The shoulders of 'Homo antecessor' and modern humans are similar
The shoulders of 'Homo antecessor' and modern humans are similar
The shape of our shoulders was already present in the Lower Pleistocene, according to a pioneering study published today in the journal Scientific Reports, carried out by Daniel García Martínez and José María Bermúdez de Castro, paleoanthropologists at the Centro Nacional de Investigación sobre la Evolución Humana (CENIEH), in collaboration with David Green of Campbell University (USA).
Studying the shoulder (technically known as the "shoulder girdle") furnishes information on points significant for human evolution such as locomotion, body shape, the possibility of climbing with ease or the ability to launch objects like stones or spears with high accuracy.
The authors of this work were able to study for the first time shoulder growth and development in the species Homo antecessor, dated to 850,000 years old, using tools from virtual anthropology and 3D geometric morphometry. The results show that the course of development of the shoulder in this species was very similar to that in H. sapiens, although the growth might have been faster.
Almost one million years ago, our evolution had already attained almost all the biomechanical capacities characterizing the shoulder in modern humans, and it had definitively parted ways from the abilities still then retained by the more archaic species of the human phylogeny, including climbing with great agility.
To verify the changes undergone by this part of our anatomy, we need a flat bone: the shoulder blade or scapula. But, as the authors of this study state, “The fossil record of our phylogeny contains barely a handful of these highly delicate bones, which has posed enormous difficulties to studying the growth and development of the shoulders during human evolution”.
Two key fossils
By good luck, at level TD6 of the Gran Dolina site, situated in the Sierra de Atapuerca (Burgos), two scapulae have been conserved: one from a child and the other from an individual of age equivalent to a modern adolescent. These fossils were recovered during the excavation in the first decade of the twenty-first century and belonged to the species H. antecessor.
“In an earlier study of these two fossils, it had been noticed that the morphology of the scapulae was similar to our own. But until now, the growth and development model for the shoulders had remained unknown, and this work has now allowed us to check that our shoulder girdle bones have undergone modifications in accordance with different capacities”, says Bermúdez de Castro.
Comparative study
With the scant information available, it was known that the scapulae of Australopithecus species were similar in some ways to those of chimpanzees or gorillas but were different from our own. “We know that the development of our most archaic ancestors was very similar to that of the anthropoid apes, and the morphology of their shoulders shows that they still retained the capacity to climb with ease. We, on the contrary, have lost this ability”, explains García Martínez.
To determine when our anatomical peculiarities arose, in addition to virtual anthropology and 3D geometric morphometry, the researchers used complex statistical methods to study the development of the shoulder girdle in the species H. antecessor, comparing it with other species from the Pliocene and Lower Pleistocene, such as Australopithecus sediba and A. afarensis. A very broad sample from H. sapiens and chimpanzees (Pan troglodytes) was also used.
“This study shows that although there exist slight morphological differences between the scapulae of H. antecessor and H. sapiens, the former were much more similar to modern humans, to H. erectus and even to Australopithecus than to chimpanzees”, comments García Martínez.
With regard to how the scapulae grew, it was also seen that this was very different from what happens in chimpanzees, and comparable with H. sapiens. “However, it is true that the data seem to point to growth being more rapid in H. antecessor, as highlighted by the CENIEH research team on the basis of dental evidence”, emphasizes Bermúdez de Castro.
This paper lays the foundations for how the shoulder girdle developed in Lower Pleistocene species, and opens the door to new research studying shoulder development in fossil species, as it may become possible to expand the timeframe and study this development even in Pliocene species like the genus Australopithecus.
Full bibliographic information
Press release from CENIEH
The hatchet falls on... Writers & Lovers
The news of an upcoming Italian translation of "Writers & Lovers" by Lily King, brought back the memories of the terrible day and a half I spent reading this novel (and also a few reflections on the criteria on which Italian publishers chose what to translate and not to translate, but let's not well on that... for now).
My quite strongly negative opinion on this novel seems to clash with the many 5 star comments on web platforms (e.g.: Goodreads), therefore, for a while I thought I just hadn't understood the deep meaning that Lily King wanted to convey with her writing. Then, fortunately, in July, the Times Literary Supplement published a review that shared most of my negative thoughts (by Evelyn Toynton), and I finally felt understood.
Now, the following review will contain a number of spoilers: therefore, if you really really want to read "Writers & Lovers" you might want to stop here. If you want to save yourselves a rather pathetic experience, please feel free to carry on.
