Overpartitions related to the mock theta function ?(q)

It was recently shown that q?(q), where ?(q) is one of the third order mock theta functions, is the generating function of p?(n), the number of partitions of a positive integer n such that all odd parts are less than twice the smallest part. In this paper, we study the overpartition analogue of p?(n), and express its generating function in terms of a 3?2 basic hypergeometric series and an infinite series involving little q-Jacobi polynomials. This is accomplished by obtaining a new seven parameter q-series identity which generalizes a deep identity due to the first author as well as its generalization by R.P.~Agarwal. We also derive two interesting congruences satisfied by the overpartition analogue, and some congruences satisfied by the associated smallest parts function.