Diversification patterns based on the largest morphological phylogenetic analysis of Pleurodira (original) (raw)
Related papers
Biological Journal of The Linnean Society, 1999
Aspects of the phylogeny of pleurodiran turtles are contentious, particularly within the Chelidae. Morphological analyses group the long-necked Australasian Chelodina and the long-necked South American Chelus and Hydromedusa into a single clade, suggesting a common derived origin of the long neck and associated habits that predated the separation of Australia from South America. In contrast, published analyses of 12SrRNA and cytochrome b sequences suggest that the long-necked Chelodina are more closely related to the short-necked Australasian genera than to either Chelus or Hydromedusa. This paper adds partial sequences of 16S rRNA and CO1 mitochondrial genes and partial sequences of the nuclear oncogene c-mos to test a range of previous hypotheses on the phylogenetic relationships among chelid turtles. In total, 1382 nucleotides were available for each of 25 taxa after elimination of ambiguously aligned regions. These taxa included representatives of all the genera of the turtle families Chelidae and Pelomedusidae, the three sub-genera of Phrynops, and recognized sub-generic groups of Elseya and Chelodina. Of the four genes examined, 12S rRNA was the most informative, followed by c-mos with 16S rRNA and CO1 the least informative. The molecular data support the currently accepted arrangement for pelomedusid genera, that is, a sister relationship between the African Pelusios and Pelomedusa and a clade comprising the South American Peltoceplhalus and Podocnemis with the Madagascan Erymnochelys. However, there is also support for Erymnochelys and Podocnemis as sister taxa to the exclusion of Peltocephalus (bootstrap values of 69–80%) which is at odds with the most commonly accepted arrangement. The South American chelids are monophyletic (76–82%). This clade includes the long-necked Chelus and Hydromedusa, but excludes the Australasian long-necked Chelodina. Furthermore, the South American long-necked chelids are not themselves monophyletic, with 98–100% bootstrap values for the node supporting Chelus and the remaining South American chelids to the exclusion of Hydromedusa. Hence, the hypothesis of a monophyletic grouping of the long-necked genera of South America and Australasia is not supported by the molecular data. Although reciprocal monophyly of the South American and Australasian chelid faunas was the most likely and the most parsimonious arrangement in all but one analysis, bootstrap support for the monophyly of the Australasian chelids was low (52–66%). The South American chelids, Chelodina and the short-necked Australasian chelids form an unresolved trichotomy. The genera Phrynops and Elseya are paraphyletic, leading to a recommendation to elevate the three sub-genera of Phrynops to generic status and support for previous suggestions to erect a new genus for Elseya latistermum and close relatives. A revised classification of the extant Pleurodira is presented, consistent with the phylogenetic relationships that emerge from this study.
Notoemys zapatocaensis is the youngest representative of the Platychelyidae, a group of Late Jurassic-Early Cretaceous pleurodires. Here we describe two new specimens of this species represented by a partial carapace and a nearly complete articulated shell. Notoemys zapatocaensis is different from other platychelyid turtles in having: (1) two fairly reduced lateral tuberosities on the margin of the anterior plastral lobe, (2) a shallow notch on the posterolateral margin of the epiplastra, giving a convex posterolateral edge to this bone, (3) gular scales that are rectangular in shape and much wider than long, (4) a long intergular scale that has a slight medial contact with the pectorals, resulting in a complete separation of the humeral scales, (5) a central plastral fontanelle that projects posteriorly into the xiphiplastral region, (6) a very small marginal 3, (7) a slightly shorter neural 1 than neural 2, with an exclusive lateral contact with costal 1, resulting in a complete separation of neural 2 and costal 1, (8) narrower vertebral scales, and (9) peripheral 3 lacking a posteromedial contact with costal 2. Phylogenetic analysis indicates that N. zapatocaensis is a sister taxon of N. oxfordiensis, and that Proterochersis robusta can be resolved in two different positions in the testudines tree: (1) with Odontochelys semitestacea based on the fact that both taxa share two mesoplastra meeting at midline, or (2) as the most basal pleurodire, based on a suture articulation of pelvis to shell. Anal notch shape and potentially fontanelle size are indicators of sexual dimorphism in platychelyids.
