Morphological features of the gorgonian Paramuricea macrospina on the continental shelf and shelf edge (Menorca Channel, Western Mediterranean Sea)

ABSTRACT

Morphological variability in gorgonians is frequent and commonly associated with habitat variability, often resulting in segregated morphotypes. Paramuricea macrospina is an endemic Mediterranean gorgonian species found on rocky bottoms between 40 and 160 m depth and has recently been reported as one of the most abundant species in continental shelf and shelf edge environments. Three different chromatic forms of P. macrospina were observed in the Menorca Channel: a yellow form and a light purple form occurring on maërl beds of the continental shelf, and a dark purple form occurring on rocky substrates of the shelf edge. The objective of the present work is to verify if these P. macrospina forms may represent distinct taxonomic units by analysing differences in colony morphology and sclerite size and shape of the three chromatic forms. No significant differences were found in colony shape, suggesting that environmental variability between the continental shelf and the shelf edge is not influential enough to significantly alter colony morphology. Significant differences in sclerite size and shape were found amongst all forms, suggesting that sclerites may be influenced by environmental conditions. However, the co-occurrence of the yellow and light purple forms side by side on the continental shelf may indicate a certain degree of genetic differentiation.

SUBJECT EDITOR:

• Tina Molodtsova

KEYWORDS:

• Colonial morphology
• gorgonian
• Paramuricea macrospina
• sclerite morphology

Acknowledgements

The authors thank the crew of the RV García del Cid, the JAGO team (Jürgen Schauer and Karen Hissmann) from IFM-GEOMAR (Kiel, Germany) and the NEMO ROV pilot Gavin Newman. We would also like to thank José Manuel Fortuño for his help and advice with the scanning electronic microscope and Guillem Corbera and Stefano Ambroso for their help in some of the laboratory analyses.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Jordi Grinyó http://orcid.org/0000-0001-8425-1349

Additional information

Funding

This work was funded by the European project LIFE+INDEMARES ‘Inventario y designación de la red Natura 2000 en áreas marinas del estado español’ (LIFE07/NAT/E/000732).