Peckiamyia, Dodge, 1966

Peckiamyia View in CoL clade

This clade, which received aBS but no JK, is composed of the genera Duckemyia , Peckiamyia , Retrocitomyia , Sinopiella and Tapacura . The Peckiamyia clade splits into clade 73 (genus Sinopiella ) and clade 74. The latter clade has the genus Tapacura as sister to ( Retrocitomyia + ( Duckemyia + Peckiamyia )). Duckemyia (monospecific), Peckiamyia , Sinopiella and Tapacura are recovered as monophyletic. The Peckiamyia clade is supported by one autapomorphy: phallus shorter than or of almost equal length to pregonites. The presence of a three-lobed vesica composed of a proximal section (divided or not) and a pair of vesical lateral arms ( Figs 10G View Figure 10 , 16F View Figure 16 , 21F View Figure 21 , 35E View Figure 35 , 36B View Figure 36 ) also supports this clade, although it is not an autapomorphy. Our results are in agreement with Tibana & Lopes (1985), who highlighted similarities in the small size of the phallus of Peckiamyia , Retrocitomyia , Sinopiella and Tapacura . These authors also found similarities between Sinopiella and the subgenus Titanogrypa (Cucullomyia) , but we did not find support for this assertion. Our results are consistent with those of Piwczyński et al. (2014), where Duckemyia and Peckiamyia emerged as sister groups.

Within the Peckiamyia clade a sister-group relationship was found between the monophyletic Sinopiella and the remaining genera, arranged in clade 74. The genus Sinopiella is represented in our analysis by its two known species, and it emerges as monophyletic (clade 73 in Fig. 2B View Figure 2 ). While all other genera of the Peckiamyia clade have hillae, the lateral styli in the genus Sinopiella are simple and exhibit no modifications. The monophyly of this genus received strong branch support, and its eight autapomorphies are all in the male terminalia: (1) postgonite slightly swollen, (2) postgonite enlarged, (3) pregonite dorso-ventrally flattened and concave, (4) paraphallus humped postero-distally ( Fig. 21D View Figure 21 ), (5) vesica three-lobed with a proximal section undivided and lobe-shaped ( Fig. 21F View Figure 21 ), (6) vesical lateral arms elongated with rounded apex ( Fig. 21F View Figure 21 ), (7) juxta deeply recessed within the phallic tube ( Fig. 21D–F View Figure 21 ) and (8) juxta squared with ventral margin pointed ( Figs 5G View Figure 5 , 21F View Figure 21 ). In the description of this genus, Lopes & Tibana (1982) suggested a close relationship with Peckiamyia based on the short phallus, which is supported by our results. In the same publication, these authors also suggested a relationship between Sinopiella and Retrocitomyia due to both genera sharing enlarged pregonites. Although both these genera are closely related as members of the Peckiamyia clade, this sister-group relationship is not recovered in our phylogeny, as the enlarged pregonites were observed only in Retrocitomyia , while Sinopiella has normal-sized pregonites and enlarged postgonites. Kutty et al. (2010) found strong support for a sister-group relationship between Sinopiella rotunda (Lopes & Ferraz, 1991) and Lepidodexia (Notochaeta) sp., but here all species of Lepidodexia form a single clade not closely related to Sinopiella . Finally, the three character states (male mid-femur with ctenidium of rounded spines, wing with third costal sector bare ventrally and three conducting styli) listed by Pape (1996) are not diagnostic for this genus.

Clade 74 received weak JK value and is supported by the following autapomorphic character states: (1) hillae directed distally ( Figs 16F, G View Figure 16 , 35C, E View Figure 35 ), (2) hillae paddle-like ( Figs 16F View Figure 16 , 35C–E View Figure 35 ), (3) only apex of hillae attached to the inner paraphallic wall ( Figs 16F View Figure 16 ) and (4) juxta squared with anterior margin even ( Figs 16H View Figure 16 , 35F View Figure 35 , 36E View Figure 36 ). The presence of proximal expansions of the lateral styli or hillae in clade 74 is homoplasious in our analysis and appears to have evolved in the ancestor of the Tricharaea grade or earlier, becoming reduced in clade 38, and reappearing in clade 74. Generally, the hillae are visible ( Fig. 16F–H View Figure 16 ) in lateral view in Duckemyia , while in Peckiamyia , Retrocitomyia and Tapacura they remain hidden by the lateral wall of the distiphallus. In some species of the last three genera, the hillae are distally attached to the inner wall of the juxta, leaving two low swellings that are visible in dorsal view (arrows in Fig. 28A View Figure 28 ). Clade 74 is also supported by the presence of a three-lobed vesica, whose proximal section is undivided and arch-shaped in Duckemyia ( Fig. 16F View Figure 16 ), Retrocitomyia ( Fig. 10G View Figure 10 ) and Tapacura ( Fig. 36B View Figure 36 ), while in Peckiamyia this section has a shallow proximal division giving two joined lobes ( Fig. 35D, E View Figure 35 ).

