Deep Sea Eels: Slithering Through the Abyss

Deep sea eels are a diverse assembly of Anguilliformes and related eel-like fishes that inhabit mesopelagic and bathypelagic zones, typically below 200 meters, where they face high hydrostatic pressure, low temperature, and scarce food supply. This article examines the major deep-sea eel families, their morphological adaptations, depth distributions, feeding strategies, and the recent taxonomic discoveries that continue to expand our understanding of these poorly known fishes. The practical utility here is a working list of deep-sea eel species with their reported depth ranges and distinctive features, drawn from peer-reviewed taxonomic and genomic studies published between 2019 and 2025.

Defining the Deep-Sea Eel Assemblage

The term deep-sea eel covers multiple families within the order Anguilliformes, plus several eel-like groups such as cusk eels (Ophidiiformes) and spiny eels (Notacanthiformes) that are not true eels but occupy similar ecological roles. True eels in the deep sea include snipe eels (Nemichthyidae), arrowtooth eels (Synaphobranchidae), duckbill eels (Nettastomatidae), snake eels (Ophichthidae), conger eels (Congridae), and moray eels (Muraenidae). The cusk eels and spiny eels are frequently grouped with deep-sea eels in fisheries records and ecological surveys because they share elongated bodies and benthic or benthopelagic habits.

The environmental constraints of the deep sea are severe. High hydrostatic pressure, low temperature, and scarce food supply are the major factors that limit the survival of vertebrates in extreme deep-sea environments, according to a 2023 genome study of the muddy arrowtooth eel captured below 3,500 meters [3]. These pressures have driven convergent evolution across multiple eel lineages, producing elongated bodies, reduced skeletal ossification, and specialized feeding structures.

Major Deep-Sea Eel Families and Their Depth Ranges

Snipe Eels (Nemichthyidae)

Snipe eels are pelagic fishes with unique specializations for life in the midwater. They exhibit extreme body elongation, reduced skeletal ossification, and highly specialized beak-like jaws that facilitate survival in deep-sea midwater environments [9]. The complete mitochondrial genome of the deep-sea snipe eel Nemichthys curvirostris was sequenced and annotated in 2025, representing the first mitogenomic resource for this species. The circular genome is 16,911 bp in length and contains 37 genes, including 13 protein-coding genes, 22 tRNAs, 2 rRNAs, and a single control region, with an overall A+T bias of 56.67% [9].

Phylogenetic analysis recovered a well-supported monophyletic Nemichthys clade, with N. curvirostris positioned as the sister taxon to N. scolopaceus. The genera Avocettina and Labichthys were recovered as sister taxa, and Nemichthys clustered within a broader clade alongside them [9]. The COX1 haplotype phylogeny showed that two public database sequences appeared as long, isolated branches outside the main N. curvirostris lineage, with COX1 genetic distances from typical haplotypes reaching 12 to 13 percent, far exceeding the expected range of intraspecific variation. This finding highlights the importance of verified genetic reference data for deep-sea species identification [9].

Snipe eels are mesopelagic to bathypelagic, typically encountered between 300 and 2,000 meters. Their beak-like jaws are adapted for capturing crustaceans, particularly shrimps, in the water column.

Arrowtooth Eels (Synaphobranchidae)

The family Synaphobranchidae includes the muddy arrowtooth eel (Ilyophis brunneus), which has become a model for understanding deep-sea genomic adaptation. A high-quality genome was constructed for this species using Illumina, PacBio, and Hi-C sequencing, with the genome estimated at 1.47 Gb and assembled into 14 pseudo-chromosomes [3]. Phylogenetic analyses indicated that I. brunneus diverged from its closely related shallow-sea species, the European eel, approximately 111.9 million years ago and experienced rapid evolution [3].

