PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

Two Jurassic mammaliaforms from China shed light on mammalian evolution

Two Jurassic mammaliaforms from China shed light on mammalian evolution
2024-04-03
(Press-News.org) Mammaliaforms are extinct and extant organisms that are closely related to mammals. Studying mammaliaforms helps scientists understand the evolutionary processes that led to various mammalian features.

In two consecutive studies in Nature, Dr. MAO Fangyuan and Dr. ZHANG Chi from the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) of the Chinese Academy of Sciences, together with colleagues from Australia and the United States, recently reported two Jurassic mammaliaforms from China, revealing the earliest dental diversification, mandibular middle ears, and articular-quadrate joint transformation of mammaliaforms.

The studies provide key information about the evolutionary shift from reptilian jaw bones to early mammalian middle ear ossicles, presenting new perspectives on the early diversity of mammaliaforms and reshaping the early mammalian phylogeny.

Shuotheriids were Jurassic mammaliaforms with pseudotribosphenic molars that featured a "pseudotalonid" (a basin-like structure) in front of the trigonid in the lower molars. In contrast, molars in living mammals feature a tribosphenic pattern where the talonid is located behind the trigonid and "receives," i.e., interlocks with, the protocone of the upper molar for food processing/mastication.

Traditionally, shuotheriids have been phylogenetically grouped with "australosphenidans" (including the living monotremes), but this relationship is controversial and leaves some puzzling morphological, paleogeographical, and functional issues unexplained in mammalian forms.

In the first paper, the researchers examined two specimens from the Middle Jurassic Daohugou locality in Inner Mongolia and established a new genus and species of shuotheriid, Feredocodon chowi.

Based on the evidence of the complete dentitions, occlusal relationships, and the serial homology of the teeth, the researchers proposed a new interpretation: The pseudotribosphenic molars are actually homologous to the molar pattern of docodontans.

The results of phylogenetic analyses reconstructed from the revised dental characters suggest that a Morganucodon-like ancestor independently gave rise to three major groups of mammaliaforms: Docodontiformes (Docodonta and Shuotheridia), Allotheria, and Holotheria (symmetrodontans, therians, and kin). The key feature of the tooth evolution in early mammaliaforms is that the molars, which arose from the ancestral triconodont pattern as in Morganucodon, became broader and more complex to accommodate more efficient food processing. However, the evolutionary processes of the three groups took place in different directions.

In the second paper, the researchers reported the mandibular middle ears (MdME) of two species—one being the shuotheriid Feredocodon described above and the other being a Morganucodon-like animal from the Early Jurassic Lufeng Biota, named Dianoconodon youngi.

The two species showed some new morphological features that support the evolutionary shift from jaw joint bones to middle ear ossicles in early mammals. The mandibular features suggest that one of the dual jaw joints in the ancestral Morganucodon, the articular-quadrate joint, lost its load-bearing function in Dianoconodon, while the mandibular middle ear was better adapted for hearing. The postdentary bones of the shuotheriid species are more advanced, showing characteristics suitable for a purely auditory function.

The new evidence provides insight into how the ossified Meckel's cartilage functioned as a stabilizing mechanism and reveals that the medial displacement of the quadrate relative to the articular bone played a critical role in the transformation from a load-bearing jaw joint to the middle ear structures.

This research strongly supports and enhances the view that the gradual evolution of the mammalian middle ear is a classic example of vertebrate evolution.

Feredocodon chowi and Dianoconodon youngi are named in honor of Professors Minchen CHOW (ZHOU Minchen) and Chung-Chien YOUNG (YANG Zhongjian), respectively. These studies were supported by the National Natural Science Foundation of China and the Youth Innovation Promotion Association of CAS.

