Sea Snake Research Articles

Viviparous sea snakes can be used as bioindicators for diverse marine environments

Shallow tropical marine ecosystems are under great anthropogenic pressure due to habitat destruction, overfishing, shrimping, climate change, and tourism. This is an issue of global concern as such environments hold a tremendous biodiversity much of which remains to be described. The present situation urgently calls for time- and resource-efficient methods to identify and delineate the most valuable remaining areas and to set up priorities for their management and conservation. Using indicator species can be a way to accomplish this goal. In this paper we evaluate whether viviparous sea snakes can serve as bioindicators for other rare or cryptic tropical marine fauna. Based on seven generally acknowledged criteria for bioindicators, we argue that using viviparous sea snakes as bioindicators can help monitoring marine habitats to gauge the effects of climate change, habitat change and loss, decline in biodiversity and other anthropogenic changes. However, to maximize their efficacy as bioindicators, deeper knowledge about viviparous sea snakes natural history is urgently needed. Topics for expanded research programs include the taxonomy of some groups, their breeding and feeding biology, habitat selection and their geographical distribution. Despite these gaps in our understanding, we argue that viviparous sea snakes can be utilized as bioindicators of marine ecosystem health. KEYWORDS: anthropogenic changes, conservation, herpetology, marine habitat, monitoring

Oxygen isotopes from the teeth of Cretaceous marine lizards reveal their migration and consumption of freshwater in the Western Interior Seaway, North America

Mosasaurs were widespread predators of the vast Cretaceous seas, and it is debated whether these extinct marine reptiles migrated to coastal environments to feed or reproduce. Here we investigate the potential for migration of mosasaurs through novel high-resolution sclerochronology that samples incremental growth lines in fossil mosasaur teeth and extracts oxygen isotopes from pristine enamel. Oxygen isotope trends of consecutive teeth are spliced to reconstruct one to seven month-long life histories of Platecarpus tympaniticus and Clidastes propython mosasaurs, respectively, collected from time-equivalent chalk deposits of the Western Interior Seaway and Mississippi Embayment of North America. The records of all individuals—two adults and one juvenile—are characterized by semi-regular depletions in oxygen isotope values, indicating travel from marine to freshwater coastal environments. Weekly to bi-weekly consumption of freshwater by two genera at diverse life stages implies that mosasaur osmoregulatory function was similar to their living sea snake relatives that drink freshwater periodically.

Captive culture of two sea snake species <i>Hydrophis curtus</i> and <i>Hydrophis cyanocinctus</i>

Acclimation culture and trial culture of two sea snake species Hydrophis curtus and H. cyanocinctus in composite tanks were conducted to determine growth, survival rate, predation behavior and prey selection. The results showed that adults of H. curtus and H. cyanocinctus did not capture any prey such as anchovy, eel and shrimp in a period of 30 days of acclimation culture. The body weight of two these species reduced gradually from 783.3 ± 76.4 g and 360.0 ± 60.0 g to 660.0 ± 135.2 g and 315.0 ± 77.8 g, respectively. Survival rate was 100% in H. curtus and 80% in H. cyanocinctus. Meanwhile, the results of acclimation culture of sea snake juvenile revealed that frozen anchovy was preferred prey in both of two species. The body weight of H. curtus increased from 49.8 ± 0.5 g to 70.0 ± 8.2 g and that of H. cyanocinctus was 44.3 ± 3.1 g to 47.1 ± 5.2 g. The prey capture rate of H. curtus and H. cyanocinctus was 100% and 60%, respectively. Survival rate of the juvenile of two species was 100% after 30 days of acclimation culture. In 60 days of trial culture, similar results as acclimation culture were observed in adults of two sea snake species, they still did not capture any prey and the body weight reduced gradually. The result of 60-day culture of sea snake juvenile showed that the prey capture rate was 100% in both of two species. The body weight of H. curtus and H. cyanocinctus increased from 70.0 ± 8.2 g and 57.5 ± 5.8 g to 78.3 ± 15.3 g and 65.0 ± 14.1, respectively. SGR of H. curtus was 0.16 ± 0.32 %/day and that of H. cyanocinctus was 0.52 ± 0.36%/day. The survival rate of H. curtus and H. cyanocinctus was 60% and 40% in period of 60 day trial.

