Additional description of the Algae Hydroid Thyroscyphus ramosus (Hydrozoa: Leptothecata: Thyroscyphidae) from Palk Bay, India with insights into its ecology and genetic structure

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G. Arun
R. Rajaram
K. Kaleshkumar


The Algae hydroid Thyroscyphus ramosus of the Indian subcontinent is the most easily recognizable fleshy colonial hydroid playing a vital role in benthic communities.  Though this fauna is abundant, it has remained unexplored for the past nine decades in India.  This study provides a detailed report of the morphology, ecology and geographical locations of T. ramosus.  Morphological traits such as maximum height, gonophore, and theca twist directions were studied in detail.  The molecular biological data confirms the identity of T. ramosus and its abundance in Palk Bay, India.  Important molecular markers such as 18S, 16S rRNA sequences of T. ramosus were analyzed and compared with similar species in NCBI.  Using 18S sequence data, it is proven that T. ramosus is a distinct and valid species, however, interestingly the 16S rRNA forms clades with other species of the same genera (T. fruticosus and T. bedoti) rather than the same species.  Moreover the mtCOI forms a different clade with other genera. Furthermore, these data may enhance the advancement of identification in non-monophyletic conditions. 


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G. Arun, R. Rajaram and K. Kaleshkumar 2020. Additional description of the Algae Hydroid Thyroscyphus ramosus (Hydrozoa: Leptothecata: Thyroscyphidae) from Palk Bay, India with insights into its ecology and genetic structure. Journal of Threatened Taxa. 12, 8 (May 2020), 15852–15863. DOI:


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