the month in snapshots

Maggie and Ainsley snuggling at naptime 

Ainsley soaking in the world around her

my mini-me loves going to the dentist (for now)

Maggie is our first kid to need stitches.
That ketamine hits hard.

me and the littles

Ainsley likes playing with my beard 

Maggie having fun with her baby sister

early morning snuggles with Maggie and Naomi

the year in books [XII]

Dino of the Week: Piatnitzkysaurus

Type Species: Piatnitzkysaurus floresi

Classification: Dinosauria – Saurischia – Theropoda – Allosauroidea 

Time Period: Middle Jurassic

Location: South America (Argentina)

Diet: Carnivore 

Piatnitzkysaurus was a medium-sized, lightly-built theropod that grew up to twenty-one feet in length. It was the apex predator in its South American environment; it likely hunted smaller dinosaurs, and it may hunted in packs to bring down large sauropods such as Patagosaurus. It probably wasn’t aversive to scavenging the carcasses of dead dinosaurs or marine reptiles that washed onto the beach. Piatnitzkysaurus was discovered in the Canadon Asfalto Formation in Argentina, which gives us an exquisite snapshot of the Callovian stage of the Middle Jurassic. One researcher noted that ‘the fossil record of this formation represents the most completely known biota from the continental Middle to Late Jurassic of the Southern Hemisphere and one of the most complete of the entire world.’ The assemblage of fossils allows us to get a pretty accurate picture of what the environment was like back then. During the late Middle Jurassic and early Late Jurassic, the plants of this area were largely conifers, though ferns are also abundant. Directly beneath the formation is a layer of ash, indicating a nearby volcano (not surprising, given the intense amount of volcanic activity in the Jurassic due to the splitting of the supercontinents). Terrestrial organisms in this lush, tropical environment include the primitive frog Notobatrachus, the turtle Condorchelys, the lizard-like rhynchocephalian Sphenocondor, and a numerous small, early mammals such as Argentoconodon, Asfaltomylos, and Henosferus. The largest creatures were, of course, the dinosaurs. These include the sauropods Patagosaurus and Volkheimeria; the herbivorous heterodont Manidens is also represented, and scientists theorize that it was an arboreal (tree-dwelling) dinosaur due to its feet, which were structured like those of tree-perching birds. Other theropods of the environment included Condorraptor, the abelisaur Eoabelisaurus, and the early allosaur Asfaltovenator. The small pterosaur Allkaruen flitted about the trees above the heads of these terrestrial dinosaurs. 

Dino of the Week: Patagosaurus

Type Species: Patagosaurus fariasi

Classification: Dinosauria – Saurischia – Sauropoda – Gravisauria - Eusauropoda - Cetiosauridae

Time Period: Middle Jurassic

Location: South America (Argentina)

Diet: Herbivore 

Patagosaurus lived in the southwest of Gondwana, and it’s known from several specimens, including one juvenile. This sauropod had a long neck; a small head with a short, high, broad snout; and a very long tail. The juvenile specimen exhibits features different from the adults in the mandible, pectoral girdle, pelvis, and hind limbs. An adult Patagosaurus grew to fifty-four feet in length and weighed seven and a half tons. Its teeth were like those of more derived sauropods, similar in morphology to Euhelopus, being concave on one side and having fairly-expanded crowns; the teeth are also similar to Camarasaurus, though with less concavity and expansion. Patagosaurus’ neural canal of the vertebrae is unique among sauropods, however: starting from the very end of the first vertebra, and extending to almost the end of the third, there’s an enlargement of the canal that forms a well-defined cavity. In a lot of ways Patagosaurus resembled the North American sauropod Haplocanthosaurus, though it was still more primitive. Patagosaurus and its kin may be the direct ancestors of some of the largest Late Jurassic sauropods. Though the continents were splitting and moving farther away from each other, it is possible that towards the end of the Middle Jurassic and the beginning of the Late Jurassic, there were land connections that enabled sauropods to travel between Gondwana and northern Laurasia; this seems to be the case, as members of the same ‘sauropod family’ have been found in these different places.

Patagosaurus was discovered in the Canadon Asfalto Formation in Argentina, which gives us an exquisite snapshot of the Callovian stage of the Middle Jurassic. One researcher noted that ‘the fossil record of this formation represents the most completely known biota from the continental Middle to Late Jurassic of the Southern Hemisphere and one of the most complete of the entire world.’ The assemblage of fossils allows us to get a pretty accurate picture of what the environment was like back then. During the late Middle Jurassic and early Late Jurassic, the plants of this area were largely conifers, though ferns are also abundant. Directly beneath the formation is a layer of ash, indicating a nearby volcano (not surprising, given the intense amount of volcanic activity in the Jurassic due to the splitting of the supercontinents). Terrestrial organisms in this lush, tropical environment include the primitive frog Notobatrachus, the turtle Condorchelys, the lizard-like rhynchocephalian Sphenocondor, and a numerous small, early mammals such as Argentoconodon, Asfaltomylos, and Henosferus. The largest creatures were, of course, the dinosaurs. These include the sauropods Patagosaurus and Volkheimeria; the herbivorous heterodont Manidens is also represented, and scientists theorize that it was an arboreal (tree-dwelling) dinosaur due to its feet, which were structured like those of tree-perching birds. Theropods of the environment included Condorraptor, the abelisaur Eoabelisaurus, and the early allosaur Asfaltovenator. The apex predator of the day was Piatnitzkysaurus, who grew as large as the Late Jurassic Allosaurus and was the prime menace to South American herbivores. The small pterosaur Allkaruen flitted about the trees above the heads of these terrestrial dinosaurs. 