Genome evolutionary analyses revealed several adaptive changes. Under high hydrostatic pressure, the positively selected gene TUBGCP3 and the expanded family MLC1 may improve cytoskeleton stability. The gene ACOX1 may enhance the fluidity of cell membranes and maintain transport activity, while the expansion of the ABCC12 gene family may enhance the integrity of DNA. Positively selected HARS likely maintains transcription ability at low temperatures, and energy metabolism under a food-limited environment may be increased by expanded and positively selected genes in AMPK and mTOR signaling pathways [3].

A new species in the same subfamily, Ilyophis singularis, was described from the South China Sea in 2022, indicating that the diversity of this family in Asian waters remains incompletely documented [16].

Duckbill Eels (Nettastomatidae)

Nettastomatid eels are characterized by their elongated, pointed snouts. A new species, Facciolella smithi, was described in 2025 based on eight specimens collected from deep water at 260 to 450 meters depth in the eastern Arabian Sea [6]. The new species is characterized by a large head, dorsal-fin origin before the gill openings, bicoloured body and head, and total vertebrae of 156 to 205 or more. It differs from its congeners in the position of the dorsal-fin origin, which is before the gill openings in F. smithi versus behind the gill openings in F. castlei, F. equatorialis, and F. oxyrhynchus. It also differs from F. karrerae and F. saurencheloides in having a larger head, at 43.6 to 47.5 percent of pre-anal length versus 36.2 to 37.3 percent in F. karrerae and 28.5 to 32.0 percent in F. saurencheloides [6]. Comparison with CO1 mtDNA sequences in GenBank and BOLD confirmed that the new species forms a separate genetic lineage [6].

Snake Eels (Ophichthidae)

Snake eels are a large family with many deep-water representatives. Several new species have been described from Indian waters in recent years, reflecting increased deep-sea trawling activity and taxonomic attention.

Xyrias anjaalai was described in 2020 from 12 specimens caught off Kollam, Kerala, southwestern India, by deep-sea trawling [5]. It is distinguished from its congeners by a large eye diameter, a short snout, a distinct dentition pattern in which the third row of maxillary teeth begins at the level of the fourth vomerine tooth, and a vertebral count of 18 to 21 predorsal vertebrae, 73 to 76 preanal vertebrae, and 147 to 149 total vertebrae. Phylogenetic relationships examined using partial nucleotide sequences of the COI gene showed that the new species is closest to X. revulsus followed by Apterichtus klazingai, with Kimura 2 parameter values of 0.6 and 2.8 percent respectively [5].

Ophichthus mccoskeri was described in 2019 based on six specimens of 331 to 447 mm total length trawled at 314 to 363 meters depth in Andaman waters, India [7]. This species is differentiated from its deep-water congeners by a combination of characters including large eyes, dorsal-fin origin a short distance behind the pectoral-fin tip, anal fin black posteriorly, three preopercular pores, maxillary and mandibular teeth ending as triserial, and a vertebral formula of 20/55/153 [7].

Ophichthus nigroventralis was described from the Arabian Sea, southwest coast of India, in 2023 [19]. Apterichtus kanniyakumari, a finless snake eel, was described in 2025 from two specimens collected from deep-sea trawl landings at the Colachel fish landing centre on the southwest coast of India [18]. This species is distinguished by head length of 9.6 to 9.7 percent of total length, tail length of 1.8 to 1.9 percent of total length, body depth at gill openings of 42.1 to 54.8 percent of total length, three preopercular and nine supratemporal pores, conical uniserial teeth on jaws and vomer, distinct golden-yellow body coloration, and three black blotches behind the eyes, in the rictus, and behind the origin of the rictus. The mean vertebral formula is 52 to 131. Molecular analyses based on the mitochondrial CO1 gene show that this new species forms a distinct clade with its sympatric species Apterichtus nanjilnaduensis [18].

