[Paleontology • 2019] Globidens simplex • Insights Into the Anatomy and Functional Morphology of Durophagous Mosasaurines (Squamata: Mosasauridae) from A New Species of Globidens from Morocco

Globidens simplex 

Leblanc, Mohr & Caldwell, 2019

DOI:  10.1093/zoolinnean/zlz008  

  twitter.com/AaronLeBlanc6

Abstract

Durophagous mosasaurs are rare members of Late Cretaceous marine faunal assemblages and new fossil discoveries can shed light on their anatomy, functional morphology and evolutionary history. Here we describe a new species in the durophagous genus Globidens from the Maastrichtian phosphate deposits of Morocco, based on a partial disarticulated skull and cervical vertebral series. This new species shares many anatomical similarities with the only other described Maastrichtian species, G. phosphaticus, but differs in several key features, including the absence of pronounced swellings and sulci on the crushing teeth and the absence of cervical zygosphenes and zygantra. Histological thin sections of a rib from the holotype show that this was not a juvenile individual and reveal osteosclerotic-like bone compactness for the first time in a paddle-bearing mosasaurine. We interpret the highly compact ribs, as well as several peculiarities of the temporal arcade and lower jaws, as adaptations to a diet of benthic, hard-bodied prey.

Keywords: Cretaceous, fossil, Globidensini, histology, Mosasaurinae

Systematic palaeontology 

Reptilia Linnaeus, 1758 

Squamata Oppel, 1811 

Mosasauridae Gervais, 1853

 Mosasaurinae Gervais, 1853 

Globidens Gilmore, 1912 

Globidens simplex Leblanc, Mohr & Caldwell, sp. nov.

Etymology: The epithet simplex is Latin for ‘simple’ or ‘plain’, referring to the simple shapes of the large crushing tooth crowns relative to other species of Globidens, as well as the absence of accessory vertebral articulations (zygosphenes and zygantra) on the cervical vertebrae.

 Globidens simplex sp. nov. MHNM.KHG.221, holotype dental series

  Partial skull reconstruction of Globidens simplex sp. nov. Grey outline represents hypothetical soft tissue and life reconstruction, in addition to the maxilla and upper tooth row.  

 Globidens simplex sp. nov. MHNM.KHG.221, holotype rib, general histology.  

Aaron R. H. Leblanc, Sydney R. Mohr and Michael W. Caldwell. 2019. Insights Into the Anatomy and Functional Morphology of Durophagous Mosasaurines (Squamata: Mosasauridae) from A New Species of Globidens from Morocco. Zoological Journal of the Linnean Society. zlz008. DOI:  10.1093/zoolinnean/zlz008   

the inside of a rib of the newly discovered species of shell-crushing mosasaur, Globidens simplex. The ribs are almost completely filled with bone, making them very dense. This may have helped this animal sink to the seafloor and forage for food!

 twitter.com/AaronLeBlanc6/status/1108535537143410689

 twitter.com/AaronLeBlanc6/status/1109091614872555523

 twitter.com/bone_sharpe/status/1108824866868940801

[PaleoMammalogy • 2017] Anatoliadelphys maasae • Skeleton of An Unusual, Cat-sized Marsupial Relative (Metatheria: Marsupialiformes) from the middle Eocene (Lutetian) of Turkey

