taxonID	type	description	language	source
03C41A4F5D1F60262A80401CCD392AB2.taxon	description	(Figs. 8 – 19)	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D1F60262A80401CCD392AB2.taxon	materials_examined	Materials examined. Photos of paratype provided by Zoological Survey of India (ZSI), Southern Regional Centre, Chennai, India. 2 L-S-IJ (AMC / ZN / 199), 2 L-S-I ♀ (AMC / ZN / 200), South India, Tamil Nadu, Madurai District, Vaigai river, 10 ° 08 ′ 32 ′′ N, 77 ° 93 ′ 20 ′′ E, 192 m; 3. X. 2020, colls. P. Srinivasan & R. Isack.	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D1F60262A80401CCD392AB2.taxon	diagnosis	Diagnosis. Caenis maduraiensis can be distinguished from all other Indian representatives of Caenis by the following combination of characters, in the imago: 1) base of antennal flagellum not dilated; 2) foremargin between lateral and frontal ocelli slightly bowed (Fig. 9); 3) foretarsus segment 2 with an apico-median projection (Muthukatturaja and Balasubramanian 2021; Fig. 24); 3) penis broad, with rounded lobes of moderate length (Fig. 10); 4) forceps marginally narrowed to the tip, with a short spine bent medially and basally with a small rounded bulging in the outer margin (Fig. 10). Larva: 1) cuticle of femora of all legs light brownish-ochre, with diffuse light and darker areas; tibiae and tarsi light brownish-ochre (Fig. 11); 2) forefemur with a transverse row of 6 – 7 strongly developed spatulate setae on ¾ of distal region (Fig. 11); 3) proximal inner margin of forefemur with a row of long hair-like bristles (Fig. 11); 4) hindclaw with a row of very fine microdenticles (Fig. 13); 5) hind margin of sternum IX posteriorly protruding and triangular rounded on the apex (Fig. 14). Egg: 1) chorion strongly pored with two epithemata of coiled-rope-type with numerous small terminal knobs, located at the poles (Fig. 18); 2) micropyle short and triangular. Additions to the description. Detailed descriptions of the imago and larva of Caenis maduraiensis are given by Muthukatturaja and Balasubramanian (2021). However, several important diagnostic characters of the imago and larva were not described in the original description. Male imago (Fig. 8). Foremargin between lateral and frontal ocelli slightly bowed (Fig. 9). Forceps marginally narrowed to the tip, with a short spine bent medially and basally with a small rounded bulging in the outer margin (Fig. 10). Larva. Legs. Cuticular coloration: Femora of all legs light brownish-ochre, with diffuse light and darker areas; tibiae and tarsi light brownish-ochre. Foreleg. Femur with a transverse row of 6 – 7 strongly developed spatulate setae on ¾ of distal region (Fig. 11), row of long hair-like bristles present on 1 / 3 of the proximal inner margin. Hindleg. Dorsal surface of femur with only a few spatulate setae on the proximal half (Fig. 12). Claw with a row of very fine microdenticles, subequal in size (Fig. 13). Abdomen. Hind margin of sternum IX posteriorly protruding, triangular, rounded on the apex (Fig. 14); shagreen on dorsal side of sternum IX with 6 – 7 irregular rows of very small denticles parallel to the hind margin (Fig. 15). Egg. Length: 105 – 110 μm; width: 45 – 55 μm. Elongated (Fig. 16); chorion strongly pored (Fig. 18) with two epithemata of coiled-rope-type with numerous small terminal knobs, located at the poles (Fig. 18). Epithemata of a modified C. perpusilla subtype (Fig. 17). Micropyle short and triangular.	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D1F60262A80401CCD392AB2.taxon	discussion	Discussion. Formerly Srinivasan et al. (2021 a), misidentified specimens of C. maduraiensis as Caenis nigropunctatula based on the similar kind of genitalia of the male imago. However, C. maduraiensis can be distinguished from C. nigropunctatula by, in imago, i) bowed foremargin between lateral and frontal ocelli, whereas, in C. nigropunctatula, fore margin between lateral and frontal ocelli straight (Malzacher 2015; Fig. 4 l); ii) basal part of the forceps with a small rounded bulging in the outer margin, whereas, in C. nigropunctatula, no bulging in the basal part of the forceps (Malzacher 2015; Fig. 1 c – i). In larva, i) dorsal surface of forefemur with a transverse row of 6 – 7 strongly developed spatulate setae on ¾ of distal region, whereas, in C. nigropuctatula, no transverse row in the dorsal surface of forefemur (Malzacher, 2015); ii) foreclaw without any denticulation, whereas, in C. nigropunctatula, foreclaw with a row of strong denticles (Malzacher 2015; 2 d); iii) shagreen on dorsal side of sternum IX with 6 – 7 irregular rows of very small denticles parallel to the hind margin, whereas, in C. nigropunctatula, no shagreen field present on the sternum IX (Malzacher, 2015).	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D1F60262A80401CCD392AB2.taxon	distribution	Distribution. Vaigai river, Madurai, Tamil Nadu, India.	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D1F60262A80401CCD392AB2.taxon	biology_ecology	Ecology. Larvae of Caenis maduraiensis were collected in the water temperature ranges between 24 ° C – 26 ° C; pH 7.2 – 7.3. Substratum is mainly made of cobbles and pebbles. The larvae of Caenis maduraiensis shared habitat with Choroterpes (Euthraulus) latus (Leptophlebiidae), Tenuibaetis sp. (Baetidae), Labiobaetis operosus (Baetidae), Nigrobaetis klugei (Baetidae), Tricorythus meenakshi (Tricorythidae), Caenis venkataramani sp. n. (Caenidae) and Clypeocaenis kaveri (Caenidae).	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D19602E2A804110CBBE29D6.taxon	description	(Figs. 20 – 57)	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D19602E2A804110CBBE29D6.taxon	materials_examined	Materials examined. Holotype. L-S-IJ, South India, Tamil Nadu, Madurai District, Vaigai river, 9 ° 95 ′ 52 ′′ N, 78 ° 06 ′ 59 ′′ E, 192 m, 16. VI. 2021, colls. P. Srinivasan & R. Isack (AMC / ZN / 253). Paratypes. 1 L-SJ, 2 L-S-I ♀, 2 larvae (AMC / ZN / 254), 1 larva (Reg. No. ZSI – SRC / I / E / 742) with same label data as holotype.	