Spirobranchus lamarcki (Quatrefages, 1866)
Lamarck's keelworm - Gerichelde driekantkalkkokerworm
See * for identification
Yerseke, the Netherlands, 22-10-2016. In vitro photo specimen A, L: 15mm, 26-10-2016.
Yerseke, the Netherlands, 22-10-2016. In vitro photo specimen A, 26-10-2016.
Yerseke, the Netherlands, 22-10-2016. In vitro photo specimen A, 26-10-2016.
Yerseke, the Netherlands, 22-10-2016. In vitro photo specimen A, 26-10-2016.
Anna Friso, the Netherlands, 4-2-2017. In vitro photo specimen B, 8-2-2017.
* IDENTIFICATION
Identification of the two Spirobranchus species found in the Netherlands – S. triqueter and S. lamarcki - is rather difficult. Whenever you find a specimen with lateral keels on the tube, you always have to do with S. lamarcki. But S. lamarcki may have lateral keels (both specimens on this page lack these keels). Especially the ‘youngest’ part of the tube (where the worm comes out) may lack lateral keels. If only a medial keel is present, you have to study the operculum for precise identification.
I think the two specimens on this page are S. lamarcki**. When I look at the drawings and photographs of the operculums (see next photo's) of both species that I have at my disposal (see also the page of S. triqueter), I describe the difference as follows:
- the cap of S. lamarcki is built up higher, therefore the space between the fleshy ampulla and the calcareous end cap is greater,
- the cap of S. triqueter is less high, therefore the space between the fleshy ampulla and the calcareous end cap is smaller; the ampulla almost touches the end cap.
There are more differences between the species, but usually these are hardly discernible on photo's. In the end only DNA-testing provides full certainty!
**NB. Of the two specialists consulted, one of them indicated that specimen A could also be S. triqueter.
If no operculum can be seen in the photo, then it is one of the two species. For these specimens and if there is too much doubt (even if the operculum can be seen) I have created a ‘double species’ page.
Comment is welcome!
