Papers by Jose Ruben Guzman-Gutierrez
Memoria del Septimo Seminario de Investigacion en la UAA, 2006
En este trabajo se analizaron, mediante espectroscopia Raman, muestras fósiles de trilobites, amo... more En este trabajo se analizaron, mediante espectroscopia Raman, muestras fósiles de trilobites, amonita, y restos de huesos largos de équidos, donde estos últimos fueron recolectados en el lago de Chapala. Los espectros Raman fueron medidos en diferentes zonas de cada muestra a temperatura ambiente al emplear la longitud de onda de excitación de 830 y 785 nm. De los espectros Raman obtenidos se observó que hay variaciones en el proceso de fosilización del interior al exterior de la muestra para los fósiles de amonitas. También, se observaron diferencias para diversas zonas del mismo hueso fósil debido al enraizamiento.
Journal of South American Earth Sciences, 2023
The Mosasauridae underwent a major radiation early in the Late Cretaceous, with the subfamilies P... more The Mosasauridae underwent a major radiation early in the Late Cretaceous, with the subfamilies Plioplatecarpini and Tylosaurini appearing in the Turonian. Here we report an almost complete mosasaur skull assigned to the plioplatecarpine genus Yaguarasaurus. The specimen was discovered southwest of Vallecillo in the northeastern Mexico state of Nuevo Leon, about 80 km north of Monterrey, in a laminated limestone layer of the upper member of the Agua Nueva Formation (Upper Turonian - ?Lower Coniacian). The specimen is referred to as a new species, Y. regiomontanus. This is the first report of Yaguarasaurus from Mexico and the most complete of the Americas. At roughly 5 m in length, it is one of the earliest large mosasaurids. Along with Yaguarasaurus columbianus, Russellosaurus coheni, and an unnamed plioplatecarpine from Texas, it documents the rapid diversification and expansion of plioplatecarpines in the marine realm in the Turonian.
We report the recovery of the holotype material for the land tortoise Gopherus auffenbergi, repor... more We report the recovery of the holotype material for the land tortoise Gopherus auffenbergi, reported by Oswaldo Mooser in 1971 from the Pleistocene Cedazo local fauna in Aguascalientes, which had been long lost since the death of Mooser in 1983. The recovered material consist in the complete carapace and some postcranial elements.
We report a new Pleistocene vertebrate fossil locality outcropping near the town of Emilio Carran... more We report a new Pleistocene vertebrate fossil locality outcropping near the town of Emilio Carranza, southwest of Zacatecas State, Mexico. The fossil material recovered so far include molars and tusks of the proboscidean Mammuthus, molariforms of the equid genus Equus as well as postcranial material assigned to both genera.
Preliminary taxonomic results on a new local faunal assemblage from the Late Miocene assigned to ... more Preliminary taxonomic results on a new local faunal assemblage from the Late Miocene assigned to the Hemphillian NALMA that have been collected in the continental facies outcropping near the townships of Tecolotlan and Juchitlan, in the Mexican State of Jalisco.
En 1885, el geólogo Mariano Bárcena escribió un comentario acerca de unas "impresiones fisio... more En 1885, el geólogo Mariano Bárcena escribió un comentario acerca de unas "impresiones fisiológicas" en las cercanías de San Juan de los Lagos, Jalisco. En 1894, el naturalista francés Alfredo Dugés, publicó el reporte formal de dichas impresiones donde registra huellas fósiles de aves y de un felino del Plio-Pleistoceno. Ciento doce años después, el análisis de la paleoicnofauna reportada por Dugés, permitió el redescubrimiento del material ilustrado por él, así como la presencia de material adicional en otras colecciones, similar al descrito por Dugés. El sitio de donde proceden las huellas, se localizó en el municipio de San Juan de los Lagos; las huellas se encuentran conservadas en sedimentos lacustres con influencia volcánica. La diversidad de huellas de vertebrados no sólo se restringe a las identificadas inicialmente; se conoce ahora la existencia de huellas de aves del orden Charadriformes (dos morfotipos relativos a la morfofamilia Avipedidae), huellas de artiodá...
