Potamyia Banks 1900

Zhang, Ao & Zhou, Xin, 2021, The larvae of Chinese Hydropsychidae (Insecta: Trichoptera), Part II: Potamyia chinensis and Cheumatopsyche trifascia, Zootaxa 4926 (4), pp. 547-558 : 548-551

GENUS Potamyia Banks 1900

A total of 10 Potamyia species have been recorded from China ( Yang et al. 2016). Of these, three species were collected during 2004 and 2005 from southern China. In the present study, the larva of P. chinensis ( Ulmer 1915) is associated with adults using independent DNA sequences ( Table 1; Fig. 1 ), which enables the first report on larval morphology for the species distributed in China. The low association number of species in the genus is mainly due to the fact that Potamyia are mostly inhabitants of large rivers, such as the North American species P. flava (Hagen) ( Wiggins 1996) , which presents an obvious challenge for larval collection. Only one larval specimen was collected during the course of this study.

The species associated here, P. chinensis ( Ulmer 1915) is a senior synonym of Hydropsyche echigoensis Tsuda 1949 ( Oláh et al. 2006, 2008) and Cheumatopsyche tienmuiaca Schmid 1965 ( Tian et al. 1996; Oláh et al. 2006, 2008). The larva of P. chinensis has been described from Japan ( Tanida 2005); we provide here a redescription of the larva of the species based on our Chinese material.

Generic characteristics of the genus. Although only one Chinese larval specimen is available at the time of the study, descriptions and illustrations are available for P. flava from North America ( Ross 1944, 1959; Wiggins 1996) and for P. chinensis from Japan ( Tanida 2005). A few characteristics seem to be consistently diagnostic for the genus: Front margin of frontoclypeal apotome complete and symmetrical; primary setae and some secondary setae on head long and thin; front margin of submentum cleft, anterior borders of two small submental lobes oblique and straight; anterior border of anterior ventral apotome short and protrusive in middle (not obvious in P. chinensis described from Japan); anterior ventral apotome shorter than sub-mentum; foretrochantin not forked at least in some individuals [a series of intermediates ranging from unforked to forked have been observed in P. flava ( Wiggins 1996) ]; prosternal plate large, followed by pair of small posterior prosternal sclerites; pair of ventral tracheal gills present on abdominal segment VII, each with single gill stem.

Figures

FIGURE 1. Larval-adult association of Chinese Potamyia and Cheumatopsyche species. 1a, COI Maximum Likelihood phylogram; 1b, D2 Maximum Likelihood phylogram. L = larva; M = adult male. Bootstraps values are shown below stems; values less than 75 are not shown in the phylograms.