Olisthella mimica, 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 : 218

publication ID

https://doi.org/ 10.11646/zootaxa.4242.2.1

publication LSID

lsid:zoobank.org:pub:88B94383-F912-4BBD-B9F0-5642002C496D

DOI

https://doi.org/10.5281/zenodo.6043881

persistent identifier

https://treatment.plazi.org/id/03A78782-FFBB-E464-80F4-4D72FDF7FA6F

treatment provided by

Plazi

scientific name

Olisthella mimica
status

sp. nov.

Olisthella mimica View in CoL n. sp.

( Fig. 10 View FIGURE 10 C–E)

Material examined. Holotype: NIWA 27764 View Materials , NIC Wellington, Stn TAN 0604 About TAN /116, 42.7968° S, 179.9863° E, 950– 1045 m, Graveyard Seamount complex, north-central Chatham Rise, 7 June 2006 GoogleMaps . Other material: NIWA 98222 View Materials , NIC Wellington, Stn TAN 0104 About TAN /389, 42.7832° S, 179.9940° E GoogleMaps – 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.

NIWA

National Institute of Water and Atmospheric Research

TAN

Parc de Tsimbazaza

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