To see the other types of publications on this topic, follow the link: Sea snakes.
Journal articles on the topic 'Sea snakes'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Sea snakes.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Lillywhite, Harvey B., Coleman M. Sheehy, François Brischoux, and Alana Grech. "Pelagic sea snakes dehydrate at sea." Proceedings of the Royal Society B: Biological Sciences 281, no. 1782 (May 7, 2014): 20140119. http://dx.doi.org/10.1098/rspb.2014.0119.
Full textAbstract:
Secondarily marine vertebrates are thought to live independently of fresh water. Here, we demonstrate a paradigm shift for the widely distributed pelagic sea snake, Hydrophis ( Pelamis ) platurus , which dehydrates at sea and spends a significant part of its life in a dehydrated state corresponding to seasonal drought. Snakes that are captured following prolonged periods without rainfall have lower body water content, lower body condition and increased tendencies to drink fresh water than do snakes that are captured following seasonal periods of high rainfall. These animals do not drink seawater and must rehydrate by drinking from a freshwater lens that forms on the ocean surface during heavy precipitation. The new data based on field studies indicate unequivocally that this marine vertebrate dehydrates at sea where individuals may live in a dehydrated state for possibly six to seven months at a time. This information provides new insights for understanding water requirements of sea snakes, reasons for recent declines and extinctions of sea snakes and more accurate prediction for how changing patterns of precipitation might affect these and other secondarily marine vertebrates living in tropical oceans.
2
Wassenberg, TJ, JP Salini, H. Heatwole, and JD Kerr. "Incidental capture of sea-snakes (Hydrophiidae) by prawn trawlers in the Gulf of Carpentaria, Australia." Marine and Freshwater Research 45, no. 3 (1994): 429. http://dx.doi.org/10.1071/mf9940429.
Full textAbstract:
Sea-snakes were collected from research trawlers and commercial prawn trawlers in the Gulf of Carpentaria during the period from April 1976 to December 1991. The data were analysed on the basis of CPUE (catch per unit effort) for depth, latitude and season. The research trawlers, operating in the eastern Gulf of Carpentaria, and the commercial prawn trawlers, operating in the south-western Gulf of Carpentaria, caught sea-snakes at a rate of 0.028 and 0.026 sea-snakes per metre of headrope length per hour, respectively. Lapemis hardwickii was the sea-snake most commonly caught by the research trawlers-53% of all snakes-and Hydrophis elegans was the sea-snake most commonly caught by commercial trawlers-25% of all snakes. Depth was the most significant factor affecting CPUE, with more than 70% of all sea-snakes being caught in waters less than 15 m deep. When catches of all species were combined, a significant interaction (P<0.05) existed between depth and season. L. hardwickii specimens were caught more frequently in shallow coastal waters (< 15 m deep) in spring but in deeper water further offshore in autumn. A significant interaction between latitude and depth was found for Astrotia stokesii; specimens were caught more frequently in deeper water at 14% Enhydrina schistosa is generally coastal, with 8800 of specimens being caught in water less than 10 m deep. Seasonal movement of sea-snakes between inshore and offshore waters may be linked to their breeding cycles. The estimated number of sea-snakes captured in the Gulf of Carpentaria for the 1991 prawning season ranged from 73 583 to 165 559, with a mean of 119 571. The survival rate of sea-snakes from commercial prawn trawls was about 60% and hence between 29 801 and 67 051 sea-snakes are estimated to have died.
3
Ayunda Pratiska, I. Gusti Putu, Ida Bagus Made Suaskara, Joko Wiryatno, and I. Gede Agus Pradana Putra. "INVENTARISASI JENIS – JENIS ULAR YANG DITEMUKAN DI SEKITAR PANTAI MERTA SARI DAN PADANG GALAK." SIMBIOSIS Journal of Biological Sciences 5, no. 2 (September 30, 2017): 69. http://dx.doi.org/10.24843/jsimbiosis.2017.v05.i02.p07.
Full textAbstract:
Sea snakes have a strong venom and when they bite can be fatal for humans, whereas snakes found in mangrove areas are weak venomous snakes and non-venomous snakes (McKay, 2006). The low understanding public aboutthe snakes has led to the assumption that any snakes found are dangerous, so research needs to be done in order to provide information on the types of venomous and non-venomous snakes present in coastal areas and around mangrove forest areas. This research was conducted from early January to the end of January located around Merta Sari Beach to Padang Galak. The method used is the method of cruising method is done by determining the habitat that is likely suitable for snake habitat (Asad et al., 2011). Data collected in the morning and at night, by capturing and identifying snakes found in situ refers to the snake identification titled '107+ Ular Indonesia' (Riza Marlon, 2014), and the book 'Reptiles and Amphibians in Bali 'By Mckay (2006). Based on the results of the study, snakes found around Merta Sari Beach and Padang Galak Beach numbered 61 individual snakes with two different families namely Colubridae and Elapidae. Snake species of the Colubridae family found are Dog-faced Water Snake (Cerberus rynchops) and the Elapidae family is the Erabu/Yellow-lipped Sea Krait (Laticauda colubrina) snake
4
Kabir, Ashraful. "Biography of a snake charmer in Saidpur, Bangladesh." MOJ Biology and Medicine 3, no. 4 (2018): 151–52. http://dx.doi.org/10.15406/mojbm.2018.03.00090.
Full textAbstract:
Though Saidpur Upazila under Nilphamari district is very small but here pigeonry, goat rearing, herbal treatments, circus team, monkey charmer, horse race and snake charmers are available. Snake charmers are not living well in this modern era. Their kids are not safe at home for snake rearing. In Savar, Dhaka there is a snake market where some tribal people buy it as food. People who are engaged with snake catching and snake-based superstitions go to that market. They support medical science and are waiting to get a good job. Who take snakes as food they say its meat is very hot. Depending on body size its price varies from 1000 to 2000 taka of a poisonous snake. People of the circus team, zoo committee and intersex people collects snakes from the snake charmer. Tradition of snake charming in Bangladesh is very ancient. Once upon a time most of the villagers liked it. Some peoples were considered as bede or tribal people who caught snakes from the jungle. Though Bangladesh is a small country but its 80 species of snakes are remarkable. Within these only cobras, kraits and sea snakes are poisonous and most of the cobras are bicellate type. Common vine snakes, tree snake and rat snakes are very common and nonpoisonous snakes of Bangladesh. After catching a snake, the charmer cuts the poison sac or rubs both fangs of the snakes. As poison of the snakes are digestive juice so that those snakes can suffer digestive ailments and ultimately die. The temperature of Rangpur division of Bangladesh is 350-370F which is suitable for snakes’ survival. There were 30.77% poisonous and 69.23% non poisonous snakes’ in Bangladesh in three families.1 In Bangladesh out of 82 species 28 are venomous and 12 are sea snakes.2 Estimates indicate ˃5 million bites annually by venomous snakes worldwide where ˃12500 deaths.3,4 Some research work have completed on snakes taxonomy, status, distribution and epidemiology of snake bite.5‒7 India has the highest number of snake bites in the world with 35000-50000 annually according to World Health Organization.8,9 In Bangladesh this is 4.3per 100000 an annual incidence and case fatality is 20%.10
5
Gillett, Amber K., Richard Ploeg, Mark Flint, and Paul C. Mills. "Postmortem examination of Australian sea snakes (Hydrophiinae): Anatomy and common pathologic conditions." Journal of Veterinary Diagnostic Investigation 29, no. 5 (May 26, 2017): 593–611. http://dx.doi.org/10.1177/1040638717710056.
