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Johansen JR, González-Resendiz L, Escobar-Sánchez V, Segal-Kischinevzky C, Martínez-Yerena J, Hernández-Sánchez J, Hernández-Pérez G, León-Tejera H. When will taxonomic saturation be achieved? A case study in Nunduva and Kyrtuthrix (Rivulariaceae, Cyanobacteria). J Phycol 2021; 57:1699-1720. [PMID: 34289115 DOI: 10.1111/jpy.13201] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 05/12/2021] [Accepted: 06/08/2021] [Indexed: 06/13/2023]
Abstract
A number of heterocytous, mat-forming, tapering cyanobacteria in Rivulariaceae have recently been observed in both the Atlantic and Pacific coasts in the rocky intertidal and supratidal zones. These belong to the genera Nunduva, Kyrtuthrix, and Phyllonema and have been the subject of several recent studies. Herein, two new species of Nunduva (N. komarkovae and N. sanagustinensis) and two new species of Kyrtuthrix (K. munecosensis and K. totonaca) are characterized and described from the coasts of Mexico. Genetic separation based on the 16S-23S ITS region was pronounced (>10% in all comparisons). Morphological differences between all existing species in these two genera were also observed, but the group is morphologically complex, and these taxa are considered pseudocryptic. Nunduva and Kyrtuthrix remain morphologically and phylogenetically separate even with the addition of new species. However, how long will this remain the case? Many new genera and species of cyanobacteria have recently been described. Will the taxonomy of cyanobacteria eventually become saturated? Will we start to see multiple populations for the same cryptic species, or will future taxonomists collapse multiple species into fewer species, or multiple genera into single genera. The description of even more Nunduva and Kyrtuthrix species causes us to pause and evaluate the future of cyanobacterial taxonomy. These same questions are faced by algal taxonomists studying other phyla, and the resolution may ultimately be similar.
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Affiliation(s)
- Jeffrey R Johansen
- Department of Biology, John Carroll University, University Heights, Ohio, 44118, USA
- Department of Botany, University of South Bohemia, Branišovská 1760, Česke Budějovice, 370 05, Czech Republic
| | - Laura González-Resendiz
- Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana- Cuajimalpa, Av. Vasco de Quiroga 4871, Ciudad de México, C.P. 053000, Mexico
| | - Viviana Escobar-Sánchez
- Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México (UNAM), Coyoacán, Código Postal, Ciudad de México, 04510, Mexico
| | - Claudia Segal-Kischinevzky
- Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México (UNAM), Coyoacán, Código Postal, Ciudad de México, 04510, Mexico
| | - José Martínez-Yerena
- Departamento de Biología Comparada, Facultad de Ciencias, Universidad Nacional Autónoma de México (UNAM), Coyoacán, Código Postal, Ciudad de México, 04510, Mexico
| | - Joaquín Hernández-Sánchez
- Departamento de Biología Comparada, Facultad de Ciencias, Universidad Nacional Autónoma de México (UNAM), Coyoacán, Código Postal, Ciudad de México, 04510, Mexico
| | - Gabriela Hernández-Pérez
- Departamento de Biología Comparada, Facultad de Ciencias, Universidad Nacional Autónoma de México (UNAM), Coyoacán, Código Postal, Ciudad de México, 04510, Mexico
| | - Hilda León-Tejera
- Departamento de Biología Comparada, Facultad de Ciencias, Universidad Nacional Autónoma de México (UNAM), Coyoacán, Código Postal, Ciudad de México, 04510, Mexico
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González-Resendiz L, Johansen JR, León-Tejera H, Sánchez L, Segal-Kischinevzky C, Escobar-Sánchez V, Morales M. A bridge too far in naming species: a total evidence approach does not support recognition of four species in Desertifilum (Cyanobacteria). J Phycol 2019; 55:898-911. [PMID: 31012104 DOI: 10.1111/jpy.12867] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 04/05/2019] [Indexed: 06/09/2023]
Abstract
A population of Desertifilum (Cyanobacteria, Oscillatoriales) from an oligotrophic desertic biotope was isolated and characterized using a polyphasic approach including molecular, morphological, and ecological information. The population was initially assumed to be a new species based on ecological and biogeographic separation from other existing species, however, phylogenetic analyses based on sequences of the 16S rRNA gene and 16S-23S ITS region, placed this strain clearly within the type species, Desertifilum tharense. Comparative analysis of morphology, 16S rRNA gene similarity, 16S-23S ITS secondary structure, and percent dissimilarity of the ITS regions for all characterized strains supports placing the six Desertifilum strains (designated as PD2001/TDC17, UAM-C/S02, CHAB7200, NapGTcm17, IPPAS B-1220, and PMC 872.14) into D. tharense. The recognition of Desertifilum salkalinema and Desertifilum dzianense is not supported, although our analysis does support continued recognition of Desertifilum fontinale. Pragmatic criteria for recognition of closely related species are proposed based on this study and others, and more rigorous review of future taxonomic papers is recommended.
