Physical Description

Morphology

Tooth morphology

Tooth position

A single pair of large teeth are positioned back from the apex at 50 - 60% of total length of the mouthline. The tooth root is squared at its base and the teeth have a slight anterior incline or no incline at all. This is the only mesoplodont to have maxillary teeth. Up to 17-22 regularly spaced maxillary teeth begin at the same position along the jaw as the single pair of teeth in the lower jaw. There are no alveoli and they protrude only a few millimeters external to the gum.

Tooth exposure

Erupted teeth of adult males are covered in gum tissue with only the tips of the teeth exposed. Teeth in females and juveniles do not erupt.

Tooth shape

Anterior and posterior tooth margins are sinusoidal with the tooth apex slightly offset from the midline of the tooth.

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Skull morphology

Diagnostic features of the skull and mandible

On the vertex of the dorsal skull the premaxillary bone extends forward of the nasal and frontal bones. Separates from Berardius and Ziphius.

A sulcus (groove) running along the middle of the combined surfaces of the nasal bones so depresses their combined middle that it is the lateral portion of each nasal bone that reaches farthest forward on the vertex. Separates from Tasmacetus and Indopacetus.

When the skull is upright and the long axis of the anterior half of the beak is horizontal, a horizontal plane transecting the summit of either maxillary prominence transects the mesethmoid bone. Separates from Hyperoodon.

Tooth alveoli of mandible are positioned b etween apex and posterior mandibular symphysis.Separates from Berardius, Ziphius, Tasmacetus,Indopacetus, Hyperoodon, M. bowdoini, M. carlhubbsi, M, ginkgodens, M. hectori, M. layardii, M. mirus, M. perrini, M. densirostris, M. peruvianus, M. stejnegeri, and M. traversii.

Deep basirostral groove extends anteriorly well past the prominental turbercle. Separates from M. bidens and M. europaeus.

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External morphology



Head Shape

The melon may bulge slightly or not at all in front of the blowhole and slopes smoothly to the long and pointed beak. The mouthline is relatively straight.

Coloration

Adult males are darkly pigmented over entire body except for the rostrum and lower jaw which are white. Females are dark gray on the dorsal surface and light gray on the ventral surface, with patches of white around the umbilical scar, genital and anal slit and mammary slits. The lower jaw and upper lips are light gray. The flippers are darker than the surrounding body.

Size

Adult body length ranges between 5.3 to 5.8 m. Recorded maximum body length for adult males and females is 5.6 m and 5.8 m, respectively. Length at birth is 2.4 m.

Most Likely Confused With:

Mesoplodon layardii

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Ecology

Habitat

Depth range based on 674 specimens in 11 taxa.
Water temperature and chemistry ranges based on 656 samples.

Environmental ranges
  Depth range (m): 0 - 0
  Temperature range (°C): -1.670 - 29.038
  Nitrate (umol/L): 0.026 - 27.643
  Salinity (PPS): 31.430 - 36.478
  Oxygen (ml/l): 4.582 - 8.094
  Phosphate (umol/l): 0.055 - 1.846
  Silicate (umol/l): 0.824 - 66.028

Graphical representation

Temperature range (°C): -1.670 - 29.038

Nitrate (umol/L): 0.026 - 27.643

Salinity (PPS): 31.430 - 36.478

Oxygen (ml/l): 4.582 - 8.094

Phosphate (umol/l): 0.055 - 1.846

Silicate (umol/l): 0.824 - 66.028
 
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.

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Molecular Biology and Genetics

Molecular Biology

Statistics of barcoding coverage

Barcode of Life Data Systems (BOLD) Stats
                                        
Specimen Records:23Public Records:17
Specimens with Sequences:17Public Species:2
Specimens with Barcodes:17Public BINs:7
Species:4         
Species With Barcodes:2         
          
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Barcode data

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Locations of barcode samples

Collection Sites: world map showing specimen collection locations for Mesoplodon

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Wikipedia

Gray's beaked whale

Gray's beaked whale!<-- This template has to be "warmed up" before it can be used, for some reason -->

Gray's Beaked Whale (Mesoplodon grayi), sometimes known as Haast's Beaked Whale, the Scamperdown Whale, or the Southern beaked whale, is one of the better-known members of the genus Mesoplodon. The scientific name refers to John Edward Gray, a zoologist at the British Museum. This species is fairly gregarious and strands relatively frequently for a beaked whale. It is notable for being the only beaked whale, other than Shepherd's Beaked Whale (not a Mesoplodon), that has numerous teeth.

