Hyrtanella grandipennis ( Zhou, Su & Gui, 2000 )

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 : 461-464

Hyrtanella grandipennis ( Zhou, Su & Gui, 2000)

( Figs 6–9 )

Torleya grandipennis Zhou, Su & Gui, 2000

Material examined: INDIA: 4 larvae (two in slides ## 688, 689, with Euparal) Uttarakhand State, Chamoli district, Alaknanda River (700 m above mouth of the Pindar River ), 30.267728 N, 79.220931 E, h ~ 800 m a.s.l., 5.ii.2011, Palatov D.M. and Chertoprud M. V . leg.— IN Indi6Hyrsp1/1-4 [ NMNH NASU].

Diagnosis. Hyrtanella grandipennis can be distinguished from other Indomalayan Hyrtanellini by the following combination of characters in the larval stage: (i) entire body covered with numerous rounded excrescences ( Fig. 6B–D , 8B, C, E , 9B ); (ii) head with pair of small, rounded occipital tubercles; (iii) maxilla with or without (even in one specimen) very short, single-segmented palp bears hair-like seta ( Fig. 7E–G ); (iv) pro- and mesothorax with variable developed blunt dorsal protuberances; (v) mesothorax with notched anterolateral projections bears few rounded apically stout setae ( Fig. 6B, C ); (vi) claw with no stout, preapical denticle that is larger than the rest, (vii) claw usually with distal palisade of denticles (if absent, probably worn down); (viii) pairs of flattened, rounded apically, widely spaced submedian projections present on terga III(VI, V)–VIII, with those on terga VI–VIII more developed; largest on tergum VIII ( Fig. 9A, B, E, F ); tergum IX without submedian projections or with wide, short and rounded apically ones; (ix) abdomen with distinct and deep chamber for gills, its inner margin presented with posterolateral projections of terga ( Fig. 9A, E, F ); (x) segment IX elongated, with large and pointed posterolateral projections reached posterior margin of tergum X ( Fig. 9A ); (xi) posterior margin of sternum VIII with pair of triangular projections that visible even dorsally ( Fig. 9A, C–F ); (xii) gills III–VI distinctly elongated, especially gill III ( Fig. 9G ). Male imago has (xiii) broad forceps and penis; (xiv) genital forceps segment III elongate, with its length being more than 2x its width; (xv) genital forceps segment II not swollen or bowed, but with a distal bend; (xvi) penes lobes with dorsolateral projections. Imagoes and subimagoes of H. grandipennis also differ from H. pascalae Jacobus & Sartori, 2004 (figs 15–17 in Jacobus & Sartori 2004) from Borneo based on the venation and shape of hind wings. In contrast to H. pascalae , in fore wing of H. grandipennis one of the iCuA divided and attached to CuA; stigmatic area subdivided by a secondary vein into upper and lower rows of several cellules between C and Sc; CuP and AA of fore wing subparallel, not converge toward margin; hind wing with small costal process in middle of margin.

Distribution. Southern mainland China ( Zhou et al. 2000; Jacobus et al. 2004), Vietnam, Thailand (Jacobus et al. 2004) and India (new data).

Remarks. Hyrtanella grandipennis was described originally in Torleya Lestage, 1917 based on the male imago stage ( Zhou et al. 2000). Later, the larval stage of the species was described based on specimens from China, Vietnam and Thailand (Jacobus et al. 2004), and considerable morphological variation within and between these populations was noted. Jacobus & McCafferty (2008) placed this species in Hyrtanella Allen & Edmunds, 1976 based on detailed study and analysis of imaginal and larval characters. Xu et al. (2020) reported this species in Torleya . In their study of mitogenomes, H. grandipennis and T. tumiforceps Zhou & Su, 1997 (junior syn. of Torleya nepalica ( Allen & Edmunds, 1963)) were placed in the same clade, but other species of Hyrtanella and Torleya were not included in the investigation, so no new conclusions can be made about relationships and generic affinities of the various species in Torleya and Hyrtanella beyond those hypothesized by Jacobus & McCafferty (2008: fig. 99) and Ogden et al. (2009: figs 1,2). The male imagoes of H. pascalae and H. christineae Allen & Edmunds, 1976 are not described yet, so adequate comparisons and diagnoses are not yet practical.

Among our specimens of H. grandipennis , we note that a small maxillary palp is variably present or absent (even in one specimen) among the single known population in India. Jacobus et al. (2004) previously hypothesized this feature was variable, even though Vietnam specimens consistently had the palp, and China and Thailand specimens lacked such a palp .

In our opinion, taxonomic status of three close forms of H. grandipennis and their generic position need proper investigation with integrative approach, with molecular, morphological and possibly ecological study. Unfortunately, the Indian specimens at hand were collected in 4% Formaldehyde, and later placed in Ethanol, ruling out the chance of obtaining good DNA sequence data; moreover, only the Chinese form has the male imago described.

Figures

FIGURE 6. Larva of Hyrtanella grandipennis (Zhou, Su & Gui, 2000). A. – total view of larva; B. – anterolateral projections of mesonotum; C. – thorax, dorsal view; D. – head. Scale bar 0.5 mm.

FIGURE 7. Larva of Hyrtanella grandipennis (Zhou, Su & Gui, 2000). A, B.—mandibles; C.—labrum; D.—hypopharynx; E.—maxillary palp; F, G.—maxillae of one specimen; H.—labium; I.—submentum. Black arrows show maxillary palp.

FIGURE 8. Larva of Hyrtanella grandipennis (Zhou, Su & Gui, 2000). A.—fore femur; B.—middle femur; C.—hind femur; D.—tarsal claw; E.—outer margin of hind femur.

FIGURE 9. Larva of Hyrtanella grandipennis (Zhou, Su & Gui, 2000). A.—abdomen, dorsal view; B.—paired submedian projections of terga IV–VIII and the terga dorsal surfaces; C, D.—projections of sternum VIII, ventral view; E, F.—lateral sides of terga VI–VIII; G.—gill III. Black arrows show projections of sternum VIII.