Identification of gelodok fish (Perciformes, Gobiidae) in a coastal mangrove ecosystem, based on morphological and molecular characteristics

Abstract

Gelodok fish (mudskippers) are a subfamily of amphibian fish commonly found living in mangrove ecosystems, one of which is in Tabongo Village, Dulupi District, Boalemo Regency, Gorontalo Province. It is difficult to distinguish between species of this fish because they have very similar characteristics. This study aims to (1) determine the detailed morphological characteristics that distinguish gelodok fish species; and (2) determine the molecular characteristics of gelodok fish species found in coastal mangrove ecosystem of Tomini Bay, Tabongo Village, Boalemo Regency, Gorontalo. This research was conducted from 2022 to 2023 using purposive sampling method. Morphological characteristics were performed for 39 characters. Geometric-morphometric analysis was performed using ImageJ software with 10 land marks. Amplification of COI sequences was carried out with F1R1 and F2R2 primers. Based on morphological characteristics, it is known that two species of gelodok fish are found in the area, namely Periophthalmus argentilineatus and P. malaccensis. COI sequencing results of the samples confirmed one species of gelodok fish found in the area, namely P. argentilineatus. The other species cannot be definitively identified as P. malaccensis due to the absence of COI sequences for that species in GeneBank.