Age of Arthropods

In 2019, the 1000th California condor chick was born. It marked an important milestone for the California Condor Recovery Program and those who participated in the project were overwhelmed by joy (Rosane, O., 2019). After all, the population consisted of only 22 condors in 1982. The California Condor Recovery Program began in 1979, when the U.S. Fish and Wildlife Service realized the condors wouldn't make it without the help of humans. It was decided to capture all wild California condors and integrate them into an already existing breeding program. Because the population was so crucially low, conservationists did everything to keep them as healthy as possible. In order to get rid of any parasites, all condors were deloused and treated with pesticide. But there was one thing that no-one took into consideration: the birds were home to a species-specific louse called Coplocephalum californici . As the population of their hosts were declining, their numbers were also going do

In part one, we discussed the phylogenetic placement of Chasmataspididae and concluded that Chasmataspididae is closer to Xiphosura than to Eurypterida. However, Chasmataspidida consists of two clades: Chasmataspididae and Diploaspididae. Surprisingly enough, the case of Diploaspididae is entirely different than that of Chasmataspididae. Even though they are relatively unknown by the public, their fossil record is quite extensive. Unlike Chasmataspididae, which only contains one genus, Diploaspididae consists of as much as 10 genera, all well-spread across the globe (ranging from the USA to Russia). Recent discoveries have revealed that Diploaspidids filled in more ecological niches as previously thought. A reconstruction of Hoplitaspis , a suprisingly well-developed predator. It even has forward-placed eyes, providing improved binocular vision. Figure obtained from Lamsdell et al. (2019). When looking at Diploaspidids, the resemblance to Eurypterids quickly becomes obv

Megarachne servinei is quite a strange critter, even for an Eurypterid. It possesses unusual structures, such as an enlarged and round second tergite, a shovel shaped cephalothorax and blades on its appendages. The function of many of these structures remains unknown up until this day, but I have several hypotheses that might possibly explain what purpose they served and how they might have looked like in life. The enlarged and round second tergite is perhaps the most peculiar structure of Mycteroptids. The shape and texture caused Hu ̈nicken 1980 to believe that Megarachne was a giant mygalomorph spider. Selden et al. 2005 wasn’t able to figure out what function it could have, stating that “the function of the large, circular second opisthosomal tergite remains a mystery.” The holotype of Megarachne servinei . The second tergite was mistaken for the opisthosoma of a spider. However, one thing I noticed at looking at the holotype of Woodwardopterus scabrosus , a close re

Chasmataspidida is an order of peculiar arthropods, which seem to resemble both xiphosurans and eurypterids. Their phylogenetic placement is still very uncertain because of this. Therefore, I decided to learn more about these creatures in order to see if I would be able to come up with my own hypothesis regarding their phylogenetic placement. Chasmataspidida consists of two clades: Chasmataspididae (one genus) and Diploaspididae (10 genera). I decided to focus on Chasmataspididae first. The only genus in Chasmataspididae is Chasmataspis . It was first described by Caster and Brooks, and later redescribed by Dunlop et al. Reconstruction of Chasmataspis according to Caster and Brooks. Something that sets Chasmataspidids apart from Eurypterids is the clear separation of the carapace, abdomen and postabdomen, making them resemble Xiphosurans a lot more. Reconstruction of Chasmataspis by Dunlop et al. Dunlop et al. noted that Chasmataspis would have likely h