Fast floating temperature sensor measures SST, not wet bulb temperature

AbstractA small integrated oceanographic thermometer with a nominal response time of 1 s was affixed to a floating hose “sea snake” towed near the bow of a research vessel. The sensor measured the near-surface ocean temperature accurately and in agreement with other platforms. The effect of conduction and evaporation is modeled for a sensor impulsively alternated between water and air. Large thermal mass makes most sea snake thermometers insensitive to temperature impulses. The smaller 1-s thermometer cooled by evaporation, but the sensor never reached the wet bulb temperature. The cooling was less than 6% of the (~2.7 °C) difference between the ocean temperature and the wet bulb temperature in 99% of 2 s–1 samples. Filtering outliers, such as with a median, effectively removes the evaporative cooling effect from 1- or 10-minute average temperatures.

Identification of Chinese medicine sea snake based on cytochrome B (Cytb)

The identification of species primordium has been one of the hot issues in the identification of traditional Chinese medicine. Sea snake is one of the most valuable Chinese medicinal materials in China. In order to understand the origin and varieties of sea snake in the market, we studied the molecular identification of 46 sea snakes by cytochrome B(Cytb). After comparison and manual correction, the sequence length was 582 bp, and the content of A+T(58.9%) was higher than that of G+C(41.1%). There exist 197 variable sites and 179 parsimony-informative sites of the sequence. There are 44 kinds of sequence alignment with consistency equal to 100%, and 2 kinds equal to 96%. A total of 408 Cytb effective sequences were downloaded from GenBank database, with a total of 68 species. Phylogenetic tree of a total of 454 sea snake sequences with the samples in this study were constructed by neighbor-joining trees and Bayesian inference method, respectively, which can identify 42 samples of medicinal materials, while 4 samples can not be identified because of their low node support. The results showed that the species of the sea snake medicine were at least from 2 genera and 5 species, namely, Aipysurus eydouxii, Hydrophis curtus, H. caerulescen, H. curtus, H. ornatus and H. spiralis. This study suggested that the original species of commercial sea snake are very complex and can provide insight into the identification of sea snakes.

Thirst and drinking in North American watersnakes (Nerodia spp.).

ABSTRACTWe quantified drinking behavior in three species of North American watersnakes: Nerodia clarkii, which is a marine or brackish water amphibious species, and Nerodia fasciata and Nerodia taxispilota, both freshwater amphibious species. All three species have relatively small and similar thresholds of dehydration (TH, approximately −4% loss of body mass) that elicit thirst and drinking of fresh water. These species have higher thirst sensitivity than several species of hydrophiine and laticaudine sea snakes, which are characterized by much lower TH (greater dehydration, −9% to <−20%). Nerodia clarkii, which is often found in coastal oceanic water, refused to drink seawater, but drank fresh water when dehydrated. In separate trials involving dehydration of N. clarkii and N. fasciata that were concurrently fed fish at regular intervals, snakes eventually refused to eat at TH of approximately −12% of original body mass, but resumed eating after they were allowed to drink fresh water and rehydrate. The drinking behaviors of Nerodia corroborate previous data on the importance of fresh water for drinking, and they complement growing evidence that dietary water does not itself mitigate dehydration in snakes. These new data increase understanding of water relationships in the context of evolutionary transitions from land to sea, and they emphasize the importance of fresh water resources in the conservation of coastal and marine species of reptiles.

Peaceful coexistence between people and deadly wildlife: Why are recreational users of the ocean so rarely bitten by sea snakes?

Abstract Research on interactions between humans and deadly snakes has focused on situations that result in high rates of snakebite; but we can also learn from cases where snakes and people coexist peacefully. For example, coastal bays near Noumea, in the Pacific archipelago of New Caledonia, are used by thousands of tourists and snakes, but bites are rare. Our long‐term studies clarify reasons for this coexistence. Although 97% of snakes encountered in standardised snorkel surveys were a harmless species Emydocephalus annulatus, we recorded dangerously venomous taxa often enough (one snake per 8 hr snorkelling) that we would expect many risky human–snake interactions in these crowded bays. However, the risk is reduced by low overlap between humans and snakes in the timing of activity, both seasonally and on the diel cycle. Mate‐searching male snakes, the group most likely to approach divers, enter the bays only in cooler months of the year when few beach users are present. Also, snakes tend to be active by night, whereas people are not. Risk is further reduced by spatial divergence: bare‐footed beach users stay in sandy areas rather than the adjacent coral‐reef areas that are preferred by snakes. The response of snakes to disturbance is also important: most sea snakes are reluctant to bite even when harassed. Water currents frequently push sea snakes against hard objects, perhaps explaining why the snakes do not interpret brief contact with a human as an attack. The ability of snakes to flee is increased by uniformly high body temperature, and a complex three‐dimensional aquatic environment. Thus, the danger of snakebite for recreational users of these popular beaches is reduced by aspects of human and snake behaviour that (a) decrease encounter rates and (b) render snakes unlikely to bite even if contacted. The risk to snakes is also reduced because snakes are more difficult to detect and kill underwater than on land. As a result, thousands of snakes and people coexist harmoniously within these small bays.

