They find a species of shark capable of walking

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A newly discovered

that breaks all the rules for survival is the focus of a study by

and collaborators in Australia.

They investigated how walking and swimming changes in the early development of the

(Hemiscyllium ocellatum).

This small

(about one meter) reef-dwelling

.

Found within the reefs around South Australia's Great Barrier Reef, epaulet sharks experience short periods of elevated CO2 and hypoxia (low oxygen) as well as

as the reefs become isolated with the outgoing tide.

Remarkably, this

is capable of surviving complete anoxia (without oxygen) for two hours without ill effects and at a much higher temperature than most other

.

The epaulet shark's ability to move efficiently between microhabitats in these challenging environmental conditions could directly affect

and physiological responses to climate change.

However, very few studies have examined

(body movements).

Those that have, only focus on stages of adult life.

No study has specifically examined their locomotion during early life, until now.

Since

may be key to epaulet sharks' robust response to challenging environmental conditions, FAU researchers, in collaboration with James Cook University and Australia's Macquarie University,

THE NEWBORNS

Newborns retain

through an internalized yolk sac, resulting in a bulging womb.

In contrast, juveniles are slimmer because they actively seek out

.

During development, the yolk that newborn sharks store begins to diminish as they become young.

As the yolk is depleted, the

Due to the

, the researchers expected to see differences in the locomotor performance of these walking sharks.

To test their hypothesis, they examined the

and juveniles during the three aquatic gait modes they use (slow-to-medium walking, fast walking, and swimming) using 13 anatomical landmarks along

.

They quantified axial body kinematics (velocity, amplitude, and frequency of tail flapping, and body curvature) and

bending , fin rotation, and duty factor and tail kinematics.

Surprisingly, results published in the

showed that differences in body shape did not alter kinematics between newborn and juvenile walking sharks.

Overall speed, fin rotation,

tail-beat frequency and amplitude were consistent between early life stages.

The data suggest that

are maintained among neonate and juvenile epaulet sharks, even when their feeding strategy changes.

These findings suggest that submerged locomotion in

by the yolk sac and the effects it has on body shape, as all aspects of submerged locomotion were comparable to those in the young.

"Studying

locomotion allows us to understand the ability of this species, and perhaps related species, to move in and out of the challenging conditions of their habitats," said

, lead author and associate professor at the Department of Biological Sciences of the FAU.

"Overall, these locomotor traits are key to the

that maneuvers in small reef crevices to avoid aerial and aquatic predators. These traits may also be related to its sustained

under challenging environmental conditions, including associated with climate change, an important topic for future studies.

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