Teloganodes (Dudgeodes) palnius ( Selvakumar et al. 2014 )

Kluge, Nikita, Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S. & Isack, Rajasekaran, 2023, Indian species of Teloganodes Eaton 1882 (including subgenera Dudgeodes Sartori 2008 and Derlethina Sartori 2008) (Ephemeroptera, Teloganodidae), Zootaxa 5244 (6), pp. 553-587 : 573-579

Teloganodes (Dudgeodes) palnius ( Selvakumar et al. 2014)

( Figs 13–16 , 106–136 )

Dudgeodes palnius Selvakumar, Sivaramakrishnan & Jacobus in Selvakumar, Sivaramakrishnan, Jacobus, Janarthanan & Arumugam 2014: 95 (larva). Teloganodes (Dudgeodes) palnius: Kluge 2023 . Dudgeodes bharathidasani Anbalagan in Anbalagan, Balachandran, Kannan, Dinakaran & Krishnan 2015: 308 (larva), syn. n. Dudgeodes sartorii Srinivasan, Sivaruban, Barathy & Isack 2021: 572 (larva), syn. n. (non Teloganodes sartorii Selvakumar et al. in Selvakumar et al. 2014). Dudgeodes molinerii Sivaruban, Martynov, Srinivasan, Barathy & Isack in Martynov, Sivaruban, Palatov, Srinivasan, Barathy, Isack & Sartori 2022: 181 (larva), syn. n.

Material examined. INDIA: state Karnataka, border of Shivamogga and Udupi districts near Agumbe and Someswar , 30.I.2013, coll. L. Sheyko & N. Kluge: L-SJ ( ZIN) ; state Tamilnadu: Tirunelveli district, Courtallam, Chittar river near Peraruvi (= Main Falls ), 4.I–7.II.2013, coll. L. Sheyko & N. Kluge: L-S-IJ, 16 larvae ( ZIN) ; Theni district, Suruli Falls , 24–26.I.2016, coll. L. Sheyko & N. Kluge: 1 larva ( ZIN) ; Dindugal district, near Kodaikanal , 29.I–3.II.2016, coll. L. Sheyko & N. Kluge: L/SJ, L/S ♀ /O, 10 larvae ( ZIN) . State Tamilnadu, Theni District, Megamalai Hills , Manalar , 9°69.83′N, 77°40.08′E, ca. 1422 m, 22.X.2020, coll. P. Srinivasan & R. Isack: 4 larvae ( AMC ZN 188 , 189 , holotype and paratypes of D. sartorii ) . Theni District, Kurangani Hills, Kottakudi River , 10°08.09′N, 77°25.52′E, ca. 632 m, 28.X.2021, coll. P. Srinivasan & R. Isack: 4 larvae ( AMC ZN 237 , paratypes of D. molinerii ) .

Descriptions

Larva. Described by Anbalagan et al. (2015), Selvakumar et al. (2014), Srinivasan et al. (2021), Martynov et al. (2022). Additional characters: Labrum with simple setae forming transverse field all over labrum width, with feathered setae located distad of this field (as in Kluge 2023: figs 7). Abdominal terga I– V with thin setae on posterior margins; setae on tergum I larger and forming pair of rows on lateral parts of tergum; setae on terga II– V smaller; tergum VI with thin and slightly widened setae forming pair of rows on lateral parts of posterior margin ( Fig. 110 ); terga VII–IX with small, stout setae on surface and near posterior margin; posterior margins of terga VII–IX with small denticles ( Figs 111 ). Lateral sides of terga VI –VIII and anterior part of tergum IX with long setae; lateral sides of tergum IX with short, stout setae ( Fig. 111 ). Tergalii II–III with two-branched ventral lobe; tergalius IV with ventral lobe consisted of anterior branch only ( Fig. 15 ). Tergalius V stretched posteriorly, with cleft on straight outer margin; ventral lamella absent ( Fig. 16 ). Posterior margin of sternum IX evenly convex (in male with small protogonostyli by sides) ( Fig. 111 ).

Subimago. CUTICULAR COLORATION. Pronotum brown. Mesonotum with anterior scutal chromozone and latero-posterior scutal chromozones brown, achromozone contrastingly colorless ( Fig. 115 ). Thoracic pleura and sterna with light brown and colorless areas. Wings brown. Fore femur with longitudinal dark brown and colorless bands; middle and hind femora lighter with longitudinal colorless band; fore tibia darker than tarsus, darkened with brown basally; middle and hind tibiae lighter, darkened with light brownish near base ( Figs 121–122 ). Abdominal terga, sterna and cerci light brown. Male genitalia— Figs 124–125 .

HYPODERMAL COLORATION. As in imago.