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D19602E2A804110CBBE29D6.taxon	diagnosis	Diagnosis. Caenis kaegies sp. n. can be distinguished from all other Caenis species by the following combination of characters: Imago: 1) terga I – VI with more or less intense blackish transverse bands (Fig. 22); 2) scutellum darkly pigmented with anvil-shaped marking (Fig. 28); 3) base of antennal flagellum not dilated (Fig. 23); 4) prosternal sclerites bell-shaped (Fig. 24); 5) foretarsus segments 2 – 4 each with a small tongue-shaped apico-median projection (Fig. 25); 6) penis broad, with short rounded lobes (Fig. 26); 7) forceps short, basally broadened, consisting of a strong spine with blunt apex equipped with apical tuft of long spines (Fig. 27). Larva: 1) genae distinctly bulged; 2) pronotum and mesonotum denticulate without any bulging margins; 3) forefemur with a transverse row of 7 – 8 strongly developed spatulate setae (Fig. 39); 4) hindclaw with 3 – 4 basal denticles increasing in size distally, and a row of microdenticles, decreasing in size towards the distal end (Fig. 47); 6) dorsal surface of tergalius II with numerous scales and 4 – 5 spatulate setae on the 2 / 3 rd half of Y-shaped ridge (Fig. 49); 7) hind margin of sternum IX rounded with numerous minute indentations medially (Fig. 52). Egg: 1) chorion finely pored with a cap-like epithema (Fig. 55); 2) micropyle with mouth not broadened (Fig. 56).	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D19602E2A804110CBBE29D6.taxon	description	Description. Male imago (Fig. 20). Measurements. Body length: 1.8 mm; forewing length: 1.3 mm; foreleg length: 1.7 mm; midleg length: 0.7 mm; hindleg length: 0.8 mm; cercus length: 4.8 mm. Ratios. Head (see Malzacher 2015; Fig. 4 k): c: a = 2.3, a: b = 1.1; Leg: fore femur: fore tibia = 0.51; fore tibia: fore tarsus = 1.42; fore leg: hind leg = 2.10; segments of fore tarsus 1 st: 2 nd: 3 rd: 4 th: 5 th = 1: 4.6: 2.4: 1.9: 1. Coloration. Head: Vertex with two more or less intense dark brownish transverse bands (Fig. 23). Antenna: scape and pedicel pale. Thorax: Prothorax dark brownish stripes medially and laterally, posterior margin of pronotum with dark brownish transverse band. Mesonotum generally pale with two black longitudinal bands in the sub medial area; scutellum darkly pigmented with anvil-shaped marking (Fig. 21); mesonotal suture darkly pigmented; prosternum, mesosternum, and metasternum pale yellowish. Wings hyaline, costa, and subcostal veins reddish-brown. Legs whitish, except apical part of femora and tibiae with a dark brownish patch. Abdomen: Terga I – VI with more or less intense blackish transverse bands, terga VII – IX (Fig. 22) mostly colourless medially and laterally with intense blackish stripes, tergum X mostly colourless. Cerci translucent. Head (Fig. 23). Fore margin between lateral and frontal ocelli slightly bowed. Pedicel 2.5 times the length of scape. Base of the antennal flagellum not dilated. Thorax. Prosternal sclerites forming a bell-shape; base of the triangle washed with dark brownish pigmentation (Fig. 24). Foretarsus segments 2 – 4 with a small tongue-shaped apico-median projection (Fig. 25) equipped with strong small spines. Abdomen. Tergum II without a finger-like process. Lateral filaments short. Genitalia and sternum IX as in Fig. 26. Penis broad, with short rounded lobes, hind margin with a well-developed medial incision. Styliger sclerite broad with very short apophyses. Forceps longer than penis lobe, basally broadened, consisting of a strong spine with blunt apex equipped with apical tuft of long spines (Fig. 27). Female imago (Fig. 28). Measurements. Body length: 3.8 mm; forewing length: 2.6 mm. Coloration similar to that of males. Terga I – VI with blackish transverse band strongly pronounced compared to that of males. Mature larva (Fig. 29). Measurements. Body length: 3.4 – 3.5 mm in female; 2.5 – 2.7 mm in male. Cerci length: 1.7 – 2 mm in female; 1.2 – 1.4 mm in male. Antennae length: 0.8 – 1 mm. Head. Length 0.40 mm, width 0.67 mm. General coloration brown, with a dark brownish transverse band between lateral ocelli; vertex dark brown with branch-like markings (Fig. 29). Hind margin without setae, antenna with thin setae on each articulation. Pedicel 1.5 times longer than scape and with 3 – 4 simple setae on lateral margins, genae distinctly bulged in lateral view. Mouthparts: Labrum (Fig. 31) twice as broad as long, medial emargination with thick setae, lateral margin with long simple setae, dorsal and ventral surface with scattered long, fine simple setae. Hypopharynx with minute hair-like setae on the apical margin and superlingua with long simple setae on the lateral margins. Left mandible. Outer incisor with four denticles; inner incisor with two denticles; medial margin without any process between mola and incisors (Fig. 32). Right mandible. Both outer and inner incisors with two denticles; medial margin with a small process between mola and incisors (Fig. 33). Dorsal surface and outer margin of both mandibles scattered with a row of long, strongly spatulate setae (Fig. 34). Maxilla (Fig. 35). Threesegmented maxillary palp; length ratio of palp segments 1: 0.6: 0.9; segment I with a row of five bipinnate bristles on the outer margin (Fig. 36); segment III with a longitudinal row of long simple setae the inner margin. Labium. Glossa with few small spines laterally; paraglossa with scattered long, spine-like setae (Fig. 37); three-segmented labial palp with length ratio of 1: 0.9: 0.5 (Fig. 37); segment I with a row of seven bipinnate bristles in the outer margin, segment II with long hair-like setae all over the surface and in the outer margin; outer marginal surface with a row of 5 – 7 pectinate setae, segment III with 6 – 8 spine-like setae on the inner margin and two transverse rows of long, spine-like setae on the apex along with scattered long hair-like setae on the surface and outer margin. Thorax. Pronotum and mesonotum dark brownish; epidermal pigmentation similar to that of imago (Fig. 30). Mesonotum with denticulate margins without any bulging. Legs. Cuticular coloration: Femora light brownish with diffuse light and dark areas; tibiae and tarsi light brownish. Coxal processes nearly semi-circular with denticulate margins. Foreleg (Fig. 38): lengths of femur: tibia: tarsus: claw 0.38: 0.28: 0.23: 0.14 mm; femur with a transverse row of 7 – 8 strongly developed spatulate setae on ¾ of the distal region (Fig. 39); proximal outer margin consists of few spatulate setae; inner margin with row of long hair-like setae on the proximal half; tibia with longitudinal row of 5 – 6 spatulate setae on dorsal surface; outer margin with few hair-like setae (Fig. 40); tarsi with longitudinal row of two bipinnate bristles on the distal end; outer and inner margins with few hair-like setae; claw slender with four minute basal denticles (Fig. 41). Midleg (Fig. 42): lengths of femur: tibia: tarsus: claw 0.36: 0.22: 0.21: 0.15 mm. Femur with scattered spatulate bristles all over the surface; outer margin consists of a row of long spatulate setae; tibia with longitudinal row of 5 – 6 spatulate setae on dorsal surface (Fig. 43); outer margin with row of short spine-like setae; tarsi with a longitudinal row of six stout, bipinnate bristles of variable in size; claw (Fig. 44) long, broad, and curved with six basal denticles. Hindleg (Fig. 45): lengths of femur: tibia: tarsus: claw 0. 