Labiobaetis janae, Kaltenbach, Thomas & Gattolliat, Jean-Luc, 2018

Kaltenbach, Thomas & Gattolliat, Jean-Luc, 2018, The incredible diversity of Labiobaetis Novikova & Kluge in New Guinea revealed by integrative taxonomy (Ephemeroptera, Baetidae), ZooKeys 804, pp. 1-136 : 34-39

10. Labiobaetis janae sp. n. Figures 19, 20, 59d, 64b

Diagnosis.

Larva. Following combination of characters: A) labrum dorsal arc of setae with one plus 6-7 long, simple setae; B) both mandibles with outermost denticle blade-like; C) hypopharynx with slightly concave distal margin of superlingua; D) maxillary palp somewhat longer than length of galea-lacinia; E) fore femur rather broad, length 2.6 × maximum width, dorsal margin with a row of ca. 34 curved, spine-like setae and with some stout, pointed setae near margin; F) gills long, gill IV as long as length of segments V to VII combined, gill VII somewhat longer than length of segments VIII to X combined.

Description.

Larva (Figs 19, 20, 59d). Body length 8-9 mm.

Colouration. Head, thorax and abdomen dorsally grey-brown, abdominal segments VI, IX and X brighter, head and thorax with bright median, dorsal suture, forewing pads with bright striation. Head, thorax and abdomen ventrally light grey-brown, legs colourless with brown medial spot and dorsal margin on femur, caudal filaments light brown.

Antenna with scape and pedicel sub-cylindrical, without distolateral process at scape; flagellum with lanceolate spines on apex of each segment.

Labrum (Fig. 19a). Rectangular, length 0.7 × maximum width. Distal margin with medial emargination and small process. Dorsally with medium, fine, simple setae scattered over surface; submarginal arc of setae composed of one plus 6-7 long, simple setae. Ventrally with marginal row of setae composed of lateral and anterolateral long, feathered setae and medial long, pectinate setae, centrally bifid; ventral surface with eight short, spine-like setae near lateral and anterolateral margin.

Right mandible (Fig. 19b, c). Incisors fused. Outer and inner sets of denticles with 3 + 3 denticles plus one minute intermediate denticle, outermost denticle blade-like. Inner margin of innermost denticle with a row of thin setae. Prostheca robust, apically and distolaterally denticulate. Margin between prostheca and mola straight. Tuft of setae at apex of mola present.

Left mandible (Fig. 19d, e). Incisors fused. Outer and inner sets of denticles with 3 + 4 denticles, outermost denticle blade-like. Prostheca robust, apically with small denticles and comb-shape structure. Margin between prostheca and mola straight, with few minute setae, and with minute denticles toward 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. 19f). Lingua about as long as superlingua. Lingua about as broad as long; medial tuft of stout setae present; distal half not expanded. Superlingua slightly concave; lateral margin rounded; fine, long, simple setae along distal margin.

Maxilla (Fig. 19g). 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 seven long, simple setae. Maxillary palp slightly longer than length of galea-lacinia; two segmented. Palp segment II 2.2 × length of segment I. Setae on maxillary palp fine and simple, scattered over surface of segments I and II. Apex of last segment slightly pointed, without excavation at inner distolateral margin.

Labium (Fig. 19h). Glossa basally broad, narrowing toward apex; shorter than paraglossa; inner margin with 7-8 spine-like setae increasing in length distally; apex with three long, robust, pectinate setae; outer margin with five long, spine-like setae; ventral surface with few short, fine, simple setae. Paraglossa sub-rectangular, curved inward; apex rounded; with three rows of long, robust, apically pectinate setae; dorsally with three medium, simple setae; ventrally with three long, spine-like setae near inner margin. Labial palp with segment I 0.8 × length of segments II and III combined. Segment I covered with micropores dorsally. Segment II with a short, thumb-like distomedial protuberance; distomedial protuberance 0.4 × width of base of segment III; inner and outer margin both with short, fine, simple setae; dorsally with row of five long, spine-like, simple setae. Segment III oblong; apex slightly pointed; length 1.1 × width; ventrally covered with long and medium spine-like, simple setae and short, fine, simple setae.

Hind wing pads absent.

Foreleg (Fig. 20a, b). Ratio of foreleg segments 1.5:1.0:0.6:0.3. Femur. Length ca. 3 × maximum width. Dorsal margin with a row of ca. 34 curved, spine-like setae and some stout, pointed setae near margin; length of setae 0.15 × maximum width of femur. Apex rounded; with two pairs of curved, spine-like setae and many short, stout, pointed setae. Many stout, lanceolate setae and a few fine, simple setae along ventral margin; femoral patch absent. Tibia. Dorsal margin with few short, curved, spine-like setae and a pair of longer, curved, spine-like setae on apex. Ventral margin with a row of curved, spine-like setae and some longer, stout, pointed setae on apex. Anterior surface scattered with many stout, lanceolate setae. Tibio-patellar suture present on basal 2/3. Tarsus. Dorsal margin with some short, spine-like setae and fine simple setae. Ventral margin with a row of curved, spine-like setae. Tarsal claw with one row of 12 denticles; distally pointed; with three stripes; subapical setae absent.

Tergum (Fig. 20c). Surface with many micropores and scattered W-shaped scale bases, scales oblong. Posterior margin of tergum IV with rounded or triangular spines, wider than long.

Gills (Fig. 20d). Present on segments II - VII. Margin with small denticles and long, fine, simple setae. Tracheae extending from main trunk to inner margin and partly to outer margin. Gill IV as long as length of segments V, VI and VII combined. Gill VII somewhat longer than length of segments VIII and X combined.

Paraproct (Fig. 20e). Distally expanded, with many marginal, stout spines. Surface with W-shaped scale bases and many micropores. Postero-lateral extension (cercotractor) with small marginal spines.

Etymology.

Dedicated to Janice ( “Jan”) Peters (Florida A & M University), who pioneered the collection of mayflies in New Guinea.

Distribution.

New Guinea.

Biological aspects.

The specimens were collected at an altitude of 3200 m a.s.l.

Type-material.

Holotype. Nymph (on slide, GBIFCH 00465181), Indonesia, Papua, Lake Habemma, stream, 3200 m, 19 Oct 2011, 04°07.77'S, 138°40.77'E, Balke (PAP07). Temporary deposited in MZL before definitely housed in MZB. Paratypes. 30 nymphs (1 on slide, GBIFCH 00465182, 19 in alcohol, GBIFCH 00515252, GBIFCH 00508126, deposited in MZL; 11 in alcohol, GBIFCH 00515253, deposited in ZSM), same data as holotype.