1+3, with an extra short presutural pair which is half (or more) of the length of the presutural seta, hind tibia with one long ad seta, a long pd seta, and one fine av setae, and cercus longer than broad and with strong spines. Male: tergite 6 and epandrium visible and brighter, distiph with a brush of fine hair on ventral surface. Female: ovipositor in tergites 6 with two long and wide sclerotized plates and two square strongly sclerotized plates, and epiproct with "boomerang" shape. In Stein's key (1911), C. delneneo comes close to Coenosia pilitibia Stein 1911, but differs in the chaetotaxy of the mid tibia. In Malloch' key (1934), C. delneneo comes close to C. ignobilis Stein, 1911, but the coloration of the fore femur and the shape of the abdomen can separate it from the latter.
Remarks. Snyder (1957) described C. tarsata with one male and two female specimens from Santa Cruz prov-ince, Argentina. In his work (op. cit.), the author used the classification proposed by Huckett (1934a) and placed the species under the genus Limosia. Snyder (1957) found it difficult to use the generic diagnosis of Coenosia and Austrocoenosia proposed by Malloch (1934) for the species of Patagonia, because he could not establish the presence of the pd seta on the hind tibia. In Stein' key (1911), C. tarsata comes close to Coenosia pilitibia Stein 1911, but differs in the chaetotaxy of the mid tibia. In Malloch's key (1934), C. tarsata comes close to A. ignobilis (Stein, 1911), but the coloration of fore femur and the shape of the abdomen can separate both species.
Nomenclature note. Huckett (1965)   ilar length and width]; dorsocentrals 1+3, with an eaDC, that is usually less than one third or fifth of length of the aDC [except C. brevicornis with eaDC is half of length of aDC]; mid tibia with one ad and one pd median setae; hind femur with one preapical ad and one pd setae; hind tibia with one long ad seta and one fine av seta, a pd seta.
Male terminalia can be characterized by cercus longer than broad with two longitudinal keels. Female spermathecae, with erythrocyte shape. The Coenosia argentifrons group here proposed includes C. argentifrons, C. brevicornis, C. dubia, C. ignobi lis, C. inusitata, C. nigerrima, C. patagonica sp. nov., and C. projecta. This group includes all the species originally assembled by Malloch (1934) under the genus Austrocoenosia (with the exception of C. aurifera) and a new species. This group seems to be biogeographically circumscribed to the Andean chains, especially in to the Central Chilean and Subantarctic sub-regions of South America.

Coenosia brevicornis (Malloch, 1934) new comb.
Female. (Fig. 14A). Length. Body: 3.44 mm, wing: 3 mm. Head (Fig. 14B): Frons at vertex about one third of the head width. Frons black with brownish pollinosity; fronto-orbital plate, parafacial and gena black with grey pollinosity; 4 pairs of frontal setae. Frons longer than wide, with frontal triangle short, light grey, not reaching lunula. Gena with similar height to the width of the postpedicel. Antenna black, apex of pedicelum yellow, apical angle of postpedicel acute; in lateral view inserted at the mid-level of the eye; arista swollen at base, with his longest hairs hardly longer than its basal diameter. Thorax: (Fig. 14C). Black with grey pruinescent, with two brown vitta along dorsocentral setae and intra-alar setae; anterior and posterior spiracles grey. Chaetotaxy: acrostichals irregular; dorsocentrals 1+3, eaDC is half of length of the aDC. Katepisternum with 3 setulae. Wing: Tegula yellow. Both calypters hyaline with white margins; halter yellow. Legs: Fore femur black with yellow apex, mid and hind femora yellow with a black band at apical third, tibiae yellow, tarsus black. Fore femur with a row of dorsal, posterior, pv, and an av row at basal half. Mid femur with 5-6 setae on anterior surface on basal half, 2-3 pv and 2-3 av setae on basal third, 2 preapical setae on pd to posterior surface; mid tibia with one long ad seta and one short pd median seta, ad seta positioned below of the pd seta. Hind femur with a row of ad and a row of av setae, 3 pv setae on basal third. Similar size of claws and pulvilli of the three legs. Abdomen: Grey, tergites 3-4 with two brown spots and tergites 3-5 with a thin central longitudinal stripe. Ovipositor: Tergites 6 and 7 with two parallel sclerotized plates, tergite 8 with two short and round sclerotized plates over distal margin; epiproct triangular, with hair-like setae, shorter than cercus ( Fig. 14D). Sternites 6 and 7 with one central sclerite; sternite 8 divided into two small and linear sclerotized plates, each with setulae on distal margin; hypoproct triangular, setulose (Fig. 14E). Spermathecae (Fig. 14F) Fig. 27D). ARGENTINA: Chubut (new record). CHILE: R. de los Lagos. Malloch (1934) with a single male specimen from Ancud, Chile. Some structures, such as one eaDC with half the length of the aDC, the coloration of the legs, and the profile of the head, allow distinguishing C. brevicornis from its congeners. After the original publication, a new combination, Neodexiopsis brevicornis, was established by Pont (1972). During our sampling campaigns, we collected only one female specimen with the same characters that distinguish C. brevicornis from its congeners and that are consistent with the general morphology of the male holotype. In addition, the female specimen possesses an erythrocyte-shape spermatheca, similar to that observed in all species of the C. argentifrons group. We propose the new combination.

Coenosia dubia (Bigot, 1885) comb. rest.