40: 0.31: 0.19: 0.15 mm. Femur similar to that of midleg; tibia with longitudinal row of 5 – 6 spatulate setae on dorsal surface; outer margin with row of long spine-like setae; tarsi similar to that of midleg (Fig. 46); claw strongly curved with 3 – 4 basal denticles increasing in size distally, and a row of microdenticles, decreasing in size towards the distal end (Fig. 47). Abdomen. Terga I, VII, and VIII dark brown; terga IX and X light brown; others whitish and laterally translucent. Tergalius II with diffuse light and dark brown areas without any shading medially and remaining areas with dark brown patches (Fig. 49). Tergalius II about twice the length of tergalius I. Tergum I without posteromedian process; tergum II with a broadly blunt triangular posteromedian process and denticulate hind margin (Fig. 48); tergalius II with Y-shaped ridges poorly developed, inner ridge posteriorly reduced (Fig. 49); dorsal surface with numerous scales and 4 – 5 spatulate setae on the anterior 2 / 3 rd half of Y-shaped ridge (Fig. 49); left margin of Y-shaped ridge with a row of long simple setae with few short spatulate setae. Right margin of Y-shaped ridge with a row of small simple setae. Ventral row of microtrichia originates at anterior 1 / 5 th length of the tergalius II and ends in the posteromedial region; microtrichia elongated, more or less parallel-sided, and pinnate (Fig. 50). Tergalius III – VI with numerous filaments (Fig. 51). Posterolateral processes on tergum I absent; terga II – III with slightly marked posterolateral processes; terga IV – IX with well-developed posterolateral processes. Hind margins of tergum VII with long hair-like setae and tergum VIII with long hair-like setae along with few spatulate setae and terga IX and X with small denticles. Hind margin of sternum IX rounded with numerous minute indentations medially (Fig. 52), shagreen on dorsal side of sternum IX with 8 – 9 irregular rows of very small denticles parallel to the hind margin (Fig. 53). Cerci translucent. Egg. Length: 115 – 125 μm; width: 40 – 50 μm. Elongated (Fig. 54); chorion finely pored with a cap-like epithema (Fig. 55); micropyle small, situated at the subequatorial plane with mouth not broadened (Fig. 56), with visible circular sperm guide (Fig. 57).	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D19602E2A804110CBBE29D6.taxon	etymology	Etymology. This species is named in honour of Dr. K. G. Sivaramakrishnan who is the mentor of the authors T. Sivaruban and S. Barathy, who has significantly contributed to the Indian Ephemeroptera. The species “ kaegies ” is an abbreviated patronym of Dr. K. G. Sivaramakrishnan, popularly known as “ KGS ” and hence the species name.	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D19602E2A804110CBBE29D6.taxon	distribution	Distribution. Vaigai river, Madurai, Tamil Nadu, India.	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D19602E2A804110CBBE29D6.taxon	biology_ecology	Ecology. Larvae of Caenis kaegies sp. n. were collected in the riverine ecosystem with high amount of organic pollution, in which temperature ranges between 25 ° C – 27 ° C; pH 7.3 – 7.4. Substratum is mainly made of cobbles and silt. The larvae of the Caenis kaegies sp. n. shared their ecological niche with the larvae of Cloeon sp. (Baetidae) and Caenis venkataramani sp. n. (Caenidae).	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D19602E2A804110CBBE29D6.taxon	discussion	Discussion. Caenis kaegies sp. n. is distinguished from other Oriental species of Caenis by the darkly pigmented scutellum and bell-shaped prosternal triangle in imago. The larva of Caenis kaegies sp. n. closely resembles that of another Indian species, C. limai. However, it is distinguished from C. limai by the absence of bulging in the mesothorax and reduced number of spatulate setae in the transverse row of the forefemur.	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D1160302A8047F6CB0B2E96.taxon	description	(Figs. 58 – 99)	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D1160302A8047F6CB0B2E96.taxon	materials_examined	Materials examined. Holotype. L-S-IJ, South India, Tamil Nadu, Madurai District, Vaigai river, 10 ° 08 ′ 86 ′′ N, 77 ° 85 ′ 28 ′′ E, 204 m, 24. IX. 2020, colls. P. Srinivasan & R. Isack (Reg. No. ZSI – SRC / I / E / 743). Paratypes. 1 L-S-I ♀ (Reg. No. ZSI – SRC / I / E / 744), 2 L-S-IJ, 1 L-S-I ♀, 5 larvae (AMC / ZN / 201), South India, Tamil Nadu, Madurai District, Vaigai river, 9 ° 95 ′ 52 ′′ N, 78 ° 06 ′ 59 ′′ E, 144 m, 13. VI. 2021, colls. P. Srinivasan & R. Isack. 2 L-S-IJ, Tamil Nadu, Madurai District, Karuppaurani lake, 9 ° 94 ′ 07 ′′ N, 78 ° 18 ′ 84 ′′ E, 132 m, 24. V. 2020, colls. P. Srinivasan & R. Isack. 1 L-S-I ♀, South India, Tamil Nadu, Madurai District, Vaigai river, 9 ° 95 ′ 52 ′′ N, 78 ° 06 ′ 59 ′′ E, 192 m, 16. VI. 2021, colls. P. Srinivasan & R. Isack (AMC / ZN / 202).	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D1160302A8047F6CB0B2E96.taxon	diagnosis	Diagnosis. Caenis venkataramani sp. n. can be distinguished from all other Caenis species by the following combination of characters: Imago: 1) terga I – VI whitish with transverse black tinges (Fig. 60); 2) scutellum pale (Fig. 59); 3) base of antennal flagellum not dilated; 4) prosternal sclerite bell-shaped (Fig. 62); 5) foretarsus segments 2 – 4 each with a small tongue-shaped apico-median projection (Fig. 64); 6) penis narrow, more or less heart shaped, medio-laterally with short rounded lobes, hind margin with a well-developed medial incision; (Fig. 66) 7) basal half of forceps broad, abruptly narrowed in the apical part, apically with a long spine (Fig. 67). Larva: 1) genae distinctly bulged; 2) mesonotum with margins denticulate with slight bulging (Fig. 79); 3) forefemur with a transverse row of 6 – 7 strongly developed spatulate setae (Fig. 82); 4) hindclaw strongly bent with 3 very small basal denticles and a row of microdenticles (Fig. 91); 5) tergalius II with Y-shaped ridges poorly developed, inner one posteriorly reduced (Fig. 92); 6) hind margin of sternum IX broadly or triangularly rounded (Fig. 96); 7) shagreen on dorsal side of sternum IX with 8 – 9 irregular rows of very small denticles parallel to the hind margin. Egg: 1) two cap-like epithemata at the poles (Fig. 97); 2) chorionic surface smooth with transverse slender micropylar canal between polar caps (Fig. 98); 3) micropyle small with mouth not broadened (Fig. 99).	