This paper presents the distributed transport for sensor networks (DTSN), a novel reliable transport protocol for convergecast and unicast communications in wireless sensor networks (WSNs). In DTSN, the source completely controls the loss recovery process in order to minimize the overhead associated with control and data packets. The basic loss recovery algorithm is based on selective repeat ARQ, employing both positive and negative acknowledgements. DTSN is able to detect when all packets of a session are lost, besides scattered gaps in the packet sequence. Caching at intermediate nodes is used to avoid the inefficiency of the strictly end-to-end transport reliability TCP-like model, commonly employed in broadband networks. Reliability differentiation is achieved by means of the smart integration of partial buffering at the source, integrated with erasure coding and caching at intermediate nodes. The simulation results attest the effectiveness of both the full reliability and the reliability differentiation mechanisms in DTSN.