Labiobaetis tagbanwa, 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 tagbanwa sp. nov. Figures 21 , 22 , 43c , 49a

Diagnosis.

Larva. Following combination of characters: A) dorsal surface of labrum with submarginal arc of one plus 8-10 long, feathered setae with reduced feathers; B) labial palp segment II with a broad thumb-like distomedial protuberance, segment III conical; C) fore femur rather broad, length ca. 3 × maximum width, dorsal margin with ca. 13 curved, spine-like setae; D) hind protoptera medium developed; E) paraproct distally not expanded, with ca. 18 stout, marginal spines.

Description.

Larva (Figs 21 , 22 , 43c ). Body length 4.1-5.3 mm. Cerci ca. 3/4 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 markings as in Fig. 43c , abdominal segments I, VII and X light brown, fore protoptera basally brown, distally light brown with bright striation. Head, thorax, and abdomen ventrally light brown, genae brown, abdominal segments laterally somewhat darker, abdominal segments VIII and IX brown, abdominal segment V, VI and VII medially with darker areas. Legs ecru, femur with distomedial brown spot, apex brown, tibia and tarsus distally light brown. Caudalii light brown, with a brown band at ca. 1/3 of cerci length, cerci distally brown.

Antenna (Fig. 22f ) with scape and pedicel subcylindrical, with well-developed distolateral process at scape.

Labrum (Fig. 21a, b ). Rectangular, length 0.8 × 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 8-10 long, feathered setae with reduced feathers. Ventrally with marginal row of setae composed of lateral and 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. 21c, d ). Incisor and kinetodontium fused. Incisor with five denticles; kinetodontium with three denticles, 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. 21e, f ). 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 almost straight. Basal half with fine, simple setae scattered over dorsal surface.

Hypopharynx and superlinguae (Fig. 21g ). Lingua approx. as long as superlinguae. Lingua longer than broad; medial tuft of stout setae well developed, short; distal half not expanded. Superlinguae distally rounded; lateral margin rounded; fine, long, simple setae along distal margin.

Maxilla (Fig. 21h ). 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 four long, simple setae. Maxillary palp 1.2 × as long as length of galea-lacinia; 2-segmented; palp segment II 1.2 × length of segment I; setae on maxillary palp fine, simple, scattered over surface of segments I and II; apex of last segment rounded, with slight excavation at inner distolateral margin.

Labium (Fig. 21i ). Glossa basally broad, narrowing toward apex; shorter than paraglossa; inner margin with ca. eight spine-like setae; apex with two long and one medium, robust, pectinate setae and one short, robust seta; outer margin with six medium to long spine-like setae; ventral surface with short, simple setae. Paraglossa sub-rectangular, curved inward; apex rounded; with three rows of long, robust, distally pectinate setae in apical area and two medium, simple setae in anteromedial area; dorsally with a row of five long, spine-like, simple 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 broad thumb-like distomedial protuberance; distomedial protuberance 0.5 × width of base of segment III; ventral surface with short, fine, simple setae; dorsally with a row of three or four spine-like, simple setae near outer margin. Segment III conical; apex slightly pointed; length 0.9 × width; ventrally covered with short, spine-like, simple setae and short, fine, simple setae.

Hind protoptera (Fig. 22g ) medium developed.

Foreleg (Fig. 22a, b ). Ratio of foreleg segments 1.5:1.0:0.7:0.3. Femur. Length ca. 3 × maximum width. Dorsal margin with ca. 13 curved, spine-like setae; length of setae 0.18 × maximum width of femur. Apex rounded, with a pair of spine-like setae and some short, stout setae. Many stout, lanceolate setae scattered along ventral margin; femoral patch absent. Tibia. Dorsal margin with a row of short, spine-like setae and fine, simple setae, on apex a pair of longer, spine-like setae. Ventral margin with a row of short, curved, spine-like setae, on apex some longer setae and a tuft of fine, simple setae. Anterior surface scattered with stout, lanceolate setae. Patellotibial suture present on basal 2/3. Tarsus. Dorsal margin with a row of short, stout setae and fine, simple setae. Ventral margin with a row of curved, spine-like setae and in distal area fine simple setae. Claw with one row of 11-14 denticles; distally pointed; with ca. four stripes; subapical setae absent.

Terga (Fig. 22c ). Surface with irregular rows of U-shaped scale bases and scattered fine, simple setae. Posterior margin of tergum IV with triangular spines, wider than long.

Gills (Fig. 22d ). 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. 1/2 length of segment II. Gill IV as long as length of segments V and 1/2 VI combined. Gill VII as long as length of segment VIII.

Paraproct (Fig. 22e ). Distally not expanded, with ca. 18 stout, marginal spines. Surface scattered with U-shaped scale bases and fine, simple setae. Cercotractor with numerous small, marginal spines.

Etymology.

Dedicated to the indigenous Tagbanwa people of Palawan.

Distribution.

Philippines: Palawan (Fig. 49a ).

Biological aspects.

The specimens were collected from sea level to 100 m on rock surface or submerged wood in riffles or runs.

Type material.

Holotype. Philippines • larva; Palawan, Quezon, Aramaywan River, cogon grass; 09°22'33"N, 118°08'41"E; 15 m; 2019; leg. Pangantihon and Pelingen; on slide; GBIFCH 00592324; PNM. Paratypes. Philippines • 16 larvae; same data as holotype; 1 on slide; GenBank: MT830962; GBIFCH 00763680; ZSM, temporarily stored in AdMU; 1 on slide; GBIFCH 00592350; AdMU; 3 in alcohol; GBIFCH 00515432, GBIFCH 00515457; PNM; 2 in alcohol; GenBank: MT830961; GBIFCH 00763681, GBIFCH 00515430; ZSM, temporarily stored in AdMU; 6 in alcohol; GBIFCH 00515431; PCSD; 3 in alcohol; GBIFCH 00515410; AdMU • 1 larva; Palawan, Puerto Princesa, Luzviminda, Iwahig River; 09°41'20"N 118°37'29"E; 13.VI.2009; leg. Freitag; on slide; GenBank: MT830960; GBIFCH 00654885; AdMU • 1 larva; Palawan, Aborlan, Cabigaan, Talakaigan, mount. Riv. upstr. dam; 09°26'55"N, 118°26'44"E; 100 m; 14.VI.1995; leg. Freitag; in alcohol; GBIFCH 00515456; AdMU.

Figures

Figure 21. Labiobaetis tagbanwa sp. nov., larva morphology a labrum b seta of arc on dorsal surface of labrum c right mandible d right prostheca e left mandible f left prostheca g hypopharynx and superlinguae h maxilla i labium.

Figure 22. Labiobaetis tagbanwa sp. nov., larva morphology a foreleg b fore claw c tergum IV d gill IV e paraproct f antennal scape g metanotum.

Figure 43. Habitus, larvae, dorsal view a Labiobaetis gamay sp. nov. b Labiobaetis pangantihoni sp. nov. c Labiobaetis tagbanwa sp. nov.

Figure 49. Distribution of Labiobaetis in the Philippines a Group Labiobaetis operosus b Group Labiobaetis sumigarensis c Group Labiobaetis vallus.