Editorial Type:
Article Category: Research Article
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Online Publication Date: 01 Aug 2001

Phylogenetic Relationships of Cyprinid Fishes in Subgenus Notropis Inferred from Nucleotide Sequences of the Mitochondrially Encoded Cytochrome b Gene

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Page Range: 656 – 667
DOI: 10.1643/0045-8511(2001)001[0656:PROCFI]2.0.CO;2
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Abstract

Cytochrome b sequences (1140 bp) from 16 species considered to be members of subgenus Notropis and several outgroup taxa were analyzed phylogenetically. Phylogenetic analysis of cytochrome b was sensitive to sampling of outgroup taxa, probably resulting from substitutional rate heterogeneity among outgroups. Maximum-likelihood analysis was more robust to these effects as compared to maximum parsimony. Both maximum parsimony and maximum-likelihood analysis supported removal of Notropis candidus and Notropis shumardi from subgenus Notropis. Monophyly of the 14 remaining species was supported by the maximum likelihood analysis. Regardless of the method of analysis or use of outgroup taxa, phylogenetic analysis of cytochrome b indicated strong support for the following hypothesis of relationships: ((Notropis rubellus, Notropis suttkusi), (Notropis amoenus, Notropis stilbius, ((Notropis atherinoides, Notropis oxyrhynchus), (Notropis amabilis, Notropis jemezanus)))). This phylogenetic hypothesis implies that morphological characters associated with increased olfaction were derived independently among members of subgenus Notropis, perhaps in response to life in more turbid habitats.

Copyright: The American Society of Ichthyologists and Herpetologists
 Fig. 1. 
 Fig. 1. 

Single most-parsimonious tree (1676 steps) derived from maximum-parsimony analysis of complete cyt b sequences (CI = 0.34; RI = 0.37). Numbers above nodes represent nonparametric bootstrap proportions (1000 replications). Bootstrap proportions less than 50% are not shown. Asterisks (*) indicate hypothesized members of subgenus Notropis

 Fig. 2. 
 Fig. 2. 

Optimal topology (−lnL = 8016.3) recovered from maximum-likelihood analysis of cyt b sequences, using the GTR substitution matrix combined with a correction for invariant sites. Numbers above nodes are bootstrap proportions (100 replications). Bootstrap proportions less than 50% are not shown. Asterisks (*) indicate hypothesized members of subgenus Notropis

 Fig. 3. 
 Fig. 3. 

Strict consensus of six equally parsimonious trees (857 steps) derived from maximum-parsimony analysis of cyt b sequences of 14 species of subgenus Notropis (CI = 0.50; RI = 0.38). Numbers above nodes represent nonparametric bootstrap proportions (1000 replications). Bootstrap proportions less than 50% are not shown. Location of the root was inferred a posteriori to tree selection

 Fig. 4. 
 Fig. 4. 

Optimal topology (−lnL = 5037.5) recovered from maximum-likelihood analysis of cyt b sequences of 14 species of subgenus Notropis. The model used was the GTR matrix combined with a correction for invariant sites. Numbers above nodes represent bootstrap proportions (100 replications). Bootstrap proportions less than 50% are not presented. Location of the root was inferred a posteriori to tree selection

Accepted: 23 Jan 2001
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