Labiobaetis giselae, 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 giselae sp. nov. Figures 37 , 38 , 45c , 49c

Diagnosis.

Larva. Following combination of characters: A) dorsal surface of labrum with submarginal arc of three long, lanceolate setae; B) labial palp segment II with a hook-like distomedial protuberance, segment III conical; C) hypopharynx with well-developed medial tuft of long, stout setae, setae apically with minute serration; D) fore femur rather broad, length 2.6 × maximum width, dorsal margin with ca. 12 long, curved, spine-like setae and a second row of spine-like setae near margin; E) paraproct distally expanded with ca. six stout, marginal spines; F) paracercus short, ca. ¼ of cerci length.

Description.

Larva (Figs 37 , 38 , 45c ). Body length 3.4-4.5 mm. Cerci ca. 2/3 of body length. Paracercus ca. 1/4 of cerci length. Antenna approx. twice as long as head length.

Colouration. Head and pronotum dorsally brown, meso- and metanotum light brown, fore protoptera light brown with brown apex. Abdominal segments II-VI dorsally dark brown, segments I and VII-X light brown, segments VII and X with brown markings as in Fig. 45c . Head and thorax ventrally light brown, abdominal segments II-VI ventrally dark brown, segments I and VII-X light brown, segment IX with brown anterior margin and segment X laterally darker. Femur ecru with a distomedial brown spot connected to brown streaks at dorsal and ventral margin and a basal brown area; tibia and tarsus light brown. Caudalii light brown.

Antenna (Fig. 38g ) with scape and pedicel subcylindrical, without distolateral process at scape.

Labrum (Fig. 37a ). Rectangular, length 0.6 × 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 three long, lanceolate setae. Ventrally with marginal row of setae composed of anterolateral long, feathered setae and medial long, bifid setae; ventral surface with ca. four short, spine-like setae near lateral and anterolateral margin.

Right mandible (Fig. 37b, c ). Incisor and kinetodontium fused. Incisor with five denticles; kinetodontium with four denticles, inner margin of innermost denticle without 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. 37d, e ). Incisor and kinetodontium fused. Incisor with five denticles; kinetodontium with four denticles. Prostheca robust, apically with small denticles and comb-shaped 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 slightly convex. Basal half with fine, simple setae scattered over dorsal surface.

Hypopharynx and superlinguae (Fig. 37f-h ). Lingua approx. as long as superlinguae. Lingua longer than broad; medial tuft of stout setae well developed, long, setae apically with minute serration; distal half laterally expanded. Superlinguae distally rounded; lateral margin rounded; fine, long, simple setae along distal margin.

Maxilla (Fig. 37i ). 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 spine-like, pectinate seta and one long, simple seta. Maxillary palp 1.6 × as long as length of galea-lacinia; 2-segmented; palp segment II 1.1 × 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. 37j, k ). Glossa basally broad, narrowing toward apex; shorter than paraglossa; inner margin with ca. four spine-like setae, distalmost seta much longer than other setae; apex with two long and one medium, robust, pectinate setae; outer margin with five long, spine-like setae; ventral surface with short, fine, simple and short, spine-like setae. Paraglossa sub-rectangular, curved inward; apex rounded; with three rows of long, robust, distally pectinate setae in apical area; dorsally with two or 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 hook-like distomedial protuberance; distomedial protuberance 0.5 × width of base of segment III; ventral surface with short, fine, simple setae; dorsally with one long, spine-like seta near outer margin. Segment III conical; apex slightly pointed; length 1.0 × width; ventrally covered with short, spine-like, simple setae and short, fine, simple setae.

Hind protoptera absent.

Foreleg (Fig. 38a, b ). Ratio of foreleg segments 1.2:1.0:0.6:0.2. Femur. Length ca. 3 × maximum width. Dorsal margin with ca. 12 long, curved, spine-like setae and a second row of long, spine-like setae near margin; length of setae 0.29 × maximum width of femur. Apex rounded, with a pair of curved, spine-like setae. Many stout, lanceolate setae scattered along ventral margin; femoral patch absent. Tibia. Dorsal margin with a row of fine, simple setae. Ventral margin with a row of short, curved, spine-like setae, on apex one longer, spine-like seta and a tuft of fine, simple setae. Anterior surface scattered with stout, lanceolate setae. Patellotibial suture present on basal half. Tarsus. Dorsal margin with a row of fine, simple setae. Ventral margin with a row of curved, spine-like setae. Claw with one row of 12 or 13 denticles; distally pointed; with ca. four stripes; subapical setae absent.

Terga (Fig. 38c ). Surface with scattered micropores. Posterior margin of tergum IV with triangular spines, approx. as long as wide.

Gills (Fig. 38d ). Present on segments II-VII. Margin with small denticles intercalating fine simple setae. Tracheae extending from main trunk to inner and outer margins. Gill IV as long as length of segments V and 1/3 VI combined. Gill VII as long as length of segments VIII and 1/3 IX combined.

Paraproct (Fig. 38e, f ). Distally expanded, with ca. six stout, marginal spines. Surface scattered with short, broad, lanceolate setae and micropores. Cercotractor with numerous broad, marginal spines, apically denticulate.

Etymology.

Dedicated to the late Mrs. Gisela Horzel (Germany), mother of one of the authors (TK).

Distribution.

Philippines: Luzon (Fig. 49c ).

Biological aspects.

The specimens were collected at an altitude of 240 m on bottom gravel in runs or riffles.

Type material.

Holotype. 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 00592280; PNM. Paratypes. Philippines • 4 larvae; same data as holotype; 2 on slides; GenBank: MT830984; GBIFCH 00654911, GBIFCH 00515469; ZSM; 2 in alcohol; GBIFCH 00515482; AdMU.

Figures

Figure 37. Labiobaetis giselae sp. nov., larva morphology a labrum b right mandible c right prostheca d left mandible e left prostheca f hypopharynx and superlinguae g hypopharynx, detail of tuft of stout setae h hypopharynx, seta of tuft of stout setae i maxilla j labium k apex of paraglossa.

Figure 38. Labiobaetis giselae sp. nov., larva morphology a foreleg b fore claw c tergum IV d gill IV e paraproct f seta of paraproct g antennal scape.

Figure 45. Habitus, larvae, dorsal view a Labiobaetis freitagi sp. nov. b Labiobaetis pelingeni sp. nov. c Labiobaetis giselae sp. nov. d Labiobaetis mendozai sp. nov.

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