Loew, H. (1858) Bidrag till kannedomen om Afrikas Diptera [part]. Ofvers. K. Vetenskapsakad. Forh. (1857) 14: 337-383. [early 1858.??.??]
Paragus (Pandasyopthalmus) longiventris Loew
Paragini, with the single genus Paragus, is a compact and distinctive group occurring in all continents other than South America and Antarctica. Paragus species are small, slender to moderately robust, with thorax black or with apex of scutellum pale, and abdomen usually extensively red-orange to entirely black. Paragus has postpronotum bare, antenna short, anterior anepisternum bare, abdomen parallel-side, face yellow in background colour, metaepisternum bare, scutum black laterally, at most with a poorly defined yellow polinose vitta, and metasternum bare.
The subgenus Pandasyopthalmus sensu Vujic et al. (2008) has eye uniformly pilose; scutum shining, finely punctured, without pollinose submedial vittae; scutellum with rounded posterior margin, without conspicuous teeth or bristles; abdomen elongate, usually narrowed between terga 2 and 3; terga 1–2 fused; terga 3–5 usually not fused, connection between terga 2 and 3 movable; connections between terga 3–5 immovable; male genitalia: minis small, lateral arms of minis long; aedeagus ‘amphora-like’.
Pandasyopthalmus is divided in two species groups: jozanus and tibialis groups. P. longiventris belongs to the tibialis group, whose species have face with distinct facial tubercle and with dark facial stripe in females; basoflagellomere about three times as long as pedicel; spurious vein extending beyond or to the meeting point of vein M1 with vein DM; male genitalia: ejaculatory apodeme narrow and distally with large umbrella-like fringe; lateral lobe of aedeagus reduced; postgonite much more protruded anteriorly than aedeagus; aedeagal apodeme with well-developed lateral arms; aedeagus with small, arm-like lateral projections; hypandrium usually with characteristic lateral projections.
Head: Face yellow with medial black vitta, black on mouth margin, yellow pilose; gena black; frontal triangle yellow, yellow pilose; vertical triangle black, black pilose; antenna dark brown, basoflagellomere elongate, arista submedial; dichoptic, eyes separated by facet width, eye scarcely pilose; occiput black, silver pollinose, withish-yellow pilose.
Thorax: Scutum and scutellum shiny black, punctate, white pilose; subscutellar fringe complete. Pleuron black, with long white pile; metasternum bare. Wing: Wing membrane hyaline, microtrichose with broad bare areas basally. Alula broad, bare basally with few microtrichia apically. Legs: Entirely yellow except coxae and trochanter black; profemur black on basal 1/3, mesofemur black on basal 1/2 and metafemur black except apical 1/4 yellow; metatibia with subapical black ring; metabasitarsomere slightly broadened and dark basally.
Abdomen: elongate, subpetiolate, black, punctuate; narrowed between terga 2 and 3; terga 1–2 fused; terga 3–5 usually not fused, connection between terga 2 and 3 movable; connections between terga 3–5 immovable.
Similar to male except fons entirely black and medial black facial vitta broader.
GenBank accession number for this species are: protein-coding COI gene (AY174463; AY476859), and rRNA 28S gene (AY476887).
Paragus is the only genus of the tribe Paragini and its phylogenetic position is uncertain. Dusek and Laska (1967) did not comment on the sister group of Paragus but mentioned that the genera Didea and Paragus share some characters of the adult morphology and male genitalia and they placed Paragini as one of the first branches of Syrphinae, commonly called basal clades. Shatalkin (1975) said that Paragini was a tribe aberrant in relation to all other tribes of the subfamily based on characters of the male genitalia. Rotheray and Gilbert (1989) using larval characters, resolved the genus as sister group of the tribe Pipizini. In 1999, Rotheray and Gilbert reported Paragus as sister group of the clade Eupeodes + Scaeva + Ischiodon.
Ståhls et al. (2003) using morphological and molecular characters resolved Paragus as sister group of the genera Chrysotoxum and Syrphus. Hippa and Ståhls (2005), based only on adult morphological cahracters, found a similar conclusion: Paragus as sister group of Chrysotoxum, Syrphus, Toxomerus and Sphaerophoria. Mengual et al. (2008) using only molecules, resolved Paragini as sister group of Allobaccha, a position never suggested before
Although there are recent studies about the intrageneric classification of Paragus (Kassebeer, 1999a,b, 2001; Rojo et al., 2006; Vujic et al., 2008), the placement of this tribe in the subfamily Syrphinae is unresolved as previous results disagree. Currently there are four subgenera based on the study by Vujic et al. (2008): Paragus s. str., Serratoparagus, Afroparagus and Pandasyopthalmus (the latest with two species groups, tibialis and jozanus groups).
Larvae of P. longiventris have ben reported feeding on aphids (Aphididae) of teh genera Aloephagus, Aphis, Brachycaudus, Dysaphis, Hysteroneura, Melanaphis, Pentalonia, Rhopalosiphum, and Sitobion (Rojo et al. 2003).
Species described from South Africa, but it is widespread Afrotropial Region, including Madagascar, Comoro Islands, São Tomé and South Yemen.