Find research datasets worth reusing
Search datasets from major research repositories and use ShareScore to quickly assess how well each record supports discovery, access, and reuse.
15
datasets available to search
ShareScore release 0.9.0
Dataset results
15 results for “Emydocephalus”
Colour polymorphism in the sea snake Emydocephalus annulatus
<p>Evolutionary theory suggests that polymorphic traits can be maintained within a single population only under specific conditions, such as negative frequency-dependent selection or heterozygote advantage. Non-venomous turtle-headed sea snakes (<em>Emydocephalus annulatus</em>) living in shallow bays near Noumea in New Caledonia exhibit three colour morphs: black, black-and-white banded, and an intermediate (grey-banded) morph that darkens with age. We recorded morph frequencies during 18 consecutive years of surveys, and found that the numbers of recruits (neonates plus immigrants) belonging to each morph increased in years when that morph was unusually rare in the population, and decreased when that morph was unusually common. Thus, morph frequencies are maintained by negative frequency-dependent selection. We interpret the situation as Batesian mimicry of highly venomous sea snakes (<em>Aipysurus</em>, <em>Hydrophis</em>, <em>Laticauda</em>) that occur in the same bays, and range in colour from black-and-white banded to grey-banded. Consistent with the idea that mimicry may protect snakes from attack by large fish and sea eagles, behavioural studies have shown that smaller fish species in these bays flee from banded snakes but attack black individuals. As predicted by theory, mimetic (banded) morphs are less common than the cryptically-coloured melanic morph.</p>
Sexual dimorphism in size and shape of the head in the sea snake Emydocephalus annulatus
<p>In snakes, divergence in head size between the sexes has been interpreted as an adaptation to intersexual niche divergence. By overcoming gape-limitation, a larger head enables snakes of one sex to ingest larger prey items. Under this hypothesis, we do not expect a species that consumes only tiny prey items to exhibit sex differences in relative head size, or to show empirical links between relative head size and fitness-relevant traits such as growth and fecundity. Our field studies on the sea snake <i>Emydocephalus annulatus</i> falsify these predictions. Although these snakes feed exclusively on fish eggs, the heads of female snakes are longer and wider than those of males at the same body length. Individuals with wider heads grew more rapidly, reproduced more often, and produced larger litters. Thus, head shape can affect fitness and can diverge between the sexes even without gape-limitation. Head size and shape may facilitate other aspects of feeding (such as the ability to scrape eggs off coral) and locomotion (hydrodynamics); and a smaller head may advantage the sex that is more mobile, and that obtains its prey in narrow crevices rather than in more exposed situations (i.e., males).</p>
Sexual dimorphism in size and shape of the head in the sea snake Emydocephalus annulatus
Open the record for dataset details and reuse information.
Colour polymorphism in the sea snake Emydocephalus annulatus
Open the record for dataset details and reuse information.
FIGURE 5 in A new species of turtle-headed sea Snake (Emydocephalus: Elapidae) endemic to Western Australia
FIGURE 5. Holotype of Emydocephalus orarius sp. nov. WAM R165708 dorsal (A); Ventral (B); cephalic scalation (C); and paratype WAM R73661 (D)
FIGURE 7 in A new species of turtle-headed sea Snake (Emydocephalus: Elapidae) endemic to Western Australia
FIGURE 7. Emydocephalus species in life: Emydocephalus orarius sp. nov from Pilbara (A) and Shark Bay (B) (DPIRD), Emydocephalus annulatus from the Timor Sea (C) (Jenna Crowe-Riddell) and Emydocephalus ijimae from Okinawa (D) (Vladimir Dinets).
