Species guide

The Atlantic longarm octopus (Macrotritopus defilippi) is a small- sized octopus (mantle length or ML < 60 mm), slender-bodied, with long, tendril-like arms that extend three to eight times its mantle length, and is a sand-dwelling species notable for its burrowing behavior and mimicry while swimming (Guerrero-Kommritz & Rodriguez-Bermudez, 2019; Hanlon et al., 2010).

The Brazilian reef octopus (Octopus insularis) is morphologically similar to O. americanus. This species is differentiated via the red and white reticulated pattern on the ventral side of the arms (C. E. O’Brien et al., 2021). They can also be differentiated by their deimatic displays, which in O. insularis features a white eye encircled by a pale ring and dark eye bar.

The Caribbean reef octopus (Octopus briareus) is moderate sized (ML < 120mm), with long arms (4 to 6 times mantle length), and characteristically loose webbing that is both deep and thin (almost billowing), which it uses to envelope coral heads, rubble, and prey, as well as an iridescent blue-green color pattern (Jereb & Roper, 2005).

The common American octopus (Octopus americanus (prev. O. vulgaris)) is a cryptic member of the Octopus vulgaris species complex (Avendaño et al., 2020). This species is medium to large in size (ML 80–132 mm), and muscular with a broad, oval mantle and short, more robust arms (4–5 times mantle length) and prefers rocky substrate and sheltered dens.