Each segment has the same sets of organs and, in most polychaetes, has a pair of parapodia that many species use for locomotion. Septa separate the segments of many species, but are poorly defined or absent in others, and Echiura and Sipuncula show no obvious signs of segmentation.ach segment has the same sets of organs and, in most polychaetes, has a pair of parapodia that many species use for locomotion. Septa separate the segments of many species, but are poorly defined or absent in others, and Echiura and Sipuncula show no obvious signs of segmentation.
Chicxulub is most famous for being near the geographic center of the Chicxulub crater, an impact crater discovered by geologists on the YucatÃ¡n Peninsula and extending into the ocean. It was created by the impact some 65 million years ago of the Chicxulub impactor, an asteroid or comet which caused the CretaceousâPaleogene extinction event, which led to the demise of the dinosaurs.
The coastal village (or puerto) of Chicxulub, 6 km east of the nearest town, Progreso, lies almost exactly on the geographic center of the crater. The name Chicxulub is Yucatec Maya language, where châik means flea or tick, and xulubâ means devil, demon, or horns. In The Chronicle of Chac Xulub Chen, Nakuk Pech says that the original name of the town (Chac Xulub Chen) means the well of the great horns, and that Chic Xulub may have been a play on words, as it is an idiom for cuckolding.