Review of Centroptella Braasch & Soldán 1980 (Ephemeroptera, Baetidae) Author Kluge, Nikita J. text Zootaxa 2021 2021-10-19 5054 1 1 144 journal article 3967 10.11646/zootaxa.5054.1.1 c7ac2c61-e8c5-483c-83ae-8af28635f4ac 1175-5326 5577421 75417CFA-BF40-4B6F-A317-DEBFB447893D 2.4. Centroptella ( Crassolus ) ingridae Kluge et al . 2020 ( Figs 7–9 , 264 , 330–336 , 395–413 ) Chopralla sp. : Waltz and McCafferty 1987a: 183 (larva in list of material examined); Centroptella liebenauae : Soldán, Braasch & Muu 1987: 342 (partim: larva, non imago); Bungona ( Chopralla ) liebenauae : Salles, Gattolliat & Sartori 2015: 104 , figs 6D (larva); Appendix S3 (partim: larval characters 0–19 and 31–121); Sroka et al . 2019 : fig. 6B (larva); Shi & Tong 2019: 582 , figs 60–67 (larva); Centroptella ingridae Kluge, Godunko & Svitok 2020: 109 (larva, subimago, ♂ and ♀ imagines, egg). Material examined. THAILAND : holotype and paratypes ; VIETNAM : (part of paratypes of Centroptella liebenauae ) ( Kluge et al . 2020 ). Descriptions. Larva. CUTICULAR COLORATION: Frontal side of head colorless; occipit either also colorless, or with brown ( Kluge et al . 2020 : figs 83–86). Pronotum and mesonotum with contrasting brown, ochre and/or colorless areas, forming characteristic pattern ( Kluge et al . 2020 : figs 83–85). Thoracic pleura and metanotum partly brown, partly colorless; sterna colorless. Each leg with coxa and trochanter colorless; either femora of all legs entirely colorless, or femora of fore and middle legs with diffuse brown macula in distal part on posterior and/or anterior surfaces; tibia and tarsus with more or less expressed diffuse brown coloration, mainly on outer side; claws brownish ( Figs 399–401 ). Abdominal terga with contrasting brown, ochre and/or colorless areas forming characteristic pattern; most terga with large, paired, transverse blanks, which occupy medioposterior sigilla and stretch laterally from them ( Figs 404–405 ). Caudalii colorless at base, diffusely darkened at middle ( Kluge et al . 2020 : figs 85, 129–131). HYPODERMAL COLORATION: Either non-expressed, or represented by reddish stripes on posterior margins of abdominal terga. FIGURES 395–398. Centroptella ( Crassolus ) ingridae , larva. 395, labrum (SEM picture by R. Godunko); 396–397, left and right mandibles; 398, male abdominal terga with reddish and orange hypodermal coloration visible through cuticle. SHAPE: Labrum equally wide at base and middle ( Kluge et al . 2020 : fig. 116). Mandibles ( Figs 396–397 ): incisor of left mandible terminated with 4 denticles decreasing from most distal to most proximal; incisor of right mandible terminated with 3 denticles of subequal width and vestigial 4th denticle; left and right incisors with outer-ventral denticle; prostheca of left mandible with 3 blunt processes and 2–4 pointed processes; prostheca of right mandible directed medially-distally, with short, apical denticles and without long branch; median margin of right mandible proximad of prostheca either without processes, or with small seta-like processes. Maxillary palp nearly as long as lacinia, 2-segmented, with 2nd segment about twice longer than 1st segment. FIGURES 399–403. Centroptella ( Crassolus ) ingridae , larval legs. 399–401, fore, middle and hind legs; 402–403, portions of fore femur. Pronotum with pair of protuberances near posterior margin ( Kluge et al . 2020 : figs 87, 88, 111). Metanotum either with short vestiges of hind protoptera, or without them (in some individuals differently on left and right sides, as in Figs 510–511 ). Forelegs longest, hind legs shortest; on all legs, tarsus (measured on outer side) longer than tibia ( Figs 399–401 ). All femora parallel-sided, outer margin straight or slightly concave, inner margin slightly convex. Foreleg without patella-tibial suture, middle and hind legs with patella-tibial suture greatly shifted to apex of tibia [see Centroptella s. l. (2)]. Claw with two rows of 0–3 denticles in each ( Kluge et al . 2020 : figs 126–127) [see Crassolus (2)]. Denticles on posterior margins of abdominal terga and sterna flat (not conic). Tergum I without denticles; terga II–VI with short semicircular and triangular denticles ( Fig. 404 ; Kluge et al . 