Subphylum Vertebrata

Vertebrata (L., vertebratus = having joints, from vertebra = vertebra, from vertere = to turn or bend. This probably refers to the vertebrae wrapping around the spinal cord. )

Important features of the group:

The subphylum Vertebrata is probably the most recent group of chordates to evolve. All vertebrates have, at some point in their lives, the four chordate characteristics mentioned above. In addition, vertebrates possess the following:

The earliest vertebrates in the fossil record fall into three groups: the ostracoderms, acanthodians, and placoderms. The first of these groups, the ostracoderms, were armored jawless fish; they lacked any biting or chewing mechanism. The ostracoderms had bony plates that covered their body surface. The early ostracoderms are thought to have been sluggish creatures, and lacked paired appendages for maneuvering, so the plates probably served as protective armor against the attacks of large invertebrate predators. It is now known that ostracoderms date from the Cambrian and were abundant through the early part of the Paleozoic era. One lineage of ostracoderms is thought to have given rise to a jawed fish, which in turn gave rise to a number of different lineages of jawed fishes. The two oldest groups of jawed fish were the acanthodians and placoderms. Both of these groups were abundant through the middle and later parts of the Paleozoic era.

Human spine. Five lumbar bones are found in the lower back, with those here being: L1 (at top) to L4 (at bottom). Part of L5, which articulates with the sacrum of the pelvis, is seen below L4. The lumbar vertebrae are the largest of the unfused vertebrae in the backbone. Each vertebra comprises a wide disc-like body, with transverse bony processes projecting out sideways. These bony processes are muscle attachment points. Between each vertebra is a cartilaginous disc. A canal inside each vertebra accommodates the spinal cord. The spine is made up of 33 vertebrae. Photo credit:  Ali Pivoda

Vertebrate phylogeny. Major groups of extant vertebrates are included. Shared derived characters of each group are indicated in the orange boxes. (From Campbell 6th edition's Fig 34.7.)

The placoderm Dunkleosteus. reaching 30' in length, Dunkleosteus was a top predator of its day. Note the bony protrusions hanging down from the upper jaw, these are not homologous to teeth but probably functioned similarly.

Examples:

The subphylum Vertebrata includes many classes, those most pertinent to the Deuterostomes lab are shown below.

Examples of each class are shown at right. For more detailed information on each group follow the links above.

Class Cephalaspidomorphi

Sea lamprey (Petromyzon marinus) showing its circumoral teeth in its jawless mouth. Credit: Ali Pivoda

Class Chondrichthyes

Cownose ray. The ray is a fish that lacks true bones. Like the related shark, it has a skeleton composed of cartilage. This ray can reach about 120 centimeters in width. It uses its broad "wings" to swim through its ocean environment. It feeds on shellfish, which it crushes using its powerful mouth. Its long tail has a poisonous sting that is used for defense. The gills, which extract oxygen from the water, form two rows behind the mouth. The eyes are either side of the notched head hump. This ray, found in the tropical Atlantic Ocean, gives birth to live young.  See a preserved specimen of a baby cownose ray in the Biology Study center (Thanks Dr. McFadden)!

Class Osteichthyes

Perca flavis, the common perch. Photo credit: Ali Pivoda

Class Amphibia

Green frog in High Tor Wildlife Management Area, Naples, NY

Reptiles

Brown anole (Anolis sagrei).  A lizard native to Cuba.

Reptiles

Carapace of turtle.  The upper shell is largely made of bone and so is a living structure.  The vertebrae and ribs of the turtle expand and fuse with other bones to form the carapace.  There are also  plates of keratin on the outside of the shell which overlap two or more bones of the shell, locking them together.

Birds

Great blue heron (Ardea herodias)

Class Mammalia

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