Microcerella, , Macquart, 1851

Microcerella View in CoL clade

This clade, represented by the species R. argentina and the genera Austrophyto , Boettcheria and Microcerella , received strong JK value and is supported by nine uniquely derived character states including: (1) arista plumose in at most basal half ( Fig. 47C, D View Figure 47 ), (2) thorax with metallic grey/golden stripes (highly contrasting relative to the blackish background), (3) anepimeral area with four strong setae and sparse, weak setulae, (4) male abdominal T5 higher than other abdominal tergites, (5) male ST5 with a rounded or pointed lobe on the anterior half (no. 1 in Fig. 47E View Figure 47 ), (6) male ST5 with cleft margin swollen (no. 2 in Fig. 47E View Figure 47 ), (7) male ST5 with a fold along the cleft margin (no. 3 in Fig. 47E View Figure 47 ), (8) surstylus two to three times longer than wide and (9) phallus with a rigid sclerotized area ventrally between basi- and distiphallus (arrow in Figs 29F View Figure 29 , 47F View Figure 47 ). Three homoplasies also support this clade, including male with rows of frontal setae diverging anteriorly [also found in the genera Lepidodexia , Lipoptilocnema , Sarcophaga , Spirobolomyia and Udamopyga (including Carinoclypeus )], as well as parafacial plate with strong setae (also found in Helicobia ). From the eight autapomorphies supporting the entire Microcerella clade, character state 8 was included as characteristic for Boettcheria species by Dahlem & Downes (1996). Similarly, the character states 1 and 8 were included as diagnostic features for the genus Microcerella by Mulieri et al. (2015). Also, both Dahlem & Downes (1996) and Mulieri et al. (2015) illustrated the male ST5 with a rounded or pointed lobe on the anterior half (autapomorphy 4) in several species of Boettcheria and Microcerella , respectively; however, they did not consider it as diagnostic for these genera. Interestingly, a similar lobe on the anterior half of the male ST5 was considered as diagnostic for the genus Austrophyto by Mulieri (2017).

Our analysis recovered a monophyletic genus Boettcheria as sister to the clade ( Microcerella + ( Austrophyto + R. argentina )). Based mostly on male terminalia characters, Roback (1954) placed Boettcheria close to Sarcodexiopsis and Tripanurga and included these genera in the subtribe Boettcheriina . Lopes (1983) placed this subtribe within Sarcophagini , but he restricted Boettcheriina to species of Boettcheria , and in the same publication he suggested a possible relationship between Boettcheriina and Microcerellini , this last tribe containing species with ‘bare or pubescent arista’. In a subsequent publication, Lopes (1989) described Austrophyto as a monospecific genus and placed it into the tribe Microcerellini . Pape (1990) synonymized all the generic names included in the Microcerellini of Lopes (1983) under Microcerella , excluding only Cryptosarcophila Townsend (transferred to Lepidodexia as a subgenus) and Austrophyto . Pape (1994) found Boettcheria as sister to Emdenimyia , a relationship supported by the configuration of postero-ventral setae on the trochanter (see discussion of the Blaesoxipha clade), but he did not include Austrophyto or any species of Microcerella . Based on molecular data, Kutty et al. (2010) found Boettcheria cimbicis (Townsend, 1892) as part of a trichotomy with Engelimyia inops (Walker, 1849) and Tricharaea femoralis (Schiner, 1868) ; Stamper et al. (2012) recovered a monophyletic Boettcheria as sister to T. importuna , and Piwczyński et al. (2014) recovered a sister-group relationship between a monophyletic Boettcheria and E. inops . Thus, molecular data do not yet converge in their phylogenetic estimations with regard to the position of Boettcheria , while the morphological data of Giroux et al. (2010) coincide with ours in placing Boettcheria and Microcerella as closely related taxa.

Lopes (1950) revised the species of Boettcheria and provided a definition for this genus, where he highlighted the characteristic shape of the male ST5 and the very large vesica. Pape (1989b) redefined this genus and proposed a diagnosis including four character states. In a subsequent revisionary work of the Nearctic species of Boettcheria, Dahlem & Downes (1996) provided a generic definition based on three character states. Pape (1996) proposed a diagnosis for Boettcheria , in which he included some of his own character states ( Pape, 1989b) and also those of Dahlem & Downes (1996). Here we included all of Pape’s (1996) diagnostic character states, of which two were reinterpreted and combined into one character state. Our analysis resulted in five autapomorphies supporting this genus. Pape’s character state of the modified setae on the male hind trochanter is separated into two character states, with male hind trochanter with a postero-ventral brush-like clump of short, stubby setae distally (position as no. 1 in Fig. 45 View Figure 45 ) coming out as an autapomorphy for Boettcheria . The remaining four autapomorphies are: (1) six or more frontal setae below posterior limit of the lunule, (2) male abdominal T5 higher than other abdominal tergites, (3) vesica convoluted ( Fig. 30F View Figure 30 ) and (4) juxta squared with proximal corners slightly elongated ( Fig. 30F View Figure 30 ). Character state 3 may be seen as a simplified way of describing the most complex structure in the male terminalia of species of Boettcheria . The vesica in this genus has been previously described as ‘trilobed’ ( Dahlem & Downes, 1996) or ‘with more than three lobes’ (Giroux et al., 2010); however, any subdivision into lobes or a more detailed definition of this structure would require a homology assessment based on a more inclusive sample of species, which is not the scope of our study. Additional characters with potential phylogenetic content are (1) the unusually larger membranous area between the epandrium and the proximal margin of the surstylus and (2) the L-shaped surstylus in most species of this genus.

