Editing Mesoplodon

{{Short description|Genus of beaked whales}}
{{Automatic taxobox
| image = Faroe stamp 197 Mesoplodon bidens.jpg
| image_caption = [[Sowerby's beaked whale]] (on Faroese stamp)
| taxon = Mesoplodon
| authority = [[Paul Gervais|Gervais]], 1850
| type_species = ''[[Mesoplodon bidens|Delphinus sowerbensis]]'' <ref>{{MSW3|id=14300157}}</ref>
| type_species_authority = de Blainville, 1817
| subdivision_ranks = [[Species]]
| subdivision = 16, ''See text''.
}}

'''Mesoplodont whales''' are 16 [[species]] of [[toothed whale]] in the genus '''''Mesoplodon''''', making it the largest genus in the cetacean [[order (biology)|order]].<ref name="Pitman-intro">{{Harvnb|Pitman|2008|p=721}}</ref>  Two species were described as recently as 1991 (pygmy beaked whale) and 2002 (Perrin's beaked whale), and [[marine biologist]]s predict the discovery of more species in the future.<ref name="Pitman-char-taxo" />  A new species was described in 2021.{{sfn|Carroll|McGowen|McCarthy|Marx|2021}} They are the most poorly known group of large mammals.<ref name="Pitman-intro" />  The generic name "mesoplodon" comes from the [[Greek language|Greek]] ''meso''- (middle) - ''hopla'' (arms) - ''odon'' (teeth), and may be translated as 'armed with a tooth in the centre of the jaw'.<ref name="Pitman-char-taxo">{{Harvnb|Pitman|2008|loc=Characters and Taxonomic Relationships, pp. 721–724}}</ref>

==Physical description==
[[File:Scars from cookie-cutter shark bites on Gray's beaked whale.jpg|thumb|upright|alt=The flank of a stranded whale, showing several round scars|Round scars from cookiecutter shark bites can be seen on the flank of this stranded Gray's beaked whale.]]
Mesoplodont beaked whales are small whales, {{Convert|3.9|m|abbr=on}} (pygmy beaked whale) to {{Convert|6.2|m|abbr=on}} (strap-toothed whale) in length,<ref name="Pitman-char-taxo" /> even compared with closely related whales such as the [[bottlenose whale]]s and [[giant beaked whale]]s.
The spindle-shaped body has a small dorsal fin and short and narrow flippers.  The head is small and tapered and has a semicircular blow hole that is sometimes asymmetric. The beak, which vary in length between species, blends with the small melon without a crease.<ref name="Pitman-char-taxo" />

Sexual dimorphism is poorly known, but the females tend to be the same size or larger than males at least in some species.<ref name="Pitman-char-taxo" />  The males typically have a bolder coloration and a unique dentition.
The males of most species are covered in scars from the teeth of other males.

The lower jaw often forms a huge arch in some species, sometimes extending above the rostrum in a shape comparable to a playground slide. Every species has large (sometimes tusk-like) teeth of variable size, shape, and position.

Both sexes often have bites from [[cookie-cutter shark]]s. The [[dorsal fin]] is rather small and located between two-thirds and three-quarters down the back of the animal. Information on longevity and lactation is non-existent, and information on gestation is nearly so.

==Behavior==
Most species are very rarely observed, and little is known about their behavior.<ref name="Pitman-intro" /> They are typically found in groups, possibly segregated between sexes. Some species are so uncommon, they have yet to be observed alive.<ref name="Pitman-intro" /> On the surface, they are typically very slow swimmers and do not make obvious blows. They have never been observed raising their flukes above the water. They are all very deep divers, and many feed entirely on squid.

==Conservation==
The mesoplodonts are completely unknown as far as population estimates are concerned. They have been hunted occasionally by the Japanese, but never directly. They are also accidentally captured in [[drift net]]s. It is not known what effect this has on the population.

