Tuesday, October 13, 2015

From pterosaur to primitive bird

Here is a draft of the lineage from pterosaur to primitive bird (click to enlarge):

This shows the transition from pterosaur to flying primitive birds and it also shows how the alvarezsaurids and oviraptors fit in as secondarily flightless primitive birds.

Connection of Rhamphorhynchoid pterosaurs to primitive birds:

Oviraptors as secondarily flightless primitive birds:

Connection of Jeholornis and Oviraptors:

If anyone has a comment or a question, please feel free to submit it.

Monday, October 12, 2015

Jeholornis and Oviraptors

I suggest that secondarily flightless oviraptors descended (in both senses) from a flying creature like Jeholornis. Notice the similarities in morphology, time and location.

Jeholornis (meaning "Jehol bird") is a genus of avialans that lived between approximately 122 and 120 million years ago during the early Cretaceous Period in China. Fossil Jeholornis were first discovered in the Jiufotang Formation in Hebei Province, China (in what was previously Rehe Province, also known as Jehol—hence the name) and additional specimens have been found in the older Yixian Formation.[1] Jeholornis had long tails and few small teeth, and were approximately the size of turkeys,[2] making them among the largest avialans known until the Late Cretaceous. Their diet included seeds of cycadsGinkgo or similar plants. Jeholornis were relatively large, primitive avialans, with a maximum adult length of up to 80 cm (2.6 ft).[2] Their skulls were short and high, similar to other primitive avialans like Epidexipteryx and to early oviraptorosaurs like Incisivosaurus.
Avialae is also occasionally defined as an apomorphy-based clade (that is, one based on physical characteristics). Jacques Gauthier, who named Avialae in 1986, re-defined it in 2001 as all dinosaurs that possessed feathered wings used in flapping flight, and the birds that descended from them.[8][9]
Oviraptorosaurs ("egg thief lizards") are a group of feathered maniraptoran dinosaurs from the Cretaceous Period of what are now Asia and North America. They are distinct for their characteristically short, beaked, parrot-like skulls, with or without bony crests atop the head. They ranged in size from Caudipteryx, which was the size of a turkey, to the 8 metre long, 1.4 ton Gigantoraptor.[4] The group (along with all maniraptoran dinosaurs) is close to the ancestry of birds. Analyses like those of Maryanska et al (2002) and Osmólska et al. (2004) suggest that they may represent primitive flightless birds.[5][6]
Caudipteridae is a family of oviraptorosaurian dinosaurs known from the Early Cretaceous of China. Found in the Yixian and Jiufotang Formations, the group existed between 125-120 million years ago.
Protarchaeopteryx (meaning "before Archaeopteryx") is a genus of turkey-sized feathered theropod dinosaur from China.[1] Known from the Jianshangou bed of the Yixian Formation, it lived during the early Aptian age of the Early Cretaceous, approximately 124.6 million years ago.[2]



"Maniraptors" were either secondarily flightless avialae or secondarily flightless non-avialae paraves.
In either case, they descended from flying ancestors. They are not transitional between dinosaurs and Paraves.

Sunday, October 11, 2015


There are many problems with the analyses of the dino to bird theory. Here is one of them:

Also, the use of bipedal coelurosaurian
outgroups, as in the analysis by Clark et
al. (2002), may be contributing to a potentially
misleading topology. Outgroup choice determines
the polarity of character states, including
ancestral reconstructions for entire clades (Nixon
and Carpenter 1993). In this case, using bipedal
cursors as outgroups may obscure phylogenetic
signal by wrongly treating characters indicating
flight loss as plesiomorphy.
The "maniraptors" such as oviraptors and alvarezsaurids were flightless. They lived on the ground. The question is whether their ancestor was a ground-living creature (such as a dinosaur) or whether their ancestor was a flying, primitive bird.
When a cladistic analysis uses a ground-based dinosaur (eg. allosaurus) as the outgroup it takes the flightlessness of the "maniraptors" as being inherited from a dinosaur lineage, when in fact they actually descended (in both senses) from a flying primitive bird ancestor.

Sunday, October 4, 2015


The ancestor of primitive birds was a rhamphorhynchoid pterosaur much like Jeholopterus or Pterorhynchus.
The earliest primitive birds were the feathered, flying creatures with long-bony-tails, such as the scansoriopterygids.

The scansoriopterygids would have lived alongside synapsids such as the aquatic Castorocauda and arboreal gliding mammal Volaticotheriumthe rhamphorhynchoid pterosaurs Jeholopterus and Pterorhynchus, as well as a diverse range of insect life (including mayflies and beetles) and several species of salamander.[14][15]
The [Epidendrosaurus] material described in this paper was collected from a new locality, Daohugou, in east Nei Mongol, northeast China, which is west of Liaoning Province. Many salamanders(Wang 2000), plants and insects (Zhang 2002)have recently been discovered from this new locality. It is notable that an anurognathid rhamphorhynchoid pterosaur [Jeholopterus] with beautiful hair [pycnofibers] covering the whole body has also been reported from this locality (Wang et al. 2002). The estimated age of the deposit at this locality is very controversial and ranges from the Middle Jurassic or the Early Cretaceous according to various authors (Wang etal. 2000; Zhang 2002); however, most workers currently regard it as being Late Jurassic.

