Fifth NAWQA Taxonomy Workshop on Harmonization of Algal Taxonomy June 2001

Transcription

1 Fifth NAWQA Taxonomy Workshop on Harmonization of Algal Taxonomy June 2001 Report No The Patrick Center for Environmental Research held June 2001 at The Academy of Natural Sciences 1900 Benjamin Franklin Parkway Philadelphia, PA Prepared by Eduardo A. Morales 21 June 2002

2 INTRODUCTION The Fifth NAWQA Diatom Taxonomy Workshop was held at the Academy of Natural Sciences of Philadelphia on June Specialists participating in the workshop were: Kalina Manoylov from Michigan State University; Dr. Rex L. Lowe from Bowling Green State University; William R. Cody, environmental consultant based in Ohio; Dr. Loren L. Balhs, environmental consultant based in Helena, Montana; Todd A. Clason, environmental consultant based in Seattle, Washington. Dr. Marina Potapova, Dr. Eduardo A. Morales, Dr. Donald F. Charles, Diane M. Winter, Karin C. Ponader, and Frank W. Acker from the Patrick Center for Environmental Research s Phycology Section at the Academy of Natural Sciences of Philadelphia, also participated in the workshop and helped to organize it. The first, second, and third NAWQA taxonomy workshops had the overall objectives of harmonizing taxa names used in the ANSP and University of Louisville/University of Michigan laboratories, identifying reference images for each taxon, and agreeing on up-to-date nomenclature to use when analyzing NAWQA 1994 and 1997-start samples (See Clason and Charles, 1999; 2000; and Morales and Potapova, 2000). The fourth NAWQA Diatom Taxonomy Workshop focused on issues concerning the taxonomy of some problematic Navicula and Gomphonema species. Taxa that received most attention during that workshop occur commonly in NAWQA material and are often difficult to identify during routine light microscopy (Morales, 2001). This fifth workshop concentrates on additional taxa of the genus Navicula. These problematic taxa were arranged in complexes, which comprise taxa morphologically similar to each other and very difficult to distinguish during routine analyses of NAWQA samples. The complexes were the following: Complex 1 (Presented by L. Bahls) Navicula caterva N. phyllepta N. reichardtiana Complex 2 (Presented by W. Cody) Navicula incerta N. odiosa N. salinicola Complex 3 (Presented by K. Manoylov) Navicula kotschyi N. texana N. savannahiana Complex 4 (Presented by M. Potapova/D. Winter) Navicula lateropunctata THE ACADEMY OF NATURAL SCIENCES 1 PATRICK CENTER FOR ENVIRONMENTAL RESEARCH

3 N. aikenensis N. sanctaecrucis Complex 5 (Presented by R. Lowe) Navicula schroeteri N. schroeteri var. symmetrica N. schroeteri var. escambia Complex 6 (Presented by K. Ponader) Navicula germainii N. viridula N. viridula var. linearis N. viridula var. rostellata An electronic version of the above list was sent to workshop participants. They were asked to choose a complex and prepare a presentation including the historical background of the taxa, different views in the literature as to their taxonomic position, affinities with closely related entities, features used for identification, and relevant ecological information that might be helpful in the characterization of the taxa. Each presentation was to last 15 minutes and be followed by brief discussions. During the workshop, laboratory sessions were held following sets of presentations. They concentrated on examination of type slides from the ANSP Diatom Herbarium and/or permanent slides from NAWQA study units. During these sessions, intensive discussion and literature search led in many cases to the application of correct names to problematic taxa, or to the conclusion that more research was needed in order to be confident about the identity of certain species and their varieties. During observation of type slides and laboratory discussions, Dr. Charles W. Reimer s participation was often crucial in reaching a decision regarding the application of a name. He also provided references and material for some of the taxa covered during the workshop. K. Manoylov and D. Winter presented images and documentation of unknown taxa that they had encountered during analyses of NAWQA material. Also, K. Ponader presented an unknown taxon from the Piedmont physiographic region of New Jersey. Workshop participants discussed these images and documentation. Permanent slides in which the mentioned taxa had been found were analyzed in some instances. The present report includes the outcomes of discussions arranged by taxonomic complex and supporting plates. Plates with unknown taxa are also presented. These plates should be used by NAWQA taxonomists as a reference for future identification of depicted taxa. Plates include images taken during and after the workshop and taken by participants as well as images scanned from bibliographical references. Morphological terminology used in this report follows Barber and Haworth (1981) and Cox (1996). THE ACADEMY OF NATURAL SCIENCES 2 PATRICK CENTER FOR ENVIRONMENTAL RESEARCH

4 E. Morales prepared a document containing taxonomic rules to guide the way in which new and unknown taxa are reported in NAWQA counts and to facilitate the documentation process. He sent a draft of this document to workshop participants before the workshop. The document was discussed during the workshop and corrections and additions were made. A final version of this document is presented as Appendix 1. It should be used by all analysts during analyses of NAWQA material. Workshop participants also reviewed the 1997-start diatom list and made corrections to misspellings and transcription errors that occurred during the preparation of the Third Workshop Report (Morales and Potapova, 2000). These corrections were based on careful reexamination of literature and on discussions on each one of the issues. The revised version of this list is presented as Appendix 2. This list should be strictly followed for analysis of 1997-start samples and any changes avoided at all costs. Additions of new taxa can be made only through E. Morales at ANSP. THE ACADEMY OF NATURAL SCIENCES 3 PATRICK CENTER FOR ENVIRONMENTAL RESEARCH

