Agnetina brevipennis ( Navás, 1912 )

Teslenko, Valentina A., 2024, Eggs of Perlidae (Insecta, Plecoptera) of the Russian Far East, Zootaxa 5551 (1), pp. 91-115 : 102

Agnetina brevipennis ( Navás, 1912)

Figs. 40−44

Material examined. Russia, Far East, Yakutia: 1♂, 1♀, 1 L, Chulman River , above Neryungi town , Lena River basin, 23.07.2010, coll. V. Teslenko; 1♂, 1♀ Sinyaya River, near Pokoyashcichsya Skal , about 80 km before the confluence with Lena River , 2.08.2023, coll. A. Rasshchepkina; Amurskaya Oblast, 1♀, Tu River, Zeya River basin, Amur River basin, 10.09.2007, coll. E. Makarchenko.

Egg. Elongate oval ( Fig. 40 ), length 340‒379 µm, width near equator 256‒260 µm (n=4); the anterior pole is narrower than the posterior pole, and tapering smoothly beyond the equator to a broadly rounded tip ( Fig. 40 ). Collar nipple-shaped and set on a thickened subapical plate resembling a ring-shaped chorionic fold; at the collar base there is an additional thin rim surrounded by small pits ( Figs. 41‒42 ). Anchor is roughly umbrella-shaped ( Fig. 40 ), but it was not possible to determine the shape more precisely since the eggs were linked together by anchor plates that could not be separated without destroying them. The chorion surface is irregularly granular, with shallow hexagonal FCIs and shallow punctuation within the cells ( Figs. 40, 42‒43 ). The area between the micropylar line and the anterior pole is almost smooth with hexagonal FCIs but without punctuation, occupying about 1/3 of the egg length ( Figs. 40, 42‒44 ). Micropyles are located in a subequatorial position near the anterior pole ( Figs. 40, 42‒43 ); the sperm guides are distinct, medium-length, tunnel-shaped, and located obliquely to the chorion axis; orifices are oval, sessile, small, and slightly raised above the chorionic surface ( Figs. 40‒44 ).

Comments. The egg of A. brevipennis was first briefly described by Zwick (1984), then by Sivec et al. (2005), with comments on size and shape. Our supplementary description agrees with the original description of these features.

Distribution. East Palaearctic species that is widespread from the Altai, Sayan Mountains, through Mongolia and China ( Zhu et al. 2006) to the Russian Far East, including Sakhalin Island and the south of the Magadan Oblast. The report of A. brevipennis in Poland in Plecoptera Species File ( DeWalt et al. 2023) requires confirmation.

Figures

FIGURES 40–44. Agnetina brevipennis (Navás, 1912). Russia, Far East, Yakutia, Chulman River, above Neryungri town, Lena River basin. Egg, cleaned. 40. Habitus with several anchors glued together, lateral. 41. Collar with a thickened subapical plate, dorsolateral. 42. Habitus, collar, subapical plate, chorion structure, micropylar row, lateral. 43. The chorion structure in the micropylar line area, lateral. 44. Orifices and the sperm guides, lateral.