Tapacura is reconstructed as a monophyletic taxon with weak JK value but supported by two autapomorphies: (1) vesical lateral arms disc-shaped ( Fig. 36A, B View Figure 36 ) and (2) juxta squared with anterior margin even and flat ( Fig. 36E View Figure 36 ). This genus has very small and distinctive male genitalia, which may carry informative characters for supporting its monophyly. Species of Tapacura have lateral plate-like structures completely fused to the paraphallic wall and with a distal cleft ( Fig. 36A–C, E View Figure 36 ). The homology of these structures is uncertain. These plate-like structures are in a similar position than the paraphallic blinkers. However, they lack the landmark for delimiting these blinkers, which is a desclerotized strip between them and the ventral margin of the paraphallus. Also, the lateral plates of Tapacura are completely sclerotized, while the paraphallic blinkers are semi-sclerotized.

A sister-group relationship between Retrocitomyia (excluding Retrocitomyia argentina Lopes, 1988 ) and ( Duckemyia + Peckiamyia ) was recovered in our analysis (clade 76 in Fig. 2B View Figure 2 ). Clade 76 is supported by two uniquely derived apomorphies: (1) cercal prong S-shaped with uni- or bilobed apex ( Fig. 40H View Figure 40 ) and (2) postgonite directed perpendicular to body axis.

The monophyly of Retrocitomyia (excluding R. argentina ) is strongly supported in our analysis by four autapomorphies: (1) cercal prong bilobed with a blunt tip (see arrows in Fig. 47A View Figure 47 ), (2) cercal prong without dorso-medial setae, (3) vesical lateral arms paddle-like with a hook-shaped apex and (4) juxta squared with anterior margin even, undulated dorso-ventrally or with a medial folding ( Figs 10G, H View Figure 10 , 28A View Figure 28 ). The two tips of the bilobed cercal prong might be more developed in some Retrocitomyia species than in others. Lopes (1983) assigned Retrocitomyia , together with Chlorosarcophaga and Dexomyophora (both included in Lepidodexia [s.l.] by Pape [1996]), and Udamopyga , to the subtribe Udamopygina based on various features of the cephaloskeleton of the first-instar larva, a concavity in ST8 of the female, the presence of ‘large lateral plates’ on the distiphallus and the absence of a vesica. Our results did not support a relationship between Retrocitomyia , Lepidodexia and Udamopyga , and each of these genera emerged within separate, distantly related clades. Also, neither of the diagnostic character states proposed by Lopes (1983) in the description of Retrocitomyia nor those suggested by Pape (1996) emerged as autapomorphic for this genus. However, when used in combination, those character states will still be useful for diagnosing this genus.

The sister-group relationship between Duckemyia and Peckiamyia has moderate branch support and is supported by three autapomorphies: (1) facial ridge with dense setosity on lower 0.85 ( Fig. 46B View Figure 46 ), (2) cercal prong bilobed with a pointed tip ( Fig. 40H View Figure 40 ) and (3) juxta squared, with anterior margin even, flat or slightly concave ( Figs 16F View Figure 16 , 35E View Figure 35 ). Of the two genera, only Peckiamyia is supported by multiple autapomorphies of the male terminalia and other body parts as follows: (1) postgenal setulae much longer than genal setulae ( Fig. 47B View Figure 47 ), (2) surstylus with a proximal lobe-shaped expansion, (3) surstylus with stubby setae on proximal half, (4) pregonite with strong proximal setae, (5) vesica three-lobed, whose proximal section has a shallow proximal division giving two joined lobes ( Fig. 35D, E View Figure 35 ) and (6) vesical lateral arms trapezoid ( Fig. 35C, E View Figure 35 ). Duckemyia shows one autapomorphy: vesical lateral arms ribbon-like ( Fig. 16G View Figure 16 ). Dodge (1966) identified similarities in external characters between Peckia and Peckiamyia , but he also mentioned Peckiamyia as having ‘anomalous genitalia’ obscuring its affinities. A close relationship between Peckia and Peckiamyia has not been supported in subsequent studies ( Piwczyński et al., 2014; Buenaventura & Pape, 2015), nor in the present study. A comparison of features of Duckemyia latifrons Kano & Lopes, 1969 to those of potentially close generic relatives with proclinate fronto-orbital setae in males was provided by Kano & Lopes (1969), who erected a separate genus for this species. The proclinate fronto-orbital setae in males were here found to be a homoplasious character state. In the same publication, these authors also noted the bifurcated cercal prong ( Fig. 40H View Figure 40 ) in Duckemyia and Peckiamyia , which is also shared with Retrocitomyia .