Nova Hedwigia 49 3-4 369-380 Stuttgart, November 1989 Thecal morphology of the dinoflagellate Peridinium gutwinskii AndrCs Boltovskoy Instituto de Limnologia "Dr. R.A. Ringuelet" Casilla de Correo 712, 1900 La Plata, Argentina With 4 plates and 1 table Boltovskoy, A. (1989): Thecal morphology of the dinoflagellate Peridinium gutwinskii. - Nova Hedwigia 49: 369-380. Abstract: Peridinium gutwinskii, an uncommon freshwater dinoflagellate known from Indonesia and Africa, is reported from Corrientes province, Argentina. Entire thecae and dissociated plates are de- scribed and illustrated by means of light and scanning electron microscopy providing new information or shape, surface ornamentation, thecal tabulation including the cingulum and sulcal and apical complexes. growth bands and plate overlapping pattern. The intraspecific variability, similarities with closely related species and global distribution are discussed. The specimens from Corrientes has a penta dorsal platt arrangement and its complete plate formula is 2x, 4 ', 3a, 7 ' ', 5c, 5s, 5 ' ', 2 ' ' ' '. Resumen: Peridinium gutwinskii, un dingoflagelado de agua dulce poco comun conocido para Indonesie y Africa, es mencionado para la provincia de Corrientes, Argentina. Tecas y placas disociadas se descri. ben e ilustran mediante microscopia 6ptica y microscopia electr6nica de barrido, obtenikndose informa- ci6n original sobre su morfologia, ornamentaci6n, tabulaci6n general, cingular, sulcal y del poro apical, bandas de crecimiento y forma de imbricaci6n de la placas. Se discuten la variabilidad intraespecifica, las semejanzas con especies estrechamente emparentadas y la distribuci6n mundial. Los ejemplares de Corrientes tienen la disposici6n de las placas dorsales de la epiteca del tilpo penta y su f6rmula tabular completa es 2x, 4 ', 3a, 7 ", 5c, 5s, 5 ' ' ', 2 " ' '. Introduction Peridinium gutwinskii Woloszynska (1912) is a rare freshwater dinoflagellate re- ported from tropical eutrophic environments: Java, Sumatra (Woloszynska 1912, 1923, 1930; Ruttner 1952), Borneo (Lindemann 193 l), Madagascar (Lef2vre 1932) and Ivory Coast (CoutC & Iltis 1984). This paper reports its presence on the American continent, in the north-western part of the province of Corrientes, Argen- tina, near Colonia Garabi (aprox. 28" 12 'S, 55" 48 ' 'W), where it was collected in April 1975 in a shallow swamp with pH 6.5-6.8 (Vucetich 1978) and an associes of the macrophytes Lemna valdiviana, Azolla caroliniana, Ricciocarpus natans, and Spirodela intermedia (N. Tur , pers. comm .). Scientific contribution no 395 from Instituto de Limnologia "Dr. Raul A. Ringuelet". 0029-5035/89/0049-0369 $3.00 6J I989 J . Cramer in der Gebruder Bornlraeger Verlagsbuchhandlung. D-1000 Berlin . D-7000 Sluttgart 369 The thecal structure of P. gutwinskii including cingular and sulcal tabulations, is de- scribed and illustrated by means of light and scanning electron microscopy. Its intraspecific variability is discussed as well as the similarities with closely related species and global distribution. Material and methods Specimens were isolated from the formaldehyde-fixed samples with the aid of a capillar micropipette. Line drawings of the thecae were performed by means of a camera lucida from preparations mounted on gelatin-glycerin. Microdissections between slide and cover slip were done with or without prior treatment with diluted sodium hypochlorite. Thecae were stained with iodinated hydroiodic acid (which denotes thickened areas and also helps to separate the plates). Unstained plates were observed with Nomarski's interference contrast illumination. Materials for SEM were isolated, rinsed with distilled water and freeze dried. Results Shape and tabulation: The specimens of P. gutwinskii from Corrientes have a protoplasm with dark chloroplasts and a lighter nucleus located slightly above the cingular plane. The nucleus is elongated transversally and bent, with its convex side facing the apex (figs. 2, 3). The theca is nearly biconical, the epitheca being taller than the hypotheca. Its length is larger than its width, and