When I bought this book in early 2020 I should have known that a fancy title and a nice cover were going to be misleading...
The temporal lobes of Homo erectus were proportionally smaller than in H. sapiens
The temporal lobes of Homo erectus were proportionally smaller than in H. sapiens
Emiliano Bruner, a paleoneurologist at the Centro Nacional de Investigación sobre la Evolución Humana (CENIEH), has participated in a study published in the journal Quaternary International, on the anatomy of the temporal lobes in the brain of Homo erectus, which establishes that they were proportionally smaller than in modern humans.
In H. sapiens, the temporal lobes are relatively more highly developed than in other primates, although little is known about their anatomy in extinct human species, because they are housed in a very delicate region of the cranium known as the middle cranial fossa, which is often not conserved in fossil individuals.
An earlier study by the same team had shown that the size of the middle cranial fossa can be used to deduce the volume of the temporal lobes. In this new study, three anatomical diameters were analyzed in fossils of H. erectus and H. ergaster, and compared with the corresponding measurements for 51 modern humans. The results suggest that both fossil species had temporal lobes proportionally smaller than in humans today.
Moreover, “The Asiatic individuals, namely Homo erectus, had larger temporal lobes than in the African ones, Homo ergaster, although the scanty fossil record does not allow us to tell whether this is due to chance or a paleoneurological difference between the two species”, says Bruner.
As the temporal lobe is a brain region involved in the integration of many cognitive functions, such as memory, the emotions, hearing, social relations and language, any change in their sizes or proportions is of transcendent importance, as this could reveal variations in the development of their neurons or their connections, and therefore in the cognitive functions associated to this region of the cerebral cortex.
This study has been conducted by Alannah Pearson, a doctoral student of Emiliano Bruner at the Australian National University in Canberra (Australia), in collaboration with Professor David Polly, of Indiana University (USA).
Full bibliographic information
Press release from CENIEH
The Pulitzer Prize for Fiction 2020: when literature precedes history
The Pulitzer Prize for Fiction 2020: Great American Novels, Black Lives Matter, archetypes and stereotypes
The almost proverbial longtime obsession that American writers have always shown to have for writing the “Great American Novel” (an expression canonised by Philip Roth’s The Great American Novel) seems to have found its perfect embodiment in the finalist trio of this year’s Pulitzer Prize for Fiction.
Let’s be honest: not all past Pulitzer winners — let alone just finalists — have managed to contribute to the history of American literature, but this year, the year of Apocalypse apparently, our judges have provided us with a remarkable specimen of thriving American fictional prose.
The victory of The Nickel Boys, by Colson Whitehead (for the second time awarded with the prize, after his triumph in 2017 with The Underground Railroad) could not be more timely: only 21 days before the murder of George Floyd, which initiated the ongoing history-changing wave of protests of the Black Lives Matter movement, on May 4th 2020, a novel whose story revolves around white violence against black boys in an American reformatory, deservedly won the Pulitzer Prize. A prophecy? A foreshadow of things to come? Or perhaps just a signal, a symptom of the growing need for awareness on a social — and ultimately historical — issue that had been simmering just beneath the surface for way too long.
This is not simply an honest, profound, and well-timed novel on the condition of black people in the US. It is — I will be excused the redundancy from now on — a Great American Novel.
I quote from the Wikipedia page for GAN: “The term Great American Novel (GAN) refers to a canonical novel that is thought to capture the spirit of American life. It is generally regarded as being written by an American and dealing in some way with the question of America's national character. The Great American Novel is considered America's equivalent of the national epic.”
The Nickel Boys, though not canonically “epic” with its 215 pages, does indeed capture in a robust way the spirit of contemporary American life. Despite the fictional character of this novel, older and recent history has proved that the events narrated in Whitehead’s last book — the brutality of the violent and multiform abuse against (even young) black people — are facts that permeate everyday American (and not only) society and corrode its foundations. The question of black lives is, therefore, a question of America’s national character, and Whitehead’s powerful writing immortalises it in a way that few other writers (and I’m thinking of Toni Morrison above all) have been able to do so far: this is a profoundly personal, single, individual story that has the strength to turn itself into the archetype of a universal human condition of suffering, abuse, violence, and discrimination. Creating archetypes is indeed what good writing should normally bet able to do, whereas mediocre writing fills its pages with fragile and dull stereotypes. This is why, if one of the two winners of the Man Booker Prize 2019, Girl, Woman, Other, by Bernardine Evaristo, merely offers us a rather banal tracking shot of poorly written cliches (stereotypes, precisely!) on black women (and does not, therefore, portray a reality a reader can fully grasp), Whitehead, on the contrary, creates a fictional world that, in its uniqueness, makes the real world aware of its flaws, and resonates with archetypical strength. This is how it becomes epic too, and most resolutely deserves the title of Great American Novel.
