In a journal, what's the difference between an "article" and a "monograph"? This journal issue has contents that are grouped as "article" or "monographic section". What's the difference between these two sections?

I checked the dictionary definition of monograph: "a highly detailed and thoroughly documented study or paper written about a limited area of a subject or field of inquiry", but can't we say the same about the regular articles in this journal? Why do some texts get classified in "article" and some in "monographic section"? To make it more confusing there is also a "Miscellaneous" section in that issue, and I have no idea why it was considered so versus the other texts.
The word monograph is derived from "mono" and "grapho", so the implied literal meaning is "writing on a single subject". Monographic sections are thus sections linked by a single theme, and often only have invited contributions. In the specific journal issue, the theme appears to be related to monuments/architecture from the Almohad Caliphate.

A journal that is clearer about what they mean with monographic sections is 
Kriterion Journal of Philosophy:


  Monographic sections are small collections of original research papers on a specific topic, with an introductory part, that are, in contradistinction to special issues, published as part of a regular issue together with other articles.