Anatoliadelphys maasae  Maga & Beck, 2017

 DOI: 10.1371/journal.pone.0181712 

Abstract

We describe a near-complete, three-dimensionally preserved skeleton of a metatherian (relative of modern marsupials) from the middle Eocene (Lutetian: 44–43 million years ago) Lülük member of the Uzunçarşıdere Formation, central Turkey. With an estimated body mass of 3–4 kg, about the size of a domestic cat (Felis catus) or spotted quoll (Dasyurus maculatus), it is an order of magnitude larger than the largest fossil metatherians previously known from the Cenozoic of the northern hemisphere. This new taxon is characterised by large, broad third premolars that probably represent adaptations for hard object feeding (durophagy), and its craniodental morphology suggests the capacity to generate high bite forces. Qualitative and quantitative functional analyses of its postcranial skeleton indicate that it was probably scansorial and relatively agile, perhaps broadly similar in locomotor mode to the spotted quoll, but with a greater capacity for climbing and grasping. Bayesian phylogenetic analysis of a total evidence dataset comprising 259 morphological characters and 9kb of DNA sequence data from five nuclear protein-coding genes, using both undated and “tip-and-node dating” approaches, place the new taxon outside the marsupial crown-clade, but within the clade Marsupialiformes. It demonstrates that at least one metatherian lineage evolved to occupy the small-medium, meso- or hypo-carnivore niche in the northern hemisphere during the early Cenozoic, at a time when there were numerous eutherians (placentals and their fossil relatives) filling similar niches. However, the known mammal fauna from Uzunçarşıdere Formation appears highly endemic, and geological evidence suggests that this region of Turkey was an island for at least part of the early Cenozoic, and so the new taxon may have evolved in isolation from potential eutherian competitors. Nevertheless, the new taxon reveals previously unsuspected ecomorphological disparity among northern hemisphere metatherians during the first half of the Cenozoic.

Systematic palaeontology

Mammalia; Theria

Metatheria; Marsupialiformes

Anatoliadelphys gen. nov.  

Anatoliadelphys maasae sp. nov.  

Etymology: Anatolia (Greek): the geographic name for the Asian part of Turkey; delphys (Greek): uterus, a common suffix for marsupials and their fossil relatives; maasae: in honour of Dr. Mary Maas and her contributions to Paleogene mammalian palaeontology, particularly in Turkey.

Holotype: Ankara Üniversitesi Jeoloji Müzesi (AÜJM) specimen 2002–25, which comprises a fragmented partial cranium, both dentaries, and associated postcranial elements, including most of the vertebral column, partial pectoral and pelvic girdles, all of the long limb bones, both calcanei, two metapodials, and a few phalanges.

Locality and age: AÜJM 2002–25 was collected from the Lülük member of the Uzunçarşıdere Formation (UCF), which is part of the small Orhaniye-Güvenç sedimentary basin located at the northwestern edge of the city of Ankara, approximately 5 km southwest of the town of Kazan, in central Turkey. The Lülük member is the lowest of the three members currently recognised within the UCF (together with the Gökdere [middle], and Sarıbeyler [upper] members), and is the source of all fossil mammals known from the UCF to date. AÜJM 2002–25 is from locality AK33, which is approximately 90m above the base of the UCF, at Memlik village. Until recently, the age of the UCF was poorly constrained, but a combination of U-Pb dating of zircons and magnetostratigraphy now support a date of 44–42 MYA (= Lutetian) for the formation as a whole, and 44–43 MYA for the Lülük member.

Diagnosis: Anatoliadelphys maasae differs from all other metatherians in the following combination of features: comparatively large size (estimated body mass 3–4 kg); premolars increase markedly in size posteriorly (occlusal area of p1 less than one sixth that of p3); P3 and p3 very large (similar in occlusal area to M2 and m2 respectively) and also broad (labiolingual width:mesiodistal length ratio is 0.89 for P3 and 0.7 for p3); modified tribosphenic molar dentition, in which M1-3 and m1-4 increase markedly in size posteriorly (occlusal area of M1 approximately one third that of M3; occlusal area of m1 approximately one seventh that of m4); upper molars with cingula extending along the anterior and posterior margins; protocone large but conules indistinct or absent; metacone taller than the paracone on M3 but smaller than the paracone on M4; centrocrista v-shaped on M3, with the premetacrista extending labially to stylar cusp D; centrocrista straight on M4; parastylar lobe very large on M4; anterior cingulid weakly developed on m3-4; m4 trigonid dominated by enormous protoconid, with paraconid and metaconid both greatly reduced; preentocristid and cristid obliqua of m3-4 both with carnassial notch; posterior cingulid present but very faint on m3-4; strongly curved radius and tibia; femur with prominent third trochanter, well-marked trochlea and distal condyles of approximately equal width; calcaneus with medially-inflected tuber, large peroneal process with prominent groove for peroneus longus tendon, concave calcaneocuboid facet, and prominent pit (probably for plantar calcaneocuboid ligament) on ventral surface.

