Christopher Brochu

Christopher Brochu
University of Iowa | UI · earth and environmental sciences

PhD

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127
Publications
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Introduction

Publications

Publications (127)
Article
We describe two new osteolaemine crocodylids from the Early and early Middle Miocene of Kenya: Kinyang mabokoensis tax. nov. (Maboko, 15 Ma) and Kinyang tchernovi tax. nov. (Karungu and Loperot, 18 Ma). Additional material referable to Kinyang is known from Chianda and Moruorot. The skull was broad and dorsoventrally deep, and the genus can be diag...
Article
Crocodylians today live in tropical to subtropical environments, occupying mostly shallow waters. Their body size changes drastically during ontogeny, as do their skull dimensions and bite forces, which are associated with changes in prey preferences. Endocranial neurosensory structures have also shown to change ontogenetically, but less is known a...
Conference Paper
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In this study, we describe a new crocodile skull from the world-renowned palaeontological and archaeological site of Olduvai Gorge (Tanzania). The fossil, discovered and collected in 2016 during an annular solar eclipse and therefore nicknamed “Black Sun,” was found in a new trench excavated by the THOR (Tanzania Human Origins Research) team at sit...
Article
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Olduvai Gorge (northern Tanzania) is one of the best known and most iconic palaeontological and archaeological sites in the world. in more than a century of research it has yielded an impressive record of fossils and stone tools which stands as a compendium of human evolution in the context of environmental changes of east Africa in the last 2 Ma....
Article
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The discovery of cryptic biodiversity has blossomed under the advancements of genetic techniques, but species identification via morphology remains crucial to effective conservation efforts. In this study, we tested the use of continuous cranial shape variation in distinguishing the two living species of Mecistops: the West African slender‐snouted...
Article
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Ancient DNA is transforming our ability to reconstruct historical patterns and mechanisms shaping modern diversity and distributions. In particular, molecular data from extinct Holocene island faunas have revealed surprising biogeographic scenarios. Here, we recovered partial mitochondrial (mt) genomes for 1300–1400 year old specimens (n = 2) of th...
Article
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Brochuchus is a small crocodylid originally based on specimens from the early Miocene of Rusinga Island, Lake Victoria, Kenya. Here, we report occurrences of Brochuchus from several early and middle Miocene sites. Some are from the Lake Victoria region, and others are in the Lake Turkana Basin. Specimens from the middle Miocene Maboko locality form...
Article
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Deinosuchus is a lineage of giant (≥10 m) Late Cretaceous crocodylians from North America. These were the largest semiaquatic predators in their environments and are known to have fed on large vertebrates, including contemporaneous terrestrial vertebrates such as dinosaurs. Fossils have been found in units of Campanian age from northern Mexico to M...
Article
Allodaposuchus precedens is a basal member of Eusuchia, which was established almost a century ago on a set of cranial and postcranial fragmentary remains from the lower Maastrichtian of Vălioara, Romania. It was the first described member and type species of Allodaposuchidae, a recently described European clade representing one of the nearest outg...
Article
Major evolutionary transitions, in which animals develop new body plans and adapt to dramatically new habitats and lifestyles, have punctuated the history of life. The origin of cetaceans from land-living mammals is among the most famous of these events. Much earlier, during the Mesozoic Era, many reptile groups also moved from land to water, but t...
Article
Allodaposuchus precedens is a basal member of Eusuchia, which was established almost a century ago on a set of cranial and postcranial fragmentary remains from the lower Maastrichtian of Vălioara, Romania. It was the first described member and type species of Allodaposuchidae, a recently described European clade representing one of the nearest outg...
Article
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Mourasuchus is one of the most peculiar crocodylians of all time, showing an unusual ‘duck-faced’ rostrum with thin, gracile mandibles. It includes four species restricted to the South American Miocene. Here, we describe ten late Miocene specimens of Mourasuchus, nine from the Solim~oes Formation of Brazil and one from Bolivia. All specimens are as...
Article
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Extant crocodylomorphs are semiaquatic ambush predators largely restricted to freshwater or estuarine environments, but the group is ancestrally terrestrial and inhabited a variety of ecosystems in the past. Despite its rich ecological history, little effort has focused on elucidating the historical pattern of ecological transitions in the group. T...
