Cloeodes vibratorius, Kluge, 2017

Kluge, Nikita J., 2017, Contribution to the knowledge of Cloeodes Traver 1938 (Ephemeroptera, Baetidae), Zootaxa 4319 (1), pp. 91-127 : 96-104

Cloeodes vibratorius sp. n.

(Figs 1–43, 145)

Etymology. The adjective vibratorius refers to the unusual respiratory movements of larva.

Material examined. Holotype: L-S-I ♂ {specimen [ XLII](27)2013}, PERU, Region Junin, Satipo Province, Puerto Prado , Rio Meritori , 11°09'S, 74°16'W, 15.IX.2013, coll. N. Kluge & L. Sheyko. Paratypes: the same locality, 4 L-S-I ♂, 2 L-S ♂, 4 L-S-I ♀, 2 L-S ♀, 6 larvae.

Descriptions. Larva. CUTICULAR COLORATION. Frons between ocelli more or less colored with brown; remainder head from colorless to brown. Pronotum of immature larva colorless with posterior margin bordered by dark brown (Fig. 4), before molt cuticle of pronotum gets characteristic brown coloration (Figs 3, 5). Mesonotum in immature larva colorless with small brown markings; before molt cuticle of mesonotum becomes brown with extensive darker brown maculation; cuticle of fore protopteron become brown with lighter stripes along veins (Figs 5). Metanotum with posterior margin bordered by brown (Figs 1, 2, 4); before molt cuticle of mesonotum becomes entirely brown (Fig. 3). Pleurite of prothorax and episterna of mesothorax and metathorax with brown markings (Fig. 2); before molt their cuticle become entirely brown; remainder thoracic pleura and sterna always colorless. On all legs femur colorless with longitudinal brown maculae at middle; tibia colorless with diffusive spot(s) proximad or/and distad of patella-tibial suture; tarsus and claw brown ( Figs 21–23 ). Abdominal terga light brown, partly colorless, with following dark brown markings (Figs 1–4): terga I–VII with posterior margin narrowly bordered by dark brown; tergum II with brown transverse stripe adjacent to anterior margin and pair of oblique submedian stripes arising from this transverse stripe and diverging posteriorly; tergum III with brown markings lighter, or smaller, or absent; tergum IV with brown markings less expressed or absent; terga V and VI with intensive markings similar to tergum II, sometimes entirely darkened; tergum VII with markings less expressed; terga VIII and IX without large markings, tergum X with brown posterior part. Abdominal sterna colorless, with brown markings on some posterior segments; paraprocts brown ( Fig. 19 ). Caudalii with diffusive, but intensive coloration: proximal part dark, middle part light, apex dark (Figs 1–4).

HYPODERMAL COLORATION. Pair of dark brown maculae on abdominal tergum I and sometimes small maculae on some other abdominal terga (as in imago—Fig. 30).

SHAPE AND SETATION. Frontal suture pointed, rectangular; face relatively long; in female larva eyes brought together ( Fig. 6 ). Labrum widest at base, with pair of submedian long setae and 2 pairs of sublateral long setae ( Fig. 12 ). Prostheca of left mandible with 3 blunt processes and 3 pointed processes; median margin of left mandible proximad of prostheca straight or slightly convex, smooth ( Fig. 9 ). Prostheca of right mandible directed medially-proximally, bifurcate, with longest branch directed proximally; median margin of right mandible proximad of prostheca straight or slightly convex, smooth or with serration, without seta-like processes ( Figs 10, 11 ). Stipes of maxilla proximally with 4–6 setae on ventro-medial side. Maxillary canines and distal dentiseta stout; distal dentiseta widened, with apex somewhat hooked toward canines ( Fig. 8 ). Maxillary palp about as long as maxilla, 2-segmented ( Fig. 7 ). Labium with glossae and paraglossae subequal, both narrowed apically ( Fig. 14 ). Glossa with 6–8 setae in dorso-lateral row; ventrally with irregularly arranged setae in proximal part and 5–10 setae forming ventro-median row. Paraglossa with latero-apical setae forming one regular row and few (2–4) setae just dorsad of it; with 7–10 setae in ventro-median row; with 3–4 setae in dorso-median row. Distal segment of labial palp not widened apically, with median margin subequal to lateral margin ( Fig. 13 ).

All thoracic terga without protuberances. Metanotum without vestiges of hind protoptera ( Fig. 22 ). Fore legs longest, middle legs shorter and hind legs shortest; on fore leg tarsus much longer than tibia, on middle and hind legs tarsus subequal to tibia; claws not elongated, much less than half of tarsal length ( Tables 2, 3; Figs 21–23 ). Femur parallel-sided, with outer margin straight and inner margin slightly convex; apical projection equally short on femora of all leg pairs ( Fig. 16 ). Outer side of femur with row of 3–6 small spatulate setae; apical projection with 2 such setae ( Fig. 16 ). Inner and dorsal side of femur with few stout setae, which are several times smaller than setae on dorsal side. Patella-tibial suture and proximal arc of long setae with contiguous sockets equally developed on tibiae of all leg pairs ( Fig. 16 ). Inner margin of tibia with irregular small stout pointed setae, apically with 2 larger setae; outer-apical seta blunt, reaching apex of tibia ( Fig. 16 ). Dorsal side of each tarsus with long fine setae situated irregularly and partly forming two longitudinal rows ( Fig. 17 ). Claw shorter than 1/2 of tarsus length ( Figs 21–23 ).