5 WORKSHOP OUTCOMES Navicula caterva N. phyllepta N. reichardtiana L. Bahls included N. cryptocephala var. veneta in his presentation of this complex arguing that it can produce morphs that resemble representatives of the other three taxa included in this complex. He made the additional argument that the name N. cryptocephala var. veneta may have been applied to different taxa in the past, but that now, in the light of recent publications by Lange-Bertalot and collaborators, new, alternative names are available in the literature. Krammer and Lange-Bertalot (1986) considered that the var. veneta of N. cryptocephala is a sufficiently distinct taxon, and thus, it should be recognized as a separate entity. The same authors then decided to re-adopt the basyonym Navicula veneta Kützing and reject the combination proposed by Rabenhorst (1864). Workshop participants agreed with Krammer and Lange-Bertalot s decision and will use the name N. veneta. This latter name had been adopted during the fourth workshop report, but without formal analyses of NAWQA material (Morales, 2001). Future identification of this taxon in NAWQA material should be based on Plate 32, Figs. 1-4 in Krammer and Lange-Bertalot (1986). Briefly, N. veneta can be recognized by its characteristic concave outline at both polar ends, which give the poles a delicate rostrate configuration. Also, the central area exhibits a somewhat rectangular subfascia flanked by a sequence of short-long-short striae on both sides. Striae arrangement varies from slightly radiate at the central area to convergent at the poles. The raphe is filiform and only two delicate dark spots, corresponding to the central terminals, can be seen under light microscopy (LM) when the central area is brought into focus. Examination of type material for N. caterva led to the conclusion that this is a distinct taxon. Its identification in NAWQA material should be based on Krammer and Lange-Bertalot (1991, Plate 68, Figs ) and Plate 1, Figures 1-8 presented herein. The valve ends are subcapitate and more elongated in N. veneta. Striation is also much finer and different at the central area than that of N. veneta. The subfacia in the latter is very difficult to distinguish because the striae are the same length throughout the length of the valve and on both sides of the raphe. There is, however, at least one conspicuously short striae on one or both sides of the central area. The striae sequence short-long-short on one side of the central area is less frequent. The arrangement of the striae varies from slightly radiate at the central area to parallel or slightly convergent at the poles. The raphe is filiform. When the central area is brought into focus, the central terminals and part of the slit running along the apical axis of the valve can be seen. Navicula phyllepta, as presented by Krammer and Lange-Bertalot (1986, Plate 32, Figs. 5-11), probably represents a mixture of different taxa. Representatives of this taxon in NAWQA material resemble those depicted in Figures 5, 6, and 11, which probably correspond to the most THE ACADEMY OF NATURAL SCIENCES 4 PATRICK CENTER FOR ENVIRONMENTAL RESEARCH

6 typical morphs of this species. The ends of the valve vary from slightly rostrate to apiculate and produced. The subfascia in the central area is slightly rounded and flanked by more or less equally shortened striae on both sides. The striae vary from slightly radial at the center to parallel toward the ends. The raphe is filiform and only a portion of it at the central area, up to half way toward the ends, can be seen when the central area is in focus. The terminations of the raphe at the central nodule are not enlarged or are only slightly expanded; hence, the raphe appears as a dark line interrupted at the central nodule. Navicula reichardtiana is very similar to N. caterva (Plate 1, Figs. 9-11). Its valves are, however, more heavily silicified with a more conspicuous raphe and wider striae. The ends of the valve are rostrate. The terminations of the raphe at the central area can be seen as two conspicuous round dots. When the central area is in focus the slit of the raphe can be seen up to half way toward the end of the valves. The subfascia is more or less linear at the central area and clearer than in N. caterva. The central area has a very short stria on one or both sides, a long stria flanked by two shorter ones on both sides, or a short stria on one side and a long one flanked by two shorter ones on the other. The striae arrangement varies from strongly radiate and slightly sigmoid at the central area to parallel and straight toward the ends. N. reichardtiana may have been confused with N. cryptocephala var. veneta sensu Patrick and Reimer (1966). The diagram presented by these authors (Plate 48, Fig. 5) is congruent with N. reichardtiana. Analysis of the reference slide used by Patrick and Reimer (A- Cl. & Moll. No. 255) led workshop participants to believe that the drawing presented by these authors is not accurate, because the specimen in A-Cl. & Moll No. 255 actually corresponds to N. veneta sensu Krammer and Lange-Bertalot (1986). Future identification of N. reichardtiana should be based on Plate 1, Figs and Krammer and Lange-Bertalot (1991, Plate 68, Figs ). This taxon also appears in Krammer and Lange-Bertalot (1986, Plate 33, Figs ) as N. species 2. Navicula incerta N. odiosa N. salinicola The name Navicula incerta appears twice in the literature: Ehrenberg (1837) and Van Heurck ( , determined by Grunow). N. incerta sensu Grunow is the taxon that appears in NAWQA slides (Plate 1, Figs. 16 and 17). Since this name was already occupied by the taxon erected by Ehrenberg, Lange-Bertalot (in Krammer and Lange-Bertalot, 1986) decided to rename the taxon in Van Heurck ( ) as Navicula incertata. Navicula incertata is a small taxon with elliptical valves. The striae are parallel throughout the length of the valve or slightly radial at the center and slightly convergent toward the valve ends in larger specimens. The subfascia in the central area is somewhat rectangular and very reduced. Only two striae on each side of the central area are slightly shorter. The THE ACADEMY OF NATURAL SCIENCES 5 PATRICK CENTER FOR ENVIRONMENTAL RESEARCH

7 raphe is very delicate and only two dark dots corresponding to the central terminals can be observed when the central area is brought into focus. Navicula odiosa is also a small taxon with elliptical valves. The ends of the valves are, however, more acute than in N. incertata. The central area is very reduced. The striae vary from radiate at the central area to parallel toward the ends. One or more shorter striae can be seen on both sides of the central. The raphe is filiform and only a portion of it (including two small dark dots at the central nodule) can be seen when the central area is in focus. Navicula salinicola sensu Krammer and Lange-Bertalot (1986, Plate 35, Fig. 9-10) probably represents a mixture of two taxa. Figure 9 presented by these authors corresponds to the type specimen presented by Hustedt (Hustedt Collection 267/22). On the other hand, Figure 10 is congruent with the concept of N. incertata (compare this figure with Figs in the same plate). Simonsen (1987), in his publication on Hustedt s diatom types, explains that the name N. salinicola does not appear in any of Hustedt s records and that a type specimen had not been designated. Simonsen then designates a lectotype based on material that Hustedt had mentioned in his original protologue (Hustedt Collection slide N7/80) and that contained a fairly common population of organisms resembling Hustedt s original drawings (Hustedt, 1939). When this lectotype of N. salinicola and the drawing in the original protologue by Hustedt are compared to the original diagram presented by Grunow (in Van Heurck, , Plate 14, Fig. 43) for N. incerta, no differences can be seen. It appears, therefore, that these two taxa are synonyms. If this is the case, N. incerta has priority following the ICBN. As explained above, N. incerta has been renamed by Krammer and Lange-Bertalot (1986) as N. incertata (and they chose slide N7/80 in Hustedt s collection as the neotype slide for this taxon) because the name N. incerta was already occupied by a taxon described by Ehrenberg. NAWQA analysts should use the name N. incertata for specimens resembling those depicted in Plate 1 (Figs. 16 and 17) and in Krammer and Lange-Bertalot (1986, Plate 35, Fig ). Use of the name N. salinicola should be avoided and all NAWQA counts in which the name N. salinicola has been used should be changed to N. incertata. In his presentation of this taxon, W. Cody included the small naviculoids: N. aliena, N. carniolensis, N. cincta fo. minuta, and N. tenelloides, which can be identified using Krammer and Lange-Bertalot (1986) and Lange-Bertalot et al. (1996b). THE ACADEMY OF NATURAL SCIENCES 6 PATRICK CENTER FOR ENVIRONMENTAL RESEARCH

