Indices Academiatrum, or, a Dialogue on an AIG Webcast with Jonathan Sarfati, on Avian Phylogeny


Webcast Source: http://www.gospelcom.net/cgi-bin/ram...thUntruths1.rm

1. Introduction

In an interview featured on the website of Answers in Genesis, the Australian creationist organization, Jonathan Sarfati is featured in a discussion concerning the marvelous science of avian phylogenetics. The intent of the Dialogue presented herein is to address multiple aspects of the Sarfati interview and elucidate with all brevity possible, the data, which renders several conclusions offered by Sarfati untenable. Specifically, the authors will focus on the following areas:

a)Theropod aerobic capacity, with particular emphasis on Maniraptoriformes

b)Integumentary structure of Maniraptoriformes

c)Integumentary derivates and exaptation thereof

d)Phylogenetic placement of Mononykus olecranus, Protarchaeopteryx robusta, and Caudipteryx zhoui

e)Comparative body proportions in Theropoda, with particular emphasis on Maniraptoriformes

f)Temporal discontinuity

g)The plesiomorphic osteology of Archaeopteryx lithographica

h)Digital homology

i)Support for theropod origin


2. Aerobic Capacity in Theropoda, with Particular Emphasis on Maniraptoriformes

The principal arguments advanced by Sarfati in this regard during the AIG interview are based on the research of John Ruben of the University of Oregon and his colleagues. Said arguments conclude that Theropoda possessed a pelvovisceral piston in which diaphragmatic musculature anchored to the procumbent pubes operates upon the hepatic capsule, ventilating the lungs (Ruben et al, 1996, 1997, 1998, 1999).

Pelvovisceral systems are further characterized by an airtight post-pulmonary septum inferior to the liver, which preserves a pressure differential between the cranial and caudal aspects of the thorax (Gans & Clark 1976, Perry 1988, 1990). Osteological characters associated with such a system include (following Mook 1921, Gans & Clark 1976, Duncker 1978, Perry 1988, 1990, Ruben et al 1997, Paul 2002):

a) Thoracic ribs articulate with the dorsal vertebrae via hyper-elongated transverse processes and single proximal heads

b) Gastralia do not meet medially, and are instead set in a cartilaginous sheet

c) Pubes mobile, procumbent

d) Lumbar region formed by reduction of the caudal thoracic ribs

e) Sternal ribs doubled

f) Diverticula largely absent, pneumatic excavation of bones inconsistent or absent, most especially caudal to the post-pulmonary septum

Characters a, b, c, and d, are biomechanical necessities of a pelvovisceral pump. The modified rib articulation with the dorsal vertebrae and failure of the gastralia to meet medially permits the cranial aspect of the thorax (superior to the post-pulmonary septum) to present a smooth surface both dorsally and ventrally in which the viscera can readily move in concert with the action of the diaphragmatic musculature. Similarly, such musculature requires mobility and a procumbent orientation of the pubes (and most likely a high breadth ratio). The presence of a lumbar region is consistently observed in all taxa in which a pelvovisceral pump is found, and is therefore most logically considered to be an essential aspect of the system as a whole. The doubling of the sternal ribs assists in regulation of the pelvovisceral mechanism. The absence or inconsistent presence of pneumatic excavation of the bones caudal to the post-pulmonary septum is particularly indicative of such an aerobic system, as the septum maintains a pressure differential between the fore and aft thoracic compartments.

Ruben et al presented their conclusions on the aerobic system present in Theropoda following the 1996 description of the type Sinosauropteryx prima (NGMC 2124) (Ji & Ji 1996) from the Lower Cretaceous Yixian lagerstatten of China, in which a concentration of carbonized material is preserved in the caudal region of the thorax. Ruben and his colleagues identified the material as the liver, and argued that the cranial aspect of this region was convex, demonstrating the presence of a post-pulmonary septum, and thus by inference, a pelvovisceral pump. Ruben et al further asserted that muscle fibers preserved in the type Sinosauropteryx were indicative of the requisite diaphragmatic musculature, inserting on the distal pubes (Ruben et al 1997, Feduccia 1999). Ruben and his colleagues have further maintained that the type Scipionyx samniticus (Sasso & Signore 1998) recovered from Cretaceous strata of Italy validates said claims (Ruben et al 1999).

Ruben et al have relied exclusively on the data available from preserved soft-anatomy, minimizing osteological factors in their analyses (Ruben 1995, Ruben & Jones 2000). The soft anatomy of the type Sinosauropteryx displays an overall poor state of preservation, and thus data derived from this material is largely ambiguous until such time as soft-tissues are found preserved with greater fidelity in similar theropods (Martill et al 2000, Paul 2002).