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Affiliation(s)
- Laura González-Resendiz
- Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana-Cuajimalpa, Cuajimalpa, Av. Vasco de Quiroga 4871, C.P. 05300, Ciudad de México, México
| | - Jeffrey R Johansen
- Department of Biology, John Carroll University, University Heights, Ohio, 44118, USA
- Department of Botany, Faculty of Science, University of South Bohemia, Branišovská 31, České Budějovice, 370 05, Czech Republic
| | - Hilda León-Tejera
- Departamento de Biología Comparada, Facultad de Ciencias, Universidad Nacional Autónoma de México (UNAM), Ciudad de México, México
| | - León Sánchez
- Doctorado en Biotecnología, Universidad Autónoma Metropolitana-Iztapalapa, México, México
| | - Claudia Segal-Kischinevzky
- Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México (UNAM), Ciudad de México, México
| | - Viviana Escobar-Sánchez
- Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México (UNAM), Ciudad de México, México
| | - Marcia Morales
- Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana-Cuajimalpa, Cuajimalpa, Av. Vasco de Quiroga 4871, C.P. 05300, Ciudad de México, México
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González-Resendiz L, Johansen JR, Escobar-Sánchez V, Segal-Kischinevzky C, Jiménez-García LF, León-Tejera H. Two new species of Phyllonema (Rivulariaceae, Cyanobacteria) with an emendation of the genus. J Phycol 2018; 54:638-652. [PMID: 30055049 DOI: 10.1111/jpy.12769] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 06/15/2018] [Indexed: 06/08/2023]
Abstract
Two untapered, heterocytous species were observed and collected from the intertidal and supratidal zones of the Mexican coastline of the Pacific Ocean near Oaxaca and from the Gulf of Mexico. These populations were highly similar in morphology to the freshwater taxon Petalonema incrustans in the Scytonemataceae. However, 16S rRNA sequence data and phylogenetic analysis indicated that they were sister taxa to the epiphyllic, Brazilian species Phyllonema aveceniicola in the Rivulariaceae, described from culture material. While genetic identity between the two new species was high, they differed significantly in morphology, 16S rRNA gene sequence identity, and sequence and structure of the 16S-23S ITS region. Their morphology differed markedly from the generitype of the previously monotypic Phyllonema, which has tapered, heteropolar, single-false branched trichomes with very thin or absent sheath. The two new species, Phyllonema ansata and Phyllonema tangolundensis, described from both culture and environmental material, have untapered, isopolar, geminately false branched trichomes with thick, lamellated sheaths, differences so significant that the species would not be placed in Phyllonema without molecular corroboration. The morphological differences are so significant that a formal emendation of the genus is required. These taxa provide a challenge to algal taxonomy because the morphological differences are such that one would logically conclude that they represent different genera, but the phylogenetic evidence for including them all in the same genus is conclusive. This conclusion is counter to the current trend in algal taxonomy in which taxa with minor morphological differences have been repeatedly placed in separate genera based primarily upon DNA sequence evidence.
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Affiliation(s)
- Laura González-Resendiz
- Departamento de Biología Comparada, Facultad de Ciencias, Universidad Nacional Autónoma de México (UNAM), Coyoacán, Código Postal 04510, Ciudad de México, México
| | - Jeffrey R Johansen
- Department of Biology, John Carroll University, University Heights, Ohio, 44118, USA
- Department of Botany, University of South Bohemia, Branišovská 1760, 370 05, České Budějovice, Czech Republic
| | - Viviana Escobar-Sánchez
- Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México (UNAM), Coyoacán, Código Postal 04510, Ciudad de México, México
| | - Claudia Segal-Kischinevzky
- Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México (UNAM), Coyoacán, Código Postal 04510, Ciudad de México, México
| | - Luis F Jiménez-García
- Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México (UNAM), Coyoacán, Código Postal 04510, Ciudad de México, México
| | - Hilda León-Tejera
- Departamento de Biología Comparada, Facultad de Ciencias, Universidad Nacional Autónoma de México (UNAM), Coyoacán, Código Postal 04510, Ciudad de México, México
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León-Tejera H, Montejano G, Gold-Morgan M. Description of two interesting Scytonematacean populations from supratidal biotopes of the Mexican Pacific. ACTA ACUST UNITED AC 2005. [DOI: 10.1127/1864-1318/2005/0117-0307] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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