Stuart S. Sumida

Bio: Stuart S. Sumida is an academic researcher from California State University, San Bernardino. The author has contributed to research in topics: Permian & Synapsid. The author has an hindex of 17, co-authored 35 publications receiving 978 citations. Previous affiliations of Stuart S. Sumida include Carnegie Museum of Natural History & California State University.

A stem batrachian from the Early Permian of Texas and the origin of frogs and salamanders

Abstract: The origin of the amphibians (frogs, salamanders and caecilians) is one of the most controversial questions in vertebrate evolution, because of the large morphological and temporal gaps between today's amphibians and the extinct fossil forms The discovery of an unusually complete Palaeozoic amphibian from the Early Permian of Texas has now helped to fill that gap The new fossil has the overall appearance of a temnospondyl — an archaic amphibian — but boasts many characteristic features seen in modern frogs, toads and salamanders A phylogenetic analysis splits the modern amphibia into two groups, separating at some time before 330 million years ago, with frogs, toads and salamanders related to temnospondyls, and caecilians more closely related to the lepospondyls, another group of archaic amphibians Anderson and colleagues describe a fossil amphibian from the Early Permian of Texas that has the chassis of a temnospondyl but with the addition of many features seen in modern frogs, toads and salamanders A phylogenetic analysis splits modern Amphibia into two groups, with frogs, toads and salamanders related to temnospondyls, and caecilians to leopspndyls The origin of extant amphibians (Lissamphibia: frogs, salamanders and caecilians) is one of the most controversial questions in vertebrate evolution, owing to large morphological and temporal gaps in the fossil record1,2,3 Current discussions focus on three competing hypotheses: a monophyletic origin within either Temnospondyli4,5,6,7 or Lepospondyli8,9,10, or a polyphyletic origin with frogs and salamanders arising among temnospondyls and caecilians among the lepospondyls11,12,13,14,15,16 Recent molecular analyses are also controversial, with estimations for the batrachian (frog–salamander) divergence significantly older than the palaeontological evidence supports17,18 Here we report the discovery of an amphibamid temnospondyl from the Early Permian of Texas that bridges the gap between other Palaeozoic amphibians and the earliest known salientians19,20 and caudatans21 from the Mesozoic The presence of a mosaic of salientian and caudatan characters in this small fossil makes it a key taxon close to the batrachian (frog and salamander) divergence Phylogenetic analysis suggests that the batrachian divergence occurred in the Middle Permian, rather than the late Carboniferous as recently estimated using molecular clocks18,22, but the divergence with caecilians corresponds to the deep split between temnospondyls and lepospondyls, which is congruent with the molecular estimates

Early Permian Bipedal Reptile

Abstract: A 290-million-year-old reptilian skeleton from the Lower Permian (Asselian) of Germany provides evidence of abilities for cursorial bipedal locomotion, employing a parasagittal digitigrade posture. The skeleton is of a small bolosaurid, Eudibamus cursoris, gen. et sp. nov., and confirms the widespread distribution of Bolosauridae across Laurasia during this early stage of amniote evolution. E. cursoris is the oldest known representative of Parareptilia, a major clade of reptiles.

Lower Permian Terrestrial Paleoenvironments and Vertebrate Paleoecology of the Tambach Basin (Thuringia, Central Germany): The Upland Holy Grail

Abstract: The Bromacker section of the Lower Permian, Tambach Formation, in central Germany, yields an important fossil-vertebrate assemblage that was deposited in an upland setting near the center of a small, internally-drained paleo-graben. The fossil-vertebrate assemblage shares many taxa in common with others that are well-documented from North America, but is atypical in the: (1) unusually large abundance of the terrestrial herbivore Diadectes; (2) complete absence of aquatic and semi-aquatic vertebrates; and (3) rarity of medium-to-large carnivorous synapsids. The graben setting and the low-diversity, terrestrial, fossil-vertebrate assemblage together comprise a unique upland paleoecosystem, heretofore undocumented in the Early Permian. The composition of and relative abundances within the assemblage at Bromacker suggest that experiments with “high-fiber” vertebrate herbivores as the dominant or significant basal component of vertebrate food webs had begun by the Early Permian, but only in settings w...