it is slightly flattened dorsoventrally. At the apex the neck is reduced to a small remnant formed by the edges of the plates which surround the apical area. The antapex bears a posteriorly directed spine (figs. 1-3, 6, 8, 11, 12, 14). The cingulum, which is excavated and bordered by cingular lists, has a descending helical trajectory; its extremes are displaced ventrally 2.5-3 cingular heights. The sulcus extends in the epitheca, broad- ens posteriorly and is bordered by poorly developed lists (figs. 1, 6, 8, 14). The di- mensions based on 30 specimens are as follows: 65-85 pm in length (excluding the posterior spine), 53-76 pm in transversal diameter and 45-68 pm in thickness. Cysts of P. gutwinskii were not registered. For the basic plate nomenclature the Kofoidian system is adopted in the following description (Kofoid 1909); the abbreviations of the sulcal plates (initials of their Latin names) and apical pore platelets are used as by Balech (1974 and elsewhere). The theca of P. gutwinskii is composed by the following plates: two apical pore platelets (x), four apical plates (I), three interalary plates (a), seven precingular plates ( ' I), five cingular plates (c), five sulcal plates (s), five postcingular plates Plate 1: Peridinium gutwinskii from a swamp in Corrientes, Argentina. - Fig. 1: Ventral view showing a sinuous refractive area at the right margin of the sulcus. Fig. 2: Dorsal view showing the position and shape of the nucleus (N). Fig. 3: Left lateral view showing the nucleus (N). Fig. 4: Apical view showing the right-penta arrangement of plates. Fig. 5: Antapical view. Fig. 6: Ventral view of a specimen with broad intercalary bands. Fig. 7: Sulcal plates and their relationships with adjacent plates: anterior sulcal plate (sa), left sulcal plate (ss), right sulcal plate (sd), posterior sulcal plate (sp), posterior accessory sulcal plate (spa). Inset, sulcal anterior plate folded, with its in situ appearance. ( ' ' '), and two antapical plates ( ' ' ' '), pl. 1, fig. 1-7). Thus, the complete plate formula is 2x, 4 ', 3a, 7 ' ', 5c, 5s, 5 ' ' ', 2 ' ' ' '. The rhombic (orthoperidinoid) first apical plate is twice as high as wide and reaching the apex. Plate 7 ' ' is very charac- teristic because its posterointernal angle is elongated into a lobe extending towards the sulcus, which gives the impression of a slight cingular overcrossing (figs. 1, 6, 8, 14). Due to this extension of plate 7 ' ' the sulcus is very narrow and deep between the ends of the cingulum. The second intercalary plate (2a) is pentagonal (penta) and is displaced toward the right in such a way that 3a does not contact 4 ' ' (figs. 2, 4, 10, 12, being these characters constant features for the population described. On the hypotheca the antapical plates are dorso-ventrally elongate and 1 ' ' ' ' is somewhat larger than 2 ' ' ' '. Surface structure: The surface relief ornamentation of the main plates is a reticulum of polygonal alveoles perforated by pores, with rounded granules at the nodes of the mesh. On the posterointernal lobe of plate 7 ' ' there are higher numbers of pores and the meshwork is less prominent (figs. 8, 18, 23). The lists which border the cingulum and the sulcus originate from the margin of adcingular plates. These lists are supported by ribs representing prolongations of the surface reticulum. The remaining plate margins are bordered by sutural ridges. The antapical spine, at high magnification and in lateral view, appears to be like a spur with two triangular tips: the ventral one is about 1 pm in length, while the dorsal reaches 3 to 7 pm (figs. 19, 20). This structure emerges from the antero- internal angle of plate 2 ' ' ' ' and is an outgrowth of its marginal ridge (figs. 2, 6, 8, 9, 24). Its origin is similar to that of the antapical lists in Peridinium willei Huitfeld- Kaas, P. bipes Stein, P. Iimbatum (Stokes) Lemmermann etc., which also are out- growths of the marginal ridges. Apical pore: Two platelets are related to the apical area: Po or pore-plate, and x or groove-plate, located somewhat more ventrally (fig. 23). The