Male (Fig. 15A). Length. Body: 3.98-4.22 mm, wing: 3.70-4.00 mm. Head: (Fig. 15B). Frons at vertex about one third of the head width. Frons, fronto-orbital plate, parafacial and gena black with silver-grey pollinosity; 3-4 pairs of frontal setae. Frons longer than wide, with frontal triangle long, light grey, reaching lunula. Gena higher than the width of postpedicel. Fronto-orbital plate with 3-5 little setulae, close to parafacialia. Antenna black, apical angle of postpedicel acute; in lateral view inserted at the mid-level of the eye; arista with its longest microtrichia with similar length than its basal diameter. Thorax: (Fig. 15C). Black with grey pollinosity, with three fine dark-brown vitta along acrostichal and dorsocentral rows of setae; anterior and posterior spiracles grey. Chaetotaxy: acr s short and strong, the anterior presutural pair shortest as the anterior presutural dorsocentral seta; dorsocentrals 1+3, eaDC is less than one third of the aDC. Katepisternum with 2-3 setulae. Wing: Tegula black. Both calypters whitish hyaline with white margins; halter yellow. Legs: Black with grey pollinosity, apex of femora yellow. Fore femur with a row of strong pd, a row of strong pv setae, and a row of av setae at basal third. Mid femur with a row of fine ventral setae, 3-4 strong setae on anterior surface, and 2 preapical setae on pd to posterior surface; mid tibia with one ad and one pd median setae, both setae with the same length and position. Hind femur with ad and av rows of setae. Fore claws and pulvilli longer than mid and hind pairs. Abdomen: (Fig. 15D). Grey with sub-triangular lateral dark-brown marks on tergites 1+2-5 (more evident on 3-5). Tergite 6 poorly visible in dorsal view. Sternite 5 broader than long, apical margin concave, with a depressed area at the base, and without membrane; setae concentrated on the lobes and some long and strong on apical margin (Fig. 15E). Terminalia: Cercus curved in lateral view, keels placed from distal to apical margin, wider at the base and thinner before apical tip, apical margin straight. Surstylus longer than broad, straight, barely sclerotized (Fig. 15F, G). Hypandrium tubular, wider than long, distal extreme exposing the phapod. Aedeagus with pregt developed barely sclerotized; pgt developed; epiphalus slightly sclerotized, and distiph tubular, slightly sclerotized at base, and without fine hair on ventral surface (Fig. 15G, H). Female (Fig. 16A, B). Length. Body: 4.4-4.7 mm, wing: 4.10-4.33 mm. Differs from male as follows: Thorax: (Fig. 16C). Black with grey pollinosity, with five fine dark-brown vitta along acrostichal, dorsocentral and intralars rows of setae; Ovipositor: Tergites 6, 7, and 8 with two long and wide sclerotized plates; epiproct triangular, with spine-like setae, shorter than cercus (Fig. 16E). Sternites 6 and 7 with one long and wide plate; sternite 8 with one central plate and two small and sclerotized plates each with 4-5 setae on distal margin; hypoproct triangular, setulose, with several strong setae on distal margin (Fig. 16F). Spermathecae (Fig. 16G).
Type material. The type specimen is housed in Oxford University Museum of Natural History (UMO), United Kingdom. https://oumnh.ox-.ac.uk/collections-online#/item/oum-catalogue-381555. Pont (2000:11) observed that the holotype is in very poor condition "…head, abdomen, right fore leg, right mid leg, and both hind legs missing…", and suggested that this species was correctly recognized by Malloch (1934: 218). Remarks. Bigot (1885) described Anthomyia dubia with only one female specimen from an unspecified location of Chile. Later, Stein (1907) observed this specimen and proposed a synonym with Coenosia mediocris Stein (1919). After that, Malloch (1934) recognized dubia with a large series of male and female specimens from Argentina and Chile, presented a very brief description, and considered it as part of Austrocoenosia. Later, Couri and Albuquer- que (1979) included the species as part of the genus Neodexiopsis, establishing the current name. Then, Pont (2000Pont ( , 2001 established that mediocris Stein and dubia Bigot are two different species, and later (Pont 2012) resolved a possible homonymy with the species Caenosia dubia Macquart, 1835. Recently, Couri and Pont (2020) presented a good redescription of the type specimens of C. mediocris. In the present study, we compared with our specimens of C. dubia and found several differences, including the coloration and the hind tibia chaetotaxy. We also found morphological and phylogenetic evidence to consider C. dubia as part of the C. argentifrons group, and revalidated the combination Coenosia dubia.

