Phylogeny and morphology of the freshwater red alga Nemalionopsis shawii (Rhodophyta, Thoreales) from Nepal

Abstract

Phylogenetic relationships and morphological characters are presented for a population of Nemalionopsis shawii Skuja collected from Nepal. Molecular data (sequences of rbcL and cox1) were generated and morphological characters were described in detail. The rbcL sequence analyses showed that specimens from Nepal are most similar to N. shawii from Indonesia and Japan and that these entities form a clade with high support (>95% bootstrap and 0.95 posterior probability). The cox1 barcode sequence, however, only had 90.9-91.9% identity with specimens of N. shawii from Hawaii. The rbcL sequence of the specimen from Nepal was positioned in a clade having sequence identity of 99.3-99.7% with three samples: N. shawii from Indonesia and two from Japan identified as N. tortuosa. The comparison of morphological characters of Nemalionopsis from Nepal allowed unequivocal identification with N. shawii. Identifications from previous studies using molecular data were mistaken since most reports of N. shawii are actually of N. tortuosa or vice-versa. This confusion of names presumably occurred because most specimens previously sequenced were from culture collections or from 'Chantransia' stages. Small tufts of 'Chantransia' stage were observed growing epiphytically on gametophytes and on the basal system. Carpogonia and spermatangia were fully described in specimens from Nepal. Monosporangia were not observed, whereas carposporangia were unequivocally described for the first time in the genus. An unusual flat strap-like basal system was observed, interpreted as an additional mode of maintenance in nature under unfavorable environmental conditions.

Three gene phylogeny of the Thoreales (Rhodophyta) reveals high species diversity

“…However, the measurements from specimens in Nepal (NP) in Necchi et al. () were somewhat larger. All cells (except the cylindrical base cell) within the assimilatory filaments were also distinctly barrel‐shaped (Fig.…”

“…For seven specimens from the analysis, morphological traits could be examined for both qualitative and quantitative characters. As well, both DNA sequence and morphological data for Nemalionopsis shawii and Thorea indica were available from the literature (Necchi et al 2015(Necchi et al , 2016. In addition, two permanent slides of T. violacea, holotype and isotype, and two historically important specimens of T. hispida were examined from the Mus eum National d'toire Naturelle (PC; Thiers 2017).…”

“…, Necchi et al. ). In addition to tropical, and subtropical regions, there are records of Thorea in temperate areas.…”

“…Two new species, Thorea siamensis from Thailand and T. indica from subtropical India, have been recently proposed (Traichaiyaporn et al 2008, Necchi et al 2015. Nemalionopsis has been reported from Taiwan (N. tortuosa) and Nepal (N. shawii; Chou et al 2014, Necchi et al 2016. In addition to tropical, and subtropical regions, there are records of Thorea in temperate areas.…”

Algal flora of Rajarani Lake, Dhankuta and their seasonal distribution

“…Algae of Nepal has been studied by Hirano (1984), Bando et al (1989), Watanabe (1995), Watanabe and Komarek (1988), Komarek and Watanabe (1998), Jüttner et al (2003), , Misra (2010, 2012), Jha and Kargupta (2012), Rai (2013Rai ( , 2014, Necchi et al (2016) etc. Algal flora of Rajarani lake, Dhankuta has not been studied yet and it is the preliminary work for this area.…”