Revision of the Afrotropical genus Fainia Zumpt, 1958, with notes on the morphology of Rhiniidae subfamilies (Diptera, Oestroidea)

Abstract The taxonomy and diversity of Fainia Zumpt, 1958, an exclusive Afrotropical genus, had not been reviewed recently. The genus included six nominal species, but the status of several of them was debated. Identification of most Fainia species depends on characters of the male terminalia; females are poorly known and, in several cases, are not adequately diagnosed. We conducted a taxonomic revision of the genus and generated identification tools. Based on the study of type material and specimens available in entomological collections in Africa and Europe, we recognise here three of the six species as valid (F. albitarsis (Macquart, 1846), F. elongata (Bezzi, 1908) and F. inexpectata Zumpt, 1973). We also provide an identification key to both sexes, redescriptions of the species, updated distribution records and high resolution photographs of males’ and females’ habitus and male terminalia. The description of Fainia kagerana Lehrer, 2007a nom. nud. is an invalid nomenclatural act in terms of ICZN Article 13.1.1. Based on examinations of their holotypes, F. sambura Lehrer, 2008 syn. nov. is proposed as a junior synonym of F. albitarsis; F. kirinyaga Lehrer, 2007b syn. nov. is proposed as a junior synonym of F. inexpectata; and Fainia giriama Lehrer, 2007b is moved from the genus Fainia to the genus Rhinia Robineau-Desvoidy, as Rhinia giriama (Lehrer, 2007b) comb. nov.. We propose two apomorphies that support the status of the subfamily Rhiniinae.

There is very little information on the diversity, biology and distribution of the Rhiniidae. The life cycle and, in particular, the habits and larval morphology are unknown for most of the species (Cuthbertson 1933(Cuthbertson , 1934Kurahashi and Kirk-Spriggs 2006;Peris 1952;Zumpt 1958). What is known is limited to a few species that are restricted to specific geographic regions. In general, some species have a strong association with natural environments; adults are flower visitors and are thought to be important pollinators; and some species seem to have a close relationship with termites (Arce et al. 2019;Kurahashi and Kirk-Spriggs 2006;Ferrar 1987).
We present a morphological revision of Fainia, including a taxonomic study; an update of nomenclature with morphological considerations of key characters; an identification key; redescriptions; and high quality photographs of males' and females' habitus and male terminalia. We propose two apomorphic characters of the phallus that allow diagnostic differentiation of Rhiniinae.

Preparation and taxonomic revision of specimens
Pinned and ethanol-preserved specimens were examined using stereomicroscopes (Leica M80 and Leica MZ95) with an ocular micrometer and external LED illumination. Identifications and reidentifications were made following Peris (1952), Zumpt (1958Zumpt ( , 1973 and Lehrer (2007aLehrer ( , 2007bLehrer ( , 2008Lehrer ( , 2011. Females were identified by morphological comparison with males and the species' descriptions and corroborated using DNA barcodes (Thomas-Cabianca et al., unpublished). Male terminalia were dissected following Rognes (2009) and Cerretti and Pape (2012), stored in small plastic microvials filled with glycerine and pinned or preserved together with their respective specimens. Measurements made in this study are summarised in Fig. 4.

Identification tools
The taxonomic key and descriptions were based on a morphological character matrix built using the DELTA (DEscription Language for TAxonomy) software (Dallwitz 1980a, b, Dallwitz et al. 1999) and building on leads from the DELTA-IntKey module (Dallwitz et al. 2000).

