Model-based total evidence phylogeny of Neotropical electric knifefishes (Teleostei, Gymnotiformes)

Abstract

This study provides the most comprehensive Model-Based Total Evidence (MBTE) phylogenetic analyses of the clade Gymnotiformes to date, reappraising relationships using a dataset comprised of six genes (5277bp) and 223 morphological characters, and an ingroup taxon sample including 120 of 212 valid species representing 34 of the 35 extant genera. Our MBTE analyses indicate the two main gymnotiform clades are Gymnotidae and Sternopygoidei, the latter comprised of Rhamphichthyoidea (Rhamphichthyidae+Hypopomidae) and Sinusoidea (Sternopygidae+Apteronotidae). Within Gymnotidae, Electrophorus and Gymnotus are sister taxa, and Gymnotus includes the following six clades: (i) G. pantherinus clade, (ii) G. coatesi clade, (iii) G. anguillaris clade, (iv) G. tigre clade, (v) G. cylindricus clade, and (vi) G. carapo clade. Within Rhamphichthyoidea, Steatogenae (Steatogenys+Hypopygus) is a member of Rhamphichthyidae, and Hypopomidae includes the following clades: (i) Akawaio, (ii) Hypopomus, (iii) Microsternarchini, and (iv) Brachyhypopomus. Within Sternopygidae, Sternopygus and Eigenmanninae are sister groups, Rhabdolichops is the sister to other Eigenmanninae, Archolaemus+Distocyclus is the sister to Eigenmannia, and Japigny is nested within Eigenmannia. Within Apteronotidae, Sternarchorhamphinae (Sternarchorhamphus+Orthosternarchus) is the sister to Apteronotinae, Adontosternarchus is the sister group to other Apteronotinae, Sternarchorhynchini (Sternarchorhynchus+Platyurosternarchus) is the sister to Navajini, and species assigned to Apteronotus are members of two separate clades: (i) A. sensu stricto in the Apteronotini, and (ii) the "A." bonapartii clade in the Navajini.

Why the short face? Developmental disintegration of the neurocranium drives convergent evolution in neotropical electric fishes

“…(a) Phylogenetic tree (based on Tagliacollo et al., 2015), trimmed to include 133 species examined for neurocranial morphology. Colored branches indicate heterocephalic variation with blue indicating more dolichocephalic and red more brachycephalic skull shapes (see inset).…”

“…Phylogeny based on Tagliacollo et al. (2015). Note multiple independent colonizations of both low (brachycephalic) and high (dolichocephalic) PC 1 scores.…”

“…This is performed by combining a previously proposed phylogeny with the scatter plots of principal components (PC) scores computed from a PCA and projecting this phylogeny onto a two‐dimensional plane where branch lengths and distances are inferred by the differences in shape between groups using squared‐changed parsimony (Sidlauskas, 2008). Treefiles were built based of the Tagliacollo, Bernt, Craig, Oliveira, & Albert (2015) phylogeny using the software Mesquite v. 2.75 (Maddison & Maddison, 2001) and imported to MorphoJ (Klingenberg, 2011) as a Nexus file using the option “map onto phylogeny.”…”

A taxonomic revision of the Neotropical electric fish genus Brachyhypopomus (Ostariophysi: Gymnotiformes: Hypopomidae), with descriptions of 15 new species

“…- Tagliacollo et al, 2016: 10 (position in phylogeny of the Gymnotiformes). -Crampton et al, 2016: 1-66, table 1, 3-4, figs.…”

Resource use by two electric fishes (Gymnotiformes) of the National Forest Saracá-Taquera, Oriximiná, Pará

“…Gymnotiforms have an elongated body, no dorsal, pelvic or adipose fins, and possess systems for electrogenesis and electrosensory that allow communication, navigation and prey location (Albert, Crampton, 2005). In headwaters streams, gymnotiforms that have pulse-type electric organ discharge (EOD), such as those belonging to the families Gymnotidae, Rhamphichthyidae, and Hypopomidae, are the most diverse (Tagliacollo et al, 2016).…”