Imago, male. Head brown with ochre. Dorsal eyes reddish ( Fig. 113 ). Thorax brown with membranes ochre ( Fig. 112 ). Fore wing with membrane colorless, costal and subcostal fields whitish; veins C, Sc, RA and costal brace partly colorless, partly bordered with dark brown; distal part of RSa and bullae on RSa and RSp bordered with dark brown, other longitudinal veins mostly colorless; crossveins colorless; crossveins of pterostigma simple and complete (similar to Fig. 65 ). Hind wing parallel-sided, with costal projection proximad of midlength; basal part of membrane and proximal portion of RA+MA dark brown, other membrane and veins colorless ( Figs 116–117 ). Femur of each leg with three more or less expressed purple-brown markings: on proximal half, on distal half and along outer margin ( Figs 118–120 ). On foreleg, femur mostly purple-brown, basally ochre; tibia mostly ochre, with dark brown base and apex; tarsus mostly ochre, with dark brown apex ( Fig. 118 ). On middle and hind legs, femur mostly ochre with contrasting purple-brown markings and extreme apex dark brown; tibia mostly ochre, with dark brown base; tarsus mostly ochre, with dark brown apex ( Figs 119–120 ). Abdominal terga mostly purple-brown, with darker brown, lighter ochre and grayish maculae; paired ochre maculae largest on tergum VI ( Fig. 114 ). Abdominal sterna ochre, with indistinctly expressed lighter sigilla. Styliger light ochre-brownish, gonostyli and penis ochre. Gonostyli slender ( Fig. 123 ). Penis longer than 1st segment of gonostylus, slender and nearly parallel-sided ( Figs 123, 127 ), with apices pressed together and common unpaired gonopore exposed dorsally ( Fig. 126 ).

Imago, female (as revealed by mature larva ready to molt to subimago). On foreleg, femur mostly ochre with two diffusive reddish markings and extreme apex dark brown; tibia mostly ochre, tarsus mostly ochre, with dark brown apex. Middle and hind legs as in male.

Egg ( Figs 130–136 ; Martynov et al. 2022: figs 11 I–K). Oval. Area opposite to polar cap, with slender, pointed processes directed toward cap-free pole and party projected behind it. Other surface without scales or polygonal plates. Polar cap easily falling off. Surface of polar cap surrounded by up to 13 roundish tubercles formed by tops of threads, as well as other cap surface.

Comparison. Larva of T. (D.) palnius well differs from other species of Dudgeodes by reduction of the posterior branch of the ventral lobe of tergalius IV ( Fig. 15 ; Selvakumar et al. 2014: fig. 76; Martynov et al. 2022: fig. 9J).

Comments. Both in the original descriptions of D. palnius and D. molinerii , the dorsal parts of male eyes are said to be ́blackish» ( Selvakumar et al. 2014) or ́dark brown to black» ( Martynov et al. 2022), while actually they are reddish, as in male imago ( Fig. 113 ). In the second case, a female larva was taken for male larva ( Martynov et al. 2022: fig. 9D).

Synonymy of T. (D.) bharathidasani . The original description of D. bharathidasani did not contain comparison with the earlier described species D. palnius ; judging by the list of references, its authors were aware of the publication where D. palnius was described ( Anbalagan et al. 2015). Judging by the original description, it is identical to T. (D.) palnius .

Synonymy of T. (D.) sartorii . According to the original description ( Srinivasan et al. 2021), D. sartorii differs from the previously described Indian species of Dudgeodes (i.e., D. palnius and D. bharathidasani ) by the following characters: ́(i) Prothorax with two rounded tubercles».Actually, head, pronotum and mesonotum of all Teloganodes have uneven surface, which can be interpreted as bearing this or that number of tubercles ( Fig. 106 ). ́(ii) Outer margin of mesothorax bears simple setae». Actually, both bifurcate and simple setae can be found on margins of mesonotum in all species of Teloganodes . ́(iii) Distinct maculae in the distal region of femora; (iv) transverse row of setae on fore femora narrower with blunt apex and (v) dark brownish band on the 5th segment of cerci». Actually, these three features are figured in the original description of D. palnius ( Selvakumar et al. 2014: figs 66–70, 72).

According to the classification accepted here, two species originally described in different genera, Teloganodes sartorii Selvakumar et al. in Selvakumar et al. 2014 and Dudgeodes sartorii Srinivasan et al. 2021 appear in one and the same genus Teloganodes and because of this become secondary homonyms. According to the International Code of Zoological Nomenclature ́A species-group name while a junior secondary homonym must be treated as invalid by anyone who considers that the two species-group taxa in question are congeneric» (Article 59.1). In the given case, we consider both secondary synonyms invalid because of subjective synonymy.

