New Species

Itasca State Park Microbial Observatory, Minnesota

Arrowwood National Wildlife Refuge, North Dakota

This page is constantly in development -- many more new species yet to come!!!

Through our work in Itasca and elsewhere we have discovered many potentially new species of coccoid and flagellate microalgae.  However, it is often quite difficult to demonstrate that these organisms are, in fact, new species.  The main problem is that the taxonomy of many of the algal groups that we work with is very confused.  Very few of the named genera have been examined using sequence analysis and those that have been examined have usually been shown to be polyphyletic, often including species from different classes.  However, we can use this page to show you our "works in progress."  These organisms are ones that we believe to be new species, but often additional species from culture collections will need to be investigated before we can definitively show that they are new species.

Unidentified Chlorophyceae

Itas 9/21 14-1d

This coccoid is related to Pseudomuriella, but perhaps only distantly so.  The prominent vacuole is an outstanding feature of this completely spherical organism.  Our only isolate is from the phytoplankton of Lake Itasca.  18S rDNA sequence - GenBank AY195974

Gloeotila sp. (Trebouxiophyceae)


Isolate JL11-10, isolated from Jim Lake, Arrowwood National Wildlife Refuge, North Dakota.  Although often single-celled, this organism can form short chains in a thin mucilage.  Division is by binary fission, instead of autosporulation, which is typical for many of our organisms.  No flagellate cells have been observed.  Analysis of 18S rDNA sequences indicates that this organism is closely related to Gloeotila contorta.   18S rDNA sequence - GenBank AY195976

Meyerella planktonica M. Fawley and K. Fawley (Trebouxiophyceae)

Itas 2/24 S-12w

This is a new genus and species, closely related to Chlorella.  However, Meyerella lacks a pyrenoid, which is always present in Chlorella. Sequence analysis shows that Meyerella is a separate lineage basal to the true Chlorella lineage in the Trebouxiophyceae. We have numerous isolates of this organism from Lake Itasca, but have not found it from any other Itasca site.  We have found this organism from Arrowwood, also. Meyerella is named for Rick Meyer, in honor of his excellent work with Itasca algae. Isolate shown, Itas 2/24 S-12w.  18S rDNA sequence - GenBank AY195973

Unnamed coccoid (Chlorophyceae)

Mary 6/3 D-3d

This interesting organisms is a coccoid member of the Hydrodictyaceae, which includes the familiar genus, Pediastrum.  During reproduction, it divides into small spherical cells that initially have rudimentary flagella. The daughter cells are then released from the mother cell in a vesicle, which ultimately gelatinizes. This organism represents the first unicellular member of the Hydrodicyaceae. Itasca isolate Mary 6/3 D-3d, from just below the thermocline in Mary Lake. 18S rDNA sequence - GenBank AY195984

Unidentified coccoid (Chlorophyceae)

Mary 9/21 T-3w

This zoosporic coccoid is spherical, with a cell structure that somewhat resembles Tetracystis. 18S rDNA sequence analysis indicates that its nearest relatives are Characiopodium and Neochloris species. However, the 18S rDNA sequence of this isolate differs from the most similar published sequence (Characiopodium hindakii) by 49 substitutions! There are several similar coccoid organisms that have been named, but for which no sequence data are available, so much work needs to be done before this organism can be named. Itasca isolate Mary 9/21 T-3w, from the tychoplankton of Mary Lake. rDNA sequence - GenBank AY197622

Pseudodictyosphaerium spp. (Chlorophyceae) and similar organisms from Itasca

Itas 2/24 S-8d Itas 6/3 M-2w

Mary 9/21 BT-15w Tow 6/3 P-1w

Itas 9/21 S-3w

We have many isolates of this organism from Lake Itasca, 2 isolates from Mary Lake, and 1 from Tower Pond. The morphology is quite variable, as can be seen from the pictures. Most isolates from Lake Itasca have cell size and colony formation consistent with Pseudodictyosphaerium, but a few lack the remnants of the mother cell walls that form the distinct connections between the cells. These isolates can be identified as Korshpalmella spp. The isolates from deep water samples from Mary Lake can also be identified as Korshpalmella. The single isolate from Tower Pond is comprised of mostly single cells, with some cells held together loosely by mucilage, a sort of intermediate form between Korshpalmella and Mychonastes. However, all of these isolates from Itasca possess the same 18S rDNA sequence and the same rbcL sequence. 18S rDNA sequence of "Mychonastes sp." Tow 6/3 P-1w - GenBank AY197637

Mychonastes spp. (Chlorophyceae) from ANWR

 AN 2/29-3, Mychonastes sp.  

JL 1/12-12, Mychonastes sp. AS 7-9, Mychonastes cf. homosphaera

Mychonastes spp. were commonly isolated from the Arrowwood lakes during the winter.  The winter isolates were of two types, represented by AN 2/29-3 and JL 1/12-12.  Our single warm-water isolate of Mychonastes is AS 7-9, isolated in July, which has an 18S rDNA sequence identical to M. homosphaera.  All of these isolates are always unicellular, as compared to related Itasca isolates, which always have at least some tendency to form colonies.  The 18S rDNA sequences of all three types are distinct.  Because only a single Mychonastes species has been named, M. homosphaera, AN 2/29-3 and JL 1/12-12 represent new species.  AN 2/29-3 18S rDNA sequence -- GenBank AY195965; JL 1/12-12 18S rDNA sequence - GenBank AY195978; AS 7-9 18S rDNA sequence - GenBank AY195971

Scenedesmus relative (Chlorophyceae)

