A new phosphatized ophiuroid from the lower Triassic of Nevada and its position in the evolutionary history of the Ophiuroidea (Echinodermata)

The Lower Triassic fossil record of brittle stars is relatively rich, yet most records published to date are based on poorly preserved or insufficiently known fossils. This hampers exhaustive morphological analyses, comparison with recent relatives or inclusion of Early Triassic ophiuroid taxa in phylogenetic estimates. Here, we describe a new ophiuroid from the Lower Triassic of Nevada, preserved as phosphatized skeletal parts and assigned to the new taxon Ophiosuperstes praeparvus gen. et sp. nov Maxwell, V. & Pruss. S.B. This unusual preservation of the fossils allowed for acid-extraction of an entire suite of dissociated skeletal parts, including lateral arm plates, ventral arm plates, vertebrae and various disk plates, thus unlocking sufficient morphological information to explore the phylogenetic position of the new taxon. Bayesian phylogenetic inference suggests a basalmost position of O. praeparvus within the Ophintegrida, sister to all other sampled members of that superorder. The existence of coeval but more derived ophiuroids suggests that O. praeparvus probably represents a member of a more ancient stem ophintegrid group persisting into the Early Triassic.

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A new early-branching armoured dinosaur from the Lower Jurassic of southwestern China

10.1101/2021.11.24.469951 ◽

2021 ◽

Author(s):

Xi Yao ◽

Paul Barrett ◽

Lei Yang ◽

Xing Xu ◽

Shundong Bi

Keyword(s):

Fossil Record ◽

Evolutionary History ◽

Yunnan Province ◽

Morphological Diversity ◽

Lower Jurassic ◽

Early Jurassic ◽

New Taxon ◽

Unique Combination ◽

Geographic Spread ◽

History Of

The early evolutionary history of the armoured dinosaurs (Thyreophora) is obscured by its patchily distributed fossil record and by conflicting views on the relationships of its Early Jurassic representatives. Here, we describe an early-diverging thyreophoran from the Lower Jurassic Fengjiahe Formation of Yunnan Province, China, on the basis of an associated partial skeleton that includes skull, axial, limb and armour elements. It can be diagnosed as a new taxon based on numerous cranial and postcranial autapomorphies and is further distinguished from all other thyreophorans by a unique combination of character states. Although the robust postcranium is similar to that of more deeply nested ankylosaurs and stegosaurs, phylogenetic analysis recovers it as either the sister taxon of Emausaurus or of the clade Scelidosaurus and Eurypoda. This new taxon, Yuxisaurus kopchicki, represents the first valid thyreophoran dinosaur to be described from the Early Jurassic of Asia and confirms the rapid geographic spread and diversification of the clade after its first appearance in the Hettangian. Its heavy build and distinctive armour also hint at previously unrealised morphological diversity early in the clade history.

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The palate and choanae structure of theSusisuchusanatoceps(Crocodyliformes, Eusuchia): phylogenetic implications

PeerJ ◽

10.7717/peerj.5372 ◽

2018 ◽

Vol 6 ◽

pp. e5372 ◽

Cited By ~ 6

Author(s):

Karla J. Leite ◽

Daniel C. Fortier

Keyword(s):

Lower Cretaceous ◽

Fossil Record ◽

Evolutionary History ◽

Morphological Changes ◽

Ventral View ◽

Structural Evolution ◽

Sister Group ◽

Phylogenetic Position ◽

Phylogenetic Implications ◽

History Of

Crocodyliformes is a group with a broad fossil record, in which several morphological changes have been documented. Among known transformations the most iconic is perhaps the series of changes seen in the structural evolution of the choanae. The change in the position of the choanae was important during the evolutionary history of the Crocodyliformes. This structure is relevant in the phylogenetic position of many crocodyliforms. The new skull ofSusisuchus anatocepsfrom the Crato Formation of the Santana Group (Lower Cretaceous) is described and the preservation in the ventral view allows character encoding not yet observed for the species. The new specimen shows a typical eusuchian palate forSusisuchus anatoceps, in which the choana is fully enclosed by the pterygoid. The Susisuchidae clade has been placed in different phylogenetic positions: as a sister group of Eusuchia, advanced Neosuchia and in Eusuchia. InIsisfordiathere are reports that the choana of this taxon is or is not fully enclosed by the pterygoid. The encoding of the ventral characters ofS.anatocepsplaces Susisuchidae in Eusuchia. However, this position must be further studied, since the matrices showed fragility in the reconstitution of the Neosuchia–Eusuchia transition.

