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640 New Zealand Journal of Marine and Freshwater Research, 1998, Vol. 32Fig. 1-5 Drawings showing general features of phylactolaemate bryozoans. Fig. 1 Single zooid of Fredericellashowing the circular lophophore typical of this species (other phylactolaemate bryozoan genera have U-shapedlophophores). s = a developing statoblast. Scale bar = 400 um. Fig. 2 Statoblast of F. sultana showing elongateshape, smooth surface, and lack of ornamentation. Fig. 3 Single statoblast valve of F. australiensis showing roundedshape and characteristically thickened rim. Fig. 4 Floating statoblast of Plumatella emarginata showing the flatdorsal side with small fenestra. Fig. 5 Floating statoblast of P. repens rugosa, dorsal side, showing proportionstypical also of P. repens typica and P.fungosa. Scale bar = 65 um for Fig. 2-5.thorough survey. Some species were undoubtedlyoverlooked, and large regions of New Zealand wereentirely missed for lack of time and resources.Our collection was supplemented with twoplumatellid specimens received by the National Instituteof Water & Atmospheric Research Ltd(NIWA) and made available to us. These were collectedin January and February 1995.MATERIALS AND METHODSMost specimens were taken from substrates selectedby hand in shallow water. The two NIWA specimenscame from blocked pipes on farms in Patea(Taranaki) and Brighton (Otago, near Dunedin).Although treatment methods varied, most livingspecimens were narcotized with menthol, fixed informalin, and preserved in 70% ethyl alcohol. Atsoft-bottomed sites we passed samples of sedimentthrough brass screens (mesh diameter 250 (im) tocapture any benthic statoblasts of the FamilyLophopodidae. We measured water temperaturewith an alcohol thermometer, pH with a glass electrode,and dissolved solids with a portable conductivitymeter. Statoblasts of all plumatellid and mostfredericellid species were later examined by scanningelectron microscopy (SEM) to verify characteristicsurface topology. Most of the specimens arecurrently in the collection of the primary author.
Wood et al.— Freshwater bryozoans of New Zealand 641RESULTSAltogether we visited 46 sites in the North and SouthIslands, including rivers and lakes of various sizesand trophic conditions. Bryozoans were found at 39of these sites, including at least one species not previouslyreported from New Zealand (Tables 1 and2, Fig. 6). Each species is described below in orderof decreasing frequency of occurrence.Fredericella sultana (Blumenbach, 1779)(Fig. 1,2)Fredericella sultana was found at 62% of all siteswhere bryozoans occurred, making it the commonestspecies encountered. When Dendy (1906) firstreported this species at Christchurch, Annandale(1911) had not yet described F. indica. The twospecies are distinguished only by their statoblasts,which are smooth in F. sultana but deeply pitted inF. indica (Wood & Backus 1992). Both species arewidely distributed: F. sultana in Europe and Asia(Lacourt 1968), F. indica in India (Annandale 1911),North America (Wood & Backus 1992), and recentlydiscovered in Germany (Massard & Geimer 1995).We confirm that the fredericellid species in NewZealand is indeed F. sultana.Unfortunately, statoblasts were scarce in the NewZealand material, even in the very large colonies.Nearly half of our specimens had no statoblasts atall and thus cannot be positively identified, althoughwe expect they are the same species as our morecomplete specimens. All of the statoblasts we examinedbear a very faint pebbly texture of slightly raisedbumps. These are easily visible using reflected lightmicroscopy on dry specimens. However, we judgethese to be not significantly different from typicalF. sultana statoblasts from Europe and Asia.Table 1 Distribution of bryozoan species on North Island, New Zealand, with data on water temperature, pH, andtotal dissolved solids (TDS). FSUL = Fredericella sultana, PART = Paludicella articulata, PEMA = Plumatellaemarginata, PX = unnamed plumatellid, PTYP = Plumatella repens typica, PRUG = Plumatella repens rugosa, PREP= specimens lacking sufficient floatoblasts to distinguish the specific form.Region and siteTemp. (°C)pHTDS (uS)SpeciesAucklandAuckland, Auckland DomainHunua Falls, 2 km NE HunuaManawatu-WanganuiMangaone River, 6 km S KaitawaMangawhero River, 15 km SW OtokoMt. Bruce Centre, 9 km SW EketahunaOroua River, 3 km E FeildingPa Creek, 15 km S PahiatuaMangawhero River, 3 km SW OreoreTaranakiFarm Pond, near PateaWaikatoOkere Falls, 16 km NE RotoruaLake Atiamuri, 22 km SE TokoroaL. Otamangakau channel, 8 km NW TurangiLake Otamangakau, 14 km E TurangiLake Rotoaira outlet, 8 km NW TurangiOhau channel, 14 km NE RotoruaLake Tarawera, 14 km SE RotoruaWaikato River at HamiltonHamilton, university campusLake Karapiro, 6 km SE CambridgeLake Rotoaira, 12 km WSW TurangiWellingtonLake Wairarapa, 14 km WNW MartinboroughLake Wairarapa, 25 km WSW MartinboroughWellington, Botanic Gardens_222121_281819-2323216920242322-23-1916-• —8.18.77.7_8.07.28.0-7.87.68.78.77.28.48.67.6-8.2-7.77.3-_134320-152716-2019151615215023-18-8130-PTYPFSULPXFSUL, PRUGPEMA, PRUGPREPFSULFSULPRUGFSULFSUL, PRUGPEMA, PRUGPEMA, PRUGFSULFSUL, PRUGFSULFSUL, PREPPEMA, PRUGFSULPRUGFSULPRUGPEMA, PRUG
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