Due to haphazard and unsupervised preparation of NGMC 2124 by amateurs, the slab was shattered symmetrically into at least twelve pieces (Ji & Ji 1996, Paul 2002), and subsequent restorative measures have largely obscured the original extent and form of the carbonized region (Paul 2002). Breakage and infilling have destroyed the original cranial aspect of the carbonized region, such that its form and the degree to which it extended cranially cannot be ascertained with certainty (Paul 2002). The dorsal, central, and ventral margins identified by Ruben et al (1997) as displaying a convex arc, in fact delineate a pseudo-margin resulting from the inadequate preparation of the specimen. Thus, the initial conclusion that the carbonized material displays a convex arc in cranial aspect is not unequivocally substantiated at this time.

Moreover, the liver of both birds and crocodiles, the two extant nodes of Archosauria, display convex cranial arcs, and the presence of such an arc in and of itself is not indicative of a pelvovisceral system (Duncker 1979, Brackenbury 1987, Paul 1988, Paul 2002). Ruben et al infer a post-pulmonary septum, in concordance with their argument that the carbonized material displays a convex arc in cranial aspect, however, the reason why such a septum must be present given a convex cranial arc, is not clear. Furthermore, the height of the liver (assuming the material represents as much) is not a reliable correlate of a pelvovisceral system. Liver anatomy is highly variable throughout the ontogeny of any given taxon and individual animal, and more germane, there is no consistent difference in the size and position of the liver in crocodiles, and birds (Siwe 1937, Brackenbury 1987, Secor & Diamond 1995, Paul 2002). Curiously, a post-pulmonary septum is observed in none of the remaining Sinosauropteryx material (Ackerman 1998, Chen et al 1998, Paul 2002).

Ruben et al (1997) attempted to mitigate these ambiguities with the soft-anatomy of Sinosauropteryx by arguing that preserved muscle fibers in the type Scipionyx were oriented in a position to be expected of diaphragmatic musculature. However, these fibers—if they are indeed muscle fibers—have subsequently been identified as components of M. obliquus and M rectus, muscles of the abdomini, by virtue of their configuration (Paul 2002).

Further doubt is cast on the conclusions pertaining to the aerobic capacity in Sinosauropteryx made by Ruben and his colleagues, by the soft anatomy of Scipionyx samniticus. In the type Scipionyx, the intestinal tract is preferentially preserved at the expense of other viscera, and a structure immediately caudal to the sternum, distal ends of the humeri and proximal blade of the scapula, is most logically associated with the liver (Sasso & Signore 1998, Ruben et al 1999, Paul 2002). Ironically, the cranial orientation of the liver in Scipionyx is entirely incongruent with the position of the alleged liver in Sinosauropteryx. The position of the intestines in Scipionyx and the carbonized matter in Sinosauropteryx are identical, and given these data, the most logical conclusion is that the latter represents the fossilized post-mortem decay of the intestinal tract (Paul 2002).

Thus, even offering Ruben’s research the benefit of the doubt (i.e., assuming they have identified the carbonized material in Sinosauropteryx correctly), the data presented in Ruben et al (1997, 1999), is not sine qua non verification of a pelvovisceral pump in Theropoda, in that the soft-anatomy is sufficiently ambiguous to render definitive conclusions based on such, wholly speculative at this time.

Given these limitations, the osteological data is currently the most reliable in determining the aerobic faculties of Theropoda. While Ruben (1995) and Ruben & Jones (2000) have argued that osteological factors are largely inconsequential to the operation of aerobic systems, there is no apparent reason why this should be so, and indeed the suite of characters which are biomechanical necessities for the respective systems of aerobic regulation, seem to directly refute this assertion.
Theropoda lack all the osteological modifications permitting the operation of a pelvovisceral pump, and in particular, lack the modification of the proximal heads of the ribs and the communication of the gastralia seen in crocodiles. In Theropoda, the thoracic ribs articulate with moderate or reduced transverse processes of the dorsal vertebrae via bifurcated proximal heads, and thus the dorsal surface of the rib cage in theropods is sharply corrugated (Ostrom 1969, Paul 1988, Britt 1997, Paul 2002). The gastralia meet medially in Theropoda, and were not imbedded within a cartilaginous sheet (Ostrom 1969, Paul 1988, Dodson et al 1990, Paul 2002). These characters would have precluded the formation of a sub-cylindrical, smooth-walled tube in which the viscera could be acted upon by diaphragmatic muscles (Paul 2002), and these data alone, demonstrate that the presence of a pelvovisceral system in Theropoda, was a biomechanical impossibility.

