Labiobaetis seramensis, 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

22. Labiobaetis seramensis sp. nov. Figures 38 , 39 , 50c , 54a

Diagnosis.

Larva. Following combination of characters: A) dorsal surface of labrum with submarginal arc of 1 + 2 long, simple setae; B) labial palp segment II with slender, thumb-like distomedial protuberance; C) maxillary palp approx. as long as length of galea-lacinia; D) fore femur rather broad, length ca. 3 × width, dorsally with a row of ca. 21 curved, spine-like setae on margin; E) posterior margin of tergum IV with triangular spines, wider than long; F) paraproct distally not expanded, with ca. 15 stout marginal spines and a few stout submarginal spines.

Description. Larva ( Figs 38 , 39 , 50c ). Body length 4.8 mm.

Colouration. Head, thorax, and abdomen dorsally brown, head and thorax with bright median, dorsal suture, thorax with bright pattern as in Fig. 50c , forewing pads with darker striation, abdominal segment VI with bright areas as in Fig. 50c , abdominal segments IX and X light brown. Head, thorax, and abdomen ventrally light brown, legs transparent, femur with brown dorsal margin, caudal filaments transparent.

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

Labrum ( Fig. 38a ). Rectangular, length 0.7 × maximum width. Distal margin with medial emargination and a small process. Dorsally with medium, fine, simple setae and a few short, slightly lanceolate setae; submarginal arc of setae composed of 1 + 2 long, simple setae. Ventrally with marginal row of setae composed of 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. 38b, c ). Incisors fused. Outer and inner sets of denticles with 4 + 4 denticles. Inner margin of innermost denticle with a row of thin setae. Prostheca robust, apically denticulate. Margin between prostheca and mola slightly convex. Tuft of setae at apex of mola present.

Left mandible ( Fig. 38d, e ). Incisors fused. Outer and inner sets of denticles with 3 + 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 present.

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

Hypopharynx ( Fig. 38f ). Lingua approx. as long as superlingua. Lingua approx. as broad as long; medial tuft of stout setae well developed, long; distal half not expanded. Superlingua straight; lateral margin rounded; fine, long, simple setae along distal margin.

Maxilla ( Fig. 38g ). 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 long, simple setae. Maxillary palp approx. as long as length of galea-lacinia; two segmented; palp segment II 1.5 × length of segment I; setae on maxillary palp fine, simple, scattered over surface of segments I and II; apex of last segment slightly pointed, with slight excavation at inner distolateral margin.

Labium ( Fig. 38h ). Glossa basally broad, narrowing toward apex; shorter than paraglossa; inner margin with five spine-like setae increasing in length distally; apex with two long and one medium, robust, pectinate setae and one short, robust seta; outer margin with four long, 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 three medium, simple setae in anteromedial area and one fine, simple seta in proximomedial 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 ventrally with short, fine, simple setae. Segment II with slender, thumb-like distomedial protuberance; distomedial protuberance 0.4 × width of base of segment III; inner and outer margin with short, fine, simple setae; dorsally with a row of four medium, spine-like setae near outer margin. Segment III approximately semi-circular; 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. 39a, b ). Ratio of foreleg segments 1.3:1.0:0.6:0.2. Femur. Length ca. 3 × maximum width. Dorsal margin with a row of ca. 21 curved, spine-like setae and a few spine-like setae near margin; length of setae 0.25 × maximum width of femur. Apex rounded; with a few short, stout, pointed setae. Many short to long, lanceolate setae scattered along the ventral margin; femoral patch absent. Tibia. Dorsal margin with a row of short, stout setae. Ventral margin with a row of curved, spine-like setae, on apex one to several stout, spine-like setae and a tuft of long, fine, simple setae. Anterior surface scattered with stout, lanceolate setae. Patellotibial suture present on basal 1/2. Tarsus. Dorsal margin almost bare. Ventral margin with a row of curved spine-like setae. Tarsal claw with one row of ten denticles; distally pointed; with four stripes; subapical setae absent.

Tergum ( Fig. 39c ). Surface with irregular rows of U-shaped scale bases and scattered micropores. Posterior margin of tergum IV with triangular spines, approx. as long as wide.

Gills. Present on segments II–VII.

Paraproct ( Fig. 39d ). Distally not expanded, with ca. 15 stout marginal spines and some submarginal spines. Surface scattered with U-shaped scale bases and fine, simple setae. Cercotractor with numerous small marginal spines and some submarginal spines.

Etymology.

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

Distribution.

Indonesia: Seram.

Biological aspects.

The specimen was collected at an altitude of 2,000 m.

Type-material.

Holotype. Larva (on slide, GBIFCH 00592207), Indonesia, Maluku, Seram, Waihuhu below Mt. Binaya, 2,000 m, 10.IV.2012, 03°10.01'S, 129°28.93'E, M. Balke leg. (AMB11). Temporary deposited in MZL before definitely housed in MZB.

Figures

Figure 38. Labiobaetis seramensis 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 39. Labiobaetis seramensis sp. nov., larva morphology: a Foreleg b Fore claw c Tergum IV d Paraproct.

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.