Taxonomic revision of subgenus Awaous (Chonophorus) (Lichtenstein, 1822) and phylogenetic placement within \Stenogobius lineage\ (Gobioidei: Gobiidae)

Author(s)

João Pedro Trevisan dos Santos

• Document type: Master's Dissertation
• Press: Ribeirão Preto.
• Institution: Universidade de São Paulo (USP). Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (PCARP/BC)
• Defense date: 2020-04-15

Examining board members

Flávio Alicino Bockmann; Rodrigo Antunes Caires; Veronica de Barros Slobodian Motta; Alessio Datovo da Silva

• Advisor: Flávio Alicino Bockmann

Abstract

Gobiidae is considered one of the most diverse families of fish, therefore, despite being widely studied, it still has many knowledge gaps. In this family is found Awaous which is diagnosed by the presence of papillae over much of the gill structure. This genus is currently divided into three subgenera, namely Awaous, Chonophorus and Euctenogobius. The subgenus Awaous (Chonophorus) would present three nominal species, Awaous (Chonophorus) banana, Awaous (Chonophorus) lateristriga and Awaous (Chonophorus) tajasica. Unfortunately, the diagnostic characteristics overlap extensively, which made it difficult to understand the real diversity of the subgenera. Thus, a taxonomic revision was implemented. The revision work was based on several characteristics such as ray and scale count, analysis of scale pattern in different regions of the body, analysis of pore patterns of the cephalic sensory canal, cephalic superficial neuromast lines and, for the first time, oral papillae. The results revealed four nominal species, one of them being Awaous (Chonophorus) transandeanus, currently considered a synonym. Moreover, the phylogenetic position of Awaous has always been the subject of intense debate. Initially the genus was considered closely related to the subfamily Sicydiinae, later a member of Gobionellinae and now, with the advent of genetic methodology, Awaous was once again considered close to Sicydiinae. Thus, a phylogenetic analysis based on external morphology, sensory system, osteology and musculature was implemented. Besides proposing new homology for the superficial neuromasts lines, this dissertation is the first attempt to include myological characters. It was demonstrated that Awaous is the sister group of Stenogobius, closely related to Sicydiinae. Thus, the Sicydiinae Subfamily is proposed encompassing Awaous, Stenogobius and the other genera currently allocated in Sicydiinae. The clade formed by Awaous and Stenogobius was named tribe Stenogobini and the clade formed by genera currently allocated in Sicydiinae was called tribe Sicydiini. In addition, the study of phylogenetic relationships among Awaous species revealed that the support for the division of this genus into subgenera is very weak, suggesting that the division of Awaous into three subgenera may not be the most appropriate. (AU)

• FAPESP's process: 17/24989-2 - Taxonomic revision of subgenus Awaous (chonophorus) (Lichtenstein, 1822) and phylogenetic placement within Stenogobius lineage (Gobiiformes: Gobiidae)
• Grantee: João Pedro Trevisan dos Santos
• Support Opportunities: Scholarships in Brazil - Master