A cicada of the genus Magicicada, which are known for their long life-cycles and 17-year emergence pattern. This year will mark the 17th year in the life-cycle of a large generation (Brood II), meaning the north eastern coast of the US will see swarms of these beauties and be overcome by the cacophony of their mating calls through the late spring and summer. Next summer, the midwest will see the emergence of Brood III. This phenomenon has been affectionately referred to as cicadapocalypse.

Despite being large and ominous-looking, cicadas are entirely harmless. They neither bite nor sting and they aren’t excessively destructive to vegetation or infrastructure.

Photo © Richard Leung

The family tree of fishes, showing the evolution of major groups through geological time. Numerous lineages of extinct fishes are not shown. Widened areas in the lines of descent indicate periods of adaptive radiation and the relative number of species in each group. The lobe-finned fishes (sarcopterygians), for example, flourished in the Devonian period, but declined and are today represented by only four surviving genera (lungfishes and coelacanths). Sharks and rays, which radiated during the Carboniferous period, came dangerously close to extinction during the Permian period, but staged a recovery in the Mesozoic era and are a secure group today.

Photo © Hickman et al. (2003)

The bones of Ichthyostega (imagined by an artist in this picture), the most thoroughly studied of all early tetrapods, were first discovered on an east Greenland mountainside in 1897 by Swedish scientists looking for three explorers lost two years earlier during an ill-fated attempt to reach the North Pole by hot-air balloon. Later expeditions by Gunnar Säve-Söderberg uncovered skulls of Ichthyostega but Säve-Söderberg died, at age 38, before he was able to make a thorough study of the skulls. His assistant, Erik Jarvik, picked up where he left off and most of what we know about Ichthyostega (and consequently most early tetrapods) today comes from their combined efforts.

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Pictured is an artist’s rendition of an acanthodian, a type of early jawed fish from the Devonian period (400 million years ago). Acanthodians are the earliest known true jawed fishes. They carried less armor than placoderms and are suspected to be the ancestors from which the great diversity of bony-fishes that currently exists evolved from.

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Epaulette soldierfish (Myripristis kuntee) males with parasitic isopods stuck to their heads actually have an increased chance of mating with a female. For some strange reason, female soldierfish are more likely to choose to mate with a male if he is carrying an isopod on his head.

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This feather star, Comantheria briareus, is found on coral reefs in the Pacific. Their long arms stretch up into the water to catch food particles both during the day and at night. Their arms are sticky, like velcro, and will attach to just about anything that brushes up against them. Unfortunately for this crinoid, that means its arms are often accidentally ripped off as they are quite delicate and easily detached.

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The California giant sea cucumber (Parastichopus californicus) is commonly found along the Pacific Coast of North America. It grows up to 50 cm in length and the tube feet along its dorsal side are reduced to papillae and warts.
It has recently been discovered that this species of sea cucumber feeds using its anus. Thanks to this new knowledge, it has been proposed that numerous species of sea cucumber feed using their butts. Scientists have coined the term “bipolar feeding” to describe this behavior.

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Symmetry is common in almost all species within the animal kingdom.
Spherical symmetry means that any plane passing through the center of the organism would divide its body into equal, mirrored halves. This type of symmetry is most common in protozoans and is rarely found in metazoans.
Radial symmetry implies that an object has multiple planes by which it can be divided into equal, mirrored halves, but not an infinite number. Starfish, jellyfish, and sea urchins are all examples of animals with radial symmetry.
Bilateral symmetry is most commonly found in megafauna. It means an organism can be divided on a single plane into two mirrored parts, the left and right halves. Humans are bilaterally symmetrical.

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This makes me so happy.

Excluding chondrosteans, lobe-finned fishes (lungfish and coelacanths), and non-teleost neopterygians (gar and the bowfin), all bony fishes (Osteichthyes) are classified as teleosts. They are the major lineage of neopterygians and shortly after their initial evolution, the diversity within this group of fish exploded, foreshadowing the immense diversity of fish that now exists. Pictured is the anatomy of a yellow perch (Perca flavescens), a common North American freshwater fish.

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