Labiobaetis catadupa, Kaltenbach & Gattolliat, 2021

Kaltenbach, Thomas & Gattolliat, Jean-Luc, 2021, New species of Labiobaetis Novikova & Kluge from Southeast Asia and New Guinea (Ephemeroptera, Baetidae), ZooKeys 1067, pp. 159-208 : 159

Labiobaetis catadupa sp. nov.

Type material.

Holotype. Brunei • larva; Temburong District, Ulu Temburong National Park, Belalong River (near field station); 04°32'49"N, 115°09'30"E; 100 m; v. 2014; leg. K. Baker; on slide; GBIFCH00592448; MZL. Paratypes. Brunei • 17 larvae; Temburong District, Ulu Temburong National Park; 04°33'10"N, 115°09'20"E; v. 2014; leg. K. Baker; 2 on slides; GenBank MW868314; GBIFCH00592439, GBIFCH00592440; 15 in alcohol; GBIFCH00515571, GBIFCH00515573, GBIFCH00515598; MZL • 12 larvae; Temburong District, Ulu Temburong National Park; 04°32'42"N, 115°09'31"E; v. 2014; leg. K. Baker; 1 on slide; GBIFCH00592442; 11 in alcohol; GBIFCH00515597; MZL • 4 larvae; Temburong District, Ulu Temburong National Park; 04°32'23"N, 115°09'34"E; 25.-31.vii. 2016; leg. K. Baker; in alcohol; GBIFCH00515576; MZL • 9 larvae; Temburong District, Ulu Temburong National Park, Mata Ikan; 04°32'51"N, 115°09'25"E; 25.-31.vii. 2016; leg. K. Baker; 1 on slide; GBIFCH00592441; 8 in alcohol; GBIFCH00515582, GBIFCH00515583, GBIFCH00515589, GBIFCH00515590; MZL • 12 larvae; Temburong District, Ulu Temburong National Park; 04°33'39"N, 115°08'54"E; 25.-31.vii. 2016; leg. K. Baker; in alcohol; GBIFCH00515574, GBIFCH515575, GBIFCH515578; MZL • 5 larvae; Temburong District, Ulu Temburong National Park; 04°33'39"N, 115°08'51"E; 25.-31.vii. 2016; leg. K. Baker; 1 on slide; GBIFCH00515577; 4 in alcohol; GBIFCH00515599, GBIFCH00515572, GBIFCH00515621, GBIFCH00515600; MZL • 6 larvae; Temburong District, Ulu Temburong National Park; 04°33'10"N, 115°09'20"E; 25.-31.vii. 2016; leg. K. Baker; in alcohol; GBIFCH00515588, GBIFCH00515593; MZL. Other material. Brunei • 25 larvae; Temburong District, Ulu Temburong National Park; 04°32'42"N, 115°09'31"E; 25.-31.vii. 2016; leg. K. Baker; in alcohol; GBIFCH00515584, GBIFCH00515579, GBIFCH00515587, GBIFCH00515592; MZL • 5 larvae; Temburong District, Ulu Temburong National Park; 04°32'56"N, 115°09'27"E; 25.-31.vii. 2016; leg. K. Baker; in alcohol; GBIFCH00515580, GBIFCH00515586, GBIFCH00515591; MZL.

Diagnosis.

Larva. Following combination of characters: A) dorsal surface of labrum with submarginal arc of 17-19 long, feathered setae with broad middle part (Figs 1a, b, 3); B) labial palp segment II with extended thumb-like distomedial protuberance, segment III slightly pentagonal; glossae much shorter than paraglossae (Fig. 1i); C) left mandible without setae at apex of mola; D) fore femur length ca. 3 × maximum width, dorsal margin with 17-19 curved, spine-like setae (Fig. 2a); E) claw with long subapical seta on posterior side and reduced subapical seta on anterior side (Figs 2b, 4a); F) hind protoptera absent; G) six pairs of gills (gill I absent); H) paraproct distally expanded, with ca. 40 stout, marginal spines.

Description.

Larva (Figs 1-3, 4a, 17a). Body length 2.6-6.0 mm. Cerci: ca. 2/3 of body length. Paracercus: ca. 1/5 of cerci length. Antenna: approx. twice as long as head length.

Colouration (Fig. 17a). Head, thorax and abdomen dorsally and ventrally brown. Legs light brown, caudalii light brown.

Antenna (Fig. 2f) with scape and pedicel sub cylindrical, without distolateral process at scape.

