Torleya dibruensis Selvakumar, Martynov & Jacobus 2021, sp. nov.
Creators: name: Martynov, Alexander V.
name: Selvakumar, C.
name: Subramanian, K. A.
name: Sivaramakrishnan, K. G.
name: Vasanth, M.
name: Sinha, Bikramjit
name: Jacobus, Luke M.
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Ephemeroptera
Ephemerellidae
Torleya
Torleya dibruensis

description: Torleya dibruensis Selvakumar, Martynov & Jacobus, sp. nov.
(Figs 11–13)
Type material. Holotype: larva, INDIA, Arunachal Pradesh, Papum Pare District, Dibru River, 27.147655°N, 93.74908°E, h ~ 128 m a.s.l., 22.iv.2015, Colls. K.A. Subramanian & Bikramjit Sinha — Reg. No. 5606/H13 [ZSI]. Paratypes: 1 larva, same data as holotype— Reg. No. 5607/H13 [ZSI]; 2 larvae, INDIA, Arunachal Pradesh, Lower Subansiri District, Paniya stream, 27.81791°N, 94.09502°E, h ~ 993 m a.s.l., 14.vi.2017, Colls. K.A. Subramanian & M. Vasanth — Reg. No. SRC-I/E 510 [ZSI].
Description. Late larval instar: Length of body 3.5–3.8 mm; cercus and median caudal filament subequal, each 1.5–1.8 mm. General color light brown, with variable brown shading and markings; front of head, outer and inner margins of legs and lateral margins of abdominal terga covered with long, hair-like setae (Figs 11A, 12A, B).
Head: Head with one pair of distinct, blunt occipital tubercles bear small short stout setae. The same scattered stout setae cover head. Color light brown with variable brown markings; frons pale; two dark brown, rounded spots situated between occipital protuberances and compound eyes. Areas around paired ocelli yellowish. Antennal scape and pedicel light brown; flagellar segments yellowish-brown, with fine, hair-like setae at apex of each segment; hair-like setae nearly one-third length of respective segment. Clypeus and genae densely covered with long hair-like setae (Fig. 12A). Labrum (Fig. 11B) brown; anterior notch shallow and wide; anterolateral angles weakly expressed, rounded; dorsal surface with dense, transverse row of cilia-like setae. Superlinguae of hypopharynx with row of setae on anterior margin; lingua with very sparse and tiny setae on dorsal and ventral surfaces, apex convex (Fig. 11C). Mandible external margin with scattered hair-like setae basally and pair of long cilia-like setae medially (Fig. 11D, E). Maxilla (Fig. 11F) with few distal hair-like setae; palp 3-segmented, with visible articulation; spinous processes short. Labium with cilia-like setae on ventral surface; segment III of maxillary palp rounded, about one-third length of segment II (Fig. 11G).
Thorax: Pronotum without distinct protuberances. Mesonotum with several small, protuberances. Mesonotum with transverse brown shading medially (Fig. 11A); tip of fore wingpads pale to white. Legs pale, distinctly flattened, especially fore femur (Fig. 13B–D). Dorsal surface of forefemur with irregular transverse row of long, pointed, stout setae proximally; outer and inner margins with rows of long hair-like setae and long, pointed, stout setae (Fig. 13A, B); dorsal surface of middle and hind femora smoky brown, with a few short stout setae; outer and inner margins with long, pointed, stout setae and long, hair-like setae (Fig. 13C, D). Tibiae of all legs distinctly wider than tarsi. Each claw with 2–3 medial denticles, palisade of four to five long subdistal denticles, and subapical seta (Fig. 13E).
Abdomen: Terga with dark longitudinal medial line and lateral shading (Figs 11A, 12B). Dorsal lamella of gill III rounded, extending to middle of tergum VIII (Fig. 12B), apically rounded, with fine distal setae, brown, trilobed pattern indistinct (Fig. 13F); gill III operculate; ventral lamellae of gills III–VI bifurcate and multifoliate (Fig. 13G). Terga I–V and VIII–X mostly pale; terga VI–VII usually brown (Fig. 12B). Terga V–IX with spatulate, stout setae on posterior margins (setae progressively shorter on segments VI–VIII); terga VII and VIII with hair-like and spatulate, stout setae; terga IV–VII and IX with paired posterior protuberances, bears small stout setae with rounded apices; terga VIII and X without paired posterior protuberances; posterior protuberances very small on tergum IV and IX; largest on terga V–VII, usually bearing 4–6 short spatulate stout setae; Lateral parts of posterior margin of tergum VIII with row of spatulate, stout setae. Segments IV–IX with posterolateral projections. Segment IX distinctly narrower than segment VIII (Fig. 12B). Sterna pale, with few short, hair-like setae. Caudal filaments pale to white, with broad, dark brown band medially; tips dark brown; apex of each segment with spatulate, stout setae and fine hair-like setae.
Adults. Unknown.
Diagnosis. Larvae of Torleya dibruensis sp. nov. can be distinguished from other representatives of the genus by the following combination of characters: (i) head with one pair of blunt occipital tubercles; (ii) head, legs and abdomen with areas densely covered with long, hair-like setae (Figs 11A, 12A, B, 13A–D); (iii) claw with 2–3 medial denticles, palisade of four to five long subdistal denticles on the inner margin, and subapical seta (Fig. 13E); (iv) terga V–VII with paired blunt protuberances, usually bearing four to six short spatulate, stout setae (Fig. 11A); (v) gills rounded, gill III entirely cover following gills (Figs 11A, 12B, 13F, G); (vi) foreleg with irregular transverse row of long pointed, stout setae at proximal part of dorsal surface; same setae presented on outer and inner margins (Fig. 13A, B); (vii) maxillary palp present, short (Fig. 11F); (viii) labial palp segment III about one-third length of segment II (Fig. 11G).
Etymology. This species is named after the type locality, Dibru River, Arunachal Pradesh.
Distribution. India-China border region.
Habitat. Larvae of the species were collected in rivers and large streams with cobble and sandy bottom and numerous boulders (Fig. 20D).
Remarks. Torleya longforceps from Fujian, in far eastern China (Gui et al. 1999), is the only species of Torleya unknown in the larval stage, and we consider it unlikely (based on biogeography) to be conspecific with this new species, which is unknown as alates.
description: Published as part of Martynov, Alexander V., Selvakumar, C., Subramanian, K. A., Sivaramakrishnan, K. G., Vasanth, M., Sinha, Bikramjit & Jacobus, Luke M., 2021, Overview of Indian Hyrtanellini (Ephemeroptera: Ephemerellidae), with new species and records from related regions, pp. 451-482 in Zootaxa 4975 (3) on pages 467-470, DOI: 10.11646/zootaxa.4975.3.2, http://zenodo.org/record/4808307