Paraclius Loew

SCOTT E. BROOKS, 2005, Systematics and phylogeny of Dolichopodinae (Diptera: Dolichopodidae), Zootaxa 857, pp. 1-158 : 83-88

Genus Paraclius Loew

( Fig. 20 A–E)

Paraclius Loew, 1864: 97 . Type species: Pelastoneurus arcuatus Loew [Neotropical], designation by Coquillett, 1910: 583. Erroneously treated as an emendation of Paracleius Bigot (a synonym Pelastoneurus Loew, 1861 ) in Foote et al. (1965) and elsewhere (see Brooks et al. (2002) and Cumming & Vockeroth (2003)).

Leptocorypha Aldrich, 1896: 315 . Type species: Leptocorypha pavo Aldrich [Neotropical], by monotypy. Synonymized by Robinson (1970b).

Leptorhethum, Parent, 1934a , not Aldrich, 1893, misid. listed by Bickel and Dyte (1989).

Recognition. Paraclius , as currently recognized, is a polyphyletic assemblage of species that can be recognized by the following combination of characters: arista bare to strongly pubescent, not plumose (i.e. with dorsal and ventral hairs longer than lateral hairs), rarely with apical lamella in male; clypeus flat or weakly produced, distinctly shorter than face in male, lower margin usually straight and ending above lower eye margin, rarely rounded below and extending beyond lower eye margin; wing vein M beyond crossvein dm­cu with strong anterior bend near or beyond middle, strongly convergent with R4+5 and usually arcuate; hind coxa with strong lateral seta usually near apex; mid and hind femur usually with 1 anterior to anterodorsal preapical seta; hind basitarsis without dorsal setae. Paraclius sensu stricto (the P. arcuatus lineage), can be distinguished by the following combination of characters: face of male very narrow and strongly converging below; distal section of M beyond crossvein dm­cu with strong, arcuate anterior bend beyond middle; hind femur wide and flat with anterior preapical near apex, hypopygium with elongate anterior apicoventral epandrial seta and distinctive elongate ventral surstylus, cercus lacking basolateral tail.

Description (based on P. arcuatus lineage). Head: Vertex flat to weakly excavated, 1 pair of strong vertical setae, stronger than postverticals. Frons about 2.7–2.9 x wider than high, sides weakly to distinctly convergent below. Face and clypeus very narrow in male, broad in female. Face with sides strongly convergent below in male, sides subparallel or convergent below in female. Clypeus flat and often slightly recessed to weakly produced, occasionally strongly bulging in female, lower margin straight, ending above lower eye margin. Palp small in male slightly larger in female, ovoid, with weak hairs on outer surface, distinct apical seta present. Antenna: Scape short, subconical, with well­developed acute medioventral process and weaker acute process ventrally; pedicel short; first flagellomere ovoid to subtriangular, shorter in female; arista dorsal, near base, 2­segmented, distal segment strongly pubescent. Lower postocular setae flattened, lowermost seta usually stronger. Postvertical setae slightly to distinctly stronger than uppermost pair of postoculars.

Thorax: Acrostichals biserial; 5 dorsocentrals, fourth pair aligned or slightly offset medially; 1 strong outer posthumeral, 1 weak to indistinct inner posthumeral; 2 notopleurals; 1 presutural; 1 sutural; 2 supraalars; 1 postalar. Upper and lower part of propleuron with sparse fine hairs, upper part of propleuron with 1–3 somewhat stronger setae immediately in front of anterior spiracle; lower part of propleuron with 1 strong prothoracic seta; pleural surface in front of posterior spiracle bare; metepisternum with several fine hairs. Scutellum with 1 strong inner seta and 1 small outer seta on lateral margin, posterior margin sometimes with a pair of weak setae (e.g., P. arcuatus ).

