Holotype. Female larva, New Caledonia; Les Koghis, headwaters of Ouanéoué (Loc. 59/2022), -22.1755278, 166.5094167, 510 m a.s.l.; 22.01.2022; leg. J. Bojková, Ľ. Hrivniak. Deposited in MZL. Paratypes. 33 larvae, same data as holotype. Deposited in MZL. 12 larvae, New Caledonia; left tributary of Rivière Bleu, Cornes du diable (Loc. 63/2022), -22.0691111, 166.6130000, 350 m a.s.l.; 22.01.2022; leg. J. Bojková, Ľ. Hrivniak (9 larvae deposited in MZL, 3 larvae mounted on slides and deposited in IECA—DNA extracted). 4 larvae, New Caledonia; Païta, Carignan above villages of Païta (Loc. 56/2022), -22.0785278, 166.3746944, 170 m a.s.l.; 20.01.2022; leg. J. Bojková, Ľ. Hrivniak (2 larvae deposited in MZL; 2 larvae mounted on slides and deposited in IECA—DNA extracted). 4 larvae (1 mounted on slide—DNA extracted), New Caledonia; Route de la Rivière Blanche, unnamed brook, (Loc. 46/2022), -22.1586667, 166.6652222, 175 m a.s.l.; 25.01.2022; leg. J. Bojková, Ľ. Hrivniak. Deposited in IECA. 2 larvae (1 mounted on slide—DNA extracted), New Caledonia; Païta, small brook near the river (Loc. 57/2022), -22.0790556, 166.3742222, 170 m a.s.l.; 20.01.2022; leg. J. Bojková, Ľ. Hrivniak. Deposited in IECA.

Body length of female late-instar larvae 8.0 mm, male 6.0–7.0 mm. Body covered with sparse hair-like setae.

Head. Prognathous, antennae more than 2× longer than head. Color light brown with dark brown markings between ocelli and antennae as in Fig. 3A.

Figure 3. 

Fasciamirus petersorum sp. nov., larva: A habitus dorsal B habitus lateral C habitus ventral D, E foreleg F–J abdomen.

Mouthparts. Labrum and clypeus shape as in Fig. 4A. Labrum twice wider than long; clypeus of similar proportions or slightly narrower. Dorsal surface of labrum with scattered hair-like setae and two irregular rows of bristle-like setae along anterior margin (Fig. 4A, left half; setae marked with black dots). Anterior margin deeply cleft medially with 2 large denticles, sometimes reduced or absent (Fig. 4A). Ventral surface with long hair-like setae submedially and anterolaterally (Fig. 4A, right half; setae marked with black dots). Hypopharynx shape as in Fig. 6A. Lingua with well-developed lateral processes and anterior margin deeply cleft. Superlingua extended laterally with bristle-like setae along dorsal margin, lateral margins rounded (Fig. 6A). Both mandibles with two incisor groups, separated from base and equipped with denticles (Fig. 4B, C). Prostheca of right and left mandible similar, divided into two branches, one comb-like, second with long filaments apically (Fig. 4B, C). Maxillae shape and setation as on Fig. 6B. Maxillary palps three-segmented, first and second segment of approximately same length, length of third segment 0.61–0.72 of second segment. Third segment triangular, broad at base. Shape of glossae and paraglossae as in Fig. 4D. Labial palps three-segmented, first and second segment of approximately same length, length of third segment 0.35–0.41 of second segment. Third segment triangular, broad at base with spine-like setae on inner and dorsal margins (Fig. 4D, left half).

Figure 4. 

Fasciamirus petersorum sp. nov., larva: A labrum (left half dorsal, right half ventral), clypeus, and variability of anterior margin of labrum B incisors and prostheca of left mandible C incisors and prosteca of right mandible D labium (left half dorsal, right half ventral) E foreleg F tarsal claw of foreleg G abdomen in lateral view (segments V–X) H abdomen in ventral view (segments V–IX I gill I J gill IV.

