Rodulf Anthony T. Balisco, Wei-Cheng Jhuang & Te-Yu Liao

Abstract. Sexual dimorphism is a widely observed yet under–documented phenomenon in many fish species, particularly those that are less studied. This study provides the first detailed account of sexual dimorphism in Belobranchus segura based on specimens from the Philippines, Indonesia, and Taiwan. Our findings include new distribution records of B. segura in Palawan and Mindanao Island, and a new distribution record of Belobranchus belobranchus from Palawan in the Philippines. DNA sequencing also revealed the presence of two distinct subclades for both B. segura (Philippines/Taiwan and Indonesia) and B. belobranchus (Philippines/ Indonesia, Indonesia only), each separated by 2.0–2.8% K2P intraspecific genetic distance, suggesting potential species complexes among the samples.

Key words. bully/spiny cheek sleepers, cryptic diversity, freshwater fish diversity, ichthyology

Read article here: RBZ-2025-0043