* Astronomy

Human-sized lobster-like animal roamed ancient seas

A two metre long lobster-like animal that lived 480 million years ago used spine-covered 'limbs' on its head to catch food, fossils have revealed.
The new species, named Aegirocassis benmoulae after the Moroccan fossil hunter Mohamed Ben Moula who discovered the remains, also had paired swimming flaps along its body
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When Trilobites Ruled the World

In a series of recent reports, scientists describe fresh insights into the trilobite's crystal-eyed visual system, unique in the animal kingdom, and its distinctive body plan, a hashtag of horizontal segments arrayed along three vertical lobes that allowed the trilobite to roll up into a defensive ball against predators and sea squalls.
Other researchers have found evidence that some trilobites were highly social, migrating long distances in a head-to-tail procession as they searched for food, or gathering together during molting season at a kind of Trilo's Retreat, where the trilobites could simultaneously shuck off their carapaces and seek out mates.
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Title: Demecology in the Cambrian -- synchronised molting in arthropods from the Burgess Shale
Authors: Joachim T Haug, Jean-Bernard Caron and Carolin Haug

Background
The Burgess Shale is well known for its preservation of a diverse soft-bodied biota dating from the Cambrian period (Series 3, Stage 5). While previous paleoecological studies have focused on particular species (autecology) or entire paleocommunities (synecology), studies on the ecology of populations (= demecology) of Burgess Shale organisms have remained mainly anecdotal.

Results
Here, we present evidence for mass molting events in two unrelated arthropods from the Burgess Shale Walcott Quarry, Canadaspis perfecta and a megacheiran referred to as Alalcomenaeus sp.

Conclusions
These findings suggest that the triggers for such supposed synchronised molting appeared early on during the Cambrian radiation, and synchronised molting in the Cambrian may have had similar functions in the past as it does today. In addition, the finding of numerous juvenile Alalcomenaeus sp. molts associated with the putative alga Dictyophycus suggests a possible nursery habitat. In this nursery habitat a population of this animal might have found a more protected environment in which to spend critical developmental phases, as do many modern species today.

Source

Cambrian Fossil Pushes Back Evolution of Complex Brains

The remarkably well-preserved fossil of an extinct arthropod shows that anatomically complex brains evolved earlier than previously thought and have changed little over the course of evolution. According to University of Arizona neurobiologist Nicholas Strausfeld, who co-authored the study describing the specimen, the fossil is the earliest known to show a brain.
The discovery will be published in the Oct. 11 issue of the journal Nature.
Embedded in mudstones deposited during the Cambrian period 520 million years ago in what today is the Yunnan Province in China, the approximately 3-inch-long fossil, which belongs to the species Fuxianhuia protensa, represents an extinct lineage of arthropods combining an advanced brain anatomy with a primitive body plan.
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