The absence of a lumbar region, inadequacy of the distal pubes to support diaphragmatic musculature and immobility of the pubes (especially in opisthopubic taxa, e.g. Eumaniraptora) further argue against the presence of such a hepatic piston, as is seen in crocodiles (contra Ruben et al).

To preclude the assertion of negative evidence, review of the osteological characters associated with avian or paravian aerobic capacities, which are, or are not present in Theropoda, is germane. Characters associated with the avian aerobic system include (after Zimmer 1935, Bellairs & Jenkin 1960, King 1966, Schmidt-Nielsen 1972, Olson 1973, Perry 1983, Beale 1985, Paul 1988, Perry 1989, McLelland 1989, Bramble & Jenkins 1998, Paul 2002):

a)Postcrania consistently pneumatic, infiltrated by pulmonary diverticula

b)Proximal thoracic rib heads bifurcated, forming a corrugated dorsal rib cage

c)Caudal ribs not reduced

d)Sternocostal hinge present

e)Sternal ribs are singular, not double, and usually ossified

f)Ossified uncinate processes

g)Gastralia meet medially

In Theropoda the postcrania are consistently pneumatized, displaying invasion of pulmonary diverticula. Pneumaticity of postcranial elements extends to the sacrum and caudal vertebrae in some Theropoda (Russell & Dong 1993, Britt 1997, Paul 2002), in contrast to the pattern expected had an airtight post-pulmonary septum existed in life. The proximal heads of the thoracic ribs, in even the most basal Theropoda, are bifurcated and articulate with the dorsal vertebrae via moderate transverse processes, as detailed above. The caudal ribs in Theropoda are not reduced, and consequently, a lumbar region is absent, as detailed above. The sterna and coracoids of avepectoran theropods (i.e., Maniraptoriformes), articulate via a hinge joint permitting sternal kinesis (Paul 1987, 1988, Norell & Makovicky 1999, Burnham et al 2000, Paul 2002). Contrary to Ostrom (1969), the sternal ribs of Maniraptoriformes are singular, and ossified (Barsbold 1983, Paul 1988, Ji et al 1998, Norell & Makovicky 1999, Xu, Wang & Wu 1999, Paul 2002). Ossified uncinate processes are present in derived maniraptoran taxa (Paul 1988, Xu, Wang & Wu, 1999, Norell & Makovicky 1999, Xu et al 2000, Burnham et al 2000, Paul 2002). Lastly, the gastralia of Theropoda meet medially, and were not set in a cartilaginous sheet, as in crocodiles, as detailed elsewhere.

It is thus concluded, that the osteology of Theropoda is inconsistent with the presence of a pelvovisceral pump, and at least in two regards, the operation of such a pump would have been a biomechanical impossibility. On the contrary, all the modifications of the thoracic and pectoral skeleton, as well as the vertebrae seen in Theropoda, are congruent with those observed in Avialae, arguing the presence of a similar aerobic system in at least some theropods. Considering the ambiguity of the soft-anatomy at hand, current analyses must rely on the osteological data until such time as better-preserved soft-tissues become available. These data directly contradict Sarfati’s comments in the interview in question.

2. Integumentary Structure of Maniraptoriformes

Evidence of feathery integument in Theropoda is solely restricted to the clade Maniraptoriformes. The first specimen to provide empirical data suggesting the presence of such integument in this taxon, was the type Sinosauropteryx prima (NGMC 2124) (Ji & Ji 1996), in which tubular integumentary structures are observed from the crown and nape, down the back, and onto the dorsal and ventral aspects of the tail. The integumentary structures also appear to be present on parts of the skull and along the antebrachial margin of the forelimb (Chen et al 1998, Feduccia 1999, Paul 2002). Multiple authors have asserted that these structures represent integumentary fibers, which are precursors to feathers sensu stricto (Ji & Ji 1996, 1997, Chen et al 1998, Griffiths 1998/2000, Paul 2002).

Although Geist et al (1997), Feduccia (1999), and Ruben & Jones (2000) have argued that the integumentary structures are collagenous, there has been no data to substantiate said conclusion presented. The inferred aquatic habitus of compsognathid coelurosaurs (Feduccia 1999) is entirely speculative and directly refuted by the osteology of known compsognathids. Furthermore, the suggestion that sub-dermal collagen fibers can account for the integumentary structures observed in Sinosauropteryx is irreconcilable with the examples of varanid lizards shown by Feduccia (1999, 378). The integumentary structures seen in Sinosauropteryx are most parsimoniously interpreted as keritanaceous (Ji & Ji 1996, 1997, Chen et al 1998, Paul 2002).