A new diadectid (diadectomorpha), orobates pabsti, from the early permian of central germany

Abstract: A new genus and species of the herbivorous Diadectidae, Orobates pabsti, is described on the basis of several specimens, including two complete, articulated skeletons, a skull with partial postcranium, a partial skull, and a dentigerous jaw fragment. All were collected from the Lower Permian (Wolfcampian) Tambach Formation, lowermost formational unit of the Upper Rotliegend of the Bromacker quarry locality in the midregion of the Thuringian Forest near Gotha, central Germany. A combination of autapomorphic and plesiomorphic character states clearly distinguishes O. pabsti from all other well-known members of Diadectidae and identifies it as the sister taxon to all other diadectids. The description of Orobates pabsti expands further our understanding of the Late Pennsylvanian-Early Permian Diadectidae and records the earliest specialization of tetrapods to high-fiber herbivory. On the basis of paleobiological and paleoenvironmental data only one other Early Permian locality is comparable to the Br...

Redescription of Seymouria sanjuanensis (Seymouriamorpha) from the Lower Permian of Germany based on complete, mature specimens with a discussion of paleoecology of the Bromacker locality assemblage

Abstract: Two nearly complete, articulated, mature specimens of the amphibian Seymouria are described from the Lower Permian Tambach Formation, lowermost unit of the Upper Rotliegend, of the Bromacker locality in the mid-region of the Thuringian Forest near Gotha, central Germany. They are assigned to S. sanjuanensis, known elsewhere only from the Lower Permian deposits of Wolfcampian age in the southwestern United States. This confirms an earlier referral of two immature specimens from the same locality to this species. The new specimens are unusual in being highly ossified and allow for the first time a complete description of the carpus and tarsus of Seymouria. The Bromacker Seymouria specimens are part of an assemblage that is unique among Lower Permian localities in Europe in its taxonomic composition and its depositional environment. The Bromacker vertebrate assemblage includes many taxa found elsewhere only in the Lower Permian of the United States. All are adapted to a highly terrestrial existence,...

The amphibian tree of life

Abstract: The evidentiary basis of the currently accepted classification of living amphibians is discussed and shown not to warrant the degree of authority conferred on it by use and tradition. A new taxonomy of living amphibians is proposed to correct the deficiencies of the old one. This new taxonomy is based on the largest phylogenetic analysis of living Amphibia so far accomplished. We combined the comparative anatomical character evidence of Haas (2003) with DNA sequences from the mitochondrial transcription unit H1 (12S and 16S ribosomal RNA and tRNAValine genes, ≈ 2,400 bp of mitochondrial sequences) and the nuclear genes histone H3, rhodopsin, tyrosinase, and seven in absentia, and the large ribosomal subunit 28S (≈ 2,300 bp of nuclear sequences; ca. 1.8 million base pairs; x = 3.7 kb/terminal). The dataset includes 532 terminals sampled from 522 species representative of the global diversity of amphibians as well as seven of the closest living relatives of amphibians for outgroup comparisons. The...

The Osteology of the Reptiles

Abstract: IN no domain of zoological science have the con tributions of American naturalists been more splendid than in that of vertebrate palaeontology, and in the list of pioneer workers in this domain an honoured place will always be accorded to Samuel Wendell Williston, who, born and nurtured in obscurity, had by the time of his death in 1918 won his way to recogni tion as the chief authority upon the extinct amphibians and reptiles. Apart from his specialist papers upon fossil vertebrates and upon modern dipterous flies, Williston was well known to the general zoologist for his excellent book on “Water Reptiles of the Past and Present,” published in 1914, and during the last year of his life he was busily engaged in the preparation of a second work of a general character on “The Reptiles of the World, Recent and Fossil.” The volume now under review comprises the main part of this general work, so far as it had been completed at the time of the author's death, put into shape and edited at the competent hands of Prof. W. K. Gregory. The Osteology of the Reptiles. By Prof. Samuel Wendell Williston. Arranged and edited by Prof. William King Gregory. Pp. xiii + 300. (Cambridge, Mass.: Harvard University Press; London: Oxford University Press, 1925.) 18s. 6d. net.

Ichnology: Organism-Substrate Interactions in Space and Time

Abstract: Ichnology is the study of traces created in the substrate by living organisms. This is the first book to systematically cover basic concepts and applications in both paleobiology and sedimentology, bridging the gap between the two main facets of the field. It emphasizes the importance of understanding ecologic controls on benthic fauna distribution and the role of burrowing organisms in changing their environments. A detailed analysis of the ichnology of a range of depositional environments is presented using examples from the Precambrian to the recent, and the use of trace fossils in facies analysis and sequence stratigraphy is discussed. The potential for biogenic structures to provide valuable information and solve problems in a wide range of fields is also highlighted. An invaluable resource for researchers and graduate students in paleontology, sedimentology and sequence stratigraphy, this book will also be of interest to industry professionals working in petroleum geoscience.