Taxonomy and phylogeny in the earliest diverging pleurocarps: square holes and bifurcating pegs
The Bryologist, 2007
The extant members of the earliest diverging pleurocarpous moss lineages comprise few species but span a wide range of structural and molecular diversity, most of it restricted to temperate and high-altitude tropical forests in the Southern Hemisphere. We present the most comprehensive molecular phylogenetic study of these lineages to date, based on parsimony and Bayesian analyses of four regions from the chloroplast and mitochondrial genomes. In addition to corroborating the findings of parsimony methods in this and previous studies, the results of heterogeneous Bayesian analyses provide strong support for sub-topologies that are also consistently found under parsimony, but are rarely well supported. Careful model specification and investigation of potential sources of error increase confidence in the Bayesian results, which provide the basis for a substantially revised classification reflecting the best currently available hypothesis of evolutionary history. The genera previously classified in the Rhizogoniaceae, together with Orthodontium, Orthodontopsis, Aulacomnium and Calomnion, are recognized in three families, the Orthodontiaceae, Rhizogoniaceae and Aulacomniaceae, and three monofamilial orders, the Orthodontiales ord. nov., Rhizogoniales and Aulacomniales ord. nov. Many of the species previously recognized in Hypnodendron are placed in Sciadocladus, Touwiodendron gen. nov., Dendro-hypnum or Mniodendron. These genera, with the exception of Sciadocladus, are placed in the Hypnodendraceae together with Spiridens, Franciella, Cyrtopus and Bescherellia. Braithwaitea is excluded from the Hypnodendraceae and recognized in the monogeneric Braithwaiteaceae fam. nov., while Sciadocladus is placed with Pterobryella and
2018
Morphology, or shapes, particularly of bones, is important for understanding how animals vary and, therefore, for understanding diversity. Comparison of morphology in animals can be used to make inferences on fossil organisms. At its base, fossil specimens are described and compared with other fossil and modern specimens, often to determine if they represent a new and distinct species, thereby increasing observed biodiversity through time. Dromaeosaurids (family Dromaeosauridae) are a group of dynamic, swift predatory dinosaurs, that have a sparse fossil record, particularly at the time of their extinction near the Cretaceous-Paleogene boundary. A recently recovered specimen from the latest Cretaceous of New Mexico represents a new genus and species and is the first diagnostic dromaeosaurid from the Maastrichtian of the southern United States (southern Laramidia). The specimen also reveals aspects of this dinosaurs behavior, including potential wounds or injuries consistent with an active predatory lifestyle, features that would have made it agile, and the presence of feathers on its forelimbs. The evolutionary relationships of this dinosaur were explored through phylogenetic analysis and shows multiple lineages of these dinosaurs at the end of the Cretaceous in North America. Additionally, the Maastrichtian members of these dinosaurs would have also been living in the same environments as the largest terrestrial predators known, the tyrannosaurids, with different species in the north and south living alongside different tyrannosaurid species, creating complex ecosystems with different sized predators presumably utilizing different predatory methods. Emydids (family Emydidae) are the most diverse and widespread family of turtles in the New World. Their fossil record is relatively well known, but more complete fossils are less common and little work has been done to understand the relationships of potential fossil members. New species within both subfamilies (Deirochelyinae and Emydinae) from approximately 5 million years ago increase our knowledge of the past biodiversity of the group. A new painted turtle helps show how Chrysemys has migrated through time and part of these biogeographic changes are controlled by temperature and climate conditions. A new species of Emydoidea represents the southern-most occurrence of the genus and suggests the physiological requirements of the species have changed through time. A new species of Terrapene shows features consistent with an aquatic or semi-aquatic lifestyle, and its position basally within the genus lends further credence to the hypothesis that the genus evolved from aquatic or semiaquatic ancestors and has evolved to become more terrestrial through time. The new species also help researchers better understand previously known fossil species. Several fossil species considered to represent Chrysemys are found to be basally within the subfamily and potentially outside Chrysemys. Emydoidea lies phylogenetically close to Emys and is part of a clade of emydine turtles that can at least partially close their shells. Features of stem Terrapene species suggest features of T. ornata are basal and further suggests terrestrially has evolved multiple times in the genus or that there have been multiple reinvasions of the water. These studies look at morphological variation to determine the distinct nature of several new fossil species and use phylogenetic analyses to hypothesize evolutionary relationships. This information can be used to make inferences of the direct groups studied and closely related groups, but also can be used to investigate ancient ecosystems and local and regional habitats and climates, along with more generalized larger-scale conditions. These continue to add to our knowledge of biodiversity and increases the information and data we have to use toward further future studies as well.