 Mary 9/21 BT-16w

This coccoid reproduces by autospores and is notable for its thick mother cell wall with obvious knobs or bumps.  Analysis of 18S rDNA sequence data indicates a close relationship with the coenobial genus Scenedesmus and the unicellular genus Neodesmus.  We are not aware of any described organism with these characteristics.  We have two isolates of this organism, both collected from Mary Lake from below the thermocline.  18S rDNA sequence - GenBank AY197621

Chlorella sp. (Trebouxiophyceae)

Pic 9/21 P-1w

We have several coccoids that are in the "true" Chlorella lineage.  We have one isolate of this organism, from Picnic Pond (our "eutrophic" site).  The spherical cells possess pyrenoids and reproduce by autosporulation.  This organism would undoubtedly have been called Chlorella vulgaris by light microscopy, but the18S rDNA sequence differs from that of any named Chlorella sp. by 18 substitutions.  18S rDNA sequence - GenBank AY197630

"Chlorella" sp. (Trebouxiophyceae)

Mary 9/21 BT-10w

This organism has features typical of a Chlorella sp., but18S rDNA sequence analysis indicates that it is actually basal to the Chlorella vulgaris lineage, perhaps representing a new genus.  The pyrenoids are prominant and the number of autospores highly variable.  This is the only isolate of this organism that we have, from Mary Lake below the thermocline.  18S rDNA sequence - GenBank AY197620

"Chlorella" sp. (Trebouxiophyceae)

NDem 9/21 T-13d

This organism is rather different in appearance from typical Chlorella species.  Analysis of 18S rDNA data also places this organism at the base of the Chlorella vulgaris lineage.  This is the largest organism that we have isolated that is closely related to Chlorella.  We have three isolates of this alga, all from the same collection of North Deming Pond tychoplankton.  18S rDNA sequence - GenBank AY197628

Choricystis spp. (Trebouxiophyceae)

Pic 8/18 P-11w

The green algal genus Choricystis comprises perhaps 15-20 different "species" from our study sites in Itasca and Arrowwood, despite the fact that only one species is presently recognized in the literature.  These "species" can be differentiated by both 18S rDNA sequence and rbcL sequence.  Unfortunately, they all look pretty much alike.  These are the smallest organisms that we have isolated; smaller even than the Nannochloris relatives that we have from Arrowwood.  18S rDNA sequence for Pic 8/18 P-11w - GenBank AY197629

Unidentified alga (Chlorophyceae)

Tow 2/24 P-12d

This somewhat sarcinoid alga is a coccoid member of the Chlorophyceae. Although there are several organisms, such as Tetracystis spp., with this basic morphology, we have not yet been able to place this isolate in any known species or even genus.  The 18S rDNA sequence of this isolate differs from the most similar sequence in GenBank by 100 substitutions.  18S rDNA sequence - GenBank AY197633

Desmodesmus relatives (Chlorophyceae)

Tow 9/21 P-13w  Tow 2/24 P-8w

Tow 9/21P-14w  MLO-4

These are just some of our isolates that are actually embedded in the Desmodesmus lineage.  Based on analyses of 18S rDNA data, all of these isolates should be classified as Desmodesmus species.  Tow 2/24 P-8w has the appearance of a Didymocystis species and MLO-4 is a single celled organism with surface warts.  18S rDNA sequences:  Tow 9/21 P-13w - GenBank AY197638; Tow 2/24 P-8w - GenBank AY197634; Tow 9/21 P-14w - GenBank AY197639; MLO-4 - GenBank AY197627.  Recent ITS sequencing has identified MLO-4 as the newly named, Desmodesmus ultrasquamatus.

Closteriopsis relative (Trebouxiophyceae)


Analysis of 18S rDNA sequence data places this coccoid in the lineage of Closteriopsis, a fusiform green alga with multiple pyrenoids which is itself related to Chlorella kessleri.  The morphology of this organism is obviously very different, being spherical instead of needle-shaped.  However, this alga does have numerous small pyrenoids, which may be the link to Closteriopsis.  We are not aware of any described coccoid green algae with numerous small pyrenoids.  18S rDNA sequence - GenBank AY197625

Chlorella kessleri relative (Trebouxiophyceae)


This spherical coccoid is related to Chlorella kessleri.  Three isolates of this alga have been characterized, all from Arrowwood Lake, ANWR.  18S rDNA sequence - GenBank AY195967

Chlamydopodium relative (Chlorophyceae)

Pic 8/18 P-17w

This very large coccoid reproduces by autosporulation under our standard conditions, but is likely to produce zoospores if conditions are correct.  Analysis of 18S rDNA sequence data shows that this organism is closely related to Chlamydopodium and Pleurastrum in the Chlamydomonadales.  We only have one isolate of this organism, from Picnic Pond in Itasca. 18S rDNA sequence -GenBank AY220091

Chlamydomonas reinhardtii relative (Chlorophyceae)

WTwin 8/18 P-5d

This chlamydomonad typically reproduces by autosporulation.  It is probably our isolate that is most closely related to Chlamydomonas reinhardtii.  The cup-shaped plastid and basal pyrenoid clearly place this isolate in the Euchlamydomonas subgenus, but we have not been able to identify any described species with the additional features of this isolate, especially the small size. 18S rDNA sequence - GenBank AY220084

Unidentified Chlamydomonad (Chlorophyceae)

NDem 9/21 T-14w

This spherical chlamydomonad reproduces by autosporulation, although it is possible that zoospores may be produced under some conditions.  Although young cells superficially resemble a Euchlamydomonas-type cell, no eyespot can be found.  Older cells have a more reticulate plastid.  Analysis of 18S rDNA sequences indicates that this organism may be related to Protosiphon, Spongiochloris, and Ascochloris.  18S rDNA sequence - GenBank AY220089

Coming soon!  New species of Desmodesmus identified from the Itasca MO, including Desmodesmus itascaensis.