Legs: Pulvilli developed normally on all legs. Foreleg: Femur often with 1–2 distinct preapicals anteroventrally and posteroventrally. Midleg: Femur somewhat laterally flattened and wide, with 1 anterior preapical seta, sometimes with 1 weak anteroventral preapical seta or a series of progressively longer setae towards apex, terminal posteroventral seta often well­developed. Hindleg: Coxa with strong lateral seta near apex; femur laterally flattened and wide, 1 anterior preapical seta relatively close to apex, 1 welldeveloped to indistinct anteroventral preapical seta and/or series of progressively longer setae towards apex; tibia of male with thickened spinules on ctenidia; basitarsus shorter than second tarsomere, with 2–3 ventral setae; male with small dentiform posterobasal process.

Wing: Brownish or grayish. R2+3 straight; R4+5 straight or with weak posterior curve in apical part; distal section of M beyond crossvein dm­cu with strong anterior bend beyond middle, arcuate, ending well before wing apex, strongly convergent with R4+5; crossvein dm­cu shorter than distal section of CuA1.

Abdomen: Subconical. Male: T6 bare (e.g., P. arcuatus ), or with a few setae along lateral margin (e.g., P. pumilio Loew , Paraclius sp. 1); S2 weakly sclerotized, sometimes divided medially; S3 emarginate and membranous posteromedially or divided; S4 mainly membranous, sclerotized anteriorly and laterally; S5 mainly membranous anteriorly, weakly sclerotized posteriorly and continous with S6 forming a plate­like sclerite; segment 7 forming well­developed peduncle; S8 subovoid, setose on posterior half. Hypopygium ( Fig. 20 A–C) somewhat slender in lateral view, subequal in height to segment 7. Epandrium ovoid in lateral view, about 2.3–2.7 x longer than high, with lateral ridge on apical half forming an acute apical projection directly above apicoventral epandrial setae; foramen positioned anterolaterally, well­separated from base of cerci; basiventral epandrial lobe not developed, small basiventral epandrial seta present along ventral epandrial margin; apicoventral epandrial lobe not developed, 2 apicoventral epandrial setae present, anterior seta elongate, posterior seta elongate or relatively short. Surstylus bilobed. Ventral lobe elongate slender and digitiform with stout modified apical seta. Dorsal lobe broad basally, with 2 thick dorsal setae, apex blunt or acute. Postgonite with anteroventral portion weakly sclerotized; posterodorsal portion well­developed, simple, digitiform. Undivided proctiger brush sometimes present (e.g., P. arcuatus Fig. 20 B). Cercus ovoid to subtriangular and weakly pointed apically, sometimes with elongate lateral setae. Hypandrium elongate, trough­shaped, with weak connection to epandrium basiventrally, free laterally, apex bifurcate, lateral margin with 1–2 dentiform or knob­like preapical projections, base of hypandrium projecting up inside epandrial capsule, cradling phallus ( Fig. 20 B); hypandrial apodeme absent or not distinctly separated from basal sclerite of sperm pump; hypandrial arms connected to base of hypandrium. Sperm pump relatively large; ejaculatory apodeme elongate, laterally flattened, sometimes weakly sclerotized; basal sclerite of sperm pump well­developed, V­shaped to broadly U­shaped in dorsal view. Phallus long, slender, with small bumps or spinules, apical part with dentiform or rounded projections. Female ( Fig. 20 D,E): T6, S6 and S7 undivided, T7 undivided, or weakly divided medially; T8 and S8 divided medially, tergite and sternite fused anterolaterally forming a narrow sclerite ( Fig. 20 E). T10 divided medially into hemitergites each bearing 5 spines, innermost pair sometimes slightly offset, spines rounded and somewhat flattened apically.

Geographical Distribution. Paraclius occurs in all zoogeographical regions, but is most diverse in the Neotropics. The Paraclius arcuatus lineage is known from the New World.

Phylogenetic Relationships. As indicated by the cladistic analysis, Paraclius is a polyphyletic group within the clade including Cheiromyia , Stenopygium , Pelastoneurus , Platyopsis , Tachytrechus and Metaparaclius . Much additional work is needed to resolve the phylogenetic relationships of Paraclius on a worldwide basis. At present the only phylogenetically meaningful generic concept includes the lineage closely related to the generic type, P. arcuatus (e.g., P. p u m i l i o, Paraclius sp. 1), as diagnosed and described above. Based on the material examined in this study there appear to be several recognizable species groups within Paraclius sensu lato and it is likely that additional genera will have to be established to accommodate these lineages; however, this is beyond the scope of my study. Until all the species of this genus can be studied in more detail, Paraclius will serve as a holding genus, like Hercostomus .