Population dynamics of the sea snake Emydocephalus annulatus
<p>For sea snakes as for many types of animals, long-term studies on population biology are rare and hence, we do not understand the degree to which annual variation in population sizes is driven by density-dependent regulation versus by stochastic abiotic factors. We monitored three populations of turtle-headed sea snakes (<i>Emydocephalus annulatus</i>) in New Caledonia over an 18-year period. Annual recruitment (% change in numbers) showed negative density-dependence: that is, recruitment increased when population densities were low, and decreased when densities were high. Windy weather during winter increased survival of neonates, perhaps by shielding them from predation; but those same weather conditions reduced body condition and the reproductive output of adult snakes. The role for density-dependence in annual dynamics of these populations is consistent with the slow, K-selected life-history attributes of the species; and the influence of weather conditions on reproductive output suggests that females adjust their allocation to reproduction based on food availability during vitellogenesis.</p>
Divergence in life-history traits among three populations of the sea snake Emydocephalus anulatus
<p><span>Life-history traits such as rates of growth, survival and reproduction can vary though time within a single population, or through space among populations, due to abiotically-driven changes in resource availability. In terrestrial reptiles, parameters such as temperature and rainfall generate variation in life-histories – but other parameters likely are more important in marine systems. We studied three populations of sea snakes (<em>Emydocephalus annulatus</em>) in adjacent bays in the IndoPacific archipelago of New Caledonia. The extreme philopatry of individual snakes allows us to unambiguously allocate each animal to one of the three populations. Although water temperatures and rainfall do not differ over this small scale, one site experiences more intense winds, restricting opportunities for foraging. Our 18-year mark-recapture dataset (>1,200 snakes, >2,400 captures) reveals significant divergence among populations in life-history traits. Survival rates and population densities were similar among sites, but snakes at the most wind-exposed site (Anse Vata) exhibited lower body condition, slower growth, less frequent production of litters, and smaller litters. Weather-driven variation in feeding rates thus may affect life-history traits of marine snakes as well as their terrestrial counterparts, but driven by different parameters (e.g., wind exposure rather than variation in temperatures or rainfall).</span></p>
Divergence in life-history traits among three populations of the sea snake Emydocephalus anulatus
Open the record for dataset details and reuse information.
Population dynamics of the sea snake Emydocephalus annulatus
Open the record for dataset details and reuse information.
FIGURE 6 in A new species of turtle-headed sea Snake (Emydocephalus: Elapidae) endemic to Western Australia
FIGURE 6. Typical cephalic scalation in Emydocephalus annulatus (upper) and Emydocephalus orarius sp. nov. (lower)
FIGURE 4 in A new species of turtle-headed sea Snake (Emydocephalus: Elapidae) endemic to Western Australia
FIGURE 4. Maximum likelihood tree of Emydocephalus species using dataset. Scale bar represents nucleotide substitutions per base pair.
FIGURE 3 in A new species of turtle-headed sea Snake (Emydocephalus: Elapidae) endemic to Western Australia
FIGURE 3. ND4 maximum clade credibility species. Scale bar represents nucleotide substitutions per base pair.
FIGURE 1 in A new species of turtle-headed sea Snake (Emydocephalus: Elapidae) endemic to Western Australia
FIGURE 1. Distribution of Emydocephalus species. Compiled from tissue samples, museum records and literature (Alcala 2000; Dotsenko 2010; Rasmussen and Ineich, 2010). Green=E. orarius sp. nov.; yellow=E. ijimae; turquoise=E. annulatus (Timor Sea); blue=E. annulatus (Coral Sea); red=E. cf. annulatus (specific identity currently unclear).
FIGURE 2. Cytochrome b in A new species of turtle-headed sea Snake (Emydocephalus: Elapidae) endemic to Western Australia
FIGURE 2. Cytochrome b maximum clade credibility BEAST tree for Emydocephalus. Aipysurus species included for comparison.
ScienceDex guides
Understand access before you commit
These curated guides explain access requirements, typical timelines, costs, and reuse considerations for widely used research datasets.
Allen Brain Atlas
Allen Brain Atlas is an Allen Institute collection of brain map atlases, datasets, APIs, and analysis tools covering mouse, human, and non-human primate brain resources.
Annotated Behaviour and Observability Dataset (ABODe)
ABODe is a University of Edinburgh DataShare dataset for behavior classification in group-housed mice using home-cage video, identities, bounding boxes, ground-plate positions, and annotator labels.
DANDI Archive for NWB datasets
DANDI is a BRAIN Initiative archive for publishing and sharing neurophysiology data, including electrophysiology, optophysiology, and behavioral data packaged as NWB and related standards.
International Brain Laboratory public data
The International Brain Laboratory public data releases expose standardized mouse decision-making experiments, including Neuropixels recordings, widefield calcium imaging, behavior, and session metadata accessed through the ONE API.
OpenNeuro
OpenNeuro is a free, open platform for sharing neuroimaging datasets, with public search, dataset pages, and download paths for web, S3, DataLad, and the OpenNeuro CLI.