The evolutionary history of sauropod dinosaurs

Most recent studies of dinosaur phylogeny have concentrated on theropods and ornithischians. As a result, the evolutionary relationships of sauropod dinosaurs are poorly understood. In this paper previous studies of sauropod phylogeny are reviewed and contrasted with the results of a recent cladistic analysis. This analysis forms the basis for a reconstruction of sauropod phylogeny. Sauropods diverged from other dinosaurs at some time in the Upper Triassic, but a large part of their early history is totally unknown. Vulcanodon is currently the most primitive sauropod. Many, but perhaps not all, of the Jurassic Chinese sauropods form a monophyletic radiation (the Euhelopodidae) which may reflect the geographic isolation of China during the Lower Jurassic. Members of the Euhelopodidae, such as Mamenchisaurus , are not considered to be closely related to the Diplodocidae. ‘Forked’ chevrons, which have played such an important role in previous studies of sauropod phylogeny, are here considered to have evolved twice within the Sauropoda. This convergence may reflect a correlation between chevron shape and the use of the tail as a weapon within these two sauropod families. The ‘Neosauropoda’ (sister group to the Euhelopodidae) contains the Brachiosauridae, Camarasauridae and the new superfamilies Titanosauroidea and Diplodocoidea. The Cetiosauridae (here defined in a rather restricted sense) is also provisionally included within the Neosauropoda, but may be removed in future studies. The enigmatic Upper Cretaceous sauropod, Opisthocoelicaudia , is thought to be the sister taxon to the Titanosauridae and not a camarasaurid as previously suggested. The Diplodocoidea contains two well established families, the Dicraeosauridae and Diplodocidae, and the new family Nemegtosauridae. Finally, an overview of sauropod phylogeny is compared with recently published palaeogeographic reconstructions. There are many difficulties associated with the analysis of sauropod biogeographic distribution. Nevertheless, some aspects of sauropod phylogeny may be linked to the break-up of Laurasia and Gondwanaland during the Jurassic and Cretaceous.

Download Full-text

Homoplasy and extinction: the phylogeny of cassidulid echinoids (Echinodermata)

Zoological Journal of the Linnean Society ◽

10.1093/zoolinnean/zlz060 ◽

2019 ◽

Vol 187 (3) ◽

pp. 622-660 ◽

Cited By ~ 2

Author(s):

Camilla Souto ◽

Rich Mooi ◽

Luciana Martins ◽

Carla Menegola ◽

Charles R Marshall

Keyword(s):

Evolutionary History ◽

Cladistic Analysis ◽

Future Studies ◽

Novel Traits ◽

The Family ◽

Phylogenetic Resolution ◽

History Of ◽

Recent Species ◽

Taxonomic Implications ◽

High Diversity

Abstract Inclusion of fossils can be crucial to address evolutionary questions, because their unique morphology, often drastically modified in recent species, can improve phylogenetic resolution. We performed a cladistic analysis of 45 cassidulids with 98 characters, which resulted in 24 most parsimonious trees. The strict consensus recovers three major cassiduloid clades, and the monophyly of the family Cassidulidae is not supported. Ancillary analyses to determine the sensitivity of the phylogeny to missing data do not result in significantly different topologies. The taxonomic implications of these results, including the description of a new cassiduloid family and the evolution of some morphological features, are discussed. Cassiduloids (as defined here) most probably originated in the Early Cretaceous, and their evolutionary history has been dominated by high levels of homoplasy and a dearth of unique, novel traits. Despite their high diversity during the Palaeogene, there are only seven extant cassiduloid species, and three of these are relicts of lineages dating back to the Eocene. Future studies of the biology of these poorly known species, some of which brood their young, will yield further insights into the evolutionary history of this group.

