Fasciamirus petersorum Hrivniak & Bojkova, 2023

Hrivniak, Ľubos, Sartori, Michel, Sroka, Pavel & Bojkova, Jindriska, 2023, Big diversity in a small hotspot: two new species of Leptophlebiidae (Insecta, Ephemeroptera) from New Caledonia, ZooKeys 1143, pp. 71-88 : 71

publication ID	https://dx.doi.org/10.3897/zookeys.1143.96148
publication LSID	lsid:zoobank.org:pub:6550FE87-6B87-411C-8259-56068C03CC59
persistent identifier	https://treatment.plazi.org/id/F1FC1C40-C49C-45CC-BF8D-E7C9CE961991
taxon LSID	lsid:zoobank.org:act:F1FC1C40-C49C-45CC-BF8D-E7C9CE961991
treatment provided by	ZooKeys by Pensoft
scientific name	Fasciamirus petersorum Hrivniak & Bojkova
status	sp. nov.

Treatment

Fasciamirus petersorum Hrivniak & Bojkova sp. nov.

Material examined.

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 GoogleMaps . Paratypes. 33 larvae, same data as holotype. Deposited in MZL GoogleMaps . 12 larvae, New Caledonia; left tributary of Riviere 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) GoogleMaps . 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) GoogleMaps . 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 GoogleMaps . 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 GoogleMaps .

Description of larva.

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 View Figure 3 .

Mouthparts. Labrum and clypeus shape as in Fig. 4A View Figure 4 . 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 View Figure 4 , left half; setae marked with black dots). Anterior margin deeply cleft medially with 2 large denticles, sometimes reduced or absent (Fig. 4A View Figure 4 ). Ventral surface with long hair-like setae submedially and anterolaterally (Fig. 4A View Figure 4 , right half; setae marked with black dots). Hypopharynx shape as in Fig. 6A View Figure 6 . 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 View Figure 6 ). Both mandibles with two incisor groups, separated from base and equipped with denticles (Fig. 4B, C View Figure 4 ). Prostheca of right and left mandible similar, divided into two branches, one comb-like, second with long filaments apically (Fig. 4B, C View Figure 4 ). Maxillae shape and setation as on Fig. 6B View Figure 6 . 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 View Figure 4 . 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 View Figure 4 , left half).

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

Legs. Femora with dark brown macula near apex and base as in Fig. 3D, E View Figure 3 . 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 View Figure 4 ).

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

Gills. On abdominal segments I-VII. Shape of all gills alike, lanceolate, elongated, and smoothly tapered to apex (Fig. 4I, J View Figure 4 ). 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.

Subimago, imago, and egg.

Unknown.

Etymology.

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.

Generic attribution.

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 View Figure 3 ); 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 View Figure 4 ); iii) third segment of labial palps broad, triangular, with spine-like setae on inner margins (Fig. 4D View Figure 4 ); iv) glossae of labium are straight (Fig. 4D View Figure 4 ); and v) denticles on claws are progressively larger apically, except the apical denticle is a little larger (Fig. 4F View Figure 4 ). Additionally, we add the narrow triangular shape of the third segment of maxillary palps ( Peters et al. 1990: fig. 104; Fig. 6B View Figure 6 ) among generic diagnostic characters of Fasciamirus .

Larval morphological diagnostics.

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 View Figure 4 ,); ii) gills on abdominal segments I-VII similar and divided from the base (Fig. 4I, J View Figure 4 ); and iii) anterior margin of labrum with two large denticles medially (sometimes reduced, Fig. 4A View Figure 4 ).

Differential diagnosis.

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 View Figure 4 ), 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 View Figure 4 ) [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 View Figure 4 ), 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.

Distribution and habitat preferences.

The species is distributed in the southern province of Grande Terre (Fig. 1 View Figure 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 View Figure 7 ). However, larvae were collected in slow-flowing microhabitats with sandy and fine gravel substrate in pools.