Full textAbstract:
There is limited published information about disease in wild sea snakes and no standardized guideline for postmortem examination of sea snakes. Identifying causes of morbidity and mortality of marine vertebrate species has been pivotal to understanding disease factors implicated in stranding events and assisting with the formulation of conservation plans. Additionally, postmortem findings can provide valuable information on life history traits and the ecology of these reclusive species. Sick, moribund, or dead sea snakes are intermittently washed ashore along Australian and international beaches and provide an opportunity to examine a subset of the population and identify causes of population decline. We present an illustrated description of sea snake anatomy and describe a systematic approach to postmortem examination of sea snakes. We describe common pathologic conditions identified from clinical and postmortem examinations of stranded Australian sea snakes from southeast Queensland. Notable pathologic conditions include traumatic injury, inflammatory conditions, parasitic infections, and neoplasia.
6
Milton, David A., Gary C. Fry, and Quinton Dell. "Reducing impacts of trawling on protected sea snakes: by-catch reduction devices improve escapement and survival." Marine and Freshwater Research 60, no. 8 (2009): 824. http://dx.doi.org/10.1071/mf08221.
Full textAbstract:
Sea snakes (Hydrophidae) are by-catch of prawn trawling throughout the tropical Indo-western Pacific. We tested the effectiveness of three by-catch reduction device (BRD) types set at different distances from the codend in Australia’s Northern Prawn Fishery (NPF). Trained crew-member observers compared the numbers of sea snakes caught in paired Control and Treatment nets in 1365 trawls. Catches of sea snakes were reduced by 43% on those vessels where a Fisheye BRD was positioned less than 70 meshes from the codend. A separate study with a scientific observer undertook trials with a ‘popeye’ Fishbox BRD. This BRD reduced sea snake catch by 85% and small fish by-catch by 48%. Catches of target prawn were similar for all nets in both studies (difference <2%). Adoption of the more effective BRDs (‘popeye’ Fishbox or Fisheye BRDs) by the NPF and locating them within 70 meshes of the codend can potentially reduce sea snake catch and thus their mortality from ~7000 in the 2007 fishing season to as few as 1500 snakes. Our study shows that the use of BRDs in tropical coastal demersal fisheries and positioning them closer to the codend will greatly reduce the catch of vulnerable sea snakes.
7
C. Fry, G., D. A. Milton, and T. J. Wassenberg. "The reproductive biology and diet of sea snake bycatch of prawn trawling in northern Australia: characteristics important for assessing the impacts on populations." Pacific Conservation Biology 7, no. 1 (2001): 55. http://dx.doi.org/10.1071/pc010055.
Full textAbstract:
Trawlers catch up to 17 species of sea snake as bycatch in the Northern Prawn Fishery (NPF) in northern Australia. We examined the biological characteristics of 660 sea snakes caught by research, scientific observer and commercial vessels between 1986 and 1998 as part of a project to assess their vulnerability. Three species accounted for more than 75% of the total sea snakes caught. Hydrophis species were more common in unstructured habitats close to prawn trawling grounds, while Aipysurus species were the dominant species in areas having reef structure. Sea snakes were caught more frequently at night on commercial trawlers and even more were caught during the day by research trawling. Female sea snakes were caught more often than males for 10 out of 13 species examined. The proportion of mature sea snakes in trawl catches was high (67% males, 89% females). Juvenile sea snakes of most species are not caught suggesting there is little impact of trawling on recruits. We found all species breed annually, producing a few large young after a gestation period of 6-7 months. Litter size varied between 1 to 20 and young of most species were born during the NPF closed season (Nov-Mar). Except for Aipysurus duboisii, Disteira major and Hydrophis ornatus, pregnant females of most species were not more catchable by prawn trawls than non-pregnant females. The relative clutch mass had little effect on the catchability of pregnant females. Most sea snake species had a specialized diet, feeding on one to four benthic fish species and did not appear to be attracted into trawl grounds by the increased availability of discarded bycatch. Their reproductive characteristics mean that populations of many species caught by trawlers in northern Australia are potentially vulnerable.
8
Xiaokaiti, Xiakena, Yasuyuki Hashiguchi, Hidetoshi Ota, and Yoshinori Kumazawa. "Evolution of the Noncoding Features of Sea Snake Mitochondrial Genomes within Elapidae." Genes 13, no. 8 (August 17, 2022): 1470. http://dx.doi.org/10.3390/genes13081470.
Full textAbstract:
Mitochondrial genomes of four elapid snakes (three marine species [Emydocephalus ijimae, Hydrophis ornatus, and Hydrophis melanocephalus], and one terrestrial species [Sinomicrurus japonicus]) were completely sequenced by a combination of Sanger sequencing, next-generation sequencing and Nanopore sequencing. Nanopore sequencing was especially effective in accurately reading through long tandem repeats in these genomes. This led us to show that major noncoding regions in the mitochondrial genomes of those three sea snakes contain considerably long tandem duplications, unlike the mitochondrial genomes previously reported for same and other sea snake species. We also found a transposition of the light-strand replication origin within a tRNA gene cluster for the three sea snakes. This change can be explained by the Tandem Duplication—Random Loss model, which was further supported by remnant intervening sequences between tRNA genes. Mitochondrial genomes of true snakes (Alethinophidia) have been shown to contain duplicate major noncoding regions, each of which includes the control region necessary for regulating the heavy-strand replication and transcription from both strands. However, the control region completely disappeared from one of the two major noncoding regions for two Hydrophis sea snakes, posing evolutionary questions on the roles of duplicate control regions in snake mitochondrial genomes. The timing and molecular mechanisms for these changes are discussed based on the elapid phylogeny.
9
Voris, Harold K., and Harold Heatwole. "Sea Snakes." Copeia 1988, no. 1 (February 5, 1988): 270. http://dx.doi.org/10.2307/1445956.
Full text
10
Dunson, William A. "Sea Snakes." Copeia 2000, no. 4 (December 2000): 1136–37. http://dx.doi.org/10.1643/0045-8511(2000)000[1136:br]2.0.co;2.
Full text
11
Sherratt, Emma, Arne R. Rasmussen, and Kate L. Sanders. "Trophic specialization drives morphological evolution in sea snakes." Royal Society Open Science 5, no. 3 (March 2018): 172141. http://dx.doi.org/10.1098/rsos.172141.