Article
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Cranial and postcranial elements attributed to the alligatoroid Bottosaurus harlani Meyer, 1832 Meyer, H. von. 1832. Paleologica zur Geshichte der Erde und irher Geschöpfe. S. Schmerber, Frankurt-am-Main, 560 pp. [Google Scholar], are described from the Rowan Fossil Quarry, a Cretaceous–Paleogene locality in Mantua Township, New Jersey, U.S.A. This...
Chapter
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The full text for this book chapter is not available as a pdf. You can see a sample that is mostly the table of contents here: https://www.researchgate.net/publication/330675876_Messel_An_Ancient_Greenhouse_Ecosystem/ The full book is here: https://www.schweizerbart.de/publications/detail/isbn/9783510614110
Preprint
Actualistic observations form the basis of many taphonomic studies in paleontology. However, surveys limited by environment or taxon may not be applicable far beyond the bounds of the initial observations. Even when multiple studies exploring the potential variety within a taphonomic process exist, quantitative methods for comparing these datasets...
Article
Three crocodylid species are known from the Pliocene Kanapoi locality in the western Turkana Basin. One of these, Crocodylus thorbjarnarsoni, includes material previously referred to Crocodylus niloticus (the modern Nile crocodile currently living in Lake Turkana) and Rimasuchus lloydi. C. thorbjarnarsoni was a gigantic horned crocodile similar in...
Preprint
Crocodylians are known to consume and modify bones, but actualistic observations of their bite marks have been limited to forensic case studies and surveys of two taxa: Crocodylus niloticus and Crocodylus porosus. To further explore patterns of crocodylian bite mark expression, we performed a survey of traces left by Alligator mississippiensis. We...
Article
Abstract. The purpose of this application, under Article 75.5 of the Code, is to set aside all type fixations for the crocodyliform Allodaposuchus precedens Nopcsa, 1928, and to designate a neotype. The type series of A. precedens includes specimens from the Maastrichtian (Late Cretaceous) of Vălioara, housed at the Magyar Állami Földtani Intézet...
Article
Purpose During the last two decades, several specimens of eusuchian crocodyliforms have been described from the Campanian and Maastrichtian (Late Cretaceous) record of Europe. Most of them are now included in the recently described clade Allodaposuchidae. This clade is recognized as the sister group of the crown Crocodylia. The type species of Allo...
Article
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Although frequent in vertebrates (e.g. crocodylians, stem-tetrapods, turtles), the adaptive significance of bone ornamentation, that is the honeycomb-like pattern of pits and ridges that occur on the surface of dermal bones, remains poorly understood. In order to help assess the evolutionary history and ecological correlates of this character, orna...
Article
The genus Allodaposuchus is an endemic eusuchian from the Late Cretaceous of Europe. This genus was erected in 1928 by Baron Franz Nopcsa based on Allodaposuchus precedens from the Maastrichtian of Romania. Fragmentary skulls recovered from France and Spain were later referred to A. precedens, but three new species of Allodaposuchus have since been...
Article
Actualistic observations form the basis of many taphonomic studies in paleontology. However, surveys limited by environment or taxon may not be applicable far beyond the bounds of the initial observations. Even when multiple studies exploring the potential variety within a taphonomic process exist, quantitative methods for comparing these datasets...
Article
Full-text available
Previous quantitative assessments of the crocodylians' dermal bone ornamentation (this ornamentation consists of pits and ridges) has shown that bone sculpture results in a gain in area that differs between anatomical regions: it tends to be higher on the skull table than on the snout. Therefore, a comparative phylogenetic analysis within 17 adult...
Article
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The late Campanian-early Maastrichtian site of Lo Hueco (Cuenca, Spain) has provided a set of well-preserved crocodyliform skull and lower jaw remains, which are described here and assigned to a new basal eusuchian taxon, Lohuecosuchus megadontos gen. et sp. nov. The reevaluation of a complete skull from the synchronous site of Fox-Amphoux (Departm...
Article
An isolated supraoccipital from the late Miocene of Chiapas, southern Mexico, can be referred to Caimaninae, a group including the living caimans and their closest extinct relatives. It shares a polygonal shape, indicating lateral contact with the squamosals, with extant Caiman and Melanosuchus, but some extinct caimanine lineages had a similar mor...
