Anafroptilum orthostylus, Kluge, Nikita J. & Novikova, Eugenia A., 2017

Kluge, Nikita J. & Novikova, Eugenia A., 2017, Occurrence of Anafroptilum Kluge 2012 (Ephemeroptera: Baetidae) in Oriental Region, Zootaxa 4282 (3), pp. 453-472 : 461-463

Anafroptilum orthostylus sp. n.

( Figs 1–53 )

Etymology. Referring to straight shape of male imaginal gonostyli ( Figs 41 , 50 ).

Material examined. Holotype: L-S-I ♂ {specimen [X] (13) 2015}, THAILAND, Kanchanaburi Province, Erawan Falls , 6.II.2015, coll. N. Kluge & L. Sheyko . Paratypes: the same locality, 2–4.II.2015, coll. N. Kluge & L. Sheyko: 2 S-I ♂ , 24 I ♂, 1 L/S♂, 1 L♂, 5 S-I♀, 1 I ♀, 2 L/S♀.

Descriptions. Larva. Cuticular coloration. Head with colorless and very light brownish areas. Pronotum and mesonotum light brownish with darker brown markings; protoptera light with darker stripes corresponding to longitudinal veins ( Fig. 4 ). Metanotum, thoracic pleura and sterna brown, membranes colorless ( Figs 1–3 ). Legs at most part colorless, with brown band at distal part of femur ( Fig. 1 ), sometimes also with brown marking at base of femur and at apex of tibia. Abdomen with variable brown and colorless areas; in all 5 examined individuals, tergum II with contrasting dark brown V-shaped middle spot ( Figs 2, 5–8 ); terga III–V either nearly entirely colorless ( Fig. 6 ), or with more or less extensive brown maculation; tergum VI darkest, sometimes much darker than others ( Figs 2, 6 ). Abdominal sterna with large brown median markings, sometimes darker than terga ( Fig. 3 ). Among 5 examined larval individuals, all 3 male larvae have abdominal tergum and sternum VI contrastingly much darker than others ( Figs 1–3, 5, 6 ) and both female larvae have abdominal coloration less contrasting ( Figs 7, 8 ); possibly, sex-specific character. Cerci and paracercus at most part colorless or light ocher, each with two contrasting narrow brown bands: one at middle and another at distal part; darkening on posterior margin of each 4th segment poorly expressed ( Figs 1, 3, 4 ). On light portions of cerci and paracercus swimming setae also light; on brown bands each swimming seta brown proximally, colorless distally ( Figs 9–10 ).

Hypodermal coloration. Not expressed.

Structure. Frons between antennae with flat elevation; frontal suture relatively long and obtuse-angled ( Fig. 37 ). Labrum truncate, nearly rectangular; dorsal surface with irregularly situated setae [without constant pair of submedian setae and/or pair of latero-distal setal rows –see Anafroptilum (9)] ( Figs 12 , 35 ). Both mandibles with incisor and kinetodontium deeply separated [see Anafroptilum (10)]; planes of incisor, kinetodontium and prostheca perpendicular to plane of mandible ( Figs 13–14 , 38–39 ). On left mandible incisor with 4 thick denticles and slender ventral denticle; kinetodontium with 3 thick denticles and serration on dorsal margin; prostheca bifurcate ( Fig. 38 ). On right mandible incisor with 3 thick apical denticles and slender ventral denticle; kinetodontium with 2 thick apical denticles and thin denticles on both margins; prostheca asymmetrically pointed ( Fig. 39 ). Molar processes of left mandible longer than distal molar projection; each process terminated by elongate apical lamella ( Fig. 15 : al). Maxilla with 3 canines, 3 dentisetae, 2–4 setae proximad of dentisetae and 9–11 setae of inner ventral row; all canines, dentisetae and setae slender, pointed and bent at the same direction ( Fig. 17 ; as in Fig. 77 ) [see Anafroptilum (12)]. Maxillary palp 2-segmented ( Fig. 17 ). Labium with glossae and paraglossae narrowed near bases, widened at midlength; setae of median row of glossa relatively short, shifted to dorsal side of glossa; setae of dorso-lateral row of glossa relatively short; setae of dorso-median row of paraglossa located far from median margin ( Fig. 36 ). Labial palp with 2nd segment bearing weak muscle, 3rd segment widened apically and truncate ( Fig. 16 ; as in Fig. 78 ) [see Anafroptilum (2)].

Hind protoptera completely absent. Legs as in A. kazlauskasi ( Kluge 2012: Figs 38–40 ): femora nearly parallel-sided, fore femur widest at middle, middle and hind femora widest at apex; apex of each femur finely serrate (as in Fig. 59 ); each femur without stout setae on outer margin and apex; only inner margin with few small stout setae [see Anafroptilum (14)]; fore tibia without patella-tibial suture, middle and hind tibia with patella-tibial suture [see Anafroptilum (1)]; each tibia with short ark of fine setae at outer side near base; outer side of tibia and tarsus without stout setae, inner side of tibia and tarsus with sparse spine-like setae. Claw with two equal regular rows of numerous slender denticles, reaching 1/2 of claw length ( Fig. 18 ) [see Anafroptilum (5)].

