Rhizoprionodon acutus

The milk shark is a species of requiem shark, and part of the family Carcharhinidae, whose common name comes from an old Indian belief that consumption of its meat promotes lactation. The largest and most widely distributed member of its genus, the milk shark typically measures 1.1 m (3.6 ft) long, and can be found in coastal tropical waters throughout the eastern Atlantic and the Indo-Pacific regions. Occurring from the surface to a depth of 200 m (660 ft), this species is common near beaches and in estuaries, and has been recorded swimming up rivers in Cambodia. Juveniles are known to inhabit tidal pools and seagrass meadows. The milk shark has a slender body with a long, pointed snout and large eyes, and is a nondescript gray above and white below. This shark can be distinguished from similar species in its range by the long furrows at the corners of its mouth, and seven to 15 enlarged pores just above them.

Rhizoprionodon acutus

Karunakar Rayker from India · CC BY 2.0 · via Wikipedia/Commons. May be a photograph of a specimen, or an artist’s reconstruction — an interpretation of a skeleton, since colour and soft tissue are almost never preserved.

On record

Recorded, not inferred
Also called
milk sharkPBDB
Sits inside
RhizoprionodonPBDB
Diet
carnivorePBDB, for Carcharhiniformes
Life habit
nektonicPBDB, for Carcharhiniformes
Motility
actively mobilePBDB, for Carcharhiniformes

Time the record covers

At least 21 million years on record.

The record covers at least 23.04 Mya to 1.8 Mya. No occurrence read is dated outside 27.3 Mya to 774 ka.

Oligocene — about 1 of 5 occurrencesOligoceneMiocene — about 1 of 5 occurrencesMiocenePliocene — about 2 of 5 occurrencesPliocenePleistocene — about 1 of 5 occurrencesPleistocene28–27 Mya — about 0.1 occurrences27–26 Mya — about 0.2 occurrences26–25 Mya — about 0.2 occurrences25–24 Mya — about 0.2 occurrences24–23 Mya — about 0.2 occurrences23–22 Mya — about 0.1 occurrences22–21 Mya — about 0.1 occurrences21–20 Mya — about 0.1 occurrences20–20 Mya — about 0.1 occurrences20–19 Mya — about 0.1 occurrences19–18 Mya — about 0.1 occurrences18–17 Mya — about 0.1 occurrences17–16 Mya — about 0.1 occurrences5.8–4.8 Mya — about 0.6 occurrences4.8–3.9 Mya — about 1 occurrence3.9–3.0 Mya — about 0.4 occurrences2.1–1.2 Mya — about 0.6 occurrences1.2–243 ka Mya — about 0.4 occurrences23.04 Mya1.8 Mya27.8 Mya243 ka

5 occurrences of Rhizoprionodon acutus on record, most of them in the Pliocene. The Paleobiology Database records this as a living group, and the chart stops with its fossils rather than at the present. Bar height is expected occurrences, not a count: each fossil is spread across the span it is dated to, so a tall narrow bar means tight dating and a low wide one means loose.

When

5 occurrences

These are dates about fossils, not the animal: the record can only begin after it arose and end before it died out, so either end may reach further. Shares are expected occurrences: a fossil dated to a span is counted partly in each period it straddles. More on what this infers.

Found in

3 formations

Jan Juc — 38.20°S, 144.27°EBhuban — 23.75°N, 92.68°ELiuchungchi — 23.44°N, 120.59°E

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The named rock units Rhizoprionodon acutus has been recovered from, largest first. Drawn where the rock is now, not where it formed. 2 occurrences have no formation on record, which is common for older literature.

Rhizoprionodon acutus and its relatives

Pliocene

Where Rhizoprionodon acutus and its relatives were recorded in the Pliocene.

Found in the same rock

124 taxa

The Paleobiology Database records 5 sites for Rhizoprionodon acutus, and this reads all of them. The number is how many of those sites it was catalogued from too. The 24 sharing the most are listed.

This is not a list of everything alive at the time. It is only what has come out of the same ground as this animal and been written down.

Entered from

5 references

Each of the 5 occurrences read was entered from one of these publications, ordered by how many each accounts for. This is not a search for papers mentioning the name. Entries link to doi.org where the Paleobiology Database holds an identifier, and to its own record where it does not. Relayed as the Paleobiology Database holds them, not checked against what they resolve to.

Media and terms

Media content1

Picture of Rhizoprionodon acutus

Credit
Karunakar Rayker from India
Licence
CC BY 2.0
Commercial use
the licence allows it

No 3D scan of Rhizoprionodon acutus was found in MorphoSource and Sketchfab.

Smithsonian Open Access was not reached for this taxon, so this list is what the others held rather than everything there is.

The description on this site

Licence
CC BY-SA 4.0

This is what the site found, which is not the same as what exists.

Keep going

What may have been alongside itRhizoprionodon through timeFormations of the PlioceneThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. (Rüppell 1837)