Labiobaetis rutschmannae, 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 : 56-59

16. Labiobaetis rutschmannae sp. n. Figures 30, 31, 61a, 65a

Diagnosis.

Larva. Following combination of characters: A) labrum dorsal submarginal arc of setae composed of one plus nine long, simple setae; B) maxillary palp longer than length of galea-lacinia, apically rounded, without 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. 26 curved, spine-like setae and many stout, pointed setae near margin; E) paraproct distally expanded, surface with slightly spatulate setae.

Description.

Larva (Figs 30, 31, 61a). Body length 5.2 mm.

Colouration. Head, thorax and abdomen dorsally brown, head and thorax with bright median, dorsal suture. Head, thorax and abdomen ventrally light brown. Femur dorsal margin light brown, legs otherwise colourless, caudal filaments basally light brown, otherwise colourless.

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

Labrum (Fig. 30a). Rectangular, length 0.7 × maximum width. Distal margin with medial emargination and a small process. Dorsally with medium, fine, simple setae and a few slightly spatulate setae; submarginal arc of setae composed of one plus nine 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 nine short, spine-like setae near lateral and anterolateral margin.

Right mandible (Fig. 30b, c). Incisors fused. Outer and inner sets of denticles with 4 + 3 denticles plus one small intermediate denticle. Inner margin of innermost denticle with a row of thin setae. Prostheca robust, apically denticulate. Margin between prostheca and mola slightly convex, with minute denticles. Tuft of setae at apex of mola present.

Left mandible (Fig. 30d, 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 slightly convex, 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. 30f). Lingua shorter than superlingua. Lingua longer than broad; medial tuft of stout setae present; distal half not expanded. Superlingua rounded; lateral margin rounded; fine, long, simple setae along distal margin.

Maxilla (Fig. 30g). Galea-lacinia with three 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 1.2 × 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, without excavation at inner distolateral margin.

Labium (Fig. 30h, i). 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 setae; outer margin with five long, spine-like setae; ventral surface with short, simple setae. Paraglossa sub-rectangular, curved inward; apex rounded; with three rows of long, robust, apically pectinate setae; dorsally with seven simple setae; ventrally with three long, spine-like setae near inner margin. Labial palp with segment I 0.9 × length of segments II and III combined. Segment I covered with micropores dorsally and ventrally with fine, simple setae along margins. Segment II with a compact, rounded distomedial protuberance; distomedial protuberance 0.2 × width of base of segment III; inner and outer margin both with short, fine, simple setae; dorsally with row of three long, spine-like setae. Segment III conical; apex rounded; length 0.9 × width; ventrally covered with short, fine, simple setae.

Hind wing pads absent.

Foreleg (Fig. 31a, 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. 26 curved, spine-like setae and with many stout, pointed setae near margin; length of setae 0.16 × maximum width of femur. Apex rounded; with some spine-like setae and many short, stout, pointed or apically rounded 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 stout, lanceolate setae and very fine, simple setae. Ventral margin with a row of curved, spine-like setae, on apex one stout, spine-like seta and a tuft of long, fine, simple setae. Anterior surface scattered with stout, lanceolate setae. Tibio-patellar suture present on basal 1/2. 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 8-10 denticles; distally pointed; with four stripes; subapical setae absent.

Tergum (Fig. 31c). Surface with irregular rows of U-shaped scale bases and scattered fine, simple setae. Posterior margin of tergum IV with rounded or triangular spines, wider than long.

Gills (Fig. 31d). 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 1/2 IX combined.

Paraproct (Fig. 31e). Distally expanded, with many marginal, stout spines. Surface with U-shaped scale bases and scattered fine, slightly lanceolate setae, fine, simple setae and micropores. Postero-lateral extension (cercotractor) with small marginal spines.

Etymology.

Dedicated to Sereina Rutschmann (University of Vigo, Spain) for her long-lasting support of our group in genetics.

Distribution.

New Guinea.

Biological aspects.

The specimens were collected in altitudes of 1800 m– 2000 m a.s.l.

Type-material.

Holotype. Nymph (on slide, GBIFCH 00465195), Papua New Guinea, Western Highlands, Simbai, 1800-2000 m, 01 Mar 2007, 05°14.28'S, 144°28.74'E, Kinibel (PNG 138). Deposited in ZSM. Paratype. Nymph (on slide, GBIFCH 00465196, deposited in MZL), Papua New Guinea, Western Highlands, Simbai, 2000 m, 28 Feb 2007, 05°15.17'S, 144°32.81'E, Kinibel (PNG 136).