8 Navicula kotschyi N. savannahiana N. texana Navicula kotschyi has been reported from many NAWQA study units and it is relatively easy to recognize. Future identification of this taxon in NAWQA material should be based on pictures presented here (Plate 1, Figs ) and by Krammer and Lange-Bertalot (1986, Plate 60, Figs ). Although N. kotschyi seems to be related to taxa that have been recently transferred to the genus Luticola, it is different in a number of features. The raphe is filiform and straight in contrast to the raphe of Luticola, which is bent at the central nodule. Additionally, N. kotschyi lacks a stigma in the central area, which is present in all species of Luticola. The valve ends and the arrangement of the striae in the central area seem to be very variable features in N. kotschyi. This has led to the description of morphological variants as different species. Workshop participants believe that N. savannahiana and N. texana are simply morphs that can easily be included in the range of variation exhibited by N. kotschyi. Support for this conclusion was found in the observation of the variability in the type specimens and populations for N. savannahiana (Plate 1, Figs ) and N. texana (Plate 1, Figs ). Moreover, whenever a large of population of N. kotschyi is found in NAWQA samples, morphs resembling N. savannahiana and N. texana intergrade with the more typical morphs of N. kotschyi. An additional feature that seems not to be mentioned in the protologue of N. kotschyi is the presence of a pseudoseptum at both ends of the valve (Plate 1, Figs. 27, 30, and 32). This structure is more conspicuous when the valves lie on their sides (girdle view). K. Manoylov, in her presentation of this complex, showed pictures of a taxon from the Iroquois River (Upper Illinois River Study Unit) that seems to be closely related to N. kotschyi, but presents larger valves, coarser striation, and mostly rostrate apical ends (Plate 2). Until the relationship of this latter taxon and N. kotschyi is clarified, it should be kept separate as N. aff. kotschyi (NADED # 93161). Navicula aikenensis N. lateropunctata N. sanctaecrucis In their presentation of this complex, D. Winter and M. Potapova included N. tugelae as a taxon sharing some features with the other species in this complex. The valves of N. tugelae are lanceolate with rostrate ends. The central area subfascia is somewhat circular and lacks a punctum (stigma). The striae vary from parallel to slightly radiate in the central area to radiate at THE ACADEMY OF NATURAL SCIENCES 7 PATRICK CENTER FOR ENVIRONMENTAL RESEARCH

9 both ends of the valve. The raphe is filiform and can be seen in its entirety when the central area is in focus (Plate 3, Figs. 8 and 9). Specimens in NAWQA material identified as N. tugelae differ from the African type material presented by Cholnoky (Cholnoky, 1956, Plate 4, Fig. 99, pg. 82) (Plate 3, Fig. 10). The latter is broader at the central portion of the valve, which gives the impression that the valve ends are more acute. Although this may be simply an error of interpretation of the true shape of the taxon in Cholnoky s drawing (the American specimens can actually get 1 micrometer wider than the range given by Cholnoky), the striae in the African type are definitely denser. Another taxon that resembles N. tugelae (both the African and American versions) is N. kriegeri. In the latter, however, the valves are elliptical in shape with broad ends, but this seems to be the only observable difference. Although the striae appear to be sparser in Krasske s original drawing (Lange-Bertalot et al., 1996a, pg. 124) and in photographed specimens from the type material (Lange-Bertalot et al., 1996b, Plate 14, Figs , pg. 232), they match exactly the range found in NAWQA specimens. More detailed studies are necessary in order to clarify the true identity of the three taxa mentioned above. For the time being, specimens found in NAWQA samples will be identified as N. aff. kriegeri NAWQA MP Krasske (NADED # 93167) (Plate 3, Figs. 8 and 9). N. aikenesis has a lanceolate shape, but is not as broad as N. tugelae (Plate 3, Figs. 1-7). The valve ends are also rostrate, but somewhat more elongated than in N. tugelae. The subfascia is rectangular and it is flanked by two shorter isolated striae on both sides. An isolated punctum is present in the central area, at the end of one of the shortened striae. The striae are radial throughout the entire valve, becoming curved at the polar ends. The raphe is filiform and most of it can be seen when the central area is brought in focus, disappearing only toward the ends. In a recent publication (Rumrich et al. 2000, Plate 66, Figs. 1-15, pg. 373), Lange-Bertalot described Geissleria schmidiae as a new taxon from Ecuador. This taxon is probably conspecific with N. aikenesis and should be studied further. N. lateropunctata is broadly lanceolate and its ends are narrowly rostrate (Plate 3, Figs ). The central subfascia varies from circular to rhombic and presents one or more shortened striae on both ends. One to five punctae can be present in the central area. The striae are radiate throughout the valve, becoming slightly radiate at the polar ends. The raphe is filiform and at least three quarters of it can be seen when the central area is brought into focus under LM. N. sanctaecrucis has a broadly lanceolate shape with ends varying from narrowly rostrate and elongated to subcapitate (Plate 3, Figs ). The shape of the subfascia varies greatly following variations in the pattern of striation. This striation can vary from a situation in which all striae in the central area are equally shortened to the case in which only one or two striae are very short. The isolated punctum is lacking in the central area. The striae vary from parallel to slightly radiate in the central area to parallel at both ends. A pseudoseptum can be seen at both THE ACADEMY OF NATURAL SCIENCES 8 PATRICK CENTER FOR ENVIRONMENTAL RESEARCH

