Cryptic Caribbean species of Scorpaena (Actinopterygii: Scorpaeniformes) suggested by cytogenetic and molecular data

Abstract

Cytogenetic and molecular analyses enabled identification of two cytotypes among individuals of the spotted scorpion fish Scorpaena plumieri from Margarita Island, Venezuela. Cytotype 1 was characterized by 48 subtelo-acrocentric chromosomes and fundamental number (number of chromosome arms; FN) equalled 48, while cytotype 2 was characterized by two metacentric and 46 subtelo-acrocentric chromosomes and FN was 50. These cytotypes also differed in the location of the ribosomal gene clusters and in the distribution of the constitutive heterochromatin. Moreover, fish from the cytotypes 1 and 2 were found to belong to distinct mitochondrial lineages. The presence of two S. plumieri cytotypes from two lineages separated by high genetic distance suggests that they correspond to sympatric cryptic species.

The Amazon‐Orinoco Barrier as a driver of reef‐fish speciation in the Western Atlantic through time

“…This indicates a separation between the Caribbean and South Atlantic lineages promoted by the Amazon‐Orinoco Barrier and subsequent isolation of populations off Brazil and the Eastern Atlantic (Araujo et al, 2020; Beldade et al, 2009; Floeter et al, 2008). In the case of Scorpaena , it is likely that the Amazon‐Orinoco Barrier was responsible for an older cladogenetic event that was subsequently followed by a more recent division between lineages, originating the species that now lives in the tropical Eastern Pacific and the Caribbean (Figure S74; Nirchio et al, 2016). This secondary cladogenetic event was likely promoted by the emergence of the Isthmus of Panama at 3–5 Mya (Bacon et al, 2015; Coates & Stallard, 2013; Leigh et al, 2013; Montes et al, 2012).…”

Lesser devil rays Mobula cf. hypostoma from Venezuela are almost twice their previously reported maximum size and may be a new sub‐species

“…Similarly, Nirchio et al . () reported the presence of two sympatric and cryptic species of fishes for Margarita Island (Venezuela) based on cytogenetic and molecular studies. Similar tools might be used to resolve the questions raised by the three specimens reported here regarding the Mobula species in the western Atlantic Ocean.…”

Molecular Analysis and Chromosome Mapping of Repetitive DNAs in the Green TerrorAndinoacara rivulatus(Cichlidae: Cichlasomatini)

“…15 Fish cytogenetics is a very active research area that provides information for taxonomy and for the understanding of the phylogenetic relationships among taxa. [16][17][18][19][20][21][22][23] The most recent checklist of cytogenetically analyzed fish species reveals that only *8% of cichlid fishes are included. 24 The diploid number in the group ranges from 2n = 32 to 2n = 60, but in neotropical cichlids, the modal diploid number is 2n = 48.…”