END

[Attachments] See images for this press release:
Two Jurassic mammaliaforms from China shed light on mammalian evolution Two Jurassic mammaliaforms from China shed light on mammalian evolution 2 Two Jurassic mammaliaforms from China shed light on mammalian evolution 3

ELSE PRESS RELEASES FROM THIS DATE:

Socioecologic factors and racial differences in breast cancer prognostic scores

2024-04-03
About The Study: The findings of this study suggest that the consequences of structural racism extend beyond inequities in health care to drive disparities in breast cancer outcome. Additional research is needed with more comprehensive social and environmental measures to better understand the influence of social determinants on aggressive estrogen receptor-positive tumor biology among racial and ethnic minoritized women from disadvantaged and historically marginalized communities.  Authors: Gregory S. Calip, Pharm.D., M.P.H., Ph.D., of the University of Southern California in Los Angeles, is the corresponding author.  To access the embargoed study: ...

Disparities in mentorship and implications for surgical resident education and wellness

2024-04-03
About The Study: In a survey study of residents of all accredited general surgery programs, one-third of trainees reported lack of meaningful mentorship, particularly non-white or Hispanic trainees. Although education and wellness are multifactorial issues, mentorship was associated with improvement; thus, efforts to facilitate mentorship are needed, especially for minoritized residents.  Authors: Yue-Yung Hu, M.D., M.P.H., of Northwestern University in Chicago, is the corresponding author. To access the embargoed study: Visit our For The Media website at this link ...

Intelligent liquid

Intelligent liquid
2024-04-03
Researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have developed a programmable metafluid with tunable springiness, optical properties, viscosity and even the ability to transition between a Newtonian and non-Newtonian fluid.  The first-of-its-kind metafluid uses a suspension of small, elastomer spheres — between 50 to 500 microns — that buckle under pressure, radically changing the characteristics of the fluid. The metafluid could be used in everything ...

New Sylvester study targets major risk factor for gastric cancer

New Sylvester study targets major risk factor for gastric cancer
2024-04-03
MIAMI, FLORIDA (April 3, 2024) – What if we could eliminate a major risk factor for stomach cancer in Black, Asian, Latino and other vulnerable populations? A new study from Sylvester Comprehensive Cancer Center at the University of Miami Miller School of Medicine shows the feasibility of reaching out to high-risk communities with free, accessible testing and treatment for Helicobacter pylori bacterium infection – a major risk factor for gastric cancer. Shria Kumar, M.D., a physician-scientist at Sylvester, sees patients with gastric cancer in her ...

New Jurassic fossil findings provide insights into the development of the middle ear in mammals

2024-04-03
New Jurassic fossil findings provide insights into the development of the middle ear in mammals An international team of palaeontologists has made a significant discovery in fossils that offer key information about the evolutionary shift from the jaw joint bones to those of the middle ear in early mammals. The findings published today in the prestigious journal Nature provide a clearer insight into the evolution of hearing in mammaliaforms. The fossils, from the Jurassic Period, are of two different ...

JAMA paper: In people with opioid use disorder, telemedicine treatment for HCV was more than twice as successful as off-site referral

JAMA paper: In people with opioid use disorder, telemedicine treatment for HCV was more than twice as successful as off-site referral
2024-04-03
BUFFALO, N.Y. – People with opioid use disorder who have hepatitis C virus (HCV) were twice as likely to be successfully treated and cured from HCV if they received facilitated telemedicine treatment at their opioid treatment program (OTPs) than if they were referred off-site to another provider. Those are the findings published today by a University at Buffalo team of researchers in the Journal of the American Medical Association (JAMA). The study is one of only a few randomized controlled ...

Genetic analysis reveals true origin of chronic kidney disease in undiagnosed patients

Genetic analysis reveals true origin of chronic kidney disease in undiagnosed patients
2024-04-03
Tokyo Medical and Dental University (TMDU) researchers discover that known genetic variants might account for a large portion of chronic kidney diseases of unclear origin Tokyo, Japan – Chronic kidney disease (CKD) is extremely prevalent among adults, affecting over 800 million individuals worldwide. Many of these patients eventually require therapy to supplement or replace kidney functions, such as dialysis or kidney transplant. While most CKD cases originate from lifestyle-related factors or diseases such as diabetes and hypertension, the underlying ...