What further enriches the literary scenario of this year’s Pulitzer Prize is the incontestable truth that the other two contenders also notably had all the characteristics of great American novels.
The Topeka School, by Ben Lerner, is a refined and sophisticated novel depicting a certain bourgeois cross-section of American society: the protagonists are a family of psychotherapists, whose young son is a champion of public debate. The narration is polyphonic not only thanks to the multitude of voices (mother, father, son), but also to the author’s choice of alternating the first and third-person speech. The narrative technique is wise, as the secretly hidden story of a boy called Darren — that touches tangentially yet significantly the lives of the protagonists — unwinds throughout the chapters without being ever explicitly told. This is potentially a great American novel, not only because it is beautifully written and masterfully orchestrated, but also because it tackles tactfully a number of hot themes of contemporary American society. Public speech and eloquence — persuasion and its danger —, above all, feminism, mental health and psychotherapy, but also and quite remarkably the critical role of education. This pastiche of themes could have easily risked creating yet another collection of stereotypical cliches, but Ben Lerner appears to know better than this, and chooses to give his novel a vigorous framework within which these problems interact naturally and vividly, and therefore can aim at universality.
Finally, we have The Dutch House, by Ann Patchett, perhaps the most traditional of the three novels: a family saga. The plot, somehow a modern and harsh rewriting of the fairytale of Cinderella, is that of two siblings (a brother and a sister, of whom the brother narrates the story), who are, on the one hand, the victims of the tragic destiny of their family (abandoned by their mother, kicked out from their family house by the second wife of their late father), and, on the other hand, the victims of their own violent obsession for the Dutch House. The house is the sumptuous place where they grew up — the materialisation of their father’s American dream, the dream of an ambitious and stubborn man, decided to substantiate his scaling of the social ladder through the possession of a dream house, the same house that will lead his wife to folly and escape.
The obsession of the two protagonists for the house will accompany them until old age and death, and will be inherited by future generations. If the plot is fundamentally simple, the feeling it conveys is undoubtedly epic: a blind, insistent, stubborn search for the evidence of the actuality of the past; a desperate chase of roots; a morbid yet rational attachment to the material possession — the house — which provided those roots; the physical and tangible component of memory.
By narrating these sentiments, universal yet so strongly connotated as typically American (isn’t in the big house, after all, the American dream?), Ann Patchett builds an epic novel, whose emotional strength is at times excruciating, whose simplicity describes folly, torment, resignation, family love, and a vast plethora of human emotions and actions. This is, in sum, a great (and in this case also traditional, though universal) American novel.
Ultimately, the Pulitzer Prize for Fiction 2020 amazes for its foresight and for the brilliance of choices, but most remarkably teaches how literature, at times, precedes history, how the big human and social questions often surface on the written page before action takes place. How great American novels (and hopefully great universal novels) can be a driving force to action and thought.
The Met Acquires Works by Pakistani Artist Lala Rukh
About the Artist
Press release from the Metropolitan Museum of Art.
Ancient DNA sheds light on Arctic hunter-gatherer migration to North America ~5,000 years ago
Ancient DNA sheds light on Arctic hunter-gatherer migration to North America ~5,000 years ago
An ancient population of Arctic hunter-gatherers, known as Paleo-Eskimos, made a significant genetic contribution to populations living in Arctic North America today
New research reveals the profound impact of Arctic hunter-gathers who moved from Siberia to North America about 5000 years ago on present-day Native Americans. Although this group is well-known from archaeology and ancient DNA, previous genetic studies suggested that they may have been largely replaced by the groups that gave rise to present-day Arctic peoples such as the Inuit, Yup’ik, and Aleuts. The present study proves that many present-day North Americans derive significant heritage from this ancient population.
The first humans in North America arrived from Asia some time before 14,500 years ago. The next major stream of gene flow came about 5000 years ago, and is known to archaeologists as Paleo-Eskimos. About 800 years ago, the ancestors of the present-day Inuit and Yup'ik people replaced this population across the Arctic. By about 700 years ago, the archaeological evidence for the Paleo-Eskimo culture disappeared. Their genetic legacy in living populations has been contentious, with several genetic studies arguing that they made little contribution to later North Americans.