Article
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To provide context for the diversification of archosaurs--the group that includes crocodilians, dinosaurs, and birds--we generated draft genomes of three crocodilians: Alligator mississippiensis (the American alligator), Crocodylus porosus (the saltwater crocodile), and Gavialis gangeticus (the Indian gharial). We observed an exceptionally slow rat...
Article
Full-text available
To provide context for the diversification of archosaurs—the group that includes crocodilians, dinosaurs, and birds—we generated draft genomes of three crocodilians: Alligator mississippiensis (the American alligator), Crocodylus porosus (the saltwater crocodile), and Gavialis gangeticus (the Indian gharial). We observed an exceptionally slow rate...
Conference Paper
Full-text available
Although the European dinosaur succession during the latest Cretaceous and its relationship with the Cretaceous/Paleogene (K/Pg) mass extinction has been the focus of recent work, studies on other nonmarine vertebrates, such as crocodylomorphs, are scarce. Eusuchians first appear during the Barremian and had largely replaced continental non-eusuch...
Article
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The phylogenetic position of the Indian gharial (Gavialis gangeticus) is disputed - morphological characters place Gavialis as the sister to all other extant crocodylians, whereas molecular and combined analyses find Gavialis and the false gharial (Tomistoma schlegelii) to be sister taxa. Geometric morphometric techniques have only begun to be appl...
Article
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Early Miocene deposits from the Domo de Zaza locality, in the south-central Cuban province of Sancti Spiritus, preserve crocodyliform remains, including compressed serrated teeth closely resembling those of South American sebecids. Fragmentary cranial and mandibular material is more difficult to assess. Referral to any other post-Paleogene crocodyl...
Article
Crocodylians are known to consume and modify bones, but actualistic observations of their bite marks have been limited to forensic case studies and surveys of two taxa: Crocodylus niloticus and Crocodylus porosus. To further explore patterns of crocodylian bite mark expression, we conducted a survey of traces left by Alligator mississippiensis. We...
Article
Full-text available
Background: Discovery of Eocene non-marine vertebrates, including crocodylians, turtles, bony fishes, and mammals in Canada's High Arctic was a critical paleontological contribution of the last century because it indicated that this region of the Arctic had been mild, temperate, and ice-free during the early - middle Eocene (∼53-50 Ma), despite be...
Article
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That TAXONOMY should be phylogenetic—i.e., that named taxa should be restricted to monophyletic groups—is widely accepted throughout systematic biology. A recently proposed phylogenetic nomenclatural system (de Queiroz and Gauthier, 1990, 1992, 1994; Cantino and de Queiroz, 2000) goes further by specifying that all supraspecific taxon names be expl...
Conference Paper
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The slender-snouted Campanian through Ypresian “thoracosaurs” are currently viewed as early relatives of the living Indian gharial (Gavialis gangeticus), which is the focus of an unresolved phylogenetic conflict between morphological and molecular data sets. However, substantial stratigraphic and morphological gaps exist within thoracosaurs and bet...
Conference Paper
Full-text available
The radiation of modern crocodiles is a topic of intense debate in the literature. Some of the taxa directly involved in the interpretation of the radiation of the crown-group Crocodylia come from the European Late Cretaceous. However, the recent discovery of new taxa and review of the phylogenetic position of some of them are changing the role of...
Article
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Eusuchians with deep snouts and labiolingually compressed teeth are known from the Palaeogene of Laurasia. These are usually referred to Pristichampsinae, but the type species, Pristichampsus rollinati, is based on insufficiently diagnostic material and should be treated as a nomen dubium. At least two Lutetian species formerly referred to Pristich...
Article
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We describe a new crocodile, Crocodylus thorbjarnarsoni, sp. nov., on the basis of skulls and jaws from Pliocene and Pleistocene deposits in the Lake Turkana Basin of Kenya. The new species has a comparatively broad, deep snout and resembles an extinct horned crocodile from the Quaternary of Olduvai Gorge (C. anthropophagus), but the squamosal ‘hor...
Article
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A lower jaw and associated postcranial remains from the Late Cretaceous–early Paleocene Hornerstown Formation of New Jersey form the basis of a new crocodyliform species, Borealosuchus threeensis. Although one of the oldest known species of Borealosuchus, phylogenetic analysis supports a closer relationship to Borealosuchus from the early Eocene th...