Thorax. Light brown with dark brown markings dorsally. Ganglia darkened. (Fig. 3A–C).

Legs. Femora with dark brown macula near apex and base as in Fig. 3D, E. Tibiae and tarsi yellowish brown. Maximum width of tibiae 1.62–2.00× maximum width of tarsi. Tibiae oval in cross-section. Inner margins of femora indented in apical half. Claws with denticles apically progressively larger (Fig. 4F).

Abdomen. Terga dark brown with pale markings as in Fig. 3F–J. Shape of pale markings vary from triangular (Fig. 3G–I) to longitudinal stripe with pair of lateral spots (Fig. 3F, J). Markings most expressed on terga II–VI. Sterna I–IX with medio-lateral brown maculae (Fig. 3C) and darkened ganglia. Posterolateral spines on abdominal segments (V)VI–IX (Fig. 4G, H). Spine on segment IX apically indented. Sternum IX widely rounded posteriorly (Fig. 4H).

Gills. On abdominal segments I–VII. Shape of all gills alike, lanceolate, elongated, and smoothly tapered to apex (Fig. 4I, J). All gills divided from near base. Lamellae grey, tracheae blackish.

Caudal filaments. Yellowish brown, terminal filament little longer that cerci. Length of cerci approximately 1.4× body length.

Unknown.

The species is named in honour of Janice G. Peters and William L. Peters, who discovered and described an amazing variety of New Caledonian mayflies. Plural.

The larva of the genus Fasciamirus was defined by Peters et al. (1990) based on the following morphological characters: i) inner margin of third segment of labial palps has thick heavy spines; ii) glossae of labium are straight; iii) maximum width of tibiae is 2 times maximum width of tarsi; (iv) abdominal gills I differ from gills II–VII; gill I is long, slender, usually without fork while gills II–VII are forked and each portion is long and smoothly tapered to apex; distance from base to fork of gills II–V exceeds length of ensuing segment; and (v) denticles on claws are progressively larger apically, except the apical denticle is a little larger. Fasciamirus is also characterized by specific coloration pattern of femora in larval stages and adults consisting of dark brown macula near apex and base (Peters et al. 1990: fig. 119).

It should be noted that the genus Fasciamirus was described based only on a single species, F. rae Peters, Peters & Edmunds, 1990. Therefore, larger variability in some characters can be expected when other congeneric species are described. The new species F. petersorum sp. nov. possesses most of the morphological characters of the genus as defined by Peters at al. (1990). The exception are gills that are all alike and divided near the base. We have also found variability in the width of tibiae in respect to the width of tarsi. While Peters at al. (1990) defined the width of tibiae as 2× width of tarsi, we found that the width of tibiae varies between 1.62–2.00× maximum width of tarsi. Despite these incongruences, most generic characters defining Fasciamirus are shared in F. petersorum sp. nov. Therefore, we are confident that the new species belongs to the genus Fasciamirus and the differences from F. rae represent intrageneric variability.

Finally, the attribution of the new species to the genus Fasciamirus is based on the synthesis of larval morphological characters given by Peters et al. (1990) and the identification key to the genera of New Caledonian Leptophlebiidae by Mary (2017) as follows: i) femora with distinct coloration pattern consisting of dark brown maculae near the apex and base (Fig. 3D, E); ii) gills lanceolate, narrow (width of both branches less than 1/3 of the length), elongated and gently tapering to the apex (Fig. 4I, J); iii) third segment of labial palps broad, triangular, with spine-like setae on inner margins (Fig. 4D); iv) glossae of labium are straight (Fig. 4D); and v) denticles on claws are progressively larger apically, except the apical denticle is a little larger (Fig. 4F). Additionally, we add the narrow triangular shape of the third segment of maxillary palps (Peters et al. 1990: fig. 104; Fig. 6B) among generic diagnostic characters of Fasciamirus.

