Dudgeodes molinerii Sivaruban, Martynov, Srinivasan, Barathy & Isack, 2022

Martynov, Alexander V., Sivaruban, T., Palatov, Dmitry M., Srinivasan, Pandiarajan, Barathy, S., Isack, Rajasekaran & Sartori, Michel, 2022, Contribution to the knowledge of Teloganodidae (Ephemeroptera, Ephemerelloidea) of India, ZooKeys 1113, pp. 167-197 : 167

Dudgeodes molinerii Sivaruban, Martynov, Srinivasan, Barathy & Isack sp. nov.

Figs 9 , 10 , 11

Material examined.

Holotype: mature ♀ larva, India, Tamil Nadu, Theni district, Kurangani hills, Kottakudi River , 10.0809°N, 77.2552°E, 632 m a.s.l., 28.x.2020, Pandiarajan Srinivasan & Isack Rajasekaran leg., ZSI-SRC/I/E/654 . Paratypes: 5 larvae, ibid., 28.x.2020, Pandiarajan Srinivasan & Isack Rajasekaran leg., ZSI-SRC/I/E/655 (1 larva), AMC ZN 237 (4 larvae) .

Etymology.

The new species is named in honour of Dr Carlos Molineri of Argentina, who contributed significantly to the study of mayflies.

Description.

Mature larva. Body length 4.7-4.9 mm; cerci length subequal to body length. General coloration of the dorsal side of head dirty yellow, with dark brown to blackish maculations; thorax and abdomen dark brown to blackish, with dirty yellow maculations (Fig. 9A-D ). Ventral side of body yellowish to light brown. Dorsal surface of femora with two blackish longitudinal stripes one medial along ridge and one along outer margin; also three (proximal, medial, and distal) black spots with indistinct borders along medial ridge; proximal and medial spots divided in two parts by brownish bands (Fig. 11A-C ). Dorsal part of male eyes dark brown to black (Fig. 9D ). Abdominal terga I-VIII with pair of submedian yellowish spots. Anterior part of tergum X yellowish (Fig. 9C ).

Head with pair of occipital tubercles (Fig. 9D ). Genae moderately developed. Lateral margin of head capsule from eye to labrum insertion with row of long, forked near the base, stout setae with pointed apices (Fig. 9E ). Antennae length 1.25 times head width, flagellum with 11 segments. Head covered with scattered short hair-like setae and short stout setae with slightly divergent margins.

Mouthparts. Labrum compact, width/length ratio 2.51-2.53; with smooth anterior emargination; dorsal surface with transversal row of scattered, stout, hair-like setae (Fig. 10C, D ); anterior area and margin of labrum densely covered with differently sized feathered setae. Mandibles slender with long, stout, hair-like seta in the middle of the outer margin (Fig. 10A, B ). Number of teeth of both mandibular outer incisors cannot be determined precisely due to their wear in type specimens. Right mandible inner incisor with two teeth; prostheca reduced, with the appearance of a cluster of thin setae; small row of five long, stout, hair-like setae below mola and some short setae above mola. Left mandible inner incisor with two teeth inserted transversely, one smaller and rounded and other one larger and rounded; prostheca small; no setae below and above mola. Maxilla (Fig. 10F, G ) slender, shape of canine impossible to determine (completely worn); two indented dentisetae and three long setae on inner apical part and cluster of long, simple setae at crown; inner margin at the base of lacinia, with two feathered, long setae; maxillary palp highly reduced to protuberance. Hypopharynx (Fig. 10E, H ) with long, feathered setae on the rounded apexes of superlinguae and very short setae on lingua. Labial palp (Fig. 10I, J ) three-segmented, slightly constricted towards apex; articulation between segments clearly visible; segment III elongate and rounded apically, length/width ratio at base 2.0-2.1. Surface and margins of segments I and II covered with scattered long, stout, hair-like setae; segment III bare. Submentum well developed laterally. Glossae and paraglossae short and broad, rounded apically, their apexes densely covered with differently sized, feathered, stout setae; outer margins of paraglossae covered with long feathered setae.

Thorax. Pronotum with three pairs of tubercles: SMs, SLs, and Ls; tubercles with a few short, rounded setae. Mesonotum with three pairs of tubercles: two pairs of SMMs, a pair of LAs, and unpaired MP (Fig. 9C, F ).

Forefemur broad, ca 1.3 times longer than wide (Fig. 11A, D ); outer margin covered with a row of long, stout, hair-like setae (Fig. 11G ); submarginal row of setae composed of scattered, short, stout setae with rounded apices; basal half of inner margin with row of long, stout, hair-like setae; distal half almost without setae. Transverse row on the dorsal surface made of about 30 long, pointed apically stout setae (Fig. 11E, F ). Dorsal surface of fore femur covered with scattered, short, stout setae and thin, hair-like setae. Dorsal surface of fore tibia with solitary hair-like setae and oblique regular row of long, stout, hair-like setae; outer margins of tibia with regular row of long, stout, hair-like setae.

Middle and hind femora, in contrast to fore femur, more slender, ca 1.8-2 times longer than wide, with denser submarginal row of short, stout setae (Fig. 11B, C ). Outer and inner margins covered with a regular row of long, stout, hair-like setae. Outer margin of middle and hind tibiae with a regular row of long, stout, hair-like setae. Setation of dorsal surface of middle and hind tibiae similar to those of fore leg.