Labrum (Fig. 1a, b). Rectangular, length 0.6 × 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 17-19 long, feathered setae with broad middle part. Ventrally with marginal row of setae composed of anterolateral long, feathered setae and medial long, bifid setae; ventral surface with ca. two short, spine-like setae near lateral and anterolateral margin.

Right mandible (Fig. 1c, d). Incisor and kinetodontium fused. Incisor with five denticles; kinetodontium with three denticles, inner margin of innermost denticle with a row of thin setae. Prostheca robust, apically denticulate. Margin between prostheca and mola slightly convex, with few minute denticles. Tuft of setae at apex of mola present.

Left mandible (Fig. 1e, f). Incisor and kinetodontium fused. Incisor with five denticles; kinetodontium with three denticles. Prostheca robust, apically with small denticles and comb-shaped structure. Margin between prostheca and mola straight, with minute denticles. 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 slightly convex. Basal half with fine, simple setae scattered over dorsal surface.

Hypopharynx and superlinguae (Fig. 1g). Lingua shorter than superlingua. Lingua approx. as long as broad; distal half laterally not expanded; medial tuft of stout setae well developed. Superlinguae distally rounded; lateral margins rounded; fine, long, simple setae along distal margin.

Maxilla (Fig. 1h). Galea-lacinia ventrally with two simple, apical setae under canines. 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 pectinate, spine-like seta and two or three medium, simple setae. Maxillary palp ca. 1.2 × length of galea-lacinia; 2-segmented; palp segment II approx. as long as segment I; setae on maxillary palp fine, simple, scattered over surface of segments I and II; apex of last segment with slight excavation at inner distolateral margin.

Labium (Fig. 1i). Glossa basally broad, narrowing toward apex; much shorter than paraglossa; inner margin with one spine-like seta; apex with two long and one medium, robust setae; outer margin with three spine-like setae; ventral surface with fine, simple, scattered setae. Paraglossa sub-rectangular, slightly curved inward; apex slightly concave; with three rows of long, robust, distally pectinate setae in apical area and two or three short, simple setae in anteromedial area; dorsally with two long, spine-like setae near inner margin. Labial palp with segment I 0.7 × length of segments II and III combined. Segment I ventrally with short, fine, simple setae. Segment II with extended thumb-like, distomedial protuberance, bent upwards; distomedial protuberance 0.8 × width of base of segment III; ventral surface with short, fine, simple setae; dorsally without spine-like setae near outer margin. Segment III slightly pentagonal; length 1.3 × width; ventrally covered with short, spine-like, simple setae and short, fine, simple setae.

Hind protoptera (Fig. 2g) absent.

Foreleg (Fig. 2a, b). Ratio of foreleg segments 1.2:1.0:0.5:0.2. Femur. Length ca. 3 × maximum width. Dorsal margin with a row of 17-19 curved, spine-like setae and a row of long, fine, simple setae; length of setae 0.24 × maximum width of femur. Apex rounded, with a pair of spine-like setae and some short, stout setae. Stout, apically rounded setae scattered along ventral margin; femoral patch absent. Tibia. Dorsal margin with a row of short, spine-like setae and long, fine, simple setae. Ventral margin with a row of short, curved, spine-like setae, on apex a tuft of fine, simple setae. Patellotibial suture present on basal 1/2. Tarsus. Dorsal margin with a row of fine, simple setae. Ventral margin with a row of curved, spine-like setae. Claw with one row of eight or nine denticles; distally pointed; with ca. four stripes; with long, subapical seta on posterior side and reduced, subapical seta on anterior side.

Terga (Fig. 2c). Surface with irregular rows of U-shaped scale bases and scattered fine, simple setae. Posterior margin of tergum IV with rounded spines, wider than long.

Gills (Fig. 2d). 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 1/3 VI combined. Gill VII as long as length of segment VIII.

Paraproct (Fig. 2e). Distally expanded, with ca. 40 stout, marginal spines. Surface scattered with fine, simple setae. Cercotractor with numerous small, marginal spines.

Etymology.

Based on the Latin word Labiobaetis catadupa , meaning waterfall, with reference to the habitat of the species.

Distribution.

Brunei (Fig. 21b).

Biological aspects.

The specimens were collected at an altitude of 150 m, mostly from waterfalls with slope angles of 16° to 50° and lengths between 5 m and 20 m (Fig. 5; Baker et al. 2017a, b). They were sampled on rock in fast flowing water and others it was a film of water with algae/moss (pers. comm. Kate Baker, University Exeter, Great Britain).