dorsal edge of P o is convex while the ventral is concave; both lateral edges diverge towards the back. This small plate of approximately 3-4pm is perforated in the center by a pore ca. 1.5 pm in diameter. In the light microscope this structure appears as a regular pore, but SEM photographs reveal that it is occluded by a plug, probably protoplasmatic in nature (fig. 16). Plate x is subrectangular and joins Po and 1 '. The pore-platelets are surrounded by ridges which arise from adjacent plates (fig. 16, 17). The structure of the apical pore area is similar to that of Peridinium bipes (Boltovskoy 1976), and also to that of many species of the genus Protoperidinium (Balech 1974; Dodge & Hermes 198 1). Plate 2: SEM micrographs of thecae of Peridinium gutwinskii. Scale bars 20pm. - Fig. 8: Ventral view showing the lobe of plate 7 ' ' and the antapical spine. Fig. 9: Right lateral view. Fig. 10: Apical view. Higher marginal ridges can be seen at the overlapping margins of the plates. Fig. 1 I : Latero-antapical view. Fig. 12: Dorsal view. Fig. 13: Antapical view showing slightly different size but similar outshape of the antapical plates. Cingular tabulation: There are five cingular plates, their position corresponding to the five postcingular ones. The four intercingular sutures correspond to the sutures between the adcingular plates in the epitheca and hypotheca. The height of the cingulum is homogeneous along its trajectory but it is much more shallower at the ending (plate 5c) suggesting that its last section is the less functional as a protective groove for the transversal flagellum. Sulcal tabulation: The sulcus is formed by five plates; their mutual relationships, as well those with neighboring plates (fig. 7), are similar to those found in other mem- bers of Peridinium (Evitt & Wall 1968, Boltovskoy 1973, 1975, 1976). Observation of the sulcal plates without dissociating them is impossible. The anterior sulcal plate (sa) is almost completely covered by the posterointernal lobe of plate 7 ' '. In the light microscope the sa plate and the right sulcal plate (sd), can be distinguished due to transparence as a sinuous refractive area along the edge of the above mentioned lobe (figs. 1, 6), extending towards the hypotheca and beyond the antero-internal corner of 5 ' ' '. Plates sa + sd contact plates 7 ' ' + 5c at a very small angle, in such a way that in ventral view of the theca, the internal face of sa is directed towards the viewer. This can be seen isolating these sulcal plates and positioning them in the same angle in which they were originally located (figs. 32, 33). The plane defined by the left sulcal plate (ss) is nearly perpendicular to 1 ' ' ' and the posterior sulcal plate (sp) is bent so that its left and right margins are implanted perpendicularly to 1 ' ' ' and 5 ' ' ', respectively. Plate sa has a very peculiar aspect: it presents a main trapezoidal body joined to 7 ' ', and a limb above the upper half of its left side. This limb is folded over the main body on the same plane as the beginning of lc , with which it merges (Figs. 7,25,26, 34). Plate sd is larger in height than in width; it presents a concavity on its right edge which corresponds to the insertion of plate 5c, and a longitudinal list along its in- ternal edge extending beyong its posterior end (figs. 27, 35). Plate ss is elongated longitudinally and sickle-shaped (figs. 29, 37), while the posterior accessory sulcal plate (spa) is through-shaped with a rounded posterior end (figs. 28, 36, 37). Plate sp has two short limbs directed forwards, separated by an arcuate notch where spa is implanted. The left limb is thinner than the right one, and is furnished with a tri- angular spur which can give the false impression of being a spine of 1 ' ' '. The pos- terior end of sp is tapering (figs. 30, 31). The right internal sulcal platelet was not observed. Emergence of the flagella: The morphology of the sulcal complex suggest that the flagella emerge from an elongated opening formed by the internal edges of the plates sa, ss, sd, and spa, which surround the flagellar