Paracantha Coquillett

Norrbom, Allen L., Sutton, Bruce D., Steck, Gary J. & Monzón, José, 2010, New genera, species and host plant records of Nearctic and Neotropical Tephritidae (Diptera) 2398, Zootaxa 2398, pp. 1-65 : 29-31

Paracantha Coquillett

Paracantha Coquillett 1899 (type species Trypeta culta Wiedemann , by original designation).

Neorhabdochaeta Malloch 1941 (type species N. anduzei Malloch , by original designation, = P. ruficallosa Hering ); Norrbom et al. (1999: 180) (synonymy).

Laksyetsa Foote 1978 (type species L. trinotata Foote , by original designation). New synonymy.

The monotypic genus Laksyetsa Foote is here considered a subjective junior synonym of Paracantha Coquillett , as is Neorhabdochaeta Malloch , which was placed in synonymy with Paracantha by Norrbom et al. (1999).

Paracantha occurs from Canada to Argentina and Chile and includes 11 described and at least two undescribed species, which breed in flowerheads of various Asteraceae , including thistles, Cirsium spp. (Cardueae) , Dahlia (Coreopsideae) , Calea (Neurolaeneae) , and sunflowers and related genera, such as Borrichia , Helianthus , and Viguiera (Heliantheae) ( Foote et al. 1993, Prado et al. 2002).

Paracantha is most closely related to Rachiptera Bigot , as indicated by the following two synapomorphies: Face, lunule, and frons ( Figs. 57, 59–60, 102, 105) shiny yellow, mostly nonmicrotrichose, with blackish spots, including parafacial spot at level of base of antenna and 1–4 spots on face; eyes ( Fig. 57) with two rows of four irregular red spots, sometimes narrowly connected, on green background (pattern often faded or absent after death). Some Schistopterini and other Eutretini have patterned eyes, but the markings are different

(e.g., in many species of Eutreta , the eye has three green medial stripes on a red background).

Although the type species of Neorhabdochaeta and Laksyetsa each have a number of distinctive characters, it is questionable whether the remaining species of Paracantha form a monophyletic group without including them. An undescribed species (n. sp. B) most closely related to P. ruficallosa shares some, but not all of the apomorphic characters of P. ruficallosa . At least one apomorphy (anterior orbital seta anterior to posterior frontal seta) supports the hypothesis of closer relationship of the species exclusive of P. trinotata ,

whereas another (bulla in cell r 4+5 with dark brown medial spot) suggests that P. trinotata is more closely related to the species exclusive of P. ruficallosa and n. sp. B.

The following synapomorphies support the monophyly of Paracantha (including P. trinotata ):

1) Frons ( Fig. 57) usually with three or more pairs of orbital setae, all of which are white (2–3 in P. trinotata , posterior seta occasionally brown; plesiomorphic state (as in Rachiptera and most other Tephritinae )—2 setae, at least anterior seta dark). A few Dithrycini and an undescribed species of Dictyotrypeta have three setae, with the anterior seta brown, but the above combination is unique to Paracantha .

2) Scutellum ( Figs. 58, 103) with three or more pairs of erect white setae in a nearly pentagonal arrangement, the more proximal two pairs located on the disc distinctly medial to the basal pair of normal marginal setae. The proximal pair are sometimes smaller than the two more apical pairs, which are usually subequal. Many species of Schistopterini ( Freidberg 2002) as well as some Noeetini have erect scutellar setae, but their number, size, and arrangement vary. The proximal two pairs, if present, are often smaller than the subapical setae or are near the margin or irregularly arranged on the disc, whereas they are consistent in position in Paracantha . The presence of erect setae may be a synapomorphy at some higher level, but their number and location on the disc is a synapomorphy of Paracantha species. Rachiptera do not have erect setae on the scutellum.

3) Wing ( Figs. 50–53) with three bullae, one in cell r 2+3 well basal to r-m, one in cell dm slightly basal to r-m (usually poorly differentiated in P. trinotata ), and one in cell r 4+5 anterior to dm-cu. They are weak or sometimes absent in P. ruficallosa Hering. This combination of bullae is a synapomorphy of Paracantha species. Various Tephritinae have a bulla in cell r 4+5, and at least some species of Rhabdochaeta and Schistopterum have bullae in cells r 2+3, dm and r 4+5, but at least in the species we have examined they are closer together than in Paracantha , with the one in r 4+5 aligned with or proximal to dm-cu. Other Schistopterini , such as Rhochmopterum Speiser and Bactropota Bezzi , lack them, as do Rachiptera species. This character may also have some phylogenetic significance at a higher level, but the position of the bullae is a probable synapomorphy for Paracantha .

4) Face with 1–4 dark brown spots, including medial spot near midheight and often 2–3 spots on ventral margin ( Fig. 57). In Rachiptera ( Fig. 60) the face has 2 or 4 dark brown spots, but lacks a medial spot near midheight.

5) The egg of P. trinotata is similar to those of the four species for which the egg has been described previously, P.culta (Wiedemann) , P. cultaris (Coquillett) , P.forficula Benjamin , and P. gentilis Hering ( Benjamin 1934, Cavender & Goeden 1984, Headrick & Goeden 1990), in having an elongate, slender lobe on the micropyle end. The lobe is absent in Rachiptera limbata Bigot ( Frías 2008) suggesting that it is a synapomorphy of Paracantha species , although it should also be noted that clearly unrelated tephritid species such as Aciurina ferruginea (Doane) and some species of Chaetorellia and Craspedoxantha have a similar elongate lobe on the egg ( Tauber & Tauber 1967, White & Marquardt 1989, Freidberg 1985).

6) Paracantha species , except P. trinotata , have a radiate wing pattern, with at least some of the rays broad and orange with dark borders ( Figs. 50–52). In Schistopterini and other Eutretini (some Dictyotrypeta spp. ) that have radiate patterns the rays are generally narrow, and are entirely dark or may contain hyaline spots. Rachiptera species have reticulate wings, except in R. parallela (Hendel) the anterior margin has short, irregular rays ( Fig. 105). It is unclear whether the radiate pattern in Paracantha is a synapomorphy for the species other than trinotata , or for all of them if the pattern in P. trinotata was derived from it. The hyaline areas between the rays vary considerably in size within Paracantha and in some species (e.g., P. multipuncta Malloch ( Fig. 51)) are relatively small, especially in cells r 2+3, r 4+5 and m, intermediate between P. trinotata ( Fig. 53) and other Paracantha ( Figs. 50, 52), suggesting the latter hypothesis.