Labiobaetis wilhelmensis, 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 : 76-80

22. Labiobaetis wilhelmensis sp. n. Figures 41, 42, 62b, 65b

Diagnosis.

Larva. Following combination of characters: A) labrum dorsal submarginal arc of setae composed of one plus 7-10 long, simple setae; B) maxillary palp somewhat longer than length of galea-lacinia, segment II apically slightly pointed and without excavation at inner lateral margin; C) labial palp segment III oblong, apically slightly pointed; D) labium paraglossa apically with five rows of long, robust, apically pectinate setae; E) fore femur rather broad, length ca. 3 × maximum width, dorsal margin with a row of ca. 29 curved, spine-like setae and many stout, pointed setae near margin; F) fore claw with one row of 13-15 denticles; G) tracheae of gills restricted to main trunk.

Description.

Larva (Figs 41, 42, 62b). Body length 6 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 light brown, legs colourless with light brown pattern as in Fig. 62b, caudal filaments light brown.

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

Labrum (Fig. 41a). Rectangular, length 0.8 × 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 7-10 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 nine short, spine-like setae near lateral and anterolateral margin.

Right mandible (Fig. 41b, c). Incisors fused. Outer and inner sets of denticles with 4 + 4 (sometimes three) denticles. Inner margin of innermost denticle 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. 41d, e). Incisors fused. Outer and inner sets of denticles with 3 + 3 denticles and one minute intermediate denticle. Prostheca robust, apically with small denticles and comb-shape structure. Margin between prostheca and mola straight. Subtriangular process long and slender, at the same level as 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. 41f). Lingua shorter than superlingua. Lingua broader than long; medial tuft of stout setae present; distal half laterally expanded. Superlingua rounded; lateral margin rounded; fine, long, simple setae along distal margin.

Maxilla (Fig. 41g). 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 7-8 long, simple setae. Maxillary palp slightly longer than length of galea-lacinia; two segmented. Palp segment II 1.3 × 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. 41h). Glossa basally broad, narrowing toward apex; shorter than paraglossa; inner margin with eleven spine-like setae; apex with three long, robust, pectinate setae; outer margin with 7-8 long, spine-like setae; ventral surface with short, fine, simple, scattered setae. Paraglossa sub-rectangular, curved inward; apex rounded; with five rows of long, robust, apically pectinate setae; dorsally with row of four medium, simple setae; ventrally with five 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 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 three long, spine-like setae. Segment III oblong; apex rounded; length 1.4 × width; ventrally covered with short and medium spine-like, simple setae and short, fine, simple setae.

Hind wing pads absent.

Foreleg (Fig. 42a, b). Ratio of foreleg segments 1.5:1.0:0.6:0.3. Fore femur. Length 2.6 × maximum width. Dorsal margin with a row of ca. 29 curved, spine-like setae and with many stout, pointed setae near margin; length of setae 0.14 × 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 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 and some longer, stout, pointed 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 2/3. Tarsus. Dorsal margin with a row of short, curved, spine-like setae. Ventral margin with a row of curved, spine-like setae and some stout, pointed setae near margin. Tarsal claw with one row of 13-15 denticles; distally pointed; with five stripes; subapical setae absent.

Tergum (Fig. 42c). Surface with irregular rows of U-shaped scale bases and scattered fine, simple setae, micropores and egg-shaped scales. Posterior margin of tergum IV with rounded or triangular spines, about as long as wide.

Gills (Fig. 42d). Present on segments II–VII. Margin with small denticles intercalating long, fine, simple setae. Tracheae restricted to main trunk. 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. 42e). Distally not expanded, with ca. 26 marginal, stout spines. Surface with U-shaped scale bases and scattered fine, simple setae. Postero-lateral extension (cercotractor) with small marginal spines.

Etymology.

Refers to the type locality at Mt. Wilhelm.

Distribution.

New Guinea.

Biological aspects.

The specimens were collected in altitudes of 2900 m a.s.l. and 3210 m a.s.l.

Type-material.

Holotype. Nymph (on slide, GBIFCH 00465209), Papua New Guinea, Simbu Prov., 05°48.050'S, 145°04.15'E, (GPS)', Mt. Wilhelm, Pindaunde Creek, 3210 m a.s.l., (10895 ft GPS), S32 (oria.3), 17 Aug 1999, L. Čížek leg. Deposited in MZL. Paratypes. 14 nymphs (10 in alcohol, GBIFCH 00515247, deposited in MZL; 4 in alcohol, GBIFCH 00515248, deposited in ZSM), same data as holotype; 108 nymphs (3 on slides, GBIFCH 00465210, GBIFCH 00465211, GBIFCH 00465212, 61 in alcohol, GBIFCH 00515249, GBIFCH 00508127, deposited in MZL; 44 in alcohol, GBIFCH 00515250, deposited in ZSM), Papua New Guinea, Simbu Prov., 05°49' 145°04.5', Mt. Wilhelm, Pindaunde Creek, 2900 m a.s.l., (in forest), S3 (oria.4), 18 Aug 1999, leg. L. Čížek.