Composite macro-microphotographs
Adult specimens were photographed using a Canon-EOS 6D reflex camera with Canon MP-E 65 mm f/2.8 1-5 lens (ISO 200, f/5.6-9, V:1/160) installed on a copy table with an automatic macro-metric rail and external artificial light or using a Canon-EOS 7D camera with K2-P1CF2 lenses and a P-51 Camlift controller, version 2.8.0.0 (Copyright Roy Larimer/Dun.inc.2014). Photographs included habitus (dorsal and lateral views), head (frontal and lateral views) and abdomen (dorsal and lateral views). Additional photographs of important morphological structures were also taken. Between 15 and 60 high-resolution pictures (in RAW or TIFF format) were taken to cover all of the focal planes needed for focus stacking. Male terminalia were photographed using a stereomicroscope with an integrated Leica M205C camera and coupled DFC450 camera and a Leica Z16AP0A macroscope with coupled Leica DFC490 camera. Photographs included the epandrium, cerci and surstyli (dorsal and lateral view), phallus (lateral, dorsal and ventral view), postgonite and pregonite (lateral view), ejaculatory sclerite (if available) and fifth sternite. Images were processed using Adobe Photoshop Lightroom CS6, stacked with Zerene Stacker, edited with Adobe Photoshop CS6 and measured with IMAGEJ.

Information provided
For each species we provide: valid name, synonyms, diagnosis (included in the identification key), type locality and type repository (including primary types), distribution, biology, redescriptions of male and female, material examined and photographs. Previously unpublished records obtained from the material examined are indicated by an asterisk (*). Some countries are marked with a '?' when the report was a museum database record that showed discrepancies after our examination of the relevant specimen(s).
Discussion. Fainia albitarsis is widely distributed in the Afrotropical Region. It was adequately diagnosed by Peris (1952) and redescribed by Zumpt (1958), but the illustrations of sternite 5 are incongruent between the two authors. Photographs of sternite 5 (Fig. 6F) are provided here for a proper determination of the species. The HT or STs were found to be destroyed by pests at MNHN. Additionally, the HT or STs of F. eupoda were not found in ZMHB and we consider it missing. The specimen assigned as HT of Idia eupoda in ZMHB is labelled as 'Pr. b. sp Krebs // 4532 // Type (red-label) // eupoda Loew*'; 'Pr. b. sp' refers to Promontorium bonae spei, Latin for "Cape of Good Hope'' in South Africa and it was collected by Ludwig Krebs (1792-1844), Cape naturalist to the King of Prussia. This differs from the published type locality and collector: Inhambane, Mozambique leg. Peter, suggesting that the specimen is, in fact, not a type. Specimens from Democratic Republic of the Congo, Kenya and South Africa (see material examined section) identified by Knut Rognes, together with the description of Zumpt (1958), were used for the proper determination of this species. As the descriptions were adequate for identification, neotypes are not required for Fainia albitarsis or Idia eupoda. The synonymy of Idia extensa was first published by Peris (1952), and seems reliable.
The description of Fainia kagerana nom. nud. is an invalid nomenclatural act in terms of ICZN Article 13.1.1 because it lacks a comparative diagnosis. In addition, the descriptions and drawings of F. kagerana nom. nud. (Lehrer 2011: 59-61) (Fig. 13C, E, I) and F. sambura syn. nov. (Lehrer 2011: 63-65) (Fig. 13B, F, H) match the morphology of F. albitarsis. On examining the F. sambura syn. nov. HT, including the male terminalia (dissected by Lehrer) (Fig. 7), we found that the surstyli, cerci and ventral plate exhibit the same diagnostic characters as described above (Fig. 6A, B). Careful examination of the ventral plate of the phallus revealed that the structure is articulated, with the joint located within the basi-and distiphallus membranous con-nection. This articulation can produce different orientations of the ventral plate in lateral and ventral views of the phallus, obscuring their typical 'M' shape visible in ventral view in various specimens. The phallus drawings of F. kagerana nom. nud. (Lehrer 2011: fig . 36D) and F. sambura syn. nov. (Lehrer 2011: fig. 39D) show different orientations of the ventral plate in lateral view, suggesting that they could be different species. The 'M' shape of the ventral plate can be clearly observed in the specimen of F. kagerana nom. nud. (Figs 6E, 7E) and partially observed in the HT of F. sambura syn. nov. as it was partially damaged (it was crushed between the lid and wall of the microvial) (Fig. 7J). Based on this evidence, we conclude that F. sambura is synonym of F. albitarsis and F. kagerana nom. nud. corresponds to F. albitarsis.
Biology. Ecology, immature stages and life history unknown. Redescription. A proper and complete description with male terminalia illustrations was given by Zumpt (1973). Here, we provide additional diagnostic characters, based on measurements and discuss the sternite 5 shape. Length 10.56 mm [10.14-11.13 mm] (n = 4). Male (n = 2). Head (Figs 10A and C (Figs 11,12). Sternite 5 posteriorly formed by 3 lobes, 1 median and 2 outers (Figs 11F, 12F). Median lobe as Figs 11F, 12F and H, posterior margin triangular with a middle incision inwards, that could be slightly torn (Figs 11F,12H) or not (Fig. 11F). Lateral lobes shorter than F. elongata, as in Fig. 9F. Surstylus and cercus as Fig. 11A, B. Phallus as in Fig. 11C-E, ventral plate in ventral view as in Fig. 11E; post-and pregonite as in Fig. 11G. Female. (n = 1). Head (Fig. 10B, D). Eyes separated by 0.20 times width of head; eye length 3.93 times height of gena. Postpedicel length 2.46 times pedicel length; fronto-orbital plate 0.70 as wide as frontal vitta at tip of ocellar triangle.    Discussion. Fainia inexpectata is an uncommon Afrotropical species. The male terminalia were dissected by Zumpt and are preserved in a slide mounting preparation. The preserved terminalia are squashed and the structures overlap, so it was impossible to make a proper examination. Thus, the male terminalia structures were recognised and identified using a drawing provided by Zumpt (1973: fig. 4).

