Labiobaetis jonasi, 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

27. Labiobaetis jonasi sp. nov. Figures 45 , 46 , 51b, c , 52f , 55a

Diagnosis.

Larva. Following combination of characters: A) dorsal surface of labrum with submarginal arc of 1 + 6 long, feathered setae; B) labial palp segment II with a thumb-like distomedial protuberance, segment III oblong and pointed; C) fore femur rather slender, length ca. 4 × maximum width, dorsal margin with a row of ca. 13 lanceolate, spine-like setae and some submarginal setae; D) mouthparts including maxillary palp and labial palp sclerotized, dark brown; E) paraproct distally not expanded, with 30-36 stout marginal spines.

Description.

Larva ( Figs 45 , 46 , 51b, c , 52f ). Body length 6.8-7.6 mm; antenna approximately 3 × as long as head length.

Colouration. Head, thorax, and abdomen dorsally brown to dark brown, head and thorax with bright median, dorsal suture; thorax and abdomen with bright pattern as in Fig. 51b, c ; forewing pads with dark striation and mature larva additionally with bright striation close to margin. Head, thorax, and abdomen ventrally light brown to dark brown, legs with yellowish and brown pattern as in Fig. 52f , mouthparts including maxillary and labial palp brown. Caudal filaments brown with a darker section in the middle part.

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. 45a, b ). Rectangular, length 0.8 × 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 long, feathered setae. Ventrally with marginal row of setae composed of lateral and anterolateral long, feathered setae and medial long, bifid, pectinate setae; ventral surface with eight short, spine-like setae near lateral and anterolateral margin.

Right mandible ( Fig. 45c, d ). Incisors fused. Outer and inner sets of denticles with 3 + 3 denticles. Inner margin of innermost denticle with a row of thin setae. Prostheca robust, apically denticulate. Margin between prostheca and mola straight. Tuft of setae at apex of mola present.

Left mandible ( Fig. 45e, f ). 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 straight. 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. 45g ). Lingua longer than superlingua. Lingua longer than broad; medial tuft of stout setae well developed, short; distal half laterally expanded. Superlingua straight; lateral margin rounded; fine, long, simple setae along distal margin.

Maxilla ( Fig. 45h ). 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 six long, simple setae. Maxillary palp 1.4 × 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 excavation at inner distolateral margin.

Labium ( Fig. 45i, j ). Glossa basally broad, narrowing toward apex; shorter than paraglossa; inner margin with 9-11 spine-like setae increasing in length distally; apex with two long and one medium, robust setae; outer margin with nine or ten long, spine-like setae increasing in length distally; ventral surface with short, fine, simple setae. Paraglossa sub-rectangular, curved inward; apex rounded; with three rows of long, robust, distally pectinate setae in apical area and a row of four medium, simple setae in anteromedial area; dorsally with a row of six or seven 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 and some short, stout, simple setae at inner margin. 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 eight medium, spine-like, simple setae near outer margin. Segment III oblong; apex slightly pointed; length 1.3 × width; ventrally covered with short, spine-like, simple setae and short, fine, simple setae.

Hind wing pads absent.

Foreleg ( Fig. 46a, b ). Ratio of foreleg segments 1.2:1.0:0.5:0.2, or 1.1:1.0:0.4:0.1. Femur. Length ca. 4 × maximum width. Dorsal margin with a row of ca. 13 spine-like setae and some spine-like setae near margin; length of setae 0.16 × maximum width of femur. Apex rounded; with one pair of spine-like setae and some short, stout setae. Many stout, lanceolate setae scattered along the ventral margin; femoral patch reduced to a few setae. Tibia. Dorsal margin with a row of stout, lanceolate setae and additional stout, lanceolate setae near margin. 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 1/2. Tarsus. Dorsal margin with a row of short, spine-like setae and additional stout, lanceolate setae near margin. Ventral margin with a row of curved, spine-like setae and some spine-like setae near margin. Tarsal claw with one row of 13 denticles; distally pointed; with seven or eight stripes; subapical setae absent.

Tergum ( Fig. 46c ). Surface with irregular rows of U-shaped scale bases and scattered micropores. Posterior margin of tergum IV with triangular spines, longer than wide.

Gills ( Fig. 46d ). 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 as long as length of segment II. Gill IV as long as length of segments V, VI, and 1/4 VII combined. Gill VII as long as length of segments VIII and IX combined.

Paraproct ( Fig. 46e ). Distally not expanded, with 30-36 stout marginal spines. Surface scattered with U-shaped scale bases and micropores. Cercotractor with numerous small marginal spines.

Etymology.

Dedicated to Jonas Gattolliat, son of one of the authors (JLG).

Distribution.

Indonesia: Sumba.

Biological aspects.

The specimens were collected at an altitude of 400 m.

Type-material.

Holotype. Larva (on slide, GBIFCH 00592231), Indonesia, Sumba, Waikelo stream, 400 m, 27.IX.2011, 09°35.74'S, 119°20.41'E, M. Balke leg. (SUA04). Temporary deposited in MZL before definitely housed in MZB. Paratypes. 30 larvae (2 on slides, GBIFCH 00592233, GBIFCH 00592232, 17 in alcohol, GBIFCH 00515352, GBIFCH 00654966, GBIFCH 00654967, deposited in MZL; 11 in alcohol, GBIFCH 00515353, deposited in ZSM), same data as holotype.

Figures

Figure 45. Labiobaetis jonasi 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 j Apex of paraglossa.

Figure 46. Labiobaetis jonasi sp. nov., larva morphology: a Foreleg b Fore claw c Tergum IV d Gill IV e Paraproct f Scape.

Figure 51. Habitus, larvae, dorsal view: a Labiobaetis multus b Labiobaetis jonasi sp. nov. c Labiobaetis jonasi sp. nov. d Labiobaetis paraoperosus sp. nov.

Figure 52. Larvae: a Labiobaetis batakorum sp. nov., ventral view, legs b Labiobaetis sumbensis sp. nov., ventral view, legs c Labiobaetis roulade sp. nov., ventral view, legs d Labiobaetis weifangae sp. nov., ventral view, legs e Labiobaetis gueuningi sp. nov., ventral view f Labiobaetis jonasi sp. nov., ventral view.

Figure 55. Distribution of Labiobaetis in Indonesia.