Tarsal claw moderately hooked, bearing 3-6 medial denticles, 1-2 subapical denticles (if two subapical denticles present, they are situated each on opposite sides of claw) and a row of 3-4 subapical setae on dorsal and ventral sides (Fig. 9G ).

Abdomen. All terga with median tubercles that bear short, stout setae with slightly divergent margins. Median tubercles moderately developed on terga IV-VIII, and slightly marked on terga I-III, IX, and X (Fig. 11H ). Posterolateral projections moderately developed on segments VI-IX, and slightly marked on segments II-V. Submedian and sublateral areas of terga VI and VII with scattered stout setae with divided apices and a few small, rounded stout setae.

Gills on segments II-V (Fig. 9H-K ); gill II with dorsal lamella operculate, oval and with entire margin; gills III-V with dorsal lamella incised medially.

Cerci length subequal to the body length; posterior margin of proximal half segments with elongate, stout setae with rounded apices; posterior margin of distal half segments with long, spine-like setae on the lateral margins; length of the stout setae less than length of corresponding segment. Paracercus absent.

Egg. Ovoid, ca 100-110 μm long, with numerous micropyles. Egg with one polar cap, on the opposite pole with a cluster of 18-20 spines (Fig. 11I-K ).

Winged stages. Unknown.

Distribution.

Western Ghats (Tamil Nadu, India).

Habitats.

The larvae of D. molinerii sp. nov. inhabit cobble and pebble substrates of rivers with a strong current (Fig. 16E ), where there is no significant anthropogenic stress. Water temperatures range between 20 and 22 °C and pH ranges between 7.1 and 7.4. This species was caught with other mayflies such as Clypeocaenis malzacheri Srinivasan, Sivaruban, Barathy & Isack, 2022 ( Caenidae ), Nigrobaetis klugei Sivaruban, Srinivasan, Barathy & Isack, 2022 ( Baetidae ), Notophlebia sp. ( Leptophlebiidae ), and Tenuibaetis frequentus ( Müller-Liebenau & Hubbard, 1985) ( Baetidae ).

Diagnosis.

Dudgeodes molinerii sp. nov. can be distinguished from other Dudgeodes species by the following combination of characters. Larva: (i) dorsal part of male eyes dark brown to black; (ii) head with pair of small occipital tubercles; (iii) antennae length 1.25 times head width, flagellum with 11 segments; (iv) labrum with transversal row of scattered, stout, hair-like setae; (v) forefemur with transverse row of about 30 long, apically pointed, stout setae; (vi) tarsal claw bearing 3-6 medial denticles, and 1-2 subapical denticles (if two, they are on opposite sides of claw), and 3-4 subapical setae on dorsal and ventral sides; (vii) pronotum bears three pairs of tubercles: SMs, SLs, and Ls; mesonotum bears three pairs of tubercles: two pairs of SMMs, a pair of LAs, and unpaired MP; (viii) median tubercles moderately developed on terga IV-VIII, and slightly marked on terga I-III, IX and X; (ix) posterolateral projections moderately developed on segments VI-IX, and slightly marked on segments II-V. Egg: (i) egg with cluster of 18-20 spines present on pole opposite to polar cap; (ii) surface without microgranules.

Larval stage of this new species can be easily distinguished from other Indian Dudgeodes by: (i) presence of tubercles on head; (ii) number of tubercles on pro- and mesonotum; (iii) shape of femora; (iv) setation of forefemur; (v) size and shape median tubercles on abdomen.

Figures

Figure 9. Larva of Dudgeodes molinerii Sivaruban, Martynov, Srinivasan, Barathy, Isack, sp. nov., paratypes A total dorsal view B total ventral view C head, thorax and abdomen, dorsal view D head, dorsal view E row of setae at outer margin of head F head and thorax, dorso-lateral view G tarsal claw H gill II I gill III J gill IV K gill V. Abbreviations: white arrows show tubercles.

Figure 10. Larva of Dudgeodes molinerii Sivaruban, Martynov, Srinivasan, Barathy & Isack, sp. nov., paratypes A, B mandibles C labrum D stout setae of transversal row of labrum E hypopharynx F maxilla G apical part of maxilla H superlingua I labium J labial palp.

Figure 11. Larva of Dudgeodes molinerii Sivaruban, Martynov, Srinivasan, Barathy & Isack, sp. nov., paratypes A, D fore femur B middle femur C hind femur E, F stout setae of transversal row on forefemur G outer margin of fore femur H abdomen I eggs, light microscopy J egg, SEM microscopy K cluster of spines on pole of egg. Abbreviations: sII - abdominal segment II, sX - abdominal segment X. Scale bars: 0.2 mm (H); 0.02 mm (J); 0.01 mm (K).

Figure 16. Type habitats A, B, D, E of new species and cages (Martynov's construction) C used for Dudgeodes selvakumari Martynov & Palatov, sp. nov. winged stages rearing A, B, D type habitat of Dudgeodes selvakumari Martynov & Palatov, sp. nov. C Martynov-designed grow nets for mayfly winged stages rearing E type habitat of Dudgeodes molinerii Sivaruban, Martynov, Srinivasan, Barathy & Isack, sp. nov. and Teloganodes barathyae Sivaruban, Martynov, Srinivasan & Isack, sp. nov. Abbreviations: arrows show microhabitats with the highest density of a new species' larvae.