De Novo Venom-Gland Transcriptomics of Spine-Bellied Sea Snake (Hydrophis curtus) from Penang, Malaysia-Next-Generation Sequencing, Functional Annotation and Toxinological Correlation.

Envenomation resulted from sea snake bite is a highly lethal health hazard in Southeast Asia. Although commonly caused by sea snakes of Hydrophiinae, each species is evolutionarily distinct and thus, unveiling the toxin gene diversity within individual species is important. Applying next-generation sequencing, this study investigated the venom-gland transcriptome of Hydrophis curtus (spine-bellied sea snake) from Penang, West Malaysia. The transcriptome was de novo assembled, followed by gene annotation and sequence analyses. Transcripts with toxin annotation were only 96 in number but highly expressed, constituting 48.18% of total FPKM in the overall transcriptome. Of the 21 toxin families, three-finger toxins (3FTX) were the most abundantly expressed and functionally diverse, followed by phospholipases A2. Lh_FTX001 (short neurotoxin) and Lh_FTX013 (long neurotoxin) were the most dominant 3FTXs expressed, consistent with the pathophysiology of envenomation. Lh_FTX001 and Lh_FTX013 were variable in amino acid compositions and predicted epitopes, while Lh_FTX001 showed high sequence similarity with the short neurotoxin from Hydrophis schistosus, supporting cross-neutralization effect of Sea Snake Antivenom. Other toxins of low gene expression, for example, snake venom metalloproteinases and L-amino acid oxidases not commonly studied in sea snake venom were also identified, enriching the knowledgebase of sea snake toxins for future study.

Nagumoea hydrophicola sp. nov. (Bacillariophyta), the first diatom species described from sea snakes

Although diatoms colonize a vast diversity of immersed hard-surfaced objects and organisms, many diatom species, and sometimes entire genera, show a clear preference towards a particular type of substratum. Studies of animal-associated diatoms indicate that some epizoic forms may require this specific habitat to thrive, and new diatom taxa are expected to be found on as yet unexplored animal hosts. The current study is the first to investigate the diatom flora of sea snakes. Three museum specimens of yellow-bellied sea snakes (Hydrophis platurus) collected over a period of 23 years from the south-eastern coast of South Africa were examined for their diatom flora. Diatoms were abundant on the sea snakes, but communities were composed of only a few species. A previously undescribed species of Nagumoea contributed over 99% of the total diatom assemblage on both the sea snake skin and sea-snake-associated barnacles (Octolasmis sp.). This diatom dominant is described here as Nagumoea hydrophicola sp. nov., based on detailed observations of its frustule ultrastructure using light and scanning electron microscopy. The species is most similar to N. serrata, sharing a similar valvocopula morphology with two rows of pores. However, it can be distinguished from all currently known congeners by its lanceolate central area, short distal raphe endings not reaching the valve mantle, and doubly perforated abvalvar girdle bands. Environmental preferences of the new species are discussed in the context of its host’s biology.

Olfaction of aquatic amniotes

Amniotes originated on land, but aquatic/amphibious groups emerged multiple times independently in amniotes. On becoming aquatic, species with different phylogenetic backgrounds and body plans have to adapt themselves to handle similar problems inflicted by their new environment, and this makes aquatic adaptation of amniotes one of the greatest natural experiments. Particularly, evolution of the sense of smell upon aquatic adaptation is of great interest because receptors required for underwater olfaction differ remarkably from those for terrestrial olfaction. Here, I review the olfactory capabilities of aquatic/amphibious amniotes, especially those of cetaceans and sea snakes. Most aquatic/amphibious amniotes show reduced olfactory organs, receptor gene repertoires, and olfactory capabilities. Remarkably, cetaceans and sea snakes show extreme examples: cetaceans have lost the vomeronasal system, and furthermore, toothed whales have lost all of their olfactory nervous systems. Baleen whales can smell in the air, but their olfactory capability is limited. Fully aquatic sea snakes have lost the main olfactory system but they retain the vomeronasal system for sensing underwater. Amphibious species show an intermediate status between terrestrial and aquatic species, implying their importance on understanding the process of aquatic adaptation. The olfactory capabilities of aquatic amniotes are diverse, reflecting their diverse phylogenetic backgrounds and ecology.

