Tracing the Evolution of Venom in Scorpionfishes and Waspfishes

2011 REU Intern Elizaveth Everman


Junior Biology major at William Jewell College

REU Mentor: Dr. Leo Smith (Curator, Zoology, Fishes)

Symposium Presentation Title: The phylogeny of scorpionfishes and stonefishes (Teleostei:  Scorpaenoidei) and its implications for the evolution of venom

Symposium Presentation Abstract: Morphological and molecular datasets are combined to analyze the inter-relationships and intra-relationships of the Scorpaenoidei fishes.   This phylogenetic analysis is also used to infer the evolution of characters such as the evolution of venom, live birth and modified pectoral rays.  Data were collected for 50 taxa representative of three outgroups and 18 scorpaenoid families, including the venomous Scorpaenidae, Sebastidae, Setarchidae, Synanceiidae, Apistidae, Tetrarogidae, Aploactinidae, Gnathanacanthidae, Neosebastidae, and their relatives Pataecidae, Bembridae, Parabembridae, Plectrogeniidae, Congiopodidae, Triglidae, Peristediidae, Hoplichthyidae and Platycephalidae.  The scorpaeoid relationships are distinct from previous hypotheses based on either morphological or molecular data.  Ancestral states reconstruction shows that the evolution of characters such as venom and pectoral rays occurred multiple times. It is probable that an increased number of taxa will provide greater insight and further resolve the interrelationships and intra-relationships of the scorpaenoid fishes.

Original Project Description: Scorpionfishes and waspfishes include the most venomous fishes in the world.  For nearly 200 years, biologists have assumed that these fishes had a common venomous ancestor, but recent work has caused us to question this assumption by demonstrating that the waspfishes and scorpionfishes are not each other's closest ally.  The goals of this project are to generate a comprehensive phylogeny for all of the major fish groups nested within this toxic suborder of fishes to work out the detailed evolutionary scenario for venom evolution and loss.  The REU participant in this project will complete the DNA sequencing component of this phylogenetic and macroevolutionary question to complement the existing morphological component.  If interested, the REU participant can also explore the anatomical implications of the resulting phylogeny.  This study will not only resolve questions about the evolutionary biology of fishes and venoms, but it will also have implications for public health.

Research methods and techniques: The REU participant in the project will receive an introduction to scorpionfish morphology, fish venom evolution, and systematics.  The participant will get hands-on training in all aspects of DNA extraction through sequencing.  Further, the participant will get detailed training in phylogenetic analysis as well as the comparative methods necessary to trace the evolution of venom and the effect that this adaptation has had on scorpionfish diversification.