Portuguese to English Social Sciences Genealogy

This is in a document listing a group of people who emigrated from the U.S. to Brazil in the 1860s. Casal is entered before a man's name, not in conjunction with a "couple" but also not including the full term "cabeca de casal". The way it reads it would not make sense to simply mean "couple", but I'm not sure if I'm missing something here. Please let me know.

Here's a sample, with names changed:

Os trezes membros fundadores da igreja...foram os seguintes: Rev. Matthew Boyd e Emily Boyd, Rev. William R. Frank e Elize Frank, casal J. B. Jones e filhas Sophia Jones e Martha H. Jones, William Jefferson, Sarah P. Jefferson e filha Sarah A. Jefferson, e casal Bradford Boyd.