Development of a 16S metabarcoding assay for the environmental DNA (eDNA) detection of aquatic reptiles across northern Australia

A severe lack of distribution data for aquatic reptiles in northern Australia leaves many taxa vulnerable to extirpation and extinction. Environmental DNA (eDNA) technologies offer sensitive and non-invasive genetic alternatives to trapping and visual surveys and are increasingly employed for the detection of aquatic and semi-aquatic reptiles. However, these eDNA approaches have largely applied species-specific primers that do not provide a cost-effective avenue for the simultaneous detection of multiple reptilian taxa. Here, we present a mitochondrial 16S rRNA metabarcoding assay for the broad detection of aquatic and semi-aquatic reptile species. This assay is tested on water samples collected at multiple sampling sites at two tropical locations, including 12 marine and estuarine sites in Roebuck Bay, Western Australia, and four estuarine sites in Cooktown, Queensland, Australia. In total, nine reptile taxa were detected from 10 of the 16 sampled sites, including marine and freshwater turtles, aquatic, semi-aquatic and terrestrial snakes, and terrestrial skinks. However, inconsistencies in the detection of previously observed aquatic reptiles at our sampled sites, such as saltwater crocodile and sea snakes, indicated that further research is required to assess the reliability, strengths and limitations of eDNA methods for aquatic reptile detection before it can be integrated as a broad-scale bioassessment tool.

Порівняльна характеристика макрофауни обростання літоконтуру Одеського морського регіону і острова Зміїного Чорного моря

The data on composition and indices of quantitative development of invertebrates’ macrofauna in the foulingof lithocontour of natural origin in the coastal zone of Odessa sea region (OSR) and Snake Island in 2005–2014 arepresented. A total of 71 taxa were registered: 57 – in OSR and 38 – near island. In OSR the average density of macrofaunawas 34,263 ind.∙m-2, biomass – 14,067.5 g∙m-2; near island – 102,842 ind.∙m-2 and 16,552.6 g∙m-2. Among taxonomicgroups molluscs were quantitatively dominant in OSR (74.0%) and crustaceans near island (65.3%); while molluscsformed most of biomass at both sites (97.6% and 98.1% respectively). The bulk of fauna biomass (94.4% in OSR,93.6% near island) was formed by Mytilus galloprovincialis. Among the trophic groups sestonophages dominatedon quantity (83.2%) and biomass (98.5%) in OSR; whereas near island phyto-detrithophages dominated on quantity(56.2%) and sestonophages on biomass (98.8%). The average biomass of food component for fish was two times highernear island than in OSR and its basis (69.5–85.4%) was formed by molluscs. Seven invasive species were found in OSRand two near Snake Island. The basis of their quantity and biomass was formed by Amphibalanus improvisus.The state of lithocontour fouling of macrofauna belonging to Mytilus galloprovincialis biocenosis could becharacterized as stable and satisfactory.

Demographic analyses of marine and terrestrial snakes (Elapidae) using whole genome sequences.

The question of whether spatial aspects of evolution differ in marine versus terrestrial realms has endured since Ernst Mayr's 1954 essay on marine speciation. Marine systems are often suggested to support larger and more highly connected populations, but quantitative comparisons with terrestrial systems have been lacking. Here, we compared the population histories of marine and terrestrial elapid snakes using the pairwise sequentially Markovian coalescent (PSMC) model to track historical fluctuations in species' effective population sizes (Ne ) from individual whole-genome sequences. To do this we generated a draft genome for the olive sea snake (Aiysurus laevis) and analysed this alongside six published elapid genomes and their sequence reads (marine species Hydrophis curtus, H.melanocephalus and Laticauda laticaudata; terrestrial species Pseudonaja textilis, Naja Naja and Notechis scutatus). Counter to the expectation that marine species should show higher overall Ne and less pronounced fluctuations in Ne , our analyses reveal demographic patterns that are highly variable among species and do not clearly correspond to major ecological divisions. At deeper time intervals, the four marine elapids appear to have experienced relatively stable Ne , while each terrestrial species shows a prominent upturn in Ne starting at ~4 million years ago (Ma) followed by an equally strong decline. However, over the last million years, all seven species show strong and divergent fluctuations. Estimates of Ne in the most recent intervals (~10kya) are lowest in two of four marine species (H.melanocephalus and Laticauda), and do not correspond to contemporary range sizes in marine or terrestrial taxa.