Coenosia ignobilis Stein, 1911
Male (Fig. 17A). Length. Body: 3.05-3.27 mm, wing: 3.00-3.10 mm. Head: (Fig. 17B). Frons at vertex about one third of the head width. Frons, fronto-orbital plate, parafacial and gena dark brown with grey pollinosity; 3-4 pairs of frontal setae. Frons longer than wide, with frontal triangle long, light grey, reaching lunula. Gena height less than the width of postpedicel. Fronto-orbital plate with 3-5 little setulae, close to parafacialia. Antenna black, apical angle of postpedicel acute; in lateral view inserted at the mid-level of the eye; arista with its longest microtrichia with similar length than its basal diameter. Thorax: (Fig. 17C). Black with grey pollinosity, with a dark-brown vitta along acrosticals setae and a vitta between dorsocentral and intra-alar rows of setae; anterior and posterior spiracles grey. Chaetotaxy: acr s short and irregular, the anterior presutural acr s with similar length to the eaDC; dorsocentrals 1+3, eaDC is less than one third of the aDC. Katepisternum with 2-3 setulae. Wing: Tegula black. Both calypters whitish hyaline with white margins; halter yellow. Legs: Black, apex of fore femur, basal half of mid and hind femora, and tibiae yellow; tarsus black. Fore femur with a row of strong pd, a row of strong pv setae, and a row of av setae at basal third. Mid femur with 5-6 setae on anterior surface on basal half, 2-3 pv and 2-3 av setae on basal third, 2 preapical setae on pd to posterior surface; mid tibia with one ad and one pd median setae, ad seta longer and placed more apically than pd seta. Hind femur with a complete row of ad and a row of av setae on apical half, with three pv seta on basal third, apical most is the longest of the three. Similar size of claws and pulvilli of the three legs. Abdomen: (Fig.  17D). Black, with grey pruinosity, tergites 3-5 with two dark brown spots. Tergite 6 partly visible in dorsal view. Sternite 5 broader than long, apical margin concave with a "U" shape, and with membrane; setae concentrated on the lobes and some long and strong on apical margin (Fig.  17E). Terminalia: Cercus curved in lateral view, keels only on basal two-thirds, apical margin straight (Fig. 17F, G). Surstylus longer than broad, wide at base and tapering towards apex, straight, sclerotized (Fig. 17H). Hypandrium tubular, wider than long, distal extreme exposing the phapod, and with several hairs on ventral surface. Aedeagus with pregt developed and sclerotized; pgt developed; epiphalus slightly sclerotized, and distiph tubular, sclerotized at base, and with spines on lateral surface (Fig.  17G, I-J).
Female (Fig. 18A, B). Length. Body: 3.70-4.40 mm, wing: 3.50-4.24 mm. Differs from male as follows: Legs: Mid and hind femora more yellow, hind tibia with one long ad, one short av, and one long pd setae on middle third. Ovipositor: Tergites 6, 7, and 8 with two long and wide sclerotized plates; epiproct triangular, with hair-like setae, shorter than cercus (Fig. 18C). Sternites 6 and 7 with one long and wide plate; sternite 8 with one central plate and two small, linear, and sclerotized plates each with 4-5 setae on distal margin; hypoproct triangular, setulose, with several strong setae on distal margin (Fig.  18D). Spermathecae (Fig. 18E). Remarks. Stein (1911) described Coenosia ignobilis with male and female specimens from Chile. Later, Malloch (1934) studied a large series of male and female specimens from Argentina and Chile, presented a brief description, and considered it as part of Austrocoenosia. Later, Couri and Albuquerque (1979) observed a female specimen from the series of specimens studied by Malloch (op. cit), and included the species as part of the genus Neodexiopsis. Pont (2001) designated lectotypes and paralectotypes and established the original combination Coenosia ignobilis. Recently, Couri and Pont (2020) presented a redescription of the paralectotype housed in ZMUH. (Malloch, 1934) Male (Fig. 19A). Length. Body: 4.43-4.8 mm, wing: 4.05-4.24 mm. Head: (Fig. 19B). Frons at vertex about one third of the head width. Frons, fronto-orbital plate, parafacial and gena black with grey pollinosity; 4-5 pairs of frontal setae. Frons longer than wide, with frontal triangle long, light grey, reaching lunula. Gena higher than the width of postpedicel. Fronto-orbital plate with 1-3 setula, close to parafacialia. Antenna black, apical angle of postpedicel acute; in lateral view inserted over the mid-level of the eye; arista with its longest microtrichia shorter than its basal diameter. Thorax: (Fig. 19C). Black with grey pollinosity, with three black vitta at dorsocentral and acrosticals rows of setae; anterior and posterior spiracles grey. Chaetotaxy: acr s short and irregular, the anterior presutural acr s longer than the anterior presutural dorsocentral seta (eaDC); dorsocentrals 1+3, eaDC is less than one third of the aDC. Katepisternum with 2-3 setulae. Wing: Tegula black. Both calypters whitish hya-line with white margins; halter yellow. Legs: Black with grey pollinosity, apex of femora yellow. Fore femur with a row of strong pd, a row of strong pv setae, and a row of av setae at basal third. Mid femur with 5-6 setae on anterior surface on basal half, 2 long setae on ventral surface, 2 preapical setae on pd to posterior surface; mid tibia with one ad and one pd setae on median third, ad seta shorter and positioned below pd seta. Hind femur with a complete row of ad setae and a row of anterior setae which are positioned in dorsalventral direction (Fig. 19E), with 1-2 pv seta on basal third. Similar size of claws and pulvilli of the three legs. Abdomen: (Fig. 19D). Black, with grey pruinosity, tergites 3-5 with two dark brown spots. Tergite 6 not visible in dorsal view. Sternite 5 broader than long, apical margin strong concave, with a depressed area at the base, and without membrane; setae concentrated on the lobes and some long and strong on apical margin (Fig. 19F). Terminalia: Cercus curved in lateral view, keels only on basal half, apical margin straight. Surstylus longer than broad, curved at apex, sclerotized (Fig. 19G, H). Hypandrium tubular, wider than long, distal extreme not exposing the phapod. Aedeagus with pregt developed sclerotized; pgt developed; epiphalus sclerotized, and distiph tubular, sclerotized at base, and without spine on ventral surface (Fig. 19H, I).

