Pandanipora, 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 : 8-9

Pandanipora n. gen.

Type species. Pandanipora helix n. sp.

Etymology. Alluding to the angiosperm genus Pandanus Parkinson , in which branches are characteristically supported by vertical prop roots, plus - pora, a common suffix for cyclostome bryozoans. Gender feminine.

Diagnosis. Colony uniserial, linear to helicospiral, semi-erect to erect, supported above substratum by proplike extensions, generally one per zooid. Autozooids comprising continuous proximal portions that form axis of colony, plus erect peristomial tubes. Zooidal budding via symmetrical median partition originating from floor of axial part of parent zooid; proximal parts of zooids frontally overlapping. Autozooidal pseudopores tiny, simple, sparse. Gonozooid unknown. Ancestrula erect, tubiform, with swollen, squat, imperforate protoecium, its distal peristome curving.

Remarks. Pandanipora n. gen. differs from typical stomatoporiform tubuliporines in being wholly non-adnate and supported above the substratum by props, typically one per zooid, as well as strictly uniserial and either unbranching or with a rare short bifurcation near the colony origin. Stomatopora Bronn, 1825 and related encrusting genera have an adnate ancestrula. Insofar as the ancestrula of Pandanipora n. gen. is erect and tubiform, it resembles that of Peristomatopora Moyano, 1991 , which has the same form, i.e. a small swollen, squat protoecium, plus a curving erect peristome. On this basis, Peristomatopora would seem to be unrelated to Stomatopora , but the phylogenetic relationships of these and associated genera are poorly known. Taylor (1993) retained use of the family Stomatoporidae Pergens & Meunier, 1887 , whereas Ross & Ross (1996) merged Stomatoporidae in the later-named Diastoporidae Gregory, 1899 , itself based on a genus of controversial status in which the gonozooid is typical of that in the Plagioeciidae Canu, 1918 ( Taylor & Wilson, 1999). Hayward & Ryland (1985) and Moyano (1991) included Stomatopora and/or associates in Oncousoeciidae Canu, 1918 . Hayward & Ryland (1985, p. 18) illustrated a gonozooid in extant Stomatopora gingrina Jullien, 1882 that has the same form as that illustrated in Peristomatopora by Moyano (1991), which begs the question, which character is phylogenetically more significant—the form of the ancestrula or the incubation chamber? The gonozooid in Pandanipora is so far unknown.

Do skeletal ultrastructural characters provide a clue? Moyano (1991) gave no such information concerning his new stomatoporine taxa. Taylor & Weedon (2000) reported that “ Stomatopora ” sp. (with an adnate ancestrula) and all studied articulates (with an erect ancestrula) apart from Crisulipora have a fabric suite that includes hexagonal semi-nacre, which is not found in Pandanipora n. gen. Instead, Pandanipora exhibits a predominantly distally imbricated foliated fabric typical of rectangulates, some cerioporines and some tubuliporines. The question remains open, but Pandanipora appears distant from articulates and stomatoporines (the latter admittedly based on limited data) and is probably closer to some other tubuliporines.