Conger Eels (Congridae)

The conger eel family includes both shallow and deep-water species. Macrocephenchelys is a genus of deep-water conger eels, and a new species was described in 2023 from a single specimen collected from a deep-sea trawl landing at Kalamukku fish landing centre, Kerala coast, Arabian Sea [4]. The new species is distinguished by a dorsal-fin origin behind the middle of the pectoral fin, a larger head, shorter trunk, larger gill opening, dark-brown dorsal surface, and ventral surface of head and belly with numerous patches of melanophores before the anus, with vertebrae numbering 14-30-151. It shares most characteristics with Macrocephenchelys brevirostris but differs by having a more anterior dorsal-fin origin, a larger head at 15.3 percent of total length versus 10.5 to 13.9 percent, and a shorter trunk length at 13.6 percent of total length versus 14.4 to 20.6 percent. Genetic divergence from M. brevirostris sequences is 7.9 to 8.1 percent [4].

Congriscus megastoma is another deep-sea conger eel whose complete mitochondrial genome was characterized in 2024, providing phylogenetic insights into the family Congridae [15]. Length-weight relationships for four species of deep-sea conger eels from the southwest coast of India, Arabian Sea, were published in 2023, providing baseline data for fisheries assessments [17].

Moray Eels (Muraenidae)

Moray eels are typically associated with shallow coral reefs, but deep-water species exist. Gymnothorax smithi was described in 2019 based on three specimens collected from the southeastern Arabian Sea, India, at 200 meters depth. This is the first deep-water report of a moray eel from Indian waters [8]. The new species is distinguishable by a greyish-brown body overlain with white spots of irregular shape, dorsal-fin origin anterior to the gill opening, anus positioned slightly behind the mid-point of the body, serrated teeth, and a unique vertebral count of 3 to 5/57/130 to 132 [8].

Cusk Eels (Ophidiidae)

Cusk eels are not true eels but are frequently included in deep-sea eel discussions due to their elongated bodies and similar habitats. Neobythites nanhaiensis was described in 2026 from 14 specimens collected at 400 meters depth near Nan'an Reef in the South China Sea [13]. This species is readily distinguished from all congeners by the unique presence of two, rarely three, distinct black ocelli on the mid-flank, a trait absent in all other Neobythites species. It further lacks stripes, fin ocelli, or dark fin margins. The meristic features include dorsal-fin rays 107, anal-fin rays 93, pectoral-fin rays 25, total vertebrae 62, and 9 to 11 developed gill rakers. The complete mitochondrial genome of 17,287 bp was sequenced, exhibiting the typical vertebrate structure with an A+T bias of 55.1 percent. Phylogenetic analyses based on both the COI gene and the complete mitogenome robustly supported N. nanhaiensis as a distinct monophyletic lineage, sister to N. marginatus [13].

Dicrolene nigricaudis is a rare species of deep-sea cusk eel redescribed from the Indian Exclusive Economic Zone, providing additional morphological data for this poorly known species [21].

Spiny Eels (Notacanthiformes)

Spiny eels are another eel-like group that inhabits deep waters. The snub-nosed spiny eel (Notacanthus chemnitzii) was collected from a depth of 1,000 meters in the northern Atlantic Ocean, and a novel bacterial strain was isolated from its skin [10]. This strain, Planococcus notacanthi sp. nov., is aerobic, cocci, motile, Gram-positive to Gram-variable staining, and gives rise to orange-pigmented colonies. Growth occurs at 4 to 40 degrees Celsius with an optimum of 25 to 28 degrees Celsius, pH 5.5 to 12 with an optimum of pH 7 to 7.5, and 0 to 12 percent NaCl with an optimum of 1 percent [10]. The draft genome sequence is 3.6 Mb with a G+C content of 45.25 mol percent. This strain was previously shown to have antimicrobial activity and to encode bacteriocin and secondary metabolite biosynthetic gene clusters [10].

First transcriptomic data from deep-sea spiny eels of the genus Notacanthus were published in 2025, providing molecular resources for understanding adaptation in this group [22].