Full textAbstract:
Viviparous sea snakes are the most rapidly speciating reptiles known, yet the ecological factors underlying this radiation are poorly understood. Here, we reconstructed dated trees for 75% of sea snake species and quantified body shape (forebody relative to hindbody girth), maximum body length and trophic diversity to examine how dietary specialization has influenced morphological diversification in this rapid radiation. We show that sea snake body shape and size are strongly correlated with the proportion of burrowing prey in the diet. Specialist predators of burrowing eels have convergently evolved a ‘microcephalic’ morphotype with dramatically reduced forebody relative to hindbody girth and intermediate body length. By comparison, snakes that predominantly feed on burrowing gobies are generally short-bodied and small-headed, but there is no evidence of convergent evolution. The eel specialists also exhibit faster rates of size and shape evolution compared to all other sea snakes, including those that feed on gobies. Our results suggest that trophic specialization to particular burrowing prey (eels) has invoked strong selective pressures that manifest as predictable and rapid morphological changes. Further studies are needed to examine the genetic and developmental mechanisms underlying these dramatic morphological changes and assess their role in sea snake speciation.
12
Burns, Glen, and Harold Heatwole. "Growth, sexual dimorphism, and population biology of the olive sea snake, Aipysurus laevis, on the Great Barrier Reef of Australia." Amphibia-Reptilia 21, no. 3 (2000): 289–300. http://dx.doi.org/10.1163/156853800507480.
Full textAbstract:
AbstractThe olive sea snake, Aipysurus laevis (Lacépède) grows at a rate of 0.22-0.95 cm/month, with young animals growing faster than older ones. Males reach sexual maturity in their third year and females in their fourth or fifth year. There is sexual dimorphism in size, with females larger than males; at snout-vent lengths greater than 80 cm, females are heavier than males of equivalent length. Small snakes were uncommon. Apparent sexratio favours males in winter but moves toward equality or even a preponderance of females in summer, probably reflecting changes in reproductive behaviour. Numbers of snakes are approximately 0.70-0.86 snakes per metre of reef edge. Olive sea snakes live to about 15 years or older.
13
RASMUSSEN, ARNE REDSTED, JOHAN ELMBERG, PETER GRAVLUND, and IVAN INEICH. "Sea snakes (Serpentes: subfamilies Hydrophiinae and Laticaudinae) in Vietnam: a comprehensive checklist and an updated identification key." Zootaxa 2894, no. 1 (May 27, 2011): 1. http://dx.doi.org/10.11646/zootaxa.2894.1.1.
Full textAbstract:
Sea snakes (Elapidae, subfamilies Hydrophiinae and Laticaudinae) reach a very high species richness in Southeast Asia, but most countries in the region still lack comprehensive and up-to-date identification tools for these snakes. We present an updated checklist of sea snakes in Vietnam. We also provide diagnostic characters for all species and a new complete identification key, chiefly based on easy-to-use external characters. The checklist and key cover the 25 species documented from Vietnam, as well as three likely future additions to its sea snake fauna. By surveying incoming fishing vessels between Nha Trang and the mouth of Mekong River in 2000–2001, we were able to document two species new for Vietnamese waters: Hydrophis belcheri and H. pachycercos. Through these surveys we also secured four specimens of the rare endemic species H. parviceps, formerly known only from two specimens. A comprehensive bibliography of the literature treating sea snakes in Vietnamese waters is provided.Identification key: bibliography, biodiversity, diagnostic characters, Vietnamese waters
14
Matsumoto, Kazumasa, and Akira Mori. "Adaptive foraging strategy of an insular snake (Lycodon semicarinatus, Colubridae) feeding on patchily distributed nests of sea turtles." Behaviour 158, no. 10 (June 2, 2021): 869–99. http://dx.doi.org/10.1163/1568539x-bja10099.
Full textAbstract:
Abstract Foraging tactics of predators generally include two major modes, active searching and ambushing. A colubrid snake, Lycodon semicarinatus, is a typical example of a predator, which uses both tactics to forage on sea turtles on islands of the Kerama Group in the Central Ryukyu Archipelago, Japan. To investigate factors that determine the foraging mode of this snake, we conducted a four-year field survey on its foraging behaviour on sea turtles on another island, Okinawa Island. We found that the snake performs only active searching at our study site. Snakes visited a small area exactly above the nest of sea turtles and attempted to burrow a tunnel to feed on eggs and hatchlings in the sand. Tunnels leading from the surface of the beach to the inside of the nest were formed only by large snakes. Many other snakes used the already made tunnels to capture eggs and hatchlings in the nest. When the snakes caught a hatchling, they brought the hatchling away into the nearby bush area without swallowing it above the nest (taking-away behaviour). When snakes failed to find food on a nest, they terminated the intensive search above the nest in approximately 5 minutes irrespective of snake body size, season, and the condition of the nest. Subsequently, they left the nest and resumed extensive searching for other nests. Our findings showed that L. semicarinatus has a different foraging strategy depending on populations. Two environmental traits, diversity of available prey animals other than sea turtles and characteristics of sand that beaches consist of, were considered as factors that might cause the difference in the foraging strategy. The fine sand of our study site enables snakes to form a sturdy tunnel in nests. We presume that such an environment facilitates the use of active searching by the snakes to find the nest with tunnels suitable for exploitation. The taking-away behaviour may be effective to reduce excessive contact with other conspecifics under the situation that the nest with tunnels attracts many visitors. Furthermore, the observation that the snake left the nest site after a consistent duration of unprofitable searching supports the giving-up time rule, which has been predicted by a theoretical model concerning the optimal time for predators to leave a patch.
15
GRAHAM, JEFFREY B., WILLIAM R. LOWELL, IRA RUBINOFF, and JORGE MOTTA. "Surface and Subsurface Swimming of the Sea Snake Pelamis Platurus." Journal of Experimental Biology 127, no. 1 (January 1, 1987): 27–44. http://dx.doi.org/10.1242/jeb.127.1.27.
Full textAbstract:
During anguilliform swimming at the surface, four half waves are present along the body of the yellow-bellied sea snake Pelamis platurus (Hydrophiidae). As in other anguilliform swimmers, wave amplitude increases towards the tail; however, the relative caudal amplitude of P. platurus is less than that of the aquatic snakes Natrix and Nerodia and the eel Anguilla. Kinematic analyses of near-surface swimming at 15 and 32cms−1 were made from high-speed ciné films, and Lighthill's bulk momentum hydromechanical model was used to calculate swimming thrust power at these two velocities. The total thrust power generated by a 51 cm snake is 3–641×10−4 Js−1 at 15cms−1 and 29.877×10−4 Js−1 at 32cms−1, with respective Froude efficiencies of 79% and 81%. Subsurface swimming velocities are low (2–4cms−1), and snakes usually assume a posture in which the tail is elevated and the posterior part of the body assumes a nearly vertical orientation. Undulatory movements by snakes swimming in this posture involve torsional and rolling motions of the body which, through changes in the camber of the keel and body, may contribute to thrust.
16
Crowe-Riddell, Jenna M., Edward P. Snelling, Amy P. Watson, Anton Kyuseop Suh, Julian C. Partridge, and Kate L. Sanders. "The evolution of scale sensilla in the transition from land to sea in elapid snakes." Open Biology 6, no. 6 (June 2016): 160054. http://dx.doi.org/10.1098/rsob.160054.
