Gingersrus Database Taxon ID 7849
Costus sp. Narupa White
CURRENT NAME: Costus possible sp. nov. unnamed
PROPOSED NAME: Costus sp. Narupa White
NAME CHANGE NOTES: Possible sp. nov., as yet undescribed and unnamed, some similarity to Costus arabicus
FULL SCIENTIFIC NAME: Costus L.
STATUS : sp. nov. unnamed
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I first saw this species in southern Colombia in 2018, and thought it might be a hybrid as I found it in only one small disturbed area along a petroleum pipeline. However, in 2022 I was in the Narupa area of Napo, Ecuador along the Rio HollÃn and found several other populations of it from the Rio HollÃn east to Hatun Sumako and south along the small road that leads to severa indigenous villages. It seems very unlikely that this is a recent hybrid.
The white flowers and bracts may at first seem similar to Costus arabicus, but it is not in a typical habitat for that species. It is distinguished most readily in the field by the inflated lower sheaths and the very long and deeply lobed ligules. The flowers have a much wider labellum than C. arabicus and the non-appendaged bracts are deeply convex in shape, much like the Costus sp. nov. convexus.
A partial phylogeny was completed by Eugenio Valderrama and his associates in the Chelsea Specht Lab at Cornell University and was published in the journal Frontiers in Plant Science in September 2022. The 2018 collection from Colombia was sampled for DNA and included in a phylogeny tree. It showed up in a clade with the orginal Costus 'El Gato' from Gualaquiza, Ecuador in a lineage very close to Costus sp. nov. convexus. It was far separated from Costus arabicus, so it seems that its appearance although superficially similar to that species is not closely related at all.
I am satisfied that this is a good new species, and with the collection of a type specimen it can be described and published as such.