At a Glance: Deep-Sea Eel Species Reference Table

Morphological Adaptations to the Deep Sea

Body Elongation and Skeletal Reduction

Extreme body elongation is a recurring theme among deep-sea eels. Snipe eels exhibit extreme body elongation and reduced skeletal ossification, which reduces the energetic cost of maintaining a skeleton in a low-food environment [9]. The elongated body form allows these fishes to pursue prey through the water column and into crevices on the seafloor.

The vertebral counts of deep-sea eels vary widely and serve as important taxonomic characters. For example, Ophichthus mccoskeri has a vertebral formula of 20/55/153, while Xyrias anjaalai has 18 to 21 predorsal, 73 to 76 preanal, and 147 to 149 total vertebrae [5][7]. These counts are stable within species and provide reliable identification characters when combined with other morphological features.

Jaw and Dentition Specializations

Feeding structures show remarkable diversity among deep-sea eels. Snipe eels have highly specialized beak-like jaws that are elongated and curved, allowing them to capture small crustaceans in the midwater [9]. The jaws are delicate and cannot accommodate large prey, reflecting a specialized feeding strategy.

Snake eels show varied dentition patterns that are taxonomically informative. Xyrias anjaalai has a third row of maxillary teeth beginning at the level of the fourth vomerine tooth, positioned between the two existing rows in the inner series of maxillary teeth, with an irregular tooth patch for approximately one-tenth of the lateral side of the dental arch in the distal portion [5]. Ophichthus mccoskeri has maxillary and mandibular teeth ending as triserial [7].

Moray eels possess serrated teeth, as seen in Gymnothorax smithi, which aids in gripping and tearing prey [8]. The combination of tooth morphology and jaw structure reflects the prey types available in each habitat.

Sensory Adaptations

Vision in deep-sea eels is adapted to low-light conditions. A 2025 study of Japanese eels (Anguilla japonica) investigated changes in visual opsin transcript levels during sexual development and exposure to light conditions simulating their life cycle [11]. Tissue-specific expression analysis revealed the predominance of four opsin genes in the eyes: dso, fwo, rh2, and sws2. Immature eels showed increased sws2 expression under blue and green light during the day, with dominant dso, fwo, rh2, and sws2 expression in darkness and green light during the night. Mature eels showed elevated expression levels of dso and rh2 under white light and dark conditions, implicating their broad-spectrum and blue-shifted adaptation to deep-sea migration [11].

Cortisol levels in sexually mature eels were significantly lower under dark conditions, underscoring the ecological significance of low light during reproductive migration [11]. These findings highlight the developmental plasticity of opsin expression and stress responses driven by ecological requirements and life cycle changes.

Feeding Strategies in the Dark

Midwater Foraging

Snipe eels are pelagic foragers that use their specialized jaws to capture crustaceans in the water column. The beak-like jaws are held open as the eel swims forward, snagging prey on the fine teeth. This passive foraging strategy is energy-efficient in an environment where prey is scarce and encounters are unpredictable [9].

Benthic Feeding

Many deep-sea eels are benthic or benthopelagic feeders. Snake eels and conger eels forage on or near the seafloor, using their elongated bodies to enter burrows and crevices in search of crustaceans, polychaetes, and small fishes. The finless snake eel Apterichtus kanniyakumari lacks pectoral fins and has a pointed tail, adaptations for burrowing into soft sediments [18].

Scavenging and Opportunistic Feeding

The muddy arrowtooth eel, captured below 3,500 meters, lives in an environment where food supply is extremely limited. Genome analysis revealed that energy metabolism under a food-limited environment may be increased by expanded and positively selected genes in AMPK and mTOR signaling pathways [3]. These pathways regulate cellular energy homeostasis and may allow the eel to efficiently utilize sporadic food resources.

Practical Assessment Steps for Identifying Deep-Sea Eels

When examining deep-sea eel specimens from trawl catches or research surveys, follow these steps to achieve reliable identification:

1. Record capture depth and location. Depth range is a primary filter for species identification, as many deep-sea eels have restricted depth distributions.

