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Molecular systematics, biogeography and population structure of Neotropical freshwater needlefishes of the genus Potamorrhaphis
Author(s) -
Lovejoy N. R.,
De Araújo M. L. G.
Publication year - 2000
Publication title -
molecular ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.619
H-Index - 225
eISSN - 1365-294X
pISSN - 0962-1083
DOI - 10.1046/j.1365-294x.2000.00845.x
Subject(s) - biology , biological dispersal , clade , biogeography , monophyly , amazon rainforest , ecology , genus , gene flow , phylogenetic tree , systematics , phylogeography , population , zoology , taxonomy (biology) , genetic variation , biochemistry , demography , sociology , gene
Phylogenetic relationships of populations and species within Potamorrhaphis , a genus of freshwater South American needlefishes, were assessed using mitochondrial cytochrome b sequences. Samples were obtained from eight widely distributed localities in the Amazon and Orinoco rivers, and represented all three currently recognized species of Potamorrhaphis . The phylogeny of haplotypes corresponded imperfectly to current morphological species identities: haplotypes from P. guianensis , the most widespread species, did not make up a monophyletic clade. Geography played a strong role in structuring genetic variation: no haplotypes were shared between any localities, indicating restricted gene flow. Possible causes of this pattern include limited dispersal and the effects of current and past geographical barriers. The haplotype phylogeny also showed a complex relationship between fishes from different river basins. Based on the geographical distribution of clades, we hypothesize a connection between the middle Orinoco and Amazon via rivers of the Guianas. More ancient divergence events may have resulted from Miocene alterations of river drainage patterns. We also present limited data for two other Neotropical freshwater needlefish genera: Belonion and Pseudotylosurus . Pseudotylosurus showed evidence of substantial gene flow between distant localities, indicating ecological differences from Potamorrhaphis .