Phylogenetic relationships among Acestrorhynchus species (Ostariophysi: Characiformes: Acestrorhynchidae)

Abstract

A total of 104 osteological and external morphological features were examined in 13 species of Acestrorhynchus and 15 outgroup taxa to advance a hypothesis of relationships within the genus. Two most parsimonious hypotheses corroborate the monophyly of Acestrorhynchus but differ in the hypothesized relationships of Acestrorhynchus heterolepis. Three proposed supraspecific assemblages are at least partially correlated with groups of species previously diagnosed on the basis of colour pattern: (1) Acestrorhynchus britskii, Acestrorhynchus grandoculis, Acestrorhynchus microlepis, and Acestrorhynchus minimus; (2) Acestrorhynchus falcirostris, Acestrorhynchus isalineae, and A. Acestrorhynchus nasutus; and (3) Acestrorhynchus abbreviatus, Acestrorhynchus altus, Acestrorhynchus falcatus, Acestrorhynchus lacustris, and Acestrorhynchus pantaneiro. In one hypothesis A. heterolepis is proposed as the closest relative of the clade formed by A. falcirostris, A. isalineae, and A. nasutus, and in the alternative hypothesis it is proposed as a sister species of the clade formed by A. abbreviatus, A. altus, A. falcatus, A. lacustris, and A. pantaneiro. Relationships among species of the latter clade remain unresolved. Two independent episodes of reduction of body size are hypothesized to have occurred within the genus: one associated with the clade formed by A. grandoculis and A. minimus, and the other with the clade formed by A. isalineae and A. nasutus.

Digenea parasites of Acestrorhynchus falcirostris (Osteichthyes, Acestrorhynchidae) in the state of Amazonas, Brazil

“…Acestrorhynchus Eigenmann & Kennedy, 1903, is a genus of the family Acestrorhynchidae that currently comprises fourteen valid species of Neotropical fish, based on Froese & Pauly (2017). These species are phylogenetically related and endemic to South America (TOLEDO-PIZA, 2007). Acestrorhynchus falcirostris is a freshwater fish that is distributed in South America: Amazon and Orinoco river basins and rivers of Guyana (FROESE & PAULY, 2017).…”

Parasite communities of the predatory fish, Acestrorhynchus falcatus and Acestrorhynchus falcirostris, living in sympatry in Brazilian Amazon

“…The species of Acestrorhynchidae are of interest because they belong to a monophyletic taxon and presented a high degree of endemism to Amazon, Orinoco, São Francisco, Paraná, Paraguay basins and La Plata drainages (SILVA & GOITEIN, 2009;TOLEDO-PIZA, 2007;PRETTI et al, 2009;FROESE & PAULY, 2016). These species are found in a variety of habitats, but primarily live in lakes in areas near the shores of the Amazon River and Orinoco River systems, and the smallest species are especially found in small creeks (igarapés).…”

“…Acestrorhynchus Eigenmann and Kennedy 1903, is the single genus of family Acestrorhynchidae Eigenmann 1912, which is formed by 15 valid species of Neotropical fish that are endemic to South America (TOLEDO-PIZA, 2007;PRETTI et al, 2009;FROESE & PAULY, 2016). The species of Acestrorhynchidae are of interest because they belong to a monophyletic taxon and presented a high degree of endemism to Amazon, Orinoco, São Francisco, Paraná, Paraguay basins and La Plata drainages (SILVA & GOITEIN, 2009;TOLEDO-PIZA, 2007;PRETTI et al, 2009;FROESE & PAULY, 2016).…”

Canais e poros do sistema látero-sensorial cefálico de Characiformes (Ostariophysi): anatomia e seu significado filogenético

“…Informações sobre esse sistema têm sido incluídas em trabalhos de cunho filogenético, porém quase sempre envolvendo caracteres restritos às ossificações e ramificações dos canais sensoriais, utilizando pouca ou nenhuma informação sobre a distribuição dos poros desses canais sensoriais (e.g. Vari, 1983;Vari et al 1995;Zanata & Vari, 2005;Toledo-Piza, 2007 Buckup, 1998;Nelson 2006;Oliveira et al, 2011) além de uma família nova monotípica, possivelmente relacionada à Erythrinoidea (sensu Oyakawa, 1998), atualmente em processo de descrição formal (de Pinna, com. pess).…”

“…Esta morfologia, da maneira como citado acima, é comum aos representantes da família Acestrorhynchidaes da ordem Characiformes, já sugerida como sinapomorfia para os representantes do gênero (Menezes, 1969;Toledo-Piza, 2007). De fato, essa característica é incomum nos táxons incluidos no grupo-externo.…”