==Species==
* [[Andrews' beaked whale]] (''M. bowdoini'') <small>Andrews, 1908</small>
* [[Blainville's beaked whale]] (''M. densirostris'') <small>Blainville, 1817</small>
* [[Deraniyagala's beaked whale]] (''M. hotaula'') <small>[[Paules Edward Pieris Deraniyagala|Deraniyagala]], 1963</small><ref>{{Harvnb|Dalebout|Baker|Steel|Thompson|2014}}</ref>
* [[Gervais's beaked whale]] (''M. europaeus'') <small>Gervais, 1855</small>
* [[Ginkgo-toothed beaked whale]] (''M. ginkgodens'') <small>Nishiwaki and Kamiya, 1958</small>
* [[Gray's beaked whale]] (''M. grayi'') <small>von Haast, 1876</small>
* [[Hector's beaked whale]] (''M. hectori'') <small>Gray, 1871</small>
* [[Hubbs' beaked whale]] (''M. carlhubbsi'') <small>Moore, 1963</small>
* [[Perrin's beaked whale]] (''M. perrini'') <small>Dalebout, Mead, Baker, Baker & van Helden, 2002</small>
* [[Pygmy beaked whale]] (''M. peruvianus'') <small>Reyes, Mead, and Van Waerebeek, 1991</small>
* [[Sowerby's beaked whale]] (''M. bidens'') <small>Sowerby, 1804</small>
* [[Spade-toothed whale]] (''M. traversii'') <small>Gray, 1874</small>
* [[Stejneger's beaked whale]] (''M. stejnegeri'') <small>True, 1885</small>
* [[Strap-toothed whale]] (''M. layardii'') <small>Gray, 1865</small>
* [[True's beaked whale]] (''M. mirus'') <small>True, 1913</small>
*[[Ramari's beaked whale]] (''M. eueu'') <small>Carroll ''et al'', 2021</small>{{sfn|Carroll|McGowen|McCarthy|Marx|2021}}

[[Longman's beaked whale]] (''Indopacetus pacificus'', also known as the Indo-Pacific beaked whale or the tropical bottlenose whale) was originally assigned to ''Mesoplodon'', but Joseph Curtis Moore placed it in its own genus, ''[[Indopacetus]]'', a taxonomic assignment which has been followed by all researchers.<ref name="Pitman-char-taxo" />

Four extinct species of ''Mesoplodon'' are known: ''M.&nbsp;longirostris''<ref>{{Cite journal |last=Bianucci |first=Giovanni |date=1997 |title=The Odontoceti (Mammalia, Cetacea) from Italian Pliocene. Systematics and phylogenesis of Delphinidae |url=https://www.researchgate.net/publication/292704391_The_Odontoceti_Mammalia_Cetacea_from_Italian_Pliocene_Systematics_and_phylogenesis_of_Delphinidae |journal=Palaeontographia Italica}}</ref> ''M.&nbsp;posti'',<ref>Olivier Lambert and Stephen Louwye (2016). "[[A new early Pliocene species of Mesoplodon: a calibration mark for the radiation of this species-rich beaked whale genus]]". Journal of Vertebrate Paleontology 36 (2): e1055754. {{doi|10.1080/02724634.2015.1055754}}.</ref> ''M.&nbsp;slangkopi''.<ref>G. Bianucci, O. Lambert, and K. Post. 2007. [[A high diversity in fossil beaked whales (Mammalia, Odontoceti, Ziphiidae) recovered by trawling from the sea floor off South Africa]]. Geodiversitas 29(4):561-618</ref> and ''M.&nbsp;tumidirostris''.<ref>Miyazaki, N.; Hasegawa, Y. 1992: [[A new species of fossil beaked whale, Mesoplodon tumidirostris sp. nov. (Cetacea, Ziphiidae) from the Central North Pacific]]. Bulletin of the National Science Museum (A), 18: 167–174.</ref>

<gallery mode="packed">
File:Mesoplodon bidens British mammals (Pl. 46) (21866206616).jpg|[[Sowerby's beaked whale]], ''Mesoplodon bidens''; a male, with conspicuous teeth in the lower jaw
File:Andrews' Beaked Whale (neonate, beachwashed) (cropped).JPG|A stranded newborn [[Andrews' beaked whale]], ''M.&nbsp;bowdoini''
File:Hubbs' beaked whale skull.jpg|Skull of a [[Hubbs' beaked whale]] (''M. carlhubbsi'')
File:Beaked Whale.jpg|[[Blainville's beaked whale]] (''M. densirostris'') in the [[Bahamas]]
File:Gervais' Beaked Whale.jpg|[[Gervais's beaked whale]] (''M. europaeus'') in the [[Gulf Stream]] off [[North Carolina]]
File:Researchers conduct autopsy on stranded beaked whale.jpg|Autopsy of a stranded [[Gray's beaked whale]] (''M.&nbsp;grayi'')
File:First underwater video of True's beaked whales underwater.ogv|[[True's beaked whale]] (''M. mirus'') off the [[Azores]]
File:Mesoplodon traversii.svg|The [[Spade-toothed whale]] (''M. traversii'') was only morphologically described in 2012.
</gallery>