In the current study, researchers generated genome-wide data from 48 ancient individuals and 93 modern individuals from Siberia, Alaska, the Aleutian Islands and Canada, and compared this with previously published data. The researchers used novel analysis methods to create a comprehensive model of population history that included many ancient and modern groups to determine how they might be related to each other. "Our study is unique, not only in that it greatly expands the number of ancient genomes from this region, but because it is the first study to comprehensively describe all of these populations in one single coherent model," states Stephan Schiffels of the Max Planck Institute for the Science of Human History.
Paleo-Eskimos left a lasting legacy that extends across North America
The researchers were able to show that a substantial proportion of the genetic heritage of all ancient and modern American Arctic and Chukotkan populations comes from Paleo-Eskimos. This includes people speaking Eskimo-Aleut languages, such as the Yup'ik, Inuit and Aleuts, and groups speaking Na-Dene languages, such as Athabaskan and Tlingit speakers, in Canada, Alaska, and the lower 48 states of the United States.
Based on the researchers' analysis, Paleo-Eskimos interbred with people with ancestry similar to more southern Native peoples shortly after their arrival to Alaska, between 5,000 and 4,000 years ago. The ancestors of Aleutian Islanders and Athabaskans derive their genetic heritage directly from the ancient mixture between these two groups. The researchers also found that the ancestors of the Inuit and Yup'ik people crossed the Bering Strait at least three times: first as Paleo-Eskimos to Alaska, second as predecessors of the Old Bering Sea archaeological culture back to Chukotka, and third to Alaska again as bearers of the Thule culture. During their stay in Chukotka that likely lasted for more than 1000 years, Yupik and Inuit ancestors also admixed with local groups related to present-day Chukchi and local peoples from Kamchatka.
Paleo-Eskimo ancestry is particularly widespread today in Na-Dene language speakers, which includes Athabaskan and Tlingit communities from Alaska and northern Canada, the West Coast of the United States, and the southwest United States.
"For the last seven years, there has been a debate about whether Paleo-Eskimos contributed genetically to people living in North America today; our study resolves this debate and furthermore supports the theory that Paleo-Eskimos spread Na-Dene languages," explains David Reich of Harvard Medical School and the Howard Hughes Medical Institute. "One of the most striking case examples from our study is the ancient DNA we generated from the ancient Athabaskan site of Tochak McGrath in interior Alaska, where we worked in consultation with the local community to obtain data from three approximately seven hundred year old individuals. We found that these individuals, who lived after the time when the Paleo-Eskimo archaeological culture disappeared across North America, are well modeled as a mixture of the same two ancestry components as those found in Athabaskans today, and derived more than 40% of their ancestry from Paleo-Eskimos.
A case example for how genetics can be combined with archaeology to shed new light on the past
The researchers hope that the paper will provide an example of the value of genetic data, in the context of archaeological knowledge, to resolve long-standing questions.
"Determining what happened to this population was not possible from the archaeological record alone," explains Pavel Flegontov of the University of Ostrava. "By analyzing genetic data in concert with the archaeological data, we can meaningfully improve our understanding of the prehistory of peoples of this region. We faced challenging analytical problems due to the complex sequence of gene flows that have shaped ancestries of peoples on both sides of the Bering Strait. Reconstructing this sequence of events required new modelling approaches that we hope may be useful for solving similar problems in other regions of the world."
Press release from the Max Planck Institute for the Science of Human History / Max-Planck-Instituts für Menschheitsgeschichte
Suskityrannus hazelae: a new 3-foot-tall relative of Tyrannosaurus rex
New 3-foot-tall relative of Tyrannosaurus rex
A new relative of the Tyrannosaurus rex - much smaller than the huge, ferocious dinosaur made famous in countless books and films, including, yes, "Jurassic Park" - has been discovered and named by a Virginia Tech paleontologist and an international team of scientists.
The newly named tyrannosauroid dinosaur - Suskityrannus hazelae - stood rougly 3 feet tall at the hip and was about 9 feet in length, the entire animal only marginally longer than the just the skull of a fully grown Tyrannosaurus rex, according to Sterling Nesbitt, an assistant professor with Department of Geosciences in the Virginia Tech College of Science. In a wild twist to this discovery, Nesbitt found the fossil at age 16 whilst a high school student participating in a dig expedition in New Mexico in 1998, led by Doug Wolfe, an author on the paper.