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D1160302A8047F6CB0B2E96.taxon	description	Description. Male imago (Fig. 58). Measurements. Body length: 3.3 mm; forewing length: 2.1 mm; foreleg length: 2.1 mm; midleg length: 1.1 mm; hindleg length: 1.3 mm; cercus length: 7.8 mm. Ratios. Head (see Malzacher 2015; Fig. 4 k): c: a = 2.3, a: b = 1; Leg: fore femur: fore tibia = 0.61; fore tibia: fore tarsus = 1.66; fore leg: hind leg = 1.6; segments of fore tarsus 1 st: 2 nd: 3 rd: 4 th: 5 th = 1: 4.5: 3.1: 2.7: 1.4 Coloration. Head: Vertex with a dark brownish transverse band between lateral ocelli. Antenna: scape and pedicel pale. Thorax (Fig. 59): Pronotum with two black spots submedially and dark stripes laterally. Mesonotum dark brownish with stripes in the lateral areas; scutellum pale; mesonotal suture darkly pigmented; prosternum light brownish with dark stripes laterally, mesosternum, and metasternum light brownish, laterally with dark stripes. Wings hyaline, costa and subcostal veins reddish-brown. Legs whitish, except apical part of femora with a dark brownish patch; tibia dark brownish. Abdomen (Fig. 60): General coloration of terga whitish; terga I – VI whitish with transverse black tinges; terga VII – IX whitish with darkened lateral areas. Cerci translucent. Head (Fig. 61). Fore margin between lateral and frontal ocelli straight. Pedicel two times the length of scape. Base of the antennal flagellum not dilated. Thorax. Prosternal sclerites strong, forming an apically blunt or protruded isosceles triangle, without transverse strip (Figs. 62, 63). Foretarsus segments 2 – 4 each with a small tongue-shaped apico-median projection (Fig. 64) equipped with strong small spines (Fig. 65). Abdomen. Tergum II without a finger-like process. Lateral filaments short. Genitalia and sternum IX as in Fig. 66. Penis narrow, more or less heart shaped, medio-laterally with short rounded lobes, hind margin with a well-developed medial incision (Fig. 67); styliger sclerite with very short apophyses. Basal half of forceps broad, abruptly narrowed in the apical part, apically with a long spine (Fig. 67). Female imago (Fig. 68). Measurements. Body length: 5.3 mm; forewing length: 2.8 mm. Coloration is similar to that of males. Terga I – VI transverse band strongly pronounced compared to that of males. Mature larva (Fig. 69). Measurements. Body length (Fig. 13): 4.9 – 5.1 mm in female; 3.3 – 3.5 mm in male. Cerci length: 3.2 – 3.3 mm in female; 1.5 – 1.6 mm in male. Antennae length: 1.5 – 1.7 mm. Head. Length 0.54 mm, width 0.82 mm. General coloration brown, vertex with a dark brownish transverse band between lateral ocelli. Hind margin without setae, antenna with fine, thin setae on each articulation. Pedicel two times the length of scape and with 3 – 4 simple setae on lateral margins (Fig. 71), genae distinctly bulged in lateral view. Mouthparts: Labrum (Fig. 72) twice as broad as long, medial emargination with thick setae, lateral margin with long simple setae, dorsal and ventral surface with scattered long, fine simple setae. Hypopharynx (Fig. 73) with minute hair-like setae on the apical margin and superlingua with long simple setae on the lateral margins. Right mandible. Outer incisor with three denticles and inner incisor with two denticles; medial margin with a small process between mola and incisors (Fig. 74). Left mandible. Outer incisor with five denticles; inner incisor with three denticles; medial margin without any process between mola and incisors (Fig. 75). The dorsal surface and outer margin of both mandibles scattered with a row of long, simple setae. Maxilla (Fig. 76). Three-segmented maxillary palp and with a ratio of 1: 0.6: 1; segment I with a row of five curved, spine-like setae on the outer margin; segment III with a longitudinal row of long simple setae near the inner marginal surface. Labium (Fig. 77). Glossa and paraglossa scattered with long, spine-like setae; three-segmented labial palp with length ratio of 1: 0.8: 0.6 (Fig. 77); segment I with a row of ten bipinnate bristles in the outer margin, segment II with long hair-like setae with 7 – 8 pectinate setae in the outer margin; surface with a bipinnate seta (Fig. 79), segment III with 6 – 8 spine-like setae in the inner margin and two transverse rows of long, spine-like setae on the apex along with scattered long hair-like setae on the surface and outer margin. Thorax. Pronotum and mesonotum dark brownish and epidermal pigmentation similar to that of imago. Mesonotum with margins denticulate with slight bulging (Fig. 78). Legs: Cuticular coloration: Femora, tibiae and tarsi light brownish. Coxal processes nearly semi-circular with denticulate margins. Foreleg (Fig. 81): lengths of femur: tibia: tarsus: claw 0.55: 0.44: 0.32: 0.15 mm; femur with a transverse row of 6 – 7 strongly developed spatulate setae (Fig. 83) on ¾ of the distal region (Fig. 82); near the outer marginal surface a longitudinal row of spatulate setae present; distal outer margin consists of few spatulate setae; inner margin with row of long hair-like setae on the proximal half; tibia with longitudinal row of 4 – 5 spatulate setae on dorsal surface; outer margin with few hair-like setae; tarsi with longitudinal row of seven bipinnate bristles; outer and inner margins with few hair-like setae; claw slender without any denticulation (Fig. 80). Midleg (Fig. 84): lengths of femur: tibia: tarsus: claw 0.57: 0.36: 0.29: 0.15 mm. Femur with scattered spatulate bristles all over the surface; outer margin consists of a row of long spatulate setae; tibia with longitudinal row of 6 – 7 spatulate setae on dorsal surface; outer margin with row of short spine-like setae; tarsi with a longitudinal row of seven stout, bipinnate bristles, increasing in size distally; claw (Fig. 85) long, and curved without any denticles. Hindleg: lengths of femur: tibia: tarsus: claw 0.59: 0.47: 0.32: 0.15 mm. Femur (Fig. 86) similar to that of midleg; tibia (Fig. 87) with longitudinal row of 6 – 7 spatulate setae on dorsal surface (Fig. 88); outer margin with row of long spine-like setae; tarsi with a longitudinal row of seven stout, bipinnate bristles, increasing in size distally near the inner margin and a longitudinal row of spine-like setae on the inner margin (Fig. 89); claw strongly bent with three very small basal denticles (Fig. 91), and a row of microdenticles (Fig. 90). Abdomen. All terga nearly light brownish. Tergalius II with diffuse light and dark brown areas without any shading medially and with dark brown patches on the other regions (Fig. 92). Tergalius II about twice the length of tergalius I. Tergum I lack posteromedian process; tergum II with