A New Species of Vietnamella Tshernova 1972 (Ephemeroptera: Vietnamellidae) from Thailand

Abstract

The larva, male subimago, female imago, and eggs of V. nanensis sp. n. are described based on specimens from Mae Hong Son and Nan provinces, Thailand. The female subimago is described based on a photograph of a specimen reared to the imago stage. The species previously was distinguished only by DNA barcode data and designated as Vietnamella sp. C. Based on morphology, the larva of the new species can be distinguished with the following combination of characteristics: (i) pattern of serration on the ventral margin of the forefemur, (ii) posterolateral margins of abdominal terga with pairs of acute tubercles, especially terga VI and VII, (iii) a well-developed pair of median ridge projections on tergum X, (iv) the second segment of the maxillary palp being about 1.3× the length of the third segment, and (v) females containing eggs with prominent protuberances on the chorionic surface. A key to larvae of all known species in the genus is provided.

Cryptic Species Exist in Vietnamella sinensis Hsu, 1936 (Insecta: Ephemeroptera) from Studies of Complete Mitochondrial Genomes

“…In 2017, Hu et al described V. dabieshanensis You and Su, 1987, V. qingyuanensis Zhou and Su, 1995, and V. guadunensis Zhou and Su, 1995 as junior synonyms of V. sinensis Hsu, 1936 [ 37 ]. As of 2021, there are six valid described Vietnamella species including V. thani Tshernova, 1972, V. ornata Tshernova, 1972, V. sinensis , V. maculosa Auychinda et al, 2020, V. nanensis Auchyinda et al, 2020, and V. chebalingensis Tong, 2020 [ 32 , 38 , 39 , 40 ].…”