A new deep-water coral species Telestula ridgensis sp. nov (Scleralcyonacea: Sarcodictyonidae) from the seamount of the Central Indian Ridge.

Telestula ridgensis sp. nov. is a deep-sea octocoral species collected from the Central Indian Ridges (CIR) seamount. The megabenthic communities were sampled from the depths between 1917 and 2053 m using a benthic sledge. It forms part of a baseline environmental and benthic ecological assessment. All these data will be functional in assessing the impact of future massive sulfide mining in the Indian Ocean. We describe a new octocoral species based on integrative taxonomic methods through morphological comparison and molecular phylogenetics. The sclerome of the new species consists of short, stellate plates, crosses, and irregularly shaped and branching forms with dense tubercular ornamentation. The polyp sclerites are arranged in longitudinal rows underneath the tentacles. Two mitochondrial DNA genes (mtMutS and COI) and one ribosomal nuclear DNA gene (28S rRNA) were sequenced to separate the new species. The phylogenetic analyses strongly support the placement of new species in the genus Telestula clade.

Two new deep-water species of squat lobsters (Crustacea: Anomura: Galatheoidea) from the Central and Southwest Indian Ridge.

The high diversity and endemism of benthic species on seamounts are extensively documented. Although the number of squat lobster species from seamount habitats has increased, species from the Central Indian Ridge (CIR) and Southwest Indian Ridge (SWIR) systems remain largely unknown. The hydrothermally active Indian Ridge system harbours potential sites for future Seafloor Massive Sulphides (SMS) mining. Since seabed mining may create a long-lasting impact on the deep-sea ecosystems, it could harm the unique deep-sea life associated with mineral deposits. This study identified two undescribed squat lobster specimens: one from the genus Munidopsis Whiteaves, 1874 from the CIR system in water depths ranging from 1981 to 2033 m, and one from the genus Typhlonida Macpherson & Baba in Machordom, Ahyong, Andreakis, Baba, Buckley, Garcia-Jimenez, McCallum, Rodriguez-Flores & Macpherson, 2022 from the SWIR system in depths ranging from 2070 to 2404 m. Both new species may be distinguished morphologically and genetically based on the partial mitochondrial (mtCOI) gene. To generate baseline environmental and biodiversity data, efforts for accurate sampling and correct identification of biological species are required.

Is the North Atlantic Geodia barretti (Porifera, Tetractinellida, Geodiidae) present on the Southwest Indian Ridge?

There are currently 163 species of Geodia Lamarck, 1815 described worldwide, many of which are found in deep waters, but none of which have been recorded from the Southwest Indian Ridge (SWIR). Spicule morphology and barcodes (Folmer COI, 28S (C2D2), partial 18S) suggest that a specimen of Geodia collected on the SWIR at a depth of 2236 m is closely comparable to Geodia barretti Bowerbank, 1858. Geodia barretti is the most studied and thus well-known deep-sea Geodia species, due to its wide North Atlantic distribution and key role in boreal sponge grounds. This unexpected and markedly disjunct record would extend the distribution range of this species considerably, consequently challenging our knowledge about interoceanic deep-sea sponges.

Coral reef-associated brachyuran fauna (Crustacea: Decapoda: Brachyura) from Angria Bank off the west coast of India.

Underwater sampling via SCUBA and grab at the Angria Bank coral reefs off the central west coast of India in January 2014 revealed 11 species of Brachyura. Seven species, namely, Thusaenys irami (Laurie, 1906), Tanaocheles bidentata (Nobili, 1901), Portunus convexus De Haan, 1835, Xiphonectes macrophthalmus (Rathbun, 1906), Thalamita gatavakensis Nobili, 1906, Serenius ceylonicus (Laurie, 1906), and Soliella flava (Rathbun, 1894) are reported for the first time from Indian waters. Furthermore, the geographical distribution of T. irami and S. ceylonicus is extended westwards of hitherto known ranges.

Complete mitochondrial genome of the Spadenose shark Scoliodon laticaudus (Carcharhiniformes: Carcharhinidae).

The complete mitochondrial genome of the Spadenose shark Scoliodon laticaudus has been determined for the first time in this study. It was 16,695 bp in length and consisted of 37 genes with typical gene order in vertebrate mitogenome. The nucleotide base content of S. laticaudus mitogenome was 31.5% A, 23.7% C, 13.2% G and 31.6% T. Two start codons (GTG and ATG) and three stop codons (AGA, TAG and TAA/T) were used in the protein-coding genes. The 22 tRNAs ranged from 67 bp (tRNA-Cys and tRNA-Ser2) to 75 bp (tRNA-Leu1) in length. The tRNA-Ser2 could not be folded into typical cloverleaf secondary structure by lacking the dihydrouridine (DHC) arm stem.