Dogfish Shark Skeleton Diagram Unlabeled

All 19 parts on the diagram

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Whole skeleton 9

Chondrocranium The braincase, one piece of cartilage with no seams. It encloses the brain.
Vertebral column The backbone, a row of cartilage vertebrae. It runs from the braincase to the tail.
Heterocercal tail The backbone bends up into the upper lobe. A tail built this way is called heterocercal.
Pectoral girdle A curved bar behind the gills. It carries the two pectoral fins.
Pectoral fin cartilages Cartilages at the base of the fin. Large basals come first, then rows of small radials.
Fin rays Slender flexible rays stiffen the outer part of each fin.
Pelvic girdle A short bar of cartilage across the belly. The two pelvic fins join it.
Dorsal fin cartilages A basal plate and a row of radials hold up each dorsal fin.
Fin spine A spine stands in front of each dorsal fin. It gives the spiny dogfish its name.

Head and gill arches 10

Rostrum The front of the braincase, drawn out like a trough. It supports the snout.
Nasal capsule A thin-walled capsule at the base of the rostrum. It holds the organ of smell.
Orbit The large hollow in the side of the braincase. It holds the eye.
Otic capsule The part of the braincase that holds the inner ear.
Upper jaw (palatoquadrate cartilage) The upper jaw. A ligament ties it to the braincase, and it carries teeth.
Lower jaw (Meckel's cartilage) The lower jaw. It meets the upper jaw at a hinge, the angle of the jaw.
Teeth Both jaws carry teeth.
Hyomandibular cartilage A stout piece between the ear region and the jaw hinge. It helps hang the jaws from the braincase.
Gill arches Bent bars of cartilage that support the gills. They are not joined to the backbone.
Gill rays Slender rods on the back edge of an arch. They hold the gills out.

How this list was compiled: Every name checked on 2026-10-02 in two sources. L. H. Hyman, A Laboratory Manual for Comparative Vertebrate Anatomy (1922, public domain), the chapters on the dogfish and its skeleton, https://archive.org/details/laboratorymanual00hyma. J. F. Daniel, The Elasmobranch Fishes (1922, public domain), the chapters on the skeleton, https://archive.org/details/bwb_KV-166-519. Wikipedia, Shark anatomy and Chondrocranium, https://en.wikipedia.org/wiki/Shark_anatomy. Licence: own work

The drawing: Drawn for this site on 2026-10-02 from plain geometry; nothing traced. Licence: own work

How it works

A dogfish shark skeleton diagram, unlabeled: the whole skeleton of a spiny dogfish from the left side, and under it the head enlarged. Every line is left empty, nine on the whole fish and ten on the head.

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The nineteen names

Whole skeleton: chondrocranium, vertebral column, heterocercal tail, pectoral girdle, pectoral fin cartilages, fin rays, pelvic girdle, dorsal fin cartilages, fin spine. Head: rostrum, nasal capsule, orbit, otic capsule, upper jaw, lower jaw, teeth, hyomandibular cartilage, gill arches, gill rays.

Lines that end close together

At the first dorsal fin, one line ends on the spike that stands in front and the other on the blocks at the base of the fin. At the pectoral fin, the blocks at its base are the fin cartilages and the fine stripes beyond them the fin rays. On the head, the gill arches are the bent bars and the gill rays the short rods behind them.

The long bar standing apart at the rear of the head drawing is the pectoral girdle again, not a gill arch. It has no line.
A lab manual may print olfactory capsule for the nasal capsule, auditory capsule for the otic capsule and branchial arches for the gill arches.

Questions and answers

How many gill arches does a dogfish shark have?

Seven, as a comparative anatomy manual counts them. The jaws are the first, and the hyomandibular cartilage belongs to the second. The five bent bars behind are what this sheet calls gill arches; the last carries no gill rays.

What is left off this unlabeled dogfish shark skeleton?

The claspers of a male, the ceratohyal, the basals and radials of each fin by name, and the small arches above and below the backbone. All but the claspers are drawn, but none has a line.

What is the pectoral girdle of a dogfish shark?

A curved cartilage that reaches almost all the way round the body just behind the gills. The part between the two pectoral fins is the coracoid bar, and the arms that run up the sides are the scapular processes.

Does the unlabeled dogfish skeleton come with an answer key?

Yes. The key is the same sheet with each of the nineteen names at the end of its line. The jaws carry two names each: upper jaw (palatoquadrate cartilage) and lower jaw (Meckel's cartilage).