Distribution (
Remarks. Coenosia inusitata was described by Malloch (1934) with male and female specimens from Angol, Chile. Specimens captured by LDP and PRM were collected in open areas (steppe), close to rivers. The abdomen of only female specimen collected was photographed and then removed for the dissection of the terminalia. (Malloch, 1934) comb. rest. Male (Fig. 21A). Length. Body: 3.40-3.94 mm, wing: 2.80-3.49 mm. Head: (Fig. 21B). Frons, fronto-orbital plate, parafacial and gena black. 5-6 pairs of frontal setae. Frons at vertex about one third of the head width. Frons with similar length and width, with frontal triangle short, black, not reaching lunule. Gena with a similar width to the postpedicel. Fronto-orbital plate with 6-8 short setulae, close to parafacialia. Parafacial in lateral view narrow. Antenna black; in lateral view inserted over the mid-level of the eye; arista with its longest microtrichia shorter than its basal diameter. Palpus black. Thorax: (Fig. 21C). Black with brown pollinosity, without vitta; anterior and posterior spiracles black. Chaetotaxy: acr s strong and biseriate; anterior presutural pair lon- ger than the extra pair of presutural dorsocentral (eaDC); dorsocentrals 1+3, eaDC is less than one fifth of the aDC. Katepisternum with 2-3 setulae. Wing: Tegula black. Both calypters hyaline with black margins; halter black. Legs: Coxae, trochanters, femora, tibiae, and tarsus black. Fore femur with a row of strong pd to pv setae, and a row of strong av setae on basal third. Mid femur with 1-2 long setae on ventral surface, a row of setae on anterior surface, and 2 preapical setae on pd to posterior surface; mid tibia with one ad and one pd median setae, with the same length and ad seta positioned below pd seta. Hind femur with a row of ad and a row of av setae, with one preapical ad seta and one pd seta. Hind tibia similar size of claws and pulvilli of the three legs. Abdomen: (Fig. 21D). Black without spots. Tergite 6 not visible in dorsal or lateral view. Sternite 5 broader than long, apical margin concave with a thin "U" shape reduced towards the base, and without membrane; few setae concentrated on the lobes and some long and strong on apical margin (Fig. 21E). Terminalia: Cercus curved in lateral view, and two longitudinal keels only on basal half, apical margin straight. Little spines on inner surface. Surstylus broad at base and at apex, curved, with a pointed process at apical third in inner surface (Fig.  21F-H). Hypandrium tubular longer than wide, with several little spicules close to pregt. Aedeagus with pgt developed and poor sclerotized; epiphalus slightly sclerotized, and distiph tubular, strongly sclerotized at base (Fig. 21I, J). Female (Fig. 22A, B). Length. Body: 3.75-4.10 mm, wing: 3.60-4.30 mm. Differs from male as follows: Wing: Both calypters hyaline with white margins. Ovipositor: Tergites 6, 7 and 8 with 2 long and wide scletotized plates; epiproct triangular, with hair-like setae, cercus longer than epiproct (Fig. 22C). Sternites 6 and 7 with long plates; sternite 8 with a central long plate and 2 small plates each with 4-5 setae on distal margin; hypoproct triangular, with several short setae on distal margin (Fig. 22D). Spermathecae (Fig. 22E). Remarks. Malloch (1934) described C. nigerrima with females and male specimens from Argentina and Chile, and proposed it as the type species of Austrocoenosia. Also, this author highlighted the dark black coloration and the absence of marks on the thorax and abdomen, characters that differentiate this species from the remaining Austrocoenosia species. Later, Pont (1972) transferred the species to Coenosia. After that, Couri and Albuquerque (1979) presented drawing of the female and male terminalia, and transferred the species to Neodexiopsis. The general black coloration, and the strongly sclerotized male terminalia make it difficult to correctly identify the species. In the specimens studied in the present work, we observed some differences (presence of keels on the cercus, shape of the surstylus) from the drawings presented by Couri and Albuquerque (1979). We found morphological and phylogenetic evidence to consider this species as part of the C. argentifrons group, and thus restored the previous combination proposed by Pont (1972) Coenosia nigerrima.

Coenosia nigerrima
Regarding its distribution, several authors (Costacurta et al. 2003;Rodríguez-Fernández et al. 2006;Krüger et al. 2010;Fogaça et al. 2020) recorded this species in the South of Brazil (Fig. 23B). Since species of the C. argentifrons group presents restricted distribution in the Central Chilean and Subantarctic subregions; it would be interesting to examine the specimens collected in southern Brazil to establish similarities and differences.
Both calypters whitish hyaline with white margins; halter yellow. Legs: Coxae grey. Fore femur grey with apical tip yellow, mid and hind femora yellow with a black apical ring or a dorsal band. Tibiae yellow. Tarsus black. Fore femur with a row of strong pd, a row of strong pv setae, and a row of av setae at basal third. Mid femur with 4-5 setae on anterior surface on basal half, 2-3 pv and 2-3 av setae on basal third, 2 preapical setae on pd to posterior surface; mid tibia with one ad and one pd median setae, with similar length, ad positioned below of the pd seta. Hind femur with a complete row of ad and a row of av setae, with 2-3 pv setae on basal third. Similar size of claws and pulvilli of the three legs. Abdomen: (Fig. 24D). Black, with grey pruinosity, tergites 1+2-5 with two dark brown spots. Tergite 6 not visible in dorsal. Sternite 5 broader than long, apical margin concave with a "U" shape, with a depressed area at the base, and without membrane; setae concentrated on the lobes and some long and strong on apical margin (Fig. 24E). Terminalia: Cercus curved in lateral view, keels present at basal half, apical margin little concave. Surstylus longer than broad, narrowing towards the apex, straight, sclerotized ( Fig. 24F-H). Hypandrium tubular, wider than long, with several spines on ventral surface. Aedeagus with pregt developed sclerotized; pgt developed; epiphalus long and not sclerotized, and distiph tubular, sclerotized at base, and without spine on ventral surface (Fig. 24H, I).