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Xiphosurid from the Tournaisian (Carboniferous) of Scotland confirms deep origin of Limuloidea

Scientific Reports ◽

10.1038/s41598-019-53442-5 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 7

Author(s):

Russell D. C. Bicknell ◽

Stephen Pates

Keyword(s):

Fossil Record ◽

Evolutionary History ◽

Horseshoe Crab ◽

New Taxon ◽

Geometric Morphometric ◽

Lower Carboniferous ◽

Morphometric Analyses ◽

Lower Ordovician ◽

Horseshoe Crabs ◽

History Of

AbstractHorseshoe crabs are archetypal marine chelicerates with a fossil record extending from the Lower Ordovician to today. The major horseshoe crab groups are thought to have arisen in the middle to late Palaeozoic. Here we present the oldest known limuloid from the lower Carboniferous (Tournaisian stage, c. 350 million years ago) of Scotland: Albalimulus bottoni gen. et sp. nov. A comprehensive phylogenetic analysis supports the placement of A. bottoni as a representative of the extant family Limulidae and 100 million years older than any other limulid taxon. The use of geometric morphometric analyses corroborate the erection of the new taxon and illustrates the exploitation of morphospace by xiphosurids. This new taxon highlights the complex evolutionary history of xiphosurids and the importance of documenting these unique Palaeozoic individuals.

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The first substantive evidence of Utatsusaurus (Ichthyopterygia) from the Sulphur Mountain Formation (Lower–Middle Triassic) of British Columbia, Canada: a skull roof description in comparison with other early taxa

Canadian Journal of Earth Sciences ◽

10.1139/cjes-2013-0185 ◽

2014 ◽

Vol 51 (2) ◽

pp. 180-185 ◽

Cited By ~ 4

Author(s):

Robin S. Cuthbertson ◽

Anthony P. Russell ◽

Jason S. Anderson

Keyword(s):

British Columbia ◽

Evolutionary History ◽

Middle Triassic ◽

Lower Triassic ◽

New Taxon ◽

Skull Roof ◽

History Of

We describe the skull roof anatomy of PRPRC 2007.08.81, a new specimen of late Olenekian (Spathian) ichthyopterygian from the Vega-Phroso Siltstone Member of the Sulphur Mountain Formation of British Columbia, Canada. Based on the presence of a well-developed anterolateral prefrontal process, parietal that is deeply excavated along its posteromedial margin, and skull roof sutural patterns, PRPRC 2007.08.81 closely resembles other Olenekian forms such as Utatsusaurus, Grippia, Chaohusaurus, and Gulosaurus (a new taxon recently described from British Columbia, Canada). However, due to their shared apomorphic supratemporal terrace morphology, PRPRC 2007.08.81 is identified as Utatsusaurus sp. With the only other known conclusive Utatsusaurus material retrieved from the Osawa Formation (Lower Triassic) of Japan, the broad palaeogeographic distribution of this taxon suggests a radiation event for Ichthyopterygia occurring prior to the latter part of the Olenekian. However, despite this inference, the palaeogeographic origin of Ichthyopterygia continues to be unclear; only the acquisition and interpretation of additional chronologically early ichthyopterygian material will resolve the early evolutionary history of this group.

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Nephromyces represents a diverse and novel lineage of the Apicomplexa that has retained apicoplasts

Genome Biology and Evolution ◽

10.1093/gbe/evz155 ◽

2019 ◽

Cited By ~ 4

Author(s):

Sergio A Muñoz-Gómez ◽

Keira Durnin ◽

Laura Eme ◽

Christopher Paight ◽

Christopher E Lane ◽

...