Fasciamirus petersorum sp. nov. can be distinguished by a combination of the following characters: i) length of the third segment of labial palps reaching 0.35–0.41 times that of the second segment (Fig. 4D,); ii) gills on abdominal segments I–VII similar and divided from the base (Fig. 4I, J); and iii) anterior margin of labrum with two large denticles medially (sometimes reduced, Fig. 4A).

The species F. petersorum sp. nov. is the second species described in the genus Fasciamirus. It can be distinguished from F. rae by the following characters: i) gills I–VII are similar and all divided from the base (Fig. 4I, J), in contrast to F. rae, in which the first pair of gills is usually undivided, forming a single filament, and gills II–VI are divided at ¼ from the base (Peters et al. 1990: figs 121, 122); ii) the third segment of labial palps is reduced, its length reaching only to about ¼ of the second segment (Fig. 4D) [In F. rae, the third segment of labial palps reaches up to 3/5 of the second segment length and is thus only slightly shorter than the second segment (Peters et al. 1990: fig. 117)]; and iii) the anteromedian margin of labrum has two large denticles that are sometimes reduced (Fig. 4A), in contrast to F. rae with 5 (rarely 6) denticles (Peters et al. 1990: fig. 100). The reduction of denticulation on the anteromedian margin of labrum in F. petersorum sp. nov. was found in genetically similar specimens and represents intraspecific variation.

The species is distributed in the southern province of Grande Terre (Fig. 1) on ultramafic bedrock. It was found only in clear brooks flowing in pristine (or near-natural) forests, in the vicinity of Mounts Koghis near Dumbéa, Mont Mou near Païta, and Rivière Bleu. Despite low altitude (170–510 m a.s.l.), the brooks have a mountainous character and are relatively cold (19–22 °C in summer; other streams were usually 25–30 °C at that time). They included very small (less than one metre wide) or small (mean width 2–6 m) cascading brooks with prevailing turbulent flow and stony substrate (Fig. 7). However, larvae were collected in slow-flowing microhabitats with sandy and fine gravel substrate in pools.

Holotype. Female larva, New Caledonia; Chagrin, Fridoline River. (Loc. 98/2022), -20.4902778, 164.2572222, 70 m a.s.l.; 03.02.2022; leg. J. Bojková, Ľ. Hrivniak. Deposited in MZL. Paratypes. 2 larvae (1 larva mounted on slide and deposited in IECA, 1 larva deposited in MZL—DNA extracted from both), same data as holotype.

(used for DNA extraction; cuticular skin preserved and deposited in MZL). 2 larvae (GBIFCH01121825 and GBIFCH01121826), same data as holotype.

Body length of middle-instar larvae 3.0–3.5 mm. Size of late-female and male instar larvae unknown. General coloration of body yellowish with dark brown markings. Body covered by sparse hair-like setae.

Head. Prognathous, antennae more than 2× longer than head. Coloration yellowish with dark brown markings as in Fig. 5B.

Figure 5. 

Simulacala rara sp. nov., larva: A habitus dorsal B habitus lateral C habitus ventral D labrum (left half dorsal, right half ventral) and clypeus E incisors and prostheca of left mandible F incisors and prostheca of right mandible G labium (left half dorsal, right half ventral) H foreleg I tarsal claw of foreleg J abdomen in ventral view (segments V–IX) K abdomen in lateral view (segments V–X) L gill V M gill I.