Female (Fig. 25A, B). Length. Body: 3.95-4.40 mm, wing: 3.55-4.10 mm. Differs from male as follows: Thorax: Chaetotaxy: acr s long and irregular, the anterior presutural pair longer than the anterior presutural dorsocentral seta. Katepisternum with 6-8 setula. Ovipositor: Tergites 6 and 7 with two long and thin sclerotized plates, tergite 8 with two long and wide sclerotized plates; epiproct triangular, with hair-like setae, shorter than cer- cus (Fig. 25C). Sternites 6 and 7 with one long and wide plate; sternite 8 with two small, linear, and sclerotized plates each with 4-5 setae on distal margin; hypoproct triangular, setulose, with several strong setae on distal margin (Fig. 25D). Spermathecae (Fig. 25E).  Remarks. Coenosia patagonica sp. nov. is distinguished from its congeners by the coloration of its legs and its chaetotaxy. In addition, the male cercus has keels present at the basal half and the apical margin little concave, and surstylus longer than broad, whereas the female ovipositor is in tergite 8 with two long and wide sclerotized plates. In Stein's key (1911), C. patagonica comes close to Coenosia rotundiventris Stein 1911, but differs in the coloration of legs. In Malloch's key (1934), C. patagonica comes close to C. ignobilis Stein, 1911, but the coloration of the hind femur and the male terminalia can separate it from the latter. Coenosia projecta (Malloch, 1934) Male (Fig. 26A). Length. Body: 2.80-3.04 mm, wing: 2.25-2.48 mm. Head: (Fig. 26B). Frons at vertex about one third of the head width. Frons, fronto-orbital plate, parafacial and gena black with grey pollinosity; 3-4 pairs of frontal setae. Frons longer than wide, with frontal triangle long, light grey, reaching lunula. Gena narrow, narrower than the width of postpedicel. Fronto-orbital plate with 3-5 little setulae, close to parafacialia. Antenna black, apical angle of postpedicel acute; in lateral view inserted over the mid-level of the eye; arista with its longest microtrichia shorter than its basal diameter. Thorax: (Fig. 26C). Black with grey pollinosity, with three black vitta at dorsocentral and acrostichal rows of setae; anterior and posterior spiracles brown. Chaetotaxy: acr s short and irregular, the anterior presutural acr s longer than the anterior presutural dorsocentral seta (eaDC); dorsocentrals 1+3, eaDC is less than one third of the aDC. Katepisternum with 3-4 setulae. Wing: Tegula black. Both calypters whitish hyaline with white margins; halter yellow. Legs: Black with grey pollinosity, apex of femora yellow. Fore femur with a row of strong pd, a row of strong pv setae, and a row of av setae at basal third. Mid femur with 5-6 setae on anterior surface on basal half, 3-5 pv setae on basal third and a row of av setae, 2 preapical setae on pd to posterior surface; mid tibia with one ad and one pd median setae, with similar length. ad seta placed apical than pd seta. Hind femur with a complete row of ad and a row of av setae on apical half, with 3-4 pv setae on basal third. Similar size of claws and pulvilli of the three legs. Abdomen: (Fig.  26D). Black, with grey pruinosity, tergites 3-5 with two dark brown spots. Tergite 6 not visible in dorsal view. Sternite 5 broader than long, apical margin concave with a "U" shape, with a depressed area at the base, and without membrane; setae concentrated on the lobes and some long and strong on apical margin (Fig. 26E). Terminalia: Cercus curved in lateral view, keels placed from distal to basal margin, apical margin straight. Surstylus longer than broad curved at apex, sclerotized (Fig. 26F, G). Hypandrium tubular, wider than long, distal extreme not exposing the phapod, and without spines on ventral surface. Aedeagus with pregt developed and sclerotized; pgt developed; epiphalus slightly sclerotized, and distiph tubular, sclerotized at base, and without hairs on ventral surface (Fig. 26G, H). Remarks. Coenosia projecta was described by Malloch (1934) with one male specimen from Río Negro, Argentina. Malloch (1934: 224 Fig 38b) illustrated some striking long and fine hairs on the ventral surface of the hind femur, but did not mention anything in the description. We did not observe these hairs in the images of the type specimen or in the specimens collected, so we assume that this was a mistake in the original drawing.

Discussion
Reconstructing a group characterized by a high number of species and widely distributed in nearly all terrestrial regions remains a severe challenge (Cerretti et al. 2014).
Our present analysis allowed providing phylogenetic data on the evolution of Coenosia and/or Neodexiopsis, which can be tested and supplemented with further studies. In fact, this analysis, which was based on extensive morphological external and genitalia data of female and male adults of a large subset of species, represents the first study performed to elucidate the numerous species of Coenosia and Neodexiopsis.
The tree obtained was fully resolved, and neither Coenosia nor Neodexiopsis were recovered as monophyletic units. The same was observed for the genus Austrocoenosia previously ascribed under Malloch's original concept.

Coenosia spumicola.
