introducing Ainsley Genieva!

On July 24 we welcomed Baby #5 into the world: Ainsley Genieva!

I am now officially the father of five daughters! *GULP*

the month in snapshots

the storms have been relentless this year; our bartlett pear was struck by
lightning and hewn from its trunk

snuggles with the little ones (Maggie couldn't handle it and fell asleep)

Zoey hit double digits! Our 'little hellion' is now a decade old.

the nights will go as follows

that MSG was hitting Maggie pretty hard

Maggie takes lots of impromptu naps

Naomi was a big help to our midwives (see post above)

the year in books [XI]

This month I wrapped up another gauntlet of Young Earth Creationism books. I find the subject fascinating, though I'm not convinced of the 'Answers in Genesis' take on Genesis 1 and 2. While I find myself leaning towards a 'younger earth' for a variety of reasons - scriptural, philosophical, and scientific reasons - I'm not quite ready to make the leap that we can trace the creation of the world back to 4004 BC.  The Genesis texts are notoriously difficult to interpret, and while I generally promote 'plain sense' readings of Scripture, it's obvious that the prose of the Genesis creation accounts is stock full of imagery, symbolism, apologetic and polemic. It's definitely not a poem, but that doesn't necessarily mean it must be taken as 'straight history' in the way that westerners tend to view history. At the same time, I'm convinced that evolution is a bunch of bunk, that Adam and Eve were historical, that Noah's Flood was global in extent and resulted in the reshaping of earth's geology and ecosystems, and that the Tower of Babel was a real event. I'm looking forward to reading more on the subject in the future. 

Dino of the Week: Yangchuanosaurus

Type Species: Yangchuanosaurus shangyouensis

Classification: Dinosauria – Saurischia – Theropoda - Carnosauria - Allosauroidea - Metriacanthosauridae 

Time Period: Middle to Late Jurassic

Location: China 

Diet: Carnivore 

a pair of Huayangosaurus keep a wary eye on a Yuangchuanosaurus

Yangchuanosaurus was the apex predator of China during the Callovian stage of the Middle Jurassic and the Oxfordian stage of the Late Jurassic. It likely preyed upon sauropods such as Mamenchisaurus and Omeisaurus, and it may have dodged spikes and plates to take down stegosaurs such as Tuojiangosaurus and Huayangosaurus. It was similar in size and appearance to the North American Allosaurus, though it was likely slower (top running speed has been clocked around 25 miles per hour). Yangchuanosaurus was a large, powerful carnivore that walked on two muscular legs. The first digit of its foot was a small dewclaw, a vestigial toe that generally grows higher on the leg and doesn’t make contact with the ground when walking. The three outer toes bore its weight, and each was armed with a large claw. Yangchuanosaurus  had short arms, a strong but short neck, a big head with powerful large, and large, serrated teeth. Because its jaws were relatively weak in regards to bite force, it may have brought down prey in the same manner as has been suggested for Allosaurus: the ‘hatchet-bite’ technique in which the attacker swings its head down like a hatchet to club or stun its prey to submission. Yangchuanosaurus  had characteristic growth on top of its nose along with smaller horns and ridges, similar to Ceratosaurus. Its tail made up half its length.

Yangchuanosaurus may have hunted in packs like the North American Allosaurus. While direct evidence is lacking, the similarities between the two theropods imply such behavior wouldn’t be surprising. Adding credibility to the theory is that we have two specimens of this dinosaur, and they are of different sizes (the first’s skull is 2.5 feet long, and the second’s is 3.5 feet long; the first grew to 26 feet in length whereas the second grew up to 36 feet in length); while these differences could be attributed to different ages of the specimens, it could also be due to sexual dimorphism. Sexual dimorphism – wherein one sex has different sizes or morphologies than the other – is often seen in gregarious creatures, and pack-hunting is a facet of gregarious hunters (think: wolves). By hunting in packs, Yangchuanosaurus could bring down large sauropods. The meet of a full-grown Mamenchisaurus could feed the pack for a whole week and still leave some leftovers for scavengers. 