Abdominal terga and sterna with small denticles and narrow scales; scales sparse on anterior segments and dense on II–X terga and III–IX sterna ( Fig. 19 ); sterna with irregularly situated simple long setae (as in Fig. 67 ). Posterior margin of abdominal tergum I without denticles; posterior margins of terga II–VI with small blunt denticles ( Fig. 19–21 ); posterior margins of terga VII–X with longer and pointed denticles ( Figs 22–23 ); tergum IX without denticles behind pair of submedian pores ( Fig. 23 ); tergum X as in A. odontostylus sp. n. ( Fig 58 ). Posterior margin of abdominal sterna I–III without denticles; posterior margin of sterna IV–VIII with very small blunt and cleft denticles ( Fig. 24–25 ); posterior margin of sternum IX of female larva with similar blunt and cleft denticles ( Fig. 26 ); posterior margin of sternum IX of mature male larva with very short and shallow protogonostyli, with few very small denticles ( Fig. 27 , 43 ). Paraprocts with pointed denticles on apex; most part of median side smooth ( Figs 9 , 40 ). Lateral denticles absent [see Anafroptilum (3)]. Each tergalius I–II with costal rib, without anal rib; each tergalius III–VII with long costal and anal marginal ribs, without denticles, distal margin without rib; tergalius I very narrow, bent backward; tergalius II slightly wider; tergalii III–VI nearly symmetric, widest at distal part; tergalius VII longest, asymmetrically bent backward; each tergalius with contrasting dark brown middle macula formed by pigment granules on main trachea ( Figs 28–34 ). Cerci with small denticles on all segments; one simple or composed larger spine can be present on lateral side of cercus near tip, distad of distal brown band ( Figs 10, 11 ). Among 5 examined individuals, one has such spine on left and right cercus ( Fig. 11 ), one (holotype) has spine on right cercus and vestigial spine on left cercus ( Figs 9–10 ), one has spine on left cercus and no spine on right cercus, one has no spines on both cerci ( Figs 1–3 ), and one has no spine on right cercus and left cercus missing. Outer side of cercus with additional row of sparse fine colorless setae ( Fig. 11 ).

Subimago. Cuticular coloration. Head colorless. Pronotum and prosternum light brown. Mesonotum nearly colorless with brown microtrichia, certain sutures light brown ( Fig. 46 ). Thoracic pleura and sterna at most part nearly colorless with brown microtrichia, certain sclerites light brow ( Fig. 45 ). Legs nearly colorless with brown microtrichia. Abdominal terga and sterna very light brownish with brown microtrichia; terga with brownish sublateral markings. Cerci colorless with brown spines.

Texture. On fore legs of male and female all tarsomeres covered by pointed microlepides. On middle and hind legs of both sexes proximal half of 1st tarsomere (corresponding to primary 1st tarsomere) covered by microtrichiae (as tibia), distal half of 1st tarsomere and other three tarsomeres (corresponding to 2nd–5th primary tarsomeres) covered by pointed microlepides ( Fig. 49 ) [see Anafroptilum (7)].

Imago, male ( Fig. 44 ). Turbinate eyes with stem dull reddish, grayish distally; facetted surface dull reddish. Thorax brown with membranous areas white because of fat located under cuticle. Legs pale ocher, femur with white spot (formed by internal fat) at middle and near apex. In holotype, proportion of femur / tibia / tarsal segments of fore leg 70: 90: 3: 40: 27: 15: 13; middle leg 60: 52: 19: 6: 3: 12; hind leg 60: 47: 19: 6: 3: 12. Tarsus of middle and hind leg with one apical spine on 2nd tarsomere (primary 3rd tarsomere). Fore wing with membrane and veins colorless; pterostigma with 2–4 simple oblique veins. Hind wings absent. Abdominal segments I–VI colorless and translucent, with pair of dark brown stripes on lateral tracheal trunks; VII–X terga brown, sterna lighter. Cerci unicolor light ocher.

Unistyligers and gonostyli colorless ( Fig. 50 ). Unistyligers basally separated, with styligeral muscle attached between them ( Fig. 41 ). Finger-like projection between unistyligers ( Figs 41 , 50 ). 1st segment of gonostylus without projection; 2nd segment nearly straight; 3rd segment relatively small ( Figs 41 , 50 ) [see Anafroptilum (15)]. Penis light brownish; external part of penis widely rounded; apical margin of penis with unusual spines bent laterally ( Figs 41 , 51 ).

Imago, female ( Fig. 47–48 ). Head dorsally ocher with variable light brown markings; eyes widely separated. Thorax dorsally light brown with ocher, ventrally light ocher. Tarsus of fore leg with one apical spine on 3rd tarsomere; middle and hind legs as in male. Abdomen ocher with variable brown markings on terga, with lateral brown stripes on sterna.

Eggs ( Figs 52–53 ). About 0.12 mm length. Elongate-oval, with regular net-like relief.

Dimension. Fore wing length of male and female 3.5 mm.

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 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 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 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.