Centroptella (Chopralla) ceylonensis Müller-Liebenau 1983

Kluge, Nikita J., 2021, Review of Centroptella Braasch & Soldán 1980 (Ephemeroptera, Baetidae), Zootaxa 5054 (1), pp. 1-144 : 96-105

3.1. Centroptella (Chopralla) ceylonensis Müller-Liebenau 1983

( Figs 429–488 )

Centroptella ceylonensis Müller-Liebenau 1983: 486 (larva);

Centroptella similis Müller-Liebenau 1983: 487 (larva), syn. n.

Chopralla ceylonensis Waltz & McCafferty 1987a: 183 ;

Chopralla similis: Waltz & McCafferty 1987a: 183 ;

Bungona (Chopralla) ceylonensis: Salles, Gattolliat & Sartori 2016: 104 , figs 4E, 5G, 6G, 6M;

Bungona (Chopralla) similis: Salles, Gattolliat & Sartori 2016: 104 ;

Bungona (Chopralla) pusilla and Bungona (Centroptella) pusilla: Selvakumar, Kubendran, Chandra Kailash & Sidhu Avtar Kaur 2017: 274 (larva).

Material examined. SRI LANKA: border of Uva and Central Provinces, tributary of river Uma near Randenigala dam, 13–14.I.2011, coll. N. Kluge & L. Sheyko: 5 larvae ; Uva Province, Badulla District, Haputale , 15–23.I.2011, coll. N. Kluge & L. Sheyko: 1 L-S-I ♂ ; Uva Province, Badulla District, Lemastota Oya , 20–21.I.2011, coll. N. Kluge & L. Sheyko: 2 larvae ; Sabaragamuwa Province, river Seetha Sangula in Dalhausie near Sri Pada ( Adam’s Peak ), 24–26.I.2011, coll. N. Kluge & L. Sheyko: 2 S-I ♂, 22 larvae ; the same place and collectors, 1–10.II.2020: 5 L-S-I ♂, 11 L-S-I ♀, 1 S-I ♀, 31 larvae; river Battulu Oya, Fishing Hut (S of Sri Pada = Adam’s Peak ), 8–9.II.2020: L/S ♀, 1 larva ; Central Province, Nuwara Eliya District, river Mahaveli Ganga in Ginigathhena (17 km N Hatton), 31.I–3.II.2011, coll. N. Kluge & L. Sheyko: 2 L-S-I ♂ , 9 S-I ♂, 6 I ♂, 5 S-I ♀, 3 I ♀, 1 S ♀, 3 larvae; Belihuloya , 15– 26.I.2020, coll. N. Kluge & L. Sheylo: 1 L-S-I ♀ , 1 I ♀, 6 larvae; Wellawaya , 22.I.2020, coll. N. Kluge & L. Sheyko: 2 larvae . INDIA: State Karnataka, Udupi District, river Seethanadhi-hole near Someswar , 11.I–1.II.2013, coll. N. Kluge & L. Sheyko: 2 L-S-I ♂ , 3 L-S-I ♀, 1 L-S ♀, 9 larvae. State Kerala, Kottayam District, Erumeli , 22.I.2016, coll. N. Kluge & L. Sheyko: 3 L-S-I ♀ , 3 L; Ernakulam District, Malayatoor , 14–15.II.2016, coll. N. Kluge & L. Sheyko: 10 L-S-I ♂ , 1 L-S ♂, 1 L-S-I ♀, 6 larvae.

Descriptions.