Coenosia is a large group of Muscidae with many interspecific differences which, according to Huckett and Vockeroth (1987), should be considered as a repository of species, i.e., many of its species have been transferred to or from other genera over the years. Pont (1973) suggested that the position of C. spumicola within Coenosia was not clear, and suggested that it could belong to the tribe Limnophorini, a conclusion based on the comparison of the external morphology of C. spumicola with that of species of Limnophorini, and their shared aquatic habitat. Pont (1973) described the presence of an eaDC seta as a striking structure compared to other Coenosia species, although this seta is also present in other Coenosiini (e.g., Reynoldsia spp., or some Coenosia species). Coenosia spumicola also differs substantially from other Coenosia species in the width of the frons, which are wider than long, a character state shared in this study with S. guttipennis. Couri and Pont (2000) established that this character state (7-1) is a synapomorphy of some Coenosiini genera (Schoenomyza, Schoenomyzina, Notoschoenomyza, and Spathipheromyia). Both the width of the frons and the association with an aquatic environment have been recently observed in Spathipheromyia spp. (Patitucci et al. 2019) and Notoschoenomyza sulfuriceps . Taking into account the results obtained in this study and the information regarding C. spumicola, this species could be an example of why Coenosia has been considered a repository of species. We agree with Pont (1973) and Couri and Pont (2000) that this species does not belong to Coenosia and should be assigned to another genus. Thus, we currently consider C. spumicola as an unplaced species, and further studies are needed to resolve its phylogenetic position.
Neodexiopsis + Coenosia (clade 47). Although Coenosia and Neodexiopsis are at present considered as indepen-dent taxonomic entities, the position of these genera has been discussed by several authors. Huckett (1934a) was the first to modify their status as genera by considering that Coenosia sensu stricto, Hoplogaster, Limosia and Neodexiopsis were subgenera within Coenosia. However, the characters used by Huckett (1934b) to define Coenosia sensu lato were not very informative and, in a later study (Huckett and Vockeroth 1987), this subgeneric classification was disregarded. Later, in a phylogenetic analysis of the Coenosiini performed by Couri and Pont (2000), the relationship of Coenosia and Neodexiopsis with the other genera of the tribe could not be clarified, and these genera were thus in a large polytomy along with other genera, such as Bithoracochaeta, Stomopogon, Plumispina, etc. More recently, in a phylogenetic analysis that aimed to evaluate the position of a new genus of Coenosinii from the Mexican transition zone, Gomes et al. (2020) did not recover any synapomorphic characters for Coenosia or Neodexiopsis. Their results also showed that the species of Coenosia that they had included in their study were polyphyletic, whereas the species of Neodexiopsis formed a monophyletic unit.
Although it was not a primary goal of this study to examine the relationship between Coenosia and Neodexiopsis, clade 47 included all species of both genera (except for C. spumicola) and four of the synapomorphies supporting this clade (28-0, 29-1, 59-1, and 116-2) (Table  S2) are characters, previously observed by other authors. Characters 28 and 29 which have been recently re-interpreted, describe the shape of the eaDC (Patitucci et al. 2021). In this study, we considered the following: that the pDC (which is placed in a posterior position with respect to the middle line of the prescutum) has been lost or is at least reduced in Coenosinii, that the aDC has been conserved, and that the eaDC has been added. The presence of the eaDC has been considered and analyzed under different criteria within Coenosiinae: Malloch (1934) compared its width with that of acr s, Snyder (1957) mentioned these setae as "accessory presut dc setulae", and Gregor et al. (2002) and Sorokina (2009) compared the aeDC with the aDC. Couri and Pont (2000) analyzed this character considering the number of full sized (i.e., fully developed) setae (considering not full-sized setae as setulae), and hypothestized that the presence of two presutural DC setae was the plesiomorphic state or groundplan for Muscidae, with a reduction to one seta (without specifying which one) in Coenosinii. These authors also observed several reversals for this character in different branches of their tree. Due to the small size of this seta in most of the species included in our analysis (28-0: width of the eaDC similar to that of the presutural AC; 29-1: length of the eaDC 1/3 or less x length of the aDC), it could be interpreted that the eaDC is a setula and not a developed seta. Since the presence and location of the eaDC are constant in all species included in this study, even in species such as in R. rufoapicata and C. delneneo sp. nov. in which the eaDC is 1/2 or more of the length of the aDC, we consider it a developed seta and not a setula.
The two remaining synapomorphies of clade 47 (Fig.  5) are: in males, the presence of a single ad in the middle third of the hind tibia (59-1), and, in females, a single pd in the middle third of the mid tibia (116-2). Both characters states (59-1 and 116-2) are found in all species of Coenosia and Neodexiopsis included herein, with the exception of the species of Coenosia from the Australasian region (Table 1 and Table S2). Couri and Pont (2000) also observed a reduction in the number of setae on the pd surface of the mid tibia in all Coenosiini, with reversals in some genera of Coenosinii (e.g.: Spathipheromyia, Reynoldsia). Although these character states are not very informative at a generic level within Coenosiini, they could be more informative in studies at species level, as was observed by Nihei and Carvalho (2007), in a phylogenetic analysis of Muscini, where they were also recovered as synapomorphies.
Clade 47 (Fig. 5) was also supported by four non-exclusive apomorphies (Table S2), the reduction of the number of setulae on the fronto-orbital plate (13-2) and the absence of the pd of hind tibia, characters also recovered as apomorphies by Couri and Pont (2000).
