scholarly journals The developmental biology of Charnia and the eumetazoan affinity of the Ediacaran rangeomorphs

2021 ◽  
Vol 7 (30) ◽  
pp. eabe0291
Author(s):  
Frances S. Dunn ◽  
Alexander G. Liu ◽  
Dmitriy V. Grazhdankin ◽  
Philip Vixseboxse ◽  
Joseph Flannery-Sutherland ◽  
...  
Keyword(s):  
Developmental Biology ◽  
Phylogenetic Analysis ◽  
Direct Evidence ◽  
Animal Evolution ◽  
Fossil Evidence ◽  
Evolutionary Emergence

Molecular timescales estimate that early animal lineages diverged tens of millions of years before their earliest unequivocal fossil evidence. The Ediacaran macrobiota (~574 to 538 million years ago) are largely eschewed from this debate, primarily due to their extreme phylogenetic uncertainty, but remain germane. We characterize the development of Charnia masoni and establish the affinity of rangeomorphs, among the oldest and most enigmatic components of the Ediacaran macrobiota. We provide the first direct evidence for the internal interconnected nature of rangeomorphs and show that Charnia was constructed of repeated branches that derived successively from pre-existing branches. We find homology and rationalize morphogenesis between disparate rangeomorph taxa, before producing a phylogenetic analysis, resolving Charnia as a stem-eumetazoan and expanding the anatomical disparity of that group to include a long-extinct bodyplan. These data bring competing records of early animal evolution into closer agreement, reformulating our understanding of the evolutionary emergence of animal bodyplans.

scholarly journals Black spicules from a new interstitial opheliid polychaete Thoracophelia minuta sp. nov. (Annelida: Opheliidae)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Naoto Jimi ◽  
Shinta Fujimoto ◽  
Mami Takehara ◽  
Satoshi Imura
Keyword(s):  
Developmental Biology ◽  
Phylogenetic Analysis ◽  
New Species ◽  
Morphological Diversity ◽  
The Body ◽  
Evolutionary Significance ◽  
Research Subject ◽  
Ecological Diversity ◽  
Coelomic Cavity ◽  
Molecular Phylogenetic

AbstractThe phylum Annelida exhibits high morphological diversity coupled with its extensive ecological diversity, and the process of its evolution has been an attractive research subject for many researchers. Its representatives are also extensively studied in fields of ecology and developmental biology and important in many other biology related disciplines. The study of biomineralisation is one of them. Some annelid groups are well known to form calcified tubes but other forms of biomineralisation are also known. Herein, we report a new interstitial annelid species with black spicules, Thoracophelia minuta sp. nov., from Yoichi, Hokkaido, Japan. Spicules are minute calcium carbonate inclusions found across the body and in this new species, numerous black rod-like inclusions of calcium-rich composition are distributed in the coelomic cavity. The new species can be distinguished from other known species of the genus by these conspicuous spicules, shape of branchiae and body formula. Further, the new species’ body size is apparently smaller than its congeners. Based on our molecular phylogenetic analysis using 18S and 28S sequences, we discuss the evolutionary significance of the new species’ spicules and also the species' progenetic origin.

Asymmetry in the fossil record

2005 ◽  
Vol 13 (S2) ◽  
pp. 135-143 ◽  
Author(s):  
LOREN E. BABCOCK
Keyword(s):  
Fossil Record ◽  
Direct Evidence ◽  
Directional Asymmetry ◽  
Fundamental Aspect ◽  
Lateral Asymmetry ◽  
Morphological Asymmetry ◽  
Fossil Evidence ◽  
Behavioural Asymmetries ◽  
Life On Earth ◽  
Body Fossil

Asymmetry is a fundamental aspect of the biology of all organisms, and has a deep evolutionary history. The fossil record contains evidence of both morphological and behavioural asymmetries. Morphological asymmetry is most commonly expressed as conspicuous, directional asymmetry (either lateral asymmetry or spiral asymmetry) in body fossils. Few examples of fluctuating asymmetry, a form of subtle asymmetry, have been documented from fossils. Body fossil evidence indicates that morphological asymmetry dates to the time of the appearance of the first life on Earth (Archaean Eon). Behavioural asymmetry can be assumed to have been concomitant with conspicuous morphological asymmetry, but more direct evidence is in the form of trace fossils. Trace fossil evidence suggests that behavioural asymmetry, including nervous system lateralization, was in existence by the beginning of the Palaeozoic Era.