==References==

===Notes===
{{Reflist}}

===Sources===
{{Refbegin}}
* {{Cite journal
 | last1 = Dalebout | first1 = M. L.
 | last2 = Baker | first2 = C. S.
 | last3 = Steel | first3 = D.
 | last4 = Thompson | first4 = K.
 |author5=Robertson, K. M. |author6=Chivers, S. J. |author7=Perrin, W. F. |author8=Goonatilake, M. |author9=Anderson, R. C. |author10=Mead, J. G. |author11=Potter, C. W. |author12=Thompson, L. |author13=Jupiter, D. |author14=Yamada, T. K.
 | title = ''Mesoplodon hotaula'': Resurrection of Mesoplodon hotaula Deraniyagala, 1963: A New Species of Beaked Whale in the tropical Indo-Pacific
 | year = 2014 | journal = Marine Mammal Science | volume = 30 | issue = 3 | pages = 1081–1108
 | doi = 10.1111/mms.12113 | hdl = 1957/51503 | hdl-access = free }}<!-- {{Harvnb|Dalebout|Baker|Steel|Thompson|2014}} -->
* {{Cite book
 | last = Pitman | first = R.
 | chapter = Mesoplodont Whales (''Mesoplodon'' spp.) | pages = 721–726
 | title = Encyclopedia of Marine Mammals
 | editor1-last = Perrin | editor1-first = W. F.
 | editor2-last = Würsig | editor2-first = B.
 | editor3-last = [[Hans Thewissen|Thewissen]]| editor3-first = J. G. M.
 | year = 2008 | publisher = Academic Press | edition = 2nd
 | isbn = 978-0-12-373553-9 }}<!-- {{Harvnb|Pitman|2008}} -->
*{{cite journal |last1=Carroll |first1=Emma L. |last2=McGowen |first2=Michael R. |last3=McCarthy |first3=Morgan L. |last4=Marx |first4=Felix G. |last5=Aguilar |first5=Natacha |last6=Dalebout |first6=Merel L. |last7=Dreyer |first7=Sascha |last8=Gaggiotti |first8=Oscar E. |last9=Hansen |first9=Sabine S. |last10=van Helden |first10=Anton |last11=Onoufriou |first11=Aubrie B. |last12=Baird |first12=Robin W. |last13=Baker |first13=C. Scott |last14=Berrow |first14=Simon |last15=Cholewiak |first15=Danielle |last16=Claridge |first16=Diane |last17=Constantine |first17=Rochelle |last18=Davison |first18=Nicholas J. |last19=Eira |first19=Catarina |last20=Fordyce |first20=R. Ewan |last21=Gatesy |first21=John |last22=Hofmeyr |first22=G. J. Greg |last23=Martín |first23=Vidal |last24=Mead |first24=James G. |last25=Mignucci-Giannoni |first25=Antonio A. |last26=Morin |first26=Phillip A. |last27=Reyes |first27=Cristel |last28=Rogan |first28=Emer |last29=Rosso |first29=Massimiliano |last30=Silva |first30=Mónica A. |last31=Springer |first31=Mark S. |last32=Steel |first32=Debbie |last33=Olsen |first33=Morten Tange |title=Speciation in the deep: genomics and morphology reveal a new species of beaked whale Mesoplodon eueu |journal=Proceedings of the Royal Society B: Biological Sciences |date=27 October 2021 |volume=288 |issue=1961 |pages=20211213 |doi=10.1098/rspb.2021.1213 |url=https://royalsocietypublishing.org/doi/10.1098/rspb.2021.1213 |access-date=27 October 2021|doi-access=free |pmc=8548795 }}
{{Refend}}

== External links ==
* Carly Cassella: [https://www.sciencealert.com/scientists-think-they-ve-identified-a-whole-new-species-of-whale-off-the-coast-of-mexico Scientists Think They've Discovered a New Species of Beaked Whale]. On: science<sup>alert</sup> 12 December 2020

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[[Category:Ziphiids]]
[[Category:Taxa named by Paul Gervais]]
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