Errinopora undulata Lindner & Cairns 2011

350-640 m

Colonies lamellate, but wavy in construction resulting in a continuous, thin (1.7–2.0 mm thick), sinusoidal distal edge. Largest colony (USNM 1123528, Fig. 5F) 13 cm tall and 15 cm wide, with a massive basal branch 4.5 × 2.5 cm in diameter; holotype (Fig. 5C) smaller and less intact, measuring 12 cm tall and 11 cm wide, with a basal branch 3.5 × 2.8 cm in diameter. Parasitic spionid worm tubes found in only one colony (USNM 1123528). Coenosteum quite porous, consisting of a reticulum of narrow spiny strips separated by even wider slits, the spines being 10-15 µm in diameter. Coenosteum orange. Dactylopore spines occur equally on both branch faces, but less abundant toward corallum base. Most dactylopores clustered around isolated gastropores in pseudocyclosystems, 3–5 spines surrounding one pore (Fig. 7B). Pseudocyclosystems most common toward base of colony but also occur frequently on more distal parts of corallum where they are interspersed with short, transverse rows of dactylopore spines that border the distal margins of one or more gastropores, their dactylotomes facing upward (abcauline) toward the gastropore; compound dactylopore spines absent. Dactylopore spines fairly short (rarely taller than 0.25 mm), 0.40–0.45 mm in width, and thin walled, the majority of width being the dactylotome; dactylopore spine walls longitudinally ridged. Dactylostyles robust (Fig. 7I–J), up to 0.12 mm in width, consisting of cylindrical elements up to 72 µm in length and 15 µm in diameter. Secondary flush dactylopores common, about 75 µm in diameter. Gastropores circular, flush with coenosteum, and 0.3–0.45 mm in diameter; secondary gastropores about 0.19 mm in diameter. Gastropore tubes short and lack a ring palisade. Gastrostyles lanceolate, the figured style (Fig. 7G) 0.54 mm in height and 0.29 mm in diameter, covered with longitudinal anastomosing spiny ridges. Female ampullae (Fig. 7A–B) irregularly-shaped, flattened hemispheres up to 1.6 mm in diameter. Efferent pores not observed. Male ampullae unknown.

Known only from the Aleutian Islands: Amukta Pass and south of Semisopochnoi Island; 350–640 m (unconfirmed).