a broadly blunt triangular posteromedian process with denticulate hind margin; Tergalius II with Y-shaped ridges poorly developed, inner ridge posteriorly reduced (Fig. 92); dorsal surface with numerous scales and 3 – 4 spatulate setae on the 1 / 3 rd half of Y-shaped ridge; left margin of Y-shaped ridge with a row of long simple setae with few small spatulate setae. Right margin of Y-shaped ridge with a row of small simple setae. Ventral row of microtrichia originates at anterior 1 / 5 th length of the tergalius II and ends in the posteromedial region; microtrichia elongated, more or less parallel-sided, and pinnate (Fig. 93). Tergalius III – VI with numerous filaments (Fig. 94). Posterolateral processes on tergum I absent; terga II – III with slightly marked posterolateral processes; terga IV – IX with well-developed posterolateral processes. Hind margins of tergum VII with long hair-like setae and tergum VIII with few long hair-like setae (Fig. 95) and terga IX and X with small denticles. Hind margin of sternum IX broadly or triangularly rounded (Fig. 96), shagreen on dorsal side of sternum IX with 8 – 9 irregular rows of very small denticles parallel to the hind margin. Cerci translucent. Egg. Length: 110 – 115 μm; width: 70 – 75 μm; oval (Fig. 97); two cap-like epithema at the poles (Fig. 97); chorionic surface smooth with transverse slender micropylar canal between polar caps (Fig. 98), micropyle small, situated at the subequatorial plane with mouth not broadened (Fig. 99).	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D1160302A8047F6CB0B2E96.taxon	etymology	Etymology. This new species is named in honour of Dr. K. Venkataraman (mentor for the authors T. Sivaruban and S. Barathy) for his remarkable contribution to the Indian Ephemeroptera.	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D1160302A8047F6CB0B2E96.taxon	distribution	Distribution. Vaigai river, Madurai, Tamil Nadu, India.	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D1160302A8047F6CB0B2E96.taxon	biology_ecology	Ecology. Larvae of Caenis venkataramani sp. n. were collected in the water temperature ranges between 24 ° C – 26 ° C; pH 7.2 – 7.3. Substratum is mainly made of cobbles and pebbles. The larvae of the Caenis venkataramani sp. n. shared their habitat with the larvae of Choroterpes (Euthraulus) latus (Leptophlebiidae), Tenuibaetis sp. (Baetidae), Labiobaetis operosus (Baetidae), Nigrobaetis klugei (Baetidae), Cheleocloeon vaigaiensis (Baetidae), Tricorythus meenakshi (Tricorythidae), Caenis maduraiensis (Caenidae) and Clypeocaenis kaveri (Caenidae).	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D1160302A8047F6CB0B2E96.taxon	discussion	Discussion. The male imago of Caenis venkataramani sp. n. is distinguished from other Oriental species of Caenis, except C. maratha by the shape of forceps, in which the basal part is very broad and the apical part is abruptly narrowed. It is distinguished from C. maratha by a well-developed medial incision in the hind margin of the penis. The larva of Caenis venkataramani sp. n. closely resembles that C. maduraienis and C. nigropunctatula. However, it is distinguished from C. maduraienis and C. nigropunctatula by the denticulation of the hind claw and by the mesonotal bulging in the larva and by the shape of the forceps in the imago.	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D0F603F2A80413CCD4C2AB2.taxon	description	(Figs. 100 – 142)	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D0F603F2A80413CCD4C2AB2.taxon	materials_examined	Materials examined. Holotype. L-S-IJ, South India, Tamil Nadu, Madurai District, Nagamalai, Pulluthu stream, 9 ° 95 ′ 30 ′′ N, 78 ° 03 ′ 92 ′′ E, 212 m, 13. X. 2020, colls. P. Srinivasan & R. Isack (Reg. No. ZSI – SRC / I / E / 740). Paratypes. 2 L-SJ, 2 L-S-I ♀ (AMC / ZN / 255), 7 larvae (AMC / ZN / 256), 1 larva (Reg. No. ZSI – SRC / I / E / 741) with same label data as holotype.	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D0F603F2A80413CCD4C2AB2.taxon	diagnosis	Diagnosis. C. arunachalami sp. n. can be distinguished from all other Caenis species by the following combination of characters: Imago: 1) dark brownish body coloration and terga III – VII and X with a darker longitudinal line medially (Fig. 100); 2) base of antennal flagellum well dilated (Fig. 101); 3) prosternal sclerites forming an open triangle with concave sides (Fig. 103); 4) foretarsus segments 2 – 4 each with an apico-median projection (Fig. 102); 5) contrasting coloration of forceps and penis (Fig. 104); 6) penis narrow without any bulging lobes; posterior margin nearly straight without any medial emargination (Fig. 105); 7) forceps short, subcylindrical, broad, apically with a long hook-like spine equipped with 2 – 3 small spines near the apex (Fig. 106). Larva: 1) genae distinctly bulged (Fig. 109); 2) femur of each leg ochre with contrasting dark brownish patch in the 3 / 4 th distal apex; tibia and tarsus of each leg ochre with dark brownish band at middle (Fig. 129); 3) mesonotum with margins denticulate; 4) forefemur with a transverse row of 6 – 7 strongly developed spatulate setae on ¾ of distal region (Fig. 122); 5) hindclaw long and slightly curved, with a row of very fine microdenticles, medial denticles larger compared to basal denticles (Fig. 131); 6) tergalius II with left margin of Y-shaped ridge bearing row of long simple setae in the proximal half and row of spatulate setae in the distal half (Fig. 132); 7) hind margin of sternum IX posteriorly protruding and blunt triangular with a rounded tip on the apex (Fig. 137). Egg: 1) chorion smooth with a flat epithema of coiled-rope type located at the pole (Figs. 140, 141); 2) micropyle with broadened mouth (Fig. 142).	