Cárdenas, P.; Moore, J.A. (2019). First records of Geodia demosponges from the New England seamounts, an opportunity to test the use of DNA mini-barcodes on museum specimens. Marine Biodiversity. 49 (1): 163-174.
We report the first records of the sponge genus Geodia (Demospongiae, Tetractinellida, Geodiidae) from the New England Seamounts and Muir Seamount, at lower bathyal depths. Nine specimens collected between 2000 and 2005 belong to two boreal species (Geodia macandrewii and Geodia barretti) and a temperate species (Geodia megastrella). These records extend the distributions of these deep-sea amphi-Atlantic species to the west. Most of these specimens were originally fixed in formalin, which substantially degraded the DNA. We nonetheless managed to sequence two cytochrome c oxidase subunit I (COI) mini-barcodes: the universal mini-barcode at the 5' end of the Folmer barcode (130 bp) and a newly proposed mini-barcode at the 3' end of the Folmer barcode (296 bp). These mini-barcodes unambiguously confirmed our identifications. As an additional test, we also successfully sequenced these two mini-barcodes from the holotype of G. barretti, collected in 1855. We conclude by advocating the use of mini-barcodes on formalin-fixed or old specimens with degraded DNA.