Clypeocaenis malzacheri Srinivasan, Sivaruban, Barathy & Isack 2022
- Dataset
- A new species of Clypeocaenis Soldán 1978 (Ephemeroptera: Caenidae) from Tamil Nadu, India
- Rank
- SPECIES
- Published in
- Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S., Isack, Rajasekaran, Jacobus, Luke M. (2022): A new species of Clypeocaenis Soldán 1978 (Ephemeroptera: Caenidae) from Tamil Nadu, India. Zootaxa 5091 (3): 467-476, DOI: 10.11646/zootaxa.5091.3.6
Classification
- kingdom
- Animalia
- phylum
- Arthropoda
- class
- Insecta
- order
- Ephemeroptera
- family
- Caenidae
- genus
- Clypeocaenis
- species
- Clypeocaenis malzacheri
biology_ecology
Biology. The larvae of Clypeocaenis malzacheri sp. nov. show a significant level of languor in their activity. They live on cobble and pebbles in areas with slow current. They were found in water with temperature ranging between 21 ° C – 23 ° C and pH ranging between 7.1 – 7.3.
description
(Figs. 1 – 8)
distribution
Distribution. Kurangani hills, Tamil Nadu, India.
etymology
Etymology. This species is named after Dr. Peter Malzacher (Ludwigsburg, Germany), in honor of his dedication to caenid mayflies. The epithet “ malzacheri ” is used as a nomen in the genitive case.
materials_examined
Materials Examined. Holotype (in ethanol): Male larva (Reg. No. ZSI – SRC / I / E / 599), South India, Tamil Nadu, Theni district, Kurangani, Kottakudi River, 10 ° 08 ′ 09 ″ N, 77 ° 25 ′ 52 ″ E; 632 m; 28. x. 2020, Pandiarajan Srinivasan & Rajasekaran Isack. Paratypes (also in ethanol): 1 male larva (Reg. No. ZSI – SRC / I / E / 600), 2 male larvae (AMC / ZN / 192), 4 female larvae (AMC / ZN / 193), same data as holotype. Descriptions. Final larval instar. Body length (without cerci): 2.5 – 2.7 mm (male) and 2.9 – 3.1 mm (female); cerci lengths about 1.15 mm; antennae lengths 0.81 – 0.85 mm. General body coloration usually dark brown dorsally and pale yellow ventrally, though sometimes lighter dorsally. Head: General color brownish, with vertex darker with branch-like pigmentation (Fig. 1); epicranial sutures dark. Compound eyes black, ocelli whitish. Scape and pedicel chagrined without any setae; pedicel length 1.6 times length of scape. Frons distinctly protruded to proximal margin of second flagellum segment (Fig. 2 A), with two simple setae on anterior margin with lengths about ¼ length of antenna. Labrum (Fig. 2 B) 2.3 times as broad as long; emargination without any setae; anterior margin with row of long and thin setae; dorsum with few, long and thin setae near anterior margin and lateral margin. Mandibles (Fig. 2 C) with three denticles on outer incisor and two transversely arranged denticles on kinetodontium; basal area below mola chagrined and with no setae; two transverse row of simple setae on the dorso-lateral surface in which apical row bears 4 simple setae and basal row with numerous long, simple setae; basal half of mandible chagrined. Maxilla (Fig. 2 D) with two-segmented palp with protuberance; segment II 3.1 times longer than segment I; distal 3 / 4 of segment II covered with long, thin setae; outer margin of segment I with row of 8 stout setae (n = 4) and inner margin bare. Galea-lacinia with row of 5 long, thin setae in the inner margin. Apical margin of superlingua covered with long, simple setae; hypopharynx with very short spines at apical margin. Labium (Fig. 2 E): glossae ovate with apical margins covered with thin setae; paraglossae bent towards glossae and bluntly pointed, covered with thin setae; palps three-segmented, with segment III longer than segments I and II, segment III with bluntly pointed tip (Fig. 2 F), segment III with two transverse rows of five stout setae at distal margin, segment II with two bipinnate bristles at distal margin (Fig. 2 G), and segment I with seven unipinnate bristles on outer margin (Fig. 2 H). Thorax: Pronotum dark brownish, margins light brownish. Anterolateral areas of pronotum produced. Mesonotum dark brownish. Legs: Evenly covered with scales, coloration pale to medium brown; ovoidal cuticular blank located on the proximal