10 ends of the valves. The raphe is filiform and can be seen in its entirety when the central area is in focus. All the species in this complex with the exception of N. sanctaecrucis should be transferred to the genus Geissleria. N. sanctaecrucis seems to be related to the genus Parlibellus, but further studies are needed to demonstrate this relationship. N. schroeteri N. schroeteri var. escambia N. symmetrica N. schroeteri was originally described by Meister based on Asian material (Meister, 1932) (Plate 4, Fig. 1). It has heavily silicified valves, which are lanceolate in shape and with acute ends. The striae are also robust and composed of rectangular and/or square pores that can be clearly distinguished under the light microscope. The striae are radiate throughout the length of the valve. The raphe is filiform with its central terminals bent unilaterally. Specimens depicted in Krammer and Lange-Bertalot (1986, 1991) as N. schroeteri do not correspond to the type presented by Meister. Krammer and Lange-Bertalot s examples are less silicified and clearly elliptical in shape. Analyses of several slides from the ANSP Diatom Herbarium made by workshop participants revealed that specimens and populations identified as N. schroeteri are congruent with Krammer and Lange-Bertalot s photographs, and thus, they do not correspond with the type specimen presented by Meister either. N. schroeteri var. escambia was described by Patrick based on material from the Escambia River, Florida, USA (Plate 4, Figs. 2 and 4-6). This taxon has elliptical valves, radiate striae and a rectangular subfascia. The latter is displaced in the direction of the raphe terminals; hence, the striae on one side of the subfascia are shorter than the ones on the opposite side. The striae are composed of rectangular and/ or square pores, which are not as large as the ones in the nominate variety. The raphe is filiform with its central terminals bent unilaterally. The name N. schroeteri var. escambia should be applied to the photographs presented by Krammer and Lange-Bertalot (1986, Plate 38, Figs. 1-3; 1991, Plate 73, Figs.1-3) and to many specimens and populations in the ANSP Diatom Herbarium that have been identified as N. schroeteri. NAWQA slides do not contain N. schroeteri. This evidence and the fact that this taxon has not been reported in the literature produced from North American samples, probably suggests that this taxon is not found in North America. N. symmetrica is weakly silicified and also much narrower than the nominate and escambia varieties of N. schroeteri (Plate 4, Figs. 3 and 17-24). The valves are narrowly elliptical. The subfascia in the central area is less conspicuous that in the other two species in this complex and tends to be circular and positioned in the center of the valve. The striae surrounding the central area are more or less equally shortened on both sides. The striae vary from strongly radiate at the central portion of the valve to slightly radiate at the ends. The raphe THE ACADEMY OF NATURAL SCIENCES 9 PATRICK CENTER FOR ENVIRONMENTAL RESEARCH

11 is filiform and less visible than in the other two taxa mentioned above. The central raphe terminals are bent unilaterally. More profound studies are needed in order to determine whether N. symmetrica is simply a variety of N. schroeteri or a truly distinct species. Although N. symmetrica is easily distinguishable, its overall morphology is very similar to the nominate and escambia varieties of N. schroeteri. For now, the name N. symmetrica will continue to be used in NAWQA analyses. Navicula germainii N. viridula N. viridula var. linearis N. viridula var. rostellata N. viridula is the most robust of the four taxa included in this complex. Valves are lanceolate with rostrate ends (Krammer and Lange-Bertalot, 1986, Plate 37, Figs. 1 and 2). The central area presents an acute-angled subfascia with four or more shortened striae on each side. The striae are conspicuously lineolate and vary from strongly radiate at the central area to parallel and convergent at the ends. In some cases, the striae located half way between the central nodule and the ends of the valve can be slightly sigmoid. The raphe is filiform, with the central terminals bent unilaterally, and lies on a conspicuous channel which runs along the apical axis of the valve. N. viridula var. linearis is also heavily silicified (Krammer and Lange-Bertalot, 1986, Plate 37, Figs. 3 and 4). The shape of the valve tends to vary from linear (typical) to slightly lanceolate. The ends of the valves are more conspicuously rostrate than in the nominate variety. In some cases the ends can be subcapitate. The subfascia is somewhat circular and slightly displaced in the direction of the raphe terminals. Five or more shortened striae flank the central area, and are shorter on one side of the subfascia than on the other. The conspicuous lineolate striae are radiate at the central area, slightly sigmoid in the median portion of the valve, and convergent at the ends. The raphe is filiform and runs along a ridge. Its central terminals are bent unilaterally, but to a lesser degree than in the nominate variety. The two taxa above are probably the easiest to recognize in NAWQA samples and seem not to have been a problem for NAWQA analysts. In her presentation of this complex, K. Ponader showed photographs f a series of specimens from New Jersey, USA representing an intergradation of forms between N. viridula var. rostellata and N. germainii. This intergradation has also been observed by other analysts in NAWQA and ANSP Savannah River material. Workshop participants had access to the type material of N. germainii only. Analysis of this slide also revealed the existence of a series of intermediate morphs between N. germainii and N. viridula var. rostellata. THE ACADEMY OF NATURAL SCIENCES 10 PATRICK CENTER FOR ENVIRONMENTAL RESEARCH

