S-Nfl-^t3.-(o.:i.el DO NOT ci^t^u^;2?!^''-^°°^ B R E V I O 'R A HARVARD Miiseitanti of Comparative ^oofS'J^ Cambridge, Mass. 3 April, 1970 Number 347 DESCRIPTION, OSTEOLOGY AND RELATIONSHIPS OF THE AMAZONIAN CYPRINODONT FISH FLUVIPHYLAX PYGMAEUS (MYERS AND CARVALHO) Tyson R. Roberts^ Abstract. The minute Amazonian cyprinodontid Fluviphylax pygmaeus (Myers and Carvalho) is redescribed and its osteology worked out based on material obtained by the Expedigao Permanente da Amazonia (EPA). Its relationships apparently lie either with the Procatopodinae (a subfamily otherwise restricted to Africa) or with the Fundulinae, and not with the Rivulinae. A new subfamily, Fluviphylacinae, is proposed for it. The very smallest egg-laying and live-bearing cyprinodonts occur in Amazonia, whereas the largest ones are found in habitats geographically or ecologically isolated from rich fish faunas. ACKNOWLEDGEMENTS I wish to thank Prof. George S. Myers, Division of Systematic Biology, Stanford University, and Dr. Neal R. Foster, Department of Limnology, Academy of Natural Sciences of Philadelphia, for critically reviewing the manuscript of this paper and offering help-ful suggestions. INTRODUCTION This paper deals with an almost unknown but widely distributed Amazonian cyprinodontid fish of minute size, Fluviphylax pyg-maeus (Myers and Carvalho). Prof. George S. Myers of Stanford University kindly supplied the following information about its origi-nal discovery. In 1942-44, when Myers was working at the Museu Nacional in Rio de Janeiro in collaboration with Sr. Antenor Leitao de Carvalho, Naturahsta of the Museu, a man named Alexandre Parko was collecting for the Museu in Amazonia. Although pri-marily concerned with insects, Parko obtained a few vertebrates, including the type of a remarkable toad, Bujo dapsilus Myers and 1 Assistant Curator of Fishes, Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts 02138.