Bahamas sawshark

Source: Wikipedia, the free encyclopedia.

Bahamas sawshark

Least Concern  (IUCN 3.1)[1]
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Subdivision: Selachimorpha
Order: Pristiophoriformes
Family: Pristiophoridae
Genus: Pristiophorus
Species:
P. schroederi
Binomial name
Pristiophorus schroederi
Range of Bahamas sawshark (in blue)

The Bahamas sawshark, Pristiophorus schroederi, is a

Bahamas and Cuba
at depths of between 400 and 1,000 m. These sharks are at least 80 cm long.

The Bahamas sawshark is found on

ovoviviparous
.

Pristiophorus schroederi is the first member of the

Little Bahama Bank.[2]

Behavior

Despite the menacing appearance of this sawshark, it tends to feed primarily on

crustaceans like other species of its kind.[4] They feed primarily on the seafloor.[4] Although most shark species tend to spend most of their time solitary, sawsharks are known to form schools.[5]

Ecology

Many members of the family Pristiophoridae are endangered, including the P. schroederi. The sawsharks in general are among the most threatened

sharks on the planet.[4]

Phylogeny

Springer and Bullis (1960) began to explore the possibility of only one extant Pristiophorus species worldwide, but failed to legitimize that statement due to several distinct species in our seas, one of those species being P. schroederi. The farthest lineage known goes back to early

Cretaceous period, but this species (P. tumidens) is considered an offshoot of the main Pristiophorid lineage.[3]

Anatomy

Sharks in the sawshark family (Pristiophoridae) are similar to the sawfish (family Pristidae) in their saw-like snout, but are smaller and have the basic structural plan of sharks rather than rays. Distinguishing features include a slight compression of their body and strong flattening of their head, and they tend to reach maturity at around one meter.[2]

Head

Pristiophorus schroederi has a flattened head, which is typical of this family. It has five

barbels located on either side of the snout. The mouth itself is slightly arched.[2]

The upper jaw teeth are in 36 rows and the bottom jaw teeth are shaped similarly but in 32 rows.[6] P. nudipinnis is within the same range as P. schroederi.[6] The eyes are large in comparison to overall size, about two times the size horizontally compared to vertically.[2] It is hard to establish any outrageous differences between the P. schroederi and other species of sawsharks, although the P. schroederi do tend to have a proportionately longer snout than other species.[2] Notably longer than the snout of P. owenii and P. nudipinnis but only a little bit longer than that of P. cirratus.[2] As for teeth (P. schroederi with 33 to 36 rows) is different from P. cirratus and P. japonicas with 39 to 56 rows.[6] P. nudipinnis is within the same range as P. schroederi.[6]

Body

It has no

pelvic fins.[2] It has large pectoral fins, that's inner margins curve inward toward the base of the fins.[2]
There are
dermal denticles on the dorsal surface of the body with very little overlapping.[5] Fins are fully scaled but the snout is only partially covered.[5] The ventral scales are usually leaf like with no accessory points or ridges. P. nudipinnis shows the largest difference in denticle structures.[2] P. schroederi has typical denticles of the dorsal surface that are usually slender and leaf like, they bear a very long slender point directed up and back with two accessory points on either side.[2] The dorsal dermal denticles of P. nudipinnis are thickened and broader rather than longer.[2] They are about diamond-shaped, and paved.[7] The 3-point denticles distinguish P. schroederi very apparently from all other species of Pristiophorus.[7]

References

  1. IUCN: e.T60226A124453528. Retrieved 20 January 2021.{{cite journal}}: CS1 maint: multiple names: authors list (link
    )
  2. ^ a b c d e f g h i j k l m n Springer, Stewart, and Harvey R. Bullis, Jr. "A New Species of Sawshark, Pristiophorus Schroederi, From the Bahamas." Bulletin of Marine Science 10.2 (1960): 241-54. Ingentaconnect. Web. May 31, 2013.
  3. ^ a b c Keyes, W. I. "The Cenozoic Sawshark Pristiophorus Lanceolatus (Davis) (Order Selachii) of New Zealand and Australia, with a Review of the Phylogeny and Distribution of World Fossil and Extant Pristiophoridae." New Zealand Journal of Geology and Geophysics 25.4 (1982): 459-74. ProQuest. Web. 2 June 2013.
  4. ^ a b c Look, A. Closer. "The Evolution of Shark Dentition." Colostate.edu
  5. ^ a b c Klein, Adam G. Common Sawsharks. Checkerboard Books, 2005
  6. ^ a b c d Slaughter, Bob H., and Stewart Springer. "Replacement of Rostral Teeth in Sawfishes and Sawsharks." Copeia 1968.3 (1968): 499-506. Web. 2 June 2013.
  7. ^ a b Ebert, David A., and Gregor M. Cailliet. Bulletin of Marine Science 87.3 (2011): 501-12. Ingentaconnect. Web. 2 June 2013.

External links

Retrieved from "https://en.wikipedia.org/w/index.php?title=Bahamas_sawshark&oldid=1214744402"