Keyword(s):

Life Style ◽

Metabolic Pathways ◽

Evolutionary History ◽

Phylogenetic Analyses ◽

Phylogenetic Position ◽

Biosynthetic Pathways ◽

History Of ◽

Sea Squirts ◽

Shed Light ◽

Apicoplast Genome

Abstract A most interesting exception within the parasitic Apicomplexa is Nephromyces, an extracellular, probably mutualistic, endosymbiont found living inside molgulid ascidian tunicates (i.e., sea squirts). Even though Nephromyces is now known to be an apicomplexan, many other questions about its nature remain unanswered. To gain further insights into the biology and evolutionary history of this unusual apicomplexan, we aimed to (1) find the precise phylogenetic position of Nephromyces within the Apicomplexa, (2) search for the apicoplast genome of Nephromyces, and (3) infer the major metabolic pathways in the apicoplast of Nephromyces. To do this, we sequenced a metagenome and a metatranscriptome from the molgulid renal sac, the specialized habitat where Nephromyces thrives. Our phylogenetic analyses of conserved nucleus-encoded genes robustly suggest that Nephromyces is a novel lineage sister to the Hematozoa, which comprises both the Haemosporidia (e.g., Plasmodium) and the Piroplasmida (e.g., Babesia and Theileria). Furthermore, a survey of the renal sac metagenome revealed 13 small contigs that closely resemble the genomes of the non-photosynthetic reduced plastids, or apicoplasts, of other apicomplexans. We show that these apicoplast genomes correspond to a diverse set of most closely related but genetically divergent Nephromyces lineages that co-inhabit a single tunicate host. In addition, the apicoplast of Nephromyces appears to have retained all biosynthetic pathways inferred to have been ancestral to parasitic apicomplexans. Our results shed light on the evolutionary history of the only probably mutualistic apicomplexan known, Nephromyces, and provide context for a better understanding of its life style and intricate symbiosis.

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The postcranial skeleton, phylogenetic position, and probable lifestyle of the Early Triassic reptile Procolophon trigoniceps

Canadian Journal of Earth Sciences ◽

10.1139/e02-082 ◽

2003 ◽

Vol 40 (4) ◽

pp. 527-556 ◽

Cited By ~ 44

Author(s):

Michael deBraga

Keyword(s):

South Africa ◽

Morphological Study ◽

Lower Triassic ◽

Sister Group ◽

Phylogenetic Position ◽

Sister Group Relationship ◽

Early Triassic ◽

Postcranial Skeleton ◽

Sister Clade ◽

Key Innovations

A morphological study of the postcranial skeleton of Procolophon trigoniceps from the Lower Triassic of South Africa and Antarctica is undertaken. Procolophon shares a sister-group relationship with the procolophonid Tichvinskia from the Lower Triassic of Russia and is a basal member of Procolophonidae. This clade also includes the enigmatic taxon Sclerosaurus, believed most recently to be a pareiasaur relative. Owenettids form a separate lineage from Procolophonidae and are predominantly restricted to the Permian of both South Africa and Madagascar. A phylogenetically based assessment is considered, in which specialized modern taxa (sand lizards) are compared to their nonfossorial sister clade, allowing for "key innovations" to be identified. A similar comparison between owenettids and procolophonids reveals a number of apparent "key innovations" within procolophonids that are suggestive of a burrowing lifestyle for Procolophon.

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Phylogenetic position and evolutionary history of the turtle and whale barnacles (Cirripedia: Balanomorpha: Coronuloidea)

Molecular Phylogenetics and Evolution ◽

10.1016/j.ympev.2012.12.018 ◽

2013 ◽

Vol 67 (1) ◽

pp. 9-14 ◽

Cited By ~ 16

Author(s):

Ryota Hayashi ◽

Benny K.K. Chan ◽

Noa Simon-Blecher ◽

Hiromi Watanabe ◽

Tamar Guy-Haim ◽

...

Keyword(s):

Evolutionary History ◽

Phylogenetic Position ◽

History Of

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A fossil record of land plant origins from charophyte algae

Science ◽

10.1126/science.abj2927 ◽

2021 ◽

Vol 373 (6556) ◽

pp. 792-796 ◽

Cited By ~ 1

Author(s):

Paul K. Strother ◽

Clinton Foster

Keyword(s):

Fossil Record ◽

Evolutionary History ◽

Phylogenetic Signal ◽

Land Plant ◽

Fossil Plants ◽

Fossil Plant ◽

Molecular Phylogenetic ◽

History Of ◽

Time Gap ◽

Evolutionary Continuity

Molecular time trees indicating that embryophytes originated around 500 million years ago (Ma) during the Cambrian are at odds with the record of fossil plants, which first appear in the mid-Silurian almost 80 million years later. This time gap has been attributed to a missing fossil plant record, but that attribution belies the case for fossil spores. Here, we describe a Tremadocian (Early Ordovician, about 480 Ma) assemblage with elements of both Cambrian and younger embryophyte spores that provides a new level of evolutionary continuity between embryophytes and their algal ancestors. This finding suggests that the molecular phylogenetic signal retains a latent evolutionary history of the acquisition of the embryophytic developmental genome, a history that perhaps began during Ediacaran-Cambrian time but was not completed until the mid-Silurian (about 430 Ma).

