Labiobaetis itineris, 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

10. Labiobaetis itineris sp. nov. Figures 16 , 17 , 48b , 54b

Diagnosis.

Larva. Following combination of characters: A) dorsal surface of labrum with submarginal arc of 20-23 clavate setae; B) labial palp segment II with a large, thumb-like distomedial protuberance, segment III oblong; C) left mandible without setae at apex of mola; D) fore femur rather broad, length 3.4 × maximum width, dorsal margin with 9-12 curved, spine-like setae; E) tarsus ventrally with a row of stout, bipectinate setae; F) paraproct distally expanded, with ca. 40 stout marginal spines.

Description.

Larva ( Figs 16 , 17 , 48b ). Body length 5.8 mm.

Colouration. Head, thorax, and abdomen dorsally brown, head, and thorax with bright median, dorsal suture, thorax with pattern as in Fig. 48b , forewing pads with bright striation. Head, thorax, and abdomen ventrally light brown, caudal filaments light brown.

Antenna with scape and pedicel subcylindrical, with poorly developed distolateral process at scape; flagellum with lanceolate spines and fine, simple setae on apex of each segment.

Labrum ( Fig. 16a, b ). 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 20-23 long, clavate setae. Ventrally with marginal row of setae composed of anterolateral long, feathered setae and medial long, bifid setae; ventral surface with six short, spine-like setae near lateral and anterolateral margin.

Right mandible ( Fig. 16c, d ). 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 slightly convex, with minute setae. Tuft of setae at apex of mola present.

Left mandible ( Fig. 16e, f ). Incisors fused. Outer and inner sets of denticles with 4 + 3 denticles and one minute intermediate denticle. Prostheca robust, apically with small denticles and comb-shaped structure. Margin between prostheca and mola straight, with minute denticles towards 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 absent.

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

Hypopharynx ( Fig. 16g ). 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. 16h ). Galea-lacinia with two simple, robust apical setae 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 3-4 medium, simple setae. Maxillary palp 1.2 × as long as length of galea-lacinia; two segmented; palp segment II 1.3 × length of segment I; setae on maxillary palp fine, simple, scattered over surface of segments I and II; apex of last segment rounded, with slight excavation at inner distolateral margin.

Labium ( Fig. 16i ). Glossa basally broad, narrowing toward apex; shorter than paraglossa; inner margin with eight spine-like setae increasing in length distally; apex with two long and one medium, robust setae; outer margin with 4-6 long, 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 and three medium, simple setae in anteromedial area; dorsally with a row of four or five long, spine-like setae near inner margin. Labial palp with segment I 0.8 × length of segments II and III combined. Segment I ventrally with short, fine, simple setae. Segment II with broad 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 two long, spine-like, simple setae near outer margin. Segment III oblong; apex rounded; length 1.1 × width; ventrally covered with short, spine-like, simple setae and short, fine, simple setae.

Hind wing pads absent.

Foreleg ( Fig. 17a, b, c, d ). Ratio of foreleg segments 1.2:1.0:0.5:0.2. Femur. Length ca. 3 × maximum width. Dorsal margin with a row of 9-12 curved, spine-like setae; length of setae 0.23 × 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 poorly developed. Tibia. Dorsal margin with a row of stout, lanceolate setae. Ventral margin with a row of short, curved, spine-like setae, on apex two bipectinate, spine-like setae and a tuft of fine, simple setae. Anterior surface scattered with stout, lanceolate setae. Patellotibial suture present on basal 1/3. Tarsus. Dorsal margin bare. Ventral margin with a row of spine-like, bipectinate setae. Tarsal claw with one row of eleven denticles; distally pointed; with four stripes; subapical setae absent.

Tergum ( Fig. 17e ). Surface with irregular rows of U-shaped scale bases and scattered fine, simple setae and micropores. Posterior margin of tergum IV with triangular spines, wider than long.

Gills ( Fig. 17f ). 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 1/2 VI combined. Gill VII as long as length of segments VIII and 1/4 IX combined.

Paraproct ( Fig. 17g ). Distally expanded, with 35-43 stout marginal spines. Surface scattered with U-shaped scale bases and micropores. Cercotractor with numerous small marginal spines.

Etymology.

Refers to travel activities, as the islands Sumbawa and especially Bali are well known for tourism.

Distribution.

Indonesia: Sumbawa and Bali.

Biological aspects.

The specimens were collected at altitudes of 195 m and 860 m.

Type-material.

Holotype. Larva (on slide, GBIFCH 00592225), Indonesia, Bali, Ubud, Sayan, Ayung River, 194 m, 20.IX.2011, 08°29.98'S, 115°14.59'E, M. Balke leg. (BLI015). Temporary deposited in MZL before definitely housed in MZB. Paratypes. 2 larvae (on slides, GBIFCH 00592226, GBIFCH 00592227, deposited in MZL), Indonesia, Sumbawa, Batu Dulang, 10 mins to Tepal, forest stream, 860 m, 16.IX.2011, 08°35.87'S, 117°16.68'E, M. Balke leg. (SUMB08).

Figures

Figure 16. Labiobaetis itineris sp. nov., larva morphology: a Labrum b Seta of the submarginal arc on the dorsal surface of the labrum c Right mandible d Right prostheca e Left mandible f Left prostheca g Hypopharynx h Maxilla i Labium.

Figure 17. Labiobaetis itineris sp. nov., larva morphology: a Foreleg b Fore tibia dorsal seta c Fore tarsus ventral seta d Fore claw e Tergum IV f Gill IV g Paraproct h Scape.

Figure 48. Habitus, larvae, dorsal view: a Labiobaetis weifangae sp. nov. b Labiobaetis itineris sp. nov., without head c Labiobaetis lubu sp. nov. d Labiobaetis pakpak sp. nov.

Figure 54. Distribution of Labiobaetis in Indonesia.