12 Hoping to clarify this issue, workshop participants analyzed the reference slide used by Patrick and Reimer (1966) for the illustration of this taxon in their Diatoms of the United States volume (A-V.H. No. 87, on which the taxon was identified as N. rostellata Kützing by Grunow [in Van Heurck, ]). This slide has a large number of N. viridula var. rostellata and neither intermediate forms nor N. germainii could be found on the slide. In a recent publication (Rumrich et al., 2000) Lange-Bertalot and Rumrich created the name N. amphiceropsis to include forms such as the ones found in A-V.H. No. 87 (See Plate 5, Figs. 4-6 for similar specimens found in NAWQA material). The same authors commented that Grunow s concept of this taxon hence, Patrick and Reimer s concept of N. viridula var. rostellata are based on a taxon for which the type material has been lost. Lange-Bertalot and Rumrich then erected a neotype for this section of N. viridula var. rostellata calling it N. amphiceropsis, and make the remark that if the original Kützing type material is to be found, it is very probable that N. amphiceropsis will be prove to be a mere synonym of N. viridula var. rostellata. In the light of this nomenclatural and taxonomic confusion, NAWQA analysts will not use the name N. amphiceropsis. Also, since more information is needed to clarify whether N. germainii and N. viridula var. rostellata are separate entities, NAWQA analysts will continue to separate both taxa. Plates are presented herein, which analysts can use for future identification of these taxa (Plate 5). N. viridula var. rostellata has a lanceolate shape with subcapitate ends (Plate 5, Figs. 1-17). The subfascia varies from somewhat circular to acute-angled. The striae are radiate at the central area, slightly sigmoid in the median portion, and slightly convergent at the valve ends. The raphe is filiform, runs along a apical ridge, and it is bent unilaterally at the central area. N. germainii has a lanceolate shape with subrostrate ends (Plate 5, Figs ). The subfascia is very similar to that in N. viridula var. rostellata, but has shorter striae on both sides. The striae vary from radiate at the central area to slightly sigmoid in the median portion of the valve and convergent at the ends. The raphe is filiform and in general more delicate that in N. viridula var. rostellata. It also sits on a ridge and only the unilaterally bent central terminals can be clearly seen when the central area is in focus. Probably one of the most reliable features that can be used to separate N. viridula var. rostellata and N. germanii is the density of the striae. N. viridula var. rostellata has striae/10 µm, whereas N. germainii has striae/10 µm. Unknown Taxa K. Manoylov presented the following unknown taxa found in NAWQA material. Appropriate changes are required in ANSP databases: Navicula sp. 1 (NADED # 46444) (Oahu study unit, Plate 6, Figs. 3 and 4). This taxon should be identified as N. ruttneri var. capitata. THE ACADEMY OF NATURAL SCIENCES 11 PATRICK CENTER FOR ENVIRONMENTAL RESEARCH

13 Navicula sp. 1 (NADED # 93162) (Lower Tennesse River study unit, Plate 6, Fig. 6). No published name could be found for this organism. This taxon should be identified as Navicula sp. 25 NAWQA KM in future NAWQA counts. Navicula sp. 1 (NADED # 93163) (Plate 6, Fig. 5). Workshop participants could not find a published name for this organism. This taxon should be identified as Navicula sp. 26 NAWQA KM in the future. Navicula sp. 1 (NADED # 93164) (Acadian-Pontchartrain study unit, Plate 6, Fig. 11). This organism should probably be identified as N. cariocincta (Lange-Bertalot, 1993). This name, however, was introduced by Lange-Bertalot as a manuscript name and no formal protologue of N. cariocincta has yet been published. Meanwhile, this taxon should be referred to as Navicula sp. 27 NAWQA KM. Navicula sp. 2 (NADED # 93165) (Acadian-Pontchartrain study unit, Plate 6, Figs. 1 and 2). This taxon seems to be closely related to Navicula kriegerii. The nature and arrangement of the striae are similar in both taxa, but the raphe is more conspicuous in N. sp. 2. N. Roberts counted organisms such as the ones depicted in Plate 6, Figs. 1 and 2 as Navicula tugelae. The name Navicula cf. krigerii should be used for this taxon in future NAWQA counts. Navicula sp. OB UL NAWQA KM (NADED # 46687) (Plate 6, Figs. 7-10) previously treated during the Fourth Workshop (see Morales, 2001 pg. 12, Plate 12, pg. 28). This taxon should be identified as N. canalis (NADED # 46317). Gomphonema sp. 1UL NAWQA WHIT KM (NADED # 37146) (Plate 6, Figs ). This taxon should now be identified as Gomphonema kobayasii (NADED # 37197). Other unknown taxa introduced in the ANSP diatom taxa table and ANSP Algae image database should also be identified as G. kobayasii. These taxa are the following: Gomphonema cf. clevei CODY Fricke (NADED # 37129), Gomphonema sp. OG UL NAWQA 96 KM (NADED # 37141). During the Fourth Workshop, K. Manoylov presented several pictures of an unidentified taxon from the Arcadian-Pontchartrain NAWQA Study Unit. It was then decided that this taxon should be identified as Gomphonema patrickii (Morales, 2001, pg. 11, Plate 11, Figs. 8-12). We maintain this decision and include pictures of this taxon in this report as well (Plate 6, Figs ). Gomphonema sp. 2 (NADED # 37273) (Upper Illinois River study unit, Plate 6, Figs ). No equivalent has been found in the literature for this taxon. This taxon should be identified as Gomphonema sp. 8 NAWQA KM in the future. Gomphonitzschia sp. 1 (NADED # 83005) (Acadian-Pontchartrain study unit, Plate 6, Fig. 24). The valve depicted here in the mentioned figure shares features with other Gomphonizschia species, especially the marked heteropolarity of the valve. This taxon should be identified as Gomphonitzschia sp. 1 NAWQA KM in future NAWQA counts. THE ACADEMY OF NATURAL SCIENCES 12 PATRICK CENTER FOR ENVIRONMENTAL RESEARCH