Two other Chinese specimens were reported with integumental covering, coming from the same stratum (the Daohugou Bed) as Jeholopterus. So far we have not had the opportunity to examine this material. The first one is a small unnamed anurognathid with extensive preservation of soft tissue, including fibres that have been interpreted as protofeathers (Ji & Yuan 2002). The published pictures show that the soft tissue interpreted as protofeathers is of the same nature as the pycnofibres of Jeholopterus. 

At least some pterosaurs had hair-like filaments known as pycnofibres on the head and body, similar to, but not homologous (sharing a common structure) with, mammalian hair. Though a fuzzy "integument" (natural covering/outer coat) "was first reported in 1831" by Goldfuss,[29] recent pterosaur finds and the technology for histological and ultraviolet examination of pterosaur specimens have provided incontrovertible proof: pterosaurs had pycnofibre coats. Pycnofibres were not true hair as seen in mammals, but a unique structure that developed a similar appearance. Although, in some cases, actinofibrils (internal structural fibres) in the wing membrane have been mistaken for pycnofibres or true hair, some fossils such as those of Sordes pilosus (which translates as "hairy demon") and Jeholopterus ninchengensis do show the unmistakable imprints of pycnofibres on the head and body, not unlike modern-day bats, another example of convergent evolution.[21] The head-coats do not cover the pterosaur's large jaws in many of the specimens found so far.[29]
Jeholopterus was a small anurognathid pterosaur from the Middle to Late Jurassic[1] Daohugou Beds of the Tiaojishan Formation of Inner MongoliaChina , preserved with hair-like pycnofibres and skin remains.

We report a new and nearly completely articulated rhamphorhynchoid pterosaur, Jeholopterus ningchengensis gen. et sp. nov., with excellently preserved fibres in the wing membrane and “hairs” [pycnofibers] in the neck, body and tail regions. Many of its characteristics such as a short neck, short metacarpals and distinctively long fifth pedal digit are characteristic of rhamphorhynchoids. The new species can be further referred to the ‘strange’ short-tailed rhamphorhynchoid family Anurognathidae. It is much more complete than the other known members of the family, namely, Anurognathus from Solnhofen, Germany, Batrachognathus from Karatau, Kazakhstan, and Dendrorhynchoides from Beipiao, Liaoning Province, China. The new pterosaur also shows that the wing membrane is attached to the ankle of the hind limb. The pedal digits are webbed. Furthermore, the “hair” of Jeholopterus bears some resemblance to the hair-like integumental structures of the feathered dinosaur Sinosauropteryx although there is yet no direct evidence to argue for or against their homology.

A new rhamphorhynchoid [Pterorhynchus] is described with a headcrest that is unprecedented among the long-tailed pterosaurs. The preservation of the headcrest presents significant implications regarding the physical appearance and aerodynamics of all pterosaurs. Also, "hair-like" integumentary structures of this pterosaur are shown to be complex multi-strand structures which presents evidence on the origin of feathers and the possibility of a remarkably early ancestral relationship between pterosaurs and birds.
Pterorhynchus was a genus of rhamphorhynchid "rhamphorhynchoid" pterosaur from the Middle or Late Jurassic-age Daohugou Formation[1] of Inner Mongolia,China.
This type specimen consists of an articulated, nearly complete skeleton with remains of the integument. These included the wing membrane, hair-like structures, a long version of the vane found at the end of "rhamphorhynchoid" tails, and a head crest with both a low bony base and a large keratin extension; the latter feature is unusual in "rhamphorhynchoids" (i.e. basal pterosaurs), the fossils of which do not often show head crests.
The hairs (pycnofibers) were originally described as pinnate, with many strands arising from a single base (calamus), and seen as corresponding to the hypothetical Stage II in the evolution of feathers.

The only known Yi qi fossil was found in rocks assigned to the Tiaojishan Formation, dating to the Callovian-Oxfordian age of the Middle-Late Jurassic,[1] dated to between 165 and 153 million years ago.[3] This is the same formation (and around the same age) as the other known scansoriopterygids Epidexipteryx and Scansoriopteryx.

Darwinopterus (meaning "Darwin's wing") is a genus of pterosaur, discovered in China and named after biologist Charles Darwin. Between 30 and 40 fossil specimens have been identified,[1] all collected from the Tiaojishan Formation, which dates to the middle Jurassic period, 161-160.5 Ma ago.[2] The type species, D. modularis, was described in February 2010.[3] D. modularis was the first known pterosaur to display features of both long-tailed ('rhamphorhynchoid') and short-tailed (pterodactyloid) pterosaurs, and was described as a transitional fossil between the two groups.[4] Two additional species, D. linglongtaensis and D. robustodens, were described from the same fossil beds in December 2010 and June 2011, respectively.[5][6]
Darwinopterus, like its closest relatives, is characterized by its unique combination of basal and derived pterosaurian features. While it had a long tail and other features characteristic of the 'rhamphorhynchoids', it also had distinct pterodactyloid features, such as long vertebrae in the neck and a single skull opening in front of the eyes, the
nasoantorbital fenestra (in most 'rhamphorhynchoids', the antorbital fenestra and the nasal opening are separate).[5]

Turner et al 2012.

For reference:

The Rhamphorhynchoidea forms one of the two suborders of pterosaurs and represent an evolutionary grade of primitive members of this group of flying reptiles. This suborder is paraphyletic in relation to the Pterodactyloidea, which arose from within the Rhamphorhynchoidea, not from a more distant common ancestor.
Plieninger, 1901
Included groups