pore. The first part of the trajectory of the transversal flagellum is inside the narrow channel formed by the fold of sa; while the first part of the trajectory of the longitudinal flagellum proceeds within an almost tubular structure formed by spa, ss, and the list of sd, finally emerging at the junction of sp and spa. All sulcal plates with the exception of spa have pores. Their areas most closely in contact with the flagella are the least ornamented, while sp presents a reliefed meshwork similar to that on the main plates. Plate 3: SEM micrographs of thecae of Peridinium gutwinskii. - Figs. 14-15: Specimens with broad intercalary bands. Scale bars IOpm. Fig. 14: Ventral view. The external suture close to the underlapping left margin of plate 1 ' ' ' can be seen. Fig. 15: Apical view showing inequal growth of intercalary bands between the precingular plates, and elongated apical pore area. Figs. 16-17: Apical pore areas bordered by ridges of the surrounding plates. Scale bars 1 pm. Fig. 16: Detail of a specimen without intercalary bands. Apical pore occluded by a plug can be seen. Fig. 17: Detail of a theca with well developed inter- calary bands. Apical pore area elongated due to the broad intercalary band between the plates x and 1 '. Fig. 18: Detail of the ventral region showing the ornamentation and the lobe of plate 7 ' '. Scale bar 5 pm. Figs. 19-20: Detail of antapical spines. Scale bars 2pm. Fig. 19: Ventral view. Fig. 20: Left lateral view. The spine appears like a spur with two triangular tips. Growth bands and overlapping system: The degree of development of the inter- calary bands or growth bands varied greatly in the specimens studied, reaching up to 15 pm in width (fig. 15). The differential growth of the intercalary bands demon- strated by Boltovskoy (1979) for some Peridinium is also present in this species: the sutures between the adcingular plates which are in line with intercingular sutures have a much more growth than those which are not aligned. Thus, on the epitheca the intercalary bands with highest development are: 1 ' '-2 ' ', 3 ' '-4 ' ', 4 ' '-5 ' ' and 6 ' '-7 ' ' (figs. 15,21). These are aligned with the intercingular intercalary bands (fig. 23, below), as well as with the four intercalary bands between the postcingular plates (figs. 13,22). The longitudinal intercalary bands taper towards the apex. In the area of the apical pore growth is scarce or absent altogether, except for the suture x-1 ' (figs. 15, 17, 23); thus, large specimens have a more elongated poral area due to this wider inter- calary band (figs. 15, 17). Among sulcal plates only the posterior end of sp shows considerable growth, which can be seen from the great development of the articular flanges (fig. 31). The posterior edge of the plate sa can also have an articular flange, but the latter is always very narrow (fig. 25). Although the plate overlapping pattern has not been studied in detail, it seems to be similar to that of some species of Protoperidinium (Balech 1974; Gocht & Netzel 1974) and of Peridinium cinctum (O.F. Miiller) Ehrenberg (Diirr 1979). Two ex- ternal features can be used as evidence of the overlapping pattern in Peridinium gutwinskii: (a) The sutural ridges are usually higher at the overlapping margins of the plates (fig. lo), and (b) in specimens with well developed intercalary bands the sutures in the outer surface of the theca are closer to the underlapping margins of the plates (fig. 14,23). Discussion Some differences between the materials of Peridinium gutwinskii studied by me with respect to those described by other authors should may justify establishing a new variety or even a new species. But there are neither homogeneity between the illus- trations given by previous authors (see table I). I prefer to follow the idea that the essential thing is not to name deviations, but to describe variation, until we have more information on materials from more localities. Thus the morphological and distributional variations of P. gutwinskii are discussed and compared with that of closely related species based on the present results and previous papers. 