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Inside the National Museum of Natural History, Smithsonian Institution collections: unraveling the genus Narcissia gray, 1840 (Echinodermata: Asteroidea: Ophidiasteridae) from morphological studies

Grant number: 18/06311-1
Support type:Scholarships abroad - Research Internship - Master's degree
Effective date (Start): August 01, 2018
Effective date (End): October 31, 2018
Field of knowledge:Biological Sciences - Zoology
Principal Investigator:Marcos Domingos Siqueira Tavares
Grantee:Rosana Fernandes da Cunha
Supervisor abroad: Ellen E. Strong
Home Institution: Museu de Zoologia (MZ). Universidade de São Paulo (USP). São Paulo , SP, Brazil
Local de pesquisa : Smithsonian National Museum of Natural History, United States  
Associated to the scholarship:17/05663-9 - Taxonomic revision of Narcissia trigonaria Sladen, 1889 (Echinodermata: Asteroidea: Ophidiasteridae): a single species?, BP.MS

Abstract

Narcissia Gray, 1840 currently consists of four valid species: Narcissia ahearnae Pawson, 2007(western Atlantic), Narcissia canariensis (d'Orbigny, 1839) (eastern Atlantic), Narcissia gracilis A.H. Clark, 1916 (eastern Pacific) and Narcissia trigonaria Sladen, 1889 (western and eastern Atlantic). Narcissia trigonaria is the only species recorded from the southwestern Atlantic Ocean to date. Our ongoing morphological studies, resulting from the comparison between N. trigonaria specimens from the Gulf of Mexico, Bahia and São Paulo revealed substantial variability in the distinguishing characters among representatives of different populations. The morphological variations found suggest that N. trigonaria Sladen, 1889 lato sensu actually comprises more than one species. Contrary to what has been said by some, previous authors also have emphasized the morphological discrepancies between specimens of N. trigonaria from different geographic locations. In Narcissia, N. trigonaria is the one with the greatest variation of characters: 1) abactinal and actinal granules either or not forming a mosaic, near or distant to each other; 2) rounded or prismatic abactinal granules; 3) flat or otherwise shaped ambulacra spines; 4) undulated or straight carina ridge; 5) pedicellariae present or absent; 6) abactinal plates tumid or flat. The precarious morphological characterization of N. trigonaria Sladen, 1889, stricto sensu creates difficulties for the proper understanding of the delimitation of the species of the genus Narcissia susceptible to be confused with N. trigonaria str. s. On the other hand, it makes difficult to evaluate the possible existence of different species hidden under the designation N. trigonaria. The Invertebrate Collection of the National Museum of Natural History (NMNH), Smithsonian Institution, stores over 270 specimens, representatives of all species of Narcissia from many different localities. With respect to N. trigonaria there are specimens from almost all localities from where the species has been reported. Access to Narcissia from the NMNH collections is obviously critical to the success of this project. The main goals of the research internship are: perform morphological studies of all the specimens of Narcissia; describe and illustrate the morphological characters relevant to distinguish between species; describe and illustrate relevant morphological variations within species; red escribe and illustrate N. trigonaria Sladen, 1889 str. s. and the morphologically closely related species; evaluate the possible existence of new species currently hidden under N. trigonaria lato sensu. (AU)