Full textAbstract:
Scale sensilla are small tactile mechanosensory organs located on the head scales of many squamate reptiles (lizards and snakes). In sea snakes and sea kraits (Elapidae: Hydrophiinae), these scale organs are presumptive scale sensilla that purportedly function as both tactile mechanoreceptors and potentially as hydrodynamic receptors capable of sensing the displacement of water. We combined scanning electron microscopy, silicone casting of the skin and quadrate sampling with a phylogenetic analysis to assess morphological variation in sensilla on the postocular head scale(s) across four terrestrial, 13 fully aquatic and two semi-aquatic species of elapids. Substantial variation exists in the overall coverage of sensilla (0.8–6.5%) among the species sampled and is broadly overlapping in aquatic and terrestrial lineages. However, two observations suggest a divergent, possibly hydrodynamic sensory role of sensilla in sea snake and sea krait species. First, scale sensilla are more protruding (dome-shaped) in aquatic species than in their terrestrial counterparts. Second, exceptionally high overall coverage of sensilla is found only in the fully aquatic sea snakes, and this attribute appears to have evolved multiple times within this group. Our quantification of coverage as a proxy for relative ‘sensitivity’ represents the first analysis of the evolution of sensilla in the transition from terrestrial to marine habitats. However, evidence from physiological and behavioural studies is needed to confirm the functional role of scale sensilla in sea snakes and sea kraits.
17
Takasaki, C., and N. Tamiya. "Isolation and amino acid sequence of a short-chain neurotoxin from an Australian elapid snake, Pseudechis australis." Biochemical Journal 232, no. 2 (December 1, 1985): 367–71. http://dx.doi.org/10.1042/bj2320367.
Full textAbstract:
A short-chain neurotoxin Pseudechis australis a (toxin Pa a) was isolated from the venom of an Australian elapid snake Pseudechis australis (king brown snake) by sequential chromatography on CM-cellulose, Sephadex G-50 and CM-cellulose columns. Toxin Pa a has an LD50 (intravenous) value of 76 micrograms/kg body wt. in mice and consists of 62 amino acid residues. The amino acid sequence of Pa a shows considerable homology with those of short-chain neurotoxins of elapid snakes, especially of true sea snakes.
18
Brischoux, François, Cédric Cotté, Harvey B. Lillywhite, Frédéric Bailleul, Maxime Lalire, and Philippe Gaspar. "Oceanic circulation models help to predict global biogeography of pelagic yellow-bellied sea snake." Biology Letters 12, no. 8 (August 2016): 20160436. http://dx.doi.org/10.1098/rsbl.2016.0436.
Full textAbstract:
It is well recognized that most marine vertebrates, and especially tetrapods, precisely orient and actively move in apparently homogeneous oceanic environments. Here, we investigate the presumptive role of oceanic currents in biogeographic patterns observed in a secondarily marine tetrapod, the yellow-bellied sea snake ( Hydrophis [ Pelamis ] platurus ). State-of-the-art world ocean circulation models show how H. platurus , the only pelagic species of sea snake, can potentially exploit oceanic currents to disperse and maintain population mixing between localities that spread over two-thirds of the Earth's circumference. The very close association of these snakes with surface currents seems to provide a highly efficient dispersal mechanism that allowed this species to range extensively and relatively quickly well beyond the central Indo-Pacific area, the centre of origin, abundance and diversity of sea snakes. Our results further suggest that the pan-oceanic population of this species must be extraordinarily large.
19
Bonnet, Xavier, Sophie Lorioux, François Brischoux, and Margot De Crignis. "Is melanism adaptive in sea kraits?" Amphibia-Reptilia 29, no. 1 (2008): 1–5. http://dx.doi.org/10.1163/156853808783431523.
Full textAbstract:
Abstract Ontogenic melanism (progressive darkening of the skin) has been documented in snakes. Black coloration of the skin often compromises the cryptic effects associated with other patterns (e.g. zigzags) and exposes individuals to predation; however, the mortality risk can be balanced, for example by a thermoregulatory advantage during sun basking. Such adaptive context has been proposed to explain the appearance and the maintenance of melanism within snake populations. Based on a very large captures and re-captures sample (>8000 observations) gathered on two species of sea-kraits (Laticauda saintgironsi and L. laticaudata in New Caledonia), we observed that melanism occurred in only one species (L. laticaudata), was infrequent and concerned adult snakes solely. None of three adaptive hypotheses respectively linked to thermoregulation, predation, or protection against sun radiations, provided a satisfactory account for the occurrence of melanism in our study populations. Therefore, we suggest that melanism was a fortuitous phenomenon.
20
Keogh, J. Scott. "Sea Snakes. Harold Heatwole." Quarterly Review of Biology 75, no. 3 (September 2000): 327. http://dx.doi.org/10.1086/393548.
Full text
21
Ward, T. M. "Factors affecting the catch rates and relative abundance of sea snakes in the by-catch of trawlers targeting tiger and endeavour prawns on the northern Australian continental shelf." Marine and Freshwater Research 51, no. 2 (2000): 155. http://dx.doi.org/10.1071/mf98134.
Full textAbstract:
A total of 4378 sea snakes (14 species; 5 unidentified specimens) were collected from 21 082 h of sampling effort by trawlers of the Northern Prawn Fishery. Most species (12) were collected from the southern Gulf of Carpentaria. Hydrophis elegans and Disteira major were caught frequently in all areas. The catch rates of H. elegans and Lapemis hardwickii were highest in the eastern gulf and in depths of 31–40 and <20 m respectively. Hydrophis elegans represented >27% of specimens from most areas. Other species that represented ≥20% of specimens from one or more areas were: L. hardwickii, H. ornatus, D. major and Aipysurus eydouxii. Catch rates of all species of snakes combined did not differ significantly between 1984–86 and 1989–90, and were moderately high around Groote Eylandt where the fishery is centred. Most by-catch species occur in areas that are not subjected to extensive trawling, and there are no data to suggest that this fishery seriously threatens any population of sea snake. However, sea snakes may be more vulnerable to trawler-induced effects than most other by-catch species, and formal assessment of the status of populations is needed.
22
Dudgeon, Christine L., and William T. White. "First record of potential Batesian mimicry in an elasmobranch: juvenile zebra sharks mimic banded sea snakes?" Marine and Freshwater Research 63, no. 6 (2012): 545. http://dx.doi.org/10.1071/mf11211.
Full textAbstract:
Various forms of mimicry have been recorded in a large number of marine fishes; however, there have been no records of mimicry for any elasmobranch species. We propose that the distinctly banded neonates of the zebra shark (Stegostoma fasciatum) are Batesian mimics of banded sea snakes (Elapidae). Observations of banded juveniles of S. fasciatum swimming close to the surface strongly resemble banded sea snakes in colour and body form as well as the undulatory swimming movements. Sea snakes are venomous and are known to defend themselves against predators. Although several shark species prey on them, most species appear to avoid sea snakes as prey items. Juvenile S. fasciatum possess a very long, single-lobed caudal fin that remarkably resembles the broad, paddle-like tail of sea snakes. This may be an adaptation enabling this species to mimic sea snakes, at least in the earliest life stages. There is a need for empirical testing of the hypothesis that juvenile S. fasciatum is a true example of Batesian mimicry, but here we provide evidence that suggests this may be the first example of mimicry in an elasmobranch species.
