concept

Siluriformes

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Comparable Ages for the Independent Origins of Electrogenesis in ... journals.plos.org PLOS ONE 14 facts

claimAfrican Notopteridae and Siluriformes are passively electroreceptive, whereas Gymnotiformes and Mormyroidea independently evolved specialized electric organs for producing weak electric discharges and high-frequency tuberous electroreceptors tuned to those signals.

claimThe study supports the hypothesis that the Gymnotiformes are the sister group to the clade containing Siluriformes and Characiformes, rather than being the sister group to Siluriformes alone.

measurementThe age of the most recent common ancestor of the clade Characiphysae (Gymnotiformes, (Siluriformes, Characiformes)) is estimated at 118.9 Mya (95% CI = 107.6–130.1 Mya), and the age of the crown-group Gymnotiformes is estimated at 100.2 Mya (95% CI = 84.9–115.3 Mya) using reconstruction #1.

claimWiley and Johnson named the clade containing Gymnotiformes, Siluriformes, and Characiformes as the Characiphysae.

referenceSullivan JP, Lundberg JG, and Hardman M (2006) published 'A phylogenetic analysis of the major groups of catfishes (Teleostei : Siluriformes) using rag1 and rag2 nuclear gene sequences' in Molecular Phylogenetics and Evolution, volume 41, pages 636–662.

claimPrevious molecular studies have not recovered the Fink and Fink hypothesis of ((Gymnotiformes, Siluriformes) Characiformes).

claimThe fossil †Santanichthys diasii provided a minimum age for the most recent common ancestor of the clade (Siluriformes, Characiformes), excluding the Gymnotiformes.

claimWithin the Ostariophysi, the Siluriformes and the Gymnotiformes are the only electroreceptive fishes; the Characiformes, Cypriniformes, and Gonorynchiformes lack any form of electroreception.

claimFink and Fink (1981) proposed that the Gymnotiformes and the Siluriformes form a monophyletic group based on 22 morphological synapomorphies (shared, derived traits).

claimVarious molecular studies have reported conflicting phylogenetic topologies for the relationship between Siluriformes, Characiformes, and Gymnotiformes, or have been inconclusive.

claimThe sister group of the Gymnotiformes within the Ostariophysi is the clade consisting of Characiformes and Siluriformes, a relationship supported by bootstrap proportions ranging from 47% to 96%.

procedureThe study estimated the relative ages of stem- and crown-group gymnotiforms and mormyroids by including their putative sister groups, the Siluriformes and the Notopteridae, as well as a large sampling of basal teleost fishes.

claimWithin teleost fishes, electroreception is restricted to two distantly related groups: the Siluriphysi (Gymnotiformes plus Siluriformes) and the Notopteroidei (Mormyroidea plus Notopteridae).

claimThe ((Siluriformes, Characiformes) Gymnotiformes) topology implies that ampullary electroreceptors originated once in the Characiphysae, followed by a subsequent loss of these receptors in the characiform lineage.