In addition to the P. arcuatus lineage, I have seen two additional New World species groups of Paraclius . The first group is primarily characterized by the possession of a basolateral tail on the male cercus and was recently discussed by Bickel & Sinclair (1997). This group includes P. alternans , P. claviculatus Loew , P. desenderi Bickel & Sinclair , P. difficilis Becker , P. discifer Aldrich , P. hebes Van Duzee and P. filifer Aldrich , which were examined in this study, as well as P. affinis Robinson , P. propinquus Wheeler , P. maritimus Va n Duzee, P. flagellatus (Harmston) for which specimens were not examined. This group is further characterized by a greatly enlarged and somewhat spherical sperm pump and a pair of proctiger brushes similar to those observed in Pelastoneurus (absent in Paraclius filifer ). Paraclius hybridus Melander and P. quadrinotatus Aldrich apparently belong to this group, but lack the tail on the cercus. Paraclius sarcionoides Robinson may also be related to this group but lacks an enlarged sperm pump. This species is also unusual in that it has a spiny, divided phallus and a very well­developed hypandrial apodeme. Paraclius arcuatus possesses an undivided, haired proctiger lobe similar to the proctiger brushes of this species group, but this lobe is absent in the other examined members of the P. arcuatus lineage.

The other New World species group includes P. brevicornis Van Duzee , P. dominicus Robinson , P. flavicauda Van Duzee , P. floridensis Robinson , P. longicornis Van Duzee , P. ovatus Van Duzee and P. venustus . This group is characterized by the possession of a ringshaped sclerite surrounding the base of the phallus. This sclerite appears to be an extension of the postgonite, as illustrated by P. flavicauda , where the anteroventral portion of the postgonite and ring­shaped sclerite are fused. This connection is absent in the other species. Paraclius megalocerus seems to be close to this group, but lacks the characteristic basal phallic ring. Most of the species in this group also possess a greatly enlarged sperm pump, similar to the P. alternans group discussed above (sperm pump not enlarged in P. ovatus ), but lack proctiger brushes. The male genitalia of species in this group show an overall similarity to that of Cheiromyia ; however, at present I have not found a synapomorphy to support this relationship.

All of the Oriental species examined (i.e. P. abbreviatus , P. emeiensis , P. pilosellus and P. luculentus ) share a patch of setae on the posterolateral margin of the metepimeron (character 16:1). The latter three species, plus “ Polymedon ” inopinatus, form a distinctive species group characterized by the possession of finely branched setae on the apicoventral epandrial lobe, large, dark cerci, and a complex, eversible, apicodorsal epandrial sac. The following species (not examined) also seem referable to this group: P. acutatus Yang & Li , P. curvispinus Yang & Saigusa , P. longicornutus Yang & Saigusa , P. menglunensis Yang & Grootaert , P. xanthocerus Yang & Grootaert , P. yunnanus Yang. This Oriental species group appears to be related to a species group including Metaparaclius australiensis and Paraclius neglectus (see “Phylogenetic relationships” under the generic treatment of Metaparaclius ).

Remarks. Aldrich (1902) recorded a “light variety” of P. arcuatus from Grenada in which the hind legs are mainly yellow. I have examined a male and several females from this series and compared them with the female holotype of P. arcuatus as well as other identified specimens of P. arcuatus showing the typical leg color, i.e. with the hind femur dark on distal half and hind tibia dark brown. The pale­legged specimens from Grenada belong to a separate, apparently undescribed species ( Paraclius sp. 1). Genitalic differences are seen in the structure of the hypandrium, apex of the phallus and shape of the dorsal surstylar lobe. Like P. pumilio , the male of Paraclius sp. 1 lacks the hairy undivided apical proctiger lobe, present in P. arcuatus ( Fig. 20 B). These two species also possess lateroventral setae on abdominal T6, which represents a rare exception to the dolichopodine groundplan in which T6 is bare.