Retraction Note to: Biological and Biochemical Potential of Sea Snake Venom and Characterization of Phospholipase A2 and Anticoagulation Activity.

[This retracts the article DOI: 10.1007/s12291-015-0500-6.].

Streptococcus iniae associated mass marine fish kill off Western Australia.

Streptococcus iniae causes high mortality in cultured and wild fish stocks globally. Since the first report in captive Amazon river dolphins Inia geoffrensis in 1976, it has emerged in finfish across all continents except Antarctica. In March 2016, an estimated 17000 fish were observed dead and dying along a remote 70 km stretch of the Kimberley coastline north of Broome, Western Australia. Affected species included finfish (lionfish Pterois volitans, angelfish Pomacanthus sp., stripey snapper Lutjanus carponotatus, sand bass Psammoperca waigiensis, yellowtail grunter Amniataba caudavittata, damselfish Pomacentridae sp.), flatback sea turtles Natator depressus, and olive (Aipysurus laevis) and black-ringed (Hydrelaps darwiniensis) sea snakes. Moribund fish collected during the event exhibited exophthalmia and abnormal behaviour, such as spiralling on the surface or within the water column. Subsequent histopathological examination of 2 fish species revealed bacterial septicaemia with chains of Gram-positive cocci seen in multiple organs and within brain tissue. S. iniae was isolated and identified by bacterial culture, species-specific PCR, Matrix-Assisted Laser Desorption Ionisation Time-Of-Flight (MALDI-TOF) and biochemical testing. This is the first report of S. iniae associated with a major multi-species wild marine fish kill in Australia. Extreme weather events in the region including a marked decrease in water temperatures, followed by an extended period of above-average coastal water temperatures, were implicated as stressors potentially contributing to this outbreak.

Visual adaptation of opsin genes to the aquatic environment in sea snakes

BackgroundEvolutionary transitions from terrestrial to aquatic life history cause drastic changes in sensory systems. Indeed, the drastic changes in vision have been reported in many aquatic amniotes, convergently. Recently, the opsin genes of the full-aquatic sea snakes have been reported. However, those of the amphibious sea snakes have not been examined in detail.ResultsHere, we investigated opsin genes and visual pigments of sea snakes. We determined the sequences of SWS1, LWS, and RH1 genes from one terrestrial, three amphibious and four fully-aquatic elapids. Amino acid replacements at four and one spectra-tuning positions were found in LWS and RH1, respectively. We measured or predicted absorption of LWS and RH1 pigments with A1-derived retinal. During their evolution, blue shifts of LWS pigments have occurred stepwise in amphibious sea snakes and convergently in both amphibious and fully-aquatic species.ConclusionsBlue shifted LWS pigments may have adapted to deep water or open water environments dominated by blue light. The evolution of opsins differs between marine mammals (cetaceans and pinnipeds) and sea snakes in two fundamental ways: (1) pseudogenization of opsins in marine mammals; and (2) large blue shifts of LWS pigments in sea snakes. It may be possible to explain these two differences at the level of photoreceptor cell composition given that cone and rod cells both exist in mammals whereas only cone cells exist in fully-aquatic sea snakes. We hypothesize that the differences in photoreceptor cell compositions may have differentially affected the evolution of opsins in divergent amniote lineages.

Antipredator tactics: a kin‐selection benefit for defensive spines in coral catfish?

Morphological features that impair a predator's ability to consume a prey item may benefit individual prey; but what of features that prolong prey‐handling but do not enhance prey survival? For example, a striped eel catfish Plotosus lineatus will be fatally envenomated if struck by its specialist predator, the greater sea snake Hydrophis major. Nonetheless, the catfish typically erects long, toxic pectoral and dorsal spines that increase prey‐handling times for the snake by around eightfold. Because the catfish travel in swarms of closely‐related individuals, the delay enforced by spines may enable the victim's swarm‐mates to disperse before the snake is able to search for another meal. In keeping with that hypothesis, defensive spines tend to be longer in catfish from regions where the greater sea snake occurs, than from areas where the snake does not occur.