The emphasis placed upon the integument of Sinosauropteryx is curious, in that evidence of feathery integument is by no means limited to this theropod. Far more unambiguous are the structures preserved with high fidelity in Sinornithosaurus millenii, Beipiaosaurus inexpectus, Microraptor gui, Caudipteryx zhoui, and Protarchaeopteryx robusta (Ji & Ji 1997, Ackerman 1998, Ji et al 1998, Padian & Chiappe 1998, Xu, Tang & Wang 1999, Sloan 1999, Xu, Wang & Wu 1999, Xu et al 2000, Hoffman 2000, Zhou & Wang 2000, Xu et al 2001, Paul 2002, Currie 2003). The presence of feathery integument is inferred from the presence of ulnar quill knobs in both Rahonavis ostromi, and Unenlagia comahuensis (Novas 1997, Forster, Sampson, Chiappe & Krause, 1998). There has to date been no data presented to refute the presence of feathery integument in these taxa.

Therefore, Sarfati’s comments that there are no feathered Theropoda are lacking in substantiation.


3. Integumentary Derivatives and Exaptation Thereof

Arguments concerning the origin of feathery integument that do not take account of the developmental and molecular data, which has accrued in the past decade, are obsolete. Modern hypotheses advanced for modeling the origin and early development of feathers synthesize data gleaned from developmental processes and the pleiotropic interaction of regulatory genes, and proteins (Brush 1993, 1996, 2000, Ji et al 1998, Padian & Chiappe 1998, Prum 1999, Xu, Tang & Wang 1999, Xu, Wang & Wu 1999, Maderson & Alibardi 2000, Brush 2000, Harris, Fallon & Prum 2002, Prum & Brush 2002, 2003). Research into the developmental stages by which feathers are derived in modern birds had yielded a coherent, incremental developmental model by which the origin and early evolution of feathers can be quantified, and predicted (Prum & Brush 2002, 2003).

Specifically, the influence of regulatory gene Sonic Hedgehog (Shh) and Bone Morphogenetic Protein 2 (Bmp2) at specific times and in specific regions of the epidermal placodes are responsible for the helical growth patterns of the follicle collar and its subsequent differentiation into the rachis ridge, barbule plates, and barb ridges. These data have shown that contrary to classical arguments, feathers can be derived at their most basal level without direct aerodynamic impetus. In other words, the developmental model of feather origins is completely compatible with the exaptation of basal feathers to aerodynamic function (Brush 1993, 1996, 2000, Prum 1999, Brush 200, Harris, Fallon & Prum 2002, Prum & Brush 2002, 2003).

Considering that the most basal feathers are, following a developmental model, predicted to be hollow cylinders arising from epidermal placodes, the presence of such structures on multiple theropod taxa is astounding corroboration of said model (Paul 2002, Prum & Brush 2002, 2003).

Data can, and has, been produced to falsify the simplistic if cherished notion of feathers being “scales gone frayed,” and consequently this postulate is no longer at the forefront of research into the origin of feathers, and has not been seriously advanced since Regal’s study in 1975. The developmental model is also interesting in that it falsifies the objections that feathery integument should not be observed in theropods requiring a thermoregulatory coat, by demonstrating that the earliest derivatives of feathers would have been quite capable of insulatory function. Perhaps even more pertinent, is the ability of the developmental model to substantiate arguments that the integumentary structures of some of the most paravian maniraptorans are congruent with the pattern, which should be observed in neoflightless post-urvogels (Paul 2002).
Contrary to the assertions made by Sarfati in the AIG interview, there is no data to suggest that exaptation is not a viable explanation for the development of flight feathers.

Continuation presented in next post.


Vindex Urvogel

Continuation of prior post:


4. The Phylogenetic Placement of Mononykus olecranus, Protarchaeopteryx robusta, and Caudipteryx zhoui.

Two principal claims are advanced regarding these taxa, which are subsequently reiterated by Sarfati in the AIG interview: that Mononykus is irrelevant to avian phylogeny and by default unrelated to birds, and that both Protarchaeopteryx and Caudipteryx are neoflightless avialians.

