Papuanatula ( Fijifiliola ) crussetae, Kaltenbach, 2025

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

Papuanatula ( Fijifiliola) crussetae sp. nov.

Figs 18 , 19 , 20

Material examined.

Holotype. FIJI • larva; Viti Levu , Ba Prov. , near Abaca village, Savuione Riv., close below Savuione waterfall; 17 ° 40 ' 26 " S, 177 ° 33 ' 06 " E; 690 m; 24. x. 2024; leg. T. Kaltenbach; on slides; GBIFCH 01581936, GBIFCH 01582032; MZL.

Diagnosis.

Larva. Following combination of characters distinguishes P. crussetae sp. nov. from other species of Fijifiliola subgen. nov.: femur with irregular row of medium to long, spine-like setae at outer margin; tibia with irregular row of medium, spine-like setae parallel to row of long, fine, simple setae; distalmost seta at inner margin of tarsus not much longer than other setae; claw with one row of 16–19 denticles; tergalii in large middle part brown; paracercus with five segments.

Description.

Larva (Figs 18 – 20 ). Body length 4.7 mm, cerci longer than body length.

Colouration (Fig. 18 a – c ). Head and thorax dorsally dark grey-brown with indistinct grey pattern; abdomen dorsally dark grey-brown to reddish brown, darker in middle part and laterally, terga IX and X brighter. Legs dark grey; femur on anterior side in basal ½ with large, dark brown, hypodermal, oval marking in large blank, distomedially reddish brown. Thorax ventrally off-white, abdomen ventrally yellowish grey. Caudalii grey.

Head. Antenna (Fig. 19 h ). Length ~ 1.5 × head length. As typical for subgenus.

Labrum (Fig. 19 a, b ). Length 0.7 × maximum width. Otherwise, as typical for subgenus.

Right mandible (Fig. 19 f ). Margin between prostheca and mola straight, with few minute denticles. Otherwise, as typical for subgenus.

Left mandible (Fig. 19 e ). Margin between prostheca and mola slightly convex, with few minute denticles. Otherwise, as typical for subgenus.

Hypopharynx and superlinguae (Fig. 19 d ). As typical for subgenus.

Maxilla (Fig. 19 g ). Maxillary palp approx. as long as galea-lacinia; palp segment II ~ 1.2 × longer than segment I. Otherwise, as typical for subgenus.

Labium (Fig. 19 c ). Paraglossa with two spine-like setae on inner, distolateral margin. Labial palp with segment I subequal to length of segments II and III combined. Segment II dorsally with row of six spine-like setae near outer, distolateral margin. Segment III slightly pentagonal, 0.8 × length of segment II. Otherwise, as typical for subgenus.

Legs (Fig. 20 a – g ). Ratio of leg segments: fore leg 1.2: 1.0: 0.5: 0.2, middle leg 1.2: 1.0: 0.4: 0.2 and hind leg 1.2: 1.0: 0.5: 0.2. Femur. Length ~ 2.2 × maximum width on foreleg, other legs ~ 2.5 ×. Outer margin with irregular row of medium to long, spine-like setae. Short, pointed, spine-like setae along ventral margin. Tibia. With irregular row of short to medium, spine-like setae parallel to row of long, fine, simple setae. Tarsus. Outer margin with irregular row of short to medium, spine-like setae parallel to row of long, fine, simple setae, similar to tibia. Distalmost seta at inner margin not much longer than other setae. Claw with one row of 16–19 denticles; one or two posterior setae. Otherwise, as typical for subgenus.

Abdomen. Terga (Fig. 20 i, j ). Posterior margin of terga: I smooth, without denticles; II – IX with triangular denticles.

Tergalii (Fig. 20 l, m ). Wide skewed oval in shape; tracheation well-developed, reaching margins, brown; scattered brown hypodermal pigmentation in large middle part. Margin with minute denticles and medium, fine, simple setae.

Paraproct (Fig. 20 k ). Posterior margin without prolongation, smooth, without denticles. Cercotractor without denticles.

Caudalii (Fig. 19 i, j ). Cerci without swimming setae. Paracercus with five segments.

Pose of subimaginal gonostyli under larval cuticle. Unknown.

Subimago. Unknown.

Imago. Unknown.

Egg. Unknown.

Biological aspects.

Local species; larvae living in run of fast flowing, turbulent mountain rivers with pristine water (Fig. 36 d ).

Etymology.

The species name is based on the Latin words crus and setae, meaning leg bristles, referring to the extraordinary setation of the legs.

Distribution.

Fiji: Viti Levu (Fig. 39 f ).

Figures

Figure 18. Papuanatula (Fijifiliola) crussetae sp. nov., larva, habitus. a. Dorsal view; b. Lateral view; c. Ventral view. Scale bars: 1 mm.

Figure 19. Papuanatula (Fijifiliola) crussetae sp. nov., larva. a, b. Labrum; c. Labium; d. Hypopharynx and superlinguae; e. Left mandible; f. Right mandible; g. Maxilla; h. Head; i. Paracercus; j. Cercus. Scale bars: 100 µm (h); 20 µm (a, c – g, i); 10 µm (b, j).

Figure 20. Papuanatula (Fijifiliola) crussetae sp. nov., larva. a. Middle leg; b. Femur, outer margin; c. Femur, inner margin; d. Tibia, outer margin; e. Tibia, inner margin; f. Tarsus, outer margin; g. Tarsus, inner margin; h. Claw (arrow: posterior seta); i. Abdomen; j. Abdominal terga; k. Paraproct; l, m. Tergalius VI. Scale bars: 100 µm (i); 50 µm (a, l); 10 µm (b – h, j, k, m).

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 39. Distribution of described species. a. Baetis procul sp. nov. (locations B, I); b. Papuanatula (Fijifiliola) aji sp. nov. (locations A, B, C, C 1, D, E, E 1, F, I); c. Papuanatula (Fijifiliola) aurantica sp. nov. (location G); d. Papuanatula (Fijifiliola) bula sp. nov. (locations D, D 1, G, H); e. Papuanatula (Fijifiliola) claudia sp. nov., Papuanatula (Fijifiliola) flowersi sp. nov. (locations C, C 1); f. Papuanatula (Fijifiliola) crussetae sp. nov. (location C).