Various biometric and geometric measures were used to discriminate between the morphologically similar river puffer, Takifugu obscurus, tiger puffer, T. rubripes, their hybrids, and their triploid hybrids. The hybrids and triploid hybrids had greater anal fin width, nostril width, and snout length than the parental species (p<0.05). However, they had less caudal peduncle depth, inter-orbital width, head length, and head width (p<0.05). The morphometric and meristic characteristics of the hybrids and triploid hybrids were either intermediate between the parental species or more similar to those of one parental species. However, the external morphology of the hybrids and triploid hybrids was predominantly maternal. The triploid hybrids had asymmetry in the fin rays and gill raker numbers. This study identified phenotypic characteristics by distinguishing the morphological variables of river puffer, tiger puffer, their hybrids, and their triploid hybrids.

Abstract
INTRODUCTION
MATERIALS AND METHODS
    1. Fish sampling
    2. Landmark-based morphometrics
    3. Meristic characteristics
    4. Statistical analysis
RESULTS
DISCUSSION
REFERENCES

• In-Seok Park(Division of Convergence on Marine Science, College of Ocean Science and Engineering, Korea Maritime & Ocean University) Corresponding author
• Ji Su Oh(National Agency for Marine Seed Improvement, National Institute of Fisheries Science)