Labiobaetis mendozai, 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 mendozai sp. nov. Figures 39 , 40 , 45d , 49c

Diagnosis.

Larva. Following combination of characters: A) dorsal surface of labrum with submarginal arc of one plus 5-8 long, lanceolate setae; B) labial palp segment II with a slender, thumb-like protuberance, segment III slightly pentagonal with small apical projection; C) hypopharynx with well-developed medial tuft of long, stout setae, setae apically with minute serration; D) fore femur length 3.4 × maximum width, dorsal margin with 8-11 curved, spine-like setae and at least a partial row of spine-like setae near margin; E) paraproct distally expanded, with ca. nine stout, marginal spines; F) paracercus short, ca. 1/4 of cerci length.

Description.

Larva (Figs 39 , 40 , 45d ). Body length 3.2-4.6 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, thorax, and abdomen dorsally brown with bright pattern as in Fig. 45d . Head, thorax, and abdomen light brown. Femur ecru with a distomedial brown spot connected to a brown streak at ventral margin and a light brown basal area. Tibia and tarsus light brown. Caudalii light brown.

Antenna (Fig. 40g ) with scape and pedicel subcylindrical, without distolateral process at scape.

Labrum (Fig. 39a ). Rectangular, length 0.7 × maximum width. Distal margin with medial emargination and a small process. Dorsally with medium to long, fine, simple setae scattered over surface; submarginal arc of setae composed of one plus 5-8 long, lanceolate setae, submedian seta and last seta of arc narrower. Ventrally with marginal row of setae composed of anterolateral long, feathered setae and medial long, bifid setae; ventral surface with ca. three short, spine-like setae near lateral and anterolateral margin.

Right mandible (Fig. 39b, c ). 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. 39d, e ). Incisor and kinetodontium fused. Incisor with five denticles; kinetodontium with three 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. 39f, g ). 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 straight; lateral margin rounded; fine, long, simple setae along distal margin.

Maxilla (Fig. 39h ). 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 two or three long, simple setae. Maxillary palp 1.4 × as long as length of galea-lacinia; 2-segmented; palp segment II 1.3 × 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. 39i ). Glossa basally broad, narrowing toward apex; shorter than paraglossa; inner margin with ca. seven spine-like setae increasing in length distally; apex with two long and one medium, robust, pectinate setae; outer margin with five or six spine-like setae increasing in length distally; 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 three medium, simple setae in anteromedial area; dorsally with a row of three long, spine-like setae near inner margin. Labial palp with segment I 0.6 × length of segments II and III combined. Segment I ventrally with short, fine, simple setae. Segment II with slender, thumb-like, distomedial protuberance, distally bent upward; distomedial protuberance 0.8 × width of base of segment III; ventral surface with short, fine, simple setae; dorsally with a row of 2-4 medium, spine-like setae near outer margin. Segment III slightly pentagonal; apex with small projection; length 1.2 × width; ventrally covered with short, spine-like, simple setae and short, fine, simple setae.

Hind protoptera absent.

Foreleg (Fig. 40a-c ). Ratio of foreleg segments 1.2:1.0:0.4:0.1. Femur. Length ca. 3 × maximum width. Dorsal margin with 8-11 curved, spine-like setae and at least a partial row of spine-like setae near margin; length of setae 0.27 × 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 1/3. Tarsus. Dorsal margin with a row of fine, simple setae. Ventral margin with a row of curved, spine-like setae with minute marginal pectination (pectination difficult to see). Claw with one row of ten denticles; distally pointed; with ca. three stripes; subapical setae absent.

Terga (Fig. 40d ). Surface with irregular rows of W-shaped scale bases and scattered micropores. Posterior margin of tergum IV with triangular spines, wider than long.

Gills (Fig. 40e ). 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 half VI combined. Gill VII as long as length of segments VIII and 1/3 IX combined.

Paraproct (Fig. 40f ). Distally expanded, with ca. nine stout, marginal spines. Surface scattered with U-shaped scale bases and fine, simple setae. Cercotractor with numerous broad, marginal spines.

Etymology.

Dedicated to the late Mr. Joseph Mendoza (Philippines), outstanding insect collector.

Distribution.

Philippines: Mindanao (Fig. 49c ).

Biological aspects.

The specimens were collected at altitudes from sea level to 120 m, on bottom gravel or submerged wood, or in leaf litter in side pools.

Type material.

Holotype. Philippines • larva; Mindanao, Surigao del Sur, Tandag, Pangi, Pangi River; 09°06'18"N, 126°08'53"E; 10 m; 30.XI.2018, leg. Pangantihon; on slide; GBIFCH 00592272; PNM. Paratypes. Philippines • 5 larvae; same data as holotype; 1 in alcohol; GBIFCH 00515480; ZSM; 4 in alcohol; GBIFCH 00515481; AdMU • 2 larvae; Mindanao, Agusan del Sur, San Francisco, Bayogan, Tagkunayan Creek; 08°28'N, 125°59'E; 120 m; 05.II.1998; leg. Mendoza; 1 on slide; GBIFCH 00515476; AdMU; 1 on slide; GenBank: MT830985; GBIFCH 654894; ZSM • 1 larva; Mindanao, Surigao del Sur, Tandag, Buenavista River; 09°08'18"N, 126°08'45"E; 80 m; 03.XII.2018; leg. Panganthion; in alcohol; GBIFCH 00515478; ZSM.

Figures

Figure 39. Labiobaetis mendozai sp. nov., larva morphology a labrum b right mandible c right prostheca d left mandible e left prostheca f hypopharynx and superlinguae g hypopharynx, seta of tuft of stout setae h maxilla i labium.

Figure 40. Labiobaetis mendozai sp. nov., larva morphology a foreleg b seta of ventral margin of tarsus c fore claw d tergum IV e gill IV f 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.