Bryobrownius, Gordon, Dennis P. & Taylor, Paul D., 2017

Gordon, Dennis P. & Taylor, Paul D., 2017, Resolving the status of Pyriporoides and Daisyella (Bryozoa: Cheilostomata), with the systematics of some additional taxa of Calloporoidea having an ooecial heterozooid, Zootaxa 4242 (2), pp. 201-232 : 221-222

Genus Bryobrownius n. gen.

Diagnosis. Colony encrusting, multiserial, small and spot-like; autozooids arranged contiguously in quincunx. Gymnocyst quite well developed, continuous around zooid. Cryptocyst and opesia surrounded by a distinct raised rim, the cryptocystal shelf fairly extensive, sloping toward opesia, attenuating laterally. Opesia longer than wide, constricted in middle. Oral and pericryptocystal spine bases present; no accessory gymnocystal spines. Avicularia interzooidal, rostrum long, narrow, acute, apparently lacking pivot bar. Ooecium hyperstomial, smooth with median suture line; ooecial kenozooid visible distally, with circular area. Ancestrula small, circular, with pericryptocystal spines.

Type species. Amphiblestrum willetti Brown, 1952 ; monospecific.

Etymology. Honorific for David Alexander Brown (1916–2009), a notable Scottish-born geologist who described many species of bryozoans from Australasia; gender masculine.

Remarks. Bryobrownius n. gen. differs from the calloporid genus Amphiblestrum Gray, 1848 in several significant characters, viz a raised ridge separating the cryptocyst from a moderate to well-developed gymnocyst, pericryptocystal spines, an ooecium lacking a frontal excavation, and an ooecial kenozooid with a frontal foramen. As in Pyriporoides and Olisthella n. gen., the ooecia in Bryobrownius n. gen. are budded from a kenozooid, not the distal autozooid, but Pyriporoides has caudate uniserial zooids, Olisthella n. gen. has concealed ooecia and lacks interzooidal avicularia. Megapora has frontally visible ooecial kenozooids but differs from Bryobrownius in lacking pericryptocystal spines, avicularia and a distinct pyriform ridge cleanly separating cryptocyst from gymnocyst.

The characteristics of Bryobrownius n. gen. invite comparison with the Pyrisinellidae . Di Martino & Taylor (2012) included four genera in this family, one of them, Megapora , provisionally. Like Bryobrownius , Pyrisinella Di Martino & Taylor, 2012 and Setosinella Canu & Bassler, 1933 have interzooidal avicularia, but those in Pyrisinella have complete pivot bars (equivocal in Setosinella ), the opesia is trifoliate in Pyrisinella and transversely D-shaped in Setosinella and the cryptocyst is opesiulate in the latter. Spinisinella Di Martino & Taylor, 2012 has spinose ooecia and no avicularia. We would argue that one major difference that separates Bryobrownius and Megapora from Pyrisinella , Spinisinella and Setosinella is the fact that, in the latter three genera, the ooecium is budded from the distal autozooid, not a kenozooid. For this reason, Bryobrownius n. gen. and Megapora seem allied with Pyriporoides and Olisthella n. gen., as is also Apiophragma Hayward & Ryland, 1993 (see below).

Distribution. Known only from the earliest Oligocene at the type locality in North Otago, South Island, New Zealand.