Contents

Description

Gray's Beaked Whale is a fairly slender member of the genus. The melon on the whale bulges towards the blowhole and slopes down towards the beak. The beak itself is very long and pointed for a beaked whale, and has a relatively straight mouth line. In both sexes there are 17–22 rows of small teeth located towards the back of the mouth which barely protrude past the gum. In males, there are two small, triangular teeth present halfway down the mouth. The overall coloration is dark on top and light below, and both sexes have a white beak. Females are lighter on top and have additional white marking near the genitals. Adult males often carry linear scars that probably result from fighting, and both males and females may display circular scars from cookiecutter shark bites.[2] Females reach at least 5.3 meters (17 feet 6 inches) whereas males reach 5.7 meters (19 feet) and weigh around 1100 kilograms (2400 pounds). They are believed to be around 2.4 meters (7 feet 10 inches) long when born.

Behavior

An adult female, one of five Gray's beaked whales stranded at Port Waikato, New Zealand.

The Gray's beaked whale is very gregarious. It has a tendency to strand in large groups, once involving 20 individuals. Other strandings involved five to eight animals. The upper teeth may be used in holding prey, but it not clear why only this species has them.

Population and distribution

This species typically lives in the Southern Hemisphere between 30 and 45 degrees. Many strandings have occurred off New Zealand, but others have happened off Australia, South Africa, South America, and the Falkland Islands. This species has been sighted in groups off the coast of Madagascar and in the Antarctic area. Oddly, one specimen stranded off the Netherlands, on a different Hemisphere and several thousand miles away from all other strandings. No population estimates exist, but they are believed to be rather common.

Conservation

These whales have not been hunted deliberately and they have not been entangled in fishing gear.

Specimens

References

  1. ^ Taylor, B.L., Baird, R., Barlow, J., Dawson, S.M., Ford, J., Mead, J.G., Notarbartolo di Sciara, G., Wade, P. & Pitman, R.L. (2008). Mesoplodon grayi. In: IUCN 2008. IUCN Red List of Threatened Species. Downloaded on 24 March 2009. Database entry includes a brief justification of why this species is of data deficient.
  2. ^ Gray's Beaked Whale, Australian Museum. Updated 13 October 2009. Retrieved 13 January 2011.

Bibliography

  • Encyclopedia of Marine Mammals. Edited by William F. Perrin, Bernd Wursig, and J.G.M Thewissen. Academic Press, 2002. ISBN 0-12-551340-2
  • Sea Mammals of the World. Written by Randall R. Reeves, Brent S. Steward, Phillip J. Clapham, and James A. Owell. A & C Black, London, 2002. ISBN 0-7136-6334-0
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Mesoplodont whale

Mesoplodont whale!<-- This template has to be "warmed up" before it can be used, for some reason -->

Mesoplodont whales are fourteen species of whale in the genus Mesoplodon, making it the largest genus in the cetacean order. Two species were described as recently as 1991 (Pygmy Beaked Whale) and 2002 (Perrin's Beaked Whale), and marine biologists predict the discovery of more species in the future. They are the most poorly known group of large mammals. The word mesoplodon comes from the Greek meso- (middle) - hopla (arms) - odon (teeth), and may be translated as 'armed with a tooth in the centre of the jaw'.

Contents

Species

English name (most common first), Latin name:

Longman's Beaked Whale (also known as the Indo-Pacific Beaked Whale) is also sometimes classed in the Mesoplodon genus. However, all recent authorities follow the lead of Joseph Curtis Moore who in the 1960s put it in its own genus - Indopacetus.

Physical description

Beaked whales are typically medium- to large-sized for toothed whales, 3 to 6 meters in length, but diminutive when compared with Bottlenose Whales and Giant Beaked Whales. The females are the same size or larger than males in every species, but the males typically have a bolder coloration and a unique dentition. 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. Gray's Beaked Whale is the exception and has numerous small and possibly functional teeth in the lower jaw. The males of most species are covered in scars from the teeth of other males. Both sexes often have bites from cookie-cutter sharks. The dorsal fin is rather small and far between two-thirds and three-quarters down the back of the animal. Information on longevity and lactation is not existent, and information on gestation is nearly so.

Behavior

Most species are very rarely observed, and little is known about their behavior. They are typically found in groups, possibly segregated between sexes. Some species are so uncommon that they have yet to be observed alive. 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 either. They are all very deep divers, and typically 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 nets. It is not known what effect this has on the population.

References

  • Encyclopedia of Marine Mammals. Edited by William F. Perrin, Bernd Wursig, and J.G.M Thewissen. Academic Press, 2002.
  • Sea Mammals of the World. Written by Randall R. Reeves, Brent S. Steward, Phillip J. Clapham, and James A. Owell. A & C Black, London, 2002.
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