2. Measure total length, pre-anal length, head length, and trunk length. These measurements are used in species descriptions and are essential for comparison with published accounts.

3. Count vertebrae from radiographs or cleared and stained specimens. Vertebral formulas are reported as predorsal, preanal, and total counts, and are diagnostic for many species.

4. Examine dorsal-fin origin relative to gill openings and pectoral-fin position. The position of the dorsal-fin origin is a key character in many families, including Nettastomatidae and Ophichthidae.

5. Document dentition patterns. Note the arrangement of teeth on the jaws and vomer, including the number of rows and any irregular patches.

6. Record colouration and pigmentation patterns. Note the presence of spots, blotches, ocelli, or bicoloured patterns, and the distribution of melanophores on the ventral surface.

7. Collect tissue samples for genetic analysis. The COI gene is the standard barcode marker, and 16S rRNA is also used. Genetic divergence values above 2 percent typically indicate distinct species.

8. Compare morphological and genetic data with published species descriptions and reference sequences in GenBank and BOLD.

Records and Measurements for Research and Fisheries

Accurate records are essential for deep-sea eel research and fisheries management. The following measurements and observations should be recorded for each specimen:

• Capture metadata: date, time, location coordinates, depth, gear type, and vessel
• Morphometric measurements: total length, standard length, pre-anal length, head length, trunk length, tail length, body depth at gill openings, eye diameter, snout length, and gill opening size
• Meristic counts: dorsal-fin rays, anal-fin rays, pectoral-fin rays, vertebrae, and gill rakers
• Colouration notes: body colour, presence of spots or blotches, fin colour, and ventral pigmentation
• Genetic samples: fin clips or muscle tissue preserved in ethanol for DNA extraction
• Photographs: lateral view of the whole specimen, close-up of the head, and details of dentition

Length-weight relationships for deep-sea conger eels from the southwest coast of India were published in 2023, providing baseline data for biomass estimation and fisheries assessments [17]. These relationships allow researchers to convert length measurements to weight estimates without weighing each specimen.

Common Failure Patterns in Deep-Sea Eel Identification

Several recurring problems complicate deep-sea eel identification and should be anticipated:

1. Specimen damage during trawling. Deep-sea trawls often damage specimens, particularly the delicate jaws of snipe eels and the fins of snake eels. Damaged specimens may lack key diagnostic characters.

2. Colouration loss after preservation. Body colour and pigmentation patterns fade in formalin and ethanol, making colour-based characters unreliable in preserved specimens. Document colouration before preservation.

3. Genetic reference gaps. Public databases contain misidentified sequences. The COX1 haplotype phylogeny of Nemichthys curvirostris showed that two public database sequences appeared as long, isolated branches outside the main lineage, with genetic distances of 12 to 13 percent from typical haplotypes [9]. Verify reference sequences before using them for identification.

4. Overlap in morphological characters. Closely related species often overlap in morphometric measurements and meristic counts. Use combinations of characters instead of single features.

5. Incomplete taxonomic coverage. New species continue to be described from deep-sea collections, and existing keys may not include recently described taxa. Consult recent literature before finalizing identifications.

Welfare and Safety Context for Handling Deep-Sea Eels

Deep-sea eels are rarely encountered alive, and most specimens come from trawl catches. When handling live or freshly caught specimens, consider the following:

• Moray eels have sharp, serrated teeth and can inflict serious bites. Use heavy gloves and appropriate handling tools.
• Some deep-sea eels have fragile bodies that tear easily. Support the body when lifting specimens.
• Rapid pressure changes during ascent cause expansion of the swim bladder and other gas-filled spaces, which can damage internal organs. Specimens may appear bloated or damaged.
• Preserve specimens promptly after capture to prevent degradation of genetic material and morphological characters.
• Follow institutional and national regulations regarding collection and export of deep-sea specimens.