Oswaldo Mooser (1903-1983) describe lo que considera una asociación faunística unitaria del Pleis... more Oswaldo Mooser (1903-1983) describe lo que considera una asociación faunística unitaria del Pleistoceno medio procedente de la región central de Aguascalientes, denom-inándola "Fauna Cedazo". El estudio posterior de algunos de los materiales colectados por Mooser nos ha permitido cuestionar la contemporaneidad de los taxa reportados, lo cual sugiere que se trata de representantes de diferentes edades que de alguna manera se han mezclado en los depósitos fluviales (arroyos de El Cedazo y San Francisco, principalmente), por ejemplo, la presencia tanto del complejo Mammuthus hayi/meridionalis como de Mam-muthus columbi en la Fauna Cedazo. Aunque posteriormente otros investigadores han reportado hallazgos de mega-fauna pleistocénica en el área, hasta ahora no ha sido posible dilucidar satisfactoriamente esta cuestión. Aunado a esta problemática, debido al crecimiento de la zona urbana de la ciudad de Aguascalientes, la mayoría de las localidades originalmente trabajadas por Mo...
Journal of South American Earth Sciences, 2017
During the past decade, three new endemic taxa of ceratopsian ornithischians have been described ... more During the past decade, three new endemic taxa of ceratopsian ornithischians have been described from Mexico. Apparently, this group experienced a regional diversification in this area. To date Mexican Ceratopsia are represented by three species, one of which is a centrosaurine and two are chasmosaurines. Here we provide a critical review on Mexican ceratopsians and formally name a new centrosaurine ceratopsid species from the Aguja Formation as Yehuecauhceratops mudei. We also discuss possible causes for the rapid endemic diversification of Mexican ceratopsians.
We present a proof of a conjecture about the relationship between Baxter permutations and pairs o... more We present a proof of a conjecture about the relationship between Baxter permutations and pairs of alternating sign matrices that are produced from domino tilings of Aztec diamonds. It is shown that if and only if a tiling corresponds to a pair of ASMs that are both permutation matrices, the larger permutation matrix corresponds to a Baxter permutation. There has been a thriving literature on both pattern-avoiding permutations of various kinds [1] [2] and tilings of regions using dominos or rhombuses as tiles [3] [4]. However, there have not as of yet been many links between these two areas of enumerative combinatorics. This paper gives one such link.
New hadrosaurid postcranial material is reported, collected near Presa San Antonio, Parras de la ... more New hadrosaurid postcranial material is reported, collected near Presa San Antonio, Parras de la Fuente municipality, Coahuila, Mexico, in a sedimentary sequence belonging to the upper Campanian of the Cerro del Pueblo Formation, in the Parras Basin. The skeletal remains include partial elements from the pelvic girdle (left ilium, right pubis, ischium, and incomplete sacrum), a distal end of a left femur, almost complete right and left tibiae, right metatarsals II and IV, cervical and caudal vertebrae. Also, partially complete forelimb elements are present, which are still under preparation. The pubis shows characters of the Lambeosaurinae morphotypes, but the lack of cranial elements does not allow us to directly differentiate this specimen from the already described hadrosaurid taxa from the studied area, such as Velafrons coahuilensis, Latirhinus uitstlani, and Kritosaurus navajovius. This specimen, referred as Lambeosaurinae indet., adds to the fossil record of the hadrosaurids ...
Here we report new hadrosaur remains recovered from the Cerro del Pueblo Formation (Upper Cretace... more Here we report new hadrosaur remains recovered from the Cerro del Pueblo Formation (Upper Cretaceous: Campanian) at La Parrita locality, northeastern Mexico. Although the material is fragmentary, the identification of dental microwear in three out of the four teeth collected is notable. This sample allows for a preliminary assessment of hadrosaur dental microwear from this geographic region and time frame. The variables studied were the orientation and average count of scratches, average count of pits, and average microwear feature width in an area of 400 X 400 μm at 35X magnification. The results show a predominance of dorsodistally-ventromesially inclined scratches in all three teeth indicating that the mandible primarily moved in an orthopalinal direction during the power stroke. The pattern of scratch orientation we recorded is comparable to that reported for different hadrosaur species from Alberta, Canada, and Wyoming, U.S.A.; suggesting similar jaw mechanics in the hadrosaurs...