1. The basic tabulation as well as the cingular and sulcal ones, the mode of inter- calary bands development and the ornamentation of P. gutwinskii confirm the inclu- sion of this species in Peridinium sensu strict0 (sensu Boltovskoy 1979 and Boltovs- koy in: Bujak & Davies 1983, p. 47). The features of the sulcal complex of Peri- dinium s.s. constitute a new evidence of the homogeneity of this genus but, at least so far do not allow establishing clear intrageneric relationships, despite the fact that each species has a distinctive sulcal structure. The number and position of the cingular plates of specimens from Corrientes are the same as those illustrated by Plate 4: LM micrographs of parts of thecae of Peridinium gurwinskii taken in temporary water mounts. (Figs. 21-31: Stained with iodinated iodhydric acid. Figs. 32-37: Nomarski's interference contrast illumi- nation.). - Figs. 21-24: Thecal plates flattened under a coverslip. Fig. 21: Epitheca. Fig. 22: Hypotheca with somewhat atypical outshape of the plates 3 ' ' ' and I ' ' ' '. Fig. 23: Detail of the ventro-apical area of a specimen with broad intercalary bands (viewed from a dorsal direction) showing apical pore platelets with a non occluded pore, rhombic plate 1 ', plate 4 ', lobed plate 7 ' where porosity can be seen and plate 5c. In the intercalary bands external sutures (in focus) are close to the underlapping margins of the plates. Fig. 24: Plate 2" ' ' bearing the antapical spine. Figs. 25-37: Isolated sulcal plates. Fig. 25: Flattened anterior sulcal plate. Fig. 26: Folded anterior sulcal plate. Fig. 27: Right sulcal plate. Fig. 28: Posterior accessory sulcal plate. Fig. 29: Left sulcal plate. Fig. 30: Posterior sulcal plate. Fig. 31: Posterior sulcal plate showing broad articular flanges on its posterior border. Figs. 32-33: Views at different focuses of the anterior sulcal plate and the right sulcal plate oriented as in the theca in ventral view. The folded part of the anterior sulcal plate. Fig. 35: Right sulcal plate. Fig. 36: Posterior accessory sulcal plate. Fig. 37: Left sulcal plate united to posterior accessory sulcal plate, slightly flattened under a coverslip. Woloszynska (1923, figures 5 and 6) while the sulcal ones can not be compared with any material since they are described here for the first time. Among the sulcal plates of P. gutwinskii, the sulcal anterior plate is the most distinctive, while the left sulcal plate is very similar to that of P. gatunense Nygaard, the right sulcal plate to that of Table I: Distribution and morphological variability of Peridinium gutwinskii. Latitude (approx. Distribution P. cinctum, and the posterior sulcal plate, although higher, to those of P. cinctum and P. bipes. The posterior accessory sulcal plate is alike in all the above taxa. 2. Probably the most outstanding feature of P. gutwinskii is the lobe of the plate 7 ' ' which covers the anterior part of the sulcus and therefore is responsible of the folding of the anterior sulcal plate and the peculiar position of both, the ante- rior sulcal and the right sulcal plates. The lobe of 7 ' ' is shared only by the speci- mens from Borneo figured by Lindemann (1931, figures 34-37). Unfortunately these figures are not widespread since they were not reproduced in the monographs by Lef2vre (1932), Schiller (1937) and Huber-Pestalozzi (1968). The variability on the outshape of the plates in different populations of the same species of Peridinium s.s. is relatively common and was demonstrated, for example, in P. gatunense (Boltovs- koy 1983; Hickel & Pollingher 1988). 