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Names for undescribed species
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Remove species info as on species pages where more appropriate, whaler → requiem
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{{Taxobox
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{{Sharksportal}}
{{Sharksportal}}
The '''river sharks''' are six rare species of [[shark]] in the [[genus]] '''''Glyphis'''''. The river sharks are members of the family [[Carcharhinidae]], and thus share the basic characteristics of the group. Note: the [[Bull shark]] is sometimes called both the river shark and the Ganges shark; it should not be confused with the true river sharks of ''Glyphis''.
The '''river sharks''' are six (three to be formally described) rare species of [[shark]] in the [[genus]] '''''Glyphis''''', although, due to their secretive habits, other species could easily remain undiscovered. The river sharks are members of the family [[Carcharhinidae]], and thus share the basic characteristics of the group. Note: the [[bull shark]] is sometimes called both the river shark and the Ganges shark; it should not be confused with the true river sharks of ''Glyphis''.


==Characteristics==
==Characteristics==
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==Morphology==
==Morphology==
River sharks are very similar in overall morphology to [[whaler shark]]s of the genus [[Carcharhinus]], but can be distinguished from them by the following characteristics:
River sharks are very similar in overall morphology to [[requiem shark]]s of the genus [[Carcharhinus]], but can be distinguished from them by the following characteristics:

* cusps of lower teeth protrude prominently when mouth is closed;
* cusps of lower teeth protrude prominently when mouth is closed;
* second [[dorsal fin]] is 1/2 to 3/5 the height of the first [[dorsal fin]];
* the second [[dorsal fin]] is 1/2 to 3/5 the height of the first [[dorsal fin]];
* origin of second dorsal fin slightly anterior to origin of [[anal fin]];
* the origin of the second dorsal fin is slightly anterior to the origin of the [[anal fin]];
* [[precaudal pit]] is longitudinal rather than crescent-shaped.
* [[precaudal pit]] is longitudinal rather than crescent-shaped.


==Species==
==Species==
Six [[species]] of river sharks are known, although due to their secretive habits, other species could easily be undiscovered.

'''Asia'''
* [[Ganges shark]], ''[[Glyphis gangeticus]]'' <small>([[Johannes Peter Müller|Müller]] & [[Friedrich Gustav Jakob Henle|Henle]], 1839)</small>
* [[Ganges shark]], ''[[Glyphis gangeticus]]'' <small>([[Johannes Peter Müller|Müller]] & [[Friedrich Gustav Jakob Henle|Henle]], 1839)</small>
*: Definitely known from the [[Ganges river|Hooghly-Ganges river system]], [[West Bengal]], [[India]], and likely from the vicinity of [[Karachi]], [[Pakistan]].

