My research aims to study the evolution of fish in analyzing large molecular datasets with phylogenetic, age estimation, character reconstruction and ancestral range reconstruction methods.
I currently work on the following projects:
I currently work on the following projects:
- Systematics and biogeography of Indo-West Pacific sardines and anchovies (Clupeoidei: Clupeiformes) [USM-funded].
- Molecular evolution of the African weakly electric fishes (Mormyroidea) and the origin of their electric sense.
- Evolutionary history of bony-tongue fishes (Osteoglossomorpha), focusing on the African freshwater butterfly fish (Pantodon buchholzi) and the African and Asian knifefishes (family Notopteridae).
Systematics and biogeography of Clupeoidei (Clupeiformes)
[Collaborators: Prachya Musikasinthorn (Kasetsart University)]
The clupeoid fishes are worldwide distributed, with marine, freshwater and euryhaline species living in either tropical or temperate environments. Regional endemism is important at the species and genus levels, and the highest species diversity is found in the tropical marine Indo-West Pacific region.
In this large project, we examine the early biogeography of the Clupeoidei in reconstructing the evolution of their environmental preferences (i.e. temperature and salinity preferences) and their ancestral range distributions on a time-calibrated mitogenomic phylogeny.
Our preliminary results support 1) the distinction of several well supported phylogenetic lineages within the Clupeoidei, some of them new; 2) several independent transitions from a marine to freshwater environment and from a tropical to temperate environment that occurred after the initial diversification period of the Clupeoidei; and 3) the tropical marine precursor to the present Indo-West Pacific region during the Cretaceous period was the possible region of origin and diversification of the Clupeoidei.
The clupeoid fishes are worldwide distributed, with marine, freshwater and euryhaline species living in either tropical or temperate environments. Regional endemism is important at the species and genus levels, and the highest species diversity is found in the tropical marine Indo-West Pacific region.
In this large project, we examine the early biogeography of the Clupeoidei in reconstructing the evolution of their environmental preferences (i.e. temperature and salinity preferences) and their ancestral range distributions on a time-calibrated mitogenomic phylogeny.
Our preliminary results support 1) the distinction of several well supported phylogenetic lineages within the Clupeoidei, some of them new; 2) several independent transitions from a marine to freshwater environment and from a tropical to temperate environment that occurred after the initial diversification period of the Clupeoidei; and 3) the tropical marine precursor to the present Indo-West Pacific region during the Cretaceous period was the possible region of origin and diversification of the Clupeoidei.
Evolution of the African weakly electric fishes (Mormyroidea)
[Collaborators: John Sullivan (CUMV) and Carl Hopkins (Cornell University)]
The African families Mormyridae (18 genera, about 200 species) and Gymnarchidae (one species: Gymnarchus niloticus) form the largest group of freshwater electric fishes, the superfamily Mormyroidea. Gymnarchus niloticus occurs in the Nilo-Sudanian ichthyofaunal province whereas mormyrids are distributed throughout all African freshwaters, excepting those in the northernmost Mahgreb and southernmost Cape provinces. Highest mormyrid diversity along with elevated levels of endemism occur in river and stream habitats within forested regions of the Congo, Lower Guinean and Upper Guinean ichthyofaunal provinces.
Mormyrids and Gymnarchus niloticus are largely nocturnal and possess complex electrosensory and electromotor systems used for electrolocation and communication. Numerous studies have been conducted to identify and describe the specialized organic structures engaged in this sense and better understand their function.
My long-standing work on these fishes aims to formulate a comprehensive hypothesis for the origin and evolution of the electric signal-based communication system using time-calibrated phylogenetic inference.
The African families Mormyridae (18 genera, about 200 species) and Gymnarchidae (one species: Gymnarchus niloticus) form the largest group of freshwater electric fishes, the superfamily Mormyroidea. Gymnarchus niloticus occurs in the Nilo-Sudanian ichthyofaunal province whereas mormyrids are distributed throughout all African freshwaters, excepting those in the northernmost Mahgreb and southernmost Cape provinces. Highest mormyrid diversity along with elevated levels of endemism occur in river and stream habitats within forested regions of the Congo, Lower Guinean and Upper Guinean ichthyofaunal provinces.
Mormyrids and Gymnarchus niloticus are largely nocturnal and possess complex electrosensory and electromotor systems used for electrolocation and communication. Numerous studies have been conducted to identify and describe the specialized organic structures engaged in this sense and better understand their function.
My long-standing work on these fishes aims to formulate a comprehensive hypothesis for the origin and evolution of the electric signal-based communication system using time-calibrated phylogenetic inference.
Morphological stasis in the African freshwater butterfly fish (Pantodon)
[Collaborators: Masaki Miya ( Natural History Museum & Institute, Chiba), Matthew Arnegard (Fred Hutchinson Cancer Research Center), Peter McIntyre (The University of Wisconsin), Victor Mamonekene (Université Marien Ngouabi) and Mutsumi Nishida (The University of Tokyo)]
The relationship between genotypic and phenotypic divergence over evolutionary time varies widely, and cases of rapid phenotypic differentiation despite genetic similarity have attracted much attention. Recently, my co-authors and me discovered an extreme case of the reverse pattern—morphological stasis despite massive genetic divergence—in the African freshwater butterfly fish (Pantodon buchholzi).
We estimated the divergence time between the two allopatric populations of Pantodon to be >50 million years. Within osteoglossomorphs, Pantodon exhibits the slowest rate of morphological divergence despite a level of genetic differentiation comparable to both species-rich (e.g., Mormyridae) and species-poor (e.g., Osteoglossidae) families. Morphological stasis in these two allopatric lineages of Pantodon offers a living vertebrate model for investigating phenotypic stability over millions of generations in the face of profound fluctuations in environmental conditions.
At present, I attempt to describe in more details the inter- and intra-population structure of Pantodon using molecules and morphology.
The relationship between genotypic and phenotypic divergence over evolutionary time varies widely, and cases of rapid phenotypic differentiation despite genetic similarity have attracted much attention. Recently, my co-authors and me discovered an extreme case of the reverse pattern—morphological stasis despite massive genetic divergence—in the African freshwater butterfly fish (Pantodon buchholzi).
We estimated the divergence time between the two allopatric populations of Pantodon to be >50 million years. Within osteoglossomorphs, Pantodon exhibits the slowest rate of morphological divergence despite a level of genetic differentiation comparable to both species-rich (e.g., Mormyridae) and species-poor (e.g., Osteoglossidae) families. Morphological stasis in these two allopatric lineages of Pantodon offers a living vertebrate model for investigating phenotypic stability over millions of generations in the face of profound fluctuations in environmental conditions.
At present, I attempt to describe in more details the inter- and intra-population structure of Pantodon using molecules and morphology.
Page last updated: 2 May 2020
