  Stationary solitary waves are studied in an array of $M$ linearly-coupled
one-dimensional Bose-Einstein condensates (BECs) by means of the
Gross-Pitaevskii equation. Solitary wave solutions with the character of
overlapping dark solitons, Josephson vortex - antivortex arrays, and arrays of
half-dark solitons are constructed for $M>2$ from known solutions for two
coupled BECs. Additional solutions resembling vortex dipoles and rarefaction
pulses are found numerically. Stability analysis of the solitary waves reveals
that overlapping dark solitons can become unstable and susceptible to decay
into arrays of Josephson vortices. The Josephson vortex arrays have mixed
stability but for all parameters we find at least one stationary solitary wave
configuration that is dynamically stable. The different families of nonlinear
standing waves bifurcate from one another. In particular we demonstrate that
Josephson-vortex arrays bifurcate from dark soliton solutions at instability
thresholds. The stability thresholds for dark soliton and Josephson-vortex type
solutions are provided, suggesting the feasibility of realization with optical
lattice experiments.