Article
Cranial fragments associated with the holotype of Necrosuchus ionensis reveal a dorsally shifted foramen aereum on the quadrate and a long, slender descending process of the exoccipital lateral to the basioccipital and approaching the basioccipital tubera. The former suggests that Necrosuchus is an alligatoroid and not a crocodylid, as first sugges...
Article
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Tsoabichi greenriverensis, tax. nov., is based on cranial and postcranial remains from the lower Eocene (Wasatchian) Green River Formation of Wyoming. Casts of additional material in private collections include the complete skeleton of an immature specimen. It has abrupt supratemporal fenestral rims, extensive supraoccipital exposure on the skull t...
Article
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![Figure][1] Deccan plateau basalts. Lava from Deccan volcanism formed distinct layering. CREDIT: GSFC/NASA In the Review “The Chicxulub Asteroid Impact and Mass Extinction at the Cretaceous-Paleogene boundary” (P. Schulte et al. , 5 March, p. [1214][2]), the terminal Cretaceous
Data
List of characters and character matrix used in this analysis. (0.06 MB DOC)
Article
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The fossil record reveals surprising crocodile diversity in the Neogene of Africa, but relationships with their living relatives and the biogeographic origins of the modern African crocodylian fauna are poorly understood. A Plio-Pleistocene crocodile from Olduvai Gorge, Tanzania, represents a new extinct species and shows that high crocodylian dive...
Article
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The skull of a mature specimen of Tyrannosaurus rex in the Field Museum of Natural History (FMNH PR2081, ‘‘Sue’’) was recently subjected to high-resolution computed tomographic (CT) analysis, and an endocast was generated without physical damage to the skull. It improves upon endocasts made through hemisection for the tyrannosaurids Tyrannosaurus (...
Article
Phylogenetic analysis indicates that Crocodylus robustus Grandidier & Vaillant, 1872 is more closely related to the living African dwarf crocodiles (Osteolaemus) than to living Crocodylus. The type series cannot be identified, but the original description includes details consistent with known specimens that almost certainly pertain to the same spe...
Article
The holotype of Dollosuchus dixoni (Owen) from the Early–Middle Eocene Bracklesham Beds of England is a set of mandibular fragments that cannot be distinguished from corresponding parts of other longirostrine crocodylians. An isolated humerus from the Bracklesham Beds is consistent with a gavialoid, but it cannot be referred to the holotype of D. d...
Article
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The Indian gharial (Gavialis gangeticus) is not found in saltwater, but the geographical distribution of fossil relatives suggests a derivation from ancestors that lived in, or were at least able to withstand, saline conditions. Here, we describe a new Oligocene gharial, Aktiogavialis puertoricensis, from deltaic-coastal deposits of northern Puerto...
Article
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Fragmentary fossils from northwestern Puerto Rico document the existence of crocodyliforms during the Late Oligocene and Early Miocene. The remains are insufficient to establish new named species, but they are inconsistent with any other crocodylian known from the western hemisphere during the Cenozoic, including extant Alligator and Crocodylus. Th...
Article
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251-268 http://deepblue.lib.umich.edu/bitstream/2027.42/48660/2/ID527.pdf
Article
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A partial skull from the early Eocene London Clay of the Isle of Sheppey, England, is referable to the gavialoid clade Eosuchus, otherwise known from the late Paleocene of continental Europe and North America. It differs slightly from Paleocene forms, but there is insufficient material on which to base a new species. This extends the range of Eosuc...
Article
Full-text available
A partial skull from the early Eocene London Clay of the Isle of Sheppey, England, is referable to the gavialoid clade Eosuchus, otherwise known from the late Paleocene of continental Europe and North America. It differs slightly from Paleocene forms, but there is insufficient material on which to base a new species. This extends the range of Eosuc...
Article
Full-text available
A new crocodylid is described on the basis of fragmentary, but diagnostic, material from the Quaternary of Aldabra Atoll. It differs from all other known crocodylians, living or extinct, in having a prominent semicircular crest, or “horn,” on the dorsolateral margin of the squamosal. Unlike the horns seen in some living Crocodylus, the apex of each...
Article
Recently, the phylogenetic placement of the African slender snouted crocodile, Crocodylus cataphractus, has come under scrutiny and herein we address this issue using molecular and morphological techniques. Although it is often recognized as being a "basal" form, morphological studies have traditionally placed C. cataphractus within the genus Croco...