Nongeniculate coralline algae are difficult to identify based solely on morpho-anatomy. To address the systematics of several taxonomically challenging taxa, we analyzed DNA sequences of a short portion (118-296 base pairs) of the 3' end of the rbcL gene from three type specimens. The analyses revealed that Harveylithon munitum (basionym: Lithophyllum munitum), described in 1906 from Cave Cays, Exuma Chain, Bahamas, is conspecific with both Goniolithon accretum and Goniolithon affine, described in 1906 from Sand Key, Florida and in 1907 from Culebra Island, Puerto Rico, respectively. Lithophyllum munitum and G. accretum were described in the same 1906 publication and have equal priority. We have selected the currently accepted and most commonly used name H. munitum to apply to this entity. Comparative analyses of rbcL, psbA, UPA, COI, and LSU sequences from contemporary field-collected specimens revealed that H. munitum currently inhabits mesophotic rhodolith beds in the northwestern Gulf of Mexico, as well as the intertidal zone in the Florida Keys, Honduras, Atlantic Mexico, Caribbean Panama, and Guadeloupe, French West Indies. Species delimitation analyses reveal that the Western Atlantic and Australian H. munitum populations may be separate species. Two new species of Harveylithon from the northwestern Gulf of Mexico and one new species from the southwestern Gulf of Mexico, the Caribbean, and the Red Sea were also identified in the analyses and are described.

Depth range
1- 58 m

Mesophotic “mentions”
7 x (total of 8900 words)

Classification
* Presents original data
* Reports new species
* Focused on 'mesophotic' depth range
* Focused on 'mesophotic coral ecosystem'

Fields
Molecular ecology
Taxonomy

Focusgroups
Algae (Macro, Turf and Crustose Coralline)

Locations
Egypt - Red Sea
Guadeloupe
Mexico - Gulf of Mexico
Panama - Caribbean Sea
USA - Continental Atlantic Ocean
USA - Gulf of Mexico

Platforms
Land-based
Remotely Operated Vehicle (ROV)
SCUBA (open-circuit or unspecified)
Snorkeling