Mouthparts. Shape of labrum and clypeus as in Fig. 5D. Labrum ca. 2.3× wider than long. Length and width of labrum approximately same as length and width of clypeus (Fig. 5D). Dorsal surface of labrum with scattered hair-like setae and two irregular rows of bristle-like setae along anterior margin (Fig. 5D, left half; setae marked with dots). Anterior margin medially deeply cleft, with two large denticles (Fig. 5D). Ventral surface with long hair-like setae submedially and anterolaterally (Fig. 5D, right half). Lingua with well-developed lateral processes and deeply cleft anterior margin. Superlinguae laterally extended with bristle-like setae along dorsal margins, lateral margins acute (Fig. 6C). Both mandibles with two incisor groups, separated from base and equipped with denticles (Fig. 5E, F). Prostheca of right and left mandible similar, indistinctly divided into two branches, each with long filaments apically. Shape and setation of maxillae as on Fig. 6D. Maxillary palps three-segmented, first and second segment of approximately same length, length of third segment 0.73–0.80× length of second segment. Third segment triangular and broad at base. Shape of glossae and paraglossae as in Fig. 5G. Labial palps three-segmented, length of second segment 0.82–0.95× length of first segment, length of third segment 0.61–0.68× length of second segment. Third segment triangular, broad at base, with spine-like setae on inner and dorsal margins (Fig. 5G).

Figure 6. 

A hypopharynx of Fasciamirus petersorum sp. nov. B maxilla of F. petersorum sp. nov. C hypopharynx of Simulacala rara sp. nov. D maxilla of S. rara sp. nov.

Thorax. Yellowish with dark brown markings dorsally (Fig. 5A–C).

Legs. Yellowish, without apparent pattern (Fig. 5B, H). Maximum width of tibiae 1.41–1.60× width of tarsi. Tibiae oval in cross-section. Inner margins of femora indented in apical half. Claws with 3–5 large denticles (apically progressively longer); apical part of claws hooked with a row of small denticles as in Fig. 5I.

Abdomen. Terga brownish with pale markings forming median stripe and pair of medio-lateral elongated maculae (Fig. 5A). Terga darkened sub-laterally. Sterna yellowish, without pattern (Fig. 5C). Postero-lateral spines on abdominal segments VI–IX (Fig. 5J, K). Spines on segment IX apically indented (Fig. 5K). Posterior portion of sternum IX triangular, rounded apically (Fig. 5J).

Gills. On abdominal segments I–VII. Shape of all gills alike; all gills divided from near base. Each branch narrow and distinctly elongated (e.g. gill IV in middle-instar larvae reaches or exceeds end of abdomen), smoothly tapered to apex (Fig. 5A, L, M). Lamellae pale grey, tracheae greyish.

Caudal filaments. Yellowish, terminal filament little longer than cerci. Cerci length approximately 1.2× body length.

Unknown.

The species is named according to its rare occurrence in Grande Terre. Feminine.

The larva of the genus Simulacala was defined by Peters et al. (1990) based on the following morphological characters: i) inner margin of third segment of labial palps has thick heavy spines; ii) glossae of labium are straight; iii) denticles on claws are progressively larger apically, except apical denticle larger to much larger; iv) third segment of the maxillary palps is 3/4 to 4/5 length of second segment; and v) abdominal gills I–VII are deeply forked and 2 portions of lamellae overlap; each portion is long and smoothly to abruptly tapered to apex. Mary (2017) added two additional characters for the identification of the genus: i) anterior margin of labrum with 2 or 3 large denticles and ii) length of the distal segment of the labial palp approximately equal to its maximum width.

Almost all generic characters mentioned above correspond to S. rara sp. nov. suggesting its position in the genus Simulacala. The only exception is the length of the distal segment of the labial palps, reaching approximately 1.5 times its width. Nevertheless, other characteristics of labial palps, notably the presence of dense spines on the inner and dorsal margins correspond to the genus Simulacala.

The genus Fasciamirus is most closely related to Simulacala and their larvae possess similar morphological characters as indicated by Peters et al. (1990). They can be distinguished based on the presence of dark bands on femora of all legs in Fasciamirus, whereas these bands are absent in Simulacala; this applies to imagos, subimagos and larvae (Peters et al. 1990). According to our observation, this coloration pattern is visible already in younger larval instars of Fasciamirus. Femora of S. rara sp. nov. do not exhibit dark bands, suggesting an attribution to the genus Simulacala. Additionally, longer and wider triangular shape of the third segment of maxilary palp in S. rara sp. nov. is characteristic for the genus Simulacala (see Peters et al. 1990: fig. 110 and Fig. 6D). Fasciamirus possesses a rather narrower triangular and a shorter third segment of maxilary palps (see Peters et al. 1990: fig. 104 and Fig. 6B).

