Indocloeon (Hindocloeon) continentale Kluge & Suttinun 2020, sp. n.
Creators: name: Kluge, Nikita J.
name: Suttinun, Chanaporn
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Ephemeroptera
Baetidae
Indocloeon
Indocloeon continentale

description: Indocloeon (Hindocloeon) continentale sp. n.
(Figs 56–102, 106–108)
? Genus No. 1 sp. 1: Müller-Liebenau 1984: 270 (larva).
Etymology. This is the first formally described species of Indocloeon s. l. from continental Asia; all formerly described species are known from islands.
Material examined. Holotype: L-S-I ♂ {specimen [VIII] (7) 2015}: THAILAND, Kanchanaburi Province, Si Sawat District, Erawan Waterfall, 14°22’13”N 99°08’44”E, 4.II.2015, coll. N. Kluge & L. Sheyko (ZIN). Paratypes: the same locality, date and collectors, 20 S-I ♂, 2 I ♂, 19 S-I ♀, 1 I ♀ (ZIN); the same locality, 9.XI.2018, coll. C. Suttinun: 2 larvae (ZMKU). Narathiwat Province, Waeng District, Ai Sae, 05°47’43”N 101°59’56”E, alt. 64 m, 22.IV.2018, coll. C. Suttinun: 12 larvae (ZMKU), 2 larvae (MZL). Specimens presumably determined: INDIA, Kerala State, Erumeli, River Koratty, 18–21.I.2016, coll. N. Kluge & L. Sheyko: 2 S ♂, 2 S ♀ (ZIN).
Descriptions. Larva. CUTICULAR COLOURATION (Figs 56–59). Head dorsally brown with lighter ocher median stripe. Thoracic terga and pleura brown, sterna lighter ocher. Legs light ocher with darker brown cross bands on distal part of femur and on proximal part of tibia. Abdominal terga I–IX dorsally nearly uniformly brown, sterna lighter ocher; abdominal segment X entirely light ocher. Cerci and paracercus uniformly light ocher.
Hypodermal Colouration. Not expressed.
Shape and setation. Antenna: anterior side of flagellum with pointed denticles at apex of each segment, without enlarged spines (Fig. 68). Setae on dorsal side of labrum: paired submedian seta and paired midway seta [see Hindocloeon (1)] equally slender; submarginal arc consists of 7–9 widened, flat, colourless setae (Fig. 60–62). Left mandible: incisor terminated with 4 denticles, 2nd denticle longest; kinetodontium terminated with 3 denticles, 1st denticle longest; margin between prostheca and mola with tuft of setae directed toward mola; mola without setae on proximal angle (Fig. 64) [see Hindocloeon (2), (3), (4)]. Right mandible: incisor terminated with 4 denticles, 3rd denticle longest [see Hindocloeon (2)]; kinetodontium terminated with 3 denticles, 1st denticle longest; margin between prostheca and mola with tuft of setae; mola with seta(e) on proximal angle (Figs 65–66). Maxillary palp long and slender; all 3 palpomeres of subequal length, with long, fine, simple setae scattered over surface (Fig. 69–70) [see Hindocloeon (5)]. Labial palp with 2nd segment moderately long; its medio-apical projection apically rounded (Fig. 71–73) [see Hindocloeon (7)]. Legs slender, with femur parallel-sided (Figs 57, 59, 78–79); in holotype, length of femur: tibia: tarsus: claw (mm) of fore leg 0.63: 0.40: 0.42: 0.12, of middle leg 0.69: 0.45: 035: 0.12, of hind leg 0.70: 0.45: 0.38: 12. Stout setae on outer side of femur non-pectinate, apically blunt (Fig. 81). Apex of femur with 2 stout blunt setae (Fig. 76). Tibia of fore legs with one stout outer-apical seta, without other stout setae on outer margin (Fig. 76); tibiae of middle and hind legs with undetermined number (4–6 in holotype) of stout setae along outer margin, all being smaller than outer-apical seta of fore tibia (Fig. 77) [see Hindocloeon (8)]. Claw with 2 rows of denticles; in each row 2 most distal denticles larger than others (Fig. 80). Hind margin of tergum I lacking denticles; hind margin of each tergum II–X with regular row of triangular pointed denticles; denticles gradually elongated from fore to hind terga, so that on tergum II each denticle as long as its width, on tergum IX denticles twice longer; on all terga (including tergum IX) row of denticles not interrupted medially (Figs 85–88). Hind margins of sterna I–III lack denticles; sternum IV with very short denticles; other sterna with pointed denticles gradually becoming longer and narrower from sternum V to sternum IX (Figs 82–83); on sterna V–VII denticles partly fused basally (Fig. 82). Scales on abdominal terga and sterna blunt and short. Each segment of cercus with regular row of short denticles; each 2nd or each 4th segment with elongated spine-like denticles on lateral side (Fig. 89). For other characters see diagnosis of Hindocloeon above and diagnosis of Indocloeon s. l. (Kluge 2012 and above).