.....

Fig 1. Holotype skeleton of Anatoliadelphys maasae (AÜJM 2002–25). Scale bar = 5 cm. 

Reconstruction of the Anatoliadelphys maasae.

Illustration: Peter Schouten 

A. Murat Maga and Robin M. D. Beck. 2017. Skeleton of An Unusual, Cat-sized Marsupial Relative (Metatheria: Marsupialiformes) from the middle Eocene (Lutetian: 44-43 million years ago) of Turkey.  PLoS ONE. 12(8); e0181712.  DOI: 10.1371/journal.pone.0181712

Cenozoic carnivore from Turkey may have evolved without placental competitors  phy.so/422094230 via @physorg_com

Ancient Carnivorous Dread-Possum Is Upending The History Of Mammals | Gizmodo Australia (via @GizmodoAU)  www.gizmodo.com.au/2017/08/ancient-carnivorous-dread-possum-is-upending-the-history-of-mammals/

[Paleontology • 2017] Owadowia borsukbialynickae • A New Pancryptodiran Turtle from the Late Jurassic of Poland and Palaeobiology of Early Marine Turtles

 Owadowia borsukbialynickae

Szczygielski, Tyborowski & Błażejowski, 2017

DOI: 10.1002/gj.2952 

Abstract

Although Western Europe has yielded numerous Jurassic turtle taxa, several represented by cranial material or complete skeletons, the fossil record of the Jurassic turtles remains scarce to the north and east from Germany. Although some Late Jurassic testudinates were historically described from Poland, they were, thus far, represented by fragmentary remains that never were properly figured or described in detail. Therefore, very little is known about the mid-Mesozoic diversity of turtles in that region of the continent. A new pancryptodiran turtle genus and species, Owadowia borsukbialynickae, is described from the uppermost Jurassic (Tithonian, ca. 148 Ma) carbonate sediments of the Kcynia Formation in Owadów-Brzezinki Quarry, near Tomaszów Mazowiecki in central Poland. The lower jaw morphology and palaeoecological setting inhabited by the new genus and species, together with the trophic relationships of the Jurassic pancryptodiran turtles, are discussed in an attempt to determine the potential range of mode of life of O. borsukbialynickae. We propose that the new specimen belongs to a new durophagous pancryptodiran turtle taxon. O. borsukbialynickae might have spent considerable time in the marine environment and specialized on eating hard-shelled invertebrates like bivalves and decapod crustaceans, common to that setting.

Figure 5: Owadowia borsukbialynickae, life restoration during feeding on decapod crustacean.

Digital painting by T. Szczygielski 

SYSTEMATIC PALAEONTOLOGY

Order Testudinata Klein, 1760

Pancryptodira Joyce, Parham, & Gauthier, 2004

Incertae sedis

Genus Owadowia gen. nov.

Type species. Owadowia borsukbialynickae sp. nov.

Etymology. Owadowia, from Owadów-Brzezinki Quarry—the locality where remains of this new turtle were found.

Owadowia borsukbialynickae sp. nov.

Etymology. borsukbialynickae, in honour to the Polish palaeontologist, Prof. Magdalena Borsuk-Białynicka—a long time researcher of the Mesozoic reptiles.

Type specimen. ZPAL V/O-B/1959 (Figures 2-4), stored in the collections of the Institute of Palaeobiology, Polish Academy of Sciences in Warsaw, a fragment of the lower jaw, right coracoid, right ilium, and mostly complete right femur.

Type locality. Owadów-Brzezinki Quarry of Nordkalk GmbH, Sławno, close to Tomaszów Mazowiecki (Central Poland). 

Occurrence. Kcynia Formation, Tithonian, Upper Jurassic; the first lithofacial unit within Zaraiskites zarajskensis subzone.