The cradle­like extension of the hypandrium ( Fig. 20 B) noted in the description of the P. arcuatus lineage is potentially an informative character that requires further study. This feature is also shared by the P. alternan s species group; but had to be excluded from the analysis due to problems with apparent intermediates and cases of uncertain homology encountered while attempting to code and score this character across the range of exemplars.

Material Examined. Paraclius arcuatus (Loew) , [NT]: Ψ holotype ( MCZ); 1ɗ, 7Ψ ( USNM); 2ɗ ( CAS); Paraclius abbreviatus Becker , [OR]: 1ɗ, 1Ψ ( BMNH); Paraclius alternans (Loew) , [NE]: 2ɗ, 1Ψ ( CAS); 2ɗ, 1Ψ ( CNC); Paraclius brevicornis Van Duzee , [NT]: 2ɗ paratypes, 1Ψ paratype ( CAS); Paraclius claviculatus (Van Duzee) , [NE,?NT]: 1ɗ ( CAS); Paraclius desenderi Bickel & Sinclair , [NT]: 1ɗ paratype, 1Ψ paratype ( CAS); Paraclius discifer Aldrich , [NT]: 2ɗ, 2Ψ ( USNM); Paraclius difficilus Becker , [NT]: 1ɗ ( USNM); Paraclius dominicus Robinson , [NT]: 3ɗ paratypes, 2Ψ paratypes ( USNM); Paraclius emeiensis Yang & Saigusa , [OR]: 1ɗ paratype, 1Ψ paratype ( ISNB); Paraclius filifer Aldrich , [NE, NT]: 5ɗ, 2Ψ ( CAS); Paraclius flavicauda Van Duzee , [NT]: 1ɗ ( CAS); Paraclius floridensis Robinson , [NE]: 1ɗ ( CAS); Paraclius hebes Van Duzee , [NT]: 1ɗ paratype, 1ɗ, 1Ψ ( CAS); Paraclius hybridus Melander , [NE]: 3ɗ, 1Ψ ( CAS); Paraclius longicornis Van Duzee , [NT]: 2ɗ paratypes, 1Ψ paratype ( CAS); Paraclius luculentus Parent , [OR]: 1ɗ, 1Ψ ( BMNH); Paraclius megalocerus Robinson , [NT]: 2ɗ paratypes, 2Ψ paratypes ( USNM); Paraclius microproctus Parent , [AF]: ɗ holotype ( MRAC); Paraclius neglectus Becker , [AU]: 4ɗ, 2Ψ ( CNC); Paraclius ovatus Van Duzee , [NE,?NT]: 4ɗ ( CAS); Paraclius pilosellus Becker , [OR]: 1ɗ syntype, 2Ψ syntypes ( DEI); Paraclius pumilio Loew , [NE, NT]: 3ɗ, 2Ψ ( CAS); Paraclius quadrinotatus Aldrich , [NE]: 3ɗ, 1Ψ ( CAS); Paraclius sarcionoides Robinson , [NT]: 2ɗ paratypes, 2Ψ paratypes ( USNM); Paraclius solivagus Lamb , [AF]: 2ɗ, 1Ψ (LEM); Paraclius venustus Aldrich , [NT]: 1ɗ, 1Ψ ( CAS); Paraclius sp. 1, [NT, Grenada]: 1ɗ, 1Ψ ( BMNH); 2Ψ ( USNM); 1Ψ ( CAS); “ Polymedon ” inopinatus Parent, [OR]: 2ɗ, 2Ψ ( ISNB).

Figures

FIGURE 20. Paraclius arcuatus: (A) Male genitalia, left lateral view (external); (B) Male genitalia, left lateral view (internal); (C) Male genitalia, ventral view (postgonite, surstylus and cerci not shown); (D) Female genitalia, dorsal view; (E) Female genitalia, left lateral view.