23
Voris, Harold K., and William B. Jeffries. "Predation on marine snakes: a case for decapods supported by new observations from Thailand." Journal of Tropical Ecology 11, no. 4 (November 1995): 569–76. http://dx.doi.org/10.1017/s0266467400009147.
Full textAbstract:
ABSTRACTScientific and commercial collecting have documented high levels of abundance among several species of marine snakes. Estimates of first-year mortality in populations of marine snakes range from 40 to 90%. The primary cause of this mortality is unknown. Storms, currents, sun exposure, dehydration and fire are abiotic factors that may control populations of marine and amphibious snakes. Disease, malnutrition and predation are biotic factors known to affect populations. In the literature there are isolated reports of predation by marine mammals, birds of prey, fish and invertebrates. Sharks in Australian waters are known to be predators on sea snakes. Our studies show that in the estuaries, intertidal mangrove creeks and mud flats of southeast Asia decapod crustaceans are important snake predators. Microhabitat overlap, exoskeleton armour and a respiratory advantage in an underwater standoff argue for their potential as potent predators. Field observations, a survey of crab stomach contents and encounters between snakes and crabs under laboratory conditions support this hypothesis. –
24
Crowe-Riddell, Jenna M., Ruth Williams, Lucille Chapuis, and Kate L. Sanders. "Ultrastructural evidence of a mechanosensory function of scale organs (sensilla) in sea snakes (Hydrophiinae)." Royal Society Open Science 6, no. 4 (April 2019): 182022. http://dx.doi.org/10.1098/rsos.182022.
Full textAbstract:
The evolution of epidermal scales was a major innovation in lepidosaurs, providing a barrier to dehydration and physical stress, while functioning as a sensitive interface for detecting mechanical stimuli in the environment. In snakes, mechanoreception involves tiny scale organs (sensilla) that are concentrated on the surface of the head. The fully marine sea snakes (Hydrophiinae) are closely related to terrestrial hydrophiine snakes but have substantially more protruding (dome-shaped) scale organs that often cover a larger portion of the scale surface. Various divergent selection pressures in the marine environment could account for this morphological variation relating to detection of mechanical stimuli from direct contact with stimuli and/or indirect contact via water motion (i.e. ‘hydrodynamic reception’), or co-option for alternate sensory or non-sensory functions. We addressed these hypotheses using immunohistochemistry, and light and electron microscopy, to describe the cells and nerve connections underlying scale organs in two sea snakes, Aipysurus laevis and Hydrophis stokesii . Our results show ultrastructural features in the cephalic scale organs of both marine species that closely resemble the mechanosensitive Meissner-like corpuscles that underlie terrestrial snake scale organs. We conclude that the scale organs of marine hydrophiines have retained a mechanosensory function, but future studies are needed to examine whether they are sensitive to hydrodynamic stimuli.
25
Kishida, Takushi, Yasuhiro Go, Shoji Tatsumoto, Kaori Tatsumi, Shigehiro Kuraku, and Mamoru Toda. "Loss of olfaction in sea snakes provides new perspectives on the aquatic adaptation of amniotes." Proceedings of the Royal Society B: Biological Sciences 286, no. 1910 (September 11, 2019): 20191828. http://dx.doi.org/10.1098/rspb.2019.1828.
Full textAbstract:
Marine amniotes, a polyphyletic group, provide an excellent opportunity for studying convergent evolution. Their sense of smell tends to degenerate, but this process has not been explored by comparing fully aquatic species with their amphibious relatives in an evolutionary context. Here, we sequenced the genomes of fully aquatic and amphibious sea snakes and identified repertoires of chemosensory receptor genes involved in olfaction. Snakes possess large numbers of the olfactory receptor ( OR ) genes and the type-2 vomeronasal receptor ( V2R ) genes, and expression profiling in the olfactory tissues suggests that snakes use the ORs in the main olfactory system (MOS) and the V2Rs in the vomeronasal system (VNS). The number of OR genes has decreased in sea snakes, and fully aquatic species lost MOS which is responsible for detecting airborne odours. By contrast, sea snakes including fully aquatic species retain a number of V2R genes and a well-developed VNS for smelling underwater. This study suggests that the sense of smell also degenerated in sea snakes, particularly in fully aquatic species, but their residual olfactory capability is distinct from that of other fully aquatic amniotes. Amphibious species show an intermediate status between terrestrial and fully aquatic snakes, implying their importance in understanding the process of aquatic adaptation.
26
Shier, W. Thomas, and Anthony T. Tu. "Sea Snakes and Their Venoms." Toxin Reviews 30, no. 4 (November 2011): 122–23. http://dx.doi.org/10.3109/15569543.2011.633240.
Full text
27
Liu, Y. L., H. B. Lillywhite, and M. C. Tu. "Sea snakes anticipate tropical cyclone." Marine Biology 157, no. 11 (July 3, 2010): 2369–73. http://dx.doi.org/10.1007/s00227-010-1501-x.
Full text
28
De-Weerdt, Joëlle, Carla Patulny, and Phillip Clapham. "The yellow-bellied sea snake, Hydrophis platurus (Squamata: Elapidae), off the Southwestern Pacific coast of Nicaragua, Central America." Revista de Biología Tropical 69, Suppl.2 (September 6, 2021): S297—S303. http://dx.doi.org/10.15517/rbt.v69isuppl.2.48324.
Full textAbstract:
Introduction: The yellow-bellied sea snake (Hydrophis platurus, formerly Pelamis platurus) is known to occur along the Pacific coast of Central America. However, there are no marine records of this species off the coast of Nicaragua.
Objective: Report the first in situ marine observations of the yellow-bellied sea snake observed on three occasions in 2020 during cetacean surveys off the southwestern Pacific coast of Nicaragua.
Methods: During the sightings, photographs were taken which allowed the identification of the species based on morphology. Sea surface temperature, sea state, and distance to the coast are presented as descriptors of the habitat of the records.
Results: Three field observations of yellow-bellied sea snakes were recorded on separate occasions. Sightings occurred within 30 km of each other and 3.3 km from the coast. Average sea surface temperature was 26.6 °C with low swell and sea state.
Conclusions: The present information offers new knowledge about the presence of the yellow-bellied sea snake on the Pacific coast of Central America, contributing to the biodiversity record in Nicaragua.
29
Heatwole, Harold, Alana Grech, John F. Monahan, Susan King, and Helene Marsh. "Thermal Biology of Sea Snakes and Sea Kraits1." Integrative and Comparative Biology 52, no. 2 (June 4, 2012): 257–73. http://dx.doi.org/10.1093/icb/ics080.
Full text
30
Hampton, Paul M. "Interspecific variation in organ position in hydrophiine snakes is explained by modifications to the vertebral column." Biological Journal of the Linnean Society 128, no. 3 (August 30, 2019): 651–56. http://dx.doi.org/10.1093/biolinnean/blz121.
