A protective shell around the larval cocoon of Cephalodiscus densus Andersson, 1907 (Graptolithoidea, Hemichordata)

Within the framework of the Italian XVII PNRA expedition (austral summer 2001-2002), several colonies of the Graptolithoidea (=Pterobranchia+Graptolithina) species, Cephalodiscus densus Andersson and C. hodgsoni Ridewood, were collected by trawl from Tethys Bay (Terra Nova Bay, Ross Sea). These orga...

Full description

Saved in:
Bibliographic Details
Published in:Polar biology 2004-11, Vol.27 (12), p.813-817
Main Authors: SCHIAPARELLI, S, CATTANEO-VIETTI, R, MIERZEJEWSKI, P
Format: Article
Language:English
Subjects:
Aquariums
Biological and medical sciences
Documentation
Fundamental and applied biological sciences. Psychology
Invertebrates
Larvae
Less representative or incertae sedis groups: acanthocephala, chaetognatha, gnathostomulida, lophophoria, merostomata, mesozoa, myxozoa, nematorhyncha, pararthropoda, placozoa, priapuloidea, prochordata, pycnogonida, rotifera
Signatures
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Within the framework of the Italian XVII PNRA expedition (austral summer 2001-2002), several colonies of the Graptolithoidea (=Pterobranchia+Graptolithina) species, Cephalodiscus densus Andersson and C. hodgsoni Ridewood, were collected by trawl from Tethys Bay (Terra Nova Bay, Ross Sea). These organisms were maintained in aquaria for 2 weeks and their behaviour observed. The dissection of some colonies of C. densus allowed the reconstruction of the eggs' fate and the documentation of the formation of a protective shell around the cocoons of larvae settled within the "parental" colony encasement. The shell is produced by cementing size-selected debris, either of organic or inorganic origin, accumulated inside the encasement. This is the first documentation of such a structure within living Hemichordata and it helps to reinterpret some of the "resting structures" within zooidal tubes or thecae of particularly well-preserved fossil graptolites.[PUBLICATION ABSTRACT]
ISSN:0722-4060
1432-2056
DOI:10.1007/s00300-004-0661-x