According to the larval morphological characters given by Peters et al. (1990) and Mary (2017), S. rara sp. nov. is attributable to the genus Simulacala based on following characters: i) third segment of labial palps broad, triangular, with spine-like setae on inner margins (Fig. 5G); ii) gills lanceolate, narrow (width of both branches less than 1/3 of length) and divided at base (Fig. 5L, M); iii) tibiae of all legs oval in cross-section; iv) denticles on claws are progressively larger apically with apical denticle larger to much larger (Fig. 5I); v) glossae of labium are straight (Fig. 5G); vi) segment 3 of the maxillary palps is 3/4 to 4/5 length of segment 2 (Fig. 6D); vii) femora of all legs without dark apical and distal maculae (Fig. 5B).

We do not rule out the possibility that S. rara sp. nov. may represent a separate monospecific genus, as the larval morphological convergences in New Caledonia are extreme and adults, bearing more informative systematic traits, are unknown. Nevertheless, the larvae of S. rara sp. nov. are morphologically most similar to the genus Simulacala as currently defined. Therefore, we describe this species therein until the large-scale revision of New Caledonian Atalophlebiinae is completed, based on larger number of mitochondrial and nuclear markers. This revision is currently in preparation.

Simulacala rara sp. nov. can be distinguished by the combination of the following characters: i) all gills narrow, smoothly tapering to the apex, distinctly elongated and reaching or exceeding end of abdomen in middle-instar larvae (Fig. 5A, L, M); ii) femora and mesobasisternum without dark markings (Fig. 5B, H); iii) anteromedian margin of labrum with two large denticles (Fig. 5D).

Three other species of the genus Simulacala occur in Grande Terre: Simulacala notialis Peters, Peters & Edmunds, 1990, S. massula Peters, Peters & Edmunds, 1990, and S. milleti Peters, Peters & Edmunds, 1990. Simulacala rara sp. nov. can be distinguished from all known species by distinctly elongated and narrow gills (Fig. 5A, L, M). Simulacala notialis is characterised by shorter (gill IV reaches tergum VII) and wider gills that taper abruptly toward the apex (Peters et al. 1990: fig. 131). Simulacala massula and S. milleti have gills that taper gently toward the apex, but are distinctly shorter (gill IV in middle-instar larvae reaches tergum VII–IX) and that are wider (Peters et al. 1990: figs 132, 135, respectively) than in S. rara sp. nov. with narrow gills and gill IV reaching or exceeding end of abdomen in middle-instar larvae. Simulacala massula can be distinguished by a blackish macula on the anterior margin of the mesobasisternum and apically darkened femora (Peters et al. 1990: fig. 133) from S. rara sp. nov. and S. milleti with femora and thoracic sterna without any pattern.

The species was found in the single stream Fridoline (a small stream, 3–5 m wide) in the northern province of Grande Terre (Fig. 1), on ultramafic bedrock. Its catchment includes the area of old chromite mines and active nickel laterite mines. We did not find elevated concentrations of dissolved metals (Fe, Mn, Cr, Ni) in the stream water, but magnesium content was very high (66.7 mgl^-1) and bed surface was rich in iron precipitates. The stream was eutrophic, with total P concentration 26.2 µgl^-1 and about 70% cover of bed substrate by filamentous green algae. The sampled section had riffles with slightly turbulent flow and gravel substrate, and predominant slow-flowing part with sandy and fine gravel substrate (Fig. 7D, E). Larvae were collected from fine gravel and sand behind stones in the riffles. They avoided similar fine-grained sediments in the slow-flowing part of the section.

Figure 7. 

A type locality of Fasciamirus petersorum sp. nov. B, C variability in habitat of F. petersorum sp. nov. D, E type locality of Simulacala rara sp. nov.