The phylogenetic status of Mononykus and its containing clade, Alvarezsauria remain contentious, although the osteology of these specimens is entirely unambiguous in its testimony as to the affinities thereof. Initial work by Perle et al (1993), Ostrom (1994), Wellnhofer (1994), Kurochkin (1995), Zhou (1995), Feduccia (1996) and Martin (1997) in which the presence of avian synapomorphies were discounted in Alvarezsauria are no longer congruent with subsequent material attributed to this clade. The most recent phylogenetic analyses of the alvarezsaur material (Karhu & Rautian 1996, Chiappe et al 1996, 1998, Novas 1997, Padian & Chiappe 1998, Longrich 2000, Paul 2002) have demonstrated the presence of multiple characters synapomorphic of Avialae, particularly in the temporal region of the skull and the suspensorium.

The suspensorium has been modified to permit streptostylic kinesis, and the orbits are confluent with the ventral aspect of the post-temporal fenestra, as the postorbital bar is incomplete medially. The jugal and quadratojugal are fused into a jugal bar, and the articulation with the quadrate is highly kinetic. The proximal condyle of the quadrate is doubled, and articulates with the braincase, and the mobility of the quadrate is furthered by the lack of descending process of the squamosal. Lastly, the ectopterygoid is absent (Chiappe et al 1996, 1998, Padian & Chiappe 1998, Paul 2002). These are post-urvogel traits and demonstrate that as regards cranial kinesis, alvarezsaurs were more derived than Archaeopteryx lithographica, Confuciusornithidae, and other archaic Pygostylia. These data are irreconcilable with the argument that alvarezsaurs are wholly unrelated to Avialae.

Further characters synapomorphic of Avialae and Alvarezsauria are found in the pelvic girdle and the femur, which especially at the proximal extremity is astonishingly avian. A robust antitrochanter is present on the acetabular wall and the pubic symphysis is limited to the distal portion of the pubes. The femora display confluence of the lesser and greater trochanters and both a lateral and cranial cnemial crest are present (Chiappe et al 1996, 1998, Padian & Chiappe 1998, Paul 2002).

Arguments for the ornithomimosaur affinity of Alvarezsauria (Martin 1997, Sereno 1999) overlook detailed synapomorphies with Avialae observed in these animals, and instead focus on superficial resemblances to Ornithomimosauria. In particular, the argument that an arctometatarsalian pes allies Alvarezsauria to Ornithomimosauria (Martin 1997, Sereno 1999), is weakened by the homoplastic nature of the pinched central metatarsal, with which Holtz unified Arctometatarsalia (Holtz 1994).

The osteological data at hand strongly suggests that Alvarezsauria are allied with Avialae, although the exact relationship of these taxa is as of yet, indeterminate. Thus, the most substantiated conclusion is to regard Alvarezsauria as Coelurosauria incertae sedis, although Chiappe’s arguments for outgroup status to Metornithes are more than plausible (Chiappe 1995, Chiappe et al 1996, 1998, Padian & Chiappe 1998). Thus, Sarfati’s comments to the extent that consensus had been reached whereby the paleontologic community has agreed the Alvarezsauria are irrelevant to avian phylogeny, are falsified.

The claims that Protarchaeopteryx and Caudipteryx are neoflightless Aves, and not members of Coelurosauria rest on one character, and one character alone: the presence of what are undeniably feathers in these taxa (Feduccia 1996, 1999, 2002). The arguments raised in protest to this phylogenetic semantics are not to be construed as disputing neoflightless status of these taxa (which is almost certain), but rather to reiterate that the osteology of the respective genera displays characters synapomorphic of Theropoda, and thus their status as theropods is well substantiated.

While the Protarchaeopteryx material is not particularly well preserved, what material is available displays the same catalogue of synapomorphies seen in its closest relative, the urvogel, that ally both with Deinonychosauria. Similarly, the lack of autapomorphic characters of Avialae strongly refutes the suggestion that in Protarchaeopteryx, we are seeing a neoflightless bird, as opposed to a neoflightless dinosaur. Most telling is the structure of the braincase and temporal region of the skull, which appear congruent with that of Archaeopteryx (Paul 2002).

Proponents of “thecodont” ancestry have vociferously argued that Caudipteryx zhoui is a neoflightless avialian most closely allied to Confuciusornithidae (Martin in Gibbons 1999, Feduccia 1999, Feduccia in Fischman 1999, Martin & Czerkas 2000, Ruben & Jones 2000). However, at every turn these conclusions are shown untenable by the material available. First and foremost, since the most recent attack on the dinosaurian affinity of Caudipteryx (Ruben & Jones 2000), new material attributable to the species has been recovered and described (Zhou & Wang 2000, Zhou et al 2000), which has concomitantly led to a more thorough understanding of caudipterygian osteology.