Professional Escalation Criteria

Consult a taxonomic specialist or regional fisheries authority when:

1. Specimens cannot be identified using available keys and literature.
2. Morphological characters conflict with genetic data.
3. A specimen may represent an undescribed species or a new record for a region.
4. Genetic sequences show divergence greater than 2 percent from reference sequences in the same nominal species.
5. Specimens are needed for type material or voucher collections in recognized repositories.
6. Deep-sea trawl operations encounter unusual concentrations of eels, which may indicate an ecosystem event requiring management attention.

Frequently Asked Questions

What defines a deep-sea eel?

A deep-sea eel is any eel or eel-like fish that inhabits depths below approximately 200 meters. This includes true eels in the order Anguilliformes, such as snipe eels, arrowtooth eels, duckbill eels, snake eels, conger eels, and moray eels, as well as eel-like groups such as cusk eels (Ophidiiformes) and spiny eels (Notacanthiformes). These fishes share elongated bodies and adaptations to high pressure, low temperature, and scarce food.

How deep do deep-sea eels live?

Depth ranges vary by species. The muddy arrowtooth eel Ilyophis brunneus has been captured below 3,500 meters [3]. Facciolella smithi was collected at 260 to 450 meters [6]. Ophichthus mccoskeri was trawled at 314 to 363 meters [7]. Gymnothorax smithi was reported from 200 meters [8]. Neobythites nanhaiensis was collected at 400 meters [13]. The snub-nosed spiny eel Notacanthus chemnitzii was collected from 1,000 meters [10]. Snipe eels are mesopelagic to bathypelagic, occupying the water column instead of the seafloor [9].

What do deep-sea eels eat?

Deep-sea eels employ diverse feeding strategies. Snipe eels use their beak-like jaws to capture small crustaceans in the midwater [9]. Benthic species such as snake eels and conger eels forage on or near the seafloor for crustaceans, polychaetes, and small fishes. The muddy arrowtooth eel lives in a food-limited environment, and genomic evidence suggests that its energy metabolism is adapted to sporadic food availability through AMPK and mTOR signaling pathways [3].

How do deep-sea eels survive high pressure?

Genomic research on the muddy arrowtooth eel identified several adaptations to high hydrostatic pressure. The positively selected gene TUBGCP3 and the expanded family MLC1 may improve cytoskeleton stability. ACOX1 may enhance cell membrane fluidity and maintain transport activity. The expansion of the ABCC12 gene family may enhance DNA integrity [3]. These adaptations help maintain cellular function under extreme pressure.

Are new deep-sea eel species still being discovered?

Yes. Multiple new species have been described in recent years, including Facciolella smithi in 2025 [6], Apterichtus kanniyakumari in 2025 [18], Neobythites nanhaiensis in 2026 [13], Ophichthus nigroventralis in 2023 [19], Macrocephenchelys sp. nov. in 2023 [4], Ilyophis singularis in 2022 [16], Xyrias anjaalai in 2020 [5], Ophichthus mccoskeri in 2019 [7], and Gymnothorax smithi in 2019 [8]. These discoveries indicate that deep-sea eel diversity remains incompletely documented.

How are deep-sea eel species identified?

Identification combines morphological and genetic methods. Morphological characters include body measurements, vertebral counts, fin positions, dentition patterns, and colouration. Genetic identification typically uses the COI barcode gene and 16S rRNA. For example, Xyrias anjaalai was identified using morphological analysis of 12 specimens and molecular analysis of four specimens, with genetic analyses showing it is closest to X. revulsus with a Kimura 2 parameter value of 0.6 percent [5]. Genetic divergence values above 2 percent typically indicate distinct species.

Why are mitochondrial genomes important for deep-sea eel research?

Mitochondrial genomes provide valuable molecular resources for phylogenetic, evolutionary, and population genetic studies. The complete mitogenome of Nemichthys curvirostris was the first for this species and helped resolve its phylogenetic position as the sister taxon to N. scolopaceus [9]. The mitogenome of Neobythites nanhaiensis supported its status as a distinct monophyletic lineage sister to N. marginatus [13]. The mitogenome of Congriscus megastoma provided phylogenetic insights into the Congridae [15].

