Labiobaetis pilosus, Kaltenbach, Thomas & Gattolliat, Jean-Luc, 2019

Kaltenbach, Thomas & Gattolliat, Jean-Luc, 2019, The tremendous diversity of Labiobaetis Novikova & Kluge in Indonesia (Ephemeroptera, Baetidae), ZooKeys 895, pp. 1-117 : 1

19. Labiobaetis pilosus sp. nov. Figures 33 , 34 , 50b , 54b

Diagnosis.

Larva. Following combination of characters: A) dorsal surface of labrum with submarginal arc of 1 + 6-8 long, simple setae, the first two setae after the central seta are closely together; B) right mandible with a pronounced hump between prostheca and mola; C) labial palp segment II with a thumb-like distomedial protuberance, segment III conical; D) maxillary palp segment II large and bent inwards, much longer than segment I; E) fore femur rather broad, length ca. 3.4 × width, dorsal margin with a row of 12-16 curved, spine-like setae and many spine-like apically rounded setae along margin; F) paraproct distally not expanded, with ca. 21 stout marginal spines.

Description.

Larva ( Figs 33 , 34 , 50b ). Body length 6.7 mm; antenna approximately 2.5 × as long as head length.

Colouration. Head, thorax, and abdomen dorsally brown, head and thorax with bright median, dorsal suture, abdominal segments with pattern as in Fig. 50b , forewing pads with bright striation. Head, thorax, and abdomen ventrally brown, abdominal segment X light brown, legs light brown, dorsal margin of femur brown, caudal filaments light brown and with a dark brown band at 1/3 of cerci.

Antenna with scape and pedicel subcylindrical, without distolateral process at scape; flagellum with lanceolate spines and fine, simple setae on apex of each segment.

Labrum ( Fig. 33a ). Rectangular, length 0.7 × maximum width. Distal margin with medial emargination and a small process. Dorsally with medium, fine, simple setae scattered over surface; submarginal arc of setae composed of 1 + 6-8 long, simple setae. Ventrally with marginal row of setae composed of lateral and anterolateral long, feathered setae and medial long, bifid, pectinate setae; ventral surface with six short, spine-like setae near lateral and anterolateral margin.

Right mandible ( Fig. 33b, c ). Incisors fused. Outer and inner sets of denticles with 4 + 3 denticles and one minute intermediate denticle. Inner margin of innermost denticle with a row of thin setae. Prostheca robust, apically denticulate. Margin between prostheca and mola with a pronounced hump and minute denticles on margin of hump. Tuft of setae at apex of mola present.

Left mandible ( Fig. 33d, e ). Incisors fused. Outer and inner sets of denticles with 3 + 3 denticles. Prostheca robust, apically with small denticles and comb-shaped structure. Margin between prostheca and mola slightly convex, with minute denticles toward subtriangular process. Subtriangular process long and slender, above level of area between prostheca and mola. Denticles of mola apically constricted. Tuft of setae at apex of mola present.

Both mandibles with lateral margins almost straight. Basal half with fine, simple setae scattered over dorsal surface.

Hypopharynx ( Fig. 33f ). Lingua approx. as long as superlingua. Lingua longer than broad; medial tuft of stout setae well developed; distal half laterally expanded. Superlingua straight; lateral margin rounded; fine, long, simple setae along distal margin.

Maxilla ( Fig. 33g ). Galea-lacinia with one simple, robust apical seta under crown. Inner dorsal row of setae with three denti-setae, distal denti-seta tooth-like, middle and proximal denti-setae slender, bifid and pectinate. Medially with one bipectinate, spine-like seta and five long, simple setae. Maxillary palp 1.6 × as long as length of galea-lacinia; two segmented; palp segment II 1.4 × length of segment I; setae on maxillary palp fine, simple, scattered over surface of segments I and II, very dense on segment II; apex of last segment slightly pointed, with excavation at inner distolateral margin.

Labium ( Fig. 33h ). Glossa basally broad, narrowing toward apex; shorter than paraglossa; inner margin with nine or ten spine-like setae, distalmost seta much longer and less robust than other setae; apex with two long and one medium, robust, pectinate setae and one short, robust seta; outer margin with 5-7 spine-like setae increasing in length distally; ventral surface with short, fine, simple, scattered setae. Paraglossa sub-rectangular, curved inward; apex rounded; with three rows of long, robust, distally pectinate setae in apical area; outer margin with row of three long, spine-like setae and 4-7 medium, simple setae in anteromedial area; dorsally with a row of 4-5 long, spine-like setae near inner margin. Labial palp with segment I 0.6 × length of segments II and III combined. Segment I ventrally with short, fine, simple setae. Segment II with thumb-like distomedial protuberance; distomedial protuberance 0.6 × width of base of segment III; inner and outer margin with short, fine, simple setae; dorsally with a row of 5-7 medium, spine-like, simple setae near outer margin. Segment III conical; apex slightly truncate; length 1.1 × width; ventrally covered with short, spine-like, simple setae and short, fine, simple setae.