Scales on abdominal terga and sterna numerous, short, semicircular, colorless and delicate. Posterior margin of abdominal tergum I smooth, without denticles; posterior margins of terga II–X with regular long pointed brown denticles; on tergum IX, portion of posterior margin behind pair of submedian setae, lacks denticles and projected backward ( Fig. 18 ). Posterior margins of abdominal sterna I–III smooth; posterior margins of sterna IV–VIII with regular pointed denticles, shorter and lighter than denticles on terga ( Fig. 19 ). Each sternum II–VI with pair of regular transverse arched rows of long, fine, simple (not furcate) setae with closely contiguous sockets ( Fig. 20 ). Tergalii wide; tergalius I relatively short and wide, widest at proximal half, with costal margin nearly straight and anal margin sharply convex; tergalii II–IV also widest at proximal half ( Figs 37–43 ). All tergalii with ribs only on proximal parts of costal and anal margins, without middle rib. Margins bearing costal and anal ribs smooth (not serrated); margins free of ribs slightly notched, with small seta in each notch. Paraprocts with anterior median apodeme long, thickened and pigmented; each paraproct with 7–8 long pointed denticles on posterior margin, with dense scales as on sterna and terga ( Figs 15 , 19 ). Caudalii with especially long and dense swimming setae; each swimming seta gradually changes from long dark proximal part to short colorless delicate apical part. Ventral and dorsal side of paracercus and lateral sides of cerci in middle part with one or several long pointed denticles on each 2nd segment.

DEVELOPING MALE GENITALS. In last larval instar, developing subimaginal gonostyli folded under larval cuticle in « Nigrobaetis -type» pose, with 2nd segment bent by convexity medially, and 3rd segment directed caudally ( Fig. 33 ).

RESPIRATORY MOVEMENTS. Larva makes energetic rhythmical dorso-ventral vibrations by the whole body, raising it dorsally quicker than lowing ventrally. Some individuals demonstrate ability to make respiratory vibrations by tergalii.

Subimago. CUTICULAR COLORATION. Cuticle colorless with contrasting dark brown markings on thoracic terga and pleura. Head colorless, only antennae slightly tinged with pale brownish. Pronotum colorless. Mesonotum at most colorless, with contrasting dark brown markings on certain sutures ( Fig. 24 ). Thoracic pleura at most colorless, with certain sclerites contrastingly dark brown; lateropostnotal crest forming wide contrasting brown macula of characteristic shape ( Fig. 25 ). Wing cuticle nearly colorless. Legs at most colorless, tarsi slightly tinged with pale brownish; distal margin of each tarsal segment narrowly bordered by brown. Abdominal terga and sterna entirely colorless. Styliger colorless, bordered with brownish; gonostyli colorless. Cerci entirely colorless.

HYPODERMAL COLORATION. As in imago.

TEXTURE. On all legs of both sexes last tarsal segment entirely covered by pointed microlepides; other tarsal segments at most part covered by blunt microlepides, apically by pointed microlepides ( Table 1).

Tarsal spines of subimago and imago. Tarsus of fore leg in male and female without apical spines. Tarsus of middle and hind leg of both sexes with 1 apical spine on initial 3rd tarsomere (next after 1st+2nd tarsomere) ( Table 1).

fore leg ♂ fore leg ♀ mid & hind leg Texture of tarsal segments in subimago: U, tarsomere covered mainly by blunt microlepides (pointed microlepides can be present only on apex of this tarsomere); Y, whole tarsomere covered by pointed microlepides. Apical spine: +, present; –, absent.

Imago, male. COLORATION ( Figs 30, 31 ). Head pale ocher. Turbinate eyes either entirely orange, or with orange stem and yellow facetted surface. Thorax pale ocher, with paired frame-shaped brown macula including antelateroparapsidal scutal suture; mesothoracic postscutellum contrastingly dark brown (cuticular coloration). Wing membrane colorless, veins pale ocher or colorless, basal part of subcostal vein and costal brace with brown markings. Femora of all legs ocher, with following hypodermal coloration: subapical irregular orange band, apical part irregularly shaded with brown; fore femur with or without longitudinal orange spot at middle and/or longitudinal brownish stripes ( Fig. 28, 29 ). Tibiae of all legs pale ocher, with or without hypodermal orange coloration on inner side. Tarsi of all legs pale ocher, on fore leg cuticle of first segment can be tinged with brownish. Claws brown. Abdomen nearly colorless, whitish, with following hypodermal markings: tergum I always with pair of contrasting black spots; terga II, III, and V–VII with or without pair of narrow light brown transverse stripes near posterior margin; stripes of one segment can be either separated, or connected by fine transverse line; terga VII–IX with or without diffusive light orange median macula; some parts of lateral tracheal trunks colored with light brown ( Figs 30, 31 ). Cerci entirely colorless, whitish.