Larva. CUTICULAR COLORATION: Head with anterior side mostly colorless, frons can be bordered with brown (i.e. with brown arc connecting paired ocelli), median brown spot can be located just posteriad median ocellus; genae brown or colorless; dorsal side of head brown ( Fig. 430 ). Pronotum and mesonotum with contrasting brown, ochre and/or colorless areas, forming characteristic pattern ( Fig. 431 ). Thoracic pleura and metanotum partly brown, partly colorless; sterna colorless. Legs with coxae partly colorless, partly brown; trochanteres colorless. Fore femur with long brown macula on posterior side and brown outer side, other sides mostly colorless; middle femur with smaller brown macula on posterior side and brown outer side; hind femur mostly colorless, with brown macula on posterior side near inner margin; tibia of each leg diffusively darkened with brown along rows of long, fine setae; tarsus of each leg brown proximally and along rows of long, fine setae; claws brown ( Figs. 434–436 ; as in Figs 554–559 ). Abdominal terga with contrasting brown, ochre and/or colorless areas forming characteristic pattern; each tergum II–VI with unpaired, median blank; among them, each tergum II–III and V–VI with pair of large, transverse blanks located posteriad-laterad of medioposterior sigilla; among them, terga III and V with more anterior pair of transverse blanks located laterad of medioanterior sigilla; on terga II and IV blanks occupy most part of tergum; terga VII–VIII mostly light (from colorless to light brown), with posterior and/or anterior margins bordered by darker brown; terga IX–X mostly brown ( Fig. 429 ; Müller-Liebenau 1983: figs 4, 6); medio-anterior and medioposterior sigilla lighter than background (as in Fig 540 ). In some individuals coloration of abdominal terga mostly dark, and blanks not expressed. Caudalii light at base (from colorless to light brown), diffusely darkened distally ( Figs 429, 437–438 ).

HYPODERMAL COLORATION: Abdomen of larvae of both sexes with composite and extensive reddishbrown hypodermal color pattern as in winged stages ( Figs 456–457, 460 ).

SHAPE: Labrum either equally wide at base and middle, or slightly wider at base (as in Fig. 507 ; Müller-Liebenau 1983: fig.1a). Mandibles ( Figs 439–448 ): 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, without 4th denticle; left and right incisors with outer-ventral denticle; prostheca of left mandible with 3 blunt processes and 2–3 pointed processes; prostheca of right mandible directed medially or medially-proximally, bifurcate, with longest branch directed medially-proximally or proximally; median margin of right mandible proximad of prostheca with short seta-like processes. Maxillary palp nearly as long as lacinia, 2-segmented, with 2nd much longer than 1st segment ( Fig. 432 ).

Pronotum without protuberances (in contrast to C. ingridae ). 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 fore leg tarsus (measured on outer side) as long as tibia; on middle and hind legs tarsus slightly shorter than tibia ( Figs 434–436 ). 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)] ( Müller-Liebenau 1983: figs 1i–l). Claw with two rows of 1–6 denticles in each [see Chopralla (2)] ( Müller-Liebenau 1983: figs 1m –n).

Denticles on posterior margins of abdominal terga and sterna flat (not conic). Terga I–VIII without denticles (in single female from Malayatoor terga VII–VIII with irregular small denticles); tergum IX with long triangular denticles interrupted medially, behind pair of submedian setae ( Fig. 449 ). Posterior projection of tergum X without denticles on median part, laterally with pair of long denticles (as in Fig. 501 ), with or without 1 pair (rarely 2 pairs) of smaller denticles by sides of them ( Fig. 433 ). Sterna I–IV without denticles; sterna V–VIII with regular, small, pointed, triangular denticles. Posterior margin of sternum IX in female convex, with row of triangular denticles interrupted medially ( Fig. 450 ), in male without denticles between protogonostyli ( Fig. 469 ). Paraprocts with thin and colorless antero-median apodeme, with large pointed denticles on posterior margin (as in Fig. 550 ).

Tergalius I narrow, elongate-ellipsoid; other tergalii wider, gradually changing in shape from tergalius II to tergalius VII ( Figs 475–488 ). Each tergalius II–VII, besides costal and anal ribs, with straight and narrow middle rib, located on dorsal surface on background of main trachea (see Centroptella s. l.).

Enlarged denticles on outer side of cercus relatively large (reaching or exceeding midlength of next segment) located on every 2nd or every 4th segment and arranged by 1–3 on each side of secondary swimming setal row [see Centroptella s. l. (3)] ( Figs 437–438 ).

SCALES: Certain areas of pronotum and mesonotum with small, colorless scales. Femora, tibiae and tarsi with colorless, short, oval scales. Scales on abdominal terga numerous, elongate, oval, with longitudinal striation ( Fig. 449 ; Müller-Liebenau 1983: figs 5, 7). Scales on abdominal sterna, thoracic pleura and metanotum shorter and partly colorless ( Fig. 450 ).

STOUT SETAE: Outer side of femur with regular row of 4–15 long, clavate setae and 2 subapical setae of same form ( Figs 434–436 ). Inner-anterior side of each femur with few very short (5–8 mkm length), stout, blunt setae. On fore leg inner-anterior side of trochanter and/or proximal part of femur with or without one or several longer (15–20 mkm length), stout, pointed, setae with small denticles by sides (as in Figs 41 , 362–363 ). Tibia and tarsus with small stout setae on inner side. Outer-apical seta of tibia small, blunt and elongate (as in Fig. 364 ).

