Labiobaetis schwanderae, 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 : 59-64

17. Labiobaetis schwanderae sp. n. Figures 32, 33, 61b, 65a

Diagnosis.

Larva. Following combination of characters: A) labrum dorsal arc of setae composed of one plus five long, simple setae; B) maxillary palp 1.3 × as long as length of galea-lacinia; segment II apically rounded, with an excavation at inner lateral margin; C) labial palp segment II with a compact, rounded distomedial protuberance, segment III conical; D) fore femur rather broad, length 2.7 × maximum width, dorsal margin with a row of ca. 21 curved, spine-like setae and many stout, pointed setae near margin; E) fore claw with a row of 8 denticles; F) spines at posterior margin of tergum IV mostly rounded, about as long as wide; G) paraproct surface with U-shaped scale bases and scattered fine, slightly spatulate setae and micropores.

Description.

Larva (Figs 32, 33, 61b). Body length 5 mm; antenna: approximately twice as long as head length.

Colouration. Head, thorax and abdomen dorsally brown, head and thorax with bright median, dorsal suture. Head, thorax and abdomen ventrally colourless. Legs colourless with some brown spots, femur with brown dorsal margin, caudal filaments brown.

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. 32a). Rectangular, length 0.7 × 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 five long, simple setae. Ventrally with marginal row of setae composed of lateral and anterolateral long, feathered setae and medial long, bifid, pectinate setae; ventral surface with five short, spine-like setae near lateral and anterolateral margin.

Right mandible (Fig. 32b, 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. Tuft of setae at apex of mola present.

Left mandible (Fig. 32d, 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, with minute denticles towards subtriangular process. Subtriangular process long and slender, above level of area be tween 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. 32f). Lingua shorter than superlingua. Lingua longer than broad; medial tuft of stout setae present; distal half laterally expanded. Superlingua rounded; lateral margin rounded; fine, long, simple setae along distal margin.

Maxilla (Fig. 32g). 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 spine-like seta and six long, simple setae. Maxillary palp 1.3 × 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 excavation at inner distolateral margin.

Labium (Fig. 32h). Glossa basally broad, narrowing toward apex; shorter than paraglossa; inner margin with ten spine-like setae increasing in length distally; apex with two long and one short, robust, pectinate setae; outer margin with six long spine-like setae increasing in length distally; 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 two medium, simple setae; ventrally with four long, spine-like setae near inner margin. Labial palp with segment I 0.6 × length of segments II and III combined. Segment I covered with short and medium, fine, simple setae ventrally and with 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 row of three long, spine-like setae. Segment III conical; apex rounded; length 0.8 × width; ventrally covered with short and medium spine-like, simple setae and short, fine, simple setae.

Hind wing pads absent.

Foreleg (Fig. 33a, b). Ratio of foreleg segments 1.2:1.0:0.6:0.2. Femur. Length ca. 3 × maximum width. Dorsal margin with a row of ca. 21 curved, spine-like setae and with many stout, pointed setae near margin; length of setae 0.2 × maximum width of femur. Apex rounded; with one pair of curved, spine-like setae and many short, stout, pointed setae. Many stout, lanceolate setae and a few fine, simple setae scattered along ventral margin; femoral patch poorly developed. Tibia. Dorsal margin with a few curved, spine-like setae. Ventral margin with a row of curved, spine-like setae and some longer, spine-like, bipectinate setae and a tuft of long, fine, simple setae on apex. Anterior surface scattered with many stout, lanceolate setae. Tibio-patellar suture present on basal 1/2. Tarsus. Dorsal margin with a row of short, curved, spine-like setae and long, simple setae. Ventral margin with a row of curved, spine-like setae. Tarsal claw with one row of eight denticles; distally pointed; with five stripes; subapical setae absent.

Tergum (Fig. 33c). Surface with irregular rows of U-shaped scale bases and scattered fine, simple setae and micropores, scales egg-shaped. Posterior margin of tergum IV with rounded or triangular spines, about as long as wide.

Gills (Fig. 33d). 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 1/2 VI combined. Gill VII as long as length of segments VIII and 1/3 IX combined.

Paraproct (Fig. 33e). Distally slightly expanded, with many marginal, stout spines. Surface with U-shaped scale bases and scattered fine, slightly lanceolate setae and micropores. Postero-lateral extension (cercotractor) with small marginal spines.

Etymology.

Dedicated to Tanja Schwander (University of Lausanne, UNIL) for her constant support during a master project of one of the authors (TK) in her lab.

Distribution.

New Guinea.

Biological aspects.

The specimens were collected at an altitude of 1400 m a.s.l.

Type-material.

Holotype. Nymph (on slide, GBIFCH 00465197), Papua New Guinea, Gulf, Marawaka, 1400 m, 11 Nov 2006, 07°05.66'S, 145°44.47'E, Balke & Kinibel (PNG 90). Deposited in ZSM. Paratypes. 2 nymphs (1 on slide, GBIFCH 00465198, 5 in alcohol, GBIFCH 00515234, deposited in MZL; 3 in alcohol, GBIFCH 00515235, deposited in ZSM), same data as holotype.