Labiobaetis planus, 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 : 48-51

14. Labiobaetis planus sp. n. Figures 26, 27, 60c, 65a

Diagnosis.

Larva. Following combination of characters: A) labrum dorsal submarginal arc of setae composed of one plus 5-7 long, simple setae; B) maxillary palp much longer than length of galea-lacinia, apically rounded, with very poorly developed excavation at inner distolateral margin; C) labial palp segment II with a compact, rounded distomedial protuberance; D) fore femur rather broad, length ca. 3 × maximum width, dorsal margin with a row of ca. 19 curved, spine-like setae and some stout, pointed setae near margin; E) fore claw with 7 - 8 denticles; F) paraproct distally expanded, surface with few slightly spatulate setae.

Description.

Larva (Figs 26, 27, 60c). Body length 3.3 mm; antenna: approximately twice as long as head length.

Colouration. Head, thorax and abdomen dorsally brown, head and thorax with bright median, dorsal suture, forewing pads with bright striation. Head, thorax and abdomen ventrally light brown. Legs colourless, femur with large, distomedial, brown spot and brown dorsal margin, caudal filaments light brown.

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

Labrum (Fig. 26a). Rectangular, length 0.7 × maximum width. Distal margin with medial emargination and a small process. Dorsally with many medium to long, fine, simple setae; submarginal arc of setae composed of one plus 5-7 long, simple setae. Ventrally with marginal row of setae composed of lateral and anterolateral long, feathered setae and medial long, bifid setae; ventral surface with two short, spine-like setae near lateral margin.

Right mandible (Fig. 26b, c). Incisors fused. Outer and inner sets of denticles with 4 + 3 denticles plus one small intermediate denticle. Inner margin of innermost den ticle with a row of thin setae. Prostheca robust, apically denticulate. Margin between prostheca and mola straight. Tuft of setae at apex of mola present.

Left mandible (Fig. 26d, e). Incisors fused. Outer and inner sets of denticles with 4 + 4 denticles. Prostheca robust, apically with small denticles and comb-shape 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 present.

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

Hypopharynx (Fig. 26f). Lingua about as long as superlingua. Lingua about as broad as long; medial tuft of stout setae present; distal half not expanded. Superlingua rounded; lateral margin rounded; fine, long, simple setae along distal margin.

Maxilla (Fig. 26g). Galea lacinia with four 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 1.6 × as long as length of galea-lacinia; two segmented. Palp segment II 1.2 × length of segment I. Setae on maxillary palp fine and simple, scattered over surface of segments I and II. Apex of last segment rounded, with very slight excavation at inner distolateral margin.

Labium (Fig. 26h). Glossa basally broad, narrowing toward apex; shorter than paraglossa; inner margin with 7-8 spine-like setae increasing in length distally; apex with two long and one medium, robust, pectinate setae; outer margin with five long, spine-like setae; ventral surface with short, fine, simple, scattered setae. Paraglossa sub-rectangular, curved inward; apex rounded; with three rows of long, robust, apically pectinate setae; dorsally with 2-3 medium, simple setae; ventrally with 3-4 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 short, fine, simple setae ventrally and micropores dorsally. Segment II with a compact, rounded distomedial protuberance; distomedial protuberance 0.4 × width of base of segment III; inner and outer margin both with short, fine, simple setae; dorsally with a row of 3-4 long, spine-like, simple setae. Segment III conical; apex truncate; length 0.9 × width; ventrally covered with short and medium spine-like, simple setae and short, fine, simple setae.

Hind wing pads absent.

Foreleg (Fig. 27a, 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 ca. 19 curved, spine-like setae and with some stout, pointed setae near margin; length of setae 0.2 × maximum width of femur. Apex rounded; with one pair of spine-like setae and some short, stout, pointed setae. Many stout, lanceolate setae and a few fine, simple setae along ventral margin; femoral patch poorly developed. Tibia. Dorsal margin with a row of short, curved, spine-like setae and a row of long, fine, simple setae and a row of stout, lanceolate setae near margin. Ventral margin with a row of curved, spine-like setae, on apex one bipectinate, spine-like seta and a tuft of long, fine, simple setae. Anterior surface scattered with stout, lanceolate setae. Tibio-patellar suture present on basal 1/3. Tarsus. Dorsal margin with a row of short, spine-like setae and long, simple setae. Ventral margin with a row of curved, spine-like setae. Tarsal claw with one row of 7-8 denticles; distally pointed; with four stripes; subapical setae absent.

Tergum (Fig. 27c). Surface with irregular rows of U-shaped scale bases and scattered micropores, scales short, apically rounded. Posterior margin of tergum IV with rounded spines, wider than long.

Gills (Fig. 27d). Present on segments II–VII. Margin with small denticles intercalating long, fine, simple setae. Tracheae extending from main trunk to inner and outer margins. Gill IV as long as length of segments V and VI combined. Gill VII as long as length of segments VIII and IX combined.

Paraproct (Fig. 27e). Distally expanded, with many marginal, stout spines. Surface with U-shaped scale bases and scattered fine, slightly lanceolate setae. Postero-lateral extension (cercotractor) with small, marginal spines.

Etymology.

Refers to the low altitude (95 m a.s.l.) of the type locality.

Distribution.

New Guinea.

Biological aspects.

The specimens were collected at an altitude of 95 m a.s.l.

Type-material.

Holotype. Nymph (on slide, GBIFCH 00465191), Indonesia, Papua, Sorong, inland, 95 m, 19 Feb 2006, 00°49.35'S, 131°24.20'E, Balke & Tindige (BH 20). Temporary deposited in MZL before definitly housed in MZB. Paratypes. 16 nymphs (2 on slides, GBIFCH 00465192, GBIFCH 00465193, 9 in alcohol, GBIFCH 00515269, GBIFCH 00508149, GBIFCH 00508150, deposited in MZL; 5 in alcohol, GBIFCH 00515270, deposited in ZSM), same data as holotype.