The cone snails belong to the superfamily Conoidea, comprising
10,000 venomous marine gastropods. We determined the complete mitochondrial DNA sequence of
Conus textile. The gene order is identical in
Conus textile,
Lophiotoma cerithiformis (another Conoidean gastropod), and the neogastropod
Ilyanassa obsoleta, (not in the superfamily Conoidea). However, the intergenic interval between the
coxI and
coxII genes was much longer in
C. textile (165 bp) than in any other previously analyzed gastropod. We used the intergenic region to evaluate evolutionary patterns. In most neogastropods and three conidean families the intergenic interval is small (<30 nucleotides). Within
Conus, the variation is from 130 to 170 bp, and each different clade within
Conus has a narrower size distribution. In
Conasprella, a subgenus traditionally assigned to
Conus, the intergenic regions vary between 200 and 500 bp, suggesting that the species in
Conasprella are not congeneric with
Conus. The intergenic region was used for phylogenetic analysis of a group of fish-hunting Conus, despite the short length resolution was better than using standard markers. Thus, the
coxI–coxII intergenic region can be used both to define evolutionary relationships between species in a clade, and to understand broad evolutionary patterns across the large superfamily Conoidea.