In all, Suskityrannus hazelae is believed to have weighed between 45 and 90 pounds. The typical weight for a full-grown Tyrannosaurus rex is roughly 9 tons. Its diet likely consisted of the same as its larger meat-eating counterpart, with Suskityrannus hazelae likely hunting small animals, although what it hunted is unknown. The dinosaur was at least 3 years old at death based on an analysis of its growth from its bones.
The fossil dates back 92 million years to the Cretaceous Period, a time when some of the largest dinosaurs ever found lived.
"Suskityrannus gives us a glimpse into the evolution of tyrannosaurs just before they take over the planet," Nesbitt said. "It also belongs to a dinosaurian fauna that just proceeds the iconic dinosaurian faunas in the latest Cretaceous that include some of the most famous dinosaurs, such as the Triceratops, predators like Tyrannosaurus rex, and duckbill dinosaurs like Edmontosaurus."
The findings are published in the latest online issue of Nature Ecology & Evolution. In describing the new find, Nesbitt said, "Suskityrannus has a much more slender skull and foot than its later and larger cousins, the Tyrannosaurus rex. The find also links the older and smaller tyrannosauroids from North America and China with the much larger tyrannosaurids that lasted until the final extinction of non-avian dinosaurs.
(Tyrannosaurus rex small arm jokes abund. So, if you're wondering how small the arms of Suskityrannus were, Nesbitt and his team are not exactly sure. No arm fossils of either specimen were found, but partial hand claws were found. And, they are quite small. Also not known: If Suskityrannus had two or three fingers.)
Two partial skeletons were found. The first included a partial skull that was found in 1997 by Robert Denton, now a senior geologist with Terracon Consultants, and others in the Zuni Basin of western New Mexico during an expedition organized by Zuni Paleontological Project leader Doug Wolfe.
The second, more complete specimen was found in 1998 by Nesbitt, then a high school junior with a burgeoning interest in paleontology, and Wolfe, with assistance in collection by James Kirkland, now of the Utah Geological Survey. "Following Sterling out to see his dinosaur, I was amazed at how complete a skeleton was lying exposed at the site," Kirkland said.
For much of the 20 years since the fossils were uncovered, the science team did not know what they had.
"Essentially, we didn't know we had a cousin of Tyrannosaurus rex for many years," Nesbitt said. He added the team first thought they had the remains of a dromaeosaur, such as Velociraptor. During the late 1990s, close relatives Tyrannosaurus rex simply were not known or not recognized. Since then, more distant cousins of Tyrannosaurus rex, such as Dilong paradoxus, have been found across Asia.
The fossil remains were found near other dinosaurs, along with the remains of fish, turtles, mammals, lizards, and crocodylians. From 1998 until 2006, the fossils remain stored at the Arizona Museum of Natural History in Mesa, Arizona. After 2006, Nesbitt brought the fossils with him through various postings as student and researcher in New York, Texas, Illinois, and now Blacksburg. He credits the find, and his interactions with the team members on the expedition, as the start of his career.
"My discovery of a partial skeleton of Suskityrannus put me onto a scientific journy that has framed my career," said Nesbitt, also a member of the Virginia Tech Global Change Center. "I am now an assistant professor that gets to teach about Earth history."
The name Suskityrannus hazelae is derived from "Suski," the Zuni Native American tribe word for "coyote," and from the Latin word 'tyrannus' meaning king and 'hazelae' for Hazel Wolfe, whose support made possible many successful fossil expeditions in the Zuni Basin. Nesbitt said permission was granted from the Zuni Tribal Council to use the word "Suski."
Funding for Nesbitt and his team’s research into Suskityrannus came from the Discovery Channel, the Virginia Tech Department of Geosciences, and the American Museum of Natural History. Additional scientists on the team come from the University of Edinburgh, the Natural History Museum of Los Angeles, the University of Utah, and several more institutions.
Press release from Virginia Tech
The dead may outnumber the living on Facebook within 50 years
The dead may outnumber the living on Facebook within 50 years
New analysis by academics from the Oxford Internet Institute (OII), part of the University of Oxford, predicts the dead may outnumber the living on Facebook within fifty years, a trend that will have grave implications for how we treat our digital heritage in the future.
