Somatiidae Hendel, 1935

Lonsdale, Owen, 2020, Family groups of Diopsoidea and Nerioidea (Diptera: Schizophora) - Definition, history and relationships, Zootaxa 4735 (1), pp. 1-177 : 30-32

Somatiidae Hendel, 1935

( Figs 65–66 , 71–80 , 401 )

Type genus: Somatia Schiner 1868: 245 , by Hendel (1935: 56). Type species of genus: Somatia xanthomelas Schiner, 1868: 246 [= Tephritis aestiva Fabricius, 1805: 318 ], by original designation.

Somatiidae is a small family of seven morphologically similar Neotropical species in the single genus Somatia , with only S. aestiva (F.) encountered with relative frequency. The genus was first keyed and then catalogued by Steyskal (1968 c, 1970a), and later reviewed by Lonsdale & McAlpine (2010).

Biology. Marshall (2006) first observed adult Somatia feeding on a dead caterpillar. Species have also been observed at the extrafloral nectaries of several plants. Carvalho-Filho (2017) found numerous specimens feeding on the underside of Solanum stramonifolium Jacq. (Solanaceae) leaves, as well as one specimen “licking the calyx” of Pleonotoma jasminifolia (Kunth) Miers (Bignoniaceae) . The author speculated that extra-floral nectaries may explain the presence of Somatia specimens on other plants mentioned in the literature, including legumes ( Marshall, 2012). Hespenheide (1985) also noted that Somatia “are common visitors at extrafloral nectaries of other plants”, and Grimaldi (2016) found Somatia at nectaries of Passiflora (Passifloraceae) .

Immature stages. Unknown.

Adult Diagnosis. Relatively small to medium-sized yellow and black species with stout thorax and broad, downturned abdomen. Antenna elbowed, first flagellomere elongate; pedicel with dorsal seam; arista bipectinate. Frons produced anteriorly as flat, widening plate. Outer vertical, fronto-orbital, ocellar and sometimes inner vertical setae absent; vibrissa small; postocellars convergent (divergent in other Diopsoidea). Postpronotal, proepisternal and katepisternal setae absent; notal setulae long and dense; one dorsocentral, one prescutellar acrostichal and one anepisternal seta; 2–3 pairs of scutellar setae on small tubercles; notopleural setae both closely set posteriorly. Mid tibia with three ventroapical setae. Back of head with strong dorsal semicircular carina and pronotum produced as short “neck”. Transverse suture complete. Suture between T1 and T2 medially crenulated. Precoxal bridge absent, postmetacoxal bridge present. Wing with alula and anal lobe weak; cells bm and cup long; costa with sc break; sc complete.

Adult Definition. Relatively small to medium-sized flies with a stout, bulging thorax and narrow “neck” (=pronotal collar) ( Figs 71–77 ); body length 3.5–5.2mm. Colour mostly yellow with contrasting black pattern, but S. lanei Papavero mostly dark; setae and setulae yellow with setae sometimes darker and abdominal setulae on brown pattern sometimes also darker.

Chaetotaxy: 0–1 inner vertical; 0 outer vertical; 0 fronto-orbital; 0 ocellar; 1 postocellar (convergent); vibrissa small. 0 presutural intra-alars; 0 postpronotal; 2 posterior notopleurals (likely representing anterior and posterior setae); 2 posterior supra-alar (one sometimes duplicated on one or both sides); 1 posterior intra-alar; 1 dorsocentral; 1 acrostichal; 2–3 scutellars on minute tubercle; 0 proepisternal; 1 anepisternal; 0 katepisternal. Pedicel with small marginal setae including longer dorsal and ventral seta; frons densely setulose laterally (inclinate inner row and erect outer row, becoming more scattered anteriorly and posteriorly) and with broad, shining medial region; postocular setae short and in single row laterally, becoming longer, more numerous and scattered dorsally; back of head with longer ventromarginal setae. Setulae long, straight and dense on scutum and abdominal tergites, sometimes difficult to distinguish from short setae; scutellum with similar setulae that are paler, denser and shorter; pleuron with short to long erect setulae mostly restricted to anepisternum and katepisternum; posterior spiracle with several outstanding setae near posterior margin. Body glabrous with microsetulae restricted to metanotum and portions of pleuron, including katepimeron. Fore tibia sometimes with slightly pronounced ventroapical setula; mid tibia with three ventroapical setae.

Head. Antenna elbowed, first flagellomere flat and relatively broad, length more than twice width (extending to lower margin of face); pedicel with dorsal seam; arista bipectinate. Frons produced anteriorly as flat widening plate covering base of antenna; ocelli near vertex. Face with shallow, wide ridge below antennal bases. Back of head flat above foramen with prominent semicircular carina (setulose dorsomedially). Clypeus broad, well-developed; palpus subcylindrical; labium with long apical processes and one or two pairs of subapical setae.