Full textAbstract:
Abstract Interspecific disparities in the position of the internal organs of snakes have been associated with evolutionary history and cardiovascular performance, as influenced by habitat use. For snakes, the positions of internal organs are typically determined as a linear measurement relative to body length. Therefore, interspecific variation in organ position could be explained either as heterotopic shifts in organ position or by modifications to the vertebral column. Using vertebral counts from radiographs, I determined the positions of the atria and pyloric sphincter relative to the cloaca in hydrophiine sea snakes. I found interspecific variation in the number of pre-atrial vertebrae to be labile, whereas the number of vertebrae in the atria to pyloric sphincter region and in the pyloric sphincter to cloaca region was relatively constrained. Furthermore, the number of pre-atrial vertebrae was dissociated from the number of vertebrae between the atria and cloaca, indicating that these two regions of the vertebral column can evolve independently. I conclude that variation in organ position among hydrophiine sea snake species is attributable, in part, to differences in the number of vertebrae among regions of the vertebral column rather than to heterotopic shifts in the positions of the internal organs.
31
Engeman, Richard M., Michael A. Linnell, Phillip Aguon, Anthony Manibusan, Steven Sayama, and Anthony Techaira. "Implications of brown tree snake captures from fences." Wildlife Research 26, no. 1 (1999): 111. http://dx.doi.org/10.1071/wr97110.
Full textAbstract:
The capture of brown tree snakes (Boiga irregularis) from fence lines in the vicinities of air and sea ports is an important component of the integrated approach used for curtailing the dispersal of the species from Guam. Use of fences by brown tree snakes was characterised from over 600 captures of snakes during spotlight searches. Two construction designs of chain-link fences were searched, the difference being whether a horizontal bar or a steel cable was used to support the chain link on top. Both fence designs had snakes concentrated at the fence tops – fences having top bars produced 92% of captures on the top third of the chain link, the top bar, or the parallel barbed-wire strands above the fence; fences without top bars produced 82% of captures from the top third of the chain link or the wires above it. Most snakes were found in a horizontal position and no general trends were found through the night for when snakes ascend or descend the fences. To help concentrate snakes at the tops of fences for facilitating control efforts, we recommend the use of a horizontal bar to support the chain link on top, as well as the use of parallel barbed- wire strands above the fence. We discuss management implications for using searches of fences to control brown tree snakes and to detect new brown tree snake populations in other locales.
32
Galbraith, James D., Alastair J. Ludington, Alexander Suh, Kate L. Sanders, and David L. Adelson. "New Environment, New Invaders—Repeated Horizontal Transfer of LINEs to Sea Snakes." Genome Biology and Evolution 12, no. 12 (October 6, 2020): 2370–83. http://dx.doi.org/10.1093/gbe/evaa208.
Full textAbstract:
Abstract 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.
33
Koleva, Vanya, Yurii Kornilev, Ivan Telenchev, Simeon Lukanov, Berna Hristova, and Nikolay Natchev. "Salt tolerance's toll: prolonged exposure to saline water inflicts damage to the blood cells of dice snakes (<i>Natrix tessellata</i>)." Web Ecology 17, no. 1 (January 24, 2017): 1–7. http://dx.doi.org/10.5194/we-17-1-2017.
Full textAbstract:
Abstract. Dice snakes (Natrix tessellata, Laurenti, 1768) inhabit oligohaline and brackish waters along the Bulgarian Black Sea coast, where they often forage at sea. Under these conditions, this species should tolerate highly variable blood plasma sodium concentrations for extended time periods, but the effect of high sodium concentrations to blood cell morphology and physiology is largely unknown. In this experiment, we placed adult dice snakes in waters with different salinity for 84 h, representing the three typical saline concentrations in which dice snakes live and forage: 0.2 ‰ NaCl, fresh water, 16 ‰ NaCl, Black Sea water and 36 ‰ NaCl, World Ocean water. We collected blood through cardiocentesis after exposure to each treatment and used Giemsa's solution for staining the formed elements. We registered numerous nuclear abnormalities (nuclear buds, lobes and blebs) in the blood cells of all investigated specimens. In the snakes placed in the waters with high saline concentration (16 and 36 ‰ NaCl) we found numerous cells with ruptured membranes. These snakes also showed increased mitochondrial activity compared to those in fresh water (1.85 and 2.53 times higher, respectively). Our data suggest that even though dice snakes show a remarkable tolerance to waters with increased salinity, prolonged exposure to it induces significant physiological stress in N. tessellata, which poses a clear limit for their ability to stay in the sea for a long time.
34
Tan, Choo Hock, and Kae Yi Tan. "De Novo Venom-Gland Transcriptomics of Spine-Bellied Sea Snake (Hydrophis curtus) from Penang, Malaysia—Next-Generation Sequencing, Functional Annotation and Toxinological Correlation." Toxins 13, no. 2 (February 9, 2021): 127. http://dx.doi.org/10.3390/toxins13020127.
Full textAbstract:
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.
35
Wang, Bo, Guoyan Liu, Min Luo, Xin Zhang, Qianqian Wang, Shuaijun Zou, Fuhai Zhang, Xia Jin, and Liming Zhang. "Preparation and Evaluation of a Horse Antiserum against the Venom of Sea Snake Hydrophis curtus from Hainan, China." Toxins 14, no. 4 (April 1, 2022): 253. http://dx.doi.org/10.3390/toxins14040253.
Full textAbstract:
Sea snake venom is extremely toxic, and it can induce severe respiratory failure and cause high mortality. The most effective first aid treatment for sea snake bites is to inject antivenom as soon as possible. However, in China, there are only four types of terrestrial snake antivenoms, none of which are effective in the treatment of sea snake bites. In order to develop an antivenom for the dominant species of sea snakes in Chinese seas, Hydrophis curtus venom (HcuV) was chosen as the antigen to immunize horses. From immune plasma, a high-titer Hydrophis curtus antivenom (HcuAV) was prepared. In vitro assessment showed that HcuAV had a cross-neutralizing capacity against HcuV and Hydrophis cyanocinctus venom (HcyV). In vivo assessment indicated that HcuAV injection could significantly improve the survival rates of the HcuV and HcyV envenomated mice (0% to 100% and 87.5%, respectively) when it was injected at a sufficient amount within the shortest possible time. In addition, HcuAV could also effectively alleviate multiple organ injuries caused by HcuV. These results provide experimental support for the future clinical application of HcuAV.
36
Hampton, Paul M. "Foraging ecology influences the number of vertebrae in hydrophiine sea snakes." Biological Journal of the Linnean Society 128, no. 3 (August 30, 2019): 645–50. http://dx.doi.org/10.1093/biolinnean/blz115.
Full textAbstract:
Abstract The number of vertebrae in snakes is highly variable both within and among species. Across ophidian taxa, the number of vertebrae has been linked to many aspects of ecology and performance. Herein, I test the hypothesis that variation in the number of vertebrae and the length of the anterior region of sea snakes are associated with foraging ecology. I predicted that sea snakes that invade burrows and crevices for prey would have relatively longer anterior regions as a result of a greater number of vertebrae. Using radiographs, I counted the number of vertebrae between the head and atria and between the atria and cloaca for 22 species of hydrophiine sea snakes. The length between the cranium and atria was positively associated with the frequency of burrowing prey consumed. The number of vertebrae in the pre-atrial region showed a positive association with diet, although the analysis only approached statistical significance. No association was observed between diet and the number of vertebrae between the atria and cloaca, indicating that heart position is constrained with respect to the cloaca. These data indicate that sea snakes specializing on burrowing prey have adapted elongated, anterior regions of the body through an increased number of vertebrae.
