Identification and phylogenetic analysis of marine sponges in the Jordanian Gulf of Aqaba using DNA barcoding

Sponges (Porifera) are the largest biomass component of coral reefs benthic fauna among marine organisms and are very morphologically diverse. In the present work, we aimed to identify marine sponges in the Jordanian Gulf of Aqaba using the partial 18S rRNA and the 28S rRNA genes as DNA barcoding markers. A total of nine morphologically different marine sponge samples from 6.6m to approximately 22m depth were collected. Sponge fragments were frozen at -80 °C prior to DNA extraction. The sponge's DNA was extracted using a commercial kit and subjected directly to PCR amplification for the 18S rRNA and 28S rRNA genes. The DNA sequences were analyzed using the Basic Local Alignment Search Tool (BLAST) to determine the sponge's identity, and phylogenetic trees were constructed to clarify the relationship among the samples. The results obtained revealed the presence of the following genera: <i>Axinella</i>, <i>Negombata</i>, <i>Siphonochalina</i>, <i>Diacarnus</i>, and an unidentified genus within the order <i>Haplosclerida</i>. Identification of sponge species was difficult due to the scarcity of diagnostic morphological characters. To our knowledge, this is the first study in the Jordanian Gulf of Aqaba that focuses on the morphological and molecular taxonomy of marine sponges using DNA barcoding markers.