Q.93 Lamprey, a jawless fish, belongs to which one of the following ‘Classes’?
(A) Myxini (B) Cephalaspilomorphi
(C) Conodonta (D) Anaspida
Lampreys belong to the class Cephalaspidomorphi (also called Hyperoartia or Petromyzontida in modern taxonomy), the living jawless vertebrates alongside hagfish.
This class distinguishes them from extinct armored jawless fish groups.
Correct Answer
(B) Cephalaspidomorphi
Option Analysis
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(A) Myxini: Class Myxini contains hagfish only—slimy, scavenging jawless fish lacking true vertebrae, vertebrae, or paired fins. Lampreys have cartilaginous vertebrae and differ in life cycle/development.
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(B) Cephalaspidomorphi: Modern lampreys (Petromyzontiformes/Petromyzontida) are the sole surviving members of this class, named for fossil Cephalaspis relatives. They feature a round suctorial mouth, single nostril, and 7-11 gill pouches.
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(C) Conodonta: Conodonta refers to extinct Cambrian-Devonian microfossils with mineralized “teeth,” now classified as chordates but not a living fish class. No relation to extant lampreys.
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(D) Anaspida: Extinct Ordovician-Devonian jawless fish with thin armor plating and elongated bodies; not modern lampreys, which lack such scales.
Lamprey Taxonomy Overview
Phylum Chordata → Subphylum Vertebrata → Infraphylum Agnatha → Class Cephalaspidomorphi → Order Petromyzontiformes → Family Petromyzontidae. ~50 extant species; anadromous life cycle.
Lamprey Jawless Fish Class: Cephalaspidomorphi Taxonomy
The lamprey jawless fish class Cephalaspidomorphi represents living agnathans. These primitive vertebrates feature cartilaginous skeletons, rasping disc mouths for parasitic feeding, and migratory breeding.
Classes Compared
| Option | Group Type | Key Features | Lamprey Match? |
|---|---|---|---|
| Cephalaspidomorphi | Living class | Jawless, vertebrae, 7 gill slits | Yes |
| Myxini | Hagfish class | No vertebrae, slime glands | No |
| Conodonta | Extinct microfossils | Tooth-like elements | No |
| Anaspida | Extinct armored fish | Scale-covered | No |
Lamprey jawless fish class Cephalaspidomorphi essential for GATE Life Sciences chordate evolution. Invasive sea lampreys (Petromyzon marinus) impact fisheries.
GATE Prep Insights
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Agnatha: Jawless (lampreys + hagfish).
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Synapomorphies: Single semicircular canal, pouch-like fins.
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Test focus: Living representative classification.