scholarly journals An early Cambrian polyp reveals an anemone-like ancestor for medusozoan cnidarians

2021 ◽  
Author(s):  
Yang Zhao ◽  
Luke Parry ◽  
Jakob Vinther ◽  
Frances S. Dunn ◽  
Yujing Li ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Fossil Record ◽  
Soft Tissues ◽  
Common Ancestor ◽  
Last Common Ancestor ◽  
Early Cambrian ◽  
Crown Group ◽  
Sessile Polyp ◽  
Animal Evolution ◽  
Chengjiang Biota

Extant cnidarians are a disparate phylum of non-bilaterians and their diploblastic body plan represents a key step in animal evolution. Anthozoans (anemones, corals) are benthic polyps, while adult medusozoans (jellyfishes) are dominantly pelagic medusae. A sessile polyp is present in both groups and is widely conceived as the ancestral form of their last common ancestor. However, the nature and anatomy of this ancestral polyp, particularly of medusozoans, are controversial, owing to the divergent body plans of both groups in the extant lineages and the rarity of medusozoan soft tissues in the fossil record. Here we redescribe the enigmatic Conicula striata Luo et Hu from the early Cambrian Chengjiang biota, south China, which has previously been interpreted as a polyp, lophophorate or deuterostome. We show that C. striata possessed features of both anthozoans and medusozoans. Its stalked polyp and fully encasing conical, annulated organic skeleton (periderm) are features of medusozoans. However, the gut is partitioned by ~28 mesenteries, and has a tubular pharynx, resembling anthozoans. Our phylogenetic analysis recovers C. striata as a stem medusozoan, indicating that the enormously diverse medusozoans were derived from an anemone-like ancestor, with the pharynx lost and number of mesenteries reduced prior to the origin of crown group Medusozoa.

Fossil butterflies, calibration points and the molecular clock (Lepidoptera: Papilionoidea)

Zootaxa ◽  
2017 ◽  
Vol 4270 (1) ◽  
pp. 1 ◽  
Author(s):  
RIENK DE JONG
Keyword(s):  
Phylogenetic Analysis ◽  
Phylogenetic Tree ◽  
Molecular Clock ◽  
Age Estimation ◽  
Direct Evidence ◽  
Divergence Times ◽  
Specific Information ◽  
Extant Species ◽  
Correct Determination

Fossil butterflies are extremely rare. Yet, they are the only direct evidence of the first appearance of particular characters and as such, they are crucial for calibrating a molecular clock, from which divergence ages are estimated. In turn, these estimates, in combination with paleogeographic information, are most important in paleobiogeographic considerations. The key issue here is the correct allocation of fossils on the phylogenetic tree from which the molecular clock is calibrated.The allocation of a fossil on a tree should be based on an apomorphic character found in a tree based on extant species, similar to the allocation of a new extant species. In practice, the latter is not done, at least not explicitly, on the basis of apomorphy, but rather on overall similarity or on a phylogenetic analysis, which is not possible for most butterfly fossils since they usually are very fragmentary. Characters most often preserved are in the venation of the wings. Therefore, special attention is given to possible apomorphies in venational characters in extant butterflies. For estimation of divergence times, not only the correct allocation of the fossil on the tree is important, but also the tree itself influences the outcome as well as the correct determination of the age of the fossil. These three aspects are discussed.        All known butterfly fossils, consisting of 49 taxa, are critically reviewed and their relationship to extant taxa is discussed as an aid for correctly calibrating a molecular clock for papilionoid Lepidoptera. In this context some aspects of age estimation and biogeographic conclusions are briefly mentioned in review. Specific information has been summarized in four appendices.