Dino of the Week: Serikornis

Type Species: Serikornis sungei

Classification: Dinosauria – Saurischia – Theropoda - Coelurosauria - Maniraptora - Paraves - Avialae

Time Period: Middle Jurassic

Location: China 

Diet: Insectivorous 

Serikornis is one of the earliest members of Paraves, a group of bird-like dinosaurs that is nevertheless outside the Eumaniraptora clade that includes the deinonychosaurs (such as troodontids and dromaeosaurs) and birds. Serikornis’ name means ‘Ge Sun’s silk bird,’ in reference to the feather-like body covering evident in the single complete articulated skeleton preserved on a slab in China’s fossil beds. The specimen’s nickname, ‘Silky,’ is given due to the resemblance of the hind-limb filaments to those of the modern Silky breed of chicken. This little critter would’ve been only two feet long beak-to-tail and stood only half a foot at the hips. Serikornis had wispy bundles of feathers along its neck, short and symmetrical vaned feathers on its arms, and both fuzz and long pennaceous feathers (also called ‘contour feathers,’ with a central shaft called a rachis with vanes spreading to either side) on its hind legs. Its tail was covered by filaments and distally by fine tail feathers. 

That Serikornis had feathers isn’t debated; but whether this small dinosaur could fly is another matter entirely. One of the key researchers, Ulysse Lefevre, notes, “The feathering of Serikornis shows for the first time a complete absence of barbules – that is, the microstructures that allow feathers to resist air pressure during wing beats. The plumage is composed of four wings, as with many theropod dinosaurs from China, but it did not allow ‘Silky’ to take off from the ground or from a tree.” According to Lefevre, Serikornis was a ground-hugger incapable of flight. The feathers, then, would’ve provided other functions: perhaps they were for insulation, or they were brightly colored and used in mating displays, intimidation of rivals, species recognition, or warding off predators. But not all paleontologists agree. Bristol University’s Professor Mike Benton argued that the presence of hind wings on its hind legs would’ve been more hindrance than help if Serikornis was fully terrestrial; he writes, “The hind wings would be inconvenient for a ground runner. The long feathers on the thigh and calf would be like very elaborate bell-bottomed trousers, rubbing and catching as the animal walked or ran.” He and others believe that the four-wing arrangement may represent a transitional stage between gliding and powered flight; Serikornis, then, may have been largely arboreal. Serikornis may give us a workable model for the evolution of powered flight, “in which little dinosaurs such as Serikornis clambered into trees, perhaps chasing insects and other small tree-dwellers for food. To escape predators or to get around, they would glide from bough to bough.” So if you were to take a trip into late Middle Jurassic China, you might encounter Serikornis leading its chicks on the ground – or perhaps you’d see them flying bough-to-bough in the conifer branches high above your head. Because we don’t have a time machine, we’ll never know for sure. 

Dino of the Week: Monolophosaurus

Type Species: Monolophosaurus jiangi

Classification: Dinosauria – Saurischia – Theropoda - Tetanurae

Time Period: Middle Jurassic

Location: China 

Diet: Carnivore 

Monolophosaurus is named for the single crest atop its skull. This medium-sized predator reached about eighteen feet in length and stood six feet tall at the hips. It had sharp, serrated teeth and a large but skinny head. Its remains were found in fossil rocks containing traces of water, so it may have hunted along lake shores or in coastal regions. Its single crest began on the midline of its snout and continued over the top of its skull to the frontal bones. The top of the crest ran parallel to the upper jaw edge. The frontal bones didn’t contribute to the crest, and they’re unique among theropods in that they have a combined rectangular rather than triangular shape, due to the posterior position of the crest’s rear. Though it had a crest, it wasn’t closely related to the dilophosaurids; in fact, its skeletal anatomy is more closely related to advanced ‘stiff-tailed’ theropods such as Allosaurus. Monolophosaurus may have hunted in packs to take down the sauropods of its day, such as Abrosaurus or Omeisaurus, though pack hunting for this theropod has no evidence in the fossil record; this theory derives from the fact that many early, mid-sized tetanurans such as Allosaurus did, indeed, hunt in packs. 

a pair of Monolophosaurus stalk an ichthyosaur graveyard on a southern Laurasian beach

Dino of the Week: Poekilopleuron

Type Species: Poekilopleuron bucklandii

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

Time Period: Middle Jurassic

Location: Europe (France) 

Diet: Carnivore 

Poekilopleuron was a theropod hunter who roamed the beaches, mangrove swamps, and wooded floodplains of prehistoric France. It was thirty feet long with a low skull that lacked ornamentation. It had short, muscle-chiseled arms that would’ve been strong enough to grapple with thrashing prey. While most early theropods were streamlined in profile, Poekilopleuron was rather bulky like its contemporary Megalosaurus. Though Poekilopleuron would’ve been slow on its feet, it could use its brute and brawn to attack larger prey such as the primitive stegosaur Lexovisaurus and the sauropod Cetiosaurus. Its name means ‘varied ribs’ because one specimen contained a complete ribcage (quite a rarity!) that was comprised of three different types of bone. The length of its middle neck spines suggest to some scientists that it was ancestral in type to the later spinosaurids like Spinosaurus and Baryonyx.