The Irrawaddy dolphin (Orcaella brevirostris) is a euryhaline species of oceanic dolphin found in scattered subpopulations near sea coasts and in estuaries and rivers in parts of the Bay of Bengal and Southeast Asia. It closely resembles the Australian snubfin dolphin (of the same genus, Orcaella), which was not described as a separate species until 2005. It has a slate blue to a slate gray color. Although found in much of the riverine and marine zones of South and Southeast Asia, the only concentrated lagoon populations are found in Chilika Lake in Odisha, India and Songkhla Lake in southern Thailand.
No narrative description available for this taxon yet.
A DNA barcode is a short, standardised stretch of genes that works like a fingerprint — enough to tell one species from another. Below is the molecular trace Orcaella brevirostris has left across the world's sequence archives.
At a glance
DNA specimens96
BINs1
Marker genes11
eDNA detections86
Countries10
The DNA barcodethe species' typical barcode, built from every sequenced specimen
COI-5P1 551 bp consensus86 specimens
ACGT
▸ drag or hover over the strip to read any position — letter and how much it varies
Violet ticks below the strip = positions where individuals differ; flat = the species' unchanging signature. 99% of positions are identical in every specimen.
Where individuals differ — all 19 variable positions, in barcode order
Each circle is a barcode variant; bigger = more specimens, colour = region. Lines join the most similar variants and the tick marks count the mutations between them — a tight cluster is one “dialect”, a long line a more divergent lineage. Click a circle to list its actual specimens.
Diversity (π)0.43%
Haplotypes22
BIN1
Most divergent pair0.90%
Asia
Marker genes sequenced
★ the standard DNA barcode for this group — the short region actually read to tell this species apart. The rest are extra genes sequenced along the way.
★COI-5PCOIICOXIIICYTBND1ND2ND3ND4ND4LND5-0ND6
animal barcodemitochondrial
Organelle genome
Besides the big genome in the nucleus, cells carry a small, circular loop of DNA inside the cell's energy factories — the mitochondria. It is inherited almost only from the mother and is a leftover from ancient bacteria that moved into the cell. The mitochondrial markers above (ND*, COX, CYTB…) are read from exactly this loop. Outer ring = one strand, inner ring = the other.
▸ Tap any coloured segment — or a gene chip — to see what it is
Pick a coloured segment on the ring — or a gene chip — to read what that gene does.
protein-codingrRNAtRNA
07Deep time0.01–0 Ma
How far back this lineage goes — and how we know. Everything here is measured in Ma, short for “mega-annum”: millions of years ago. The chart reads left to right like a calendar of the Earth, from the deep past on the left to today at the right edgetop to bottom like a core drilled through the Earth, from the deep past at the top down to today at the bottom.
At a glance
Fossil range0.01–0 Ma Pleistocene, Holocene
Dated fossil finds5
StatusStill living record runs to the present
When this lineage existed
How to read this: the coloured strip along the bottomdown the left is the geological calendar — the standard epochs (Pliocene, Pleistocene…) every museum uses, shown so you can see which chapter of Earth's history this lineage lived in. This lineage is a young one, so the strip is zoomed in to epochs — the finer subdivisions inside a period. The solid bar is the fossil range: the span between the oldest and the youngest fossil that palaeontologists have assigned to Orcaella brevirostris. Above itBeside it, each dot is one dated fossil find — few enough to count, so they are drawn individually rather than as a graph.
fossil range (PBDB)each dot = one dated find
How it livedPBDB
Environmentmarine,freshwater
Life habitaquatic, depth=surface
Dietpiscivore, carnivore
Motilityactively mobile
Compositionhydroxyapatite
Reproductionviviparous
Ontogenymodification of parts
08Occurrence & distribution
Record type1 016 records
Wild obs. + sensor977
Museum / vouchered34
Fossil5
Range
Area of Occupancy AOO1 124 km²
Wildobservation + sensor
Human sightings and records, or camera-trap / sensor detections — someone (or a device) saw or captured the species in the wild.
Coordinate accuracy36% within 1 km
≤100 m 105≤1 km 16>10 km 216
337 georeferenced · 640 without coordinates
Open the mapobservation + sensor977
Museum / Voucheredphysical evidence
Backed by a physical specimen — a herbarium sheet, sample or voucher held in a collection. “Vouchered” means supported by material evidence, not just an observation.
Coordinate accuracy100% within 1 km
≤100 m 2≤1 km 29
31 georeferenced · 3 without coordinates
Open the institutions mapphysical evidence34
Wildobservation + sensor
Human sightings and records, or camera-trap / sensor detections — someone (or a device) saw or captured the species in the wild.
10Collections & institutions
Holding institutions2 of 2 geolocated
Institutions and collections holding physical, vouchered specimens of this species — click a row to fly to it on the map.
Institution
Specimens
Chicago, US
2
Washington, US
1
2 institutions · 3 of 34 vouchered records shown · 30 without an institution code
09Environmental DNA86 detections
Where the DNA of Orcaella brevirostris was picked up in samples of water, soil or air — nobody saw the organism, only its DNA left behind. A trace is a clue that the species was near, not a confirmed sighting.
Signal
Detections DNA found86
Studies independent surveys1
Countries1
Signal confidence: weakweighed across independent studies, places & mapped detections
Where its DNA was found
0 of 86 detections have coordinates
Open the map1 country0
How strong is each trace?
DNA read depthRead counts were not reported for this species — the map shows presence only, not how strong each trace was.
Modelled climatemodelled
−15°Ctemperature across detection sites+40°C
Temperature median25.9 °C 25.9–25.9
Seasonal swing summer↔winter0.5 °C
Max temp (day)29.8 °C
Min temp (night)22.3 °C
Precipitation343 mm/mo
Air humidity69.6 %
Moisture balance205 mm/mo
Vapour deficit1,012 Pa
Wind speed0.6 m/s
Cloud cover57.4 %
CHELSA 1981–2010, ~9 km grid, at location & month of 1 detection point · median with p10–p90 · reflects where sampling happened, not only the true niche
How to read this: each dot is one detection of this species' DNA in an environmental sample. The confidence meter weighs how many independent studies and places back up the signal — one detection in one study is a hint; many across several studies is solid. Records dated before 2008 (when eDNA methods began) are treated as likely mislabeled and left off the map.
WikipediaWikimedia Foundation21 languages↗
Animal Diversity WebUniv. of Michigan MZspecies account↗
BioWikiNetmultilingual Wikipediamultilingual↗
GBIFGlobal Biodiversity Information Facility657 records↗
OBISOcean Biodiversity Information System354 records↗
ENAEuropean Nucleotide Archive · EMBL-EBI86 eDNA detections↗
BOLD SystemsCentre for Biodiversity Genomics96 specimens↗
Open Tree of LifeOpenTreephylogeny backbone↗
Paleobiology DatabasePBDB consortiumfossil record↗
WikidataWikimedia Foundationstructured facts↗
GLoBIGlobal Biotic Interactionsbiotic interactions↗