Rostrum (anatomy) From Wikipedia, the free encyclopedia

The rostrum (beak) of a bottlenose dolphin In anatomy, the term rostrum (from the Latin rostrum meaning beak) is used for a number of phylogenetically unrelated structures in different groups of animals.

Contents [hide] 1 Invertebrates 2 Vertebrates 3 Anatomy 4 See also 5 References Invertebrates[edit | edit source] In crustaceans, the rostrum is the forward extension of the carapace in front of the eyes.[1] It is generally a rigid structure, but can be connected by a hinged joint, as seen in Leptostraca.[2] Among insects, the rostrum is the name for the piercing mouthparts of the order Hemiptera. The long snout of weevils may also be called a rostrum.[3] Gastropod molluscs have a rostrum or proboscis.[4] Cephalopod molluscs have hard beak-like mouthparts referred to as the rostrum.[5] Invertebrate rostrums

Crustacean: the rostrum of the shrimp Macrobrachium rosenbergii is serrated along both edges.

Insect: assassin bug piercing its prey with its rostrum

Cephalopod: the two-part beak of a giant squid Vertebrates[edit | edit source] The beak or snout of a vertebrate may also be referred to as the rostrum.

Some cetaceans, including toothed whales such as dolphins[6] and beaked whales, have rostrums (beaks) which evolved from their jawbones. The narwhal possesses a large rostrum (tusk) which evolved from a protruding canine tooth. Some fish have permanently protruding rostrums which evolved from their upper jawbones. Billfish (marlin, swordfish and sailfish) use rostrums (bills) to slash and stun prey. Paddlefish, goblin sharks and hammerhead sharks have rostrums packed with electroreceptors which signal the presence of prey by detecting weak electrical fields. Sawsharks and the critically endangered sawfish have rostrums (saws) which are both electro-sensitive and used for slashing.[7] The rostrums extend ventrally in front of the fish. In the case of hammerheads the rostrum (hammer) extends both ventrally and laterally (sideways). Anatomy The anatomy of a shark rostrum is that it is the pointed protrusion at the cranial end of the fish. The rostrum has a rostral carina that runs up the middle of it. On both side of the Rostrum lie important structures. These include the nasal capsules and the rostral fenestrae. [8] The upper jawbones of some fish have evolved into rostrums

Sailfish, like all billfish, have a rostrum (bill) which is an extension of their upper jawbone

The paddlefish has a rostrum packed with electroreceptors

Sawfish have an electro-sensitive rostrum (saw) which is also used to slash at prey

Hammerheads use their rostrum (hammer) to detect and pin rays buried in sand See also[edit | edit source] Beak Nostril References[edit | edit source] Jump up ^ Charles Drew (November 17, 2003). "Crustacea". University of Bristol. Retrieved November 7, 2010. Jump up ^ Todd A. Haney, Joel W. Martin & Eric W. Vetter (2007). "Leptostraca". In James T. Carlton. The Light and Smith Manual: Intertidal Invertebrates from Central California to Oregon (4th ed.). University of California Press. pp. 484–495. ISBN 978-0-520-23939-5. Jump up ^ George Gordh, Gordon Gordh & David Headrick (2003). "Rostrum". A Dictionary of Entomology. CAB International. p. 792. ISBN 978-0-85199-655-4. Jump up ^ Douglas Grant Smith (2001). "Mollusca (gastropods, pelecypods)". Pennak's freshwater invertebrates of the United States: Porifera to Crustacea (4th ed.). John Wiley and Sons. pp. 327–400. ISBN 978-0-471-35837-4. Jump up ^ Burt Carter. "Cephalopods". Invertebrate Paleobiology. Jump up ^ "Basic anatomy of Cetaceans - Dolphins". Robin's Island. Retrieved November 7, 2010. Jump up ^ Wueringer BE, Squire Jr L, Kajiura SM, Hart NS and Collin SP (2012) "The function of the sawfish's saw" Current Biology, 22 (5): R150-R151. doi:10.1016/j.cub.2012.01.055 Jump up ^Kenneth V. Kardong, Edward J. Zalisko. "Comparative Vertebrate Anatomy". McGraw Hill Education. 2015

Project Preferences

1. Iguana

https://en.wikipedia.org/wiki/Iguana

I am most interested in doing my project on an iguana because I feel this is not a typical specimen that one gets to dissect. I think that there is a lot that can be learned from dissecting the iguana and I am interested to see how it would be to dissect a very spiny, scaly creature.

Possible Edits The Anatomy section of the Iguana Page is really all there is and still there is very little information. It highlights about three features of the iguanas anatomy and i think this could be covered in more depth especially after the project.

3.Microbat

https://en.wikipedia.org/wiki/Talk:Microbat

I would be interested in studying the micro bat because of its use of echolocation through its Pharynx, i find this to be a fascinating feature that I would like to learn more about.

Possible Edits The intro to this page isn't necessarily about the micro bat but instead illuminates what a micro bat no longer is, i think this should be changed. Also it lacks a real anatomy?physiology section.

2.Amia

https://en.wikipedia.org/wiki/Bowfin

I would be interested in doing my project on the Bowfin because they are the only descendent of a group which dates back to Jurassic times.

