Sparks Lab Research Projects

Research activities in my lab are currently
focused on investigating the morphological and functional evolution of specialized hearing in cichlids (supported by NSF) via comparative studies of the otophysic (gas bladder-inner ear) connection in this clade, as well as neuroanatomical studies directed toward reconstructing mid- and hindbrain evolution in cichlids using 3D imaging (MRI) and traditional histological techniques. Via collaborative physiological studies with colleague Chris Braun
(CUNY/Hunter College), we are directly measuring the auditory abilities of cichlids using ABR methodology. 

Multi-disciplinary studies examining the evolution and function of bioluminescent signaling systems in both shallow water and deep-sea marine fishes are continuing (supported by two current NSF awards), with a focus on the bacterially driven luminescent system in ponyfishes (Leiognathidae) and other sexually-dimorphic luminescent clades.
To facilitate these studies, we are collaborating with colleagues at UCSD and Scripps Institution of Oceanography (DFL) to develop, refine, and implement 3D MRI technology for visualizing and analyzing soft tissue structures in bioluminescent marine fishes (light organs and photophores) and cichlids (otophysic [gas bladder-inner ear] connection). Related to these two studies , we are investigating trends in the evolution of the brain and nervous system in relation to audition, acoustics, sensory abilities, and communication in both freshwater and marine fishes. Our studies on bioluminescence have benefited from numerous surveys of coastal and deep-water (mesopelagic) Indo-Pacific marine fishes by our group, focusing on clades that exhibit bioluminescence, and that have led us to question a number of long held, but rarely tested hypotheses regarding widespread marine taxa and dispersal capability in marine fishes.

Through fieldwork in remote southwestern and northern Madagascar, my lab is
also investigating the diversity, biogeography, and systematics of the endemic Malagasy cavefishes.
These obligate, blind and pigment-free, cave-dwelling gobioid fishes are endemic to karst habitats in arid portions of southwestern and far northern Madagascar. Through higher-level morphological and molecular phylogenetic studies of both freshwater and marine fish clades, I am also   interested in Gondwanan biogeography and paleogeography, with an emphasis on the western Indian Ocean and the origin(s) of Madagascar's freshwater and nearshore marine fish clades.

Exploratory fieldwork, ichthyofaunal inventories, and collection building continue
to be essential components of my research activities. To date, a total of 18 foreign collecting expeditions (12 completed at AMNH) have been conducted in collaboration with colleagues in Madagascar, Curaçao, Ecuador, Venezuela, Taiwan, Singapore, Malaysia, Thailand, Sri Lanka, Indonesia, Qatar, Oman, and Vietnam, and additional trips are planned for 2011, including Madagascar and Eastern Africa.
In addition, numerous expeditions have been undertaken in the US, including studies of endangered percids in the Great Lakes region, desert fishes of the southwestern US, and deep-sea collecting off of the California coast. Collections obtained on these expeditions include numerous taxa new to the AMNH, numerous species new to science, and have significantly augmented and diversified our collections of Malagasy, Indian Ocean, Western Pacific, mesopelagic, and deep-sea fishes.