37
Ward, TM. "Sea snake by-catch of prawn trawlers on the northern Australian continental shelf." Marine and Freshwater Research 47, no. 4 (1996): 631. http://dx.doi.org/10.1071/mf9960631.
Full textAbstract:
This paper describes and compares the sea snakes caught by vessels that target tiger prawns and endeavour prawns or that target the banana prawns Penaeus merguiensis and P. indicus. In 1989-90, 5203 sea snakes (14 species; 7 unidentified specimens) were purchased from fishers who trawled between Koolan Island and Cape York and participated in a dedicated carcass-tagging and data-collection programme. Hydrophines (11 species) represented 86.7% of the total catch. Aipysurines (3 species) represented 15.0% of specimens from vessels that targeted tiger prawns or endeavour prawns, but only 1.1% of specimens from vessels that targeted the banana prawns P. merguiensis and P. indicus. Prawn trawlers that operated between Koolan Island and Cape York during 1990 caught approximately 81 080 (� 13 670) sea snakes. Vessels that targeted tiger/endeavour prawns, P. merguiensis and P. indicus caught approximately 69260 (� 8750), 7200 (� 3250) and 4620 (� 1120) sea snakes respectively. The results emphasize the advantages of interactions between fishers and scientists and the need to assess separately the impacts of the three fisheries that constitute the northern prawn fishery.
38
Palci, Alessandro, Roger S. Seymour, Cao Van Nguyen, Mark N. Hutchinson, Michael S. Y. Lee, and Kate L. Sanders. "Novel vascular plexus in the head of a sea snake (Elapidae, Hydrophiinae) revealed by high-resolution computed tomography and histology." Royal Society Open Science 6, no. 9 (September 4, 2019): 191099. http://dx.doi.org/10.1098/rsos.191099.
Full textAbstract:
Novel phenotypes are often linked to major ecological transitions during evolution. Here, we describe for the first time an unusual network of large blood vessels in the head of the sea snake Hydrophis cyanocinctus . MicroCT imaging and histology reveal an intricate modified cephalic vascular network (MCVN) that underlies a broad area of skin between the snout and the roof of the head. It is mostly composed of large veins and sinuses and converges posterodorsally into a large vein (sometimes paired) that penetrates the skull through the parietal bone. Endocranially, this blood vessel leads into the dorsal cerebral sinus, and from there, a pair of large veins depart ventrally to enter the brain. We compare the condition observed in H. cyanocinctus with that of other elapids and discuss the possible functions of this unusual vascular network. Sea snakes have low oxygen partial pressure in their arterial blood that facilitates cutaneous respiration, potentially limiting the availability of oxygen to the brain. We conclude that this novel vascular structure draining directly to the brain is a further elaboration of the sea snakes' cutaneous respiratory anatomy, the most likely function of which is to provide the brain with an additional supply of oxygen.
39
Woodward, Aylin. "Toxic waters turn sea snakes black." New Scientist 235, no. 3139 (August 2017): 10. http://dx.doi.org/10.1016/s0262-4079(17)31601-9.
Full text
40
Murphy, Robert W. "Sea Snakes, by Harold Heatwole [Review]." Canadian field-naturalist 103, no. 2 (1989): 309–10. http://dx.doi.org/10.5962/p.356149.
Full text
41
Sever, David M., and Layla R. Freeborn. "Observations on the anterior testicular ducts in snakes with emphasis on sea snakes and ultrastructure in the yellow-bellied sea snake, Pelamis platurus." Journal of Morphology 273, no. 3 (October 24, 2011): 324–36. http://dx.doi.org/10.1002/jmor.11025.
Full text
42
Sherratt, Emma, Kate L. Sanders, Amy Watson, Mark N. Hutchinson, Michael S. Y. Lee, and Alessandro Palci. "Heterochronic Shifts Mediate Ecomorphological Convergence in Skull Shape of Microcephalic Sea Snakes." Integrative and Comparative Biology 59, no. 3 (May 7, 2019): 616–24. http://dx.doi.org/10.1093/icb/icz033.
Full textAbstract:
Abstract Morphological variation among the viviparous sea snakes (Hydrophiinae), a clade of fully aquatic elapid snakes, includes an extreme “microcephalic” ecomorph that has a very small head atop a narrow forebody, while the hind body is much thicker (up to three times the forebody girth). Previous research has demonstrated that this morphology has evolved at least nine times as a consequence of dietary specialization on burrowing eels, and has also examined morphological changes to the vertebral column underlying this body shape. The question addressed in this study is what happens to the skull during this extreme evolutionary change? Here we use X-ray micro-computed tomography and geometric morphometric methods to characterize cranial shape variation in 30 species of sea snakes. We investigate ontogenetic and evolutionary patterns of cranial shape diversity to understand whether cranial shape is predicted by dietary specialization, and examine whether cranial shape of microcephalic species may be a result of heterochronic processes. We show that the diminutive cranial size of microcephalic species has a convergent shape that is correlated with trophic specialization to burrowing prey. Furthermore, their cranial shape is predictable for their size and very similar to that of juvenile individuals of closely related but non-microcephalic sea snakes. Our findings suggest that heterochronic changes (resulting in pedomorphosis) have driven cranial shape convergence in response to dietary specializations in sea snakes.
43
Goiran, Claire, Gregory P. Brown, and Richard Shine. "Niche partitioning within a population of sea snakes is constrained by ambient thermal homogeneity and small prey size." Biological Journal of the Linnean Society 129, no. 3 (January 10, 2020): 644–51. http://dx.doi.org/10.1093/biolinnean/blz206.
Full textAbstract:
Abstract In many populations of terrestrial snakes, the phenotype of an individual (e.g. body size, sex, colour) affects its habitat use. One cause for that link is gape limitation, which can result in larger snakes eating prey that are found in different habitats. A second factor involves thermoregulatory opportunities, whereby individuals select habitats based upon thermal conditions. These ideas predict minimal intraspecific variation in habitat use in a species that eats small prey and lives in a thermally uniform habitat, such as the sea snake Emydocephalus annulatus, which feeds on tiny fish eggs and lives in inshore coral reefs. To test that prediction, we gathered data on water depths and substrate attributes for 1475 sightings of 128 free-ranging E. annulatus in a bay near Noumea, New Caledonia. Habitat selection varied among individuals, but with a preference for coral-dominated substrates. The body size and reproductive state of a snake affected its detectability in deep water, but overall habitat use was not linked to snake body size, colour morph, sex or pregnancy. A lack of ontogenetic shifts in habitat use allows extreme philopatry in E. annulatus, thereby reducing gene flow among populations and, potentially, delaying recolonization after local extirpation events.