Possible Edits Multimodal distribution page is lacking and is a huge part of how the bowfin breathe. https://en.wikipedia.org/wiki/Multimodal_distribution Hypoxia would be an interesting page to do some research on. https://en.wikipedia.org/wiki/Talk:Hypoxia_(environmental)

— Preceding unsigned comment added by Terhaaed (talk • contribs) 19:50, 1 March 2017 (UTC)

Bowfin Article: Possible Edits

Actinopterygii

This article is labeled as a start and has very little information.

Physostome

This article is only a stub. Only has one reference. Bowfins are Physostomes, so adding more information to this page would be beneficial to the Bowfin page.

Hypoxia

This article is rated as a start, and only has 10 references. This is how Bowfin are able to exchange age so it would be valid to know.

http://web.b.ebscohost.com.ezproxy.plu.edu/ehost/pdfviewer/pdfviewer?sid=6a8cf914-e42f-4599-8b5a-b3ae2b397ad5%40sessionmgr101&vid=1&hid=124

In general the morphology/physiology section of the Bowfin page is lacking quite a bit. I think from what is in our textbooks there could be quite a bit of information added. I also think that our dissection will be helpful in adding to this section.
Page 71 has a good deal about the skull of the Bowfin and the cranial layers...chondrocranium and dermatocranium.
page 46 shows the axial skeleton
page 62 shows the pectoral girdle and the appendages.
page 45 shows the ribs

~~~~terhaaed

Morphology Edits to Bowfin Page

The average length of a bowfin is 50 cm (20 in); females typically grow to 65–70 cm (26–28 in), males to 50–65 cm (20–26 in). Records indicate bowfin can reach 109 cm (43 in) in length, and weigh 9.75 kg (21.5 lb). Young of the year typically grow to 13–23 cm (5.1–9.1 in) by October. Females tend to grow larger than males. Diagram showing fins and eyespot of a bowfin. USFW&S The body of the bowfin is elongated and cylindrical, with the sides and back olive to brown in color, often with vertical bars, and dark reticulations, or camouflaged pattern. The dorsal fin has horizontal bars, and the caudal fin has irregular vertical bars. The underside is white or cream, and the paired fins and anal fin are bright green. During larval stage, hatchlings from about 7–10 mm (0.28–0.39 in) total length are black and tadpole-like in appearance. At approximately 25 mm (0.98 in) total length they have been described as looking like miniature placoderms. They grow quickly, and typically leave the nest within 4 to 6 weeks after hatching. Young males have a black eyespot on the base of the tail (caudal peduncle) that is commonly encircled by an orange-yellowish border while the female's is black, if present at all. It is thought the purpose of the eyespot is to confuse predators, deflecting attacks away from the head of the fish to its tail, which affords the bowfin an opportunity to escape predation. The bowfin is so named for its long, undulating dorsal fin consisting of 145 to 250 rays, and running from the middle of the back to the base of the tail.

The skull of the bowfin is made of two layers of skull, the dermatocranium and the chondrocranium. The chondrocranium layer cannot be seen because it is located below the dermal bones. The bowfin skull is made up of 28 fused bones, which compose the dermatocranium. The roof of the mouth is made up of 3 bones, the ectopterygoid, the palantine, and the vomer. The teeth are on two bones, the pre maxillae and the maxillae. Another three bones make up the lower jaw the dentary, the angular, and the surangular. The cranial suface of the skull is made up of the nasals, the antorbital, the lacrimal, the parietal, the inter temporal, the post parietal, the suptratemporal, the extra scapular, the post temporal, and the opercular. The entirety of the skull is attached to the girdle through another set of bones.

The post cranial elements of the bowfin skelton consist of the vertebrae and the girdles. Drawing of a bowfin skull showing the bony plates protecting the head Bowfin are often referred to as "living fossils", or "primitive fishes" because they retained some of the primitive characters common to their ancestral predecessors, including a modified (rounded externally) heterocercal caudal fin, a highly vascularized gas bladder lung, vestiges of a spiral valve, and a bony gular plate. The bony gular plate is located underneath the head on the exterior of the lower jaw between the two sides of the lower jaw bone. Other distinguishing characteristics include long, sharp teeth, and two protruding tube-like nostrils.Unlike all of the most primitive actinopterygians, the scales of bowfin differ in that they are not ganoid scales, rather they are large, single-layered cycloid scales closer in similarity to more derived teleosts.

Edits to the Chondrocranium Page

The chondrocranium (or cartilaginous neurocranium) is the primitive cartilaginous skeletal structure of the fetal skull that grows to envelop the rapidly growing embryonic brain. The main job of this layer is to encase the sensory organs.

The chondrocranium in different species can vary greatly , but in general it is made up of five components, the sphenoids, the mesethmoid, the occipitals, the optic capsules, and the nasal capsule.

In humans, the chondrocranium begins forming at 28 days from mesenchymal condensations and is fully formed between week 7 and 9 of fetal development. While the majority of the chondrocranium is succeeded by the bony skull in most higher vertebrates, some components do persist into adulthood. In cartilaginous fishes (e.g. sharks and rays) and agnathans (e.g. lampreys and hagfish), the chondrocranium persists throughout life. Embryologically, the chondrocranium represents the basal cranial structure, and lays the base for the formation of the endocranium in higher vertebrates.