Placoderm diversity and evolution
Bulletin Du Museum National D Histoire Naturelle Section C Sciences De La Terre Paleontologie Geologie Mineralogie, 1995
Stratigraphic ranges for 720 placoderm taxa are presented and diversity patterns are charac terized for six monophyletic placoderm orders as well as for other Devonian and Mississippian gnathostomes. Analysis at the level of substage is critical for the recognition of placoderm subclade diversity patterns. The current temporal and taxonomic resolution of individual placoderm taxa is sufficient to provide a clear picture of diversity independent of the level of resolution selected for screening data. Analysis of all available data provides the best picture of placoderm diversity. Current hypotheses of arthrodiran competitive displacement represent global patterns and require careful consideration of patterns of phylogeny, geographic distribution, and ecological sympatry. These considerations provide alternative interpretations of timing of events and influence the analyses of alternative hypotheses of biological interactions (competitive or opportunistic replacements or chance). Pachyosteomorph arthrodiran diversity may be correlated with morphological evolution related to adap tations associated with feeding and locomotion. Gnathostome diversity suggests that Devonian extinction episodes are not ubiquitous events with clades showing different responses to three putative Upper Devonian extinctions (Givetian-Frasnian. Frasnian-Famennian, and Famennian-Tournaisian). The Frasnian-Famennian extinction event had a significant effect on placoderms. This event may have reduced the numbers of placoderms sufficiently to provide a "window of opportunity" for the early radiation of actinopterygians and chondrichthyans. During the Famennian there is evidence for predator-prey relationships and potential competition for resources among sur viving placoderms and other gnathostomes. These biological interactions are coincident with an inverse relation ship between placoderm diversity patterns and those for actinopterygians and chondrichthyans. This coincidence suggests that the extinction of placoderms may be attributed to competitive displacement although opportunistic replacement following the putative Famennian-Tournaisian extinction event remains as an alternative explanation.
Phylogeny, biogeography and diversification patterns of side-necked turtles (Testudines: Pleurodira)
Royal Society open science, 2018
Pleurodires or side-necked turtles are today restricted to freshwater environments of South America, Africa-Madagascar and Australia, but in the past they were distributed much more broadly, being found also on Eurasia, India and North America, and marine environments. Two hypotheses were proposed to explain this distribution; in the first, vicariance would have shaped the current geographical distribution and, in the second, extinctions constrained a previously widespread distribution. Here, we aim to reconstruct pleurodiran biogeographic history and diversification patterns based on a new phylogenetic hypothesis recovered from the analysis of the largest morphological dataset yet compiled for the lineage, testing which biogeographical process prevailed during its evolutionary history. The resulting topology generally agrees with previous hypotheses of the group and shows that most diversification shifts were related to the exploration of new niches, e.g. littoral or marine radiati...
Phylogenetic Relationships of Pleuronectiformes Based on Molecular Evidence
Copeia, 2002
Phylogenetic analyses based on nucleotide sequence data of the 12S and 16S mitochondrial ribosomal genes were performed for representatives of the Pleuronectiformes (flatfishes). Two parsimony analyses with percomorphs and basal acanthopterygians designated as outgroups were conducted; equal weighting of all nucleotides and loop regions analyzed for transversions only. A bayesian analysis was performed under the likelihood model TrN؉I؉⌫. A monophyletic Pleuronectiformes was resolved in all analyses. Results are consistent with the current higher level classification, recognizing the suborders Psettodoidei and Pleuronectoidei. Psettodoidei consists of a single family, Psettodidae, that is sister to all other flatfishes. Within the Pleuronectoidei three clades are identified. Bothids plus paralichthyids (in part) form a clade in all analyses. A solelike clade containing citharids, cynoglossids, samarids, soleids, Trinectes (Achiridae), and Poecilopsetta (Poecilsopsettidae), is identified in the parsimony analyses. However, a solelike clade was not recovered in the bayesian analysis. A flounderlike clade is identified containing Pleuronectidae and Paralichthyidae (in part) in all analyses. The position of Scophthalmus (Scophthalmidae) differed among all analyses. The results further support the conclusion that eye position is not a useful source of information for the classification of flatfishes. This study provides a new framework for future studies.
The extinct Stereogenyina turtles form a relatively diverse Podocnemididae lineage, with twelve described and phylogenetically positioned species. They are characterized by a wide geographic and temporal range, from the Eocene of Africa to the Pleistocene of Southeast Asia, and a peculiar palate morphology, with a secondary palate that is unique among side-necked turtles. Here, we describe a new Stereogenyina species, based on an almost complete skull from the middle Miocene Capadare Formation, of Venezuela. A new phylogenetic analysis supports the assignment of the new species to the genus Bairdemys. Based on geometric morphometrics analyses, we related the development of the stereogenyin secondary palate with the acquisition of a durophagous diet. Based on a review of the sedimentary environments where their fossils are found, we also propose that stereogenyins were a marine radiation of podocnemidid turtles, as corroborated by previous studies of fossil eggs and limb morphology. These two inferences allowed us to hypothesize that stereogenyins occupied an ecological niche similar to that of the extant Carettini sea turtles, and that the rise of the latter group may be related to the Stereogenyina diversity fall in the end of the Miocene. Subjects Paleontology, Taxonomy How to cite this article Ferreira et al. (2015), The last marine pelomedusoids (Testudines: Pleurodira): a new species of Bairdemys and the paleoecology of Stereogenyina.