Zygopalme, Gordon & Mawatari & Kajihara, 2002

Gordon, Dennis P., Mawatari, Shunsuke F. & Kajihara, Hiroshi, 2002, New taxa of Japanese and New Zealand Eurystomellidae (Phylum Bryozoa) and their phylogenetic relationships, Zoological Journal of the Linnean Society 136 (2), pp. 199-216 : 204

ZYGOPALME GEN. NOV.

Diagnosis

Colony encrusting, uni- to biserial. Autozooids with smooth gymnocystal frontal shield lacking foramina. Zooidal orifices with minute proximolateral indentations and a median suboral suture; no excavations in adjacent gymnocyst. No spines or avicularia. Maternal orifice slightly larger than autozooidal orifice; brooding internal, with a distal ovicell-like kenozooid with a large central perforation; two tiny accessory pores frontally. Ancestrula with membranous frontal wall only, no spines. Interzooidal communications via uniporous mural septula.

Type species: Eurystomella crystallina Gordon (1984) .

Etymology

From zygas (Greek) pair, and palme (f. Greek) shield, alluding to the linear colonial morphology in which zooids may be biserial.

Remarks

Cladistic analysis has tended to highlight the differences between Zygopalme crystallina and other encrusting eurystomellids. Two characters are unique for this species and considered synapomorphies for this monotypic genus. These are the scarcely differentiated proximal corners of the orificial anter, and three kenozooidal foramina (one central, plus two small frontal pores) (see also Cladistic Analysis, below). Autapomorphic characters include the linear colony form and absence of gymnocystal foramina but retention of the median suboral suture. At present the genus is known only from a single station on the southern half of the Kermadec Ridge (33°S), on scleractinian coral at 350 m depth. It was fully described and illustrated by SEM by Gordon (1984).