Thorax. Large and bulging, including scutellum; with narrow pronotal collar; lateral corners of scutellum extended along margin of scutum as carinae. Transverse suture complete. Greater ampulla absent. Presternum vestigial. Anterior spiracle slit-like, oblique, in crease between bulging anepisternum and postpronotum. Katatergite flat. Metathorax with narrow, shallow subcylindrical extension meeting abdomen. Coxopleural streak present. Precoxal bridge absent; prosternum broad, flat along raised posterior margin and with shallow anteromedial point; postmetacoxal bridge high, well-developed.

Wing. ( Fig. 401 ) Wing slightly narrowed with anal lobe and alula reduced. Basal stripe, variably developed medial stripe and anterior and anterodistal margins dark brown. R 2+3 and M 1 convergent apically. Apical section of M 4 present or absent; M 4 and CuA+CuP not reaching wing margin. Cells bm and cup long, exceeding apex of R s; costa with sc break; sc complete. Calypter almost linear, hairs of moderate length.

Legs. Slender, shifted forward, with apices of coxae approximate; base of elongate fore coxa dorsally removed to ventrolateral margin of collar.

Abdomen. Dorsum broadly dome-like with T2 largest; terminalia short, stout, much narrower and held under apex of abdomen; sternites much narrower, forming narrow medial line. T1 and T2 fused with suture complete, raised and with minute crenulations along posteromedial surface ( Fig. 77 , arrow). T2 with broad anterolateral bulge. Spiracles 1–6 in membrane; 7 th spiracle in tergite ( Fig. 78 ). Following description of terminalia based on dissections of S. aestiva .

Male genitalia. ( Figs 78–80 ) S6 offset, nearly symmetrical. S7+8 dorsal, band-like, encompassing spiracles, slightly longer on left side. Epandrium semicircular and band-like, lateral margins meeting bases of asymmetrical surstyli that are sinuate and ventrally approximate (left surstylus treated as “postgonite” in Lonsdale & McAlpine (2010)). Cerci broad, meeting medially, appearing as ventral setose bands on inflated, membranous perianal region; sclerotized band in membrane below cerci. Hypandrium, epiphallus, and gonites absent. Phallapodeme free within abdomen, articulating with fused basiphallus + distiphallus. Distiphallus, long, black, ribbon-like, partially coiled and exposed. Ejaculatory apodeme large with fan-like blade grading into basally narrow stem; sperm pump with large membranous fringe encompassing base of apodeme.

Female genitalia. ( Figs 65–66 ) T7 and S7 fused into stout oviscape enclosing spiracles. T8 short and wide, wrapping around segment laterally; S8 subrectangular, wider than long. T10, S10 and cercus short, wide and broadly rounded. Spermatheca slightly more than two times longer than wide, subcylindrical with rounded ends, dark pigment and numerous minute papillae; ducts relatively short, not pigmented apically. Ventral receptacle short, flagellate.

Figures

FIGURES 62–70. Figs 62–64: Nothybus biguttatus Wulp (Nothybidae), female abdomen; 62: segment 7 to cercus, ventral; 63: same, dorsal; 64: internal genitalia. Figs 65–66: Somatia aestiva (Fabricius), female abdomen; 65: segment 7 to cerci; 66: internal genitalia. Figs 67–70: Gobrya sp., female abdomen; 67: segment 6 to cerci, dorsal; 68: same, right lateral; 69: same, ventral; 70: spermathecae.

FIGURES 71–77. Somatia aestiva (Fabricius) (Somatiidae); 71: female dorsal; 72: same, lateral; 73: head, anterolateral; 74: female head, anterior; 75: same, dorsal; 76: head, posterior; 77: lateral.

FIGURES 78–81. Somatia aestiva (Fabricius) (Somatiidae), male abdomen; 78: ventral; 79: terminalia, left lateral; 80: same, posterior; 81: ejaculatory apodeme.

FIGURES 395–402. Wings; 395: Belobackenbardia cornicula Shatalkin (Psilidae), female paratype; 396: Chyliza notata Loew (Psilidae); 397: Psila hennigi (Thompson & Pont) (Psilidae); 398: Loxocera cylindrica Say (Psilidae); 399: Nothybus longicollis (Walker) (Nothybidae); 400: N. biguttatus Wulp; 401: Somatia aestiva (Fabricius) (Somatiidae); 402: Gobrya sp. (Gobryidae).