skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.


Title: The phylogeny of the genus Nannochloropsis (Monodopsidaceae, Eustigmatophyceae), with descriptions of N. australis sp. nov . and Microchloropsis gen. nov .
Award ID(s):
1248291
PAR ID:
10039435
Author(s) / Creator(s):
; ;
Date Published:
Journal Name:
Phycologia
Volume:
54
Issue:
5
ISSN:
0031-8884
Page Range / eLocation ID:
545 to 552
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. Here we give names to three new species of Paraburkholderia that can remain in symbiosis indefinitely in the spores of a soil dwelling eukaryote, Dictyostelium discoideum . The new species P. agricolaris sp. nov. , P. hayleyella sp. nov. , and P. bonniea sp. nov . are widespread across the eastern USA and were isolated as internal symbionts of wild-collected D. discoideum . We describe these sp. nov. using several approaches. Evidence that they are each a distinct new species comes from their phylogenetic position, average nucleotide identity, genome-genome distance, carbon usage, reduced length, cooler optimal growth temperature, metabolic tests, and their previously described ability to invade D. discoideum amoebae and form a symbiotic relationship . All three of these new species facilitate the prolonged carriage of food bacteria by D. discoideum, though they themselves are not food. Further studies of the interactions of these three new species with D. discoideum should be fruitful for understanding the ecology and evolution of symbioses. 
    more » « less
  2. To address the taxonomic uncertainty of Sporolithon species named in the early to mid-20th century, targeted PCR sequencing was performed on eight historical type specimens and on recently collected specimens. Six type specimens amplified for the rbcL gene and were Sanger sequenced yielding sequences ranging in length from 118 to 280 base pairs (bp). One, S. australasicum, failed to amplify and another, S. howei, was amplified for the psbA gene yielding a sequence 544 bp in length. The 118 bp long rbcL sequence of the lectotype of S. crassiramosum showed that it is a later, heterotypic synonym of S. molle. The rbcL sequences of type specimens of S. episoredion, S. schmidtii, S. sibogae and S. timorense ranged from 118 to 228 bp, and each is a distinct species. The 544 bp long psbA sequence of S. howei is also unique. The 280 bp long rbcL sequence of the lectotype of S. durum did not match any sequence with that name in any public repository, including the previously published complete plastome and mitogenome sequences. However, it was identical in sequence to a specimen in GenBank from the southern coast of Western Australia as well as several other sequences generated from field-collected specimens from the states of South Australia and Western Australia. The rhodolith specimens from New Zealand previously called S. durum are S. nodosum sp. nov. The species is endemic to New Zealand. The epilithic specimens from New Zealand previously called S. durum are S. immotum sp. nov., which is also found along the southeastern coast of Australia. Sporolithon crypticum sp. nov. is described from the southern coast of Western Australia. RAxML and Bayesian phylogenetic analyses of Sporolithon psbA and rbcL sequences are congruent between the two plastid encoded genes. DNA sequencing of type specimens of species of corallines is demonstrated to be the only reliable method to correctly apply names. 
    more » « less
  3. Tomescu, Alexandru M.F. (Ed.)
    Premise of research: In our modern flora, the Cycadales represent one of the oldest-known gymnosperm clades, with their evolutionary roots tracing back to the late Paleozoic. Their radiation and wide distribution in the Mesozoic are well documented by numerous fossils. In contrast, the fossil record of late Paleozoic forms is restricted to a few specimens, thus leaving open questions on the origin and early evolution of cycads. A petrified stem with cycadalean affinity has been found in Saxony (central-eastern Germany) in Holocene gravel deposits of the Zwickauer Mulde river as a result of fluvial transportation from its original lower Permian locality. Methodology: The specimen was sectioned transversely, radially, and tangentially. Its provenance was clarified by comparing fossil woods of various localities in the upstream catchment area. Samples of these localities were exposed to ultraviolet light of different wavelengths, revealing distinctive fluorescence patterns related to specific geochemical conditions during the fossilization process. Plant anatomical studies were performed by macroscopic and microscopic documentation, including photo scanning, microscopic photography, and anatomical measurements. Pivotal results: Cycadodendron galtieri gen. nov. et sp. nov. originates from the Chemnitz Fossil Lagerstätte, an autochthonous floral assemblage of early Permian age (291 Ma; Sakmarian–Artinskian) that has been buried and conserved by pyroclastics in a geological instant. Several anatomical characteristics provide evidence for its cycadalean affinity: (1) a wide pith with numerous scattered medullary bundles, (2) a pith-peripheral vascular system with endarch primary xylem bundles, (3) at least nine successive vascular segments with secondary xylem and phloem, (4) araucarioid-type pitting of secondary xylem tracheids, and (5) primary rays and medullary bundles traversing the vascular segments. Conclusions: Cycadodendron galtieri gen. nov. et sp. nov. provides insights into stem anatomical characteristics of the oldest-known cycads, for example, revealing that polyxyly was an early-derived feature in cycad evolution. Its provenance reveals that the arborescent but generally small taxon was part of intramontane forested landscapes thriving on a well-drained mineral substrate in an alluvial plain setting and experiencing seasonally dry paleoclimate. 
    more » « less
  4. Abstract Marine N2-fixing cyanobacteria, including the unicellular genus Crocosphaera, are considered keystone species in marine food webs. Crocosphaera are globally distributed and provide new sources of nitrogen and carbon, which fuel oligotrophic microbial communities and upper trophic levels. Despite their ecosystem importance, only one pelagic, oligotrophic, phycoerythrin-rich species, Crocosphaera watsonii, has ever been identified and characterized as widespread. Herein, we present a new species, named Crocosphaera waterburyi, enriched from the North Pacific Ocean. C. waterburyi was found to be phenotypically and genotypically distinct from C. watsonii, active in situ, distributed globally, and preferred warmer temperatures in culture and the ocean. Additionally, C. waterburyi was detectable in 150- and 4000-meter sediment export traps, had a relatively larger biovolume than C. watsonii, and appeared to aggregate in the environment and laboratory culture. Therefore, it represents an additional, previously unknown link between atmospheric CO2 and N2 gas and deep ocean carbon and nitrogen export and sequestration. 
    more » « less