Pseudothelogorgiidae, Samimi-Namin & McFadden, 2025

Samimi-Namin, Kaveh & McFadden, Catherine S., 2025, Integrative phylogenomic and morphological evidence for Pseudothelogorgiidae fam. nov., with a redescription of Pseudothelogorgia hartogi (Octocorallia, Malacalcyonacea), ZooKeys 1261, pp. 201-221 : 201-221

Pseudothelogorgiidae fam. nov.

Type genus.

Pseudothelogorgia van Ofwegen, 1994 .

Excluded from Keroeididae Kinoshita, 1910 (see van Ofwegen 1990, 1994).

Included genus.

Pseudothelogorgia van Ofwegen, 1994 .

Diagnosis.

Octocorals with a skeletal axis of consolidated sclerites embedded within a proteinaceous or calcitic matrix with hollow central core (no cross-chambering observed). Axial sclerites smooth, fused, densely packed around the central core forming pavement-like surface layer. Colonies arborescent, branching irregularly to dichotomously; branches cylindrical. Polyps monomorphic, non-retractile into the thin coenenchyme, arranged spirally along branches. Longitudinal furrows present along stem and branches. Polyps with tuberculate rods and spindles arranged as points; collaret absent; tentacles with rods; pharyngeal sclerites absent. Sclerites of the coenenchyme are rods and spindles with simple or complex tubercles. Capstans present in coenenchyme of the main stem. Azooxanthellate.

Remarks.

The genus Pseudothelogorgia and its type species ( P. hartogi ) were previously included in Keroeididae Kinoshita, 1910 ( van Ofwegen 1990, 1994). However, recent molecular phylogenetic analyses (this study; Quattrini et al. 2024) and unique morphological features demonstrate that Pseudothelogorgia represents a distinct lineage, supporting its exclusion from Keroeididae and the establishment of Pseudothelogorgiidae fam. nov.

Pseudothelogorgiidae fam. nov. differs from Plexauridae in having a thin, translucent stem coenenchyme containing capstans, rods, and spindles with complex tubercles, and an axial cortex of fused sclerites surrounding a hollow core, rather than the thick, loculated coenenchyme with separate inner and outer layers and unfused axial cortex sclerites typical of Plexauridae .

Distribution.

Indo-West Pacific, shallow to mesophotic ( 18–207 m depth).