Labiobaetis wantzeni, 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 wantzeni sp. nov. Figures 25 , 26 , 44b , 49a

Diagnosis.

Larva. Following combination of characters: A) dorsal surface of labrum with submarginal arc of one plus 7-10 long, feathered setae; 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 a row of ca. 18 curved, spine-like setae; D) claw with 10-13 denticles; E) hind protoptera medium developed; F) paraproct distally not expanded, with ca. 30 stout marginal spines.

Description.

Larva (Figs 25 , 26 , 44b ). Body length 5.2-7.1 mm. Cerci ca. 2/3 of body length. Paracercus ca. 2/3 of cerci length. Antenna approx. 2.5 × as long as head length.

Colouration. Head dorsally light brown, thorax and abdomen dorsally mainly dark brown with pattern as in Fig. 44b , abdominal segments I, VI, and X light brown; fore protoptera basally dark brown, distally light brown with bright striation. Head, thorax, and abdomen ventrally mainly light brown, genae dark brown, abdominal segments laterally with darker areas and abdominal segments VII-IX dark brown. Legs light brown, femur with distomedial and apical dark brown spots, tibia distally with dark brown area. Caudalii light brown with a brown band at ca. 1/3 of cerci length, cerci distally brown.

Antenna (Fig. 26f ) with scape and pedicel subcylindrical, with well-developed distolateral process at scape.

Labrum (Fig. 25a ). 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 7-10 long, feathered setae. Ventrally with marginal row of setae composed of lateral and anterolateral long, feathered setae and medial long, bifid, pectinate setae; ventral surface with ca. four short, spine-like setae near lateral and anterolateral margin.

Right mandible (Fig. 25b, 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. 25d, 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 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. 25f ). Lingua approx. as long as superlinguae. Lingua longer than broad; medial tuft of stout setae well developed, short; distal half laterally expanded. Superlinguae distally rounded; lateral margin rounded; fine, long, simple setae along distal margin.

Maxilla (Fig. 25g ). 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 1.2 × as long as length of galea-lacinia; 2-segmented; palp segment II 1.5 × length of segment I; setae on maxillary palp fine, simple, scattered over surface of segments I and II; apex of last segment rounded, with excavation at inner distolateral margin.

Labium (Fig. 25h ). Glossa basally broad, narrowing toward apex; shorter than paraglossa; inner margin with ca. 8 spine-like setae increasing in length distally; apex with two long, one medium and one short, robust 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 and one or 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 0.8 × 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 two or three spine-like, simple setae near outer margin. Segment III conical; apex rounded; length 0.9 × width; ventrally covered with short, spine-like, simple setae and short, fine, simple setae.

Hind protoptera (Fig. 26g, h ) medium to well developed.

Foreleg (Fig. 26a, b ). Ratio of foreleg segments 1.3:1.0:0.5:0.2. Femur. Length ca. 3 × maximum width. Dorsal margin with a row of 15-18 curved, spine-like setae, sometimes a few extra setae basally near margin; length of setae 0.14 × maximum width of femur. Apex rounded, with one or two pairs 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, near margin another row of short, spine-like setae. Ventral margin with a row of short, spine-like setae, on apex some longer spine-like 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. Ventral margin with a row of curved, spine-like setae and in distal area fine simple setae. Claw with one row of 10-13 denticles; distally pointed; with ca. six stripes; subapical setae absent.

Terga (Fig. 26c ). Surface with irregular rows of U-shaped scale bases and scattered fine, simple setae. Posterior margin of tergum IV with triangular spines, mainly longer than wide.

Gills (Fig. 26d ). 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 half VI combined. Gill VII as long as length of segments VIII and 1/4 IX combined.

Paraproct (Fig. 26e ). Distally not expanded, with ca. 30 stout, marginal spines. Surface scattered with U-shaped scale bases, fine, simple setae and micropores. Cercotractor with numerous small, marginal spines.

Etymology.

Dedicated to Prof. Karl Matthias Wantzen (France), collector of some material, for his outstanding contribution to freshwater ecological research and conservation.

Distribution.

Philippines: Camiguin and Mindanao (Fig. 49a ).

Biological aspects.

The specimens were collected at altitudes from sea level to 900 m, on bottom gravel, submerged wood, leaf packs or grass bunches in runs or riffles.

Type material.

Holotype. Philippines • larva; Camiguin, Sagay, Bonbon, lower Binangawan River; 09°06'39"N 124°43'45"E; 30 m; 09.XII.2018; leg. Freitag and Wantzen; on slide; GenBank: MT830968; GBIFCH 00654898; PNM. Paratypes. Philippines • 8 larvae; same data as holotype; 3 on slides; GenBank: MT830973, MT830969, MT830972; GBIFCH 00654900, GBIFCH 00654897, GBIFCH 00654896; ZSM; 1 on slide; GBIFCH 00592276; AdMU; 2 in alcohol; GBIFCH 00515412, GBIFCH 00515413; AdMU; 2 in alcohol; GBIFCH 00515416, GBIFCH 00515417; ZSM • 2 larvae; Camiguin, Looc /Tuasan R, ca. 9.5 km SE Mambajao; 09°12'N, 124°41'E; 240 m; 08.XII.2018; leg. Freitag; 1 on slide; GBIFCH 00515522; AdMU; 1 on slide; GenBank: MT830970; GBIFCH 00763641; ZSM • 1 larva; Camiguin, Mt. Mabajao Sagay, upstream Binangawan Falls; 09°09'25"N, 124°43'57"E; 900 m; 09.XII.2018; leg. Freitag; in alcohol; GBIFCH 00515414; AdMU • 7 larvae; Mindanao, Ozamis, Tangub, Labo River; 08°09'42"N, 124°42'28"E; 470 m; 13.IV.1994; leg. Mendoza; 1 on slide; GenBank: MT830971; GBIFCH 00763642; ZSM; 6 in alcohol; GBIFCH 00515415; AdMU.

Figures

Figure 25. Labiobaetis wantzeni sp. nov., larva morphology a labrum b right mandible c right prostheca d left mandible e left prostheca f hypopharynx and superlinguae g maxilla h labium.

Figure 26. Labiobaetis wantzeni sp. nov., larva morphology a foreleg b fore claw c tergum IV d gill IV e paraproct f antennal scape g metanotum h metanotum.

Figure 44. Habitus, larvae, dorsal view a Labiobaetis valdezorum sp. nov. b Labiobaetis wantzeni sp. nov. c Labiobaetis baganii sp. nov. d Labiobaetis delocadoi sp. nov.

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