Dubious as a valid name. ION doesn't have the name.
David Edward Russell 1987 is an unpublished thesis, and 1991 is only an abstract from the Copehagen IPC (not in front of me at the moment). So if only in those, I suggest this is an unavailable as unpublished name.
There is a web link: http://www.sealifebase.fisheries.ubc.ca/summary/Branchiosyllis-noviseta.html
but the citation there used to support the existence of the name (a tropical Pacific species list from Sergio) does NOT appear to contain the species name and Russell is not in the bibliography.
The 1987 thesis would appear to be the best place to go to see what entity was intended to be named.
From: annelida-bounces from oat.bio.indiana.edu [annelida-bounces from oat.bio.indiana.edu] on behalf of Jeffrey Alejandro Sibaja-Cordero [jeffro.alejandro from gmail.com]
Sent: 16 November 2013 06:46
To: Annelida from magpie.bio.indiana.edu
Subject: [Annelida] Branchiosyllis noviseta Russell
I need a description of the species Branchiosyllis noviseta or the correct
The species is not in the WORMS web page, but in several papers, the
species was mentioned as described by Russell 1987 or Russell 1991.
Dr. Jeffrey Alejandro Sibaja Cordero
Prof. Escuela de Biología, Universidad de Costa Rica
Investigador CIMAR & Museo Zoología UCR
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