Baetiella armata Braasch, 1983

Vasanth, M., Selvakumar, C., Subramanian, K. A., Sivaramakrishnan, K. G. & Sinha, Bikramjit, 2020, New record of the genus Baetiella Uéno, 1931 (Ephemeroptera: Baetidae) from India with description of a new species and new records for five species, Zootaxa 4763 (4), pp. 563-578 : 568-570

Baetiella armata Braasch, 1983

( Figs 19–33 )

Material examined. 3 larvae, INDIA, Arunachal Pradesh, Lower Subansiri district, Paniya stream, 27.81791 N, 94.09502 E, 993 m, 14.vi.2017, colls. K. A. Subramanian & M. Vasanth (Reg. No. I/E/252).

Mature larva. Body length 3.5–4.0 mm ( Fig. 19 ), cerci 3.2–3.7 mm, median caudal filament absent.

Head. Antennae pale brown, approximately 1.3 times the width of head ( Fig. 20 ); dorsal surface of scape and pedicel without fine setae. Labrum ( Fig. 21 ) rectangular, approximately 2.0 times wider than long; anteromedian notch deep with a small rounded lobe at the base, and each side with one medial long seta and a row of 12–13 robust, simple submarginal setae, fine and simple scattered setae laterally; ventrally bordered with feathered setae along the anterior margin. Hypopharynx ( Fig. 22 ) with lingua rounded and superlinguae broadly truncate, covered with abundant fine setae. Left mandible ( Fig. 24 ): incisors fused with 6–7 denticles, prostheca robust with 3 blunt and 4 acute denticles apically. Right mandible ( Fig. 23 ): incisors with visible fusion line, outer incisors with 4 denticles and inner incisors with 3 denticles, inner incisor margin smooth without fine setae, prostheca with denticles apically and distinctly more slender than the one on left mandible, edge between prostheca and molar smooth without serration, molar plate-like. Maxillae ( Fig. 25 ) with three canines and one tooth-like dentiseta on crown of galealacinia, a row of 4–5 long basal setae and basis of galealacinia without hump seta; maxillary palpus 2-segmented and terminal segment shorter than basal segment without tip at apex. Labium ( Fig. 26 ): glossae shorter than paraglossae, with a row of 7–8 stout setae along the inner margin dorsally and 2 long robust blunt setae at the apex; paraglossae approximately 2 times wider than glossae, with 3 rows of setae ventrally and 2–3 stout acute setae along the inner margin dorsally; labial palpus 3-segmented, terminal segment conical with a distinctive small tip at apex; 2nd segment with small inner-apical lobe; dorsal surface with numerous pores on the basal segment.

Thorax. Coloration pale brown, dorsum without tubercles. Posterior margin of metanotum with a protuberance medially ( Fig. 19 ). Hindwing pads reduced. Legs pale brown, femora creamy shaded with light brown medially and a paler longitudinal stripe near dorsal margin, tibiae and tarsi brown. Femora with a row of long and simple setae on dorsal margin, approximately 1/4 to 1/2 of femur width; femoral villopore reduced; tibiae with regular row of fine, simple setae dorsally; tarsi with a row of sparse, fine, simple setae dorsally and a row of 3–4 robust, blunted setae ventrally increasing in length towards apex ( Figs 27–29 ); tarsal claw with a row of 6–7 denticles and a bowed subapical setae ( Fig. 30 ). All legs without coxal gill.

Abdomen. Dorsally pale brown. Posterior margin of terga I–IX each with a single posteromedian protuberance ( Fig. 19 ); terga surface without blunt denticles on posterior margin. Abdominal sterna generally yellowish-white; surface of sterna I–IX smooth, without any denticles. Gills on segments I–VII, oval and without visible tracheation, surface scattered with numerous pores, margin smooth with fine simple setae, coloration white or reddish depending on the type of habitats ( Fig. 32 ). Paraproct with numerous pores on surface and 7–8 scale-like setae along the inner margin ( Fig. 33 ). Median caudal filament reduced to one segment, cerci smaller than body length ( Fig. 19 ).

Diagnosis. Baetiella armata Braasch, 1983 can be distinguished from other species of this genus by the following combination of characters: in larva (i) terminal segment of maxillary palp without a small tip at apex ( Fig. 25 ); (ii) second segment of labial palp with small inner-apical lobe; and (iii) inner margin of paraproct with 7–8 scale-like setae ( Fig. 33 ).

Distribution. Nepal and India (Arunachal Pradesh) ( Fig. 81 ).

Remarks. Braasch (1983) described Baetiella armata based on larvae from Nepal. Here we provide an improved larval description of B. armata , based on fresh material from our collections. Our new data represent the first report of this species from India.

Figures

FIGURES 81. Distribution map of Baetiella in Arunachal Pradesh, India.

FIGURES 19–33. Larva of Baetiella armata Braasch, 1983. 19. Habitus in dorsal view; 20. Antenna; 21. Labrum; 22. Hypopharynx; 23. Right mandible; 24. Left mandible; 25. Maxilla; 26. Labium; 27. Fore leg; 28. Midleg; 29. Hind leg; 30. Hind tarsal claw; 31. Gill V; 32. Gill VII; 33. Paraproct.