SUMMARY / RELATED TOPICS

Colonia Vista Alegre

Colonia Vista Alegre is a colonia in the Cuauhtémoc borough of Mexico City just south of the city's historic center. The boundaries of the colonia are formed by the following streets: Calzada de Chabacano to the south, José T. Cuellar to the north, Colonia Paulino Narvarro to the east and Calzada de Tlalpan to the west; the name, which translates to “Happy View,” derives from the view of what was countryside which permitted views of the Popocatépetl and Iztaccíhuatl volcanos as well as the Sierra del Ajusco and Sierra de las Cruces mountains. In 1884, the city council authorized Eduardo Zozaya and Santiago Kerm to establish a number of residential subdivisions on former horse lands known as San Nicolás Tultengo and Santa Crucita. However, the initial project was not successful. Houses did not begin to be constructed in this area until the 1910s. In the 1920s, the area began to develop in an orderly manner. At first the area developed as the large Colonia de la Paz, which included modern Colonia Tránsito, Colonia Esperanza, Colonia Paulino Navarro, Colonia Asturias and Colonia Ampliación Asturias.

In 2003, a four-story buildings on Jose T. Cuellar collapsed while a party was in progress; the event destroyed the home of 13 families and temporarily dislocated 120 families from adjacent buildings. The collapsed building was damaged by the 1985 earthquake, this collapse is attributed to this damage. Subsequent evaluations by the city identified 64 damaged buildings in and near the historic center; these properties were expropriated by the city government in order to prevent another collapse of an occupied building. The area is served by the Mexico City Metro. Metro stations Chabacano

Hypselosaurus

Hypselosaurus was a dubious titanosaurian sauropod that lived in southern France during the Late Cretaceous 70 million years ago in the early Maastrichtian. Hypselosaurus was first described in 1846, but was not formally named until 1869, when Phillip Matheron named it under the binomial Hypselosaurus priscus; the holotype specimen includes a partial hindlimb and a pair of caudal vertebrae, two eggshell fragments were found alongside these bones. Because of the proximity of these eggshells to the fossil remains, many authors, including Matheron and Paul Gervais, have assigned several eggs from the same region of France all to Hypselosaurus, although the variation and differences between these eggs suggest that they do not all belong to the same taxon. Hypselosaurus has been found in the same formation as the dromaeosaurids Variraptor and Pyroraptor, the ornithopod Rhabdodon, the ankylosaurian Rhodanosaurus, as well as indeterminate bones from other groups. In 1846, Pierre Philippe Émile Matheron, a French geologist and paleontologist, described several large bones from Provence, France.

In the spring of 1869, Matheron formally described these remains, including a partial femur and possible tibia and a pair of associated caudal vertebrae, as the holotype specimen of a new taxon, Hypselosaurus priscus. Among the bones, portions of the femur shaft are not preserved, along with a majority of the tibia, while both the fibula and vertebrae are preserved; the layer the fossils came from is from the late Late Cretaceous 70 million years ago. Since its original description, several specimens have been referred to Hypselosaurus. One of these described in 1957 by Albert de Lapparent, includes a caudal vertebra, as well as another vertebra described in 1960 by Bataller. In 1993, a review of European sauropods stated that Hypselosaurus was a nomen dubium, that its holotype could not be verifiably distinguished from other sauropods in the same, many other, regions. Based on this, the material, referred to Hypselosaurus by several other authors would have to be considered an intermediate titanosaur.

In addition to the holotype skeleton, Matheron described two fragments of a spherical or ellipsoid fossil in 1869. These fragments were studied for some time by Matheron and his contemporary French paleontologists, the only probable conclusion was that they were fragments of eggshells; the eggs were proposed to have been larger than those of Aepyornis when complete, Matheron suggested that they either were a large bird egg, or belonged to Hypselosaurus. When named, Matheron proposed that Hypselosaurus was an aquatic crocodile, as was suggested for similar taxa like Pelorosaurus, Cetiosaurus and Steneosaurus by their describers. Matheron noted that the long bones the femur, lacked medullary bone, thus proposed that it could not have been terrestrial like Iguanodon. Hypselosaurus was a proposed to be 15 m in length, when it was considered a crocodilian, which would have made it one of the largest of the group. However, a modern estimate as a titanosaur has put Hypselosaurus at around 12.0 m, with a rough weight estimate of 7.3–14.5 t.

One of the smaller titanosaurs, measures only 7.5 m long. The left femur of Hypselosaurus, at 80 cm in length, is quite eroded, with both the femoral head and the distal condyles being eroded and distorted by sediment; the femur is sinuous, narrows antero-posteriorly, becoming a subquadrangular oval 17 cm wide and only 7 cm long. The internal shaft is spongey, although the internal bone is only loosely attached, the femur lacks a medullary canal; as preserved, the left tibia is incomplete, with only a small section of the shaft, just proximal to the distal condyles, known. Like the femur, there is no medullary canal present, the spongey internal bone is asymmetrically dense. Few other features can be identified, among cross-section of the bone; the tibia is ovoid in cross-section, with the anterior diameter 11 cm long, 5.5 cm wide. The fibula, at 55 cm in length, corresponds well with the size of the tibia; the fibula is an equilateral triangle in cross-section, with the inner face concave and outer face convex.

The flatter surface of the fibula is 18 cm wide, opposite ridge protrudes 7 cm from this. Two caudal vertebrae were preserved, although there would have been a much larger number in the tail. Both bones are nearly identical in every feature, but the anterior has is larger dimensions; the vertebrae are not compressed laterally, instead being compressed vertically to a width of 11 cm and a height of 7 cm in the posterior vertebra. Both vertebrae are procoelous, with the anterior articular face being concave, the posterior face being convex; the larger vertebra is 12 cm at its widest, but it narrows towards the middle of its length until it is only 8 cm wide. Both vertebrae preserved the zygapophyses, articular processes that connect the consecutive vertebrae; the vertebrae are overall similar to those of Pelorosaurus Eggs attributed to Hypselosaurus by Matheron and Paul Gervais have been found in France since 1846, were the earliest dinosaur eggs discovered, although they were not recognized as being dinosaurian for several decades.

The eggs are unusually large. Age determination studies performed on the fossilized remains have been inconclusive, with results ran