half of ventral surface of each femur of all legs (Fig. 4 A). Foreleg (Fig. 3 A): lengths of femur / tibia / tarsus / claw viz., 0.50 / 0.47 / 0.49 / 0.15 mm. Coxa denticulate with thin setae on inner and outer margins. Femur (Fig. 4 B) with scattered spine-like setae along inner margin; outer margin with long, simple setae present on part of proximal half and row of spatulate setae present on part of distal half; dorsal surface with 3 or 4 stout setae (Fig. 4 B & 4 C). Tibia with two transverse rows of very long filtering setae on dorsal side, prolonged on ventral side in longitudinal direction (Fig. 4 B). Tarsus with loose row of 6 long, simple setae extending nearly longitudinally; outer margin with scattered hair-like setae; 8 – 10 long, bipinnate setae on inner margin. Claw long and slender, with 4 denticles varying in size, basal denticle very small compared to others (Fig. 4 D). Midleg (Fig. 3 B): lengths of femur / tibia / tarsus / claw viz., 0.53 / 0.35 / 0.31 / 0.13 mm. Coxa similar to foreleg. Femur (Fig. 5 A) with rows of spatulate setae on outer and inner margins and two feathery setae near surface of distal half of outer margin. Tibia (Fig. 5 B) inner margin with row of spines on the distal half and one large, monopectinate seta present; outer margin with scattered hair-like setae. Tarsus (Fig. 5 B) inner margins with row of spine-like setae; outer margins with scattered hair-like setae; 4 bipinnate bristles present medially (Fig. 5 C). Claw long and hooked with 3 denticles increasing in size distally (Fig. 5 D). Hindleg (Fig. 3 C): lengths of femur / tibia / tarsus / claw viz., 0.73 / 0.48 / 0.38 / 0.17 mm. Coxa similar to foreleg. Femur (Fig. 5 E) with row of feathered setae on outer margin and row of broadly spatulate and pinnate bristles on inner margin (Fig. 5 F); outer margin with 2 simple setae in distal half (Fig. 5 G). Tibia with row of spatulate setae on outer margin and row of simple setae with broad apices on inner margin. Tarsus and claw similar to midleg. A bdomen: Terga I, VIII, and IX brown; others whitish and laterally translucent. Tergum II (Fig. 6 A) with upright, backwardly curved blunt medial projection; posterior margin with pointed spines; surface with scales. Terga VII and VIII with medial protuberances (Fig. 6 C); posterior margin of tergum VII (Fig. 6 C) with short, bifid setae medially and pinnate setae laterally; terga VIII – X with denticles on posterior margins. Sterna VII – IX light brown; others whitish; hind margin of sternum IX slightly concave and denticulate (Fig. 6 B). Tergalii: tergalius I bluntly pointed, two-segmented; segment II three times as long as segment I. Tergalius II quadrate (Fig. 6 D, 7 A), pale brown, evenly covered with scales (Fig. 6 D); posterior margin with stout, multi-branched bristles; inner margin with row of small, simple setae; outer margin with stout, multi-branched bristles. Tergalii III – VI subtriangular (Fig. 7 B), fringed with some bifid fimbriae. Tergalii III – VI with 45 – 50 filaments (only 13 filaments with 2 branches, all other filaments simple). Cerci translucent. Egg. Length: 115 – 120 μm; width: 60 – 65 μm. Elongate, about twice as long as wide (Fig. 8 A); chorion smooth without any epithema (Fig. 8 B); micropyle of moderate length; mouth not broadened with circular sperm-guide (Fig. 8 C). Imago. Unknown. Larval Diagnosis. The new species has a unique combination of features: (i) frons strongly protruding up to the proximal margin of the second flagellum segment (Fig. 2 A); ii) ovoidal cuticular blank located on the proximal half of ventral surface of each femur of all legs (Fig. 4 A); iii) forefemora lack long setae in the middle of the inner margin (Fig. 4 B); iv) claws with 4 denticles in the foreleg varying in size, basal denticle very small compared to others and, 3 denticles increasing in size distally in the mid and hindleg (Fig. 4 D & 5 D); v) abdominal tergum II with upright, backwardly curved blunt medial projection (Fig. 6 A); and vi) hind margin of abdominal sternum IX slightly concave and denticulate (Fig. 6 B).