Labiobaetis dalisay, Kaltenbach & Garces & Gattolliat, 2020

Kaltenbach, Thomas, Garces, Jhoana M. & Gattolliat, Jean-Luc, 2020, The success story of Labiobaetis Novikova & Kluge in the Philippines (Ephemeroptera, Baetidae), with description of 18 new species, ZooKeys 1002, pp. 1-114 : 1

Labiobaetis dalisay sp. nov. Figures 3 , 4 , 41a , 48b

Diagnosis.

Larva. Following combination of characters: A) dorsal surface of labrum with 6-8 long, dendritic setae; B) labial palp segment II with a slender thumb-like distomedial protuberance, segment III subrectangular; C) right mandible without row of thin setae at inner margin of innermost denticle; D) fore femur length 3.4 × maximum width, dorsal margin with 10-19 curved, spine-like setae; E) hind protoptera well developed; F) paraproct distally not expanded, with ca. 15 stout, marginal spines.

Description.

Larva (Figs 3 , 4 , 41a ). Body length 4.8-6.5 mm. Cerci ca. ½ of body length. Paracercus ca. 2/3 of cerci length. Antenna approx. twice as long as head length.

Colouration. Head, thorax, and abdomen dorsally brown with bright pattern as in Fig. 41a , fore protoptera light brown with darker striation. Head, thorax, and abdomen ventrally light brown. Legs light brown, femur basally and apically brown with a distomedial brown spot and a brown streak distomedially along dorsal margin, tibia basally with brown area, tarsus medially brown. Caudalii light brown with a brown band both at base and at ca. 1/3 of cerci length, cerci distally brown.

Antenna (Fig. 4g ) with scape and pedicel subcylindrical, with well-developed distolateral process at scape.

Labrum (Fig. 3a, b ). 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 6-8 long, dendritic setae. Ventrally with marginal row of setae composed of anterolateral long, feathered setae and medial long, bifid, pectinate setae; ventral surface with ca. six short, spine-like setae near lateral and anterolateral margin.

Right mandible (Fig. 3c, d, e ). Incisor and kinetodontium fused. Incisor with five denticles; kinetodontium with three denticles, inner margin of innermost denticle without a row of thin setae; denticles of both incisor and kinetodontium of unused mandibles with secondary dentation. Prostheca robust, apically denticulate. Margin between prostheca and mola slightly convex. Tuft of setae at apex of mola present.

Left mandible (Fig. 3f, g ). Incisor and kinetodontium fused. Incisor with four denticles; kinetodontium with three denticles. Prostheca robust, apically with small denticles and comb-shaped structure. Margin between prostheca and mola slightly convex. 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 slightly convex. Basal half with fine, simple setae scattered over dorsal surface.

Hypopharynx and superlinguae (Fig. 3h ). Lingua approx. as long as superlinguae. Lingua longer than broad; medial tuft of stout setae poorly developed; distal half laterally expanded. Superlinguae distally rounded; lateral margin rounded; fine, long, simple setae along distal margin.

Maxilla (Fig. 3i ). Galea-lacinia ventrally with two simple, apical setae under canines. 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 medium to long, simple setae. Maxillary palp approx. as long as length of galea-lacinia; 2-segmented; palp segment II 1.6 × length of segment I; setae on maxillary palp fine, simple, scattered over surface of segments I and II; apex of last segment slightly pointed, with slight excavation at inner distolateral margin.

Labium (Fig. 3j, k ). Glossa basally broad, narrowing toward apex; shorter than paraglossa; inner margin with ca. ten spine-like setae increasing in length distally; apex with two long, robust, pectinate setae and one short, robust seta; outer margin with three spine-like setae; ventral surface with fine, simple, scattered setae. Paraglossa sub-rectangular, curved inward; apex rounded; with three rows of long, robust, distally pectinate setae in apical area and 4-6 medium, simple setae in anteromedial area; outer, anterolateral margin with some long, spine-like setae; dorsally with a row of three long, spine-like setae near inner margin. Labial palp with segment I 0.9 × length of segments II and III combined. Segment I ventrally with short, fine, simple setae. Segment II with slender, thumb-like distomedial protuberance; distomedial protuberance 0.5 × width of base of segment III; ventral surface with short, fine, simple setae; dorsally with two or three spine-like, simple setae near outer margin. Segment III subrectangular; length 0.9 × width; ventrally covered with short, spine-like, simple setae and short, fine, simple setae.

