Copy or variant of a Greek statue of the 3rd or 2nd century B.C.
The figure is shown in a spiraling upward movement, perhaps in dance or blowing on an instrument. Tritons, with their long fish tails, often are shown with wild hair and powerful torsos. This could be such a sea creature, possibly blowing on a conch shell.
Richter, Gisela M. A. 1954. Catalogue of Greek Sculptures. no. 206, p. 106, pl. 146, Cambridge, Mass.: Harvard University Press.
Kossatz-Deissmann, Anneliese, Brigitte Servais-Soyez, Fulvio Canciani, Giovannangelo Camporeale, Hans Peter Isler, Ingrid Krauskopf, Odette Touchefeu-Meynier, Marcel Le Glay, and Dr. Jean-Charles Balty. 1997. Thespiades-Zodiacus, Lexicon Iconographicum Mythologiae Classicae, Vol. 8. Tritones, no. 46, Zürich: Artemis Verlag Zurich und Munchen.