Labiobaetis arfak, 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 arfak 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; GBIFCH00592770; MZB. Paratypes. Indonesia • 27 larvae; same data as holotype; 4 on slides; GenBank MW868312, MW868313; GBIFCH00763714, GBIFCH00763715, GBIFCH00592767, GBIFCH00829897; MZL; 23 in alcohol; GBIFCH00515626, GBIFCH00515648; MZB, MZL.

Diagnosis.

Larva. Following combination of characters: A) dorsal surface of labrum with submarginal arc of one plus two long, simple setae (Fig. 13a); B) labial palp segment II with narrow thumb-like, distomedial protuberance, segment III broad, rounded (Fig. 13h); C) fore femur rather broad, length 2.7 × maximum width, dorsal margin with 17-20 spine-like setae plus a second row of spine-like setae near margin (Fig. 14a); D) hind protoptera absent; E) six pairs of gills (gill I absent); F) tergites VIII and IX posterolaterally with two long spines (Fig. 14f); G) paraproct distally not expanded, with ca. eight stout, marginal spines (Fig. 14h).

Description.

Larva (Figs 13, 14, 20a, b). Body length 3.3-4.4 mm. Cerci ca. 2/3 of body length, paracercus ca. 2/3 of cerci length. Antenna: approx. 2.5 × as long as head length.

Colouration (Fig. 20a, b). Head, thorax and abdomen dorsally dark brown, abdominal tergites V and VI yellow brown (Fig. 20a). Thorax ventrally ecru, abdomen ventrally brown, with pattern as in Fig. 20b. Legs light brown; femur dorsally and ventrally dark brown, basally and distomedially with dark brown areas (Fig. 20b). Caudalii light brown, basally brown.

Antenna (Fig. 14i) with scape and pedicel sub cylindrical, without distolateral process at scape.

Labrum (Fig. 13a). 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. Ventrally with marginal row of setae composed of anterolateral long, feathered setae and medial long, bifid, pectinate setae; ventral surface with ca. three short, spine-like setae near lateral and anterolateral margin.

Right mandible (Fig. 13b, c). 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 convex, with minute denticles. Tuft of setae at apex of mola present.

Left mandible (Fig. 13d, 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 almost straight, with few 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 almost straight. Basal half with fine, simple setae scattered over dorsal surface.

Hypopharynx and superlinguae (Fig. 13f). 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. 13g). 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 spine-like seta and four long, simple setae. Maxillary palp ca. 1.3 × length of galea-lacinia; 2-segmented; palp segment II 1.5 × length of segment I; setae on maxillary palp fine, simple, scattered over surface of segment II; apex of last segment without excavation at inner distolateral margin, apically rounded.

Labium (Fig. 13h). Glossa basally broad, narrowing toward apex; shorter than paraglossa; inner margin with 3-5 spine-like setae, distalmost seta much longer; apex with two long and one medium robust, pectinate setae; outer margin with three or four 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, one or two short, simple setae in anteromedial area and one short, simple seta in posterolateral area; dorsally with a row of four long, spine-like setae near inner margin. Labial palp with segment I 0.9 × length of segments II and III combined. Segment I ventrally with short, fine, simple setae. Segment II with narrow thumb-like, distomedial protuberance; distomedial protuberance 0.4 × width of base of segment III; ventral surface with short, simple setae; dorsally with two or three spine-like setae near outer margin. Segment III broad, rounded; length 0.9 × width; ventrally covered with short, spine-like, simple setae and short, fine, simple setae.

Hind protoptera (Fig. 14j) absent.

Foreleg (Fig. 14a, b). Ratio of foreleg segments 1.3:1.0:0.5:0.2. Femur. Length 2.7 × maximum width. Dorsal margin with a row of 17-20 curved, spine-like setae and a second row of spine-like setae near margin; length of setae 0.25 × maximum width of femur. Apex rounded, with one or two pairs of spine-like setae and some short, stout setae. Many stout, lanceolate setae scattered along ventral margin; femoral patch absent. Tibia. Dorsal margin with a row of short, spine-like setae and fine, simple setae. Ventral margin with a row of short, curved, spine-like setae. Anterior surface scattered with few 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 curved, spine-like setae. Claw with one row of 9-11 denticles; distally pointed; with ca. five stripes; subapical setae absent.

Middle and hind legs (Fig. 14c, d). As foreleg, but with reduced femoral patch.

Terga (Fig. 14e, f). Surface with irregular rows of U-shaped scale bases and scattered micropores. Posterior margin of tergum IV with triangular spines, wider than long. Posterolateral margins of terga VIII and IX with two long, pointed spines.

Gills (Fig. 14g). 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 2/3 VI combined. Gill VII as long as length of segments VIII and 2/3 IX combined.

Paraproct (Fig. 14h). Distally not expanded, with ca. eight stout, marginal spines. Surface scattered with U-shaped scale bases, micropores and fine, simple setae. Cercotractor with numerous small, marginal spines.

Etymology.

Dedicated to the indigenous Arfak 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. onim sp. nov.