2020 : figs 95–99); terga VII–IX with longer triangular denticles ( Kluge et al . 2020 : figs 100–102); on tergum IX middle part of hind margin behind pair of submedian setae without denticles and projected posteriorly ( Kluge et al . 2020 : figs 102). Posterior projection of tergum X without denticles on median part, laterally with paired groups of several denticles, decreasing in length in lateral direction ( Kluge et al . 2020 : fig. 93). Sterna I–IV without denticles; sterna V–VIII with regular, small, pointed, triangular denticles ( Kluge et al . 2020 : figs 103–107). Posterior margin of sternum IX in female convex, with row of triangular denticles diminished medially ( Kluge et al . 2020 : fig. 109), in male without denticles between protogonostyli ( Kluge et al . 2020 : figs 108, 148). Paraprocts with small antero- median apodeme, with few large pointed denticles on posterior margin, with scales as on sterna and terga ( Kluge et al . 2020 : figs 93, 120–121). FIGURES 404–406. Centroptella ( Crassolus ) ingridae , larval cuticle of abdomen. 404, tergum III of holotype (MA, medioanterior sigillum; MP, medioposterior sigillum); 405, terga and sterna; 406, tergum VII (letter g corresponds to Fig. 14). FIGURES 407–413. Centroptella ( Crassolus ) ingridae . 407–409, fore, middle and hind legs of male imago; 410, exuviae of subimaginal mesopleuron; 411, exuviae of subimaginal mesonotum; 412–413, egg (407–410, holotype). Tergalius I narrow, elongate-ellipsoid; other tergalii wider, gradually changing in shape from tergalius II to tergalius VII ( Figs 330–336 ). Each tergalius II–VII, besides costal and anal ribs, with straight and narrow middle rib, located on dorsal surface on background of main trachea ( Kluge et al . 2020 : fig. 125) (see Centroptella s. l. ). Enlarged denticles on outer side of cercus located on every 4th segment and arranged by 1 (occasionally 2) on each side of secondary swimming setal row [see Centroptella s. l. (3)]; largest denticles reach midlength of next segment ( Kluge et al . 2020 : figs 129–132). SCALES: Head, antennae, pronotum, partly mesonotum, femora and tibiae of legs densely covered with fine, colorless, hair-like scales with very small sockets (about 2 mkm) and with somewhat wider, also colorless, band-like scales (with sockets about 4 mkm) ( Fig. 403 ; Kluge et al . 2020 : figs 110–111). Scales on abdominal terga and sterna numerous, elongate, varying in size and shape, bordered by brown ( Figs 404–406 ; Kluge et al . 2020 : figs 94–102). STOUT SETAE: Outer side of femur with regular or irregular row (or two rows) of 9–16 long, clavate, colorless setae and 2 subapical setae of same form ( Figs 399–402 ; Kluge et al . 2020 : figs 90–92). Inner-anterior side of each femur with few minute (5–10 mkm length), stout, blunt setae; no longer setae on inner-anterior side of fore femur ( Fig. 402 ). Tibia and tarsus with stout setae on inner side. Outer-apical seta of tibia blunt and elongate ( Figs 7–9 ). LONG, FINE SETAE: Bifurcate setae of metasternum (i) (see Centroptella s. l. ) short, forming pair of sparse rows. Posterior arm of U-shaped row of long setae on fore- and middle leg situated across tibia, on hind leg longitudinal ( Figs 7–9 ) [see Crassolus (1)]. Dorsal side of each tarsus with long, fine setae situated irregularly and partly forming two longitudinal rows (as in Figs 562–563 ; see Centroptella s. l. ). Tergum VII with pair of fine, V-shaped setae sublaterally (g) ( Fig. 406 ). Each sternum IV–VI with pair of regular, transverse rows of long, fine, bifurcate setae with spaced sockets (j) ( Kluge et al . 2020 : figs 117–119); other sterna either without such setae, or with few, smaller setae irregularly situated (see Centroptella s. l. ). MALE GENITALIA IN LARVA: In last larval instar, developing subimaginal gonostyli folded under larval cuticle in peculiar « Crassolus - type » pose, with 3rd segments bent medially-proximally ( Kluge et al . 