Subimago. Cuticular colouration (Fig. 91). Cuticle nearly entirely colourless. Wings light.
Hypodermal colouration. As in imago (see below).
Male imago (Fig. 93). Head pale ocher. Antennae pale; distal part of scapus with hypodermal pigmented spots on lateral and median sides; distal part of pedicellus with hypodermal pigmented spots on lateral and median sides (Fig. 92) [see Hindocloeon (9)]. Turbinate eyes high, orange; facetted surface bordered by narrow lighter ring. Pronotum from pale ocher to brown. Mesonotum brown with sublateroscutum and scutellum white. Lateral sides of thorax ocher with white and brown markings; ventral side pale ocher. Legs pale ocher. In paratype, length of femur: tibia: tarsomeres (mm) of fore leg 0.77: 1.05: 0.04: 0.27: 0.18: 0.14: 0.12 (in subimago 0.63: 0.63: 0.04: 0.22: 0.17: 0.12: 13) of middle leg 0.70: 0.68: 0.16: 0.07: 0.03: 0.10 (same in subimago), of hind leg 0.70: 0.68: 0.16: 0.07: 0.04: 0.12 (same in subimago). Wings colourless, all veins pale; pterostigma with 3–4 cross veins; marginal intercalaries short (as in Fig. 96). Abdominal segments I–VII translucent and whitish, with dark lateral tracheal trunks; abdominal segment I with pair of dark brown hypodermal lateral spots just ventrad of metathoracic postnotum [see Hindocloeon (10)]; terga VIII–X reddish-brown medially, with white lateral parts. Abdominal sterna VIII–IX and gonostyli pale ocher, penis little darker. Cerci whitish.
Genitals (Fig. 101). Unistyligers projected caudally. Proximal (1st+2nd) segment of gonostylus slender, basally swollen; distal (3rd) segment nearly straight. Gonovectes with movably articulated distal portions [see Hindocloeon (14)].
Female imago (Figs 96–97). Head pale ocher with white. Antennae as in male (see above). Pronotum pale ocher with three pairs of small, contrasting, brown hypodermal spots on lateral parts: triangular anterior, triangular postero-median and oval postero-lateral ones. Mesothorax pale ocher with small brown hypodermal spots on pleura. Legs pale ocher. Wings as in male (see above). Abdomen pale ocher, with dark lateral tracheal trunks; segment I with pair of brown hypodermal lateral spots ventrad of metathoracic postnotum; each segment II–VII with following contrasting brown hypodermal maculae: tergum with unpaired T-form macula (widest posteriorly—Fig. 96); lateral sides of tergum with pair of longitudinal stripes slightly arched by convexity dorsally; lateral sides of sterna with pair of longitudinal maculae of peculiar shape (Figs 97, 100).
Egg (Figs 106–108). Oval, about 0.15 mm length. Chorion roughly wrinkled.
Dimension. Fore wing length (and approximate body length) 3–4 mm.
Comparison. The larva of I. (H.) continentale sp. n. differs from species other than I. (H.) spathasetis by the constant presence of two enlarged denticles in each of two rows on the claw. In contrast to I. (H.) spathasetis, larval legs are slender (Figs 78–79); the midway seta between the submedian seta and submarginal arc of the labrum is not widened (Figs 60–61); and the antenna has no elongated spines (Fig. 68). Differences between male and female imagines of I. (H.) continentale sp. n. and other species are given in the keys (see above).
Discussion. Specimens from southern India (Erumeli) are presumably determined as belonging to I. (H.) continentale sp. n. based on the characteristic hypodermal colouration of the female pronotum and abdomen, which are identical in imaginal and subimaginal stages (Figs 98–100).
The larva from west Malaysia described by Müller-Liebenau (1984) as «Genus No. 1 sp. 1» is presumably determined as belonging to I. (H.) continentale sp. n. based on the presence of two enlarged denticles in each of two rows on the claw (Müller-Liebenau 1984: fig. 14k).
description: Published as part of Kluge, Nikita J. & Suttinun, Chanaporn, 2020, Review of the Oriental genus Indocloeon Müller-Liebenau 1982 (Ephemeroptera: Baetidae) with descriptions of two new species, pp. 451-484 in Zootaxa 4779 (4) on pages 468-478, DOI: 10.11646/zootaxa.4779.4.1, http://zenodo.org/record/3839329