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D0F603F2A80413CCD4C2AB2.taxon	description	Description. Male imago (Fig. 100). Measurements. Body length: 2.5 mm; forewing length: 2.2 mm; foreleg length: 2.1 mm; midleg length: 1 mm; hindleg length: 1.2 mm; cercus length: 7.7 mm. Ratios. Head (see Malzacher 2015; Fig. 4 k): c: a = 2.2, a: b = 1.3; Leg: fore femur: fore tibia = 0.58; fore tibia: fore tarsus = 1.27; fore leg: hind leg = 1.75; segments of fore tarsus 1 st: 2 nd: 3 rd: 4 th: 5 th = 1: 3.1: 2.8: 2.3: 1.9 Coloration. Head: Vertex with intense blackish transverse band. Antenna: scape and pedicel light brownish, flagellum whitish shaded with gray at base. Thorax: Prothorax light brownish medially and dark brownish laterally; prosternum medially dark brownish and laterally yellowish brown. Mesonotum and metanotum dark brown; mesosternum and metasternum dark brownish. Wings hyaline, costa, and subcostal vein reddish-brown. Legs whitish, except apical part of femora and tibiae with a dark brownish patch. Abdomen: Terga I – II dark brownish, terga III – VIII with transverse light brownish tint medially and paler laterally and tergum IX & X darker; terga III – VII & X with a darker longitudinal line medially, in tergum VIII & IX, medial longitudinal line poorly expressed. Cerci translucent. Head (Fig. 101). Foremargin between lateral and frontal ocelli convex. Pedicel twice the length of scape; pedicel well dilated laterally. Base of the antennal flagellum well dilated. Thorax. Prosternal sclerites narrow, forming an open triangle with concave sides; transverse strip long, present just above the opening, prosternal triangle entirely washed with dark brownish pigmentation (Fig. 103). Foretarsus segments 2 – 4 apically with a small tongue-shaped apico-median projection, equipped with small strong spines (Fig. 102). Abdomen. Tergum II without a finger-like process. Lateral filaments short. Genitalia and sternum IX as in Fig. 104. Penis short, broad, without any bulging lobes, nearly in the posterior margin of styliger sclerite (Fig. 105). Styliger sclerite with apophyses of moderate length (Fig. 106). Forceps short, subcylindrical, broad, apically with a long hook-like spine equipped with 2 – 3 small spines near the apex (Fig. 106). Genitalia entirely washed with brownish pigmentation and with very minute hairs; penis and forceps translucent; styliger sclerite dark brownish; central sclerite light brownish. Female imago (Fig. 107). Measurements. Body length: 3.8 mm; forewing length: 2.6 mm. Coloration is similar to that of males. Terga III – VIII brownish tint strongly pronounced compared to that of males. Mature larva (Fig. 108). Measurements. Body length: 3.3 – 3.5 mm in female; 2.4 – 2.5 mm in male. Cerci length: 3 mm in female; 1.3 mm in male. Antennae length: 0.7 – 0.8 mm. General body coloration is usually dark brown dorsally and pale brown ventrally. Head. Length 0.37 mm, width 0.59 mm. General coloration dark brown, with dark blackish transverse band between lateral ocelli; vertex dark brown without any markings (Fig. 109). Hind margin without setae, antenna with fine, thin setae on each articulation at every 3 rd segment. Pedicel twice the length of scape and with 1 – 2 simple setae on lateral margins, genae distinctly bulged (Fig. 109). Mouthparts: Labrum (Fig. 110) twice as broad as long, medial emargination with thick setae, lateral margin with long simple setae, dorsal and ventral surface with scattered long, fine simple setae (Fig. 111). Hypopharynx (Fig. 112) with minute hair-like setae on the apical margin and emarginate, superlingua with long simple setae on the lateral margins (Fig. 113). Right mandible (Fig. 114). Outer incisor with three denticles in which the outermost denticle possesses 4 – 5 long, fine setae; inner incisor with two denticles; medial margin with a small process between mola and incisors. Left mandible (Fig. 115). Outer incisor with four denticles; inner incisor with three denticles; medial margin without any process between mola and incisors. Dorsal surface of both mandibles scattered with scales and row of long setae laterally and a few long setae near the surface of the outer margin. Maxilla (Fig. 116). Three-segmented maxillary palp and with ratio of 1: 0.60: 0.94; segment I with row of 4 – 6 spines on outer margin; segment III with longitudinal row of long setae near inner marginal surface. Labium (Fig. 117). Glossa with five small spines laterally; paraglossa with scattered long simple setae (Fig. 118); three-segmented labial palp with length ratio of 1: 0.81: 0.50; segment I with row of bipinnate setae in the outer margin (Fig. 119), segment II with scattered long hair-like setae all over the surface and in the outer margin; outer marginal surface with a row of 9 – 10 bipinnate setae, segment III with seven spine-like setae in the inner margin and two transverse rows of four spine-like setae on the apex. Thorax. Pronotum dark brown medially with traphezoidal marking medially; mesonotum dark brown. Margins of mesonotum denticulate with slight bulging. Legs: Cuticular coloration (Fig. 120, 126, 129): Femur of each leg ochre with contrasting dark brownish patch in the 3 / 4 the distal apex; tibia and tarsus of each leg ochre with dark brownish band at middle. Hypodermal coloration: Coloration of legs coinciding with cuticular coloration. Coxal processes semicircular with denticulate margins. Trochanter with four small spine-like setae on the inner margin and 4 – 5 spatulate setae near the surface of the outer margin. Foreleg (Fig. 120): lengths of femur: tibia: tarsus: claw 0.30: 0.22: 0.17: 0.08 mm; femur (Fig. 121) with a transverse row of 6 – 7 strongly developed spatulate setae on ¾ of distal region (Fig. 122); distal outer margin consists of 4 – 5 slightly developed spatulate setae; femora covered with numerous scale bases; tibia with longitudinal row of strongly developed spatulate setae on dorsal surface (Fig. 123), cluster of a large pectinate seta, three bipectinate setae and two long strongly developed spatulate setae present on its distal region; tarsi with longitudinal row of spine-like setae, increasing in size towards the distal half (Fig. 124); proximal inner marginal surface bears two bipectinate setae; claw long, curved and pointed with 4 – 6 minute denticles, which are of different in size (Fig. 125). Midleg (Fig. 126): lengths of femur: tibia: tarsus: claw 0.28: 0.22: 0.18: 0.08 mm. Femur with scattered strongly developed spatulate setae all over the surface; distal outer margin consists of 4 – 5 slightly developed spatulate setae; tibia bears a longitudinal row of seven strongly developed spatulate setae on its surface; distal region of tibia with a large apically blunt bipinnate seta; tarsi with longitudinal row of bipinnate setae, increasing in size distally (Fig. 127); midclaw (Fig. 128) bears seven denticles (four on dorsal side and three on ventral side). Hindleg (Fig. 129): lengths of femur: tibia: tarsus: claw 0.30: 0.25: 0.20: 0.09 mm. Femur with strongly developed spatulate setae all over the surface; outer margin (both proximal and distal margin) with slightly developed spatulate setae; tibia same as of midleg; tarsi with two longitudinal rows of pectinate and bipinnate setae (Fig. 130); claw long and slightly curved, 2 basal denticles, and with a row of very fine microdenticles, medial denticles larger compared to basal one (Fig. 131). Abdomen. Terga I, VIII, and IX dark brown; tergum X light brown; others whitish and laterally translucent. Tergum I lack posteromedian