LONG, FINE SETAE: Bifurcate setae of metasternum (i) (see Centroptella s. l.) form pair of dense, regular rows partly with contiguous sockets (as in Fig. 517 ). Posterior arm of U-shaped row of long setae on fore- and middle leg situated across tibia, on hind leg longitudinal ( Müller-Liebenau 1983: figs 1i–l) [see Chopralla (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) (as in Fig. 406 ). Each sternum IV–V with pair of regular, transverse rows of long, fine, bifurcate setae with spaced sockets (j); other sterna either without such setae, or with few setae irregularly situated.

MALE GENITALIA IN LARVA: In last larval instar, developing subimaginal gonostyli folded under larval cuticle in « Nigrobaetis - type » pose, with 2nd and 3rd segments directed caudally and inserted into previous ones ( Fig. 469 ) [see Chopralla (5)].

RESPIRATORY MOVEMENTS: Tergalii able to make rhythmic respiratory movements.

Subimago. CUTICULAR COLORATION: Head nearly colorless, antennae light brown. Pronotum light brown. Mesonotum light brown with certain sutures darker and medioparapsidal suture colorless ( Fig. 453 ). Thoracic sterna and pleura mostly colorless, with certain sclerites brown ( Fig. 452 ). Legs mostly colorless. Wings light, without brown circles at bases of microtrichia. Abdominal terga and cerci light brownish, sterna nearly colorless.

HYPODERMAL COLORATION: As in imago (see below).

TEXTURE: On all legs of both sexes all tarsal segments entirely covered with pointed microlepides (as in Fig. 391 ).

Imago, male ( Fig. 451 ). Head ochre with reddish-brown. Turbinate eyes relatively low and wide, entirely orange. Thorax contrastingly darker (ochre with reddish-brown) in dorsal half and lighter (pale ochre) in ventral half. Wing with membrane colorless, veins pale ochre or colorless, extreme base of costal and subcostal veins proximad of costal brace brownish. Femora of all legs ochre, apically more or less intensively tinged with reddish; fore tibia light ochre, apically tinged with reddish; middle and hind tibiae ochre, with more or less expressed longitudinal reddish stripe; tarsi light ochre ( Figs 454–455 ). Tarsus of middle and hind legs with 1 apical spine on initial 3rd tarsomere (next after 1st+2nd tarsomere) (as in Fig. 392 ). Abdominal terga dark ochre with extensive reddish-brown hypodermal markings ( Figs 456–463 ); abdominal sterna ochre, some sterna with pair of reddish-brown longitudinal stripes sublaterally ( Figs 456–458 ; lateral tracheal trunks and some other abdominal tracheae bordered with blackish. Cerci ochre, in proximal part with joinings reddish-brown.

Genitalia ( Figs 465–468 ). Sterno-styligeral muscle slender and paired [see Chopralla (7)]. Gonostylus with 1st segment narrowed apically; 2nd segment thickened toward apex; 3rd segment either short, or elongate, thickened toward apex. Penial bridge medially with large, sclerotized, hemispheric or conic projection. Gonovectes shallowly bent S-like, i.e. with apices bent cranially.

Imago, female ( Figs 470–472 ). Coloration of head, thorax, abdomen, wings and cerci as in male. Fore tibia ochre, tinged with reddish on inner side; other 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) (as in Figs 391–392 ).

Egg ( Figs 473–474 ). Oval; chorion with isoedric net-like relief, with very sparsely and irregularly arranged minute pores. Sperm guide small and deep.

Dimension. Fore wing length of male and female 3.2–5 mm.

Synonymy of C. ceylonensis and C. similis . Müller-Liebenau (1983) described Centroptella ceylonensis and C. similis bases on larvae only and stated that «The main difference between both species is the lack of hind wing pads in C. similis sp. n. (in both sexes)». In reality, presence and size of larval vestiges of hind protoptera varies individually in this species (while hind wings are always completely absent in winged stages); among examined larvae of C. ceylonensis from one and the same population (Delhausie near Sri Pada), some individuals have wellexpressed vestiges of hind protoptera, some have very small convexities instead of them, some have not vestiges of hind protoptera at all, and some have vestige of hind protopteron on one side and no such vestige on another side (as in Figs 510–511 ).

