Disporella minutissima, Gordon & Taylor, 2010

Gordon, Dennis P. & Taylor, Paul D., 2010, New seamount- and ridge-associated cyclostome Bryozoa from New Zealand, Zootaxa 2533 (1), pp. 43-68 : 63

Disporella minutissima n. sp.

( Fig. 11 E, F )

Material examined. Holotype: NIWA 61258 , from cruise TAN0104, Stn 3, 42°45.48– 42°45.18’S, 179°59.47– 179°59.54’ W, “Graveyard” Seamount, Chatham Rise, 943–1097 m depth, collected 15 April 2001.

Distribution. “Graveyard Seamount Complex”, north-central Chatham Rise, New Zealand, 943–1097 m.

Etymology. Latin, superlative of minutus, small.

Description. Colony exceedingly tiny, comprising just five autozooids and a central gonozooid, supported on a smooth, short pedestal. Typical cancelli lacking, but five small pores present, one basal to each zooidal aperture. Peristomes relatively thick-walled, with up to five short, blunt processes; all exterior surfaces of zooidal disc relatively coarsely granular. Brood chamber small, oval, its granular surface merging into that of the peristomes that surround it, the ooeciostome circular, smooth with a thin rim.

Remarks. This species is so far known only from the type locality, which yielded a single fertile colony. It is unquestionably the smallest cyclostome species known ― in fact the smallest calcified bryozoan known ― and the entire colony could easily fit inside an individual zooid of most cheilostome species; its individual zooids are smaller than the mature zooids of the interstitial ctenostome bryozoan Monobryozoon ambulans (see Hayward 1985) which has minute colonies with only one autozooid.

The generic attribution is uncertain. The zooids of D. minutissima closely resemble those of D. minicamera but the smooth basal pedestal is lacking in this species. The pedestal, which is exterior-walled, may be homologous with the conical peduncle of the Cretaceous–Miocene genus Lichenopora (Gordon & Taylor 1997) . The ooeciostome of D. minutissima is round, quite unlike the broad transverse opening in D. minicamera .

Figures

FIGURE 11. A–D. Disporella minicamera n. sp. (TAN0104 Stn 3). A, B, whole colonies with globular brood chambers; C, infertile colony; D, brood chamber with broad transverse ooeciostome. E, F. Disporella minutissima n. sp. (TAN0104 Stn 3); E, close-up of ooeciostome; F, whole colony with short, smooth base and central brood chamber with ooeciostome.