Rhinia giriama
Distribution. Kenya (Lehrer 2007b). Biology. Ecology, immature stages and life history unknown. Discussion. This is the only species described by Lehrer in Fainia that was based on a single female specimen. After examining the HT of F. giriama (Fig. 14), we conclude that it belongs to the genus Rhinia. The specimen is characterised by having wing cell r 4+5 closed with a long petiole and apical area darkened, fore and mid first tarsomeres dark and palpi long, narrow and uniform in width, generally yellow (Fig. 14A, C). These characters fit the concept of the genus Rhinia (Zumpt 1958;Peris 1992) and not Fainia (see diagnosis above).
More recently, in addition to the traditional characters used to split the two primary lineages of Rhiniidae (Peris 1952;Zumpt 1958;Kurahashi and Kirk-Spriggs 2006), Fang and Fan (1988) incorporated characters of the phallus. In Cosmininae, the acrophallus is often connected with the base of the hypophallus (= mid-ventral wall) and the epiphallus is developed, while in Rhiniinae, the acrophallus stretches out from the paraphallus and the epiphallus is undeveloped.
Recent molecular evidence, based on DNA Ultra Conserved Element (UCE) sequence data, reconstructed three major clades within Rhiniidae, with Cosmininae split into two clades (one containing the exclusive Oriental genus Sumatria and the other, the rest of the Cosmininae genera) and Rhiniinae monophyletic (Buenaventura et al. 2020). In our examination of all of the Afrotropical rhiniids, two morphological characters in the phallus support potential synapomorphies for the Rhiniinae (Table 1). First, the absence of an epiphallus is apomorphic in Rhiniinae, as was also suggested by Fang and Fan (1988) and the epiphallus is present (pleisomorphic state) in other Table 1. Proposed apomorphies (in bold) for Rhiniinae, polarised using the character state found in Bengaliinae (Diptera: Calliphoridae) (Rognes 2009) and Afrotropical Cosmininae (Buenaventura et al. 2020 Rhiniidae and its sister group Bengaliinae (Calliphoridae) (Rognes 2009;Cerretti et al. 2019;Kutty et al. 2019;Buenaventura et al. 2020). Second, the basi-and distiphallus are connected by a desclerotised membrane, which is apomorphic in Rhiniinae, whereas they are plesiomorphically fused in other Rhiniidae and Bengaliinae (Rognes 2009).