'''Oceania'''
* [[Speartooth shark]], ''[[Glyphis glyphis]]'' <small>([[Johannes Peter Müller|Müller]] & [[Friedrich Gustav Jakob Henle|Henle]], 1839)</small>
* [[Speartooth shark]], ''[[Glyphis glyphis]]'' <small>([[Johannes Peter Müller|Müller]] & [[Friedrich Gustav Jakob Henle|Henle]], 1839)</small>
*: Uncertain. Speartooth-like sharks occur in [[Borneo]], [[New Guinea]], and [[Queensland]], [[Australia]], but it is uncertain at present if any of these are the true ''G. glyphis''. The [[holotype]] has no capture locality listed for it.
* [[Irrawaddy River shark]], ''[[Glyphis siamensis]]'' <small>([[Franz Steindachner|Steindachner]], 1896)</small>
* [[Irrawaddy River shark]], ''[[Glyphis siamensis]]'' <small>([[Franz Steindachner|Steindachner]], 1896)</small>
*: The only known specimen is from the [[Ayeyarwady River]], near [[Yangon]] (Rangoon). Until very recently, this species was regarded as an aberrant specimen and possible [[synonym]] of (the same species as) the [[bull shark]], but shark systematist [[Leonard J.V. Compagno]] now considers it a member of the genus ''Glyphis'', distinct from the other known species.
* [[Bizant river shark]], ''[[Glyphis sp. A]]'', not yet described.
* [[Bizant river shark]], ''[[Glyphis sp. A]]'', not yet described.
*: Known from two specimens from estuarine waters of the lower reaches of the [[Bizant River]] in [[Queensland]], [[Australia]], where it occurs along with the bull shark. It is also known from the [[Alligator River]] system of the [[Northern Territory]], where it occurs with ''Glyphis'' species C. Intriguingly, ''Glyphis'' specimens from the [[Adelaide River]], Northern Territory, that have provisionally been identified as this species display very different vertebral counts (148 total [[vertebrae]], versus 217 in specimens from the Bizant River).
* [[Borneo river shark]], ''[[Glyphis sp. B]]'', not yet described.
* [[Borneo river shark]], ''[[Glyphis sp. B]]'', not yet described.
*: Known from a single specimen from [[Borneo]]. Recently, several small ''Glyphis'' have been collected from the [[Kinabatangan River]] of [[Sabah]], in northern Borneo. These may be the same species as Glyphis species B. The species is presently in the process of being described by [[Sarah Fowler]] and [[Leonard J.V. Compagno]].
* [[New Guinea river shark]], ''[[Glyphis sp. C]]'', not yet described.
* [[New Guinea river shark]], ''[[Glyphis sp. C]]'', not yet described.
*: Only nine specimens have ever been collected — an immature female taken about 100 km up the [[Adelaide River]] in [[1989]], an adult male taken some 60 km up the [[South Alligator River]] in [[1996]], and in [[1999]], five females and two males from the East, West and South Alligator Rivers, in [[brackish]] water, with [[salinity]] ranging from 6 to 26 ppt. This species also occurs alongside ''Glyphis'' species A.


==References==
==References==

Revision as of 09:03, 31 October 2006

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River sharks
Scientific classification
Kingdom:
Animalia
Phylum:
Chordata
Class:
Chondrichthyes
Subclass:
Elasmobranchii
Order:
Carcharhiniformes
Family:
Carcharhinidae
Genus:
Glyphis

Agassiz, 1843
Species

See text

Template:Sharksportal The river sharks are six (three to be formally described) rare species of shark in the genus Glyphis, although, due to their secretive habits, other species could easily remain undiscovered. The river sharks are members of the family Carcharhinidae, and thus share the basic characteristics of the group. Note: the bull shark is sometimes called both the river shark and the Ganges shark; it should not be confused with the true river sharks of Glyphis.

Characteristics

In general, all river sharks feature the following field characteristics:

  • a short, broadly rounded snout (its length less than the mouth width);
  • small, widely spaced nostrils;
  • small, dark eyes;
  • broad, serrated upper teeth;
  • very short labial furrows (lip grooves), restricted to the jaw corners;
  • a broad dorsal fin with the mid-base closer to the base of the pectoral fins than those of the pelvic fins; and
  • an anal fin with a deeply excised posterior margin.

Morphology

River sharks are very similar in overall morphology to requiem sharks of the genus Carcharhinus, but can be distinguished from them by the following characteristics:

  • cusps of lower teeth protrude prominently when mouth is closed;
  • the second dorsal fin is 1/2 to 3/5 the height of the first dorsal fin;
  • the origin of the second dorsal fin is slightly anterior to the origin of the anal fin;
  • precaudal pit is longitudinal rather than crescent-shaped.

Species

References

  • "Glyphis". Integrated Taxonomic Information System. 4 May. {{cite web}}: Check date values in: |date= and |year= / |date= mismatch (help)
  • Northern Speartooth Shark - Glyphis sp. C
  • Compagno, Dando, & Fowler, Sharks of the World, Princeton University Press, New Jersey 2005 ISBN 0-691-12072-2

See also

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