14 K. Manoylov also presented an unknown naviculoid diatom found in the Arcadian- Pontchartrain NAWQA Study Unit (Plate 6, Fig. 18). This organism should be identified as Haslea spicula. Cymbella sp. 1 (NADED # 23186) (Acadian-Pontchartrain study unit, Plate 6, Fig. 22). No published equivalent could be found for this organism and it should be identified as Cymbella sp. 5 NAWQA KM in future counts. Cymbella sp. 2 (NADED # 23187) (Acadian-Pontchartrain study unit, Plate 6, Fig. 23). No published equivalent could be found for this organism. This taxon should be referred to as Cymbella sp. 6 NAWQA KM. D. Winter presented a plate with unknown taxa and identifications for which she needed clarification and/or confirmation (Plate 8, Figs. 1-28). Plate 8, Figures 1-4 correspond to Navicula subminuscula, a taxon discussed during the Fourth Workshop (see Morales, 2001, pg. 9, Plate 8, Figs. 1-11). Plate 8, Figures 5-14 were presented during the fifth workshop as Navicula sp. 1 (Great Salt Lake Study Unit). This taxon should be identified as N. menisculus var. obtusa (Simonsen, 1987, Plate 329, Figs. 25 and 26). During the Fourth Workshop participants had determined that the occurrence of N. meniculus var. obtusa in NAWQA had to be reviewed since only a few records of this taxon where present until then. This records are now confirmed for D. Winter found a large population in the Great Salt Lake Study Unit. Plate 8, Figures correspond to Navicula menisculus var. grunowii, a taxon discussed during the Fourth Workshop (Morales, 2001, pg. 8, Plate 6, Figs. 9-15). Plate 8, Figures 18 and 19 correspond to Navicula reichardtiana, a taxon discussed in detail previously in the present report. Plate 8, Figures 20 and 21 should be identified as Navicula cryptotenella. Plate 8, Figures 22 and 24 correspond to Navicula gregaria. Plate 8, Figure 24 corresponds to Navicula veneta. The three latter taxa were discussed during the Fourth Workshop (Morales, 2001). D. Winter also presented pictures of Encyonema hebridicum from the ANSP White River Project (Plate 8, Figs ). K. Ponader presented a picture from New Jersey Piedmont streams (Plate 8, Fig. 21). This specimen was first identified as Gomphonema sp. 1 NEW JERSEY KCP, but it should be identified as Gomphonema christenseni (Lowe and Kociolek, 1984, Figs , pg. 475). THE ACADEMY OF NATURAL SCIENCES 13 PATRICK CENTER FOR ENVIRONMENTAL RESEARCH

15 REFERENCES Andresen, N.A., E.F. Stoermer and R.G. Kreis, Jr New nomenclatural combinations referring to diatom taxa which occur in The Laurentian Great Lakes of North America. Diatom Research 15: Barber, H.G. and E.Y. Haworth A Guide to the Morphology of the Diatom Frustule. Freshwater Biological Association. Scientific Publication No. 44. Titus Wilson & Son Ltd. England. 112 pp. Bukhtiyarova, L. and F.E. Round Revision of the genus Achnanthes sensu lato. Psammothidium, a new genus based on A. marginulatum. Diatom Research, 11: Cholnoky, B.J Neue und seltene Diatomeen aus Afrika II. Diatomeen aus dem Tugela- Gebiete in Natal. Osterr. Bot. Z. 103: Clason, T.A. and D.F. Charles First NAWQA Diatom Taxonomy Harmonization Workshop. Patrick Center for Environmental Research. The Academy of Natural Sciences of Philadelphia. Report No Second NAWQA Diatom Taxonomy Harmonization Workshop. Patrick Center for Environmental Research. The Academy of Natural Sciences of Philadelphia. Report No Compère, P Taxonomic revision of the diatom genus Pleurosira (Eupodiscaceae). Bacillaria 5: Cox, E.J Placoneis Mereschkowsky: the re-evaluation of a diatom genus originally characterized by its chloroplast type. Diatom Research 2: Identification of Freshwater Diatoms from Live Material. Chapman & Hall. England. 158 pp. Dawson, P.A Observations on diatom species transferred from Gomphonema CV. A. Agardh to Gomphoneis. Br. Phycol J. 9: Ehrenberg, C.G Über ein fossilen Infusorien bestehendes, 1832 zu Brod verbackenes Bergmehl von der Grenzen Lapplands in Schweden. Ber. Bekanntm. Verh. Königl. Preuss. Akad. Wiss. Berlin. 1836: Flower, R.J., V.J. Jones and F.E. Round The distribution and classification of the problematic Fragilaria (virescens v.) exigua Grun./Fragilaria exiguiformis (Grun.) Lange-Bertalot: a new species or a new genus? Diatom Research 11: THE ACADEMY OF NATURAL SCIENCES 14 PATRICK CENTER FOR ENVIRONMENTAL RESEARCH

16 Hamilton, P.B., M. Poulin, D.F. Charles and M. Angeli Americanarum Diatomarum Exsiccata: Cana, voucher slides from eight acidic lakes in northeastern North America. Diatom Research 7: Hartley, B A check-list of the freshwater, brackish and marine diatoms of the British Isles and adjoining coastal waters. Journal of the Marine Biological Association, U.K. 66(3): Hustedt, F Die Diatomeenflora des Küstengebietes der Nordsee vom Dollart bis zur Elbemündung. I. Die Diatomeenflora in den sedimenten der unteren Em sowie auf den Watten in der Leybucht, des Memmert und bei der Insel Juist. Abh. Naturw. Ver. Bremen 31: Kingston, J.C New combinations in the freshwater Fragilariaceae and Achnanthidiaceae. Diatom Research 15: Kociolek, J.P. and J.C. Kingston Taxonomy, ultrastructure, and distribution of some gomphonemoid diatoms (Bacillariophyceae: Gomphonemataceae) from rivers in the United States. Canadian Journal of Botany 77: Krammer, K Morphologic and taxonomic investigations of some freshwater species of the diatom genus Amphora Ehr. Bacillaria 3: Die cymbelloiden Diatomeen- Eine Monographie der weltweit bekannten Taxa. Teil.1. Allgemeines und Encyonema Part. Bibliotheca Diatomologica 36: Krammer, K. and H. Lange-Bertalot Bacillariophyceae. 1. Teil: Naviculaceae. In: Ettl, H., Gerloff, J., Heynig, H. & Mollenhauer, D. (Eds.). Süsswasserflora von Mitteleuropa. 2(1): Gustav Fisher Verlag, Germany Bacillariophyceae. 2. Teil: Bacillariaceae, Epithemiaceae, Surirellaceae. In: Ettl, H., Gerloff, J., Heynig, H. & Mollenhauer, D. (Eds.). Süsswasserflora von Mitteleuropa. 2(2): Gustav Fischer Verlag. Germany Bacillariophyceae. 4. Teil: Achnanthaceae. Kritische Ergänzungen zu Navicula (Lineolatae) und Gomphonema. In: H. Ettl, J. Gerloff, G. Gärtner, H. Heynig and D. Mollenhauer, eds. Süsswasserflora von Mitteleuropa. 2(4): Gustav Fisher Verlag, Germany. Lange-Bertalot, H Neue Taxa und über 100 weitere neu definierte Taxa ergänzend zur Sü$wasserflora von Mitteleuropa Vol. 2/1-4. Bibliotheca Diatomologica 27: Lange-Bertalot, H. and S.I. Genkal Diatoms from Siberia I. Islands in the Arctic Ocean (Yugorsky-Shar Strait). Iconographia Diatomologica 6: THE ACADEMY OF NATURAL SCIENCES 15 PATRICK CENTER FOR ENVIRONMENTAL RESEARCH