Hind wing pads minute.

Foreleg ( Fig. 34 a–c ). Ratio of foreleg segments 1.2:1.0:0.5:0.2. Femur. Length ca. 3 × maximum width. Dorsal margin with a row of 12-16 curved, spine-like setae and many spine-like, apically rounded setae along margin; length of setae 0.19 × maximum width of femur. Apex rounded; with one pair of curved, spine-like setae and some short, stout setae. Many stout, lanceolate setae scattered along the ventral margin, femoral patch absent. Anterior surface covered with fine, simple setae. Tibia. Dorsal margin with a row of curved, spine-like setae; on apex a pair of longer, spine-like setae. Ventral margin with a row of curved, spine-like setae, on apex several stout, partly bipectinate setae and a tuft of fine, simple setae. Anterior surface scattered with stout, lanceolate setae and covered with fine, simple setae. Patellotibial suture present on basal 1/2. Tarsus. Dorsal margin with a row of short, spine-like setae and fine, simple setae. Ventral margin with a row of curved, spine-like setae. Anterior surface covered with fine, simple setae. Tarsal claw with one row of 11-14 denticles; distally pointed; with five stripes; subapical setae absent.

Tergum ( Fig. 34d ). Surface with irregular rows of U-shaped scale bases and scattered fine, simple setae. Posterior margin of tergum IV with triangular spines, approx. as long as wide.

Gills ( Fig. 34e ). Present on segments II–VII. Margin with small denticles intercalating fine simple setae. Tracheae extending from main trunk to inner and outer margins. Gill IV as long as length of segments V and 2/3 VI combined. Gill VII as long as length of segments VIII and 1/3 IX combined.

Paraproct ( Fig. 34f ). Distally not expanded, with 18-23 stout marginal spines. Surface scattered with U-shaped scale bases and fine, simple setae. Cercotractor with numerous small marginal spines.

Etymology.

Refers to the many fine, dense hairs on the legs and the mouthparts.

Distribution.

Indonesia: Sulawesi.

Biological aspects.

The specimens were collected at altitudes of 660 m and 1,600 m.

Type-material.

Holotype. Larva (on slide, GBIFCH 00592201), Indonesia, Sulawesi Tengah, Lake Lore, 1,600 m, 01.IX.2011, 01°19.58'S, 120°18.67'E, M. Balke leg. (SUL013). Temporary deposited in MZL before definitely housed in MZB. Paratypes. 31 larvae (1 on slide, GBIFCH 00592202, 28 in alcohol, GBIFCH 00515359, GBIFCH 00657738, GBIFCH 00657734, deposited in MZL; 2 in alcohol, GBIFCH 00515355, GBIFCH 00515356, deposited in ZSM), same data as holotype; 7 larvae (3 on slides, GBIFCH 00592203, GBIFCH 00592204, GBIFCH 00592205, deposited in MZL; 4 in alcohol, GBIFCH 00515357, GBIFCH 00515358, deposited in ZSM), Indonesia, Sulawesi Tengah, Palu-Lake Lore, stream, 660 m, 01.IX.2011, 01°11.74'S, 120°10.20'E, M. Balke leg. (SUL012).

Figures

Figure 33. Labiobaetis pilosus sp. nov., larva morphology: a Labrum b Right mandible c Right prostheca d Left mandible e Left prostheca f Hypopharynx g Maxilla h Labium.

Figure 34. Labiobaetis pilosus sp. nov., larva morphology: a Foreleg b Foreleg setation on surface of femur, tibia and tarsus c Fore claw d Tergum IV e Gill IV f Paraproct g Metanotum.

Figure 50. Habitus, larvae, dorsal view: a Labiobaetis paranumeratus sp. nov. b Labiobaetis pilosus sp. nov. c Labiobaetis seramensis sp. nov. d Labiobaetis wahai sp. nov.

Figure 54. Distribution of Labiobaetis in Indonesia.