STRUCTURE. Turbinate eyes with wide facetted surface ( Fig. 31 ). Pterostigma with 3–6 complete and incomplete oblique veins; two marginal intercalaries nearly in each space (except for few posterior ones), length of most intercalaries less than distance between adjacent longitudinal veins ( Fig. 32 ). Hind wing absent. Middle and hind tarsus long (about 0.7–0.8 of tibia length), its 1st+2nd segment subequal or longer than 3rd, 4th and 5th segments together ( Table 2). Genitals as in Figs 35–36 : unistyligers wide basally, surface between them striated; gonovectes shallowly bent; median sterno-styligeral muscle slender, consists of pair of separate bunches, which are convergent V-shaped.

Imago, female. COLORATION. Similar to in male. Veins of wings brown, darker than in male ( Fig. 26 ).

Structure. Eyes relatively large, elevated above head surface ( Figs 26–27 ). Wing venation as in male, with 2 marginal intercalaries nearly in each space (except for few posterior ones) (as in Fig. 32 ). Leg proportions similar to that of male ( Table 3).

Egg. Widely oval, 0.1 mm length. Chorion thin, irregularly crumpled, without regular relief ( Fig. 145 ).

Dimension. Fore wing length: male 6 mm; female 7 mm.

Distribution. Known from one locality in Peru.

Comparison. Larva of C. vibratorius sp. n. differs from other species by great proximal-posterior widening of first tergalius ( Fig. 37 ). Its cuticular coloration of abdomen is characteristic and includes dark submedian oblique stripes on terga II, V and VI (Figs 1–4); from C. barituensis , whose larvae have similar abdominal coloration, C. vibratorius differs by presence of submedian oblique stripes on abdominal tergum II, which are more intensive than stripes on tergum III.

Subimago of C. vibratorius sp. n. differs from other species by colorless cuticle with few contrasting dark brown maculae on pterothorax terga and pleura only ( Figs 24–25 ).

Among two-winged species of Cloeodes , female imago and subimago of C. vibratorius sp. n. differs from C. barituensis , C. maracatu , C. redactus , C. maculipes , C. caraibensis , C. superior and C. inferior by presence of 2 marginal intercalaries in each space. Male and female imagoes and subimagoes of C. vibratorius sp. n. differ from other species by characteristic pale coloration with contrasting black postscutellum and pair of contrasting black spots on first abdominal segment ( Figs 26, 31 ).

Larva of C. vibratorius sp. n. differs from other mayfly larvae observed by me in living condition, by unusual respiratory movements.

Figures

FIGURES 18 – 25. Cloeodes vibratorius sp. n. 18 – 23, larval exuviae: 18, tergum IX; 19, paraprocts; 20, portion of sternum IV with setal row; 21, fore leg; 22, middle leg and half of metanotum; 23, hind leg; 24 – 25, subimaginal exuviae: 24, left half of mesonotum; 25, postsubalar sclerite and lateropostnotal crest (21 – 23, holotype).

FIGURES 6 – 12. Cloeodes vibratorius sp. n., larva. 6, head of female larva; 7, maxilla; 8, apex of maxilla; 9 – 11, left and right mandibles; 12, labrum (apical setae not shown) (10, 12, holotype). Abbreviations: ds 1, ds 2, ds 3, dentisetae.

FIGURES 13 – 17. Cloeodes vibratorius sp. n. 13, labial palp; 14, labium (left half in ventral view with muscles shown by interrupted lines; right half in dorsal view); 15, paraprocts; 16, tibia of fore leg, anterior view (seta and suture on opposite side shown by interrupted lines; only two setae of proximal arched row are shown); 17, tarsus of hind leg, view from outer side (13, holotype).

FIGURES 37 – 57. Cloeodes spp., tergalii. 37 – 43, tergalii I – VII of Cloeodes vibratorius sp. n.; 44 – 57, tergalii I – VII of two individuals of Cloeodes redactus. For all three individuals vertical line corresponds to length of abdominal segment IV.

FIGURES 32 – 36. Cloeodes vibratorius sp. n. 32, fore wing of male; 33, subimaginal gonostyli developing under larval cuticle; 34, exuviae of subimaginal genitals; 35, genitals of male imago (gonovectes shown by interrupted line; at right half gonovectal and gonostylar muscles shown by interrupted lines; median styligeral muscle shown by interrupted lines, areas of anterior attachment of median paraproctal muscles shown by dotted lines); 36, gonostylus (32, 34 – 35, holotype). Abbreviations: 1, 2, 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); m. sg, median sterno-styligeral muscle; usg, unistyliger.

FIGURES 26 – 31. Cloeodes vibratorius sp. n. 26 – 27, female imago; 28 – 31, male imago: 28, femur of fore leg; 29, femur of hind leg; 30, abdominal terga and sterna spread on slide; 31, lateral view. Abbreviations: I – X, abdominal segments I – X.

FIGURES 145 – 146. Eggs. 145, Cloeodes vibratorius sp. n.; 146, Cloeodes redactus.