Nigrobaetis klugei Sivaruban & Srinivasan & Barathy & Isack 2022, sp. nov.
Creators: name: Sivaruban, T.
name: Srinivasan, Pandiarajan
name: Barathy, S.
name: Isack, Rajasekaran
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Ephemeroptera
Baetidae
Nigrobaetis
Nigrobaetis klugei

description: Nigrobaetis klugei sp. nov.
(Figs 1–3)
Materials Examined. Holotype (in alcohol): Female mature nymph (Reg. No. ZSI –SRC/I/E/611), South India, Tamil Nadu, Rajapalayam district, Sastha falls, 9°41’50’’N & 77°40’15’’E; 195 m a.s.l; 24/I/2021, Pandiarajan Srinivasan & Rajasekaran Isack. Paratypes (in alcohol): 1 male nymph (Reg. No. ZSI –SRC/I/E/612), 2 male nymphs (AMC ZN 203) and 9 female nymphs (AMC ZN 204) same data as holotype.
Mature nymph (in alcohol): Length: Body 3.2–3.5 mm; cerci 1.1–1.3 mm (Fig. 1A); terminal filament shorter in female (0.7–0.8 mm) than in male (0.9–1.0 mm).
Coloration: Head uniformly brown without vermiform marks on vertex and frons. Eyes of male nymphs reddish brown, thorax dark brownish without any pattern. Legs generally whitish, dorsal side of femora with a brown band at 2/3 distally and dark brown apically (Figs 3B & 3C). Abdominal tergite I light brownish, tergites II and III dark brownish, tergite IV light brownish, tergites V-VII dark brownish, tergite VIII light brownish; tergite IX whitish; tergite X dark brownish without any spots (coloration paler in younger specimens) (Figs 1B& 1C). Entire surface of tergites covered with scales. Abdominal sternites I to V light brown; sternites VI and VII dark brownish; sternites VIII and IX paler. Cerci dark brownish in proximal part and paler in the distal part.
Head: Antennae close to each other (Fig. 1D). Labrum: dorsal surface (Fig. 2A) with 1+3 long simple stout setae on the distal half and 6-7 small simple setae scattered on the surface; ventral surface with three to four small pointed setae near lateral margin; distal margin with two kinds of setae: laterally 7 to 8 long, feathered setae and medially shorter, slightly feathered setae. Hypopharynx: lingua trilobed, covered with small simple setae; superlinguae with thin setae apically and laterally (Fig. 2B). Incisors of left mandible (Fig. 2C) with 6 denticles; prostheca with 7 broad denticles and a reduced comb-shaped structure; margin between prostheca and mola proximally with 2 large spines and distally with 5 minute spines; tuft of setae at apex of mola absent. Incisors of right mandible (Fig. 2D) with 8 denticles; prostheca with 7 denticles; margin between prostheca and mola with 11-12 medium pointed spines; tuft of setae at apex of mola present. Maxillae (Fig. 2E) with 3 broad canines; absence of setae at base of canines, 3 setae at base of lacinia; palp two-segmented; segment I approximately 1.1 x length of segment II; segment II apically rounded, covered with thin setae. Labium (Fig. 2F): Glossae slightly shorter than paraglossae; inner margin of glossae with a row of 10–11 setae; paraglossae as wide as glossae (Fig. 2G), falcate, with long and stout setae on outer margin and dorsally 4 long simple setae near inner margin; labial palp three-segmented, segment I subrectangular and subequal in lengths to segment II and III combined; simple small setae on the lateral margin of segment I; segment II with a dorsal oblique row of three long pointed setae; segment III truncated and apically rounded with medium to small pointed setae.
Thorax: Foreleg (Fig. 3A). Femora. Villopore absent, outer margin of femora with about 11 stout, apically rounded setae with minute hairs (Fig. 3B); inner margin with 13-14 small stout setae which are variable in size. Tibiae. Outer margin with 11 small simple setae; inner margin with 9-10 spines, with a single large comb-shaped, unipinnate seta and a bipinnate seta present on its apex (Fig. 3A). Tarsi. Outer margin with ca. 8 small stout setae; inner margin with 8-9 spines. Tarsal claws (Fig. 3F) hooked with one row of about 11 acute teeth increasing in size towards apex. Midleg (Fig. 3D). Outer margin of femora with about 8 stout, apically rounded setae and with minute hairs; inner margin with 11-12 small stout setae. Tibiae. Outer margin with 11 small simple setae present; inner margin with 9 small spines present. Tarsi. Outer margin with 7-8 small simple setae; inner margin with 5 small spines. Claws of mid and hind legs similar to that of foreleg. Hindleg (Fig. 3E). Outer margin of femora with 9 stout apically rounded setae. Tibiae. Outer margin bare; inner margin with 10 small spines. Outer margin of tarsi bare; inner margin with 5 small spines. Hindwing pads present (Fig. 3G).
Abdomen: Tergites with numerous scale bases, posterior margin with long and pointed triangular spines in segments I to X (Figs 3G–H). Gills on segments I to VII; gill I elongated and reduced (Fig. 3H); gills II to VII elliptic with dark margin, relatively long setae and serrated all along margins, tracheation well visible but poorly divided (Fig. 3I). Whorls of spines on cerci large and triangular in shape reaching 1/2 of the corresponding segment (Fig. 3J). Paraproct (Fig. 3K) with abundant scale bases, but almost no setae and reduced number of spines on distal margin (three large and two small spines); postero-lateral extension with scale bases, margin with numerous blunt, triangular, small spines.
Imago: Unknown
Diagnosis: Nigrobaetis klugei sp. nov. can be differentiated from other Oriental species of Nigrobaetis by the following combination of characters: (i) dorsal surface of the labrum with 1+3 long simple stout setae on the distal half (Fig. 2A); (ii) paraproct distally not expanded, with a reduced number of spines on distal margin (Fig. 3K); (iii) paraglossae slender, approx. as wide as glossae (Fig. 2G); (iv) absence of mediolateral spots on abdominal tergites (Fig. 1B); (v) outer margin of forefemora with 11 stout setae (Figs 3A–C); (vi) posterior margin of tergum with long and pointed triangular spines in segments I to X (Figs 3G–H).
Etymology: The new species is named after Dr. N. J. Kluge, for his outstanding contribution to mayfly systematics and phylogeny.
Ecology: The nymphs of N. klugei sp. nov. were collected in the Sastha falls (Fig. 5) of Western Ghats (5–7 m wide, 2.1–2.4 cm depth). The water temperature ranges between 26°C–28°C; pH 7.1–7.4. Substratum is mainly made of rock, cobbles and gravel.
description: Published as part of Sivaruban, T., Srinivasan, Pandiarajan, Barathy, S. & Isack, Rajasekaran, 2022, A new species of Nigrobaetis Novikova & Kluge, 1987 (Ephemeroptera, Baetidae) from Tamil Nadu, India, pp. 182-190 in Zootaxa 5091 (1) on pages 183-188, DOI: 10.11646/zootaxa.5091.1.8, http://zenodo.org/record/5840735