Early dinosaurs found in Argentina.Early dinosaurs found in Argentina Just what makes a dinosaur a dinosaur? Fifteen years ago, paleontologists thought they had a clear answer, but fossil finds since then have muddied the issue. One of the problems, says researcher Paul C. Sereno from the University of Chicago, is that scientists working in northwestern Argentina uncovered primitive dinosaur ancestors Ancestors See also father; heredity; mother; origins; parents; race. archaism an inclination toward old-fashioned things, speech, or actions, especially those of one’s ancestors. Also archaicism. — archaist, n. that had developed features thought to be unique to dinosaurs. Hoping to fill in the details about some of the earliest dinosaurs, Sereno traveled to Argentina earlier this year and excavated in the Ischigualasto formation near San Juan San Juan, city, Argentina San Juan (săn wän, Span. sän hwän), city (1991 pop. 353,476), capital of San Juan prov., W Argentina. It is a commercial and industrial center in an agricultural region. along with colleagues from Argentina and the University of Chicago. Among other finds, the group discovered several important pieces of the primitive dinosaur Herrerasaurus. Previously, scientists had only some vertebrae Vertebrae Bones in the cervical, thoracic, and lumbar regions of the body that make up the vertebral column. Vertebrae have a central foramen (hole), and their superposition makes up the vertebral canal that encloses the spinal cord. , a pelvis pelvis, bony, basin-shaped structure that supports the organs of the lower abdomen. It receives the weight of the upper body and distributes it to the legs; it also forms the base for numerous muscle attachments. and a hind hind 1. emanating from or pertaining to hindlimb. 2. adult female deer, especially red and other large species. blue hind a hind which has not borne young. limb from the animal. But this year's finds have filled in all the missing parts, Sereno says. "Within this information that we have found this year we will be able to know much more about the skeleton of these primitive dinosaurs. We will therefore be able to define what a dinosaur is more precisely." |
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