process; tergum II with a broadly blunt triangular posteromedian process and denticulate hind margin; posterolateral processes on terga I – II absent; tergum III with slightly marked posterolateral processes; terga IV – VII with well-developed posterolateral spines processes (Fig. 136); terga VIII – IX posterolateral spines subequal in size. Hind margins of terga VII and VIII with bristles and terga IX and X with small denticles. Tergalius II about twice the length of tergalius I. Tergalius II with complete and well-developed Y-shaped ridge (Fig. 132); dorsal surface with numerous scales and 4 spatulate setae on the 2 / 3 rd half of Y-shaped ridge (Fig. 133). Left margin of Y-shaped ridge with row of long simple setae in the proximal half and row of spatulate setae in the distal half margin. Right margin of Y-shaped ridge with row of long simple setae. Ventral row of microtrichia originates at anterior 1 / 5 th length of the tergalius II; microtrichia more elongated and pinnate (Fig. 134). Tergalius III – VI with numerous filaments (Fig. 135). Hind margin of sternum IX posteriorly protruding and triangular rounded on the apex (Fig. 137); shagreen on dorsal side of sternum IX with 4 – 5 irregular rows of very small denticles parallel to the hind margin (Fig. 138). Cerci translucent. Egg. Length: 105 – 115 μm; width: 70 – 80 μm. Oval (Fig. 139); chorion smooth with a flat epithema of coiledrope type located at the pole (Figs. 140, 141); micropyle situated at the subequatorial plane and slightly bent with broadened mouth (Fig. 142).	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D0F603F2A80413CCD4C2AB2.taxon	etymology	Etymology. This species is named in honour of Dr. M. Arunachalam (Central University of Kerala, School of Biological Sciences, Department of Animal Science / Zoology, Periye, India) who is the mentor and guide for the authors T. Sivaruban and S. Barathy, for his outstanding contribution to the benthic macroinvertebrates.	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D0F603F2A80413CCD4C2AB2.taxon	distribution	Distribution. Nagamalai hills, Madurai, Tamil Nadu, India (Southern Eastern Ghats).	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D0F603F2A80413CCD4C2AB2.taxon	biology_ecology	Ecology. Larvae of Caenis arunachalami sp. n. were collected in a freshwater stream of 10 m wide with 80 % canopy cover. The water temperature ranges between 22 ° C – 24 ° C; pH 7.1 – 7.3. Substratum is mainly made of cobbles, pebbles, leaf litter with silt and organic matter. The larvae of the Caenis arunachalami sp. n. shared their habitat with the larvae of Labiobaetis sp. (Baetidae).	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D0F603F2A80413CCD4C2AB2.taxon	discussion	Discussion. The male imago of Caenis arunachalami sp. n. is distinguished from other Oriental species of Caenis by the unique coloration of the body and genitalia. The coloration of the adult closely resembles that of the Ethiopian species C. gretathunbergae Malzacher 2021 (Malzacher 2021, Fig. 15), however, the new species can be distinguished from C. gretathunbergae, by the shape of forceps and penis in the male imago and by the shape of sternum IX in the larva (Malzacher 2021).	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D00603D2A804518CC1B29AE.taxon	description	(Figs. 143 – 151)	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D00603D2A804518CC1B29AE.taxon	materials_examined	Materials examined. 1 J imago, 1 ♀ imago, South India, Tamil Nadu, Madurai District, Vaigai river, 10 ° 08 ′ 32 ′′ N, 77 ° 93 ′ 22 ′′ E, 192 m, 1. VIII. 2022, colls. P. Srinivasan & R. Isack (AMC / ZN / 211, 212).	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D00603D2A804518CC1B29AE.taxon	description	Description. Male imago (Fig. 143). Measurements. Body length: 2.9 mm; forewing length: 1.9 mm; foreleg length: 1.8 mm; midleg length: 1 mm; hindleg length: 1.2 mm; cercus length: 6.7 mm. Ratios. Head (see Malzacher 2015; Fig. 4 k): c: a = 2.2; a: b = 1.1; Leg: fore femur: fore tibia = 0.57; fore tibia: fore tarsus = 1.37; fore leg: hind leg = 1.5; segments of fore tarsus 1 st: 2 nd: 3 rd: 4 th: 5 th = 1: 3.6: 2.1: 1.6: 0.9 Coloration. Head: Vertex light brownish. Antenna: scape and pedicel pale. Thorax: Prothorax mostly pale with dark brownish transverse band in the posterior margin. Mesonotum generally dark brownish; scutellum darkly pigmented with fin-shaped processes; mesonotal suture darkly pigmented; prosternum, mesosternum, and metasternum pale. Wings hyaline, costa, and subcostal veins reddish-brown. Legs whitish, except apical part of femora and tibiae with a dark brownish patch. Abdomen: Terga mostly colourless with a well-developed brownish transverse band and a longitudinal black stripe medially on terga III – VI (Fig. 144). Cerci translucent. Head (Fig. 145). Fore margin between lateral and frontal ocelli slightly bowed. Pedicel two times the length of scape. Base of the antennal flagellum slightly dilated. Thorax. Prosternal sclerites strong, forming an apically blunt isosceles triangle, without transverse strip. Foretarsus segments 2 – 3 each with a lateral and a median projections and segment 4 with an apico-median projection equipped with strong small spines (Fig. 146). Abdomen. Tergum II without a finger-like process. Lateral filaments short. Penis broad, with rounded lobes, hind margin with a well-developed medial incision, Penis mediolaterally with a tongue-shaped process. Forceps basally broadened with more or less parallel sides, consists of a long tuft of spines with a strong spine more or less fused with few thin spines (Fig. 147). Other genital details are missing. Female imago. Measurements. Body length: 3.7 mm; forewing length: 2.4 mm. Coloration is similar to that of males. Transverse band in terga III – VI strongly pronounced compared to that of males. Larva. Unknown. Egg. Length: 110 – 120 μm; width: 75 – 85 μm. Oval-shaped (Figs. 148, 149); chorion smooth with a flat epithema forming a coil of fine threads on the pole (Fig. 150); micropyle long, situated at the subequatorial plane with mouth not broadened, with well visible circular sperm guide (Fig. 151).	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D00603D2A804518CC1B29AE.taxon	distribution	Distribution. Vaigai river, Madurai, Tamil Nadu, India.	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D00603D2A804518CC1B29AE.taxon	discussion	Discussion. The unnamed species Caenis sp. 1 is similar to C. ulmeriana and C. limai by the shape of the forceps, but differs from them by the lateral and median projections in foretarsus segments 2 – 3 and an apico-median projection in segment 4 in the male imago (Malzacher 2015; Malzacher and Sangpradub 2020; Srinivasan et al. 2023). The eggs of Caenis sp. 1 distinguished from both C. ulmeriana and C. limai by the length of the micropyle (Malzacher and Sangpradub 2020; Srinivasan et al. 2023).	