Position and definition of the genus Paegniodes Eaton, 1881 based on redescription on the type species Paegniodes cupulatus (Eaton, 1871) (Ephemeroptera: Heptageniidae)

First record of Paegniodes Eaton, 1881 (Ephemeroptera, Heptageniidae) from Thailand with description of a new species

“…The findings of this study revealed that the common characters in adults of Paegniodes were an abdomen with median and a pair of oblique stripes in both male and female subimagoes, as also found in P. cupulatus and P. dao (Nguyen and Bae 2004;Ma et al 2018). Additionally, the unique egg chorionic structure of Paegniodes includes hexagonal mesh ridges and 1-4 knobs between them (Ma et al 2018). Unlike the relatively similar Rhithrogeniella (subfamily Ecdyonurinae), only one KCT is found between the ridges (Kang and Yang 1994;Sartori 2014).…”

“…nov. which seem darker than that of P. cupulatus. On the abdominal terga of P. cupulatus, the pale dots are on both side of median stripe (Ma et al 2018: fig. 1A), while pale dots of the new species are inside the median stripe (Fig.…”

“…The combination characteristics of Paegniodes that distinguish it from all other genera in the subfamily Rhithrogeninae include: i) reduced lamellae on the gills I, ii) caudal filaments with interfacing setae, iii) short hindwings (usually less than 1/4 the length of the forewings), and iv) males having widely separated penes with strongly median titillators (Nguyen and Bae 2004;Webb and McCafferty 2008;Ma et al 2018). The findings of this study revealed that the common characters in adults of Paegniodes were an abdomen with median and a pair of oblique stripes in both male and female subimagoes, as also found in P. cupulatus and P. dao (Nguyen and Bae 2004;Ma et al 2018). Additionally, the unique egg chorionic structure of Paegniodes includes hexagonal mesh ridges and 1-4 knobs between them (Ma et al 2018).…”

“…The poorly known mayfly genus Paegniodes, established by Eaton (1881), currently comprises two valid species: P. cupulatus (Eaton, 1871) from China (Ma et al 2018; adults, larva, and egg) and P. dao Nguyen & Bae, 2004 from Vietnam (Nguyen and Bae 2004;larva only). Based on the unique characters of the imaginal and larval stages, Ma et al (2018) clearly confirmed the generic status of Paegniodes, following Webb and McCafferty (2008). In addition, the complete mitochondrial genome of P. cupulatus was provided by Zhou et al (2014).…”

Comparative Mitogenomic Analysis of Heptageniid Mayflies (Insecta: Ephemeroptera): Conserved Intergenic Spacer and tRNA Gene Duplication

“…The absence of the trnM duplication of P. cupulatus seems to support this phylogenetic relationship. Additionally, our previous study found that the genus Paegniodes possessed more plesiomorphies in Heptageniidae, such as terminal filament and cerci well-developed, setae scattered on the ventral surface of the maxillae, and gills not enlarged or not forming a friction disk [ 58 ]. On the basis of the above analyses, P. cupulatus might be recognized as the earliest diverging species among the analyzed heptageniids.…”