Besides this character, Müller-Liebenau (1983) noted: «Also the size ratio of turbinate eyes and the lateral eyes appears somewhat different in the male nymphs of both species». Actually, the drawings of male larval heads ( Müller-Liebenau 1983: figs 1p and 2a) do not allow to distinguish these species.

Müller-Liebenau (1983) also noted that scales on abdominal terga are «in general a little more elongate in C. ceylonensis sp. n. ». Actually, the scales significantly vary in size and proportions on terga of one and the same individual, that is visible from the photos in the original description ( Müller-Liebenau 1983: figs 5, 7).

According to the original description of C. similis , its cuticular coloration of larval abdomen somewhat differs from that of C. ceylonensis . Actually, the coloration of abdominal cuticle varies individually in greater degree than it is shown on the pictures in the original descriptions of C. ceylonensis and C. similis . Thus, the name C. similis should be regarded as a junior synonym of C. ceylonensis .

Distribution. Southern India (Western Ghats) and Sri Lanka.

Variability. Hypodermal coloration of abdomen significantly varies individually within each population ( Figs 456–463 , 470–472 ). The examined specimens from Sri Lanka are larger (fore wing length 4.5–5 mm) then the examined specimens from India, whose fore wing length is 3.5–4 mm. However, examination of many imagines of both sexes individually associated with their larval and subimaginal exuviae allowed to conclude that populations from Sri Lanka and India belong to one and the same species.

Species determination. In Sri Lanka Centroptella (Chopralla) ceylonensis is the single species of Chopralla and cannot be confused with other species. In southern India C. (Ch.) ceylonensis can be confused with the closely related species C. (Ch.) ghatensis sp. n., whose larvae differ only by presence of denticles on abdominal terga V–VIII and winged stages are indistinguishable from C. (Ch.) ceylonensis .

Selvakumar et al. (2017) determined larvae of Chopralla from southern India as C. pusilla . Resolution of the total photo ( Selvakumar et al. 2017: fig. 6) allows to see a pair of large denticles on lateral angles of the posterior projection of tenth abdominal tergum, that differs C. ceylonensis ( Fig. 433 ) from C. pusilla ( Fig. 630 ); other characters of the larvae reported by Selvakumar et al. (2017) (i.e. coloration, mandibular structure, arrangement of denticles on abdominal terga) also agree with the characteristics of C. ceylonensis . The photo indicated as «Foreleg» ( Selvakumar et al. 2017: fig. 10) actually belongs to the hind leg.

Figures

FIGURES 429–438. Centroptella (Chopralla) ceylonensis, larva. 429, abdomen; 430, head; 431, pronotum and mesonotum; 432, maxilla; 433, abdominal tergum X; 434–436, fore, middle and hind legs; 437–438, cerci of different specimens.

FIGURES 439–448. Centroptella (Chopralla) ceylonensis, mandibles. 439–440, left mandible, dorsal and median view; 441– 442, left and right mandibles of penultimolarva before molt to ultimolarva (with mandibles of next instar inside); 443–444, the same, another specimen; 445–448, right prostheca of different species. Abbreviations: in1–in4, denticles of incisor; kd1–kd3, denticles of kinetodontium; o-v.d, outer-ventral denticle of incisor; prs, prostheca.

FIGURES 449–450. Centroptella (Chopralla) ceylonensis, exuviae of larval abdomen. 449, tergum IX; 450, sternum IX of female.

FIGURES 451–463. Centroptella (Chopralla) ceylonensis. 451, male imago; 452, subimaginal exuviae of mesopleuron; 453, subimaginal exuviae of mesonotum; 454–455, fore and middle legs of male imago; 456–457, abdomina of male imagines extracted from larvae; 458–463, abdomina of male imagines (451–459, specimens from Sri Lanka; 460–463, specimens from India).

FIGURES 464–469. Centroptella (Chopralla) ceylonensis. 464, subimaginal exuviae of gonostylus; 465–468, genitalia of male imagines; 469, subimaginal gonostyli crumpled under larval cuticle. Abbreviations as in Figs 303–307.

FIGURES 470–474. Centroptella (Chopralla) ceylonensis. 470–472, female imagines; 473–474, egg.