Population history and genomic admixture of sea snakes of the genus Laticauda in the West Pacific

Speciation in the open ocean has long been studied, but it remains largely elusive what factors promote or inhibit speciation in such an open environment. Marine amniotes, which evolved from terrestrial ancestors, provide valuable opportunities for studying speciation in the ocean because of their evident aquatic origins. Sea snakes are phylogenetically related to terrestrial elapid snakes and consist of two monophyletic groups (Hydrophiini and Laticaudini). These two groups migrated from land to water almost at the same time, but species diversities are remarkably different: there are approx. 60 species in 16 genera described for hydrophiins, whereas only eight species in the genus Laticauda are described for laticaudins. Here, we provide a high-quality reference genome assembly of a laticaudin L. colubrina with a scaffold N50 value of 40 Mbp, and focused on laticaudins to consider why they have seldom speciated. We performed whole-genome shotgun sequencing of several species of laticaudins sampled in their southmost (Vanuatu) and northmost (Ryukyu) habitats. Demographic histories of Vanuatu and Ryukyu populations suggest that populations of broadly distributed major species are geographically structured. Each species is genetically clearly distinguished, but there is a considerable amount of gene flow between two sibling species distributed sympatrically in Vanuatu. In addition, inter-species genomic admixture is ubiquitously observed among laticaudins even between phylogenetically distant species. Broad distribution of major species combined with such genetic mixability might have prevented laticaudins from genetic isolation and speciation.

Establishing the ecological basis for conservation of shallow marine life using Reef Life Survey

Reef Life Survey (RLS) provides a new model for ecological monitoring through training experienced recreational divers in underwater visual census methods to the level of skilled scientists. Detail produced is similar to that of programs with professional scientific teams, at low cost to allow global coverage. RLS differs from most other citizen science initiatives in its emphasis on rigorous training and data quality rather than open participation, selectively involving the most skilled and committed members. Volunteers participate primarily because they appreciate the close relationship with scientists, other divers, and managers, and see their efforts directly contributing to improved environmental outcomes. RLS works closely with Australian management agencies, scheduling annual events at core monitoring sites associated with 10 inshore marine protected areas Australia-wide. Surveys of 12 offshore Australian Marine Parks (AMPs) are realized through 2–4 week voyages in a sailing catamaran crewed by volunteers. Across the AMP network, RLS surveys have quantified densities of fishes, mobile invertebrates, macroalgae and corals at 350 shallow coral reef sites (180 sites surveyed on two or more occasions), providing an understanding of (i) population changes amongst threatened species including sea snakes, (ii) responses of fish and invertebrate populations following fisheries closures, (iii) ecosystem-wide impacts of marine heat-waves, and (iv) the extent that AMPs spanning the network comprehensively encompass national coral reef biodiversity. This scientist/volunteer/manager collaboration could be greatly expanded globally (presently 3537 sites in 53 countries).

New Environment, New Invaders-Repeated Horizontal Transfer of LINEs to Sea Snakes.

Although numerous studies have found horizontal transposon transfer (HTT) to be widespread across metazoans, few have focused on HTT in marine ecosystems. To investigate potential recent HTTs into marine species, we searched for novel repetitive elements in sea snakes, a group of elapids which transitioned to a marine habitat at most 18 Ma. Our analysis uncovered repeated HTTs into sea snakes following their marine transition. The seven subfamilies of horizontally transferred LINE retrotransposons we identified in the olive sea snake (Aipysurus laevis) are transcribed, and hence are likely still active and expanding across the genome. A search of 600 metazoan genomes found all seven were absent from other amniotes, including terrestrial elapids, with the most similar LINEs present in fish and marine invertebrates. The one exception was a similar LINE found in sea kraits, a lineage of amphibious elapids which independently transitioned to a marine environment 25 Ma. Our finding of repeated horizontal transfer events into marine snakes greatly expands past findings that the marine environment promotes the transfer of transposons. Transposons are drivers of evolution as sources of genomic sequence and hence genomic novelty. We identified 13 candidate genes for HTT-induced adaptive change based on internal or neighboring HTT LINE insertions. One of these, ADCY4, is of particular interest as a part of the KEGG adaptation pathway “Circadian Entrainment.” This provides evidence of the ecological interactions between species influencing evolution of metazoans not only through specific selection pressures, but also by contributing novel genomic material.