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.
Freshwater red algae of the order Batrachospermales are poorly studied in India and Nepal, especially on a molecular basis. During a survey in northeast India and east Nepal, six populations of the genus Sheathia were found and analyzed using molecular and morphological evidence. Phylogenetic analyses based on the rbcL gene sequences grouped all populations in a large clade including our S. arcuata specimens and others from several regions. Sheathia arcuata represents a species complex with a high sequence divergence and several smaller clades. Samples from India and Nepal were grouped in three distinct clades with high support and representing new cryptic species: a clade formed by two samples from India, which was named Sheathia assamica sp. nov.; one sample from India and one from Nepal formed another clade, named Sheathia indonepalensis sp. nov.; two samples from Nepal grouped with sequences from Hawaii and Indonesia (only 'Chantransia' stages) and gametophytes from Taiwan, named Sheathia dispersa sp. nov. Morphological characters of the specimens from these three species overlap one another and with the general circumscription of S. arcuata, which lacks the heterocortication (presence of bulbous cells in the cortical filaments) present in other species of the genus Sheathia. Although the region sampled is relatively restricted, the genetic diversity among specimens of these three groups was high and not closely related in the phylogenetic relationship with the other clades of S. arcuata. These data corroborate information from other groups of organisms (e.g., land and aquatic plants) that indicates this region (Eastern Himalaya) as a hotspot of biodiversity.
This study evaluated the species level taxonomy and phylogenetic relationships among species of the section Setacea of the genus Batrachospermum. Molecular data (sequences of the plastid-encoded RuBisCO large subunit gene, rbcL; and the barcode region of the mitochondrial gene that encodes the cytochrome c oxidase subunit 1, cox1) were generated and morphological characters described for 15 populations from Brazil, Japan and Spain. The analyses of rbcL sequences revealed that section Setacea forms a well-supported clade, which was positioned close but clearly separated from some species of Batrachospermum usually called group 'Australasica'. Three well-supported clades were formed within the section: Batrachospermum sp. from Brazil; Batrachospermum atrum from Australasia, Europe and Asia and Batrachospermum puiggarianum from South America. The analyses of cox1 sequences revealed two well-supported groups: a large group with the sequences of B. puiggarianum from Brazil and a small group with one sequence of B. atrum from Spain and two sequences of Batrachospermum sp. from Brazil. The interspecific variation among these three species was high (38-71 bp, 3.0-5.5% for rbcL; 37-51 bp, 5.6-7.5% for cox1); whereas, sequence divergences within these three clades were much lower (0-33 bp, 0-2.6% for rbcL; 0-15 bp, 0-2.3% for cox1). The section is raised to genus (Setacea), and three species were recognized, including two previously described species (Setacea atra and Setacea puiggariana) that can be separated by either molecular and morphological data. A third species could not be distinguished from S. atra by morphological evidence but is clearly distinct based on divergence levels of both molecular markers used in this study (5.6-6.2% for rbcL; 3.0-3.4% for cox1) and is proposed as a new species (Setacea atro-brasiliensis) with the known geographic distribution restricted to Brazil.
In India the genus Sirodotia has been documented solely on morphological data. A new species of Sirodotia (Sirodotia assamica sp. nov.) was found in two localities in the State of Assam, India. Phylogenetic relationships of the new species were inferred on the basis of DNA sequence data for the plastid rbcL gene and the barcode region of the mitochondrial COI-5P gene. Taxonomic affinities of the new species were determined by morphological analyses and a distinctive character was found for this species: spermatangia arranged in clusters. Although this character is also observed in S. huillensis, both species are genetically highly divergent (4.5–5.0% for rbcL and 9.6–10.1% for COI-5P). DNA sequences from Indian specimens formed a well-supported clade, sister to S. delicatula from Malaysia. DNA sequence divergence between S. assamica and S. delicatula varied from 2.5–2.7% for rbcL and COI-5P. Intraspecific divergence between the two sequences from India were low (0.4–0.5%). A full description and photographs of the new species are provided, as well as a comparison with morphologically similar and phylogenetically allied species reported from India and other Asian regions.
do Campo Alegre, s/n, 4169-007 Porto (Portugal) couverture / cover : Extraits d'éléments de la Figure 6 / Extracts of the Figure 6 Cryptogamie, Algologie est indexé dans / Cryptogamie, Algologie
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.