3y una mandibula asociada con ambos I 2 y las series P 3 -M 3 , parte anterior de una mandibula a... more 3y una mandibula asociada con ambos I 2 y las series P 3 -M 3 , parte anterior de una mandibula aislada con el I 2 izquierdo y ambas series P 3 -M 3 , una mandibula aislada con la serie P 3 -M 3 pero sin sinfisis, molares superiores aislados, dos magno derechos, un metacarpo III izquierdo y la primera falange del digito III derecho. Se observaron variaciones morfologicas en el material examinado que refleja diferencias de edad y/o sexo entre los individuos. Teleoceras hicksi se encuentra en la Cuenca de Tecolotan asociado con Dinohippus mexicanus, Nannippus aztecus, Neohipparion eurystyle, Astrohippus stockii y Borophagus secundus, por lo que la edad de la fauna corresponde al Henfiliano tardio. Palabras clave: Cuenca de Tecolotlan, Jalisco, Rhinocerotidae, Teleoceras hicksi, Henfiliano tardio.
Swiss Journal of Palaeontology, 2018
Isolated bones and osteoderms of ankylosaurian dinosaurs recovered from Late Cretaceous sediments... more Isolated bones and osteoderms of ankylosaurian dinosaurs recovered from Late Cretaceous sediments of northern Coahuila, northeastern Mexico, have been identified as remains of nodosaurids. Here, we summarize these discoveries and provide a review on Mexican Ankylosauria from a taxonomic perspective. We also present a new taxon, Acantholipan gonzalezi gen. et sp. nov. from the Pen Formation and provide a phylogenetic analysis integrating the new taxon. A. gonzalezi is the first named ankylosaur from Mexico that adds to the currently rare nodosaurid diversity from southern Laramidia.
Sobre descubrimientos paleontologicos realizados hacia finales del siglo XIX de diversos grupos d... more Sobre descubrimientos paleontologicos realizados hacia finales del siglo XIX de diversos grupos de vertebrados fosiles, principalmente megafauna pleistocenica, con antiguedades que oscilan entre 300,000 y 11,800 anos, en el estado de Puebla que despertaron el interes de importantes paleontologos, geologos y arqueologos como Edward D. Cope, Manuel Villada, Johannes Felix, Hans Lenk, Henry F. Osborn, Wilhelm Freudenberg y Juan Armenta Camacho, entre muchos mas.
Hantkeniana
The two study areas are located in the northeast part of the Chihuahua state, Mexico; the first o... more The two study areas are located in the northeast part of the Chihuahua state, Mexico; the first one is called "Región Altares" and the second one is known as "Región San Miguel". The deposits present in the Región Altares are exclusively from the continental and marine members of the Late Cretaceous Aguja Formation; the Región San Miguel has some small windows that show badly weathered portions of the Javelina Formation, and also displays outcrops of the continental and marine sections of the Aguja Formation. The age range extends from Late Campa-nian to Late Maastrichtian (83.5-65.5 Ma). The continental member of the Aguja Formation consists of greenish-gray mudstones and yellowish-gray sandstones that present ripple marks in the lower part of the section along with cross stratifi-cation, as well as limonite lenses in smaller propor-tion. The marine member is conformed by a sequence of dark gray mudstones, and yellowish-gray limolites.
Dr. Alfredo Dugés was an eminent French naturalist who lived in Guanajuato, Mexico, in the late X... more Dr. Alfredo Dugés was an eminent French naturalist who lived in Guanajuato, Mexico, in the late XIX and early XX centuries. He is well-known for his studies in Herpetology, Ictiology and Ornitology of Mexico, but he also made very important contributions to the Mexican Vertebrate Paleontology. Fortunately we have been able to find most of his paleontological collections are still housed in Guanajuato, Mexico; in the School of Mines and in the Museum that bears his name.
Uploads
Papers by Jose Ruben Guzman-Gutierrez
It was publishec by the Centro de Vinculación para el Desarrollo Sustentable (CEVDSU A.C.) with the support of the program Coinversión Social 2010 of the Instituto Nacional de Desarrollo Social, Mexico.
Los primeros reportes de huellas de dinosaurio corresponden a operarios de la empresa a cargo de la apertura del camino que actualmente pasa por la parte media occidental del Sinclinal de Chaupi Cocha, cuya dimensión es de aproximadamente 10 kilómetros.