Mesembrinellidae Shannon, 1926

Whitworth, Terry L. & Yusseff-Vanegas, Sohath, 2019, A revision of the genera and species of the Neotropical family Mesembrinellidae (Diptera: Oestroidea), Zootaxa 4659 (1), pp. 1-146 : 16-18

publication ID	https://doi.org/ 10.11646/zootaxa.4659.1.1
publication LSID	lsid:zoobank.org:pub:57309E14-0330-4ED7-BCDA-355EE6618215
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scientific name	Mesembrinellidae Shannon, 1926
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Family Mesembrinellidae Shannon, 1926 View in CoL

Diagnosis. This is a morphologically diverse family with species ranging from 7 to 17 mm in body length, sharing many characters with Calliphoridae . Thorax usually subshiny, blue, tan or brown, sometimes with pale to tan tomentose stripes. Abdomen often with shiny blue to brown cuticle with pale tomentum. Anterior thoracic spiracle normally ovate, with a broad oval opening above ( Fig. 5 View FIGURES 1–8 ); in a few species the anterior spiracle has a long, narrow opening gradually widening above ( Fig. 6 View FIGURES 1–8 ). Posterior thoracic spiracle varying in size from small to large, reniform (= kidney-shaped), with an opening midway along upper margin and a fringe of long, ventrally-directed setae ( Fig. 7 View FIGURES 1–8 ). Most species have a subscutellum ranging from weakly to moderately or prominently developed, different from the closely related Calliphoridae where the subscutellum is not developed or at most weak. Row of meral setae in shape of an inverted L, with setae ranging from pale and fine to dark and stout ( Fig. 7 View FIGURES 1–8 ). Horizontal portion of inverted L usually composed of about 5 or more setae, in some species shorter, composed of only 2–3 setae or, rarely, absent. Wing with bend of vein M evenly curved (usually forming an obtuse angle, Figs 1, 3 View FIGURES 1–8 ) in most species, vs. normally angulate (at a right or acute angle) in Calliphoridae ( Fig. 4 View FIGURES 1–8 ). Frons width typically much narrower in males than in females, with frons to head ratios often providing valuable species-specific characters. Female frons broader, with width ranges often overlapping between species. Female with cruciate (crossed) setae just anterior to ocellar triangle. Male terminalia: most species with a roughly rectangular or square-shaped epandrium and medium-sized surstylus and cercus, adjacent at base ( Figs 15 View FIGURES 15–20 , 55 View FIGURES 53–56 , 63 View FIGURES 63–68 , 87 View FIGURES 87–92 ); in the spicata -group the epandrium is elongate and the surstylus and cercus are tiny ( Figs 27, 29 View FIGURES 27–32 ); in the bolivar -group there is a narrow neck between the epandrium and the (swollen) base of the cercus, with surstylus and cercus widely separated in lateral view ( Figs 31 View FIGURES 27–32 , 33 View FIGURES 33–38 ); in the anomala -group the epandrium is reduced and the surstylus is enlarged ( Fig. 99 View FIGURES 99–102 ). In most species the phallus is slender with epiphallus of various lengths and shapes, from long and slender ( Fig. 105 View FIGURES 105–114 ) to short and blunt ( Fig. 165 View FIGURES 163–172 ); hypophallic lobes often of unique shape from rounded ( Fig. 106 View FIGURES 105–114 ) to oval ( Fig. 111 View FIGURES 105–114 ) or rectangular ( Fig. 182 View FIGURES 173–182 ); in a few species the phallus is highly modified ( Figs 117–120 View FIGURES 115–124 ). In males of most species ST1 is broad, ST2–4 are gradually narrowing (e.g., Fig. 239 View FIGURES 239–251 ) and ST5 is usually broad and bilobed, sometimes modified ( Figs 239, 245, 247, 249 View FIGURES 239–251 ). Female with ST1–5 oval to nearly square or rectangular ( Figs 411–454 View FIGURES 411–423 View FIGURES 424–438 View FIGURES 439–453 View FIGURE 454 ). Female postabdomen not telescopic; dorsum of ovipositor with large T6, ranging from a flattened (e.g., Fig. 282 View FIGURES 282–287 ) to a regular U or V shape (e.g., Fig. 287 View FIGURES 282–287 ), often with distinctive spiracles; T7 smaller and either bilobed ( Fig. 282 View FIGURES 282–287 ) or divided ( Fig. 289 View FIGURES 288–293 ); T8 much reduced, divided ( Fig. 284 View FIGURES 282–287 ) or continuous ( Fig. 303 View FIGURES 300–305 ); epiproct and cerci as in Figs 282–325 View FIGURES 282–287 View FIGURES 288–293 View FIGURES 294–299 View FIGURES 300–305 View FIGURES 306–311 View FIGURES 312–317 View FIGURES 318–323 View FIGURES 324–325 . Venter of ovipositor composed of ST6, ST7, a greatly reduced ST8, and hypoproct ( Fig. 326 View FIGURES 326–349 ). Spermathecae (three in number) of three distinctive types: filiform ( Figs 375–396 View FIGURES 370–400 ; most species), tuberform ( Figs 370–374 View FIGURES 370–400 ; genus Laneella , though significantly shorter in L. fuscosquamata ), or bulbous ( Figs 397 View FIGURES 370–400 , 410 View FIGURES 401–410 ; M. flavicrura and Souzalopesiella facialis ).

Status of genera in Mesembrinellidae . Several studies have questioned the validity of most of the genera in the family ( Vargas & Wood 2009; Moll 2014; Marinho et al. 2017). It has even been argued that only the genus Mesembrinella should be retained as valid ( Cerretti et al. 2017). We accept Marinho’s synonymy of Eumesembrinella with Mesembrinella ( Marinho et al. 2017) . Based on our study of specimens of most previously described species and of the fifteen new species described herein, we retain three subfamilies, Laneellinae, Mesembrinellinae and Souzalopesiellinae, and three genera, Laneella , Mesembrinella and Souzalopesiella . We synonymize the genera Albuquerquea , Giovanella , Henriquella , Huascaromusca and Thompsoniella with Mesembrinella , and species of Mesembrinella are classified within six groups: the M. latifrons -group, the M. spicata -group, the M. bolivar -group, the M. aeneiventris -group, the M. bicolor -group, and the M. anomala -group. These groupings help us discuss species in a logical manner, but they are tentative and we are aware that future phylogenetic studies may suggest further changes in the classification. Characters of each species-group are discussed in detail further on.

Remarks. The detailed key below can be used to separate Mesembrinellidae from Neotropical Calliphoridae . The reniform posterior spiracle readily distinguishes mesembrinellids from calliphorids, sarcophagids and tachinids. Other features of sarcophagids are the three conspicuous black stripes on a gray- to gold-pruinose thorax and the checkered abdomen. Sarcophagids typically also have two larger and two smaller notopleural setae on the notopleuron, whereas mesembrinellids have only two stout notopleural setae. Tachinids have a prominently developed subscutellum, rare in mesembrinellids, and normally they have a bare arista (except in Dexiini), which is setose in mesembrinellids. Other similar flies include muscids, which sometimes have a posterior spiracle similar to mesembrinellids but lack meral setae, always present in mesembrinellids.

The keys to genera and species of Mesembrinellidae provided herein were developed following Guimar„es (1977), and are the first comprehensive taxonomic keys for the family Mesembrinellidae published since then.