Reassessment of Morphological Diagnostic Characters and Species Boundaries Requires Taxonomical Changes for the Genus Orthopyxis L. Agassiz, 1862 (Campanulariidae, Hydrozoa) and Some Related Campanulariids

Author(s)

Cunha, Amanda F. ^[1] ; Genzano, Gabriel N. ^[2] ; Marques, Antonio C. ^{[3, 1]}

Affiliation

^[1] Univ Sao Paulo, Inst Biociencias, Dept Zool, Sao Paulo - Brazil

^[2] Univ Nacl Mar del Plata, CONICET, IIMyC, Estn Costera Nagera, Dept Cs Marinas, Mar Del Plata, Buenos Aires - Argentina

^[3] Univ Sao Paulo, Ctr Biol Marinha, Sao Paulo - Brazil

• Document type: Journal article
• Source: PLoS One; v. 10, n. 2 FEB 27 2015.
• Web of Science Citations: 18

Abstract

The genus Orthopyxis is widely known for its morphological variability, making species identification particularly difficult. A number of nominal species have been recorded in the southwestern Atlantic, although most of these records are doubtful. The goal of this study was to infer species boundaries in the genus Orthopyxis from the southwestern Atlantic using an integrative approach. Intergeneric limits were also tested using comparisons with specimens of the genus Campanularia. We performed DNA analyses using the mitochondrial genes 16S and COI and the nuclear ITS1 and ITS2 regions. Orthopyxis was monophyletic in maximum likelihood analyses using the combined dataset and in analyses with 16S alone. Four lineages of Orthopyxis were retrieved for all analyses, corresponding morphologically to the species Orthopyxis sargassicola (previously known in the area), Orthopyxis crenata (first recorded for the southwestern Atlantic), Orthopyxis caliculata (= Orthopyxis minuta Vannucci, 1949 and considered a synonym of O. integra by some authors), and Orthopyxis mianzani sp. nov. A re- evaluation of the traditional morphological diagnostic characters, guided by our molecular analyses, revealed that O. integra does not occur in the study area, and O. caliculata is the correct identification of one of the lineages occurring in this region, corroborating the validity of that species. Orthopyxis mianzani sp. nov. resembles O. caliculata with respect to gonothecae morphology and a smooth hydrothecae rim, although it shows significant differences for other characters, such as perisarc thickness, which has traditionally been thought to have wide intraspecific variation. The species O. sargassicola is morphologically similar to O. crenata, although they differ in gonothecae morphology, and these species can only be reliably identified when this structure is present. (AU)

• FAPESP's process: 11/22260-9 - Morphological variation and its phylogenetic signal in marine colonial organisms: a study with the family Campanulariidae (Cnidaria, Hydrozoa)
• Grantee: Amanda Ferreira e Cunha
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 13/50484-4 - Biodiversity and distribution patterns of the Medusozoa form the South-Western Atlantic
• Grantee: Antonio Carlos Marques
• Support Opportunities: Regular Research Grants
• FAPESP's process: 11/50242-5 - Dimensions of marine life: patterns and process of diversifications in planktonic and benthic cnidarians
• Grantee: Antonio Carlos Marques
• Support Opportunities: BIOTA-FAPESP Program - Thematic Grants
• FAPESP's process: 04/09961-4 - Biodiversity, evolution, endemism and conservation of the Medusozoa from the Southwestern Atlantic
• Grantee: Antonio Carlos Marques
• Support Opportunities: Research Projects - Thematic Grants