Diagnosis. Relatively large Jurassic turtle (estimated carapace length around 50 cm) with narrow and V-shaped lower jaw, relatively short and wide but pronounced snout, massive, spoon-like symphysis, no symphyseal hook, well-developed triturating surface in the symphyseal area, moderately developed triturating surface with parallel lingual and labial ridges along the mandibular rami, the labial ridge much higher and sharper than the lingual ridge, the lingual ridge only present laterally and gradually disappearing towards the midline of the symphyseal area, splenial large. The triangular, symmetrical coracoid plate without anterior or posterior expansions, the coracoid neck without coracoid foramen. The slender and proximally and distally slightly curved femur with deep, U-shaped intertrochanteric fossa, small fibular condyle and prominent, well-developed tibial condyle. The ilium with expanded ventral end, constricted neck and well-developed, thin dorsal fan with posterior and no anterior expansion, no signs of sutural attachment to the carapace.

CONCLUSIONS

A new pancryptodiran turtle, Owadowia borsukbialynickae, is described from the Tithonian lagoon limestones of Owadów-Brzezinki Quarry, Poland. The most characteristic trait of this new taxon is its expanded triturating surface indicating a durophagous ecology. The morphology of O. borsukbialynickae mandible is unlike that any other Jurassic turtle known thus far, but rather resembles the Cretaceous protostegids and recent cheloniids, which suggests that this turtle might have inhabited a similar trophic niche. While it is possible that O. borsukbialynickae was a semiaquatic or freshwater turtle, the lower jaw morphology and its inferred feeding preferences make such assumption unlikely, and rather suggest that this animal spent a lot of time in a shallow water, possibly marine environment, like Owadów-Brzezinki lagoons. The taphonomic evidence (the quantitative dominance of marine vertebrates in the Owadów-Brzezinki bone-bed, lack of any brackish and freshwater taxa, and absence of transportation) suggests that O. borsukbialynickae was an inhabitant of these lagoons, rather than a terrestrial animal that inhabited the adjacent land. Such assumptions may be supported in the future by new finds and isotope data.


Tomasz Szczygielski, Daniel Tyborowski and Błażej Błażejowski. 2017. A New Pancryptodiran Turtle from the Late Jurassic of Poland and Palaeobiology of Early Marine Turtles. Geological Journal. DOI: 10.1002/gj.2952

[Paleontology • 2015] A Miocene Hyperdiverse Crocodylian Community reveals Peculiar Trophic Dynamics in proto-Amazonian Mega-Wetlands

The massive wetlands once covered the Amazon River basin about 13 million years ago during the late middle Miocene. Three newly discovered species of crocodylians, including Kuttanacaiman iquitosensis (left), Caiman wannlangstoni (right) and Gnatusuchus pebasensis (bottom), look for clams, which they could likely scoop up with their mouths and crunch with their peglike teeth.

Illustration: Javier Herbozo  

Abstract

Amazonia contains one of the world's richest biotas, but origins of this diversity remain obscure. Onset of the Amazon River drainage at approximately 10.5 Ma represented a major shift in Neotropical ecosystems, and proto-Amazonian biotas just prior to this pivotal episode are integral to understanding origins of Amazonian biodiversity, yet vertebrate fossil evidence is extraordinarily rare. Two new species-rich bonebeds from late Middle Miocene proto-Amazonian deposits of northeastern Peru document the same hyperdiverse assemblage of seven co-occurring crocodylian species. Besides the large-bodied Purussaurus and Mourasuchus, all other crocodylians are new taxa, including a stem caiman — Gnatusuchus pebasensis — bearing a massive shovel-shaped mandible, procumbent anterior and globular posterior teeth, and a mammal-like diastema. This unusual species is an extreme exemplar of a radiation of small caimans with crushing dentitions recording peculiar feeding strategies correlated with a peak in proto-Amazonian molluscan diversity and abundance. These faunas evolved within dysoxic marshes and swamps of the long-lived Pebas Mega-Wetland System and declined with inception of the transcontinental Amazon drainage, favouring diversification of longirostrine crocodylians and more modern generalist-feeding caimans. The rise and demise of distinctive, highly productive aquatic ecosystems substantially influenced evolution of Amazonian biodiversity hotspots of crocodylians and other organisms throughout the Neogene.

