2003. Proceedings of the Indiana Academy of Science 1 12(2): 169-174 FRESHWATER HELIOZOA (PROTISTA, HELIOZOA) FROM INDIANA Daniel E. Wujek: Department of Biology, Central Michigan University. Mt. Pleasant. Michigan 48859 USA ABSTRACT. Six taxa of siliceous scale-bearing heliozoa belonging to the genera Acunthocystis. Fin- aciophora, Pterocystis, Raphidocystis and Raphidiophrys were observed from various nc^rthern Indiana freshwater sites. All are new records for Indiana. Keywords: Protista, Heliozoa Previous surveys of Indiana's freshwater scales, the structure of which cannot be dis- protists which utilized electron microscopy cerned clearly by light microscopy. (EM) have reported a diverse flora on the The purpose of this paper is to gi\ e a tax- group of organisms known as the silica-scaled onomic account of Indiana freshwater helio- chrysophytes (Wujek & Swinehart 1995; Wu- zoa observed during EM sur\e\'s for silica- jek & Bechtel 1997). While the taxonomy of scaled chrysophytes (Wujek & Swinehart silica-scale bearing algae of the golden-brown 1995; Wujek & Bechtel 1997) from two north- algae (Chrysophyceae and Synurophyceae) ern counties and Lake Monroe in Monroe has been affirmed on the structure of siliceous County. The only other reports of scaled pro- tists the States using other scales as determined with the electron micro- from United EM than silica-scaled chrysophytes are those oi scope (Takahashi 1978; Asmund & Kristian- Wee & Millie (1983), Wujek et al. (1^)99. sen 1986; Siver 1989; Kristiansen 2002), "the 2002), and Wujek (2003a. b). use of similar criteria in scale-bearing proto- zoa has been slow to develop" (Nicholls METHODS 1983a). Lugol-fixed plankton samples from a w ide Petersen and Hansen (1960) were the first variety of northern Indiana fresh w aters w ere to describe new species of a group of protis- examined using transmission and scanning tans known as heliozoa based on the electron electron microscopy as previous 1\ described microscopy of their scales. Since 1960 contri- in Wujek & Swinehart (1995) and Wujek c<: butions to the literature on this topic has been Bechtel (1997). Observations were made on samples collected at \arious times l'')^)^ and sporadic. Only the studies of Dtirrschmidt in m 1994: in 1993 from nine sites in Noble Count) Chile, New Zealand and Sri Lanka (1985, (Fig. 1) and one site in Whitnex Coinu\ (Wu- 1987a, b); Nicholls and co-workers in Canada jek & Swinehart 1995): and in U)^)4. 14 sam- (Nicholls 1983a, b; Nicholls & Lynn 1984; ples from Lake Monroe (Wujek \: Becluel Nicholls & Diirrschmidt 1985); Croome and 1997) (Table 1). co-workers in Australia (Croome 1986, 1987a. DISCI SSION b, c; Croome et al. 1987); Siemensma & Roi- OBSERVATIONS AND jackers in The Netherlands (Siemensma 1981; Six species belonging lo ihe helio/oan gen- Siemensma & Roijackers 1988a, b); and Mi- era Accuithocysns. Fiiuiciophnra. Ftcrocysiis. krjukov in Russia (Mikrjukov 1993a, b, Raphidocystis, and Raphidiophrxs were ob- served from \arious northen Indiana frc->h- 1994a, b, c, 1995, 1996a, b, 1999. 2000a, b) water sites (Table 1. Figs. 2-~). The hclio/oan have demonstrated that scale structure in he- classitication thai follows conforms lo criteria liozoa possessing siliceous scales is the single ). established b\ Page c'v: Siemensma t U^'-M most reliable taxonomic criterion for this group. Previously much of the taxonomy was Crislidiscoid Helio/oa based on light microscopy of variable cell fea- Numerous, but \ariablc round, bicoinex. tures (e.g., color, size, vacuolation, etc.), or of perforated, and o\erlapping scales co\er the 169 — 170 PROCEEDINGS OF THE INDIANA ACADEMY OF SCIENCE ^^^ Meiry Lea Boundary I I Open Water L: I Wetland . Figure 1 —Map of the Merry Lea Environmental Center, showing the location of the sampling sites in Noble County, Indiana. cells in the genus Pinaciophora. Like all filose 1985), Australia (Croome 1987) and The amoeba, this genus lacks the axonemes and Netherlands and Sweden (Roijackers & Sie- extrusomes observed in the centrohelid helio- mensma 1988). I observed it only once during zoa. my observations (Table 1). Pinaciophora fluviatilis Greeff. (Fig. 2). Centrohelid Heliozoa First reports of this organism for the U.S., un- der the name of Potamodiscus kalbei Gerloff, The genus Acanthocystis contains more were from Mississippi and Ohio (Gaardner et species than any of the other Centrohelida. al. 1976) and Alaska (Manton & Sutherland The genus, erected by Carter (1863), is wide 1979). Gaardner et al. (1976) showed this spe- spread with members occurring in both fresh- cies was incorrectly described as a centric di- water and marine habitats. Cells tend to be atom. It has since been reported from the U.S. round and covered by siliceous spine scales Great Lakes (Wee & Millie 1983) and New with a layer of overlapping body scales. York (Smol 1987). I observed it from only Acanthocystis polymorpha Diirrsch- one site (Table 1). Other EM reports of this midt.