FIGURES 475–495. Tergalii I–VII. 475–481 and 482–488, Centroptella (Chopralla) ceylonensis; 489–495, Centroptella (Chopralla) ghatensis sp. n.

FIGURES 551–559. Centroptella (Chopralla) rufostriata sp. n., larval legs. 551–553, translucent exuviae of fore, middle and hind legs with cuticular coloration visible on both sides; 554–556, outer sides of fore, middle and hind legs; 557–559, their inner sides.

FIGURES 534–540. Centroptella (Chopralla) rufostriata sp. n. 534–536, larval exuviae (534, pronotum and mesonotum; 535, abdomen; 536, head); 537–538, female larva of last instar; 539, younger larva with lighter cuticular coloration (grayish) and better visible hypodermal coloration (reddish brown); 540, exuviae of abdominal tergum III (MA, medioanterior sigillum; MP, medioposterior sigillum).

FIGURES 505–511. Centroptella (Chopralla) ghatensis sp. n., larva. 505–506, left and right mandibles of penultimolarva before molt to ultimolarva (with mandibles of next instar inside); 507, labrum; 508, maxilla; 509, labium; 510–511, left and right halves of exuviae of larval metanotum (holotype). Abbreviation: ppt, vestige of hind protopteron; letter g corresponds to bases of bifurcate setae in Fig. 14.

FIGURES 496–504. Centroptella (Chopralla) ghatensis sp. n., larva. 496, cercus (holotype); 497, subimaginal abdomen extracted from larva, to show hypodermal coloration; 498–504, larval exuviae: 498, head; 499, pronotum and mesonotum; 500, abdomen; 501, abdominal segment X; 502–504, fore, middle and hind legs.

FIGURES 541–550. Centroptella (Chopralla) rufostriata sp. n., larva. 541, cercus; 542–543, left and right mandibles; 544, labrum; 545–546, labium; 547–548, claw; 549, maxilla; 550, abdominal segment X without caudalii.

FIGURES 38–42. Centroptella (s. str.) longisetosa cinerea subsp. n., larva. 38, claw; 39, caudalii; 40, cercus (holotype); 41, fore femur; 42, abdominal terga IX–X.

FIGURES 352–363. Centroptella (Crassolus) ludmilae sp. n., exuviae of larval legs. 352, fore femur; 353, seta on outer side of femur; 354–355, claws; 356–358, fore, middle and hind legs; 359–361, fore, middle and hind tibiae (focus on posterior side); 362, stout setae on proximal part of inner-anterior side of fore femur; 363, the same on hind femur.

FIGURES 364–368. Centroptella (Crassolus) ludmilae sp. n., larval exuviae. 364, apex of fore tibia (arrow shows outer-apical seta); 365, abdominal tergum V; 366, abdominal tergum III of holotype (MA, medioanterior sigilla; MP, medioposterior sigilla); 367, abdominal tergum X; 368, female abdominal sternum IX and paraprocts.

FIGURES 512–517. Centroptella (Chopralla) ghatensis sp. n., exuviae of larval thorax. 512–513, scales and bifurcate setae on anterior part of mesonotum (corresponding to e on Fig. 14); 514–517, bifurcate setae on thoracic sternum (corresponding to h and i on Fig. 15).

FIGURES 560–565. Centroptella (Chopralla) rufostriata sp. n., larva. 560–561, fore and middle tibiae, anterior view (setae and sutures on opposite side shown by interrupted lines); 562–563, hind tibia and tarsus, anterior and outer view (bases of long, fine setae shown as rings). 564, abdominal tergum IX; 565, abdominal sternum VII.

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 387–392. Centroptella (Crassolus) ludmilae sp. n. 387–388, female imago; 389, exuviae of subimaginal pleuron; 390, exuviae of subimaginal mesonotum; 391, exuviae of female subimaginal fore and hind legs. Abbreviations: T1–T5, tarsomeres.

FIGURES 626–631. Centroptella (Chopralla) pusilla, larva. 626, abdominal tergum IX; 627, subimaginal gonostyli crumpled under larval cuticle; 628, labrum; 629, labrum according to original description (Müller-Liebenau 1984a: fig. 5a) with presumable basal margin added with red line; 630, paraprocts; 631, posterior margin of abdominal tergum X. Abbreviations: gs1–gs3, segments of gonostyli; pgs, larval protogonostylus; usg, unistyliger.