44
Jacobs, L. L., M. J. Polcyn, L. H. Taylor, and K. Ferguson. "Sea-surface temperatures and palaeoenvironments of dolichosaurs and early mosasaurs." Netherlands Journal of Geosciences 84, no. 3 (September 2005): 269–81. http://dx.doi.org/10.1017/s0016774600021053.
Full textAbstract:
AbstractThe north-central Texas Cretaceous section and its contained fossils, as compared to sections at ‘Ein Yabrud in the eastern Mediterranean region, demonstrate that dolichosaurs and primitive mosasaurs inhabited marine environments at least from the intertidal zone to <100 m in depth. The small body size of dolichosaurs and primitive mosasaurs, and the association of Haasiasaurus with marine snakes at ‘Ein Yabrud, suggest similar temperature requirements to modern sea snakes and marine iguanas (Amblyrhynchus cristatus), specifically sea-surface temperatures between approximately 20° and 30° С The Cenomanian and Turonian stages are characterised by widespread shallow seas with relatively high sea-surface temperatures extending to at least 45° N and 65° S latitude. The distribution of dolichosaurs, mosasaurs and snakes during this interval contradicts palaeoclimate models that predict high (>30° C) equatorial sea-surface temperatures and a steep latitudinal temperature gradient in the Northern Hemisphere.
45
Lee, Michael S. Y., and Michael W. Caldwell. "Adriosaurus and the affinities of mosasaurs, dolichosaurs, and snakes." Journal of Paleontology 74, no. 5 (September 2000): 915–37. http://dx.doi.org/10.1017/s0022336000033102.
Full textAbstract:
The poorly-known, long bodied, limb-reduced marine lizard Adriosaurus suessi Seeley, 1881, is reassessed. Adriosaurus and a number of other marine lizards are known from Upper Cretaceous (Upper Cenomanian-Lower Turonian) marine carbonate rocks exposed along the Dalmatian coast of the Adriatic Sea, from Komen, Slovenia, to Hvar Island, Croatia. A revised vertebral count reveals 10 cervical, 29 dorsal, and at least 65 caudal vertebrae. The projections previously interpreted as hypapophyses are instead transverse processes. Openings on the anterior part of the skull, previously described as external nares, are probably internal nares. Important features not noted previously include accessory articulations on all presacral vertebrae, pachyostosis of dorsal vertebrae and ribs, and the presence of two pygal vertebrae. Phylogenetic analysis of 258 osteological characters and all the major squamate lineages suggests that Adriosaurus and dolichosaurs are successive sister-taxa to snakes. This is consistent with their long-bodied, limb-reduced morphology being intermediate between typical marine squamates (e.g., mosasaurs) and primitive marine snakes (pachyophiids). The analysis further reveals that up to five successive outgroups to living snakes (pachyophiids, Adriosaurus, dolichosaurs, Aphanizocnemus, and mosasauroids) are all marine, suggesting a marine (or at least, semi-aquatic) phase in snake origins. These phylogenetic results are robust whether multistate characters are ordered or unordered, thus refuting recent suggestions that snakes cluster with amphisbaenians and dibamids (rather than aquatic lizards) if multistate characters are left unordered. Also, the recent suggestion that Pachyrhachis shares synapomorphies with advanced snakes (macrostomatans) is shown to be poorly supported, because the reinterpretations of the relevant skull elements are unlikely and, even if accepted, the character states proposed to unite Pachyrhachis and advanced snakes are also present in more basal snakes and/or the nearest lizard outgroups, and are consequently primitive for snakes.
46
JAMISON, SIMON, EREZ MAZA, GUY SINAIKO, KARIN TAMAR, ALEX SLAVENKO, and SHAI MEIRI. "To be or not to be tchernovi: a taxonomic revision of the snake genus Micrelaps (Squamata: Serpentes), in Israel." Zootaxa 4881, no. 2 (November 19, 2020): 290–306. http://dx.doi.org/10.11646/zootaxa.4881.2.4.
Full textAbstract:
The enigmatic snake genus Micrelaps has uncertain phylogenetic affinities. The type species of the genus, Micrelaps muelleri, inhabits the Southern Levant. Snakes inhabiting the Jordan River Valley just south of the Sea of Galilee have been described as a new species, Micrelaps tchernovi, based on their distinct colour patterns, despite M. muelleri being well known to be variable in colour-pattern traits. Here we use morphological and molecular data to examine the taxonomic status and phylogenetic affinity of Levantine Micrelaps. We show that all scalation, colour, and pattern-related traits are extremely variable across the range of these snakes. Some morphological features show clinal variation related to temperature and precipitation, and snakes with a ‘tchernovi’ morph are merely at one end of a continuum of morphological variation. Both ‘classical muelleri’ and ‘tchernovi’ morphs occur in syntopy in the Jordan Valley and elsewhere in Israel. Against this background of high morphological variation, neutral genetic markers show almost no differentiation between snakes, no genetic structure is evident across populations, and no differences are to be found between the two putative species. We conclude that Levantine Micrelaps belongs to a single, morphologically variable, and genetically uniform species, Micrelaps muelleri, of which M. tchernovi is a junior synonym.
47
Nitschke, Charlotte R., Mathew Hourston, Vinay Udyawer, and Kate L. Sanders. "Rates of population differentiation and speciation are decoupled in sea snakes." Biology Letters 14, no. 10 (October 2018): 20180563. http://dx.doi.org/10.1098/rsbl.2018.0563.
Full textAbstract:
Comparative phylogeography can inform many macroevolutionary questions, such as whether species diversification is limited by rates of geographical population differentiation. We examined the link between population genetic structure and species diversification in the fully aquatic sea snakes (Hydrophiinae) by comparing mitochondrial phylogeography across northern Australia in 16 species from two closely related clades that show contrasting diversification dynamics. Contrary to expectations from theory and several empirical studies, our results show that, at the geographical scale studied here, rates of population differentiation and speciation are not positively linked in sea snakes. The eight species sampled from the rapidly speciating Hydrophis clade have weak population differentiation that lacks geographical structure. By contrast, all eight sampled Aipysurus–Emydocephalus species show clear geographical patterns and many deep intraspecific splits, but have threefold slower speciation rates. Alternative factors, such as ecological specialization, species duration and geographical range size, may underlie rapid speciation in sea snakes.
48
Shaw, Charles E. "SEA SNAKES AT THE SAN DIEGO ZOO." International Zoo Yearbook 4, no. 1 (December 18, 2007): 49–52. http://dx.doi.org/10.1111/j.1748-1090.1963.tb03613.x.
Full text
49
Lane, Amanda, and Richard Shine. "Phylogenetic relationships within laticaudine sea snakes (Elapidae)." Molecular Phylogenetics and Evolution 59, no. 3 (June 2011): 567–77. http://dx.doi.org/10.1016/j.ympev.2011.03.005.
Full text
50
BONNET, XAVIER, and FRANÇOIS BRISCHOUX. "Thirsty sea snakes forsake refuge during rainfall." Austral Ecology 33, no. 7 (November 2008): 911–21. http://dx.doi.org/10.1111/j.1442-9993.2008.01917.x.
Full text