Papuanatula ( Fijifiliola ) grisea, Kaltenbach, 2025

Kaltenbach, Thomas, 2025, Mayflies of the Fiji Islands (Ephemeroptera), ZooKeys 1259, pp. 205-276 : 205-276

Papuanatula ( Fijifiliola) grisea sp. nov.

Figs 27 , 28 , 29

Material examined.

Holotype. FIJI • larva; Viti Levu , Ba Prov., Ba Riv., near Outback Hotel; 17 ° 37 ' 35 " S, 177 ° 45 ' 04 " E; 20 m; 22. x. 2024; leg. T. Kaltenbach; on slide; GBIFCH 01582000; MZL . Paratypes. • 4 larvae; same data as holotype; 3 on slides; GBIFCH 01581958, GBIFCH 01581959, GBIFCH 01221840, GBIFCH 01221836 (gonostylus); 1 in alcohol; GBIFCH 01582030; MZL • 4 larvae; Viti Levu , Ba Prov., Ba Riv., near Outback Hotel; 17 ° 37 ' 35 " S, 177 ° 45 ' 04 " E; 20 m; 21. x. 2024; leg. T. Kaltenbach; 1 on slide; GBIFCH 01581940; 2 in alcohol; GBIFCH 01582011, GBIFCH 01582029; MZL • 2 larvae; Viti Levu , Ba Prov., Sabeto Riv., near Sabeto; 17 ° 43 ' 09 " S, 177 ° 31 ' 21 " E; 30 m; 17. xi. 2024; leg. T. Kaltenbach; 1 on slide; GBIFCH 01581972; 1 in alcohol; GBIFCH 01582026; MZL .

Diagnosis.

Larva. Following combination of characters distinguishes P. grisea sp. nov. from other species of Fijifiliola subgen. nov.: larva dorsally grey; legs grey, femur on anterior side in basal part with reddish brown, hypodermal streak (poorly developed on middle leg, nearly absent on hind leg) in large, wedge-shaped blank; labial palp segment III slightly pentagonal; paracercus with 10–15 segments; cerci with 1–5 swimming setae in middle part.

Description.

Larva (Figs 27 – 29 ). Body length 3.0– 3.4 mm, cerci subequal to body length.

Colouration (Fig. 27 a – c ). Head, thorax and abdomen dorsally grey with indistinct pattern as in Fig. 27 a , fore protoptera grey. Legs grey, femur on anterior side in basal part with reddish brown, hypodermal streak (poorly developed on middle leg, nearly absent on hind leg) in large, wedge-shaped blank, medially with dark brown marking; femur on posterior side yellowish grey, without marking. Head, thorax and abdomen ventrally light grey. Caudalii grey.

Head. Antenna (Fig. 28 j ). Length ~ 1.5 × head length. As typical for subgenus.

Labrum (Fig. 28 a, b ). Length 0.5 × maximum width. Otherwise, as typical for subgenus.

Right mandible (Fig. 28 f ). Margin between prostheca and mola straight, with few minute denticles. Otherwise, as typical for subgenus.

Left mandible (Fig. 28 e ). Margin between prostheca and mola straight, with few minute denticles toward subtriangular process. Otherwise, as typical for subgenus.

Hypopharynx and superlinguae (Fig. 28 d ). As typical for subgenus.

Maxilla (Fig. 28 g ). Maxillary palp slightly longer than galea-lacinia; palp segment II subequal to length of segment I. Otherwise, as typical for subgenus.

Labium (Fig. 28 c ). Paraglossa with one spine-like seta on inner, distolateral margin. Labial palp with segment I ~ 1.4 × length of segments II and III combined. Segment II dorsally with row of four spine-like setae near outer, distolateral margin. Segment III slightly pentagonal, 0.6 × length of segment II. Otherwise, as typical for subgenus.

Legs (Fig. 29 a – e ). Ratio of leg segments: fore leg 0.9: 1.0: 0.3: 0.2, middle leg 1.0: 1.0: 0.4: 0.2 and hind leg 1.1: 1.0: 0.4: 0.2. Femur. Length ~ 3 × maximum width. Tibia. With row of short, blunt setae on each side parallel to row of long, fine, simple setae. Claw with one row of 10–12 denticles; one posterior setae. Otherwise, as typical for subgenus.

Abdomen. Terga (Fig. 29 f, g ). Posterior margin of terga: I smooth, without denticles, II – IX with triangular, partly split denticles.

Tergalii (Fig. 29 i ). Elongate oval; tracheation mainly limited to main trunk, dark brown. Margin smooth, with short, fine, simple setae.

Paraproct (Fig. 29 h ). Posterior margin with prolongation, with split denticles.

Caudalii (Fig. 28 h, i ). Cerci with 1–5 swimming setae in middle part. Paracercus with 10–15 segments.

Pose of subimaginal gonostyli under larval cuticle (Fig. 28 k ). As typical for subgenus.

Subimago. Unknown.

Imago. Unknown.

Egg. Unknown.

Biological aspects.

Larvae living in run or riffles of medium fast flowing lowland rivers (Figs 36 b, c , 37 b ).

Etymology.

The species name refers to the predominant grey colour, which distinguishes it easily from the often co-occurring species P. aji sp. nov.

Distribution.

Fiji: Viti Levu (Fig. 40 b ).

Figures

Figure 27. Papuanatula (Fijifiliola) grisea sp. nov., larva, habitus. a. Dorsal view; b. Lateral view; c. Ventral view. Scale bars: 1 mm.

Figure 28. Papuanatula (Fijifiliola) grisea sp. nov., larva. a, b. Labrum; c. Labium; d. Hypopharynx and superlinguae; e. Left mandible; f. Right mandible; g. Maxilla; h. Paracercus; i. Cercus; j. Head; k. Male mature larva, developing subimaginal gonostylus. Scale bars: 100 µm (j); 50 µm (c); 20 µm (e – h); 10 µm (b, d, i, k).

Figure 29. Papuanatula (Fijifiliola) grisea sp. nov., larva. a. Fore leg; b. Femur, outer margin; c. Tibia; d. Tarsus; e. Claw; f. Abdomen; g. Abdominal terga; h. Paraproct; i. Tergalius IV. Scale bars: 100 µm (f); 50 µm (a); 10 µm (b – e, g – i).

Figure 36. Habitats. a. Overview map; b, c. Ba River near Outback Hotel (locations A, B; lowland river); d. Savuione River, close to beyond the Savuione waterfall, near Abaca village (location C; mountain river); e. Savuione River, downstream of the waterfall, near Abaca village (location C 1; mountain river). For characteristics of locations see Table 3.

Figure 37. Habitats. a. Creek near Outback Hotel (location D 1); b. Sabeto River, near Sabeto (location I; lowland river); c. Biausevu River, near Biausevu (location G); d. Waisila creek, Colo-I-Suva Forest Park (location H). Characteristics of locations see Table 3.

Figure 40. Distribution of described species. a. Papuanatula (Fijifiliola) gattolliati sp. nov. (locations E, F); b. Papuanatula (Fijifiliola) grisea sp. nov. (locations A, B, I); c. Papuanatula (Fijifiliola) sekawa sp. nov. (location E); d. Papuanatula (Fijifiliola) tenebris sp. nov. (location C 1).