Resolving the status of Pyriporoides and Daisyella (Bryozoa: Cheilostomata), with the systematics of some additional taxa of Calloporoidea having an ooecial heterozooid
Author
Gordon, Dennis P.
Author
Taylor, Paul D.
text
Zootaxa
2017
4242
2
201
232
journal article
36308
10.11646/zootaxa.4242.2.1
35c61ca1-c858-4f10-baa2-b4b2b72d1454
1175-5326
376356
88B94383-F912-4BBD-B9F0-5642002C496D
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
.