Philibaetis luzonensis ( Mueller-Liebenau , 1982) Kaltenbach & Garces & Gattolliat, 2021

Kaltenbach, Thomas, Garces, Jhoana M. & Gattolliat, Jean-Luc, 2021, Philibaetis gen. nov., a new genus from the Philippines (Ephemeroptera, Baetidae), Deutsche Entomologische Zeitschrift 68 (1), pp. 1-20 : 1

publication ID	https://dx.doi.org/10.3897/dez.68.59462
publication LSID	lsid:zoobank.org:pub:458E5069-2CA2-436A-ABF5-BEFE6EBAC3F0
persistent identifier	https://treatment.plazi.org/id/3A8AA946-8114-5810-8D0C-6441480BA6D1
treatment provided by	Deutsche Entomologische Zeitschrift by Pensoft
scientific name	Philibaetis luzonensis ( Mueller-Liebenau , 1982)
status	comb. nov.

Treatment

Philibaetis luzonensis ( Mueller-Liebenau, 1982) comb. nov. ( Müller-Liebenau 1982 a) Figures 1 View Figure 1 , 2 View Figure 2 , 3 View Figure 3 , 4 View Figure 4 , 5 View Figure 5 , 10a View Figure 10 , 11a-c View Figure 11 , 12 View Figure 12

Differential diagnosis.

Larva. The following characters distinguish P. luzonensis comb. nov. from P. realonae comb. nov.: A) abdominal tergite IV without spines at posterior margin; B) tarsus dorsal margin with row of short, stout setae and fine, simple setae; C) tarsus relatively broad and short, length 4 × width in middle part and length ca. 0.4 × length of tibia; D) claw with mostly three long subapical setae.

Material examined.

Holotype. Philippines • larva; Luzon, Mountain Province, Banaue, Sumigar , Sumigar stream; 03.x.1967; leg. M.L. Pescador; on slide; ZSM.

Other material.

Philippines • 80 larvae; Luzon, Ifugao, Banaue, Sumigar Bridge ; 16°59'37"N, 121°02'51"E; 1700 m alt.; xi. 1997; leg. W. Mey; 3 on slides; GenBank MT873543 View Materials ; GBIFCH 00763652, 00592354, 00515336; MZL; 34 in alcohol; GBIFCH 00515509, 00515516, 00515507, 00515513; MZL; 1 on slide; GenBank MT873545 View Materials ; GBIFCH 00763656; AdMU; 42 in alcohol; GBIFCH 00515512, 00515511, 00515471, 00515508; AdMU GoogleMaps • 27 larvae; Luzon, Mountain Province, Bauko , mineral rich mountain creek; 17°03'53"N, 120°05'10"E; 1820 m alt.; xi. 1997; leg. W. Mey; 1 on slide; GBIFCH 00592353; AdMU; 16 in alcohol; GBIFCH 00515517; AdMU; 2 on slides; GenBank MT873541 View Materials ; GBIFCH 00763644, 00592367; MZL; 8 in alcohol; GBIFCH 00515510, 00515470, 00515506; MZL GoogleMaps ; • 12 larvae; Luzon, Ifugao, Tinoc ; 16°40'58"N, 120°56'59"E; 1400 m alt.; xi. 1997; leg. W. Mey; 7 in alcohol; GBIFCH 00515514, 00515515; AdMU; 1 on slide; GenBank MT873544 View Materials ; GBIFCH 00763653; MZL; 4 in alcohol; GBIFCH 00515524; MZL GoogleMaps .

Description.

Larva. (Figs 1 View Figure 1 - 5 View Figure 5 ). Body length 5.6-9.0 mm (females), 5.6-7.5 mm (males). Cerci little longer than body length, paracercus ca. ½ of cerci length.

Colouration (Fig. 5a-c View Figure 5 ). Head, thorax and abdomen dorsally brown, abdominal segments VI and IX brighter, fore protoptera brown. Head, thorax and abdomen ventrally light brown. Legs with femur and tibia light brown, with darker pattern as in Fig. 5a-c View Figure 5 , tarsus brown. Caudalii light brown.

Head. Antenna (Figs 3d View Figure 3 , 5b View Figure 5 ) with scape and pedicel subcylindrical, length ca. 3 × head length.

Labrum (Fig. 1a-f View Figure 1 ). Rectangular, length 0.6 × maximum width. Distal margin with shallow medial emargination and small process. Dorsally with medium, fine, simple setae scattered over surface; submarginal arc of setae composed of one plus 6-7 long, simple setae. Ventrally with marginal row of setae composed of lateral long, simple setae, anterolateral long, feathered setae and medial long, bifid setae; medially additional, partial, submarginal row of fine, lanceolate setae. Ventral surface with ca. eight short, spine-like setae near lateral margin.

Right mandible (Fig. 1g, h, l View Figure 1 ). Incisor blade-like; kinetodontium with three denticles, inner margin of innermost denticle without row of thin setae; prostheca stick-like, apically denticulate. Margin between prostheca and mola straight. Tuft of setae at apex of mola present.

