Anafroptilum Kluge 2012

Kluge, Nikita J. & Novikova, Eugenia A., 2017, Occurrence of Anafroptilum Kluge 2012 (Ephemeroptera: Baetidae) in Oriental Region, Zootaxa 4282 (3), pp. 453-472 : 454-461

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.

Figures

FIGURE 78. Anafroptilum odontostylus sp. n., labium, ventral view (left) and dorsal view (right). Abbreviation: mr, median row of setae of glossa.

FIGURES 1 – 8. Anafroptilum orthostylus sp. n., larvae. 1 – 3, male larva: lateral, dorsal and ventral view; 4 – 8, eXuviae of last instar larvae: 4, left half of pronotum and mesonotum; 5 – 8, abdominal terga (left) and sterna (right): 5 – 6, males; 7 – 8, females (5, holotype). Abbreviations: I – X, abdominal segments I – X.

FIGURES 9 – 18. Anafroptilum orthostylus sp. n., larvae. 9, tenth abdominal segment and caudalii; 10, enlarged portion of cerci; 11, portion of cercus of another specimen; 12, labrum; 13 – 15, left and right mandibles; 16, labium; 17, maXilla; 18, claw (9 – 10 and 12 – 15, holotype). Abbreviations: al, apical lamella of molar process; dmp, distal molar projection.

FIGURES 19 – 27. Anafroptilum orthostylus sp. n., eXuviae of larval abdomen. 19, median part of tergum IV; 20 – 23, posterior margin of terga V, VI, VII and IX; 24 – 26, posterior margin of sterna V, VIII and sternum IX of female; 27, sternum IX of male with protogonostyli (20 – 22, 27, holotype). Arrow shows paired submedian pore near posterior margin of tergum IX; abbreviations: sV – sIX, sterna V – IX; tIV – tIX, terga IV – IX.

FIGURES 28 – 36. Anafroptilum orthostylus sp. n., larvae. 28 – 34, tergalii I – VII; 35, labrum and clypeus; 36, labium, ventral view (left) and dorsal view (right). Abbreviation: mr, median row of setae of glossa.

FIGURES 37 – 43. Anafroptilum orthostylus sp. n. 37, part of eXuviae of larval head with labrum, bases of antennae and frontal suture; 38 – 39, incisor, kinetodontium and prostheca of left and right mandibles, view from base of mandible; 40, paraproct; 41, genitals of male imago (on the left half, gonovectal muscles and hidden part of penis shown by interrupted lines, gonostylar muscle not shown; at right half gonostylar muscle shown by interrupted lines; median styligeral muscle shown by interrupted lines, areas of anterior attachment of median paraproctal muscles shown by dotted lines); 42, eXuviae of gonostyli of subimago; 43, larval protogonostyli and subimaginal gonostyli developing under larval cuticle (40, 42, holotype). Abbreviations: gs 1, gs 2, gs 3, segments of gonostylus; in, incisor; kd, kinetodontoum; m. IX-X, areas of anterior attachment of median paraproctal muscles (i. e., muscles going from sternum IX to common base of paraprocts); prs, prostheca; usg, unistyliger.

FIGURES 44 – 51. Anafroptilum orthostylus sp. n. 44, male imago; 45, eXuviae of subimaginal pleuron; 46, left half of eXuviae of subimaginal mesonotum; 47 – 48, female imago; 49, first tarsomere of middle leg of subimago; 50, genitals of male imago; 51, penis of male imago (45 – 46, 50 – 51, holotype).

FIGURES 52 – 53. Anafroptilum orthostylus sp. n., eggs.

FIGURES 54 – 59. Anafroptilum odontostylus sp. n., larva. 54, eXuviae of abdominal sterna (left) and terga (right); 55, enlarged portion of cercus; 56, eXuviae of left half of pronotum and mesonotum; 57, lateral margin of IX abdominal segment; 58, abdominal tergum X; 59, apeX of femur (54 – 55, 57 – 59, holotype).

FIGURES 60 – 64. Anafroptilum odontostylus sp. n., larva. 60, labrum; 61 – 62, left and right mandibles; 63, mola of left mandible; 64, claw (60, 61, 64, holotype). Abbreviations: al, apical lamella of molar process; dmp, distal molar projection.

FIGURES 65 – 68. Anafroptilum odontostylus sp. n., eXuviae of larval abdomen. 65, median part of tergum III; 66, posterior part of tergum IX; 67, median part of sternum VIII; 68, posterior part of sternum IX of male with protogonostyli. Arrows show pairs of submedian pores; abbreviations: sVIII, sIX, sterna VIII and IX; tIII, tIX, terga III and IX.

FIGURES 69 – 77. Anafroptilum odontostylus sp. n., larvae. 69 – 75, tergalii I – VII; 76, labrum and part of clypeus; 77, maXilla, dorsal view (76, holotype). Abbreviations: c 1, c 2, c 3, maXillary canines; ds 1, ds 2, ds 3, dentisetae.

FIGURES 79 – 81. Anafroptilum odontostylus sp. n. 79, genitals of male imago; 80, gonostyli of male subimago; 81, larval paraproct (79 – 80, holotype). Abbreviations: gs 1, gs 2, gs 3, segments of gonostylus; m. IX-X, areas of anterior attachment of median paraproctal muscles (i. e., muscles going from sternum IX to common base of paraprocts); usg, unistyliger.

FIGURES 82 – 85. Anafroptilum odontostylus sp. n. 82, male imago; 83, right half of eXuviae of subimaginal mesonotum; 84, eXuviae of subimaginal pleuron; 85, genitals of male imago (85, holotype).

FIGURES 86 – 87. Anafroptilum spp., median portion of posterior margin of abdominal tergum IX of larva. 86, Anafroptilum kazlauslasi (holotype); 87, Anafroptilum bifurcatum (USA, Nebraska, Cherry Co., R + 61, Snake River, 6. VI. 1995, coll. B. Kondratieff).