Procerobaetis freitagi Kaltenbach & Garces & Gattolliat 2020, gen. et sp. nov.

Procerobaetis freitagi Kaltenbach & Gattolliat gen. et sp. nov.

urn:lsid:zoobank.org:act: 8F16E037-FA56-46C9-BE5F-1530CB545115

Figs 8–11, 13, 14C

Diagnosis: larva

The main diagnostic character is the shape of gills III–VII, with long extended points at the apex (Fig. 10 D–H). The diagnostic characters of all species are summarized in Table 3.

Etymology

P. freitagi gen. et sp. nov. is dedicated to Professor Hendrik Freitag (Ateneo de Manila University) for his outstanding contribution to aquatic insect studies and for leading the passionate group of aquatic entomologists in the Philippines.

Material examined

Holotype

PHILIPPINES • larva; Luzon, Nueva Ecija, Pantabangan, Candaclan River, rural; 15°46.80′ N, 121°13.28′ E; 240 m a.s.l.; 5 Feb. 1998; Mendoza leg.; on slide; voucher: GBIFCH 00592245; PNM.

Paratypes

PHILIPPINES • 1 larva; same collection data as for holotype; on slide; voucher GBIFCH 00515324; ZSM • 1 larva; same collection data as for holotype; on slide; voucher: GBIFCH 00658095; AdMU • 1 larva; same collection data as for holotype; in alcohol; voucher: GBIFCH 00515331; ZSM.

Other material

PHILIPPINES • 1 larva; Oriental Mindoro, Roxas, Barangay San Vicente, lower reach of Taugad River; 12°37.30′ N, 121°22.97′ E; 140 m a.s.l.; 8 Nov. 2018; J. Garces leg.; on slide; voucher: GBIFCH 00515323; ZSM.

Description: larva (Figs 8–11, 13 A–B)

BODY LENGTH. 4.5–4.8 mm.

COLOURATION (Fig. 13A). Head, thorax and abdomen dorsally brown, head and thorax with bright median dorsal suture. Head, thorax and abdomen ventrally light brown, abdominal segments VI to IX gradually darker. Legs transparent, caudal filaments transparent.

Head

ANTENNA (Fig. 10A). Approximately 2× as long as head length; flagellum with lanceolate spines at apex of each segment, longer at inner lateral margin, increasing in length distally until segment IX–XI and decreasing thereafter.

LABRUM (Fig. 8A). Rectangular, length 0.6× maximum width. Distal margin with medial emargination and a small process. Dorsally with some medium, fine, simple setae and some medium, stout, simple setae scattered over surface in proximal area; many long, stout, simple setae in anteromedial area, erratically distributed, not arranged in an arc. Ventrally with marginal row of setae composed of lateral and anterolateral long, feathered setae and medial long, bifid, pectinate setae; ventral surface with about five short, spine-like setae near lateral and anterolateral margin.

RIGHT MANDIBLE (Fig. 8 B–C). Outer and inner set of denticles with 4+1+3 denticles. Margin between prostheca and mola straight, with a row of long, stout setae. Tuft of setae at apex of mola present.

LEFT MANDIBLE (Fig. 8 D–E). Outer and inner set of denticles with 4+3 denticles. Subtriangular process long and slender, above level of area between prostheca and mola. Denticles of mola apically constricted. Setae at apex of mola absent. Both mandibles with lateral margins almost straight. Basal half with fine, simple setae scattered over dorsal surface.

HYPOPHARYNX (Fig. 8F). Lingua shorter than superlingua, longer than broad, with medial tuft of long, stout setae. Superlingua distally almost straight, lateral margin rounded, with fine, long, simple setae along distal margin.

MAXILLA (Fig. 8g). Galea-lacinia with two simple, robust apical setae under crown. Medially with one pectinate, spine-like seta and a row of 5–6 long, simple setae. Maxillary palp 2× as long as length of galea-lacinia; palp segment II 0.7× length of segment I, palp segment III 0.5× length of segment II; setae on maxillary palp fine, simple, scattered over surface of segments I, II and III; apex of last segment rounded.