17 Lange-Bertalot, H. and D. Metzeltin Oligotrophie-Indikatoren. 800 Taxa repräsentativ für drei diverse Seen-Typen Kalkreich-Oligodystroph-Schwach gepuffertes Weichwasser. Iconographia Diatomologica 2: Lange-Bertalot, H. and G. Moser Brachysira. Monographie der Gattung. Bibliotheca Diatomologica 29: Lange-Bertalot, H., D. Metzeltin and A. Witkowski. 1996a. Hippodonta gen. nov. Umshreibung und Bergründung einer neuen Gattung der Naviculaceae. Iconographia Diatomologica 4: Lange-Bertalot, H., K. Külbs, T. Lauser, M. Nörpel-Schempp.and M. Willmann. 1996b. Dokumentation und revision der von Georg Krasske beschriebenen Diatomeen-Taxa. Iconographia Diatomologica 3: Lowe, R.L. and J.P. Kociolek New and rare diatoms from Great Smoky Mountains National Park. Nova Hedwigia 39: Mann, D.G The diatom genus Sellaphora: separation from Navicula. Br. Phycol. J. 24: Meister, F Kisselalgen aus Asien. Berlin. 56 pp. Merino, V., J. García, M. Hernández-Mariné and M. Fernández Morphology and ultrastructure of Gomphoneis rhombica (Fricke) comb. nov. Diatom Research 9: Metzeltin, D. and A. Witkowski Diatomeen der Bären-Insel. Iconographia Diatomologica 4: Morales, E.A Fourth NAWQA Diatom Taxonomy Harmonization Workshop. Patrick Center for Environmental Research. The Academy of Natural Sciences of Philadelphia. Report No F. Morales, E.A. and M. Potapova Third NAWQA Diatom Taxonomy Harmonization Workshop. Patrick Center for Environmental Research. The Academy of Natural Sciences of Philadelphia. Report No Patrick, R. and C.W. Reimer The Diatoms of the United States. Exclusive of Alaska and Hawaii. Vol. 1. Monographs of the Academy of Natural Sciences of Philadelphia pp. Rabenhorst, L Die Süßwasser-Diatomaceen (Bacillarien) für Freunde der Mikroskopie. Leipzig. 72 pp. THE ACADEMY OF NATURAL SCIENCES 16 PATRICK CENTER FOR ENVIRONMENTAL RESEARCH

18 Flora europaea algarum aquae dulcis et submarinae. Vol. 1, Sectio 1: Algas diatomeas complectens. Leipzig, Germany. 359 pp. Reichardt, E Taxonomische Revision des Artenkomplexes um Gomphonema pumilum (Bacillariophyceae) Nova Hedwigia 65: Round, F.E. and P.W. Basson A new monoraphid diatom genus (Pogoneis) from Bahrain and the transfer of previously described species A. hungarica & A. taeniata to new genera. Diatom Research 12: Round, F.E. and L. Bukhtiyarova Four new genera based on Achnanthes (Achnanthidium ) together with a re-definition of Achnanthidium. Diatom Research 11: Round, F.E. and D.G. Mann The diatom genus Brachysira. I. Typification and separation from Anomoeoneis. Archiv Protistenkunde 124: Round, F.E., R.M. Crawford and D.G. Mann The Diatoms: Biology and Morphology of the Genera. Cambridge University Press. 747 pp. Rumrich, U., H. Lange-Bertalot and M. Rumrich Diatomeen der Anden. Von Venezuela bis Patagonien/Feuerland Und Zwei weitere Beiträge. Iconographia Diatomologica 9: Simonsen, R Atlas and Catalogue of the Diatom Types of Friedrich Hustedt. Vol. I: Catalogue, Vol. II: Atlas, Plates Vol III: Atlas, Plates J. Cramer Berlin/Stuttgart, Germany. Snoeijs, P.J.M Studies in the Tabularia fasciculata complex. Diatom Research 7: Van Heurck, H. ( ). Synopsis des Diatomées de Belgique. Atlas, Tafel 1-30 (1880); Tafel (1882); Tafel (1883); Tafel A, B, C (1885). Anvers, Belgium. Williams, D.M Morphology, taxonomy and inter-relationships of the ribbed araphid diatoms from the genera Diatoma and Meridion (Diatomaceae: Bacillariophyta). Bibliotheca Diatomologica 8: Fragilaria floridiana Hanna: ultrastracture of the valve and girdle and its transference to Fragilariforma Williams & Round. In: Ricard, M. (Ed.). Ouvrage dédié à la Mémorie du Professeur Henry Germain ( ). p Koeltz, Germany. Williams, D.M. and F.E. Round Revision of the genus Synedra Ehrenb. Diatom Research 1: Revision of the genus Fragilaria. Diatom Research 2: THE ACADEMY OF NATURAL SCIENCES 17 PATRICK CENTER FOR ENVIRONMENTAL RESEARCH

19 Plate 1. Figures 1-8. Navicula caterva (Type population A-G.C ). Figures Navicula reichardtiana (Sacramento River, Sacramento Basin Study Unit). Figures Navicula odiosa. Figure 12 corresponds to the Type specimen (A-G.C. 6853a). Figures correspond to specimens from the type population. Figures 16 and 17. Navicula incertata (Caloosahatchee River, Southern Florida Study Unit). Figures Navicula kotschyi (Black Warrior River, Mobile River Basin Study Unit). Figures Navicula savannahiana. Figures 29 and 30 depict the type specimen at different focusing points. The rest of the figures depict specimens from the type population (A- G.C. 4737a). N. savannahiana should be identified as N. kotschyi in NAWQA material (see text for explanation). Figures Navicula texana. Figure 34 corresponds to the type specimen, all the rest depict specimens in the type population (A-G.C. 6587a). N. texana should be identified as N. kotschyi in NAWQA material (see text for explanation). Photographs: E. Morales. THE ACADEMY OF NATURAL SCIENCES 18 PATRICK CENTER FOR ENVIRONMENTAL RESEARCH