Dino of the Week: Wiehenvenator

Type Species: Wiehenvenator albati

Classification: Dinosauria – Saurischia – Theropoda – Carnosauria - Megalosauroidea - Megalosauria - Megalosauridae - Megalosaurinae

Time Period: Middle Jurassic

Location: Europe (Germany)

Diet: Carnivore 

Wiehenvenator was a two-ton, thirty-foot-long megalosaurid from Germany. It was larger than its English cousin Megalosaurus and was one of the largest Middle Jurassic theropods (and one of the largest European theropods in general). It’s known from a single specimen that was nine to ten years old when it met a watery grave in the warm, shallow North Sea. Its remains were discovered in the Ornatenton Formation, a marine deposit which stretches from the Eastern Alps to the Rhine Valley. Numerous marine fossils have been uncovered in the formation, including bones belonging to the pliosaur Liopleurodon and the oceangoing crocodylomorph Metriorhynchus. At this point in the Jurassic, Germany was riddled with bays and inlets from the shallow and sub-tropical North Sea; western France and Germany were a series of archipelagos bordering the flurry of wooded islands of England. Wiehenvenator was the apex predator among these German archipelagos; its teeth were recurved with the root making up more than two-thirds of the tooth length. The largest teeth measured slightly more than five inches in length. Research Dr. Rauhut notes, ‘Apparently there was in these islands [of Germany] a wide range of sometimes very large predators mainly from the group of Megalosauroidea as finds from France and England, as well as the new predators from Germany show. The Megalosauroidea were the first giant predatory dinosaurs of Earth’s history’ – and Wiehenvenator was the tyrant of them all. Sadly, Wiehenvenator’s legacy wouldn’t last, as the Late Jurassic saw the demise of the megalosaurids and the rise of the coelurosaurs and allosaurs. 

Dino of the Week: Proceratosaurus

Type Species: Proceratosaurus bradleyi

Classification: Dinosauria – Saurischia – Theropoda – Tetanurae – Coelurosauria – Tyrannosauroidea - Proceratosauridae

Time Period: Middle Jurassic

Location: Europe (England)

Diet: Carnivore 

Proceratosaurus was a ten-foot-long theropod that had a slender body and a crest on its snout; the crest likely served display purposes for mating and species recognition. This theropod prowled the wooded islands of prehistoric England, and it lived alongside sauropods such at Cetiosauriscus, the stegosaur Lexovisaurus, the early ornithopod Callovosaurus, and the early ankylosaur Sarcolestes. Though it was originally classified as an ancestor of the Late Jurassic Ceratosaurus, due to the similarity of their snout crests, it’s now consider a coelurosaur, an emerging theropod lineage that overtook the dominant megalosaurs in the Late Jurassic. Not only that, but Proceratosaurus is also considered the earliest tyrannosaur. The Tyrannosauroids emerged in Laurasia in the Jurassic Period, and Proceratosaurus is the earliest known. By the end of the Cretaceous Period, tyrannosauroids were the dominant terrestrial predators in the northern hemisphere. Tyrannosauroid fossils have been discovered in North America, Europe, Asia, South America, and Australia, implying that they diversified and succeeded worldwide. Tyrannosauroids came in many shapes and sizes and are characterized by numerous skeletal features, especially in the skull and pelvis. They emerged in the Jurassic as small theropods with long, three-fingered forelimbs; tyrannosauroids of the Late Cretaceous blossomed to massive sizes and became some of the largest terrestrial predators the planet’s ever seen (these ‘giant’ tyrannosauroids, such as the infamous Tyrannosaurus, lost the long, three-fingered forelimbs to short, two-fingered ones). Primitive feathers have been identified in two species and may have been present in other tyrannosauroids, too. Many species – such as Proceratosaurus – had bony crests in many shapes and sizes, and these likely served for display. 

Dino of the Week: Callosaurus

Type Species: Callovosaurus leedsi

Classification: Dinosauria – Ornithischia – Ornithopoda – Iguanodontia – Dryosauridae 

Time Period: Middle Jurassic

Location: Europe (England)

Diet: Herbivore 

The left thigh bone of the herbivorous ornithopod Callovosaurus was discovered in the Oxford Clay Formation in England. This formation represents the shallow sea that cut among the wooded islands of prehistoric England. This specimen was washed out to sea, where it was likely scavenged by marine reptiles, oceangoing crocodylomorphs, and sharks. Its bones were disarticulated, and its heavy left thigh bone was covered in sediment and became fossilized. Callovosaurus lived among the many islands of England, and as a small herbivore reaching only about eight feet in length, it would’ve browsed on low growing plants. It shared its ecosystem with the sauropod Cetiosauriscus, the stegosaur Lexovisaurus, and the early ankylosaurs Sarcolestes. It would’ve kept a wary eye out for the ten-foot-long theropod Proceratosaurus. Callovosaurus is considered one of the earliest iguanodontian dinosaurs, and many consider a basal iguanodontid. The clade Iguanodontia was an early classification in the dinosaur family tree, including such heavy-hitting ornithopods as Camptosaurus, Iguanodon, and Tenontosaurus, along with the ‘duck-billed’ dinosaurs. It was one of the most diverse and widespread dinosaur groups of the Cretaceous Period, but it got its start halfway through the Jurassic. Though Iguanodontia is considered an informal clade nowadays, as cladistics has advanced and morphed as it is wont to do, it is nevertheless used in regular parlance to refer to ornithopod dinosaurs of certain stripes.