Over the years as a part of many fishery surveys, considerable number of stomiiform fishes were collected by the Centre for Marine Living Resources and Ecology (CMLRE) Research Vessel ‘Sagar Sampada’. The collection came from throughout the Indian EEZ and some from the western Indian Ocean. However, a systematic identification of these fishes had never been carried out prior to this paper. Thirty-four species were identified and it was found that eight species were new records to India and one to peninsular India. Among the records, two species, Photonectes paxtoni Flynn and Klepadlo, 2012 and Photonectes barnetti Klepadlo, 2011, are collected from the Indian Ocean for the first time. The paper provides a detailed report on all the new records and a list of stomiiform species collected during these surveys. Differences in barbel morphology observed for many of the stomiids are discussed.

Seven species of chirostyloid and galatheoid crustaceans, including three new species, are reported from the eastern Arabian Sea and Bay of Bengal, India, based on material from depths ranging from 32–1420 metres. Trapezionida samudrika sp. nov. appears close to T. munin (Komai, 2011), but is distinguished by the shape of the carapace and fourth thoracic sternite, the armature of the third maxilliped merus, the length and armature of the cheliped, and the armature of the ambulatory legs. Paramunida travancorica sp. nov. differs from its closest species P. bineeshi Macpherson, Chan, Kumar & Rodriguez-Flores, 2020, P. mozambica Cabezas, Macpherson & Machordom, 2010, and P. stichas Macpherson, 1993 in the morphology of the carapace and antennular and antennal peduncles. Munidopsis bhavasagara sp. nov. is similar to M. dentifalx Osawa, Lin & Chan, 2007, but distinguishable by the absence of a pair of elevated, short ridges on the epigastric carapace region and the proportionally shorter chelipeds and ambulatory legs. The present material of Munidopsis unguifera Alcock & Anderson, 1894 represents only the third record of the species in India and a detailed description and illustrations are provided to supplement the previous descriptions. The remaining three species, Eumunida multispina Komai, Chakraborty, Paramasivam & Gidda, 2019, Munidopsis scobina Alcock, 1894, and M. stylirostris Wood-Mason in Wood-Mason & Alcock, 1891, are recorded from additional localities within their known geographic regions.

Details on size at first maturity, embryo number and size, brood chamber volume and reproductive output of deep-sea armoured shrimp, Glyphocrangon investigatoris caught off the south-east coast of India by using EXPO trawl from 633 m depth in FORV ‘Sagar Sampada’ are reported here. Eighty-four female shrimps ranging from 17.29–36.31 mm carapace length and 2.28–16.54 g weight formed 7.73% of total catch, 30% of which was constituted by embryo-bearing females. Regression of weight on carapace length revealed negatively allometric growth (r2 = 0.85, P < 0.01). The size at first maturity was estimated as 19.96 mm. The embryo number ranged from 55 to 233 with a mean of 120.24 ± 34 embryos and showed a positive correlation to body size. Embryo diameter varied between 1.0 to 3.34 mm and more than 50% of embryos constituted the 2.0–2.5 mm size class. Brood chamber volume and percentage frequency of embryo stage development revealed a linear relationship with carapace length. Based on dry weight, mean reproductive output was estimated to be 0.16. The female armoured shrimps showed a high reproductive investment evidenced from few, large, yolky embryos, indicating their deep-sea adaptation.

Frog crabs (Family Raninidae) are cryptic, burying marine brachyuran crabs adapted for inhabiting soft and sandy bottoms across a wide bathymetric range of tropical to low-latitude temperate regions. The present account encompasses re-description of Lysirude channeri from a depth range of 614–655 m in Bay of Bengal, India. Morphological examination of 76 specimens agreed with earlier type descriptions in having two antero-lateral spines, but this contradicts with the specimens from the South China Sea and off the Philippines. In addition, some specimens from the present study revealed the presence of two carpal spines instead of one described before. However, the genetic congruency of the collected specimens were inferred by developing molecular marker viz. mitochondrial cytochrome oxidase subunit I (mtCOI) gene sequences, representing the first molecular data for Lysirude channeri. Phylogram and genetic distance data (up to 0.60%) justified the genetic congruency of Lysirude channeri as well as the interspecific divergence (up to 15.2%) between Lysirude channeri and Lyreidus brevifrons. Hence, the present study provides complete morphological and molecular data for re-describing the frog crab Lysirude channeri and also delineates its speciation from other related brachyuran crabs.

Halieutopsis stellifera was previously reported only from the northern Celebes to the Philippine archipelago and Okinawa Trough. The present study reports Halieutopsis stellifera from the eastern Indian Ocean based on three specimens from Andaman waters (depth range 480 to 580 m).

The occurrence of benthopelagic fish, Neobythites multistriatus, off Mangalore, India, in the Arabian Sea, which is hitherto not recorded from the exclusive economic zone (EEZ) of India, is reported. The results of the comparison of meristic and morphometric characters with the holotype and paratypes of the species are presented. Neobythites multistriatus is closely related to N. fasciatus in terms of two opercular spines and several vertical bars on body ending as ocelli or dark blotches on dorsal and anal fin. However, it differs from the latter by having 11–13 long rakers versus 8–10 and anterior ocellus in front of line versus posterior to line. The occurrence of this little known benthopelagic fish further adds to and strengthens the rich deep sea ichthyofaunal biodiversity of the EEZ of India, which is hitherto not fully known.

This paper reports the first documented record of bathyal fish Glyptophidium oceanium Smith & Radcliffe, 1913 from the Indian Ocean. The species is redescribed and meristics and morphometrics were compared with its holotype. Glyptophidium oceanium is very similar to the closely related species G. japonicum Kamohara, 1936 in terms of the number of pseudobranchial filaments and pectoral fin rays, but differs from the latter in having more developed gill rakers, a larger orbit and a more slender body. The report of this poorly known bathyal fish species helps in unravelling the rich deep-sea ichthyofaunal biodiversity of India, which is still not fully investigated.

Two new species of Munidopsis from the hydrothermal vent area, Kairei Field, Central Indian Ridge in the Indian Ocean and Forecast Vent Field, Mariana Back Arc Basin in the west Pacific are described and illustrated. Their affinities to closely related species are discussed. The number of Munidopsis species associated to hydrothermal vents in the world oceans has increased to 16. The habitat of new species is briefly described and the pattern of abundance of vent associated Munidopsis is briefly discussed.