2020 : fig. 148) [see Crassolus (5)]. RESPIRATORY MOVEMENTS: Tergalii able to make rhythmic respiratory movements. Subimago. CUTICULAR COLORATION: Head and antennae colorless, with microtrichia dark brown. Pronotum brown. Mesonotum brown with certain sutures darker and medioparapsidal suture colorless ( Fig. 411 ). Thoracic sterna and pleura with brown and colorless areas ( Fig. 410 ). Cuticle of legs colorless with microtrichia brown. Wings light, without brown circles at bases of microtrichia. Abdominal terga, sterna and cerci light brownish. HYPODERMAL COLORATION: As in imago. TEXTURE: On all legs of both sexes all tarsal segments entirely covered with pointed microlepides (as in Fig. 391 ). Imago, male ( Kluge et al . 2020 : figs 135, 139–143). Head brown. Turbinate eyes relatively low and wide, with yellow stem and orange-red facetted surface. Thorax dark brown, with ochre pleural membranes Wing with membrane colorless, veins pale ochre or colorless, extreme base of costal and subcostal veins proximad of costal brace brown. Femora of all legs ochre, apically diffusely tinged with reddish; fore tibia light ochre, apically darkened with light brownish; middle and hind tibiae ochre, with diffuse reddish longitudinal stripe; tarsi of all legs pale ochre; claws brown ( Figs 407–409 ). Tarsus of middle and hind legs with 1 apical spine on initial 3rd tarsomere (next after 1st+2nd tarsomere) (as in Kluge et al . 2020 : fig. 137). Abdominal tergum I colorless; terga II–VI colorless with narrow, contrasting, reddish stripe bordering posterior margin; terga VII–X red with ochre, with darker stripe bordering posterior margin; abdominal sterna colorless; lateral tracheal trunks and some other abdominal tracheae bordered with blackish ( Kluge et al . 2020 : fig. 139). Cerci ochre, 2–3 most proximal segments with joinings reddish-brown. Genitalia ( Kluge et al . 2020 : figs 140–143, 146). Sterno-styligeral muscle entirely absent [see Crassolus (7)]. Gonostylus with 1st segment narrowed apically; 2nd segment thickened toward apex; 3rd segment elongate, narrow and thickened toward apex. Penial bridge medially sharply concave, with narrow, trapezoid, colorless process. Gonovectes apically with halberd-like widenings [see Crassolus (6)]. Imago, female ( Kluge et al . 2020 : figs 133–134, 138). Head and thorax ochre with reddish markings. Leg coloration as in male. Patella-tibial suture present on middle and hind legs, absent on forelegs [as in male; see Centroptella s. l. (2)]. Tarsus of each leg with 1 apical spine on initial 3rd tarsomere (on foreleg—on tarsomere next after 2nd tarsomere, on middle and hind leg—on tarsomere next after 1st+2nd tarsomere) ( Kluge et al . 2020 : fig. 137). Abdominal terga intensely colored with ochre and reddish, partly repeating cuticular color pattern of larva; abdominal sterna nearly colorless, sterna I–VI with pair of reddish maculae near antero-lateral corners. Egg ( Figs 412–413 ). Oval; chorion smooth, without relief. Sperm guide wide, shallow and not outlined distally. Dimension. Fore wing length of male 4.7 mm ; of female 5.0 mm. Distribution. Indochina and southern China . Material examined comes from Thailand and Vietnam . In China this species is reported from Yunnan , Guangxi and Guangdong under the species name C. liebenauae ( Shi & Tong 2019 ) . FIGURES 414–418. Centroptella ( Crassolus ) pontica (photos by R. Godunko). 414–415, fore and hind legs of female larva, with subimaginal legs visible through larval cuticle; 416, fragment of larval cercus; 417, cuticle of larval abdominal terga; 418, male larva withy dark brown hypodermal coloration visible through cuticle. Comment. The description given above contains some corrections and clarifications to the original description. In the original description ( Kluge et al . 2020 ) we wrongly reported that «Inner-dorsal side of fore femur with few stout setae, length of these setae being half that of setae on dorsal side». Actually, in C . ( Crassolus ) ingridae the stout setae on outer side of femora are long and more numerous than in other species, while the stout setae on inneranterior side of fore femur are very small, many times shorter than the setae on outer side ( Fig. 402 ).