Labiobaetis altus, 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 : 64-68

19. Labiobaetis altus sp. n. Figures 35, 36, 61c, 65b

Diagnosis.

Larva. Following combination of characters: A) labrum dorsal submarginal arc of setae composed of one plus 5-6 long, simple setae; B) maxillary palp somewhat longer as length of galea-lacinia, apically constricted, without excavation at inner distolateral margin; C) labium paraglossa apically with four rows of long, robust, apically pectinate setae; D) labial palp segment II with a short, thumb-like distomedial protuberance; E) fore femur rather broad, length ca. 3 × maximum width, dorsal margin with a row of ca. 30 curved, spine-like setae and many stout, pointed setae near margin; F) fore claw with one row of 12-13 denticles.

Description.

Larva (Figs 35, 36, 61c). Body length 9.2 mm.

Colouration. Head, thorax and abdomen dorsally brown, head and thorax with bright median, dorsal suture, thorax and abdomen with bright pattern as in Fig. 61c, forewing pads with bright striation. Head, thorax and abdomen ventrally colourless, femur with distomedial brown spot, legs otherwise colourless.

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. 35a). 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 5-6 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 9-11 short, spine-like setae near lateral and anterolateral margin.

Right mandible (Fig. 35b, c). Incisors fused. Outer and inner sets of denticles with 3 + 4 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. 35d, 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, with minute denticles towards 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. 35f). Lingua longer than superlingua. Lingua longer than broad; medial tuft of stout setae present; distal half laterally expanded. Superlingua straight; lateral margin rounded; fine, long, simple setae along distal margin.

Maxilla (Fig. 35g). 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 1.2 × length of segment I. Setae on maxillary palp fine and simple, scattered over surface of segments I and II. Apex of last segment constricted, without excavation at inner distolateral margin.

Labium (Fig. 35h, i). Glossa basally broad, narrowing toward apex; shorter than paraglossa; inner margin with 10-11 spine-like setae increasing in length distally; apex with three long, robust setae; outer margin with 6-8 spine-like setae; ventral surface with short, fine, simple, scattered setae. Paraglossa sub-rectangular, curved inward; apex rounded; with four rows of long, apically pectinate setae; dorsally with three medium, simple setae; ventrally with five 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 short, fine, simple setae ventrally and micropores dorsally. Segment II with a short, thumb-like distomedial protuberance; distomedial protuberance 0.5 × width of base of segment III; inner margin with short, fine, simple setae, more numerous at apex; outer margin with short, fine, simple setae; dorsally with row of 3-4 long, spine-like, simple setae. Segment III oblong; apex slightly pointed; length 1.2 × width; ventrally covered with short and medium spine-like, simple setae and short, fine, simple setae.

Hind wing pads absent.

Foreleg (Fig. 36a, b). Ratio of foreleg segments 1.6:1.0:0.8:0.3. Femur. Length ca. 3 × maximum width. Dorsal margin with a row of ca. 30 curved, spine-like setae on margin, and with many stout, pointed setae near margin; length of setae 0.13 × maximum width of femur. Apex rounded; with one pair of curved, spine-like setae and some 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 row of curved, spine-like setae and long, 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 and long, simple setae. Ventral margin with a row of curved, spine-like setae. Tarsal claw with one row of 12-13 denticles; distally pointed; with 3-4 stripes; subapical setae absent.

Tergum (Fig. 36c). Surface with irregular rows of U-shaped scale bases and scattered fine, simple setae and micropores, scales slightly triangular. Posterior margin of tergum IV with rounded or triangular spines, about as long as wide.

Gills (Fig. 36d). 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. 36e). Distally not expanded, with ca. 20 marginal, stout spines. Surface with U-shaped scale bases and scattered fine, simple setae. Postero-lateral extension (cercotractor) with small marginal spines.

Etymology.

Latin word for high, refers to the altitude of the type locality (2700 m a.s.l.).

Distribution.

New Guinea.

Biological aspects.

The specimens were collected in altitudes of 2700 m a.s.l. and 2900 m a.s.l.

Type-material.

Holotype. Nymph (on slide, GBIFCH 00465199), Papua New Guinea, Enga, Kumul Lodge at foot of Mt. Hagen, 2700 m, 05 Dec 2006, 05°47.55'S, 143°58.76'E, Balke & Kinibel (PNG 124). Deposited in ZSM. Paratypes. 4 nymphs (1 on slide, GBIFCH 00465200, 3 in alcohol, GBIFCH 00515273, GBIFCH 00508131, deposited in MZL), same data as holotype; 1 nymph (on slide, GBIFCH 00465201, deposited in MZL), Papua New Guinea, Simbu Prov., 05°49'S, 145°04.50'E, Mt. Wilhelm, Pindaunde Creek, 2900 m a.s.l. (in forest), S3 (oria.4), 18 Aug 1999, leg. L. Čížek.