Left mandible (Fig. 1i-k, m View Figure 1 ). Incisor blade-like; kinetodontium with three denticles. Prostheca apically denticulate and with comb-shaped structure. Margin between prostheca and mola straight, with few minute denticles. Subtriangular process long and slender, above level of area between prostheca and mola. Basally of subtriangular process with tuft of long, partly-branched setae. Tuft of setae at apex of mola present.

Both mandibles with lateral margins convex. Dorsally with fine, simple setae scattered over basal surface and mediolaterally with patch of long, spine-like, simple setae.

Hypopharynx and superlinguae (Fig. 2a View Figure 2 ). Lingua longer than superlinguae, longer than wide; with well-developed medial tuft of stout setae, anterolaterally with two smaller tufts of stout setae. Superlinguae distally almost straight, lateral margins slightly rounded; long, fine, simple setae along distal margin.

Maxilla (Fig. 2b View Figure 2 ). Galea-lacinia ventrally with one simple, apical seta under canines. Inner dorsal row of setae with three denti-setae, distal denti-seta tooth-like and directed against canines, other denti-setae slender, bifid and pectinate. Medially with one spine-like seta and four medium to long, simple setae. Maxillary palp ca. 1.2 × as long as length of galea-lacinia; palp segment II 1.8 × length of segment I; short, fine, simple setae scattered over surface of segments I and II; apex of segment II distally constricted and pointed.

Labium (Fig. 2d, e View Figure 2 ). Glossa basally broad, narrowing towards apex, shorter than paraglossa; inner margin with three medium to long, spine-like, simple setae; outer margin with four long, spine-like, simple setae; apex with two long and one very short, spine-like setae; ventral surface with very few short, fine, simple setae. Paraglossa distally truncate, slightly curved inwards; ventrally with three rows of long, robust, distally-pectinate setae in apical area, row of long, simple setae on anterolateral margin, one short, simple seta in mediolateral area and one robust, bifurcate seta in posterolateral area; dorsally with one long, spine-like seta 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 without protuberance; ventral surface with short, fine, simple setae; dorsally with row of ca. six spine-like setae near outer margin. Segment III almost semicircular; length 0.8 × width; ventrally covered with short, spine-like setae and short to medium, fine, simple setae.

Thorax. Hind protoptera (Fig. 4g View Figure 4 ). Absent.

Foreleg (Figs 3a-c View Figure 3 , 11a-c View Figure 11 ). Ratio of fore femur:tibia:tarsus:claw 1.2:1.0:0.4:0.2. Femur. Rather broad, length ca. 3 × maximum width. Dorsal margin with row of ca. 40 long, curved, spine-like setae; length of setae mostly ca. 0.2 × maximum width of femur. Apex rounded, with several curved, spine-like setae and many short, stout setae; on posterior side, arc of short, stout setae. Stout, lanceolate setae scattered along ventral margin; femoral patch absent. Tibia. Dorsal margin with row of medium, clavate setae. Ventral margin with row of short, spine-like setae, on apex some longer, spine-like setae and tuft of fine, simple setae. Anterior surface scattered with short, stout, lanceolate setae. Patellotibial suture present on basal ¾ area. Tarsus. Dorsal margin with row of short, stout and fine, simple setae. Ventral margin with row of short to medium, curved, spine-like setae. Claw robust and distally pointed, with one row of ca. seven denticles; generally three and sometimes two long, subapical setae.

Abdomen. Tergites (Fig. 4h View Figure 4 ). Surface with irregular rows of U-shaped scale bases, scattered micropores and fine, simple setae along posterior margin. Posterior margin of tergite IV without spines.

Gills (Fig. 4a-d View Figure 4 ). Seven pairs of gills on segments I-VII. Margin with minute denticles intercalating fine, simple setae. Tracheae extending from main trunk to inner and outer margins. Gill I as long as length of half segment II. Gill IV as long as length of segments V and half VI combined. Gill VII as long as length of segment VIII.

Paraproct (Fig. 4e, f View Figure 4 ). Without prolongation at posterior margin, with ca. 16 stout, marginal spines. Surface scattered with U-shaped scale bases and fine, simple setae; with a patch of notched scales. Cercotractor with small, marginal spines.

Protogonostyli (Fig. 10a View Figure 10 ) in male, last instar larvae ready to moult folded under larval cuticle in the Labiobaetis type.

Distribution.

Philippines: Luzon (Fig. 12 View Figure 12 ).

Biological aspects.

The specimens were collected in mountain creeks at altitudes from 1400 m to 1820 m, mainly on bottom gravel or on rock surface in runs or riffles. They ocurred together with Labiobaetis sumigarensis ( Müller-Liebenau, 1982), L. acei Kaltenbach, Garces & Gattolliat, 2020 and L. aldabae Kaltenbach, Garces & Gattolliat, 2020 (see also Müller-Liebenau 1982 a: 77).

Re-description