Download Full-text

A new family of teiioid lizards from the Upper Cretaceous of Romania with notes on the evolutionary history of early teiioids

Zoological Journal of the Linnean Society ◽

10.1093/zoolinnean/zlx008 ◽

2017 ◽

Author(s):

Vlad A. Codrea ◽

Márton Venczel ◽

Alexandru Solomon

Keyword(s):

Evolutionary History ◽

Upper Cretaceous ◽

New Family ◽

History Of

Download Full-text

Insight into the evolutionary history of freshwater sponges: a new genus and new species of Spongillida (Porifera: Demospongiae) from Upper Cretaceous (Maastrichtian) Deccan intertrappean lacustrine deposits of the Malwa Group, Central India

Cretaceous Research ◽

10.1016/j.cretres.2021.104851 ◽

2021 ◽

pp. 104851

Author(s):

Bandana Samant ◽

Roberto Pronzato ◽

Dhananjay Mahendrakumar Mohabey ◽

Deepesh Kumar ◽

Anup Dhobale ◽

...

Keyword(s):

New Species ◽

Evolutionary History ◽

Upper Cretaceous ◽

New Genus ◽

Central India ◽

Freshwater Sponges ◽

Lacustrine Deposits ◽

History Of ◽

Insight Into

Download Full-text

High resolution integrated microbiostratigraphy of the Lower Jurassic (late Pliensbachian–early Toarcian) of central Italy

Journal of Micropalaeontology ◽

10.1144/jm.17.2.153 ◽

1998 ◽

Vol 17 (2) ◽

pp. 153-172 ◽

Cited By ~ 18

Author(s):

Raffaella Bucefalo Palliani ◽

Emanuela Mattioli

Keyword(s):

High Resolution ◽

Evolutionary History ◽

Central Italy ◽

Lower Jurassic ◽

High Potential ◽

Calcareous Nannofossils ◽

Calcareous Nannofossil ◽

Dinoflagellate Cyst ◽

History Of ◽

Global Events

Abstract. The integrated use of calcareous nannofossil and dinoflagellate cyst events in a study of the late Pliensbachian–early Toarcian interval in central Italy has yielded a high resolution biostratigraphy. The use of both the first and last occurrences of selected taxa belonging to the two phytoplankton groups allows the dating of the sediments with a very refined detail, even when lithologies are unfavourable to the preservation of one fossil group. The evolutionary history of calcareous nannofossils and dinoflagellate cysts during the early Jurassic and its links with global events are responsible for the high potential of this integrated biostratigraphy.

Download Full-text

A new endemic family of New Zealand passerine birds: adding heat to a biodiversity hotspot

Australian Journal of Zoology ◽

10.1071/zo07007 ◽

2007 ◽

Vol 55 (2) ◽

pp. 73 ◽

Cited By ~ 33

Author(s):

Amy Driskell ◽

Les Christidis ◽

B. J. Gill ◽

Walter E. Boles ◽

F. Keith Barker ◽

...

Keyword(s):

New Zealand ◽

Evolutionary History ◽

Divergence Time ◽

Biodiversity Hotspot ◽

Passerine Birds ◽

New Family ◽

Close Relationship ◽

History Of ◽

Anthornis Melanura ◽

Notiomystis Cincta

The results of phylogenetic analysis of two molecular datasets sampling all three endemic New Zealand ‘honeyeaters’ (Prosthemadera novaeseelandiae, Anthornis melanura and Notiomystis cincta) are reported. The undisputed relatedness of the first two species to other honeyeaters (Meliphagidae), and a close relationship between them, are demonstrated. However, our results confirm that Notiomystis is not a honeyeater, but is instead most closely related to the Callaeidae (New Zealand wattlebirds) represented by Philesturnus carunculatus in our study. An estimated divergence time for Notiomystis and Philesturnus of 33.8 mya (Oligocene) suggests a very long evolutionary history of this clade in New Zealand. As a taxonomic interpretation of these data we place Notiomystis in a new family of its own which takes the name Notiomystidae. We expect this new phylogenetic and taxonomic information to assist policy decisions for the conservation of this rare bird.