Neodexiopsis grade (node 46). The diagnosis/characterization of Neodexiopsis proposed by Malloch (1920) (DC 1+3; scutellum with four setae of equal length; hind tibia with three setae (av, ad, and pd)) was quickly modified. Huckett (1934a) placed Neodexiopsis as a subgenus of Coenosia sensu lato, due to the presence of three preapical setae on the ad, d, and pd surfaces of the hind femur, and placed the species with only preapical ad and pd of the hind femur as Coenosia sensu stricto. This description was preserved by Snyder (1957) but later modified by Couri and Albuquerque (1979), who reincorporated the presence of the three setae ad, d, and pd of the hind tibia as a diagnostic character of the genus Neodexiopsis. The presence of three preapical setae on the hind femur was a synapomorphy observed by Couri and Pont (2000) in a clade made up by three Neotropical genera (Cordiluroides Albuquerque, Harolpdospis Albuquerque, and Neodexiopsis). However, the number of these setae may vary in some species of Neodexiopsis. Recently, in a re-examination of N. rufipes, results showed that the number of preapical setae of the hind femur may be different in males (two setae) and females (three setae) (Patitucci and Couri 2018). In the present study, we analyzed the presence/absence of these three setae independently in males and females (characters 65, 66, 67, 115, and 116), and these were not recovered as synapomorphies for node 46, or for nodes 45 and 51 within this clade. However, the absence of the preapical dorsal seta of the hind femur in males was recovered as an exclusive synapomorphy for its sister clade (node 58), which groups all the remaining species of Coenosia and the above mentioned Neodexiopsis excluded from this clade (node 46, Fig. 5). Three species of Neodexiopsis formed a monophyletic group (node 45, Fig. 5), supported by five non-exclusive apomorphies (Table S2) and its sister group was formed by three Coenosia species and N. rufipes, also supported by three non-exclusive apomorphies (node 51, Fig. 5). At node 45, N. paulistensis was placed as the sister taxon of the species of the Neodexiopsis ovata group (N. genic-ulata and N. neoaustralis). This clade was supported by four non-exclusive apomorphies and three synapomorphies (39-1, 43-1, and 85-2). The presence of a prominent lobe on the anal angle of the wing (39-1) (Fig. 1D) and a glossy area between tergites 3 and 4 (43-1) (Fig. 1E) are morphological structures previously used by Snyder (1958) to define N. ovata group. The third synapomorphy (85-2), i.e., apical margin of the cercus with a bulge (Fig.  3C), is present in other species of the ovata group not included in this work (Neodexiopsis ovata Stein in Huckett 1934a: Fig. 5; and Neodexiopsis parvula Albuquerque in Albuquerque 1958: Fig. 9). On the other hand, node 51 included two Coenosia species (C. curviventris and C. longipede), whose male terminalia are highly similar to the male terminalia of Neodexiopsis species (Patitucci et al. 2021). A more detailed study including more Neodexiopsis species is necessary to better define the limits of this genus.
Coenosia grade (node 58). This group was supported by three synapomorphies. One of them (34-1) was associated with a reduction in the number of setulae between katepisternal setae (Fig. 1C), with a reversal in C. nigerrima. A reduction in the number of setulae between katepisternal setae was also observed by Couri and Pont (2000) as a synapomorphy of the tribe Coenosiini. The two remaining synapomorphies were the absence of the preapical dorsal seta in the hind femur of males (66-1) and females (119-1). This character, which is observed in males and females, is not a very helpful diagnostic character, since it sometimes cannot be correctly differentiated from the respective rows of setae (e.g., anterodorsal preapical seta vs. row of anterodorsal seta); it may be ambiguous (presence, absence or reduction) when numerous specimens are studied (e.g.: C. metalleg) (Patitucci et al. 2021) or it may vary between males (two setae) and females (three setae) as in N. rufipes (Patitucci and Couri 2018).

Coenosia chaetosa group (clade 62).
In a recently study, we proposed this species group, with C. chaetosa, C. inaequalis, C. mallochi, C. metalleg, and C. setiventris based on several structures of males terminalia, among other characters (Patitucci et al. 2021). However, only three of these five species (C. chaetosa, C. inaequalis and C. mallochi,) were recovered in the present analysis as a natural group. Clade 62 is supported by two characters of the male terminalia, considered as part of the diagnosis of this species-group in Patitucci et al. (2021): surstylus longer than broad (91-2) (Fig. 3F), and distal tip of surstylus curved towards cercus (94-1). However, both characters were non-informative and expressed in other terminals as R. rufoapicata and in several Coenosia species (e.g.: C. metalleg + C. aurifera group). In this phylogenetic analysis the absence of pd setae on the hind tibia used by Malloch (1934) to differentiated the Coenosia species from Austrocoenosia species resulted in a non-exclusive apomorphic character at clade 47 (Coenosia + Neodexiopsis). The number and position of the setae in the middle third of the hind tibia, have been used by different authors to characterize and group species within Coenosia (Malloch 1934;Huckett 1934aHuckett , 1934bHennig 1961). Particularly, the presence of a pd setae on the hind tibia was used to originally characterize Neodexiopsis (Malloch 1920) and Austrocoenosia species (Malloch 1934). Snyder (1957) dismissed the character as he considered that the presence of pd setae responded to sexual dimorphism in males of some species of Neodexiopsis. Couri and Pont (2000) also found that the absence of pd setae in the hind tibia was a non-exclusive apomorphy for Coenosia.
Clade 53. Clade 53 included all species treated by Malloch (1934) as Austrocoenosia, C. metalleg and two new species presented in this study. All these species are distributed in the Andean region, principally in the Central Chilean and Subantarctic subregions (Morrone 2015), and were supported by four non-exclusive apomorphies of females. The species at this node were grouped in two clades: node 65 grouped four species: C. metalleg, C. tarsata, C. delneneo sp. nov., and C. aurifera (originally included in Austrocoenosia by Malloch (1934)), and node 52 recovered all species designated by Malloch (1934) within the genus Austrocoenosia, and the new species C. patagonica sp. nov. Clade 65 was supported by six non-exclusive apomorphies (8-1, 81-3, 89-1, 91-1, 94-1, and 102-1), only two of which, absence of the frontal triangle in the frons (8-1) and presence of hairs in the acrophallus (102-1), can be compared with previous information available in the literature. The absence of the frontal triangle in the frons (8-1) is a character state present in all the species of this group, shared with C. bimorpha from the Australasian region and C. argentifrons (Fig. 13B) from the Andean region. These last two species have a silver coloration on the frons; consequently, the frontal triangle could be present but not visible to the naked eye. Some Coenosiinae have silver color frons presumably involved in emitting visual signals (flashes of light) to females or males or other species (Frantsevich and Gorb 2006;Werner and Pont 2006). The second character, presence of hairs in the acrophallus (102-1) (Fig. 3H), which is also present in R. rufoapicata, was observed for the first time in the description of C. metalleg (Patitucci et al. 2021). These hairs can be detected with a stereoscopic microscope under maximum magnification or with SEM and could be sensory structures.
