Anafroptilum Kluge 2012

Genus Anafroptilum Kluge 2012

(Figs 1–87)

Anafroptilum Kluge 2012: 372.

Type species: Centroptilum kazlauskasi Kluge 1983.

Systematic position and characteristics of Anafroptilum. Systematic position of Anafroptilum is vague: from one hand, it shares some peculiar characters common with Cloeonini sensu Kluge 2016b; from other hand, its patella-tibial suture is characteristic for the taxon Protopatellata, while Cloeonini do not belong to Protopatellata.

Character of Anafroptilum common with Protopatellata. (1) In larva, subimago and imago of both sexes patella-tibial suture is absent on fore legs and present on middle and hind legs (Kluge 2012: Figs 13, 14). This character is plesiomorphic, being the same as in the outgroup, i.e. in the most non-baetid mayflies and in the primitive baetid taxa, Siphlaenigma Penniket 1962 and Palaeocloeon Kluge 1997 (Kluge 1997). Among Baetidae in the narrow sense, i.e. Turbanoculata Kluge 1997, this character is present in the taxon Protopatellata Kluge & Novikova 2011 (= Afroptilinae sensu Kluge 1997). In contrast to this, the taxon Anteropatellata Kluge 1997 (comprising overwhelming majority of Baetidae) is characterized by presence of patella-tibial suture on all legs other than fore legs of male imago and subimago. Exceptions are made only by baetids with highly modified leg structure; unlike them, Anafroptilum has leg structure non-modified, similar to that of Cloeonini sensu Kluge 2016b and many other taxa.

Characters of Anafroptilum common with Cloeonini. The taxon Cloeonini sensu Kluge 2016b includes genera Cloeon Leach 1815 (in narrowest sense), Procloeon Bengtsson 1915, Similicloeon Kluge & Novikova 1992 and related taxa (Kluge 2016b). In contrast to Anafroptilum, all representatives of Cloeonini have patella-tibial suture equally developed on all legs of larva and female, so Cloeonini undoubtedly belong to Anteropatellata (see above). Besides evident symplesiomorphies, Anafroptilum and Cloeonini share the following common characters: (2) Larval labial palp with 3rd segment truncate and 2nd segment non-projected (Figs 16, 78). The same in some other taxa. (3) Larval abdominal segments VIII and IX with spines forming one longitudinal row on each lateral margin; sometimes such spines are present also on some of previous abdominal segments. This character is constant for Cloeonini and not found in any taxa other than Cloeonini and Anafroptilum. Among Anafroptilum, these spines are either constantly present (e.g. in A. kazlauskasi, A. bifurcatum, A. victoriae), or occasionally absent (e.g., in A. album, A. conturbatum) (Lowen & Flannagan 1991). In the two new species from Thailand, these spines are either poorly developed, or absent (see below). (4) Male imaginal gonovectes are fused with penial bridge (Figs 41, 79). Among Protopatellata, the same in the Afrotropical taxon Rhithrocloeoninae (Kluge 2015).

Symplesiomorphies of Anafroptilum, Cloeoninae, some Protopatellata and some other taxa. (5) Larval claw with 2 equal rows of denticles (in contrast to Baetungulata and some other taxa). (6) Fore wing with single marginal intercalaries (in contrast to Baetovectata). (7) In subimago of both sexes either all segments of all tarsi are covered with pointed microlepides, or only proximal part of tarsus is covered with microtrichiae (Fig. 49); blunt microlepides are absent on all tarsomeres (in contrast to Baetungulata). (8) Subimaginal gonostyli developing under larval cuticle are folded in « Cloeon - type » pose (Fig. 43) (in contrast to Baetovectata).

Characters of Anafroptilum of unclear phylogenetic status. (9) Dorsal surface of labrum with irregularly situated setae, without constant pair of submedian setae and without regular latero-distal setal rows (Figs 35, 76).

The same in some Cloeonini and in Centroptilum. (10) Both mandibles with incisor and kinetodontium deeply separated (Figs 13–14, 38–39, 61–62). The same in Centroptilum, selected species of Procloeon and some others.

(11) Both mandibles with dense setae between prostheca and mola (Figs 13–14, 61–63). The same in all Cloeonini, Centroptilum and some others. (12) Maxilla of the « Cloeon - type », i.e. with all 3 canines and 3 dentisetae slender, pointed and bent at the same direction (Figs 17, 77). The same in many other taxa. (13) Glossa and paraglossa of the « Cloeon - type », i.e. subequal in length and width, pointed, paraglossa with no more than one regular row on outer-apical margin (Figs 36, 78). The same in many other taxa. (14) Larval femora without row of stout setae on outer margin and without stout outer-apical setae; outer-apical margin serrate, with sparse thin hairs (Fig. 59). The same in Centroptilum and selected species of Procloeon. (15) Male imaginal gonostylus with 2nd segment thickened apically, 3rd segment petiolate (Figs 41, 79). The same in Centroptilum and Cheleocloeon (Kluge 2016a: Figs 98, 106, 108, 110). In Cloeonini, second segment of gonostylus is also widened apically, and third segment is also petiolate, but smaller. In other respects external genitals of Anafroptilum are highly variable: 1st segment of gonostylus either with characteristic projection on inner side (Fig. 79), or without it (Fig. 41); 2nd segment either arched (Fig. 79), or straight (Fig. 41); median finger-like projection either present (Figs 41, 79), or absent.

Variable characters of Anafroptilum. (16) Hind wings either present, or absent (in A. minor and two new species described below). If present, hind wing is either of the « Baetis -type», i.e. relatively wide, with three longitudinal veins and short costal projection (e.g., in A. bifircatum), or of the « Centroptilum -type», i.e. narrow, with two longitudinal veins and hooked costal projection (e.g., in A. kazlauskasi). (17) Tergalii either asymmetrically widened (Figs 69–75), or narrow and symmetric (Figs 28–34).

Distribution. Amphipacific: Asia (East Palaearctic and Oriental Regions) and Nearctic.