Download Full-text

The dynamic evolutionary history of genome size in North American woodland salamanders

Genome ◽

10.1139/gen-2016-0166 ◽

2017 ◽

Vol 60 (4) ◽

pp. 285-292 ◽

Cited By ~ 2

Author(s):

Catherine E. Newman ◽

T. Ryan Gregory ◽

Christopher C. Austin

Keyword(s):

Genome Size ◽

Evolutionary History ◽

Future Studies ◽

Plethodontid Salamanders ◽

Genome Size Evolution ◽

Size Evolution ◽

History Of ◽

Large Genome Size ◽

Uncertain Future ◽

Phylogeographic Study

The genus Plethodon is the most species-rich salamander genus in North America, and nearly half of its species face an uncertain future. It is also one of the most diverse families in terms of genome sizes, which range from 1C = 18.2 to 69.3 pg, or 5–20 times larger than the human genome. Large genome size in salamanders results in part from accumulation of transposable elements and is associated with various developmental and physiological traits. However, genome sizes have been reported for only 25% of the species of Plethodon (14 of 55). We collected genome size data for Plethodon serratus to supplement an ongoing phylogeographic study, reconstructed the evolutionary history of genome size in Plethodontidae, and inferred probable genome sizes for the 41 species missing empirical data. Results revealed multiple genome size changes in Plethodon: genomes of western Plethodon increased, whereas genomes of eastern Plethodon decreased, followed by additional decreases or subsequent increases. The estimated genome size of P. serratus was 21 pg. New understanding of variation in genome size evolution, along with genome size inferences for previously unstudied taxa, provide a foundation for future studies on the biology of plethodontid salamanders.

Download Full-text

Wood anatomy of the Mascarene Dombeyoideae: Systematic and ecological implications

IAWA Journal ◽

10.1163/22941932-90000073 ◽

2011 ◽

Vol 32 (4) ◽

pp. 493-519 ◽

Cited By ~ 7

Author(s):

Anaïs Boura ◽

Timothée Le Péchon ◽

Romain Thomas

Keyword(s):

Evolutionary History ◽

Wood Anatomy ◽

Sister Group ◽

Biological Data ◽

Sister Group Relationship ◽

Anatomical Features ◽

Ecological Implications ◽

History Of ◽

Mascarene Islands ◽

Almost All

The Dombeyoideae (Malvaceae) are one of the most diversified groups of plants in the Mascarene Islands. Species of Dombeya Cav., Ruizia Cav. and Trochetia DC. are distributed in almost all parts of the archipelago and show a wide diversity in their growth forms. This study provides the first wood anatomical descriptions of 17 out of the 22 Mascarene species of Dombeyoideae. Their wood anatomy is similar to that of previously described species: wide vessels, presence of both apotracheal and paratracheal parenchyma, and storied structure. In addition, we also found a second wood anatomical pattern with narrower vessels, high vessel frequency and thick-walled fibres. The two aforementioned wood patterns are considered in a phylogenetic context and used to trace the evolutionary history of several wood anatomical features. For example, the pseudoscalariform pit arrangement supports a sister group relationship between Trochetia granulata Cordem. and T. blackburniana Bojer ex Baker and may be a new synapomorphy of the genus Trochetia. Finally, wood variability is evaluated in relation to geographic, climatic and biological data. Despite the juvenile nature of some of the specimens studied, we discuss how the habit, but also factors related to humidity, influence the variability observed in the Mascarene Dombeyoideae wood structure.

Download Full-text

Human Evolution

Notes for a Short Course: Studies in Geology ◽

10.1017/s0271164800000968 ◽

1984 ◽

Vol 8 ◽

pp. 182-198

Author(s):

Catherine Badgley

Keyword(s):

Human Evolution ◽

Evolutionary History ◽

Pan Paniscus ◽

Homo Sapiens ◽

Great Apes ◽

Sister Group ◽

The Family ◽

History Of ◽

Living Species ◽

Single Living

The evolutionary history of humans is well understood in outline, compared to that of many other groups of mammals. But human evolution remains enigmatic in its details, and these are compelling both scientifically and personally because they relate to the biological uniqueness of humans. Humans are placed in the primate family Hominidae, which, in traditional classifications, contains a single living species, Homo sapiens. The closest living relatives of humans are great apes: the chimpanzees Pan paniscus and Pan troglodytes, the gorilla Gorilla gorilla, and the orangutan Pongo pygmaeus. These apes have traditionally been placed in the family Pongidae as the sister group of Hominidae. Living Hominidae and Pongidae, together with Hylobatidae (gibbons) comprise the modern representatives of the primate suborder Hominoidea.

Download Full-text