Journal of the Marine Biological Association of the United Kingdom

Research Article

Rediscovery and augmented description of the HMS ‘Challenger’ acorn worm (Hemichordata, Enteropneusta), Glandiceps abyssicola, in the equatorial Atlantic abyss

Nicholas D. Hollanda1 c1, Karen J. Osborna2, Andrey V. Gebruka3 and Antonina Rogachevaa3

a1 Marine Biology Research Division, Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California 92093 USA

a2 Department of Invertebrate Zoology, Smithsonian Institution, National Museum of Natural History, Washington, DC, 20013-7012

a3 P.P. Shirshov Institute of Oceanology, Russian Academy of Sciences, Moscow 117997, Russia


A 2009 oceanographic expedition of the Russian Academy of Sciences collected the anterior region of a single acorn worm (phylum Hemichordata, class Enteropneusta) by trawling at a depth of 5560 m in the Romanche Trench (equatorial Atlantic). The specimen was a ripe female with numerous, relatively small oocytes in each ovary. Phylogenetic analysis of rDNA sequences robustly placed the worm in the family Spengelidae. In addition, morphological features of the proboscis, collar, and anterior trunk region indicated that the worm was Glandiceps abyssicola, a species previously represented solely by the holotype, which had been dredged from the equatorial Atlantic in 1873 by the HMS ‘Challenger’ and subsequently sent to Germany for description by Spengel (1893). The holotype was presumably destroyed by World War II bombing; therefore, we here designate the Romanche Trench specimen as the neotype of G. abyssicola and supply an augmented species diagnosis.

(Received March 14 2013)

(Accepted May 19 2013)

(Online publication July 09 2013)


  • Hemichordata;
  • Enteropneusta;
  • Spengelidae;
  • Glandiceps abyssicola ;
  • neotype;
  • rDNA sequence;
  • phylogenetic analysis;
  • histology