Caudipteryx displays multiple characters synapomorphic of Oviraptorosauria. Contrary to Feduccia’s assertions, said traits are not limited to the articulation of the temporal region. In the analyses offered by Sereno (1999), Zhou & Wang (2000), Zhou et al (2000), and Barsbold et al (2000), only the contact of the quadrate and quadratojugal are stressed as plesiomorphic comparative to Avialae, as regards cranial characters. Traits allying caudipterygians and oviraptorosaurs in a holophyletic clade (sensu Sereno 1999, Barsbold et al 2000) include the structure of the pubes, the procumbent orientation thereof, the prominent obturator process, the shallow pelvic canal, the contact between the fibula and calcaneum, and the dorsolateral projections of the astragalus, which overlap the calcaneum (Sereno 1999, Barsbold et al 2000). The structure of the mandibles seems to further ally these two groups (Paul 2002), but until such time as crania preserved with greater fidelity are recovered, definitive statements in this regard cannot be made.

The argument posed by Feduccia (1999) and repeated by Sarfati, that herbivory in caudipterygians is irrefutable evidence for avialian status, is directly falsified by the herbivorous or at least omnivorous paleobiology of oviraptorosaurs, and particularly therizinosaurs—both theropod clades. In light of the osteology unifying caudipterygians and oviraptorosaurs, arguments that Caudipteryx is merely a neoflightless avialian, are at best unsubstantiated, and at worst entirely specious.


5. General Body Proportion in Theropoda

Perhaps the most erroneous claim presented by proponents of “thecodont” ancestry, and repeated by Sarfati, is that the theropod bauplan is proportionally at odds with that observed in Avialae, thus precluding the theropod derivation of birds (Feduccia 1999, Geist & Feduccia 2000, Tarsitano et al 2000). The assertion to this effect primarily centers on the allegedly short arms of theropods, which would preclude their exaptation into airfoils, ergo, wings. Patently absurd in light of the fossils of Theropoda, this argument has nonetheless persisted amongst opponents of the theropod ancestry of birds.

Ornithomimosauria, particularly Deinocheirus mirificatus, and taxa allied thereto, display arms which approached 2.4 meters in overall length (which yields a radius more than 50% of the forelimb length), and are proportionally among the longest of dinosaur arms (Osmolska & Roniewicz 1970, Dodson et al 1990, Paul 2002). Oviraptorosaurs, in addition, display proportionally large forelimbs (see esp. Avimimus portentosus, Kurzanov 1981, Fig. 13.5 in Dodson et al 1990).

Yet the most spectacular refutation of the proportional arguments comes from the deinonychosaur material recovered in the last three years, which indicates that basal dromaeosaurs possessed forelimbs which reached as much 80% the length of the hind-limb (Xu, Tang & Wang 1999, Burnham et al 2000, Paul 2002). These data taken as a whole suggest a pattern of forelimb elongation amongst some maniraptoran clades over time, precisely the ontogenetic pattern to be expected if said taxa were increasingly paravian in their osteology.

The concomitant argument presented by Sarfati, that theropod hind-limbs were too muscular to permit their being allied to Avialae is curious in that it has no apparent relevance to avian phylogeny in the first place. Moreover, it is incorrect. The caudal and forelimb musculature of basal dromaeosaurs and troodonts is rather weakly developed comparative to more derived Deinonychosauria (e.g., Deinonychus antirrhopus), and indeed such reduction of the caudal and forelimb musculature is congruent with arboreal habitat (Paul 1988, 2002).


7. Patterns of Temporal Distribution

A central tenet of the “thecodont” ancestry of birds, repeated in the AIG interview by Sarfati, is that there is an intractable chronological discontinuity between Maniraptora and Avialae. Considering that no member of Deinonychosauria is advanced as the phyletic progenitor of Avialae, this argument has always been peculiar in that it distorts the position of those advocating theropod origin.

The temporal distribution of Maniraptoriformes, extending to the Upper Jurassic (Padian & Jensen 1989, Dodson et al 1990, Dingus & Rowe 1998), and possibly to the Lower Triassic (Zhao & Xu 1998, Paul 2002) is congruent with the consensus that Avialae represents the sister clade of Deinonychosauria, with said taxa splitting in the Upper Jurassic and pursuing independent evolutionary trajectories. No data has been presented with which to falsify a sister-clade relationship on temporal grounds.