—(Fig. 4). Although scales of this or- species include both marine and freshwater ganism were originally illustrated by Taka- habitats in Europe (Thomsen 1978; Belcher & hashi (1959) as occurring in Japan, it was not Swale 1978), Canada (Nicholls 1983b), Ant- until 1985 that Durrschmidt (1985) formally arctica (Takahashi 1981), and The Netherlands described it as a taxon from Chile. Its occur- (Roijackers & Siemensma 1988). rence in Indiana (Table 1) represents the sec- Raphidiophrys intermedia Penard.—(Fig. ond report for this species in the U.S. 3). The cells of the genus Raphidiophrys are Pterocystis fortesca (Nicholls) Siemensma coated with curved, spindle-shaped scales. & Roijackers.—(Fig. 5). Members of the ge- Eighteen species are recognized (Mikrjukov nus Pterocystis (Siemensma & Roijackers 1994c). The only EM reports of this species 1988a), as in the genus Choanocystis, possess are from Canada (Ontario), Chile, New Zea- tangential plate scales and radial spine scales. land and Malaysia (Nicholls & Durrschmidt However, the spine scales are bilaterally sym- ) WUJEK—INDIANA HELIOZOA 17] Figures 2-7.—Transmission electron micrographs of siliceous scales of Indiana liclio/oans. 2. Pinacio- phora fluviatilis, plate scale; 3. Raphidiophrys intermedia, lamellate plate scale: 4. Accinfhccvstis />('/v- morpha, cell with plate and spine scales; 5. Pterocystis forresca, spine scale: 6. A\//'///t/('c \ vr/v mhiuni, plate scale, two large plate scales; 7. Raphidocystis flabellata, circuhu- plate scale. Scale bars = 1 ijim. 1. Table —Indiana locations containing heliozoa. See Wujek c^ Swinehari [ l'-)'^)5) and Wujok A; Hi (1997) for physiochemical data. Taxon Date Localioii Acan thocystis polymorplia 4 May 1994 Lake Monroe (Monroe C\nint\ i Pinaciophora fluviatilis 28 June 1994 Lake Monroe (Monioc C\nini\ i Pterocystis fortesca 29 June 1993 Crooked lake i\\ hule> C\nim\ >: Ke Img Pond. High Lake .<: Reilh Cua\cl Pu iNo le e\nint\ 8 June 1994 Lake Monroe i Monroe C\nini\ ' > Raphidocystis fioheUata 2 July 1993 Lealherleaf Bog i Noble C\nini\ Raph idocystis tub ifera 29 June 1993 Reith Gravel Pit .v^ raniaraek Bog 2 July 1993 Leatherleaf Bog lall Noble (.\nini> ^ Rap/i idioph rys if iteniiedia 2 July 1993 Leatherleaf Boe (Noble Couiu\ i 172 PROCEEDINGS OF THE INDIANA ACADEMY OF SCIENCE metrical, with a cylindrical shaft and membra- Monroe samples, P. Eisner for preparing the nous base which merge into two lateral mem- carbon-coated grids, and G. Williams and A. branous wings that extend for some distance Weber for assistance in the preparation of the along the shaft. photographic plate. This study was in part Originally described from Canada as Acan- funded through a grant from the CMU FRCE thocystis fortesca Nicholls (1983a), Siemens- committee. ma & Roij ackers (1988a) transferred it to the genus Pterocystis and also placed it in syn- LITERATURE CITED with the taxon Acanthocystis panto- onymy Asmund, B.C. & J. Kristiansen. 1986. The genus podecoides Nicholls (1983a). It has since been Mallomonas. Opera Botanica 85:1-128. reported from Australia (Croome 1986). This Belcher, J.H. & E.M.E Swale. 1978. Records from species was the most widely observed in this England of the heliozoan-like organism Pinacio- study (Table 1). phora fluviatilis Greeff and of its scales, ''Pota- Raphidocystis flabellata (Diirrschmidt) modiscus kalbeV Gerloff. Archiv fiir Protisten- kunde 120:367-378. Page & Siemensma.—(Fig. 7). Species in the Carter, H.J. 1863. On a freshwater species Echin- genus Raphidocystis tend to have cells that are ocystidia, Acanthocystis tujfacea, n. sp. et gen.? round and covered with cup-shaped scales in Annual Magazine of Natural History 12:262- addition to many radiate tubular scales. Pre- 264. viously reported from Chile, New Zealand, Croome, R.L. 1986. Observations of the heliozoan Germany, and Canada (Diirrschmidt 1987), it genera Acanthocystis and Raphidocystis from has been recently reported from the Gulf Australia. Archiv fiir Protistenkunde 131:189- Coast of the U.S. (Wujek 2003b). I observed 199. it only from the Leatherleaf bog sample (Table Croome, R.L. 1987a. Observadons of the genera Acanthocystis, Raphidiophrys, Clathrulina and 1). Pompholyxophrys (Protozoa, Sarcodina) from Raphidocystis tubifera Penard.—(Fig. 6). Australian freshwaters. Archiv fiir Protistenkun- Since its original description from France de 133:237-243. (Penard 1904), electron microscopic reports of Croome, R.L. 1987b. Pinaciophora ovalis (Rotos- this species include: Rees et al. from (1980) phaerida, Heliozoea), a new species from Aus- England and Canada; Nicholls & Diirrschmidt tralia. Archiv fiir Protistenkunde 134:343-346. (1985) from Canada, Chile, New Zealand, Croome, R.L. 1987c. Pinaciophora columna n. sp., Malaysia and Sri Lanka; Croome (1986) from P. tasmanica n. sp. and P. apora n. sp., new Australia; Finlay et al. (1988) from England; heliozoeans from Australia, and a report of P. and Wujek (2003b) from the United States fluviatilis Greeff from Antarctica. Archiv fiir Protistenkunde 133:15-20. based on studies using EM. I observed it in Croome, R.L., J. van den Hoff & H.R. Burton. collections from three sites (Table 1).