KEYWORDS: Miocene, caimanine crocodylians, proto-Amazonia, Pebas System, molluscs, durophagy

the newly discovered species Gnatusuchus pebasensis, a crocodylian [13 million years ago] with a short face and rounded teeth that may have shoveled through the mud at the bottom of lakes and swamps to find prey, such as clams and other mollusks. A crocodylian is an order that includes crocodiles, alligators, caimans and gharials 

Model: Kevin Montalbán-Rivera

Figure 4. Phylogenetic position of the Pebasian caimanines within the Alligatoroidea. Time-calibrated, strict consensus cladogram of 70 most parsimonious trees (see electronic supplementary material, figure S6 and test S1). Gnatusuchus pebasensis is the most basal caimanine and Globidentosuchus brachyrostris is the next outgroup to all remaining caimanines; these two taxa reveal unknown character states ancestrally present within the caimans (i.e. long splenial symphysis, posterior globular teeth) and their inclusion influenced the topology of relationships within the caimanine clade. Character support provides a novel sister-grouped relationship between the South American caimans and the North American Cretaceous globidontan alligatoroids (i.e. Brachychampsa, Albertochampsa and Stangerochampsa), whereas prior analyses showed either the monophyly of Alligatoridae (Caimaninae + Alligatorinae) exclusive of Cretaceous globidontans or, more recently, a polytomy within the globidontan alligatoroids (Caimaninae + [alligatorines and Cretaceous globidontans]). Here, this polytomy (dotted lines) is obtained when the alligatorine Allognathosuchus wartheni is excluded from the analysis. Results also suggest an early diversification of major groups within the Caimaninae dating back to the end of the Cretaceous or Palaeocene interval. (a) The Acre Phase (ca 9 Ma) after intense Andean uplift and onset of the transcontinental Amazon River System. (b) The Pebas Mega-Wetland System in northwestern South America during MZ8 (ca 13 Ma). Stratigraphic distribution of taxa (yellow bars for crushing-dentition caimanines, black lines for other taxa) relative to major Neogene stages and events in Amazonia. Palaeogeographical reconstructions, Andean uplift peaks (black triangles) and marine incursions (m) are from Hoorn et al. Molluscan Zones and diversity for the Pebas System (MZ1–12) are from Wesselingh et al. When suitable, internal nodes were time-calibrated with molecular data from Oaks. Darker grey marks MZ8. Alligatoroids are from South America, Asia (AS), Central America (CA), Europe (EU) or North America (NA).

Excavated fossils from Peru show that seven species of crocodylian lived together in the same place at relatively the same time. The skulls and jaws, shown above, are extremely diverse, the researchers said. They include (1) Gnatusuchus pebasensis, (2) Kuttanacaiman iquitosensis, (3) Caiman wannlangstoni, (4) Purussaurus neivensis, (5) Mourasuchus atopus, (6) Pebas Paleosuchus, and (7) Pebas gavialoid.

Reconstructions: Javier Herbozo & Rodolfo Salas-Gismondi

Rodolfo Salas-Gismondi, John J. Flynn, Patrice Baby, Julia V. Tejada-Lara, Frank P. Wesselingh and Pierre-Olivier Antoine. 2015. A Miocene Hyperdiverse Crocodylian Community reveals Peculiar Trophic Dynamics in proto-Amazonian Mega-Wetlands. Proceedings of the Royal Society B.

 http://rspb.royalsocietypublishing.org/content/282/1804/20142490

DOI: 10.1098/rspb.2014.2490

Crocs rocked pre-Amazonian Peru: New research uncovers 7 crocodile species in single 13-million-year-old bone bed http://phy.so/344017318 via @physorg_com

Ancient Croc with 'Shovel Mouth', Likely Enjoyed Clam Dinners, Roamed the Amazon http://shar.es/1WdZVx Photos: http://shar.es/1WdZED via @LiveScience

Three New Prehistoric Caiman Species Found in Peruvian Amazonia: http://www.sci-news.com/paleontology/science-gnatusuchus-pebasensis-three-new-prehistoric-caiman-species-peruvian-amazonia-02536.html