Moreover, if the most par-avian of Maniraptora are neoflightless post-urvogels, temporal disparity is ever more so reduced to a non-issue, in that the alleged stratigraphic gap between Avialae and Maniraptora would be precisely expected by the phylogeny at work. Considering the steadily mounting data to support this hypothesis, such a resolution of the ostensible temporal paradox so cherished by advocates of “thecodont” ancestry, cannot be readily dismissed. Summations of such data can be found in: Osmolska (1976), Kurzanov (1981, 1982, 1985, 1987), Paul (1984), Molnar (1985), Perle et al (1983, 1984), Paul (1988), Olshevsky (1994), Elzanowski (1995, 1999), Sereno (1997), Chatterjee (1999) and Paul (2002).

Considering the data at hand, Sarfati’s comments on the temporal distribution of Maniraptora and Avialae are not tenable.


Vindex Urvogel

8. A Modern Bird, not a Dinosaur

The ostensible lack of dinosaurian affinities is a simply astounding assertion in light of the osteology. Archaeopteryx retains its prominent axial epipophyses, caudually bowed ulna, a semilunate carpal block, strongly twisted paroccipital process, diamond shaped dorsal supraocciptital, a pneumatopore on the paroccipital, doral fossa on the ectopterygoid process, vaulted palatines, pinched nasals, accessory maxillary fenestrae leading to the auxiliary maxillary sinuses, tuber rostrodorsal to the antorbital fenestra, an infratemporal fenestra reduced to a foramen, auxiliary process of the caudodoral surface of the ischia, theropod eggshell structure, articulation of the hallux to the posterolateral aspect of the shaft on metatarsal II, its positioning posterior to metatarsals II-IV, the sacral vertebrae count (probably six), etc. These characters not only place Archaeopteryx within Dinosauria, but unite Eumaniraptora as holophyletic.

What is equally astounding is Sarfati’s claim that Archaeopteryx is little more than a “modern perching bird.” The terrible irony, of course, is that Archaeopteryx is amazingly plesiomorphic with regard to Avialae and the more derived birds seen in Ornithurae. For example, the two cnemial crests, an orbital process of the quadrate, the pateller groove on the femur, pygostyle, pneumatic fossa of the proximal humerus, sternal ribs, uncinate processes, ulnar quill knobs, distal tendinal pit of the ulna, pygostyle, heterocoelus centra, carpometacarpus, rhamphotheca, tarsometatarsus, hypertrophied bicipital crests, ventrally oriented occipital condyle and foramen magnum (among other characters), are all suspiciously absent.

So what are the characters that actually warrant classifying Archaeopteryx as avialan? Unfortunately for Dr. Sarfati, the list is brief. The holophyly of Archaeopterygiformes is underwritten by precisely seven characters: small teeth, a conical, sternal breadth/length ratio 3.5/4, sternum with a narrow anteromedial indentation, slender fingers, an ilium with posterior process, a deep pelvic canal, and metatarsal, tarsals and carpals unfused but tightly articulated. All those characters typically regarded as apomorphic of birds (like feathers or the mere presence of furculae) are now known throughout Theropoda (feathers, only in Maniraptoriformes).

In summation, we can see that Dr. Sarfati has once again presented his audience with an erroneous interpretation of the facts. His blanket assertions as to the taxonomic status of Archaeopteryx, when closely examined, fail to stand up. It is as wonderful a transitional form as ever.

9. The Theropod Debate

Sarfati repeatedly implied throughout the interview that there is considerable disagreement about theropod origins in the paleontological community. Nothing could be further from the truth. The principal detractors, limited to Olson, Feduccia, Martin, Ruben, Tarsitano, Hecht, Ellenberger, and two or three others, is pitted against nearly all of paleontology:

