Bassia bassensis
Quoy & Gaimard (1827)
Download a fact sheet for Bassia bassensis (PDF 392KB)
Taxonomy
| Phylum | Cnidaria |
| Class | Hydrozoa |
| Subclass | Hydroidolina |
| Order | Siphonophorae |
| Suborder | Calycophorae |
| Family | Abylidae |
| Genus | Bassia |
| Species | bassensis |
Size
- Anterior nectophore: up to 7 mm in height
- Posterior nectophore: up to 15 mm in length
- Eudoxid bract: up to 8 mm in height
Distinguishing characteristics
- Eudoxid and polygastric stages have 2 very dissimilar nectophores, posterior and anterior, both stages can be used for identification
- Nectophores are rigid, with ridges and no bumps
- The angular shaped anterior nectophore is smaller than the posterior nectophore, this is diagnostic
- Nectophores and eudoxids may have bluish tinge to ridges
- Polygastric stage
- Anterior nectophore
- Polyhedral
- The nectosac extends above the main body of the somatocyst
- No apical diverticulum to the stomatocyst
- The somatocyst is large and globular
- The hydroecium does not extend up between the nectosac and somatocyst
- Posterior nectophore
- Rectangular
- 4 main ridges which end in short basal teeth
- Eudoxid stage
- The phyllocyst is a long tube, swollen apically and without lateral processes
- The gonophore has 4 longitudinal ridges which end basally in minute teeth
Distribution
- Epipelagic, temperate waters
- Pacific, Indian and Atlantic Oceans, and Mediterranean Sea
Ecology
- Includes colonies with swimming bells (nectophore) but no float (pneumatophore)
- Long tubular stem extends from swimming bell, from which various zooids are budded in groups (called a cormidium)
- Cormidium consists of shield-like bract, gastrozooid, and one or more gonophores that may function as swimming bell
- Cormidium breaks loose from parent colony and starts independent eudoxid
- Feeds on copepods in the length range 0.4 to 1.2 mm
- Can have significant grazing impact on small copepods, both cyclopoids and calanoids
References
- Gibbons pers. comm. (2012)
- Marine species identification portal at http://species-identification.org/index.php
- Pages, F.; Gili, J.-M.; Bouillon, J. 1992 Medusae (Hydrozoa, Scyphozoa, Cubozoa) of the Benguela Current (southeastern Atlantic). Scientia Marina Volume: 56 Issue: Suppl. 1 Pages: 1-64
- Pages, F; Gonzalez, HE; Ramon, M; et al. 2001. Gelatinous zooplankton assemblages associated with water masses in the Humboldt Current System, and potential predatory impact by Bassia bassensis (Siphonophora : Calycophorae) MARINE ECOLOGY PROGRESS SERIES Volume: 210 Pages: 13-24 DOI: 10.3354/meps210013
- Pugh, P. R. (1999). Siphonophorae. South Atlantic Zooplankton. D. Boltovskoy. Leiden, The Netherlands, Backhuys Publishers. 1: 467-511