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D02603C2A80441FCB102A42.taxon	description	(Figs. 152 – 156)	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D02603C2A80441FCB102A42.taxon	materials_examined	Materials examined. 5 ♀ imagoes, South India, Tamil Nadu, Madurai District, Karuppaurani lake, 9 ° 94 ′ 07 ′′ N, 78 ° 18 ′ 84 ′′ E, 132 m, 24. V. 2020, colls. P. Srinivasan & R. Isack (AMC / ZN / 266).	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D02603C2A80441FCB102A42.taxon	description	Description. Female imago (Fig. 152). Measurements. Body length: 2.7 mm; forewing length: 2.5 mm; foreleg length: 1.2 mm; midleg length: 1.2 mm; hindleg length: 1.1 mm; cercus length: 1.4 mm. Coloration. Head: Vertex with dark brownish transverse markings between lateral ocelli. Antenna: scape and pedicel light brownish. Thorax: Prothorax darkened laterally. Mesonotum generally light brownish with two longitudinal bands in the sub medial area; scutellum pale; mesonotal suture darkly pigmented; prosternum, mesosternum, and metasternum pale yellowish. Wings hyaline, costa, and subcostal vein reddish-brown. Legs whitish, except apical part of femora and tibiae with a dark brownish patch. Abdomen: Terga I – IV with a welldeveloped black transverse band, terga IX – X mostly colourless. Cerci translucent. Head. Fore margin between lateral and frontal ocelli slightly bowed. Pedicel two times the length of scape. Base of the antennal flagellum slightly dilated. Thorax. Prosternal sclerites anteriorly converging, forming a broadly rounded triangle; transverse strip short. Abdomen. Tergum II without a finger-like process. Lateral filaments short. Male imago and larva. Unknown. Egg. Length: 110 – 120 μm; width: 75 – 85 μm. Oval-shaped (Figs. 153); chorion smooth with an epithemata of coiled-rope-type with numerous small terminal knobs on the pole (Figs. 154, 155). Epithemata of a modified C. perpusilla subtype. Micropyle moderate, situated at the subequatorial plane with mouth not broadened, with well visible circular sperm guide (Fig. 156).	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D02603C2A80441FCB102A42.taxon	distribution	Distribution. Karuppaurani lake, Madurai, Tamil Nadu, India.	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D02603C2A80441FCB102A42.taxon	discussion	Discussion. The unnamed species Caenis sp. 2 is similar to C. ulmeriana by the egg structure, however, it is distinguished by the smooth chorionic surface (Malzacher and Sangpradub 2020).	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D0360032A804489CB992F9A.taxon	description	(Figs. 157 – 171)	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D0360032A804489CB992F9A.taxon	materials_examined	Materials examined. 1 L-S-IJ, 3 L-S-I ♀, 5 larvae, South India, Tamil Nadu, Madurai District, Vaigai river, 9 ° 95 ′ 52 ′′ N, 78 ° 06 ′ 59 ′′ E, 144 m, 8. VII. 2022, colls. P. Srinivasan & R. Isack (AMC / ZN / 257). 10 larvae, South India, Tamil Nadu, Madurai District, Vaigai river, 10 ° 08 ′ 32 ′′ N, 77 ° 93 ′ 22 ′′ E, 192 m, 1. VIII. 2022, colls. P. Srinivasan & R. Isack (AMC / ZN / 257). Additions to the description. Detailed imago and larval descriptions of Clypeocaenis kaveri are given by Balasubramanian and Muthukatturaja, 2021. However, several important diagnostic characters of the imago, subimago and larva were not included in the original description. Female imago (Fig. 157). Coloration: Terga whitish (eggs under the body give the appearance of yellowish color to the tergum). Posterior half of terga I – IX with dark brownish transverse band (Fig. 158). Prosternal sclerites trapezoid with concave lateral sides with a transverse blackish strip in the fore margin and with well-developed basolateral dark pigmentation (Fig. 160). Subimago. Legs. Cuticular coloration: Femora of all legs light brownish-ochre, with diffusive light and darker areas; tibiae and tarsi light brownish-ochre (Fig. 161). In both sexes of all leg pairs, tibiae and tarsomeres are covered with microtrichia (Figs. 162, 163). Larva (Fig. 159). Abdomen. Tergalius II with a well developed medial ridge, forming an elevated triangular keel (Fig. 164). Ventral row of microtrichia ending far from the hind margin, consists of 2 – 3 irregular rows of cluster of 2 – 6 spines medially (Fig. 165). Hind margin of sternum IX broadly rounded with numerous indentations (Fig. 166); shagreen on dorsal side of sternum IX with 5 – 6 irregular rows of very small denticles parallel to the hind margin (Fig. 167). Egg. Length: 115 – 120 μm; width: 65 – 70 μm. Oval-shaped (Fig. 168); chorion smooth (Fig. 169) with a flat epithema forming a coil of fine threads with numerous small terminal knobs on one pole (Fig. 170). Micropyle short, situated at the subequatorial plane with mouth slightly broadened (Fig. 171).	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D0360032A804489CB992F9A.taxon	distribution	Distribution. Kaveri river (Karnataka), Vaigai river (Madurai, Tamil Nadu).	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D0360032A804489CB992F9A.taxon	biology_ecology	Ecology. Larvae of Clypeocaenis kaveri were collected in the water temperature ranges between 24 ° C – 26 ° C; pH 7.2 – 7.3. Substratum is mainly made of cobbles and pebbles. The larvae of Clypeocaenis kaveri shared their habitat with Choroterpes (Euthraulus) latus (Leptophlebiidae), Tenuibaetis sp. (Baetidae), Labiobaetis operosus (Baetidae), Nigrobaetis klugei (Baetidae), Cheleocloeon vaigaiensis (Baetidae), Tricorythus meenakshi (Tricorythidae), Caenis maduraiensis (Caenidae), Caenis venkataramani sp. n. and Clypeocaenis kaveri (Caenidae).	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D3E60012A804690CAA12ACF.taxon	description	(Male adult characters of Caenis sp. 2 is unknown)	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D3E60012A8042CECAA12EBB.taxon	description	(Egg characters of Caenis maratha are unknown)	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
03C41A4F5D3E60012A8044F1CAA12C0A.taxon	description	(Larval characters of Caenis maratha, Caenis sp. 1, and Caenis sp. 2 are unknown)	en	Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran (2023): Contribution to the knowledge of family Caenidae (Insecta: Ephemeroptera) from Madurai District, Tamil Nadu. Zootaxa 5258 (1): 39-75, DOI: 10.11646/zootaxa.5258.1.2, URL: http://dx.doi.org/10.11646/zootaxa.5258.1.2
