Abyssoecia, Grischenko & Gordon & Melnik, 2018

Grischenko, Andrei V., Gordon, Dennis P. & Melnik, Viacheslav P., 2018, Bryozoa (Cyclostomata and Ctenostomata) from polymetallic nodules in the Russian exploration area, Clarion - Clipperton Fracture Zone, eastern Pacific Ocean-taxon novelty and implications of mining, Zootaxa 4484 (1), pp. 1-91 : 25

Abyssoecia n. gen.

Type species. Abyssoecia elevata n. sp.

Etymology. Latin, abyssus, deep sea, plus - oecia, a common suffix for tubuliporine Cyclostomata . Gender feminine.

Diagnosis. Colony erect to suberect, flabellate to subcalyciform, supported by founding zooids and additional pillars derived from autozooids. No basal kenozooids. Peristomes produced from frontal surface. Gonozooid simple, reniform, not pierced by zooidal peristomes, ooeciostome narrow. Ancestrular zooid suberect with squat imperforate protoecium.

Remarks. The simple form of the gonozooid suggests inclusion in the Oncousoeciidae , used to accommodate tubuliporine cyclostomes having simple gonozooids with terminal cylindrical ooeciostomes ( Taylor & Zatoń 2008). Compared to Abyssoecia n. gen., species of Oncousoecia Canu, 1918 have wholly encrusting colonies with pluriserial branches, and both differ from Microeciella Taylor & Sequeiros, 1982 , in which species are multiserial and flabellate to circular. The ancestrula is wholly adnate in species of Oncousoecia and Microeciella . Among other putative oncousoeciids, Filisparsa d’Orbigny, 1853 differs in having erect, dichotomously branching flattened stems and Discosparsa d’Orbigny, 1853 differs in having umbrelliform, radially symmetrical circular colonies supported by a central stalk, elongate gonozooid (pierced by autozooidal peristomes in at least one species), and elevated subcolonies from the primary colony.

Among living species, the semi-erect ancestrula is exceptional for the family; no information is available concerning the ancestrula in erect Mesozoic taxa that may be related to Oncousoeciidae . Interestingly, although colony form is very different in the species of Pandanipora n. gen., Orectopora n. gen., Discantenna and Abyssoecia n. gen. described herein, the semi-erect to erect ancestrula is very similar, perhaps suggesting either environmental or phylogenetic correlation or both. Erect or semi-erect ancestrulae prior to this study were considered to characterise Articulata and Cancellata, although in one Jurassic species of Microeciella the ancestrular tube is initially semi-erect before descending back down to the substratum ( Taylor & Sequeiros 1982).