Kladistik Genera Famili Leiognathidae melalui Penelusuran Morfologi Eksternal dan Otolith

Abstract

Anggota famili Leiognathidae atau Peperek termasuk dalam kategori minor commercial, berfungsi sebagai komoditas ketahanan pangan sehingga kurang mendapat perhatian untuk diteliti. Penelitian ini bertujuan untuk membuktikan hipotesis penemuan seluruh genera dari Leiognathidae pada perairan Pantai Jawa Timur. Sampel ikan dikoleksi dari hasil tangkapan nelayan dengan alat penangkapan ikan; Jaring Tarik, Cantrang, dan Mini-Trawl dari Januari 2023 sampai Oktober 2024. Analisis genus dilakukan melalui deskripsi morfologi eksternal, morfometri, dan penyelidikan otolith. Studi otolith dilakukan melalui koleksi sagittae dari tulang telinga di belakang otak. Analisis morfometri untuk memperjelas definisi bentuk tubuh menggunakan perangkat lunak TpsDig. Total 12 variabel morfologi digunakan untuk menjelaskan masing-masing kerabat pada genus. Sementara deskripsi otolith dianalisis dengan menggunakan 15 variabel bentuk, cekungan, dan tonjolan dari otolith. Dendogram dihasilkan dari analisis morfologi dan otolith untuk memisahkan kekerabatan di antara genus. Hasil analisis membuktikan bahwa terdeskripsi total 10 genera dari famili Leiognathidae yaitu; Leiognathus, Aurigequula, Eubleekeria, Photopectoralis, Nuchequula, Karalla, Gazza, Deveximentum, Equulites, dan Photolateralis. Genus Gazza ditemukan pada seluruh lokasi sampling. Namun genus Karalla hanya ditemukan pada lokasi sampling di Selatan Barat Jawa Timur (Pantai Dangkal Pacitan, dan Prigi Trenggalek). Hasil analisis dendogram berhasil menempatkan Equulites satu kerabat dengan Photolateralis, namun tidak berhasil memisahkan antara Leiognathinae dengan Gazzinae. Sebaliknya, analisis menggunakan morfologi otolith tidak berhasil menempatkan Equulites satu kelompok dengan Photolateralis, namun bisa memisahkan antara sub famili Leiognathinae dengan Gazzinae. Kondisi lingkungan geografis mungkin menjadi faktor utama terjadinya adaptasi morfologi eksternal dan otolith yang berbeda. Deskripsi morfologi dan otolith bisa digunakan sebagai indikator apomorfi genus. Analisis genetik melalui DNA barcoding masih diperlukan untuk menelusuri kekerabatan diantara genus. Members of family Leiognathidae are included in the minor commercial category, functioning as a food security commodity so that they have received less attention for research. The study aims to prove the hypothesis of the discovery of all genera of Leiognathidae within coastal waters of East Java. Fish samples were collected from the catches of fishermen using fishing gear; Beach Seine, modified Danish Seine, and Mini-Trawl, from January 2023 to October 2024. Genera analysis was carried out through external morphological descriptions, morphometry, and otolith investigations. Otoliths were collection of sagittae from the ear bones behind the brain. Morphometric analysis to clarify the definition of body shape were using TpsDig software. A total of 12 morphological variables were used to describe each genus within family. While the otolith description was analyzed using 15 variables of shape, depression, and protrusion of the otolith. Each dendrogram was generated from morphological and otolith analysis to separate the clade among genera. The results of the analysis proved that all 10 genera of Leiognathidae were described, consisting of: Leiognathus, Aurigequula, Eubleekeria, Photopectoralis, Nuchequula, Karalla, Gazza, Deveximentum, Equulites, and Photolateralis. The genus Gazza was found in all sampling locations. However, the genus Karalla was only described in two sampling locations in Southwest of East Java (Pantai Dangkal Pacitan, and Prigi Trenggalek). The results of dendogram analysis succeeded in placing Equulites in the same clade as Photolateralis, but failed to separate Leiognathinae from Gazzinae. On the other hand, the analysis using otolith morphology failed to place Equulites in the same group as Photolateralis, but could separate Leiognathinae from Gazzinae. Geographical barriers and environmental factors might be the main factor in the occurrence of different morphological and otolith adaptations. Genera can be distinguished through external morphology and otolith description. Genetic analysis through DNA barcoding is still needed to trace the lineage among genera of Leiognathidae.

Keywords

• peperek
• morfologi eksternal
• otolith
• deskripsi genus
• ponyfish
• slipmouth
• morphology