What is the relationship between deep-sea eels and shallow-water eels?

The muddy arrow

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References and Further Reading

• NCBI Literature Resources. National Center for Biotechnology Information.
• PubMed. National Library of Medicine.
• Pseudo-chromosome-length genome assembly for a deep-sea eel Ilyophis brunneus sheds light on the deep-sea adaptation.. Science China. Life sciences, 2023.
• A new species of the conger eel genus Macrocephenchelys from deep waters of the Arabian Sea.. Journal of fish biology, 2023.
• A new deep-water species of snake eel, Xyrias anjaalai sp. nov. (Anguilliformes: Ophichthidae), from the Western Indian Ocean.. Zootaxa, 2020.
• Facciolella smithi, a new species of deep-water nettastomatid eel (Anguilliformes: Nettastomatidae) from the Arabian Sea.. Zootaxa, 2025.
• Description of a new species of deep-water snake eel, Ophichthus mccoskeri (Ophichthidae: Ophichthinae) from Andaman Sea, India.. Zootaxa, 2019.
• A new species of white-spotted moray eel, Gymnothorax smithi (Muraenidae: Muraeninae) from deep waters of Arabian Sea, India.. Zootaxa, 2019.
• The Complete Mitochondrial Genome of Deep-Sea Snipe Eel Nemichthys curvirostris (Anguilliformes: Nemichthyidae).. Genes, 2025.
• Planococcus notacanthi sp. nov., isolated from the skin of a deep-sea snub-nosed spiny eel.. International journal of systematic and evolutionary microbiology, 2024.
• Analysis of visual opsin gene expression in Japanese eels upon sexual maturation and exposure to different wavelengths of light.. 2025.
• Isolation, Characterization, and Evaluation of a Lytic Jumbo Phage Z90 Against Aeromonas hydrophila in American Eels (Anguilla rostrata).. 2025.
• &lt,i&gt,Neobythites nanhaiensis&lt,/i&gt, sp. nov. (Ophidiidae, Ophidiiformes) from the South China Sea, with morphology, mitogenome, and its phylogenetic position.. 2026.
• Convergent morphological and genetic patterns delimit Evolutionary Significant Units in endangered Aipysurus sea snakes.. 2025.
• First insights into the complete mitochondrial genome of a deep-sea eel Congriscus megastoma (Anguilliformes, Congroidei, Congridae): characterization and phylogenetic inference. Biologia, 2024.
• Ilyophis singularis (Synaphobranchidae, Ilyophinae), a new deep-sea eel from the South China Sea. Ichthyological Research, 2022.
• Length-Weight Relationship of Four Species of Deep-Sea Congrid Eel (Congridae) from the Southwest Coast of India, Arabian Sea. Journal of Ichthyology : A Translation of Voprosy Ikhtiologii, 2023.
• Apterichtus kanniyakumari, a new species of finless snake eel (Anguilliformes: Ophichthidae) from the Arabian Sea.. Zootaxa, 2025.
• A new species of deep-water snake eel, Ophichthus nigroventralis (Anguilliformes: Ophichthidae) from the Arabian Sea, southwest coast of India. Ichthyological Research, 2023.
• New records of two deep-sea eels collected from the Western Pacific Ocean based on COI and 16S rRNA genes. Molecular Biology Reports, 2021.
• Redescription of dicrolene nigricaudis (alcock, 1899) a rare species of deep sea cusk eel (ophidiiformes, ophidiidae) from Indian EEZ. Indian Journal of Marine Sciences, 2009.
• A “light in the darkness”: First transcriptomic data from deep-sea spiny eels (Notacanthus, Notacanthiformes). Marine Genomics, 2025.

This article is educational and does not replace institutional policy, professional advice, or applicable safety and regulatory requirements.