Phanoperla nana Zwick, 1982

Mason, Denise & Stark, Bill P., 2015, Notes On The Genus Phanoperla Banks From Sri Lanka And India (Plecoptera: Perlidae), Illiesia 11 (4), pp. 29-40 : 32

Phanoperla nana Zwick

( Figs. 7-12 )

Phanoperla nana Zwick 1982a:100 . Holotype ♂ ( Naturhistorisches Museum , Wien), Peradeniya, [Central Province, Kandy District], Ceylon [ Sri Lanka]

Material examined. SRI LANKA: Matale District , Kibissa, 0.5 miles W Sigiriya Jungle, 28 June-4 July 1978, K. V . Krombein, P.B. Karunaratne, T . Wijesinhe, V . Kulasekare, 1♀ ( USNM). Ratnapura District , Uggalkaltota, 23-26 June 1978, K. V . Krombein, P.B. Karunaratne, T . Wijesinhe, L. Jayawickrema, N. Karanaratne, 3♂, 8♀ ( USNM) .

Egg. Outline oval with broadly rounded anterior pole ( Fig. 7 ). Length ca. 318-330 μm, equatorial width ca. 230-240 μm. Collar ca. 18-22 μm long and ca. 55-63 μm wide, margin slightly flanged and irregularly incised, sides covered with two rows of irregular meshes ( Figs. 9, 11 ). Globular anchor subtended by a ring of grape-like clusters of small globular bodies and supported on a long, slender pedicel ( Fig. 11 ). Chorion with shallow, obscure pits over entire surface ( Figs. 9-10 ); follicle cell impressions enclose pits in the chorionic zone adjacent to the collar ( Fig. 8 ), but are not evident over most of surface. Micropyles with slanted, almost circular orifices, without elongate sperm guides ( Fig. 12 ); micropylar row subequatorial.

Comments. The anchor on the eggs of these specimens is consistent with that of P. nana (compare Fig. 11 with Fig. 8e in Zwick 1982a) and the female is small, has widely separated ocelli, and the subgenital plate is undeveloped. Zwick’s (1982a) comment on the P. nana egg chorion indicates the surface is “…very finely and densely punctate…” and in the egg image presented ( Fig. 8e ) there are no follicle cell impressions shown or mentioned in the description. Our figures show a small zone of follicle cell impressions surrounding the collar ( Figs. 8-9 ), and a surface that is covered throughout with obscure pits. Consequently, these specimens might represent an undescribed sibling species in the P. nana -group, but because the aedeagus of males associated with the females at the Uggalkaltota site are consistent with the descriptions of P. nana provided by Zwick (1982a), we accept these females as the probable females of P. nana .

Figures

Figs. 7-12. Putative Phanoperla nana egg. 7. Lateral aspect. 8. Collar end. 9. Chorionic detail surrounding collar. 10. Lid and micropylar zone. 11. Collar and anchor. 12. Micropyles.