Neoperla (Formosita) Klapálek, 1914

Zwick, Peter, 2023, A new classification of genus Neoperla and systematic studies of other Perlinae (Plecoptera: Perlidae), Zootaxa 5339 (2), pp. 101-131 : 111-112

2.4.2.2. Neoperla (Formosita) Klapálek, 1914 , new status

Formosina Klapálek, 1913: 117 ; preoccupied (Becker, 1911, Diptera ), no type species designated. Preoccupied.

Formosita Klapálek, 1914: 118 ; replacement name, again no type species designated. Secondary designation of Neoperla costalis Klapálek, 1913 , as type species: Zwick (2016).

Wu (1938) included the name Formosita in a key but placed no species in the genus. However, he illustrated and described as Neoperla several species that fit the diagnosis of Formosita . Numerous Asian males have no unpaired median process on T7 but some other modification of the caudal area of T7, the diversity of structures and shapes is high. T8 is much less variable, mostly it bears a forward-curved process.

The modifications of T7 are manyfold. There may be a sclerotized median band connected to some moderate caudal swelling with a few sharp granules (like in the N. costalis lectotype ( Sivec & Zwick 1988)), or T7 may have a large spinose hump or other modifications like paired processes in the front of T7 which reach over a strong caudal swelling behind them; selected samples of the diversity in subgenus Formosita are presented below.

Many Asian species share a chorion structure which occurs only among Asian Neoperla , not in Neoperla on other continents nor in any other Plecoptera : the chorion is covered by numerous straight rows of densely placed punctures in, e. g., N. obliqua Banks, 1913 and other Philippine species ( Sivec 1984). Near the poles the puncture rows fade away or are connected to cells at the base of operculum or collar. In many species the rows converge in groups of three which I call triplets. Long and short triplets alternate, micropyles stand always in the median row of a triplet, the ~3µm wide micropyle orifice interrupts the puncture row and by transparency the micropylar canal is visible in the empty space.

Triplets seem to be apomorphic, they occur in several subgroups of Neoperla (Formosita) ( Table 1 ). Knowledge of this detail is too scanty to base taxonomic decisions on it. Triplets are possibly a further development of many straight puncture rows on the chorion like a number of Philippine species have ( Sivec 1984). Some of these also have a flat polar disc without anchor but with a central knob or projection surrounded by many spherical adhesive bodies. A great diversity of anchors has been documented (e.g., Isobe 1997), apparently there is no groundplan pattern of the anchor but the follicular membrane is able to form multiple kinds of attachment structures. Close agreement in attachment pattern supports groups of low taxonomic rank.