Ch 8 vert zoo - digital summery

The Shrinking Waterhole Hypothesis

Suggests that limbs and lungs evolved to find new water sources as old ones dried up.

The Inter-Tidal Hypothesis

Proposes that sarcopterygians emerged from intertidal zones rather than inland pools.

The Woodland Hypothesis

Suggests limbs developed in shallow, wooded bodies of water for navigation among roots and vegetation.

Key anatomical changes in shallow-water habitats

Transitions likely evolved in shallow conditions, including limbs with digits and the development of necks.

Choanae

Internal nostrils that open between the nasal cavity and the nasopharynx.

'One-Bone, Two-Bone' Limb Pattern

The limb structure of tetrapodomorphs consisting of a single proximal bone, two bones, and digits.

Labyrinthodont teeth

Teeth characterized by complex infolded enamel and dentin found in early tetrapods.

Eusthenopteron

A Mid-Late Devonian lobe-finned fish with key features linked to early tetrapods.

Panderichthys

A 'fishapod' known for its flat, tetrapod-like body and skull with upward-facing eyes.

Tiktaalik roseae

A crucial transitional fossil with both fish-like and tetrapod-like traits, bridging the gap between fish and early tetrapods.

Acanthostega

One of the oldest known tetrapods, featuring robust limbs and eight digits.

Ichthyostega

An early tetrapod with distinct seven digits, still largely adapted for swimming.