3. Another relevant feature of P. gutwinskii from Corrientes is the penta plate ar- rangement of the dorsal epitheca, being the quadra pattern typical of this species. Only Lef2vre (1932) found specimens with a penta pattern previously (P. gutwinskii tab. 6 travectum Lef2vre 1932) in Tananarive, Madagascar, the same area from where quadra specimens were collected. The character penta is common in Peri- dinium s.s. (P. cinctum, P. gatunense), as well as in Protoperidinium and it is almost always associated with the second intercalary plate displaced to the left of the plane of symmetry. On the contrary, in P. gutwinskii the pentagonal second inter- calary plate is displaced towards the right. It is interesting to note that there are some cases where the quadrangular 2a plate is strongly displaced to the right too, but without contacting the plate 5' ', as it does in the penta specimens (see Woloszynska 1912, figure 22D, E; CoutC & Iltis 1984, figure 25). The right-penta arrangement is very rare in Peridinium (as well as in Protoperidinium) and it occurs also in P. bipes (P. bipes tab. y travectum Lefevre 1932). Woloszynska 1912, 1923, 1930 ::ittra Plate 7" Plate 2a Antapical plates Posterior spine Measures L. in pm Trd. Lindemann 1931 Borneo ( * ) Features which differ from those of Woloszynska's rnateri-11s. regular quadra similar absent 40-60 35-60 Lefevre 1932 Madagascar lobed* quadra similar absent --- --- cout6 & Iltis 1984 Ivory Coast regular unequal* absent 40 - 60 35-60 Present study Corrientes regular quadra similar absent 40-55 40-48 lobed* penta* similar present* 65-85* 53-76 On the other hand, there are at least two more examples where the pattern of the dorsal epitheca can vary within a single species: the above mentioned case of P. bipes which is normally hexa, and the penta species P. gatunense which can be quadra (P. gatunense tab. y travectum Lefevre 1932). Another case, from Protope- ridinium, is Pr. claudicans (Paulsen) Balech which can be both penta or quadra (Balech 1974). Obviously it should be interesting to note if the conspecific specimens with different dorsal tabulations live together at the same time and at the same place or constitute independent populations. The latter is the case of my material and apparently of the three examples of tabular inconsistency used from Lef6vre. 4. As observed on the sketches given by the different authors, the hypothecal mor- phology of P. gutwinskii is extremely variable depending on the concavities and convexities of the antapical plates. Only the specimens of Lefevre (1932) have a strong annular constriction on the hypotheca and quite different size and shape of the antapical plates due to an oblique suture between them. On the rest of the mate- rials the antapical plates are of more or less similar outshape, being the first ant- apical plate slightly larger then the second. The same kind of intraspecific variability of the outshape of the antapical plates is not rare in other species of Peridinium s.s. 5. The specimens of P. gutwinskii from Asia and Africa lack the posterior spine, which is present on the thecae studied by me. This structure is homologous with the antapical lists of some species of Peridinium s.s. In P. bipes, likewise in P. gutwins- kii, the lists can have different degree of development or be absent (Lef6vre 1932; Boltovskoy 1976). 6. The measures of P. gutwinskii from Corrientes are much more larger than the ones given in the literature, though Lindemann (1931), whose materials are the closest to those described here (cell shape, lobed 7" plate), does not give any measure and Lef6vre (1932) repeats the Woloszynska's ones (see table I). Thus, the total variability of the species is 40-85 pm in length and 35-76pm in transdiameter. Such variation rank is not rare in Peridinium s.s. and it is known for P. willei, P. bipes and P. palustre (Lindemann) Lefevre, which have 48-83 pm. 40-81 pm and 50- 90 pm in length, respectively, being 37-73 pm, 37-60 pm and 50-90 pm their trans- diameter (Kiselev 1950 and my own data). 7. P. gutwinskii was considered as a tropical species restricted to Asia and Africa. Its occurrence in Argentina constitutes its southernmost record which enlarges its distribution to a subtropical waterbody. There are nine degrees of latitude between its previous southernmost record (Tananarive, Madagascar) and the present one (Garabi, Corrientes). It is not too much if it is considered that the next northern locality of this species (Java) is about 10" from Tananarive, and the distribution of another tropical freshwater dinoflagellate, P. gatunense, is between Maryland, U.S.A., at 38"N and San Luis, Argentina, at 34"s (Thompson 1947, and my own data). References BALECH, E. (1974): El gCnero Protoperidinium Bergh, 1881 (Peridinium Ehrenberg, 1831, partim). - Rev. Mus. Arg. Cienc. Nat. "B. Rivadavia", Hidrob. 