Coenosia aurifera group (clade 69). Coenosia metalleg was recovered as the sister taxon of clade 69 (Coenosia aurifera group), which was supported by five non-exclusive apomorphies (50-2, 51-1, 78-0, 123-1, and 129-0) and three synapomorphies (52-1, 90-1, and 130-1). Tergite 6 and epandrium visible on dorsal view (Fig. 2C), were character states shared only with C. forcipiungula and C. zhongdianensis from the Asian meridional region. Xue and Zhang (2011) described the abdomens of these last two species as cylindrical or long cone-shaped. We found no records in the literature on this conformation of the abdomen in other species of Coenosia. In addition, the abdomen of the species of the C. aurifera group presents a globose epandrium (52-1), which is unique within the genus. This group was defined by two other synapomorphies. One of these synapomorphies was the presence of dorsal spine-like setae on the cercus (90-1) (Figs 6I, 8H, and 10H), which were analyzed with SEM. These spines were coeoloconic sencilla (basiconic pegs or cones that are positioned in shallow pits) and could be related to chemo-sensitive functions (Shields 2010). The other synapomorphy of this clade was the presence of four tergites on segment 6 in the female ovipositor (130-1) (Fig. 4F).
The extension of the female ovipositor and the reduction in the number of tergites area are changes that have occurred independently in different groups of Muscidae, and, according to Hennig (1965), are probably linked with changes in oviposition behavior. This author (op. cit.) also concluded that a long ovipositor along with the reduction in the number of plates (shaped like long rods) in the segments could be an apomorphic characteristic for Coenosia, but clarified that these structures are unknown in several species of Coenosia, particularly in those of the Neotropical region. It is important to highlight that the species of the C. aurifera group present gray coloration with light yellow and/or golden tones, and were collected in open environments outside of forested areas. In addition, in the original description of C. aurifera, Malloch (1934) mentioned various and notorious differences in external appearance (coloration, shape of the last segment of the abdomen in males) that could segregate this species from the others Austrocoenosia species. Many of these characteristics are shared by the other two species grouped with C. aurifera (C. tarsata and C. delneneo sp. nov.).

Coenosia argentifrons group (node 52).
Austrocoenosia species under Malloch's original concept (1934) were recovered as a monophyletic clade supported by four non-exclusive apomorphies (54-1, 76-0, 77-0, and 85-1) and two synapomorphies (87-1 and 131-4). The four non-exclusive apomorphies presented several reversals at different levels of this study and were not informative. The presence of a row of setae in the basal half on the anteroventral surface of the fore femur (54-1) was observed in diverse terminals as R. rufoapicata, some Neodexiopsis species, and Coenosia species from different regions. This structure is associated with predation behavior (Mateus 2012). Sternite 5 much broader than long (76-0) was also a non-informative character. This structure was observed in Coenosia species from the Afrotropical and Nearctic regions. Similarly, characters 77-0 and 85-1 (both structures associated with the cercus), were non-informative and observed in several species of Neodexiopsis and Coenosia from different regions. On the other hand, the two synapomorphies found constitute new elements at the subfamily level. The presence of keels on the cercus in male genitalia (87-1) (Fig. 3B), previously identified in C. argentifrons by Couri and Nuñez (2001), constitutes a diagnostic element of the C. argentifrons group, since this structure has not been observed in any other Coenosiinae. In a recent study, we proposed the cercus with keels could form the "fourth morphological pattern" and that this structure could be considered as a central element to classify or group species within Coenosia (Patitucci et al. 2021). Similarly, females present erythrocyte-shaped spermathecae (131-4) (Fig. 4K), which differ from the three forms observed for Muscidae (Couri 1998). It is unknown whether the variation in sperm shape influences the number, size, or storage type of sperm, or whether it differentially affects sperm attraction, competition, or selection (Pascini and Martins 2017). Our data set supported the monophyly of all the species previously ascribed to Austrocoenosia under Malloch's original concept (1934) (with the exception of C. aurifera), conforming a clade inside the genus Coenosia. Undoubtedly, the singularities observed could be correlated with the fact that this group is endemic to the Andean region.
Our present study did not aim to resolve the complex intrinsic relationships within Coenosia; however, our results suggest that the structures of male and female genitalia can provide more robust results to clarify these relationships, and also provide a reinterpretation of the different groups of species in the different biogeographic regions of the world.
These comments are also valid to be able to understand and analyse in future investigations, the relationships within Coenosiini, and in particular the phylogenetic position of the species included in Neodexiopsis.
It would be important that, in addition to the external morphological characters, especially from leg chaetotaxy which had been considered of importance in previous studies (Couri and Pont 2000), future studies should incorporate the structures of female and male terminalia as well as additional molecular data and also data from immature stages, which will certainly contribute to the understanding of the relationships within this clade.