After collecting a number of these observations of "elliptical-leaved" Smilax, I'm convinced that nearly all are Smilax auriculata. The conspicuous lateral veins distinguish them from S. laurifolia (and the leaves are smaller). Several examples collected here show a mixture of the elliptical leaves and the more standard "eared" leaves on the same plant (a good illustration is https://www.inaturalist.org/observations/19872386).

I have seen specimens of Smilax havanensis (extreme south Florida) that lack spines on the leaves and look very similar, but the observations in this project range all along the Atlantic and Gulf coasts from North Carolina to Mississippi, most of them well out of range for S. havanensis.

Mine are all empirical observations. I haven't looked closely at the literature to see if this elliptical-leaved form of Smilax auriculata has been formally described.