Derlethina tamiraparaniae Selvakumar, Sivaramakrishnan & Jacobus

Selvakumar, C., Sivaramakrishnan, K. G., Jacobus, Luke M., Janarthanan, S. & Arumugam, M., 2014, Two new genera and five new species of Teloganodidae (Ephemeroptera) from South India, Zootaxa 3846 (1), pp. 87-104 : 99-101

Derlethina tamiraparaniae Selvakumar, Sivaramakrishnan & Jacobus , n. sp.

Figs. 78–92 .

Materials examined. Holotype: Male larva, India, Tamilnadu, Tamiraparani river, Papanasam, 8°42’37.1” N, 77°22’03.1” E, 108 m, 15.V.2013, Colls. C. Selvakumar& K. G. Sivaramakrishnan [ZSI-I/E 15]. Paratypes: Two larvae same data as holotype [UM]. One larva, India, Karnataka, Agumbe, Jogi Gunndi falls, 13°29’55.95” N, 75°06’10.85” E, 514 m, 02.V.2013, Colls. C. Selvakumar& K. G. Sivaramakrishnan [UM]. Description. Larva.

Body length up to 3.5–4.0 mm and 4.0– 4.5 mm in male and female respectively, cerci slightly longer than body length. Body flattened, eyes in dorsal position brownish in male larvae ( Fig. 78 ).

General colouration greyish black dorsally; scape and flagellum of the antennae whitish, pedicel blackish; legs yellowish, femora darker, with four dark brown maculae on dorsal face, maculae sometimes merging; apex of tibiae brownish.

Head: Outer margin of head fringed with row of forked setae from behind eyes to labrum insertion. Antennae length 0.9–1.0 times head width, flagellum with 15 or16 segments. Labrum with wide anteromedian emargination; anterior margin covered by thin setae; dorsal face with row of long and simple setae ( Fig. 79 ). Hypopharynx with lingua broad, superlinguae quadrangular, outer margin almost straight, with row of simple and long setae at apex ( Fig. 80 ). Mandibles slender with one thin seta in middle of outer margin; outer incisor of left mandible ( Fig. 81 ) composed of one tooth indented basally, inner incisor with two teeth inserted transversally, one small and pointed, one large and rounded; prostheca reduced with several well-developed seta-like projections; no setae below mola; right mandible ( Fig. 82 ) with outer incisor composed of one tooth, slightly indented medially; inner incisor with two teeth; prostheca reduced to seta-like cluster; row of three or four long, thin setae below mola and several short setae above mola. Maxilla moderately slender, with well-developed canine ( Fig. 83 );, two dentisetae and three long setae on inner apical portion and group of long, simple setae at crown; inner margin at base of lacinia with one feathered and long seta dorsally and two short, feathered setae ventrally ( Fig. 83 ); maxillary palp highly reduced. Labial palp three-segmented, but articulation between segments 1 and 2 obscure; segment 3 ca. 2.0 times as long as wide at base ( Fig. 84 ).

Thorax: Prothorax and mesothorax without tubercles on dorsal face. Forefemur dilated, ca. 1.5–1.6 times longer than wide; outer margin covered by stout and long setae, and dorsal face broad and dilated with transverse row of stout and blunt setae ( Fig. 85 ) almost reaching inner margin; inner margin with row of long and thin setae almost reaching apex of femur. Foretibia with one visible row of long and thin setae on inner margin, and another on outer margin. Middle femur more slender, ca. 2.0–2.2 times longer than wide; dorsal and inner margins with row of long and stout setae ( Fig. 86 ). Tibia with a row of long and stout setae on inner margin, and row of long, thin setae on outer margin. Hind leg similar, ca. 2.5 times longer than wide, outer margin not concave ( Fig. 87 ). Tarsal claw hooked, with three or four pointed teeth medially, and two pointed teeth subapically, with inner tooth reduced; apex of claw with two rows of three or four thin setae laterally.

Abdomen: Terga without median tubercles on segments I–IV, but poorly developed on segments V–IX, and absent on segment X ( Fig. 88 ). Posterolateral projections absent from segments II–IV, present and well-developed on segments V–IX; lateral margins of terga with very long and thin setae ( Fig. 89 ). Gills on abdominal segments II–IV ( Figs. 90–92 ), gills II–III with ventral lobes, gill IV without ventral lobe; gills II with dorsal lamella operculate, oval and with margin entire; gills III with dorsal lamella incised medially; gills IV with dorsal lamella incised medially; ventral lobe flabelliform, well developed and purple on gills II and III. Cerci with stout setae longer than length of corresponding segment. Terminal filament highly reduced.

Winged stages. Unknown.

Etymology. This species named after the type locality, the Tamiraparani River.

Diagnosis. Derlethina tamiraparaniae , n. sp., can be distinguished from D. eloisae by the following combination ofcharacters: (i) gill IV incised ( Fig. 92 ); (ii) outer margin of hind femora not concave ( Fig. 87 ) and (iii) prostheca of left mandible reduced, but with several well-developed seta-like projections ( Fig. 81 ).

Figures

FIGURES 78 – 92. Derlethina tamiraparaniae, n. sp. 78. Larva, dorsal habitus; 79. Labrum; 80. Hypopharynx; 81. Left mandible; 82. Right mandible; 83. Maxillae; 84. Labium; 85. Foreleg; 86. Midleg; 87. Hindleg (arrow indicates outer margin of hind femora not concave); 88. Abdominal median tubercles; 89. Abdomen, ventral view; 90 – 92. Gills II – IV.