We introduce the oriented Brauer-Clifford and degenerate affine oriented
Brauer-Clifford supercategories. These are diagrammatically defined monoidal
supercategories which provide combinatorial models for certain natural monoidal
supercategories of supermodules and endosuperfunctors, respectively, for the
Lie superalgebras of type Q. Our main results are basis theorems for these
diagram supercategories. We also discuss connections and applications to the
representation theory of the Lie superalgebra of type Q.Comment: 37 pages, many figures. Version 3 replaces the partial results from
the previous versions with a proof by the first author of a basis theorem for
cyclotomic quotients at all levels. Various other minor corrections and
revisions were mad