Centroptella (Chopralla) pusilla Müller-Liebenau 1984

Kluge, Nikita J., 2021, Review of Centroptella Braasch & Soldán 1980 (Ephemeroptera, Baetidae), Zootaxa 5054 (1), pp. 1-144 : 130-132

3.5. Centroptella (Chopralla) pusilla Müller-Liebenau 1984

( Figs 626–631 )

Centroptella pusilla Müller-Liebenau 1984a: 94 (larva);

Chopralla pusilla: Waltz & McCafferty 1987a: 183 ;

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

« Cloeodes Sabah -1» (unpublished label).

Material examined. MALAYSIA, Negeri Sabah, Karagasan, Ranau , 6.IX.1994, coll. S.C. Kang: 3 L/S ♂ (other specimens in Entomological Institute in Česke Budejovice ) .

Descriptions.

Larva. CUTICULAR COLORATION: Pronotum and abdominal terga I–VI as figured by Müller-Liebenau (1984a: fig. 11).

HYPODERMAL COLORATION: Unknown.

SHAPE: Labrum short, widest at base and narrowed distally ( Fig. 625 ). 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 ( Müller-Liebenau 1984a: fig. 5e). 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.

Pronotum without protuberances (in contrast to C. ingridae ). Metanotum with vestiges of hind protoptera (in all 6 individuals examined). Forelegs longest, hind legs shortest; on fore and middle legs tarsus (measured on outer side) as long as tibia; on hind legs tarsus slightly shorter than tibia ( Müller-Liebenau 1984a: fig. 5h). 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 1984a: fig. 5h). Claw with two rows of 2–5 denticles in each [see Chopralla (2)] ( Müller-Liebenau 1984a: fig. 5i).

Denticles on posterior margins of abdominal terga and sterna flat (not conic). Terga I–VIII, without denticles; tergum IX with triangular denticles interrupted medially, behind pair of submedian setae ( Fig. 626 ). Posterior projection of abdominal tergum X trapezoid, without denticles or with small denticles on angles only ( Fig. 631 ). Sterna I–IV without denticles; sterna V–VIII with regular, small, pointed, triangular denticles. Posterior margin of sternum IX in male without denticles between protogonostyli ( Fig. 627 ). Paraprocts with thin and colorless antero- median apodeme, with large pointed denticles on posterior margin ( Fig. 630 ).

Tergalius I narrow, elongate-ellipsoid; other tergalii wider, gradually changing in shape from tergalius II to tergalius VII; 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 not large (reaching midlength of next segment), located on every 4th segment and arranged by 1–2 on each side of secondary swimming setal row [see Centroptella s. l. (3)].

SCALES: Scales on pronotum, mesonotum and protoptera very small (with sockets 3–4 mkm and length 4–5 mkm). Femora, tibiae and tarsi densely covered with colorless, short, oval scales (sockets 5–6 mkm). Scales on abdominal terga numerous, elongate, oval, wider than their sockets ( Fig. 626 ). Scales on abdominal sterna, thoracic pleura and metanotum smaller.

STOUT SETAE: Outer side of femur with regular row of 7–13 long, clavate setae and 2 subapical setae of same form ( Müller-Liebenau 1984a: fig. 5h). Inner-anterior side of each femur with small, stout, blunt setae; no longer setae on inner-anterior side of fore femur. Tibia and tarsus with stout setae on inner side. Outer-apical seta of tibia 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 [see Chopralla (1)] ( Müller-Liebenau 1984a: fig. 5h). 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. 604 ). 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 [see Chopralla (4)].

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. 627 ) [see Chopralla (5)].

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

Imago, male. Unknown. Judging by subimaginal leg developed under larval cuticle, tarsus of middle and hind legs with 1 apical spine on initial 3rd tarsomere (next after 1st+2nd tarsomere); sterno-styligeral muscle present [see Chopralla (7)].

Imago, female. Unknown.

Egg. Unknown.

Dimension. Body length about 3.5 mm.

Comments. In the original description, labrum is figured as relatively long, with unusual shape of lateral sides ( Müller-Liebenau 1984a: fig. 5a). Type specimens were kept in Purdue University ( USA), but now are probably missing (L. Jacobus, personal communication). My determination of the specimens examined as C. pusilla is based on the assumption that Müller-Liebenau took the internal arms of labrum for lateral-proximal margins of the labrum ( Figs 628–629 ).

Distribution. Borneo. Selvakumar et al. (2017) erroneously reported C. pusilla from southern India; actually the larvae from India reported by them belong to C. ceylonensis (see above).

Figures

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.

FIGURES 624–625. Centroptella (Chopralla) papuanica sp. n., egg (extracted from holotype).

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 598–606. Centroptella (Chopralla) papuanica sp. n., larval exuviae (holotype). 598, abdomen; 599, pronotum and mesonotum; 600, area of pronotum close to median suture with bifurcate seta corresponding to a on Fig. 14; 601, scale on metanotum with same magnification; 602, abdominal sternum VI and enlarged scales; 603, abdominal sternum IX and enlarged scales; 604, labrum; 605, labium; 606, abdominal terga VIII–IX and enlarged scales.

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.