Gingerich (1973), Galton & Bakker (1976), Osmolska (1976), Kurzanov (1981, 1982, 1983, 1985, 1987), Barsbold (1983), Thulborn (1984, 1985), Currie (1985, 1987), Molnar (1985), Ostrom (1985, 1990, 1991, 1994, 1995), Raath (1985), Wellnhofer (1985, 1988, 1993, 1994), Bakker (1986), Weems (1987), Carroll (1988), Paul (1988), Chatterjee (1991, 1995, 1997, 1998, 1999), Novas (1991, 1997), Rayner (1991), Ezanowksi & Wellnhofer (1992, 1993, 1996), Sanz & Bonaparte (1992), Sereno & Rao (1992), Currie & Zhao (1993), Russell & Dong (1993), Olshevsky (1994), Perle et al (1994), Chiappe (1995), Chiappe et al (1996, 1997, 1998), Ji & Ji (1996, 1997), Karhu & Rautian (1996), Horner & Dobb (1997), Larson (1997), Norell & Makovicky (1997, 1999), Noavas & Puerta (1997), Britt et al (1998), Dingus & Rowe (1998), Forster et al (1998), Griffiths (1998/2000), Gower & Weber (1998), Holtz (1998/2000), Ji et al (1998), Padian & Chiappe (1998), Garner et al (1999), Schweitzer et al (1999), Sereno (1999), Wagner & Gauthier (1999), Barsbold et al (2000), Brochu & Norell (2000), Burnham et al (2000), Christiansen & Bonde (2000), Farlow et al (2000), Gould (2000), Martill et al (2000), Rensberger & Watabe (2000), Sumida & Brochu (2000), Xu et al (2000, 2001), Zhou & Wang (2000), Zhou et al (2000), Hutchinson (2001), Ji et al (2001), Norell et al (2001), etc.

10. Archaeoraptor

While Sarfati is technically correct about Archaeoraptor being chimerical (not a “hoax” or a “fraud”, as Sarfati painted it), is should be noted that the paleontological community exercised a great deal of caution and never hailed it as the sine qua non proof of theropod origins. Outside of the pages of National Geographic (for which they should be appropriately embarrassed) nothing of the sort was done.

A reply to the charge of a lack of digital homology will be forthcoming.

-GFA

Today @ 01:21 AM post located here
_GFA_:

In summation, we can see that Dr. Sarfati has once again presented his audience with an erroneous interpretation of the facts.

JM: Excellent summary of why a former chemist should stick to topics he knows something about. Sarfati's constant whinging about real scientific evidence shows the state of desperation in young earth creationism. They have failed to provide evidence for a young earth, a global flood and special creation. They don't have much left.

Cheers

Joe Meert

Moderated By: Undisclosed

I am leaving everything intact, but I remind everyone that back to back huge posts are not allowed. We have a 24K post limit for a reason. I am asking the original poster to know distill those two large posts down to one to two points for discussion. Thanks. ***If you wish to take issue with this notice DO NOT do so in this thread.*** Contact the forum moderator or an administrator in Private Message or email instead. If you feel you must publically complain or whine, please take it to the Psychotherapy Room unless told otherwise.

Moderated By: Undisclosed

In the future these long back to back posts will be edited and saved for the writer. I cut VU some slack since he was a brand new member... however, I am asking that it be distilled to a few points for discussion before moving on. ***If you wish to take issue with this notice DO NOT do so in this thread.*** Contact the forum moderator or an administrator in Private Message or email instead. If you feel you must publically complain or whine, please take it to the Psychotherapy Room unless told otherwise.

Urvogel and I would appreciate a response to any of the aforementioned points of the oppositions choosing. However, the deafening silence the past couples days smells an awful like a tacit concession to me. Surely we haven't converted all of TWeb over to theropod origins!

-GFA

Actually GFA, it really doesn't work that way. I let the posts remain to cut new guys some slack, but it is not up to participants to initiate conversations by picking and choosing points from a thick article. I ask once again that you or U. choose a few points and initiate discussion.

Exactly. Silence is never consent. Not many of us have the time to sift through a huge pile of crap to find a tomato seed. If you want to address one point, make it ... and if we have the time, we will answer.

Not many of us have the time to sift through a huge pile of crap to find a tomato seed

So which parts were "crap" Sher? Surely as a moderator you're aware of the policy of being able to support such banal invectives?

Today @ 09:04 PM post located here
blackthorne:

So which parts were "crap" Sher? Surely as a moderator you're aware of the policy of being able to support such banal invectives?

Okay ... I withdraw the crap comment for the whingers

So which parts were "crap" Sher?

Moderated By: Undisclosed

You two please take it to the Locker Room. I am closing this thread until either GFA or VU Private Message or email me that they are ready to distill down to a few points for discussion. ***If you wish to take issue with this notice DO NOT do so in this thread.*** Contact the forum moderator or an administrator in Private Message or email instead. If you feel you must publically complain or whine, please take it to the Psychotherapy Room unless told otherwise.

Moderated By: Undisclosed

GFA has opened several new threads narrowing down the issues. Discussion can take place there. Note for the future. I cut the two new guys some slack in letting their posts stay. They should have been deleted. ***If you wish to take issue with this notice DO NOT do so in this thread.*** Contact the forum moderator or an administrator in Private Message or email instead. If you feel you must publically complain or whine, please take it to the Psychotherapy Room unless told otherwise.