The analysis predicts that, based on 2018 user levels, at least 1.4 billion members will die before 2100. In this scenario, the dead could outnumber the living by 2070. If the world's largest social network continues to expand at current rates, however, the number of deceased users could reach as high as 4.9 billion before the end of the century.
"These statistics give rise to new and difficult questions around who has the right to all this data, how should it be managed in the best interests of the families and friends of the deceased and its use by future historians to understand the past," said lead author Carl Öhman, a doctoral candidate at the OII.
"On a societal level, we have just begun asking these questions and we have a long way to go. The management of our digital remains will eventually affect everyone who uses social media, since all of us will one day pass away and leave our data behind. But the totality of the deceased user profiles also amounts to something larger than the sum of its parts. It is, or will at least become, part of our global digital heritage."
Co-author David Watson, also a DPhil student at the OII, explained: "Never before in history has such a vast archive of human behaviour and culture been assembled in one place. Controlling this archive will, in a sense, be to control our history. It is therefore important that we ensure that access to these historical data is not limited to a single for-profit firm. It is also important to make sure that future generations can use our digital heritage to understand their history."
The analysis sets up two potential extreme scenarios, arguing that the future trend will fall somewhere in between:
- The first scenario assumes that no new users join as of 2018. Under these conditions, Asia's share of dead users increases rapidly to account for nearly 44% of the total by the end of the century. Nearly half of those profiles come from India and Indonesia, which together account for just under 279 million Facebook mortalities by 2100.
- The second scenario assumes that Facebook continues to grow by its current rate of 13% globally, every year, until each market reaches saturation. Under these conditions, Africa will make up a growing share of dead users. Nigeria, in particular, becomes a major hub in this scenario, accounting for over 6% of the total. By contrast, Western users will account for only a minority of users, with only the US making the top 10.
"The results should be interpreted not as a prediction of the future, but as a commentary on the current development, and an opportunity to shape what future we are headed towards," explains Öhman. "But this has no bearing on our larger point that critical discussion of online death and its macroscopic implications is urgently needed. Facebook is merely an example of what awaits any platform with similar connectivity and global reach."
Watson added: "Facebook should invite historians, archivists, archaeologists and ethicists to participate in the process of curating the vast volume of accumulated data that we leave behind as we pass away. This is not just about finding solutions that will be sustainable for the next couple of years, but possibly for many decades ahead."
The predictions are based on data from the United Nations, which provide the expected number of mortalities and total populations for every country in the world distributed by age, and Facebook data scraped from the company's Audience Insights feature. While the study notes that this self-reported dataset has several limitations, this provides the most comprehensive publicly available estimate of the network's size and distribution
Press release from the University of Oxford
The research article "Are the dead taking over Facebook? A Big Data approach to the future of death online", by Carl J. Öhman and David Watson, has been published on Big Data & Society (April 23, 2019).
Meet Callichimaera perplexa, the platypus of crabs
Meet Callichimaera perplexa, the platypus of crabs
New Haven, Conn. - The crab family just got a bunch of new cousins -- including a 95-million-year-old chimera species that will force scientists to rethink the definition of a crab.
An international team of researchers led by Yale paleontologist Javier Luque announced the discovery of hundreds of exceptionally well-preserved specimens from Colombia and the United States that date back to the mid-Cretaceous period of 90-95 million years ago. The cache includes hundreds of tiny comma shrimp fossils, several true shrimp, and an entirely new branch of the evolutionary tree for crabs.
The most intriguing discovery, according to the researchers, is Callichimaera perplexa, the earliest example of a swimming arthropod with paddle-like legs since the extinction of sea scorpions more than 250 million years ago. The name derives from a chimera, a mythological creature that has body features from more than one animal. Callichimaera's full name translates into "perplexing beautiful chimera."
Luque noted that Callichimaera's "unusual and cute" appearance, including its small size -- about the size of a quarter -- large compound eyes with no sockets, bent claws, leg-like mouth parts, exposed tail, and long body are features typical of pelagic crab larvae. This suggests that several of the larval traits seen in this "perplexing chimera" might have been retained and amplified in miniaturized adults via changes in the timing and rates of development. This is a process called "heterochrony," which may lead to the evolution of novel body plans.
"Callichimaera perplexa is so unique and strange that it can be considered the platypus of the crab world," said Luque. "It hints at how novel forms evolve and become so disparate through time. Usually we think of crabs as big animals with broad carapaces, strong claws, small eyes in long eyestalks, and a small tail tucked under the body. Well, Callichimaera defies all of these 'crabby' features and forces a re-think of our definition of what makes a crab a crab."
