Torleya dibruensis Selvakumar, Martynov & Jacobus, 2021

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, Zootaxa 4975 (3), pp. 451-482 : 467-470

publication ID	https://doi.org/ 10.11646/zootaxa.4975.3.2
publication LSID	lsid:zoobank.org:pub:222B81FA-E0F5-43A9-960D-5C9ACC2ADD0A
DOI	https://doi.org/10.5281/zenodo.4808325
persistent identifier	https://treatment.plazi.org/id/1D7287CD-FFC2-D660-FF09-086A0852F8AE
treatment provided by	Plazi
scientific name	Torleya dibruensis Selvakumar, Martynov & Jacobus
status	sp. nov.

Treatment

Torleya dibruensis Selvakumar, Martynov & Jacobus , sp. nov.

( Figs 11–13 View FIGURE 11 View FIGURE 12 View FIGURE 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] GoogleMaps . Paratypes: 1 larva, same data as holotype— Reg. No. 5607/H13 [ ZSI] GoogleMaps ; 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] GoogleMaps .

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 View FIGURE 11 , 12A, B View FIGURE 12 ).

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 View FIGURE 12 ). Labrum ( Fig. 11B View FIGURE 11 ) 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 View FIGURE 11 ). Mandible external margin with scattered hair-like setae basally and pair of long cilia-like setae medially ( Fig. 11D, E View FIGURE 11 ). Maxilla ( Fig. 11F View FIGURE 11 ) 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 View FIGURE 11 ).

Thorax: Pronotum without distinct protuberances. Mesonotum with several small, protuberances. Mesonotum with transverse brown shading medially ( Fig. 11A View FIGURE 11 ); tip of fore wingpads pale to white. Legs pale, distinctly flattened, especially fore femur ( Fig. 13B–D View FIGURE 13 ). 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 View FIGURE 13 ); 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 View FIGURE 13 ). 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 View FIGURE 13 ).

Abdomen: Terga with dark longitudinal medial line and lateral shading ( Figs 11A View FIGURE 11 , 12B View FIGURE 12 ). Dorsal lamella of gill III rounded, extending to middle of tergum VIII ( Fig. 12B View FIGURE 12 ), apically rounded, with fine distal setae, brown, trilobed pattern indistinct ( Fig. 13F View FIGURE 13 ); gill III operculate; ventral lamellae of gills III–VI bifurcate and multifoliate ( Fig. 13G View FIGURE 13 ). Terga I–V and VIII–X mostly pale; terga VI–VII usually brown ( Fig. 12B View FIGURE 12 ). 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 View FIGURE 12 ). 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 View FIGURE 11 , 12A, B View FIGURE 12 , 13A–D View FIGURE 13 ); (iii) claw with 2–3 medial denticles, palisade of four to five long subdistal denticles on the inner margin, and subapical seta ( Fig. 13E View FIGURE 13 ); (iv) terga V–VII with paired blunt protuberances, usually bearing four to six short spatulate, stout setae ( Fig. 11A View FIGURE 11 ); (v) gills rounded, gill III entirely cover following gills ( Figs 11A View FIGURE 11 , 12B View FIGURE 12 , 13F, G View FIGURE 13 ); (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 View FIGURE 13 ); (vii) maxillary palp present, short ( Fig. 11F View FIGURE 11 ); (viii) labial palp segment III about one-third length of segment II ( Fig. 11G View FIGURE 11 ).

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 View FIGURE 20 ).

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.