Vertebrate Zoo L4: Lamprey
- Created by: ValentineDevil
- Created on: 05-02-19 00:37
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- The Lamprey
- General features
- Mostly freshwater; some marine
- Some parasitic, mostly scavenger
- Funnel mouth with concentric rings
- Several inches to a metre long
- Scale-less skin
- Jaw-less; bone-less; no-paired fins' 2 dorsal fins
- Fin number/ position
- Blood and flesh feeders
- Morphology of the mouth and arrangement of teeth related to feeding strategy
- Adaptive immune system as in jawed vertebrates
- Highest chromosome number among vertebrates in the Northern lamprey
- Some species tolerant of free iron
- Other characteristics of lamprey
- Larval stage + metamorphosis
- Slightly elaborate skulls
- Brain
- Poorly developed cerebellum
- Large optic lobes
- NO intrinsic eye muscles
- Brain
- Single small dorsal nostril
- Nasal duct ends in blind pouch
- Protrusible tooth-covered tongue
- Vertebrae consisting of simple dorsal elements
- Buccal funnel armed with teeth
- 7 pairs of external gill slits arranged along a slanting line
- Atrium and ventricle closely set
- Adult heart with nervous regulation
- Neuromasts of lateral line system
- Left and right gonads are fused up
- Gill-based blood osmoregulation
- Subdivided pharynx
- Key points
- Opening of nostril
- Extent of hypophyseal complex
- Position of olfactory sac
- Near nostril opening (round mass, small)
- Location/shape of tongue
- Protrusible tooth-covered tongue
- Buccal funnel armed with teeth
- Cartilages/ muscles of tongue
- Protractor then retractor behind it along the lamprey length
- Gill openings (external and internal)
- 7 pairs of external gill slits arranged along a slanting line
- Mouth shape
- Funnel mouth with concentric rings
- Fin number/ position
- Skeleton key points
- Mostly situated in the head, and trunk region
- Mostly slender cartilaginous elements (arches like dorsal vertebrae)
- Cartilages support oral cone,, nasohypoyseal, tongue and heart
- Brachial basket
- Slightly elaborate braincase contributing to nasal and auditory capsules, with interposed cartilages between capsules
- Slender rays in the caudal fin (ALSO FOUND IN HAGFISH!)
- Feeding mechanism
- Attaches to prey using buccal funnel (oral cone)- suction created
- Suction: constriction of annular musculature = narrowing of funnel
- Aided by passive elastic recoiling of brachial basket
- Activates protractor musculature = lingual cartilage pulled forward (moved outward and downward like a conveyor belt)
- Salivary glands secrete anticoagulant
- Retractor muscle (mretr) fibres pull the tongue inward and upward while the piston-like cartilage (pistc) is pulled back
- Ensures scraping action of tongue (chunks of flesh ripped off and ingested via suction of fluids (suction via inhaled H2O current moving through gills)
- Velum ensures H2O currents carrying food particles are conveyed towards the oesphagus.
- Lamprey can breathe while feeding
- Suction: constriction of annular musculature = narrowing of funnel
- Attaches to prey using buccal funnel (oral cone)- suction created
- General features
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