Meeting Abstract
The toadfishes (Batrachoidiformes) are a monophyletic group of bottom-dwelling fishes. One specialization of the skeleton of this group is an enlarged anterior precaudal vertebrae, with the third and fourth neural spines articulating tightly with modified pterygiophores. These derived pterygiophores support the dorsal spines and are historically called as “Basalia”. The first epineural, which is enlarged and heavily ossified, also interacts with the bones of this region, articulating with the neural arch of the first vertebra. Although this overall arrangement has been proposed as a synapomorphy of Batrachoidiformes, but this seems a bold statement given the poor taxon sampling for this character. Furthermore, the interrelationships among the species of Batrachoidiformes and the relationship of this order to other percomorph fishes are not entirely resolved. To assess morphological variations in this skeletal complex, 42 species representing the four sub-families of Batrachoidiformes were examined using CT-scans and cleared and stained specimens. The aim was to identify characters that may be phylogenetic informative. We found that each sub-family has a distinct epineural arrangement and unique pterygiophore morphology. For example, in Halophryinae and Batrachoidinae, the pterygiophores that support the second and third spines articulate with the neural spine of the fourth vertebra. This condition of two pterygiophores articulating with a single neural spine is unique among Batrachoidiformes and most of other percomorph fishes. This condition, therefore, can be interpreted as synapomorphy grouping these two subfamilies.