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21 Plate 2. Figures Navicula cf. kotschyi MORALES Grunow (Iroquois River, Upper Illinois Study Unit). This taxon was presented as N. kotschyi during the Fifth Workshop, but it should be kept separate from N. kotschyi and assigned the NADED number: in subsequent counts. Photographs: K. Manoylov. THE ACADEMY OF NATURAL SCIENCES 19 PATRICK CENTER FOR ENVIRONMENTAL RESEARCH

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23 Plate 3. Figures 1-7. Navicula aikenensis. Figure 2 corresponds to the type specimen, all the rest depict specimens from the type population (A-G.C. 4737a). Figures 8 and 9. Navicula aff. tugelae NAWQA MP Cholnoky (Figure 8: Bear Creek; Figure 9: Great Swamp, Albermale-Pamilco Study Unit). Figure 10. N. tugelae. Original drawing presented by Cholnoky (1959). Figures Navicula lateropunctata (Type population A-G.C a). Figures N. lateropunctata (Figure 19: Devils Cradle Creek, Albermale-Pamilco Study Unit; Figures 20, 23 and 24: Truck E River, Apalachicola-Chattahoochee-Flint River Basin; Figure 21: Mocassin Creek, Albermale- Pamilco Study Unit; Figure 22: Contentnea Creek, Albermale-Pamilco Study Unit). Figures N. sanctaecrucis (Type population A-G.C. 8116). Photographs M. Potapova and D. Winter. THE ACADEMY OF NATURAL SCIENCES 20 PATRICK CENTER FOR ENVIRONMENTAL RESEARCH

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25 Plate 4. Figure 1. Navicula schroeteri. Original diagram presented by Meister (1932). Scanned by T. Clason. Figure 2. Navicula schroeteri var. escambia (Type specimen A- G.C ). Figure 3. Navicula symmetrica (Type specimen A-G.C 25740). Figures N. schroeteri var. escambia (Type population). Figures N. symmetrica (Cub River, Great Salt Lake Basin Study Unit). Photographs: E. Morales. THE ACADEMY OF NATURAL SCIENCES 21 PATRICK CENTER FOR ENVIRONMENTAL RESEARCH

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27 Plate 5. Figures 1-6. Navicula viridula var. rostellata (Tombigbee River, Mobile River Basin Study Unit). Figures 4-6 depict organisms placed in Navicula amphiceropsis by Lange- Bertalot and Rumrich (Rumrich et al., 2000), but that should be kept in N. viridula var. rostellata in NAWQA studies. Figures N. viridula var. rostellata (New Jersey, Raritan River, North Branch). Figures Navicula germainii (Tombigbee River, Mobile River Basin Study Unit). Figures N. germainii (New Jersey, Figures 27-34: Raritan River, North Branch; Figures 35 and 36: Dead River). Photographs: 1-6 and E. Morales; 7-17 and K. Ponader. THE ACADEMY OF NATURAL SCIENCES 22 PATRICK CENTER FOR ENVIRONMENTAL RESEARCH

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29 Plate 6. Figures 1 and 2. Navicula cf. kriegerii KM Krasske (Tchefuncte River, Acadian- Pontchartrain Study Unit). This taxon has been called N. tugelae in past NAWQA counts. Figures 3 and 4. Navicula ruttneri var. capitata (Waihee Stream, Oahu Study Unit). Figure 5. Navicula sp. 26 NAWQA KM (NAWQA GSN22812?). Figure 6. Navicula sp. 25 NAWQA KM (Tennesse River, Lower Tennesse River Study Unit). Figures Navicula canalis presented during the Third and Fourth Workshops as Navicula sp. OB UL NAWQA 96 KM. Figure 11. Navicula sp. 27 NAWQA KM (Bayou Liberty Acadian-Pontchartrain Study Unit). This taxon should be identified as N. cariocincta once this name is validly published. Figures Gomphonema kobayasii. This taxon has also been identified as Gomphonema sp. 1 UL NAWQA WHIT KM, Gomphonema sp. OG UL NAWQA 96 KM and Gomphonema cf. clevei CODY Fricke in past NAWQA counts. Figures Gomphonema patrickii (Archadian-Pontchartrain Study Unit). Figure 18. Haslea spicula (Archadian- Pontchartrain Study Unit). Figures Gomphonema sp. 8 NAWQA KM (Iroquois River, Upper Illionis River Study Unit). Figure 22. Cymbella sp. 5 NAWQA KM (Pass Manchac, Acadian-Pontchartrain Study Unit). Figure 23. Cymbella sp. 6 NAWQA KM (Pass Manchac, Acadian-Pontchartrain Study Unit). Figure 24. Gomphonitzshia sp. 1 NAWQA KM (Bayou Liberty, Acadian-Pontchartrain Study Unit). All pictures taken by K. Manoylov. THE ACADEMY OF NATURAL SCIENCES 23 PATRICK CENTER FOR ENVIRONMENTAL RESEARCH

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31 Plate 7. Figures 1-4. Navicula subminuscula (Cub River, Great Salt Lake Basin Study Unit. Figures Navicula menisculus var. obtusa (Emigration Creek, Great Salt Lake Basin Study Unit). Figures Navicula menisculus var. grunowii (Emigration Creek, Great Salt Lake Basin Study Unit). Figures 18 and 19. Navicula reichardtiana (Emigration Creek, Great Salt Lake Basin Study Unit). Figure 20 and 21. Navicula cryptotenella (Emigration Creek, Great Salt Lake Basin Study Unit). Figures 22 and 23. Navicula gregaria (Emigration Creek, Great Salt Lake Basin Study Unit). Figures Encyonema hebridicum (White River, ANSP White River Project). Figure 29. Gomphonema christenseni (Raritan River, South Branch, ANSP New Jersey Project). Photographs: Figures 1-28 by D. Winter; Figure 29 by K. Ponader. THE ACADEMY OF NATURAL SCIENCES 24 PATRICK CENTER FOR ENVIRONMENTAL RESEARCH

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