Epeorus (Epeorus) gilliesi Braasch, 1981

Vasanth, M., Selvakumar, C., Subramanian, K. A., Sivaramakrishnan, K. G. & Sinha, Bikramjit, 2021, Contribution to the study of Epeorus Eaton, 1881 (Ephemeroptera: Heptageniidae) from India, Zootaxa 4991 (3), pp. 499-522 : 508-513

Epeorus (Epeorus) gilliesi Braasch, 1981

( Figs 68–84 )

Material examined: 1 larva, INDIA, Karnataka, Sharavathi river, below Jog falls , 26.xi.1928 [Reg. No. 7348/H13, ZSI, Kolkata] ; 1 larva, Goa, Tambdi Surla , 17.ix.2017; coll. K. A. Subramanian [ZSI/ SRC-I /E-334] .

Description: Mature larva: Body length 13.5 mm; length of caudal filaments 12 mm. Body generally brown ( Fig. 68 ).

Head: Length 1.7 mm, width 3.6 mm; brown ( Fig. 68 ); subquadrangular; anterior and lateral margins convex, with rows of dense hair-like setae directed medially-dorsally-backward and pressed to head; posterior margin slightly concave. Compound eyes grayish black. Antennal scape, pedicels and flagellum brown. Labrum wide, dark brown, anterior margin with 14–15 denticles; long hair-like setae laterally ( Fig. 71 ). Hypopharynx as in Fig. 72 . Mandible with scattered setae along molar area; incisors well developed; outer incisor longer than inner incisor ( Figs 73–74 ). Maxilla as in Fig. 75 . Labium broad, glossae with V-shaped separation, subtriangular; paraglossae slightly expanded laterally; apical segment of palp acutely pointed, dorsal surface with dense row of comb setae ( Fig. 76 ).

Thorax: Pronotum pale brown; mesonotum darker brown with paramedian pair of darker spots anteriorly and pair of lateroparapsidal sutures curved inside posteriorly ( Fig. 68 ). Legs ( Figs 78–80 ): Femora brown; hypodermal spot on dorsal surface; dense row of long setae on outer margin; scattered stout setae on dorsal surface ( Fig. 77 ); margin of tibia with dense hair-like setae. Claw with 5 denticles ( Fig. 81 ).

Abdomen: Abdominal terga brown, a row of spines on posterior margin of segment I–X, terga III–VIII with a pair of brown spots ( Figs 68, 70 ); posterior margin of terga with rather short spines; segments II–VII with long posterolateral extensions; sterna pale with pair of brown color marking on each segments ( Fig. 69 ). Gill I elongated, somewhat extended beneath of abdomen, middle pairs large widely rounded ( Fig. 68 ); Gills II–VII without arched anal ribs ( Figs 82–84 ). Cerci with row of hair-like setae dorsally.

Diagnosis: Epeorus gilliesi can be distinguished from closely related species E. petersi by the following combination of characters: in larva (i) abdominal terga III–VIII with pair of brown spot ( Figs 68–70 ); (ii) a row of spine on posterior margin of segment I–X ( Figs 68–70 ); (iii) posterior edge of the gill 1 elongated ( Fig. 82 ); and (iv) anterior margin of labrum with 14–15 denticles ( Fig. 71 ).

Distribution: India (Karnataka, Goa and Maharashtra).

Remarks: The larva of this species was described from Khandala (Maharashtra), India by Braasch (1981); we provide a supplementary larval description based on our material from south India. Adult stages are unknown.

Figures

FIGURES 68–74. Larva of Epeorus (Epeorus) gilliesi 68. Dorsal view; 69. Abdomen ventral view; 70. Posterior margins of terga; 71. Labrum; 72. Hypopharynx; 73. Left mandible; 74. Right mandible.

FIGURES 75–84. Larva of Epeorus (Epeorus) gilliesi 75. Maxilla; 76. Labium; 77. Dorsal surface of femur; 78. Foreleg; 79. Midleg; 80. Hindleg; 81. Claw; 82. Gill I; 83. Gill III; 84. Gill VII.