Labiobaetis onim, 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 onim sp. nov.

Type material.

Holotype. Indonesia • larva; Papua Barat, River Je, Loc. Arfak, East of Amber village; 01°10'59"S, 133°56'51"E; 1200 m; 16.vi.2016, leg. Sumoked; on slide; GBIFCH00763713; MZB. Paratypes. Indonesia • 2 larvae; same data as holotype; 2 on slides; GBIFCH00515649, GBIFCH00592706; MZB, MZL.

Diagnosis.

Larva. Following combination of characters: A) dorsal surface of labrum with submarginal arc of one plus two long, simple setae (Fig. 15a); B) labial palp segment II with short thumb-like (atypical for the group), distomedial protuberance, segment III broad, rounded (Fig. 15h); C) fore femur rather broad, length ca. 3 × maximum width, dorsal margin with more than 70 long, curved spine-like setae plus some additional spine-like setae near margin (Fig. 16a); D) hind protoptera absent; E) six pairs of gills (gill I absent); F) paraproct distally not expanded, with 8-12 stout, marginal spines (Fig. 16g).

Description.

Larva (Figs 15, 16, 20c, d). Body length 5.6-5.9 mm. Cerci ca. 1/2 of body length, paracercus ca. 2/3 of cerci length. Antenna: approx. twice as long as head length.

Colouration (Fig. 20c, d). Head dorsally light brown, thorax and abdomen dorsally dark brown, with light brown pattern on thorax as in Fig. 20c, abdominal segment I light brown and abdominal segments V-VII orange. Head, thorax, and abdomen ventrally light brown, with pattern as in fig. 20d, abdominal segments V-VII light orange and abdominal segments VIII-X dark brown. Legs ecru, caudalii ecru.

Antenna (Fig. 16h) with scape and pedicel sub cylindrical, without distolateral process at scape.

Labrum (Fig. 15a). Sub-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 one plus two long, simple setae; large distance between both arc setae. Ventrally with marginal row of setae composed of anterolateral long, feathered setae and medial long, bifid, pectinate setae; ventral surface with ca. five short, spine-like setae near lateral and anterolateral margin.

Right mandible (Fig. 15b, c). Incisor and kinetodontium fused. Incisor with six 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. Tuft of setae at apex of mola present.

Left mandible (Fig. 15d, e). 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. 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 and superlinguae (Fig. 15f). Lingua shorter than superlingua. Lingua longer than broad; distal half laterally slightly expanded; medial tuft of stout setae well developed and long. Superlinguae distally rounded; lateral margins rounded; fine, long, simple setae along distal margin.

Maxilla (Fig. 15g). 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 three long, simple setae. Maxillary palp ca. 1.3 × length of galea-lacinia; 2-segmented; palp segment II 1.1 × length of segment I; setae on maxillary palp fine, simple, scattered over surface of segments I and II; apex of last segment without excavation at inner distolateral margin, apically rounded.

Labium (Fig. 15h). Glossa basally broad, narrowing toward apex; shorter than paraglossa; inner margin with one long, spine-like seta; apex with two long and one medium robust, pectinate setae; outer margin with five or six spine-like setae; ventral surface with fine, simple, scattered setae. Paraglossa sub-rectangular, curved inward; apex rounded; with three rows of long, robust, distally pectinate setae in apical area, sometimes one short, simple seta in anteromedial area, and one short, simple seta in posteromedial area; dorsally with a row of three long, spine-like setae near inner margin. Labial palp with segment I approx. as long as segments II and III combined. Segment I ventrally with short, fine, simple setae. Segment II with short thumb-like, distomedial protuberance; distomedial protuberance 0.3 × width of base of segment III; ventral surface with short, simple setae; dorsally with one spine-like seta near outer margin. Segment III broad, rounded; length 0.7 × width; ventrally covered with short, spine-like, simple setae and short, fine, simple setae.

Hind protoptera absent.

Foreleg (Fig. 16a, b). Ratio of foreleg segments 1.2:1.0:0.5:0.2. Femur. Length ca. 3 × maximum width. Dorsal margin with a dense row of more than 70 long, curved, spine-like setae and distally some additional long, spine-like setae near margin; length of setae 0.40 × maximum width of femur. Apex rounded, with some short, stout setae. Many stout, lanceolate setae scattered along ventral margin; femoral patch absent. Tibia. Dorsal margin with a dense row of long, spine-like setae. Ventral margin with a row of short, curved, spine-like setae. Anterior surface scattered with short, stout, lanceolate setae. Patellotibial suture present on basal 1/2 area. Tarsus. Dorsal margin with a row of short, spine-like setae. Ventral margin with a row of short, curved, spine-like setae, distalmost seta much longer. Claw with one row of ten or eleven denticles; distally pointed; with two or three stripes; subapical setae absent.

Middle and hind legs (Fig. 16c, d). As foreleg, but with reduced femoral patch.

Terga (Fig. 16e). Surface with scattered scales and micropores. Posterior margin of tergum IV with discontinuous row of triangular spines, spines wider than long. Triangular spines present on segments IV-VII, absent on segments I-III.

Gills (Fig. 16f). Present on segments II-VII. Margin with small denticles intercalating fine simple setae. Tracheae partly 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 slightly longer than length of segment VIII.

Paraproct (Fig. 16g). Distally not expanded, with 8-12 stout, marginal spines, partly with split tips. Surface scattered with scales and micropores. Cercotractor with numerous small, marginal spines, partly with split tips.

Etymology.

Dedicated to the indigenous Onim people of Papua Barat, where the type locality is located.

Distribution.

Indonesia: Papua Barat (Fig. 21c).

Biological aspects.

The specimens were collected at an altitude of 1200 m, together with L. arfak sp. nov.