Labiobaetis sulawesiensis, 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

2. Labiobaetis sulawesiensis sp. nov. Figures 4 , 5 , 47b , 54a

Diagnosis.

Larva. Following combination of characters: A) dorsal surface of labrum with submarginal arc of 1 + 5 long, simple setae; B) labial palp segment II with an elongated thumb-like distomedial protuberance, segment III conical; C) fore femur rather broad, length ca. 3 × maximum width, dorsal margin with a row of ca. ten curved, spine-like setae; D) paraproct distally not expanded, with ca. 21 stout marginal spines.

Description.

Larva ( Figs 4 , 5 , 47b ). Body length 4.7 mm; antenna approximately twice as long as head length.

Colouration. Head, thorax, and abdomen dorsally brown, head and thorax with bright median, dorsal suture, thorax with pattern as in Fig. 47b , abdominal segments I, V, VI, IX, and X bright, segment IV partly bright. Head, thorax, and abdomen ventrally light brown, abdominal segments VII and VIII dark brown, legs light brown, femur with a distomedial brown spot, caudal filaments light brown, with a dark brown band at 2/3 of cerci.

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

Labrum ( Fig. 4a ). 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 + 5 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. 4b, 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 slightly convex, with minute denticles. Tuft of setae at apex of mola present.

Left mandible ( Fig. 4d, e ). 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 slightly convex. 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. 4f ). Lingua approx. as long as superlingua. Lingua longer than broad; medial tuft of stout setae well developed, short; distal half not expanded. Superlingua straight; lateral margin rounded; fine, long, simple setae along distal margin.

Maxilla ( Fig. 4g ). 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 five medium to long simple setae. Maxillary palp 1.3 × 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; apex of last segment constricted, without excavation at inner distolateral margin.

Labium ( Fig. 4h ). 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, pectinate setae; outer margin with six spine-like setae; ventral surface with short, fine, simple and short, spine-like setae. Paraglossa sub-rectangular, curved inward; apex rounded; with three rows of long, robust, distally pectinate setae in apical area and two medium, simple setae in anteromedial area; dorsally with a row of four long, spine-like setae near inner margin. Labial palp with segment I 0.8 × length of segments II and III combined. Segment I with fine, simple setae along margins. Segment II with elongated, thumb-like distomedial protuberance; distomedial protuberance 0.7 × width of base of segment III; inner and outer margin with short, fine, simple setae; dorsally with a row of five long, spine-like, simple setae near outer margin. Segment III conical; apex slightly pointed; length 1.1 × width; ventrally covered with short and medium spine-like, simple setae and short, fine, simple setae.

Hind wing pads absent ( Fig. 5g ).

Foreleg ( Fig. 5a, b ). Ratio of foreleg segments 1.2:1.0:0.6:0.2. Femur. Length ca. 3 × maximum width. Dorsal margin with a row of ca. ten curved, spine-like setae; length of setae 0.16 × 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. Tibia. Dorsal margin with a row of curved, spine-like setae; on apex one longer, spine-like, apically rounded seta. Ventral margin with a row of curved, spine-like setae, on apex several spine-like, bipectinate setae and a tuft of fine, simple setae. Anterior surface scattered with stout, lanceolate setae. Patellotibial suture present on basal 2/3. Tarsus. Dorsal margin with a row of short, curved, spine-like setae, on apex fine, simple setae. Ventral margin with a row of curved, spine-like setae. Tarsal claw with one row of 12-13 denticles; distally pointed; with 4-5 stripes; subapical setae absent.

Tergum ( Fig. 5c ). Surface with irregular rows of U-shaped scale bases and scattered fine, simple setae. Posterior margin of tergum IV with triangular spines, medially longer than wide, laterally shorter and approx. as long as wide.

Gills ( Fig. 5d ). Present on segments I–VII. Margin with small denticles intercalating fine simple setae. Tracheae extending from main trunk to inner and outer margins. Gill I ca. 1/2 length of segment II. Gill IV as long as length of segments V and 2/3 VI combined. Gill VII little longer than length of segment VIII.

Paraproct ( Fig. 5e ). Distally not expanded, with ca. 21 stout marginal spines. Surface scattered with U-shaped scale bases, fine, simple setae and micropores. Cercotractor with numerous small marginal spines.

Etymology.

Refers to the island Sulawesi, where the specimens were collected.

Distribution.

Indonesia: Sulawesi.

Biological aspects.

The specimens were collected at an altitude of 660 m.

Type-material.

Holotype. Larva (on slide, GBIFCH 00235812), Indonesia, Sulawesi Tengah, Palu-Lake Lore, stream, 660 m, 01.IX.2011, 01°11.75'S, 120°10.20'E, M. Balke leg. (SUL012). Temporary deposited in MZL before finally housed in MZB. Paratypes. 2 larvae (1 on slide, GBIFCH 00592206, deposited in MZL; 1 in alcohol, GBIFCH 00515354, deposited in ZSM), same data as holotype.

Figures

Figure 4. Labiobaetis sulawesiensis 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 5. Labiobaetis sulawesiensis sp. nov., larva morphology: a Foreleg b Fore claw c Tergum IV d Gill IV e Paraproct f Scape g Metanotum.

Figure 47. Habitus, larvae, dorsal view: a Labiobaetis batakorum sp. nov. b Labiobaetis sulawesiensis sp. nov. c Labiobaetis sumbensis sp. nov. d Labiobaetis roulade sp. nov.

Figure 54. Distribution of Labiobaetis in Indonesia.