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Experimental degradation of helicoidal photonic nanostructures in scarab beetles (Coleoptera: Scarabaeidae): implications for the identification of circularly polarizing cuticle in the fossil record

Journal of The Royal Society Interface ◽

10.1098/rsif.2018.0560 ◽

2018 ◽

Vol 15 (148) ◽

pp. 20180560 ◽

Cited By ~ 3

Author(s):

Giliane P. Odin ◽

Maria E. McNamara ◽

Hans Arwin ◽

Kenneth Järrendahl

Keyword(s):

Uric Acid ◽

Fossil Record ◽

Evolutionary History ◽

Polarized Light ◽

Circularly Polarized Light ◽

Circularly Polarized ◽

Alkaline Conditions ◽

History Of ◽

Diagenetic History ◽

Scarab Beetles

Scarab beetles (Coleoptera: Scarabaeidae) can exhibit striking colours produced by pigments and/or nanostructures. The latter include helicoidal (Bouligand) structures that can generate circularly polarized light. These have a cryptic evolutionary history in part because fossil examples are unknown. This suggests either a real biological signal, i.e. that Bouligand structures did not evolve until recently, or a taphonomic signal, i.e. that conditions during the fossilization process were not conducive to their preservation. We address this issue by experimentally degrading circularly polarizing cuticle of modern scarab beetles to test the relative roles of decay, maturation and taxonomy in controlling preservation. The results reveal that Bouligand structures have the potential to survive fossilization, but preservation is controlled by taxonomy and the diagenetic history of specimens. Further, cuticle of specific genus ( Chrysina ) is particularly decay-prone in alkaline conditions; this may relate to the presence of certain compounds, e.g. uric acid, in the cuticle of these taxa.

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Three new Cenomanian conifers from El Chango (Chiapas, Mexico) offer a snapshot of the geographic mosaic of the Mesozoic conifer decline

10.1101/2021.09.01.458614 ◽

2021 ◽

Author(s):

Ixchel Gonzalez-Ramirez ◽

Sergio RS Cevallos-Ferriz ◽

Carl Rothfels

Keyword(s):

Evolutionary History ◽

Mixed Forest ◽

Freshwater Ecosystems ◽

Total Evidence ◽

Morphological Data ◽

Phylogenetic Position ◽

Dominant Group ◽

Geographic Mosaic ◽

History Of ◽

Rare Opportunity

Premise of study: El Chango is a recently discovered quarry that contains extremely well preserved fossils. The Cenomanian age of the locality corresponds to a time when the global flora was transitioning from gymnosperm- to angiosperm-dominated, yet conifers predominate in this locality. These fossils thus provide a rare opportunity to understand the replacement of conifers by angiosperms as the dominant group of plants. Methods: We collected material from El Chango in annual expeditions (2010 to 2014). We selected the three most abundant and best preserved conifer morphotypes and conducted a total-evidence (i.e., including molecular and morphological data) phylogenetic analysis of a sample of 72 extant conifer species plus the three fossils. We use these results to inform our taxonomic decisions. Results: We obtained four equally most-parsimonious trees (consistency index = 44.1%, retention index = 78.8%). Despite ambiguous relationships among some extant taxa, the three fossil conifers had the same phylogenetic position in all four most parsimonious trees; we describe these species as new: Sequoiadendron helicalancifolium sp. nov. (Cupressaceae), and Microcachrys rhomboidea sp. nov. and Dacrydium bifoliosus sp. nov (Podocarpaceae). The ecosystem is interpreted as a coastal humid mixed forest. Conclusions: Our findings contribute to the understanding of Cenomanian equatorialregions, and support the hypothesis of a geographically and ecologically structured rise of angiosperms, with conifers remaining dominant in brackish-water and angiosperms becoming dominant in freshwater-ecosystems. These fossils fill in gaps in the evolutionary history of lineages like Microcachrys, which we demonstrate occurred in the Northern hemisphere before becoming restricted to its current range (Tasmania).

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