The sister-group relationship between ( Austrophyto + R. argentina ) and Microcerella received strong JK value and is supported by two autapomorphies: (1) male hind trochanter with a pad of short setae covering almost the entire posterior surface (position as no. 3 in Fig. 45 View Figure 45 ) and (2) phallus with a paler ventral area between basi- and distiphallus (arrow in Figs 38E View Figure 38 , 47G View Figure 47 ).

Mulieri (2017) revised Austrophyto and provided a definition for this genus, where he highlighted several features, most of them found in many other genera in Sarcophaginae , but also including the (1) postgonite with two long setae, (2) distiphallus with a swollen, desclerotized ventral area proximal to vesica, (3) vesica short and weakly sclerotized, with a microserrated margin and (4) juxta scarcely developed, with apico-lateral membranous lobes and a medial sclerotization (= medial juxtal sclerite) between them. Character state 1 was included here in its original form, while state 2 was included as homologized with paler ventral area between basi- and distiphallus being swollen in Austrophyto and R. argentina , state 3 was included as vesica with a proximal desclerotized, microserrated and bilobed section (‘vbs’ in Fig. 38E, G View Figure 38 ) and state 4 was divided into median juxtal sclerite (‘mjs’ in Fig. 38F, G View Figure 38 ) and juxta as two apico-lateral membranous lobes (‘jl’ in Fig. 38F–H View Figure 38 ). Mulieri (2017) also highlighted the distiphallus with ‘strongly developed harpes’, which were not included here due to lack of material. However, the harpes in this genus are conspicuous with a shape not observed in other genera of Sarcophaginae . Mulieri (2017) also compared the reduced juxta of Austrophyto with that of Boettcheria ; however, we do not find support for the latter genus having a juxta reduced nor morphologically similar to that of Austrophyto . Some additional comments by Mulieri (2017) on the possible phylogenetic relatedness of Austrophyto to Boettcheria and Microcerella were not endorsed by phylogenetically informative evidence and are considered unsupported. Our analyses reconstructed the monophylum of ( Austrophyto + R. argentina ), which received strong JK value and is supported by five autapomorphies: (1) postgonite with two long setae ( Fig. 38D View Figure 38 ), (2) paler ventral area between basi- and distiphallus swollen (arrow in Fig. 38E View Figure 38 ), (3) vesica with a proximal desclerotized, microserrated and bilobed section (‘vbs’ in Fig. 38E, G View Figure 38 ), (4) median juxtal sclerite (‘mjs’ in Fig. 38F, G View Figure 38 ) and (5) juxta as two apico-lateral membranous lobes (‘jl’ in Fig. 38F, G View Figure 38 ). The affinity of R. argentina was uncertain also for Lopes (1988b), who assigned it provisionally to Retrocitomyia in spite of the absence of terminalia features typical of that genus. Based on our phylogeny and morphological examinations, we propose to include R. argentina in Austrophyto , with Austrophyto argentina (Lopes, 1988) as a new combination.

Previous definitions for Microcerella ( Macquart, 1851; Hall, 1937; Lopes, 1983; Pape, 1996) were considered as ‘skewed’, ‘based on highly homoplastic characters’, and as considering only ‘few and unuseful character states’ ( Mulieri et al., 2015). However, subsequent definitions for this genus included some character states such as ‘male without orbital proclinate setae’ ( Mulieri et al., 2015), which is not diagnostic for this genus, since it is found in at least 37 genera of Sarcophaginae . Outlining a definition for this and other Sarcophaginae genera compels researchers to use homoplasies, which are abundant in the subfamily, as already reported (Giroux et al., 2010). This overwhelming level of homoplasy could have resulted from multiple specializations giving morphologies that retain few clues to their phylogenetic history.

In the description of the genus Microcerella, Macquart (1851) used the bare arista to define this taxon, which was also included in definitions proposed by subsequent authors ( Hall, 1937; Lopes, 1983; Pape, 1990, 1996). Pape (1990) defined Microcerella by the following character states: (1) eyes green, (2) syntergosternite 7 + 8 black, (3) hypandrium swollen at level of pregonite, (4) postgena with at least some black setae close to genal suture, and he also pointed to the (5) syntergosternite 7 + 8 dark brown to black/ epandrium red. Pape (1996) added two other character states: (6) strong parafacial setae, and (7) arista almost bare. Mulieri et al. (2015) included (8) three strong postsutural dorso-central setae, (9) rigid connection between basi- and distiphallus, fused anteriorly with an incomplete hinge on posterior part, and (10) phallus with a paler anterior (= ventral) area between disti- and basiphallus. From these ten character states, 1, 3 and 5 came out as autapomorphic for this genus in the present study, while character state 2 was also found in Boettcheria and 10 was also found in Austrophyto , character states 7 and 9 were autapomorphic for the entire Microcerella clade and states 4, 5, 6 and 8 were homoplasious. Besides character states 1, 3 and 5, the monophyly of Microcerella was also supported by the paler and flat ventral area between basi- and distiphallus ( Fig. 47G View Figure 47 ) (swollen in Austrophyto ), and the juxta campanulated to oval ( Figs 29F, G View Figure 29 , 47G View Figure 47 ).