Synonymy of T. (D.) molinerii . According to the original description ( Martynov et al. 2022), D. molinerii differs from other Indian Dudgeodes by presence of a pair of tubercles on head, three pairs of tubercles on pronotum and three pairs of tubercles on mesonotum, while in the original description of D. palnius , no tubercles on head and four rounded tubercles on pronotum and mesonotum were reported. Actually, head, pronotum and mesonotum of all Teloganodes have uneven surface, which can be interpreted as bearing this or that number of tubercles ( Fig. 106 ). According to the original description of D. palnius , it has ́no posterolateral projections on segments II–IV, but distinct on segments V–IX», while according to the photo ( Selvakumar et al. 2014: fig. 73) the posterolateral projections are present on segments VI–IX, but not on the segment V; the same is reported in the original description of D. molinerii . In this species, median tubercles are larger on the middle abdominal terga and smaller on the anterior and posterior ones, that is reported for D. palnius as «moderately developed ... on segments I and X, more highly developed on segments II–IX» ( Selvakumar et al. 2014: 99), and for D. molinerii as ́moderately developed on terga IV–VIII, and slightly marked on terga I–III, IX and X ( Martynov et al. 2022: 185)». Other larval characters reported as distinguishing D. molinerii from other Dudgeodes , also do not contradict the original diagnosis of D. palnius ; they are: ́antennae length 1.25 times head width, flagellum with 11 segments» (actually, number of flagellomeres varies individually in all mayfly larvae); ́labrum with transversal row of scattered, stout, hair-like setae» (the same in all other Teloganodes ); ́forefemur with transverse row of about 30 long, apically pointed, stout setae» and ́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». Thus, T. (D.) molinerii , which was originally described as larvae and eggs, has no difference from T. (D.) palnius , which was originally described as larvae only.

Comment: larval setation. Setation of dorsal surface of labrum is correctly described by Martynov et al. (2022): ́dorsal surface with transversal row of scattered, stout, hair-like setae; anterior area and margin of labrum densely covered with differently sized feathered setae». Selvakumar et al. (2014) and Srinivasan et al. (2021) incorrectly wrote that ́dorsal face covered medially by scattered simple long setae; anterior margin with row of small thin setae», while this species has both simple and feathered setae. Anbalagan et al. (2015) wrongly took dirt on the simple setae for ́feather structure».

Comment: male genitalia in larval stage. As in other examined species of Teloganodes , larval protopenis is short, independently from size and shape of the imaginal penis; developing subimaginal penis is located under the larval cuticle in such a method, that its small apical portion is located inside the cuticle of larval protopenis, and remainder part of penis is spread, located proximad of the protopenis and is sharply wider than the protopenis; this gives the developing penis a peculiar shape different from the shape of imaginal penis ( Figs 128–129 ; compare with Figs 126–127 ). Because of this, structure of larval genitalia does not help to associate larvae and male imagines.

Figures

FIGURES 1–19. Tergalii of Teloganodes with ventral lobe turned out. 1–6, tergalii II–VI of T. (Teloganodes) velutinus sp. n. (5 and 6, tergalii VI of the same individual); 7–12, tergalii II–VI of T. (T.) dentatus (11 and 12, tergalii VII of different individuals); 13–16, tergalii II–V of T. (Dudgeodes) palnius; 17–19, tergalii II–IV of T. (Derlethina) tamiraparaniae.

FIGURES 106–109. Teloganodes (Didgeodes) palnius. 106, young larva in dry condition, to show relief; 107–108, larval exuviae of fore, middle and hind legs.

FIGURES 110–111. Teloganodes (Didgeodes) palnius, male larval exuviae of abdominal terga I–X and sternum IX.

FIGURES 112–122. Teloganodes (Didgeodes) palnius. 112–113, thorax and head of male imago; 114, abdominal terga and sterna of male imago; 115, subimaginal exuviae of mesonotum; 116–117, hind wing of male imago, in falling and transmitted light; 118–119, fore, middle and hind legs of male imago; 121–122, subimaginal exuviae of hind and fore legs.

FIGURES 123–129. Teloganodes (Didgeodes) palnius, male genitalia. 123, genitalia of imago, ventral view; 124, genitalia of subimago; 125, subimaginal exuviae of gonostylus; 126–127, penis of imago, dorsal view; 128, larval abdominal sternum IX and protopenis with developing subimaginal penis inside, dorsal view; 129, outline of subimaginal penis developing in larval protopenis.Abbreviations: gp, gonopore; pgs, protogonostylus; p, subimaginal penis developing in larval protopenis, pp, larval protopenis.

FIGURES 130–136. Teloganodes (Didgeodes) palnius, eggs. 130, egg under light microscope; 131, polar cap in external view and polar cap in internal view; 132–136, eggs under scanning electron microscope.

FIGURES 65–68. Teloganodes (Teloganodes) velutinus sp. n. (holotype). 65–66, wings of female imago in falling and transmitted light; 67–68, hind wing, enlarged, in falling and transmitted light.