Testing the time axis of phylogenies

1995 ◽  
Vol 349 (1327) ◽  
pp. 5-10 ◽  
Keyword(s):  
Phylogenetic Analysis ◽  
Fossil Record ◽  
Direct Evidence ◽  
Phylogeny Reconstruction ◽  
Time Axis ◽  
Historical Events ◽  
Subsequent Evolution ◽  
The Past ◽  
Fossil Data

Fossils are not perfect materials for phylogenetic analysis because of problems of missing characters and missing taxa. However, fossils have three major advantages: (1) they give the only direct evidence of the order of acquisition of characters, (2) they frequently present character combinations not found in modern forms, and (3) they may allow the coding of characters that have been overwritten by subsequent evolution within a clade. There are three independent sources of evidence about sequences of historical events in evolution - morphological, molecular and stratigraphic - and these may be mutually cross- tested. Tests of the quality of the fossil record against morphological cladistic data show that (1) age and clade data on branching sequences generally agree, (2) knowledge of the fossil record has improved by 5% over the past 26 years of research, and (3) the fossil record of continental vertebrates is as good as that of (marine) echinoderms. Hence, systematists and evolutionary biologists may use fossil data with confidence in phylogeny reconstruction and to calibrate the time axis of phylogenies.

Fossils, homology, and “Phylogenetic Paleo-ontogeny”: a reassessment of primary posterior plate homologies among fossil and living crinoids with insights from developmental biology

Paleobiology ◽  
2015 ◽  
Vol 41 (4) ◽  
pp. 570-591 ◽  
Author(s):  
David F. Wright
Keyword(s):  
Developmental Biology ◽  
Phylogenetic Analysis ◽  
Phylogenetic Analyses ◽  
A Priori ◽  
Evolutionary Developmental Biology ◽  
Phylogeny Reconstruction ◽  
Phylogenetic Systematics ◽  
Developmental Patterns ◽  
Single Plate ◽  
Homology Recognition

AbstractPaleobiologists must propose a priori hypotheses of homology when conducting a phylogenetic analysis of extinct taxa. The distributions of such “primary” homologies among species are fundamental to phylogeny reconstruction because they reflect a prior belief in what constitutes comparable organismal elements and are the principal determinants of the outcome of phylogenetic analysis. Problems arise when fossil morphology presents seemingly equivocal hypotheses of homology, herein referred to as antinomies. In groups where homology recognition has been elusive, such as echinoderms, these problems are commonly accompanied by the presence (and persistence) of poor descriptive terminology in taxonomic literature that confounds an understanding of characters and stymy phylogenetic research. This paper combines fossil morphology, phylogenetic systematics, and insights from evolutionary developmental biology to outline a research program in Phylogenetic Paleo-ontogeny. A “paleo” ontogenetic approach to character analysis provides a logical basis for homology recognition and discerning patterns of character evolution in a phylogenetic context. To illustrate the utility of the paleo-ontogenetic approach, I present a reassessment of historically contentious plate homologies for “pan-cladid” crinoids (Cladida, Flexibilia, Articulata). Developmental patterns in living crinoids were combined with the fossil record of pan-cladid morphologies to investigate primary posterior plate homologies. Results suggest the sequence of morphologic transitions unfolding during the ontogeny of extant crinoids are developmental relics of their Paleozoic precursors. Developmental genetic modules controlling posterior plate development in pan-cladid crinoids have likely experienced considerable constraint for over 250 million years and limited morphologic diversity in the complexity of calyx characters. Future phylogenetic analyses of pan-cladids are recommended to consider the presence of a single plate in the posterior region homologous with the radianal, rather than the anal X, as is commonly assumed.

scholarly journals Detection of bluetongue virus in Culicoides spp. in southern Yunnan Province, China

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Ying Liang Duan ◽  
Le Li ◽  
Glenn Bellis ◽  
Zhen Xing Yang ◽  
Hua Chun Li
Keyword(s):  
Phylogenetic Analysis ◽  
Dna Sequences ◽  
Reverse Transcription ◽  
Bluetongue Virus ◽  
Yunnan Province ◽  
Direct Evidence ◽  
Light Trapping ◽  
Tropical Region ◽  
Fourth Report ◽  
Bluetongue Disease

