Meeting Abstract

P3-39   -   Don’t Wanna Be Your Bony Wrench: Skeletal Morphology of the Opercular Series of Dwarfgobies. Vaz, D B*; Tornabene, L; Goatley, C; Museum of Comparative Zoology, Harvard University; Burke Museum of Natural History and Culture University, of Washington; University of New England, Australia dbistonvaz@fas.harvard.edu https://mcz.harvard.edu/people/diego-f-b-vaz

The genus Eviota is a speciose group of cryptobenthic fishes distributed across Indo-Pacific coral reefs. Commonly known as dwarfgobies because of their diminutive size (< 30 mm), species of this genus are characterized by for having a very short life span of less than 100 days. Integrative taxonomy in conjunction with underwater photography employed in the last thirty years has led to an explosion in descriptions of new species. The genus currently contains 128 species. Despite the recent advances on the taxonomy of Eviota, several aspects of the biology of this group are still unknown, such as skeletal anatomy and feeding mechanics. This study firstly presents detailed accounts of the skull of more than 30 species of Eviota, with particular focus on the opercular series and the hyoid arch. The interopercle of all examined species of Eviota extends anteriorly and contacts the lower jaw, completely lacking the retroarticular-interopercle ligament, whereas in other gobies the interopercle does not contact and is connected to the lower jaw through the retroarticular-interopercle ligament. In the species of Eviota belonging to a monophyletic group united by the presence of unbranched pectoral-fin rays, the posterior tip of the interopercle is rounded and does not contact the posterior ceratohyal, similar to other gobies. Conversely, species in a clade of Eviota united by branched pectoral-fin rays have the posterior tip of the interopercle shaped like a wrench, which articulates directly with a process in the posterior ceratohyal. This condition is different than the observed in any other Gobiidae to date. The phylogenetic significance and potential modifications to feeding mechanics resulting from this unique interopercular arrangement is discussed.