Genus Gigantopora Ridley, 1881

Type species. Gigantopora lyncoides Ridley, 1881

Stenopsis Canu & Lecointre, 1925. Nomen nudum.

Stenopsis Canu & Bassler, 1927 (preoccupied). Type species: Hippothoa fenestrata Smitt, 1873.

Stenopsella Bassler, 1952. Type species: Hippothoa fenestrata Smitt, 1873.

Diagnosis. Colonies encrusting or erect.Zooids with convex,granular,or nodular frontal walls with small pseudopores. Primary orifice oval, with a pair of proximolateral condyles; spines absent. Peristome tubular, obscuring the primary orifice, often with proximal spiramen and with single or paired lateral adventitious avicularia. Vicarious avicularia absent. Ovicell hyperstomial, acleithral, with the same morphology as the frontal wall.

Remarks. Gigantopora was originally established to include Gigantopora lyncoides and Hippothoa fenestrata. Later, Gi. lyncoides was selected as the type species (Canu & Bassler 1917). The historical taxonomic uncertainty of Hippothoa fenestrata has been discussed by Di Martino (2022), who provided a redescription of the Smitt’s type material and synonymized Stenopsella Bassler, 1952 under Gigantopora.

Brown (1952) synonymized Gephyrophora Busk, 1884 under Gigantopora, through the selection of the lectotype of Gephyrophora polymorpha Busk, 1884. This synonym has been accepted by several authors, including Gordon (1984), Hayward & Cook (1979, 1983), and Florence et al. (2007). However, Brown (1952) described endozooidal ovicells in Busk’s specimens, which was also later noted and illustrated by Florence et al. (2007) in colonies from near the type locality, but here considered distinct from the hyperstomial ovicells of Gigantopora. Based on the phylogenetic analysis presented by Orr et al. (2022), Gephyrophora and Gigantopora were not monophyletic and were kept as distinct genera, a decision that is also supported here by the morphological differences observed in species of these two genera.