Abstract Background Culicoides (Diptera: Ceratopogonidae) are vectors for many arboviruses. At least 20 species are considered as vectors or potential vectors of bluetongue virus (BTV) which cause bluetongue disease in ruminants. A BTV prevalence of 30–50% among cattle and goats in tropical southern Yunnan Province, China, prompted an investigation of the potential BTV vectors in this area. Methods Culicoides were collected by light trapping at three sites in the tropical region of Yunnan Province. Species were identified based on morphology and DNA sequences of cytochrome c oxidase subunit 1 (cox1). PCR and quantitative PCR following reverse transcription were used to test for the presence of BTV RNA in these specimens. Phylogenetic analysis was used to analyze the cox1 sequences of Culicoides specimens infected with BTV. Results Approximately 67,000 specimens of Culicoides were collected, of which 748 were tested for the presence of BTV. Five specimens, including two of Culicoides jacobsoni, one of C. tainanus and two of C. imicola, were identified as infected with BTV. No specimens of C. (subgenus Trithecoides) or C. oxystoma tested were positive for BTV infection. Conclusions To our knowledge this is the first report of C. jacobsoni as a potential BTV vector and the fourth report of an association between C. tainanus and BTV, as well as the first direct evidence of an association between BTV and C. imicola in Asia. A fourth potential cryptic species within C. tainanus was identified in this study. Further analysis is required to confirm the importance of C. jacobsoni and C. tainanus in BTV epidemiology in Asia.

scholarly journals Tikiguania and the antiquity of squamate reptiles (lizards and snakes)

2012 ◽  
Vol 8 (4) ◽  
pp. 665-669 ◽  
Author(s):  
Mark N. Hutchinson ◽  
Adam Skinner ◽  
Michael S. Y. Lee
Keyword(s):  
Phylogenetic Analysis ◽  
Molecular Data ◽  
Molecular Dating ◽  
Late Triassic ◽  
Squamate Reptiles ◽  
Lower Jaw ◽  
Fossil Evidence ◽  
Prominent Component ◽  
Late Tertiary ◽  
Morphological And Molecular Data

Tikiguania estesi is widely accepted to be the earliest member of Squamata, the reptile group that includes lizards and snakes. It is based on a lower jaw from the Late Triassic of India, described as a primitive lizard related to agamids and chamaeleons. However, Tikiguania is almost indistinguishable from living agamids; a combined phylogenetic analysis of morphological and molecular data places it with draconines, a prominent component of the modern Asian herpetofauna. It is unlikely that living agamids have retained the Tikiguania morphotype unchanged for over 216 Myr; it is much more conceivable that Tikiguania is a Quaternary or Late Tertiary agamid that was preserved in sediments derived from the Triassic beds that have a broad superficial exposure. This removes the only fossil evidence for lizards in the Triassic. Studies that have employed Tikiguana for evolutionary, biogeographical and molecular dating inferences need to be reassessed.

scholarly journals Molecular identification of severe fever with thrombocytopenia syndrome viruses from tick and bitten patient in Southeast China

2020 ◽  
Author(s):  
Yongxi Tong ◽  
qiujing wang ◽  
Yongfeng Fu ◽  
Shibo Li ◽  
Zhao Zhang ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Direct Evidence ◽  
Multiple Organ ◽  
Type B ◽  
Intermediate Hosts ◽  
Case Presentation ◽  
Southeast China ◽  
Direct Cross ◽  
Pathogen Diagnosis ◽  
Severe Fever

Abstract Background Severe fever and thrombocytopenia bunyavirus (SFTSV) infection causes severe fever and thrombocytopenia syndrome with high mortality. It is extremely rare that the transmitting tick can be directly captured in the bitten wound and SFTSV can be isolated from both the captured tick and patient’s serum for establishing solid pathogen diagnosis. Case presentation We report a case infected with severe fever and thrombocytopenia bunyavirus. The 69-year-old male patient presented fever and tenderness on two lymph nodes in right groin. A visible tick bitten mark appeared on right upper quadrant of the patient’s abdomen and an alive tick was captured in the bitten wound upon physical examination. The virus was detected in both the captured tick that stayed in the bitten wound for seven days. The phylogenetic analysis indicated that the SFTSV isolated from the tick and the patient’s serum sample belonged to type B, in which the L/S segment of these two isolates shared 100% homology, while the M segment had 99.9% homology. the bitten patient was given various supportive cares and eventually died of multiple organ failure. Conclusions The present case provides direct evidence of SFTSV transmission from H. longicornis to humans and suggests that direct cross-species transmission can occur without additional intermediate hosts.

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