TY - JOUR AU - Silva-Morales, Itzahí AU - López-Aquino, Mónica J. AU - Islas-Villanueva, Valentina AU - Ruiz-Escobar, Fernando AU - Bastida-Zavala, J. Rolando PY - 2019/07/01 Y2 - 2024/03/29 TI - Morphological and molecular differences between the Amphiamerican populations of Antillesoma (Sipuncula: Antillesomatidae), with the description of a new species JF - Revista de Biología Tropical JA - Rev. Biol. Trop. VL - 67 IS - S5 SE - Articles DO - 10.15517/rbt.v67iS5.38934 UR - https://revistas.ucr.ac.cr/index.php/rbt/article/view/38934 SP - S101–S109 AB - <p class="p1"><strong>Introduction: </strong>The sipunculans are a group of marine invertebrates that have been little studied in the tropical eastern Pacific (TEP). <em>Antillesoma antillarum</em> is a species belonging to the monospecific family Antillesomatidae, considered widely distributed in tropical and subtropical localities across the globe. <strong>Objective:</strong> The main objective of this work was to examine the morphological and molecular differences between specimens from both coasts of tropical America to clarify the taxonomy of this species. <strong>Methods:</strong> We examined the morphology with material from the Mexican Caribbean and southern Mexican Pacific. To perform molecular analyses, two sequences of the COI molecular marker were obtained from specimens collected in Panteón Beach, Oaxaca, southern Mexican Pacific, and compared with four sequences identified as <em>A. antillarum </em>in GenBank, all of them from different localities. A phylogenetic reconstruction was performed with the maximum likelihood method and genetic distances were calculated with the Kimura 2P model and compared to reference values. <strong>Results:</strong> The phylogenetic analysis revealed three different lineages of <em>Antillesoma </em>that are well supported by bootstrap values: <em>Antillesoma antillarum sensu stricto</em> from the Caribbean Sea and Florida; a sister group to the one represented by our samples from the Mexican Pacific; and a third group from Thailand. <strong>Conclusion: </strong>Based on morphological traits and molecular data, <em>Antillesoma mexicanum </em><strong>sp. nov.</strong> is described from the Mexican Pacific, differing from <em>A. antillarum </em>in the trunk papillae, color patterns and, additionally, the specimens from the Caribbean attain significantly bigger trunk sizes than the ones Pacific.</p> ER -