On a remarkable sexual dimorphic trait in the Characiformes related to the olfactory organ and description of a new miniature species of Tyttobrycon Gery (Characiformes: Characidae)

Author(s)

Abrahao, Vitor Pimenta ^{[1, 2]} ; Pastana, Murilo ^[1] ; Marinho, Manoela ^{[1, 3]}

Affiliation

^[1] Univ Sao Paulo, Museu Zool, Sao Paulo, SP - Brazil

^[2] Univ Fed Bahia, Inst Biol, Programa Posgrad Biodiversidade & Evolucao, Rua Barao Geremoabo, Salvador, BA - Brazil

^[3] Univ Fed Paraiba, Dept Sistemat & Ecol CCEN, Lab Sistemat & Morfol Peixes, Campus 1, Joao Pessoa, PB - Brazil

• Document type: Journal article
• Source: PLoS One; v. 14, n. 12 DEC 18 2019.
• Web of Science Citations: 1

Abstract

Among the order Characiformes, secondary sexual dimorphism is commonly associated to the occurrence of bony hooks on fins, shape and length of the dorsal and anal fins, and sexual dichromatism. The analysis of a new miniature Characidae species of the genus Tyttobrycon, described herein, yielded to the discovery of a sexually dimorphic trait related to nostril aperture and number of olfactory lamellae. In this type of dimorphism, mature males present larger nostril aperture and higher number of olfactory lamella than females. A dimorphic olfactory organ is for the first time recorded and described for a member of the Characiformes. Gross morphology and development of brain and peripheral olfactory organ of Tyttobrycon sp. n. are described and compared to other species of Characidae. It is hypothesized that such dimorphic trait is related to male-male detection during cohort competition in small characids. The new species of Tyttobrycon is diagnosed from its congeners by the number of branched anal-fin rays (19-21) and the absence of a caudal-peduncle blotch. It occurs in a small tributary of Rio Madeira basin, near to the limit between Brazil and Bolivia, Acre State, Brazil. (AU)

• FAPESP's process: 17/09321-5 - Miniature Characiformes (Teleostei: Ostariophysi): evolution, diversity and biogeography
• Grantee: Manoela Maria Marinho Koh
• Support type: BIOTA-FAPESP Program - Young Investigators Grants
• FAPESP's process: 17/17957-7 - COMPARATIVE NEUROANATOMY IN CETOPSIDAE (OSTARIOPHYSI: SILURIFORMES) AND SIMULTANEOUS ANALYSIS OF MORPHOLOGICAL AND MOLECULAR DATA
• Grantee: Vitor Pimenta Abrahão
• Support type: Scholarships abroad - Research Internship - Doctorate
• FAPESP's process: 14/11397-1 - Phylogenetic relationships in the family Cetopsidae (Osteichthyes, Ostariophysi, Siluriformes) with simultaneous analysis of morphological and molecular data
• Grantee: Vitor Pimenta Abrahão
• Support type: Scholarships in Brazil - Doctorate
• FAPESP's process: 12/22685-2 - Canals and pores of the cephalic laterosensory system of Characiformes (Ostariophysi): anatomy and phylogenetic information.
• Grantee: Murilo Nogueira de Lima Pastana
• Support type: Scholarships in Brazil - Master
• FAPESP's process: 15/26804-4 - Integrating morphological and molecular data in the systematics of three siluriform subgroups: subfamily Copionodontinae (Trichomycteridae), genus Pimelodella (Heptapteridae) and family Cetopsidae
• Grantee: Mario Cesar Cardoso de Pinna
• Support type: Regular Research Grants
• FAPESP's process: 16/19075-9 - Diversity and evolution of Gymnotiformes (Teleostei, Ostariophysi)
• Grantee: Naercio Aquino Menezes
• Support type: Research Projects - Thematic Grants