LABIUM (Fig. 8H). Glossae basally broad, narrowing toward apex, slightly shorter than paraglossae; inner margin with 9–10 spine-like setae; apex with two long and one medium, robust, pectinate setae; outer margin with seven spine-like setae, increasing in length distally; ventral surface with medium, fine, simple, scattered setae. Paraglossae sub-rectangular, apically curved inward; apex rounded, with three rows of long, robust setae; ventrally two medium, simple setae in anteromedial area; dorsally with a row of five long, spine-like setae near inner margin. Labial palp with segment I 0.9× length of segments II and III combined, ventrally with scattered short, fine, simple setae; segment II with very small distomedial expansion, ventrally with scattered short, fine, simple setae, dorsally with a row of 4–6 long, spine-like setae; segment III subquadrangular, apex rounded, ventrally covered with short spine-like, simple setae and short, fine, simple setae. Mentum distally with scattered fine, simple setae.

Thorax

FORELEG (Figs 9 A–G, 11A). Ratio of foreleg segments 1.4:1.0:1.0:0.3. Femur. Length 3.5–3.8× maximum width; dorsal margin with a row of 6–7 curved, spine-like setae; length of setae 0.25× maximum width of femur; apex rounded, with one pair of spine-like setae; many stout, lanceolate, laterally pectinate setae scattered along ventral margin; femoral patch absent. Tibia. Dorsal margin with a row of fine, simple setae; ventral margin with a row of curved, laterally pectinate, spine-like setae, at apex some longer, laterally pectinate, spine-like setae; anterior surface with scattered stout, lanceolate, laterally pectinate setae; patellotibial suture present on basal ⅓. Tarsus. Dorsal margin with a row of fine, simple setae; ventral margin with a row of curved, laterally pectinate, spine-like setae; tarsal claw elongate, slender, apically pointed, with one row of 7–10 larger denticles and many minute denticles, ventral margin at apex straight, with many stripes.

MIDDLE LEG (Fig. 11B). As foreleg, but dorsal margin of femur slightly concave.

HIND LEG (Fig. 11C). As foreleg, but dorsal margin of femur slightly concave and tarsal claw with one row of 10–12 larger denticles and many minute denticles.

Abdomen

TERGITES (Fig. 9H). Surface with scattered scales, U-shaped scale bases and micropores. Posterior margin of tergites VIII and IX with triangular spines.

GILLS (Fig. 10 B–H). Present on segments I–VII; elongate, with very long, extended points; margin with very small denticles intercalating fine, simple setae; tracheae limited to main trunk. Gill I as long as length of segments II and III combined, gill II as long as length of segments III and ⅔ of IV combined, gill III as long as length of segments IV and V combined, gill IV as long as length of segments V and VI combined, gill V as long as length of segments VI and VII combined, gill VI as long as length of segments VII and VIII combined, gill VII as long as length of segments VIII to X combined.

PARAPROCT (Fig. 9I). Posterior margin with 10–14 stout spines; surface with scattered U-shaped scale bases; posterolateral extension (cercotractor) with numerous small, marginal spines.

CAUDAL FILAMENTS (Fig. 13A). Cerci ca 0.5× body length, median caudal filament ca. 0.8× length of cerci.

Distribution

Philippines: Luzon, Mindoro (Fig. 14C).

Remarks

The specimens were collected at low altitudes from 140 to 240 m a.s.l. in meandering alluvial rivers of small to medium size (width 2–12 m, depth 15–30 cm, water current 0.08–0.80 m /s, temperature 23–28.7°C, pH 6.8–8.3, dissolved oxygen 3.8–8.3 mg /l). The streams are surrounded by secondary vegetation, rarely secondary forest, with a few houses and farmland at some distance from the river bed as described in Garces et al. 2018.

Genetics

COI sequences were obtained from all three of the new species (Table 1). The genetic distances between these species are between 13% and 20%, much higher than 3.5%, which is generally considered as a likely maximal value for intraspecific divergence (Hebert et al. 2003; Ball et al. 2005; Zhou et al. 2010) (Table 4). Very limited genetic distances between 0 and 1% were found between specimens of the same species.