The polychromatic and trophically polymorphic Midas cichlid fish species complex (Amphilophus cf. citrinellus) is an excellent model system for studying the mechanisms of speciation and patterns of phenotypic diversification in allopatry and in sympatry. Here, we first review research to date on the species complex and the geological history of its habitat. We analyse body shape variation from ...

Gonadotropin-releasing hormone (GnRH) expressing neurons in the preoptic area (POA) of the hypothalamus plays a key role in regulating reproductive function through the control of gonadotropin release. Several studies have illustrated the importance of the social environment in modulating the size of GnRH expressing neurons. In the African cichlid fish Astatotilapia burtoni, the size of the som...

The cichlid fishes of the East African Great Lakes are the largest extant vertebrate radiation identified to date. These lakes and their surrounding waters support over 2,000 species of cichlid fish, many of which are descended from a single common ancestor within the past 10 Ma. The extraordinary East African cichlid diversity is intricately linked to the highly variable geologic and paleoclim...

The flocks of cichlid fishes in the African Great Lakes are a fascinating system for studies of visual ecology. Separate radiations have produced a diverse flock of several hundred closely related cichlid species in each of the three large lakes (Malawi, Tanganyika and Victoria). Closely related species exhibit a diverse range of color patterns. The three lakes have dramatically different photi...

MicroRNAs (miRNAs) are ancient, short noncoding RNA molecules that regulate the transcriptome through post-transcriptional mechanisms. miRNA riboregulation is involved in a diverse range of biological processes, and misregulation is implicated in disease. It is generally thought that miRNAs function to canalize cellular outputs, for instance as "fail-safe" repressors of gene misexpression. Geno...

Two cichlid populations each found on separate islands in the Bocas del Toro archipelago, Panama were identified as members the genus Astatheros. DNA from each population was isolated and purified and the mitochondrial gene cytochrome b was used as a molecular marker. Resulting sequences were compared with already published cytochrome b sequences of Astatheros from an internet database. Phyloge...

A long history of research focused on the East Africa cichlid radiations (EAR) revealed discrepancies between mtDNA and nuclear phylogenies, suggesting that interspecific hybridisation may have been significant during the radiation of these fishes. The approximately 250 cichlid species of Lake Tanganyika have their roots in a monophyletic African cichlid assemblage, but controversies remain abo...

A new species of hornshark is described from northwestern Australia based on six whole specimens and a single egg case. Heterodontus marshallae n. sp. was previously considered to be conspecific with H. zebra the Western Pacific. The differs in sequence its NADH2 gene, several morphological characters, case morphology key coloration features. Despite being similar between zebra, i.e., pale back...