BackgroundThree specimens of Puerulus mesodontus Chan, Ma & Chu, 2013 (Crustacea, Decapoda, Achelata, Palinuridae) were collected from Palabuhanratu Bay, southern Java, Indonesia. There is no previous record on the presence of the species in Indonesia. This finding represents the first record of this species in Java, Indonesia, and confirms that the species is present in the Indian Ocean. The morphological characters of the species are described.New informationThis paper contains a new distribution record of a lobster species from Indonesian waters.

Abstrak : Variasi bentuk dan pola pewarnaan tubuh ikan kerapu (Famili Serranidae) sangat variatif, sehingga pengenalan spesies secara morfologis sering tidak akurat. Penelitian ini bertujuan untuk mengautentikasi ikan kerapu dengan menggunakan marka gen COI. Contoh ikan kerapu yang diamati berjumlah 29 ekor yang dikumpulkan dari tiga tempat pendaratan ikan di Perairan Peukan Bada, Propinsi Aceh. Secara karakter morfologis, ikan kerapu tersebut teridentifikasi lebih dari 8 spesies. Untuk analisis DNA, sebanyak 30 mg daging sirip dari setiap ikan contoh diambil untuk dilakukan isolasi dan ekstraksi DNA, kemudian visualisasi elektroforesis dan fragmentasi DNA gen COI dengan metode PCR-sekuensing. Setelah diekstraksi, diperoleh 20 sampel DNA yang tervisualisasi dengan baik, yang dari jumlah tersebut terdapat 16 sampel dapat diamplifikasi. Hasilnya menunjukkan terdapat 6 spesies yang terautentikasi. Kelompok pertama adalah Variola albimarginata, Cephalopholis urodeta, dan C. sexmaculata dengan tingkat kemiripan ≥ 97%. Berikutnya C. boenak, Epinephelus merra, dan Scolopsis vosmeri tingkat kemiripannya ≤ 97%. Bila dibandingkan hasil autentikasi DNA, hasil penelitian menunjukkan bahwa 13 sampel atau > 80% tidak teridentifikasi dengan benar secara morfologis. Berdasarkan jarak genetik, pohon filogeni membentuk 2 clade antara Serranidae dan Nemipteridae. Hasil penelitian menunjukkan bahwa penggunaan marka gen COI sangat efektif untuk autentikasi spesies yang dapat dijadikan sebagai instrumen dalam pemanfaatan dan pengelolaan ikan kerapu.Kata kunci : kerapu, variasi morfologi, gen MT-COI, autentikasi.Abstract : The groupers (family Serranidae) show high variability both in body shapes and coloration leads to highly morphological-based misidentification. The research was aimed in autenthication of the grouper species using MT-COI gene. A total of 29 grouper fishes were collected from three fish landing sites of Peukan Bada, Aceh Province. These fishes were morphologically identified from which more than 8 species were obtained. A 30 mg of the fin meat of each sample was taken for DNA extraction, isolation, electrophoresis visualization, and DNA fragmentation of COI gene using PCR-sequenching.  There were 20 DNA samples was clearly visualized of which 16 has been proceeded for amplification. The results showed that V. albimarginata, C. urodeta, and C. sexmaculata showed ≥ 97% similarity, whereas C. boenak, E. merra, dan S. vosmeri with ≤ 97% similarity. Based on phylogenetic tree analysis there was 2 clearly different clades separating family of Serranidae and Nemipteridae. The use of MT-COI gene was effective and accurate tool in species authentication which could be used as an instrument for utilization and management of the grouper species.Keywords : groupers, morphological variation, MT-COI gene, autenthication.

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Measurements of the dimensions of the different gills and the suprabranchial chambers have been made and the data analysed with respect to body weight using logarithmic transformations (Y = aWb). The slope (b) for area of the total gill surface is 0–592 and for the supra‐branchial chamber 0–696, and their combined respiratory surface: 0–623. The slope values for the surface areas of the 1st, 2nd, 3rd and the 4th gill arches were 0–595,0–578,0–614 and 0–572 respectively. The slope for secondary lamellae/mm is –0138 and that for the bilateral surface area of an average‐sized lamella 0–304. These results indicate differences in growth patterns for the dimensions of the different gills. The growth‐related decrease in the number of secondary lamellae/mm and size of an average secondary lamella together with evidence from “drowning” experiments and diffusing capacity calculation, suggest that this fish is better adapted for aquatic respiration than Anabas or Saccobranchus. The slopes for the total respiratory surface area and gill area seem to be comparatively low in this species.

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