Creature Column

The jellyfish Clytia hemisphaerica has long been established as a model for studying embryogenesis and gametogenesis because of its transparency, simple tissue architecture and evolutionary position. With the recent development of efficient transgenesis, this jellyfish is now poised for tackling systems-level questions in comparative neuroscience and regeneration.

The ascidian tunicate Ciona, one of the closest relatives of the vertebrates, inhabits shallow temperate waters in the worldwide ocean. A unique combination of simple stereotyped embryogenesis, regulative post-embryonic stages and ecologically relevant diversity makes Ciona a premier model for marine systems life sciences, from cells and molecules to populations and ecosystems.

Endowed with formidable chemical defenses, spectacular coloration and diverse parental care strategies, poison frogs are a powerful comparative model for understanding how ecology, genetics and neurobiology intersect to shape the evolution of physiology and behavior.

Studying the gray mouse lemur (Microcebus murinus), one of the world’s smallest primates, in its natural habitat and in the laboratory provides unique perspectives on primate brain evolution, cognition, aging and neurodegenerative diseases, on an accelerated timescale and at a substantially lower cost as compared with larger primate models.

Cichlid fishes are a family of thousands of recently evolved species. As charismatic laboratory models, they are useful for studying anatomical, physiological and behavioral traits that vary across these closely related species.

The globally distributed marine tubeworm Hydroides elegans is emerging as a powerful model for studying bacteria-induced metamorphosis, and offers insights into developmental biology, marine ecology and host–microbe interactions.

The Australian bearded dragon is so called for its distinctive ‘beard’ of spiky scales that can darken and expand during social and defensive displays. This lizard has become a reptilian model system to study the evolution, function and dynamics of neurons and neural circuits (including during sleep) in the amniote brain.

Miniature, transparent Danionella fishes, which are among the smallest living adult vertebrates, allow investigation of general principles of brain-wide neural circuits and evolutionary and developmental mechanisms for neurobehavioral innovations.

Bats, the only flying mammals, comprise almost 25% of mammalian species. They are excellent navigators, highly social, and extremely long-lived. Their sense of echolocation has been studied for many years — but many species possess also excellent vision and olfaction. In recent years, bats have emerged as new models for neurobiology of navigation, social neuroscience, aging, and immunity.

After having been largely neglected for more than a century, the tiny marine animal Trichoplax adhaerens is enjoying a revival and is now poised to become a mainstream model organism for the study of epithelial evolution, diversification and specialization.

Brown seaweeds are multicellular eukaryotes that have been evolving independently of animals and plants for more than a billion years. The filamentous brown alga Ectocarpus has been used as a model to understand the biology of these enigmatic organisms and to shed light on a range of major questions, from the molecular basis of complex developmental patterns to the evolution of sex.

The green alga Chlamydomonas reinhardtii is a useful reference organism for studying photosynthesis, cilia and the cell cycle. Like many other algae, it exhibits daily rhythms in gene expression and behavior that are in sync with the rising and setting of the sun.

Originally from central Mexico and now found worldwide, the axolotl is a prominent model organism in numerous fields of research.

Astyanax mexicanus exists in two forms: a surface form that is abundantly distributed throughout freshwater bodies in Middle America and a blind subterranean form endemic to caves in northeastern Mexico. These diverse fish populations have become a vertebrate model for investigating the genetic basis of environmental adaptation.

Planaria are a group of worms within the phylum Platyhelminthes (flatworms). Many species, including Schmidtea mediterranea, have the ability to regenerate their body from small pieces of tissue and are easy to keep in the laboratory, which makes them a prime model system for studying whole-body regeneration.

Harvester ants live in desert grasslands and eat seeds. Colonies manage water stress by regulating foraging using olfactory interactions between outgoing and returning foragers. A long-term study in New Mexico shows how this collective behavior is evolving in drought conditions.

A naturally short-lived fish opens the gates for rapid exploration of vertebrate aging.

Parhyale hawaiensis comes from tropical intertidal shores and mangroves. In research, it is used to explore topics ranging from embryonic development and regeneration, to tidal rhythms and environmental pollution.

Tardigrades are everywhere. They’re tiny — usually under a millimeter long — and they’re mostly transparent, so they’re easy to miss. But you probably walk by them every day. We’ve been grooming them as emerging models for studying how body forms evolve and how biological materials can survive extreme conditions.

In this issue, we are delighted to launch a new regular feature: the Creature Column.

Beyond the well-known pantheon of model organisms are others. A shift is underway to level the playing field.

The life sciences are dominated by a handful of model organisms, but unusual creatures have their place in biological research as well.