Hind protoptera (Fig. 4h ) well developed.

Foreleg (Fig. 4a-c ). Ratio of foreleg segments 1.4:1.0:0.7:0.3. Femur. Length ca. 3 × maximum width. Dorsal margin with a row of 10-19 curved, spine-like setae, apically rounded and sometimes with minute dentation; length of setae 0.13 × maximum width of femur. Apex rounded, with a pair of spine-like setae, apically rounded and sometimes with minute dentation and some short, stout setae. Many stout, lanceolate setae scattered along ventral margin; femoral patch present. Tibia. Dorsal margin with two rows of short, spine-like setae. Ventral margin with a row of short, curved, spine-like setae, on apex some longer, partly bipectinate, spine-like setae and a tuft of fine, simple setae. Anterior surface scattered with stout, lanceolate setae. Patellotibial suture present on basal 2/3 area. Tarsus. Dorsal margin with one or two rows of short, stout setae. Ventral margin with a row of curved, spine-like setae. Claw with one row of 13-15 denticles; distally pointed; with five or six stripes; subapical setae absent.

Terga (Fig. 4d ). Surface with irregular rows of W-shaped scale bases and scattered fine, simple setae. Posterior margin of tergum IV with triangular spines, longer than wide.

Gills (Fig. 4e ). Present on segments I-VII. Margin with small denticles intercalating fine simple setae. Tracheae extending from main trunk to inner and outer margins. Gill I ca. 2/3 length of segment II. Gill IV as long as length of segments V and 2/3 VI combined. Gill VII as long as length of segments VIII and 1/3 IX combined.

Paraproct (Fig. 4f ). Distally not expanded, with ca. 15 stout, marginal spines. Surface scattered with U-shaped scale bases and fine, simple setae. Cercotractor with numerous small, marginal spines.

Etymology.

Named after the Filipino word Labiobaetis dalisay meaning pristine, which describes the localities where the species was collected.

Distribution.

Philippines: Luzon (Fig. 48b ).

Biological aspects.

The specimens were collected at altitudes from 60 m to 400 m, mainly in pristine areas.

Type material.

Holotype. Philippines • larva; Luzon, Maria Aurora, Wenceslao, Bingwangan River; 15°45'48"N, 121°25'21"E; 60 m; 05.II.1998; leg. Mendoza; on slide; GBIFCH 00592279; PNM. Paratypes. Philippines • larva; Luzon, Nueva Ecija, Pantabangan, Candaclan River; 15°46'48"N, 121°13'17"E; 240 m; 05.II.1998; leg. Mendoza; on slide; GBIFCH 00654909; ZSM • 6 larvae; Luzon, Benguet, Tuba, Taloy Sur; 16°21'33"N, 120°30'31"E; 400 m; XI. 1997; leg. Mey; 1 on slide; GenBank: MT830940; GBIFCH 00763649; AdMU; 5 in alcohol; GBIFCH 00515405; MZL.

Figures

Figure 3. Labiobaetis dalisay sp. nov., larva morphology a labrum b seta of arc on dorsal surface of labrum c right mandible d right prostheca e right incisor and kinetodontium f left mandible g left prostheca h hypopharynx and superlinguae i maxilla j labium k apex of paraglossa.

Figure 4. Labiobaetis dalisay sp. nov., larva morphology a foreleg b seta at apex of femur c fore claw d tergum IV e gill IV f paraproct g antennal scape h metanotum.

Figure 41. Habitus, larvae, dorsal view a Labiobaetis dalisay sp. nov. b Labiobaetis acei sp. nov. c Labiobaetis aldabae sp. nov.

Figure 48. Distribution of Labiobaetis in the Philippines a Philippines, overview b Group Labiobaetis dendrisetis c Group Labiobaetis numeratus.