Phylogenetic Assessment of Freshwater Mussels Castalia ambigua and C. inflata at an Ecotone in the Paraguay River Basin, Brazil Shows That Inflated and Compressed Shell Morphotypes Are the Same Species

Miluska Olivera-Hyde; Eric Hallerman; Rogério Santos; Jess Jones; Brianne Varnerin; Guilherme da Cruz Santos Neto; Maria Cristina Mansur; Priscilla Moraleco; Claudia Callil

doi:10.3390/d12120481

Diversity (Dec 2020)

Phylogenetic Assessment of Freshwater Mussels Castalia ambigua and C. inflata at an Ecotone in the Paraguay River Basin, Brazil Shows That Inflated and Compressed Shell Morphotypes Are the Same Species

Miluska Olivera-Hyde,
Eric Hallerman,
Rogério Santos,
Jess Jones,
Brianne Varnerin,
Guilherme da Cruz Santos Neto,
Maria Cristina Mansur,
Priscilla Moraleco,
Claudia Callil

Affiliations

Miluska Olivera-Hyde: Department of Fish and Wildlife Conservation, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
Eric Hallerman: Department of Fish and Wildlife Conservation, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
Rogério Santos: ECOBIV—Conservation and Ecology of Freshwater Mussel Group, Bioscience Institute of Federal University of Mato Grosso—UFMT, Av. Fernando Correa da Costa 2367, Cuiabá 78060-900, MT, Brazil
Jess Jones: Department of Fish and Wildlife Conservation, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
Brianne Varnerin: Department of Fish and Wildlife Conservation, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
Guilherme da Cruz Santos Neto: Laboratory of Molecular Biology and Neuroecology, Federal Institute of Para—Braganza Campus, Av. dos Bragancanos S/N, Bairro Vila Sinha, Braganca CEP 68600-000, PA, Brazil
Maria Cristina Mansur: ECOBIV—Conservation and Ecology of Freshwater Mussel Group, Bioscience Institute of Federal University of Mato Grosso—UFMT, Av. Fernando Correa da Costa 2367, Cuiabá 78060-900, MT, Brazil
Priscilla Moraleco: ECOBIV—Conservation and Ecology of Freshwater Mussel Group, Bioscience Institute of Federal University of Mato Grosso—UFMT, Av. Fernando Correa da Costa 2367, Cuiabá 78060-900, MT, Brazil
Claudia Callil: ECOBIV—Conservation and Ecology of Freshwater Mussel Group, Bioscience Institute of Federal University of Mato Grosso—UFMT, Av. Fernando Correa da Costa 2367, Cuiabá 78060-900, MT, Brazil

DOI: https://doi.org/10.3390/d12120481
Journal volume & issue: Vol. 12, no. 12
p. 481

Abstract

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The phylogeny and taxonomy of freshwater mussels of the genus Castalia in South America is complicated by issues of morphological plasticity and limited molecular genetic data. We present field data on the distributions of the nominal Castalia ambigua and C. inflata in the upper Paraguay River basin in Brazil based on original occurrence data at 23 sample sites and on historical records. The upper basin has distinct highland and lowland regions, the latter including the Pantanal wetland, where “C. ambigua” occurs in the highlands and “C. inflata” occurs in both regions. At Baixo Stream in the highlands, we observed individuals with shell morphologies of either C. ambigua or C. inflata, and also individuals with intermediate shell morphology. DNA sequence variation in the upland Baixo Stream and two representative lowland populations were screened. Two mitochondrial and three nuclear genes were sequenced to test hypotheses regarding the number of species-level phylogenetic lineages present. Reported individual DNA sequences from Amazon-basin C. ambigua and other Castalia and outgroup species were included in the analysis as outgroups. Individuals from the Paraguay River basin exhibited 17 haplotypes at the mitochondrial cytochrome oxidase I (COI) gene and nine at mitochondrial 16S rRNA. Analysis of haplotype networks and phylogenetic trees of combined COI + 16S rRNA sequences among individuals with the respective shell morphologies supported the hypothesis that C. ambigua and C. inflata from the Paraguay River basin belong to the same species and one phylogenetic lineage. No variation was observed at the nuclear 18S rRNA internal transcribed spacer, 28S rRNA, or H3NR histone genes among individuals used in this study. Across all markers, less variation was observed among Paraguay basin populations than between Paraguay and Amazon basin populations. Our results collectively suggest that: (1) “C. ambigua”, “C. inflata”, and morphologically intermediate individuals within the upper Paraguay drainage represent one phylogenetic lineage, (2) a phylogeographic divide exists between Castalia populations occurring in the Paraguay and Amazon River basins, and (3) the evolutionary and taxonomic uncertainties that we have identified among Castalia species should be thoroughly assessed across their distribution using both morphological and molecular characters.

Published in Diversity

ISSN: 1424-2818 (Online)
Publisher: MDPI AG
Country of publisher: Switzerland
LCC subjects: Science: Biology (General)
Website: http://www.mdpi.com/journal/diversity/

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