Jurassic shuotheriids reveal earliest dental diversification of mammaliaforms

2024-04-03
Palaeontologists have presented a new insight into the initial dental variations across mammaliaforms, providing a fresh perspective on the evolutionary past of these ancient beasts. The discovery, involving a team of international researchers including Professor Patricia Vickers-Rich from the Monash University School of Earth, Atmosphere and Environment, is published today in the renowned journal Nature. The research, conducted by a group of palaeontologists from prestigious institutions in New York, China and Australia, examines the tooth structure of the Jurassic ...

Novel high entropy alloy nanoparticle catalysts for growing high-density carbon nanotubes

Novel high entropy alloy nanoparticle catalysts for growing high-density carbon nanotubes
2024-04-03
High entropy alloys (HEAs) have attracted significant attention in various fields due to their unique properties such as high strength and hardness, and high thermal and chemical stabilities. Unlike conventional alloys, which typically incorporate small quantities of one or two additional metals, HEAs constitute a solid solution of five or more metals in equal atomic ratio. This unique composition results in unique and complex surface structures that contain many different active sites suitable for catalytic reactions. As a result, in recent years, HEA nanoparticles (NPs) have been extensively studied for their catalytic potential.   However, despite their ...

COVID-19 vaccination as effective for adults with common mental disorders as for those without

2024-04-03
INDIANAPOLIS – A large multi-state electronic health record-based study from the Centers for Disease Control and Prevention’s (CDC’s) VISION Network has found that COVID-19 vaccines are as effective for adults with anxiety or depression or mood disorders as for individuals without these common diagnoses. This is one of the first studies to evaluate COVID-19 mRNA vaccine effectiveness for those living with mental illness. While vaccination provided similar protection regardless of psychiatric diagnosis (none, one or multiple ...

LAST 30 PRESS RELEASES:

Scientists discover a secret to regulating our body clock, offering new approach to end jet lag

Impact of pollutants on pollinators, and how neural circuits adapt to temperature changes

Researchers seek to improve advanced pain management using AI for drug discovery

‘Neutron Nexus’ brings universities, ORNL together to advance science

Early release from NEJM Evidence

UMass Amherst astronomer leads science team helping to develop billion-dollar NASA satellite mission concept

Cultivating global engagement in bioengineering education to train students skills in biomedical device design and innovation

Life on Earth was more diverse than classical theory suggests 800 million years ago, a Brazilian study shows

International clean energy initiative launches global biomass resource assessment

How much do avoidable deaths impact the economy?

Federal government may be paying twice for care of veterans enrolled in Medicare Advantage plans

New therapeutic target for cardiac arrhythmias emerges

UC Irvine researchers are first to reveal role of ophthalmic acid in motor function control

Moffitt study unveils the role of gamma-delta T cells in cancer immunology

Drier winter habitat impacts songbirds’ ability to survive migration

Donors enable 445 TPDA awards to Neuroscience 2024

Gut bacteria engineered to act as tumor GPS for immunotherapies

Are auditory magic tricks possible for a blind audience?

Research points to potential new treatment for aggressive prostate cancer subtype

Studies examine growing US mental health safety net

Social risk factor domains and preventive care services in US adults

Online medication abortion direct-to-patient fulfillment before and after the Dobbs v Jackson decision

Black, Hispanic, and American Indian adolescents likelier than white adolescents to be tested for drugs, alcohol at pediatric trauma centers

Pterosaurs needed feet on the ground to become giants

Scientists uncover auditory “sixth sense” in geckos

Almost half of persons who inject drugs (PWID) with endocarditis will die within five years; women are disproportionately affected

Experimental blood test improves early detection of pancreatic cancer

Groundbreaking wastewater treatment research led by Oxford Brookes targets global challenge of toxic ‘forever chemicals’

Jefferson Health awarded $2.4 million in PCORI funding

Cilta-cel found highly effective in first real-world study

[Press-News.org] Two Jurassic mammaliaforms from China shed light on mammalian evolution