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
Olisthella mimica
n. sp.
(
Fig. 10
C–E)
Material
examined.
Holotype
:
NIWA
27764
, NIC
Wellington
,
Stn
TAN
0604
/116,
42.7968° S
,
179.9863° E
,
950– 1045 m
, Graveyard Seamount complex, north-central Chatham Rise,
7 June 2006
.
Other
material
:
NIWA
98222
, NIC
Wellington
,
Stn
TAN
0104
/389,
42.7832° S
,
179.9940° E
– 42.7803° S, 179.9895° E,
870–1000 m
, Scroll Seamount, Graveyard Seamount complex,
21 April 2001
.
Etymology.
Latin
mimicus
, imitative, alluding to the similarity of this species to
O. occlusa
n. sp.
Description.
Colony unilaminar, weakly pluriserial, with zooids contiguous or slightly disjunct, maximum spread
2 mm
, hence small and spot-like. Autozooids more or less elongate-oval to subpyriform [ZL 754–945 (825); ZW 478–645 (577)]. Gymnocyst encircling entire autozooid, generally narrow throughout but may be a little broader proximally or proximolaterally. Cryptocyst and opesia encircled by a continuous raised rim that is smooth or weakly granular [CrL 556–689 (623); CrW 389–522 (465)]; cryptocystal shelf present, but relatively narrow, almost flat where it borders the opesia, gently sloping towards opesia, barely attenuating in width until it reaches the orificial area, entirely smooth or with weak granulation just within the rim. Opesia more or less narrowly elongate-oval, generally slightly broader proximally but also virtually parallel-sided in some zooids [OpL 421–528 (469)]. Articulated pericryptocystal spines
10–15 in
number, all of nearly equal thickness including the distalmost six spines bordering the orifice in an arcuate series; 2–8 additional spines on the surrounding gymnocyst, the maximum number of spines seen on any one zooid = 22. Avicularia, ooecia and ancestrula lacking.
Remarks.
Olisthella mimica
n. sp.
resembles
O. occlusa
n. sp.
in having a similar colony form (a mix of contiguous and slightly disjunct autozooids) and opesial shape, but differs in having half the total number of spines (12–22 vs 23–44) per autozooid, and a smoother, narrower cryptocyst. Occluding kenozooids have not yet been seen in
O. mimica
n. sp.
Distribution.
Endemic to the
New Zealand
EEZ; known only from the Graveyard Seamounts at
870–1045 m
, where it encrusts gravel-sized clasts.