4: 1-79. BOLTOVSKOY, A. (1973): Peridinium gatunense Nygaard. Estructura y estereoultraestructura tecal (Dinoflagellida). - Physis B (Buenos Aires) 32: 331-344. BOLTOVSKOY, A. (1975): Estructura y estereoultraestructura tecal de dinoflagelados. 11. Peridinium cinctum (Miiller) Ehrenberg. - Physis B (Buenos Aires) 34: 73-84. BOLTOVSKOY, A. (1976): Estructura y estereoultraestructura tecal de dinoflagelados. 111. Peridinium , bipes Stein, forma apoda n.f. - Physis B (Buenos Aires) 35: 147-155. BOLTOVSKOY, A. (1979): Estudio comparative de las bandas intercalares y zonas pandasuturales en 10s generos de dinoflagelados Peridinium s.s.. Protoperidinium y Palaeoperidinium. - Limnobios 1: 325-332. BOLTOVSKOY, A. (1983): Peridinium cinctum f. westii del Mar de Galilea, sinbnimo de Peridiniurn gatunense (Dinophyceae). - Limnobios 2: 413-418. BUJAK, J.P. & E.H. DAVIES (1983): Modern and fossil Peridiniineae. - Amer. Assoc. Stratigr. Palynol., Contrib. Ser. 13: 1-216. COUTE, A. & A. ILTIS (1984): Mise au point sur la flore peridiniale (Algae, Pyrrophyta) d'eau douce du Cote d'lvoir. -Rev. Hydrobiol. trop. 17: 53-63. DODGE, J.D. & H.B. HERMES (1981): A scanning electron microscopical study of the apical pores of marine dinoflagellates (Dinophyceae). - Phycologia 20: 424-430. DURR, G. (1979): Elektronenmikroskopische Untersuchungen am Panzer von Dinoflagellaten. 11. Peridinium cincturn. - Arch. Protistenk. 122: 80-120. EVITT, W.R. & D. WALL (1968): Dinoflagellate studies. IV. Theca and cyst of recent fresh-water Peridinium limbatum (Stokes) Lemmermann. -Stanford Univ. Publs., Geol. Sci. 12: 1-15. GOCHT, H. & H. NETZEL (1974): Rasterelektronenmikroskopische Untersuchungen am Panzer von Peridiniurn (Dinoflagelata). - Arch. Protistenk. 116: 381 -410. HICKEL, B. & U. POLLINGHER (1988): Identification of the bloom forming Peridinium from lake Kinneret (Israel) as Peridinium gatunense (Dinophyceae). - Br. phycol. J. 23: 115-1 19. HUBER-PESTALOZZI, G. (1968): Das Phytoplankton des Siisswassers. Cryptophyceae, Chloromona- dophyceae, Dinophyceae. - In: Die Binnengewssser, A. Thienemann (ed.), vol. 16, pt. 3 (2nd edition). Schweizerbart'sche Verlagsbuchhandlung, Stuttgart. Pp. 1-322. KISELEV, I.A. (1950): Pantzyrnye zhgutikonostsy (Dinoflagellata) morey i presnykh vod SSSR. - In: Opredelitel po faune SSSR 33. Akad. Nauk SSSR, Moskow-Leningrad. Pp. 1-279. KOFOID, C.A. (1909): On Peridinium steini Jorgensen, with a note on the nomenclature of the skeleton of the Peridinidae. -Arch. Protistenk. 16: 25-47. LEFEVRE, M. (1932): Monographie des espkces d'eau douce du genre Peridinium. - Archs. Bot. 2: 1-210. LINDEMANN, E. (1931): Die Peridineen der Deutschen Limnologischen Sunda-Expedition nach Sumatra, Javaund Bali. -Arch. Hydrobiol. 8: 691-732. RUTTNER, F. (1952): Planktonstudien der Deutschen Limnologischen Sunda-Expedition. - Arch. Hydrobiol. 21: 1-247. SCHILLER, J. (1937): Dinoflagellatae (Peridineae) 2. - In: L. Rabenhorst's Kryptogamen-Flora von Deutschland, tisterreich und der Schweiz, vol. 10, pt. 3. Akad. Verlags., Leipzig. Pp. 1-590. THOMPSON, R.H. (1947): Fresh-water dinoflagellates from Maryland. - Chesapeake Biol. Labor. Publ. 67: 1-28. VUCETICH, M.C. (1978): Nuevos aportes a1 conocimiento de 10s tecamebianos del Dominio Sub- tropical. - Neotropica 24: 79-90. WOLOSZYNSKA, J. (1912): Das Phytoplankton einiger javanischer Seen, mit Beriicksichtigung des Sawa-Planktons. -Bull. Akad. Sc. Cracovie, Classed. Sc. Math. et Nat., Ser. B: 649-709. WOLOSZYNSKA, J. (1923): Javanische Siisswasserperidineen. - Acta Soc. Bot. Pol. 1: 263-266. WOLOSZYNSKA, J. (1930): Kenntnis des Phytoplanktons tropischer Seen. - Archs. Hydrob. Rybactwa 5: 159-169. 380 gut369.tif gut370.tif gut371.tif gut372.tif gut373.tif gut374.tif gut375.tif gut376.tif gut377.tif gut378.tif gut379.tif gut380.tif