A study about the discovery appears in the April 24 online edition of the journal Science Advances.
"It is very exciting that today we keep finding completely new branches in the tree of life from a distant past, especially from regions like the tropics, which despite being hotspots of diversity today, are places we know the least about in terms of their past diversity," Luque said.
###
Luque's team included researchers from the University of Alberta, Kent State University, the University of Montreal, the Smithsonian Tropical Research Institute in Panama, the Canadian Parks and Wilderness Society, the National Autonomous University of Mexico, the University of Nevada, and the College of Communication and Design in Boca Raton, Fla.
Press release from Yale University
Ancient 'Texas Serengeti' had elephant-like animals, rhinos, alligators and more
Ancient 'Texas Serengeti' had elephant-like animals, rhinos, alligators and more
During the Great Depression, some unemployed Texans were put to work as fossil hunters. The workers retrieved tens of thousands of specimens that have been studied in small bits and pieces while stored in the state collections of The University of Texas at Austin for the past 80 years.
Now, decades after they were first collected, a UT researcher has studied and identified an extensive collection of fossils from dig sites near Beeville, Texas, and found that the fauna make up a veritable "Texas Serengeti" - with specimens including elephant-like animals, rhinos, alligators, antelopes, camels, 12 types of horses and several species of carnivores. In total, the fossil trove contains nearly 4,000 specimens representing 50 animal species, all of which roamed the Texas Gulf Coast 11 million to 12 million years ago.
A paper describing these fossils, their collection history and geologic setting was published April 11 in the journal Palaeontologia Electronica.
"It's the most representative collection of life from this time period of Earth history along the Texas Coastal Plain," said Steven May, the research associate at the UT Jackson School of Geosciences who studied the fossils and authored the paper.
In addition to shedding light on the inhabitants of an ancient Texas ecosystem, the collection is also valuable because of its fossil firsts. They include a new genus of gomphothere, an extinct relative of elephants with a shovel-like lower jaw, and the oldest fossils of the American alligator and an extinct relative of modern dogs.
The fossils came into the university's collection as part of the State-Wide Paleontologic-Mineralogic Survey that was funded by the Works Progress Administration (WPA), a federal agency that provided work to millions of Americans during the Great Depression. From 1939 to 1941, the agency partnered with the UT Bureau of Economic Geology, which supervised the work and organized field units for collecting fossils and minerals across the state.
Despite lasting only three years, the survey found and excavated thousands of fossils from across Texas including four dig sites in Bee and Live Oak counties, with the majority of their finds housed in what is now the Texas Vertebrate Paleontology Collections at the Jackson School Museum of Earth History. Over the years, a number of scientific papers have been published on select groups of WPA specimens. But May's paper is the first to study the entire fauna.
This extensive collection of fossils is helping to fill in gaps about the state's ancient environment, said Matthew Brown, the director of the museum's vertebrate paleontology collections.
The emphasis on big mammals is due in large part to the collection practices of the fossil hunters, most of whom were not formally trained in paleontology. Large tusks, teeth and skulls were easier to spot - and more exciting to find - than bones left by small species.
"They collected the big, obvious stuff," May said. "But that doesn't fully represent the incredible diversity of the Miocene environment along the Texas Coastal Plain."
In order to account for gaps in the collection, May tracked down the original dig sites so he could screen for tiny fossils such as rodent teeth. One of the sites was on a ranch near Beeville owned by John Blackburn. Using aerial photography and notes from the WPA program stored in the university's archives, May and the research team were able to track down the exact spot of an original dig site.
"We're thrilled to be a part of something that was started in 1939," Blackburn said. "It's been a privilege to work with UT and the team involved, and we hope that the project can help bring additional research opportunities."
Scores of WPA-era fossils in the UT collections are still secured in plaster field jackets, waiting to be unpacked for future research projects. Lab managers Deborah Wagner and Kenneth Bader are supervising their preparation, which includes teaching UT students fossil prep skills so they can pick up where the WPA workers left off.
Wagner said that the advantage of unpacking fossils decades later is that they are able to apply modern research techniques that scientists from past eras wouldn't have dreamed possible.
"We are able to preserve more detailed anatomy and answer questions that require higher resolution data," she said.
May said that he plans to continue to study the fossils as more are prepared.
Press release from the University of Texas at Austin
