Gingersrus Database Taxon ID 7780
CURRENT NAME: Costus sp. nov.
PROPOSED NAME: Costus douglasdalyi
NAME CHANGE NOTES: New species published March 22, 2023 in PhytoKeys 222: 75-127, similar to erythrothyrsus but with narrow leaves.
FULL SCIENTIFIC NAME: Costus douglasdalyi Maas & H.Maas
STATUS : sp. nov.
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Costus douglasdalyiwas published March 22, 2023 in PhytoKeys 222: 75-127 by Paul and Hiltje Maas. Paul Maas recognized that there is a discrete narrow leaf form of the species Costus erythrothyrsus that is common in the area around Cruzeiro do Sul, Acre, Brazil when he visited the region in the 1970's and he has now decided to describe it as a new species, to be named in honor of Doug Daly of the New York Botanical Garden who has done so much for research in western Brazil.
Paul selected as the type specimen a collection, Daly 8606, from the Rio TarauacÃ¡ in the state of Acre, Brazil. This new species is distinguished from Costus erythrothyrsus by having very narrow, linear leaves and often flowering from the base (as in the Daly type specimen) instead of terminal on a leafy shoot.
I visited the area around Cruzeiro do Sul in Acre in 2019, assisted by Dr. Marcus Athaydes of the federal university (UFAC, Cruz. do Sul campus). I went to sites where Dr. Maas has recorded this new species and made detailed measurements of the flower parts and took photos to assist him in the description. A few of these plants flowered at the base on leafless shoots, but mostly were terminal flowering plants on tall leafy stems. The leaves did not to me seem to be quite as narrow or on as small a plant as the Daly type specimen, but I showed the photos to Paul Maas and he identified them as this new species. I also collected leaf tissue (my R3479) from one of the sites where Paul had seen this new species (Rondon site of Croat 85008).
I have had much difficulty in distinguishing this new species from another new species that Paul Maas is describing called Costus pseudospiralis. That species also occurs in Acre, Brazil but apparently only from the more southerly parts of that Brazilian state, in the Rio Acre region.
DNA has been extracted from my sample near Cruzeiro do Sul and from Paul's sample of C. pseudospiralis from Beni, Bolivia. Both those samples were found to be in a clade close to samples of Costus acreanus. Additional sampling may be needed to obtain a clear delination of these species.
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