Wednesday, April 28, 2010

Pickering's taxa 5: Elaphrosaurus philtippettensis

I took a break from "Liassaurus" to get this quickie out of the way.

Tanycolageus Carpenter, Miles and Cloward, 2005
T. topwilsoni Carpenter, Miles and Cloward, 2005
= Elaphrosaurus "philtippettensis" Pickering, 1995b
= Elaphrosaurus "philtippettorum" Pickering, 1995a
Late Kimmeridgian, Late Jurassic
Brushy Basin Member of the Morrison Formation, Colorado, US
Paratype- ?(USNM 5737; intended holotype of Elaphrosaurus "philtippettensis" and "philtippettorum") distal pubes (Gilmore, 1920)
 
Comments- The distal pubes USNM 5737 were discovered in 1884 and provisionally referred to Coelurus agilis by Gilmore in 1920 based on their size. Pickering (1995a) listed the name Elaphrosaurus philtippettorum in an unpublished bibliographic manuscript. In that same year, Pickering printed a packet with a description of the taxon as ?Elaphrosaurus philtippettensis, indicating USNM 5737 is the intended type. Both variants on the name are nomina nuda however, as he didn't follow ICZN Article 8.1.3- it must have been produced in an edition containing simultaneously obtainable copies by a method that assures numerous identical and durable copies. Pickering also referred USNM 8414 (two metatarsals) and 8415 (a humerus) without justification. However, there are no characters in the diagnosis except that it shares a straight humerus with Elaphrosaurus and abelisaurids (which does not involve the intended type), and the only characters listed in the description are those which distinguish USNM 8415 from Dryosaurus (identical to those listed by Galton in 1982). It is therefore also a nomen nudum in that it lacks "a description or definition that states in words characters that are purported to differentiate the taxon." Oddly, the intended type is not illustrated, with the only illustration being a humeral figure from Galton's paper.  Pickering will also describe the species in his in progress work Mutanda Dinosaurologica. Carpenter et al. (2005) referred USNM 5737 to their new taxon Tanycolagreus because of its straight ventral edge and dorsally placed interpubic fenestra, unlike Coelurus. Additionally, Ornitholestes lacks an interpubic fenestra altogether. Why Pickering referred USNM 5737 to Elaphrosaurus is unknown, as he does not discuss the specimen (except to note it is "elongate, ... lacking a crest on its craniodorsal surface. In lateral view, the distal foot is ventrally convex.") and E. bambergi does not preserve the distal pubis. Furthermore, other ceratosaurs like Ceratosaurus, Kryptops and Carnotaurus have a very distally placed interpubic fenestra, so USNM 5737 is probably not a ceratosaur. Carpenter et al.'s assignment is here retained, though it should be noted Stokesosaurus also has a distally flat pubic boot and proximally placed interpubic fenestra.
 
unnamed Ceratosauria (Galton, 1982)
Late Kimmeridgian, Late Jurassic
Brushy Basin Member of the Morrison Formation, Colorado, US
Material- ?(USNM 8414) metatarsal III, metatarsal IV (Pickering, 1995)
(USNM 8415) humerus (201 mm) (Galton, 1982)

Comments- The humerus USNM 8415 was discovered in 1883 and initially referred to Dryosaurus, though Galton (1982) described it and referred it to Elaphrosaurus sp. based on the straight shaft and low deltopectoral crest. Pickering (1995b) referred it to his new taxon ?Elaphrosaurus "philtippettensis" without justification. Neither listed any characters to differentiate it from E. bambergi. Carrano and Sampson (2008) thought the specimen was ceratosaurian, but could find no characters shared specifically with Elaphrosaurus. Indeed, the straight shaft is present in all ceratosaurs, while the low deltopectoral crest is present in Limusaurus and abelisaurians as well. The proximal articular surface is wider than Limusaurus, but less so than abelisaurians. The flattened distal condyles are also more derived than Limusaurus, while Spinostropheus is intermediate. The internal tuberosity is well developed as in Ceratosaurus and abelisaurids, but unlike Limusaurus, Elaphrosaurus, Spinostropheus and Masiakasaurus. The deltopectoral crest apex is placed more distally (42%) than Elaphrosaurus, Limusaurus and especially Ceratosaurus and Masiakasaurus, but is more proximal than abelisaurids. Based on these comparisons, I agree the humerus cannot be assigned to Elaphrosaurus.


Ceratosaur humerus USNM 8415 in anterior (A), medial (B), posterior (C), lateral (D), proximal (E) and distal (F) views (after Galton, 1982).  Scale = 50 mm.

USNM 8414 was discovered in 1883 and is assigned to Elaphrosaurus sp. on the USNM collections website, though it has not been mentioned in the literature to my knowledge. Pickering (1995b) referred it to his species Elaphrosaurus "philtippettensis" without comment. Until these are illustrated or described, their affinities remain unknown.

References- Gilmore, 1920. Osteology of the carnivorous Dinosauria in the United States National Museum, with special reference to the genera Antrodemus (Allosaurus) and Ceratosaurus. Bulletin of the United States National Museum. 110, 1-154.

Galton, 1982. Elaphrosaurus, an ornithomimid dinosaur from the Upper Jurassic of North America and Africa. Paläontologische Zeitschrift. 56, 265-275.

Pickering, 1995a. Jurassic Park: Unauthorized Jewish Fractals in Philopatry. A Fractal Scaling in Dinosaurology Project, 2nd revised printing. Capitola, California. 478 pp.

Pickering, 1995b. An extract from: Archosauromorpha: Cladistics and osteologies. A Fractal Scaling in Dinosaurology Project. 2 pp.

Carpenter, Miles and Cloward, 2005. New small theropod from the Upper Jurassic Morrison Formation of Wyoming. In Carpenter (ed.). The Carnivorous Dinosaurs. Indiana University Press. 23-48.

Carrano and Sampson, 2008. The phylogeny of Ceratosauria (Dinosauria: Theropoda). Journal of Systematic Palaeontology. 6, 183-236.

Friday, April 23, 2010

Pickering's papers in hand- A review

Continuing Pickering Month, I thought I'd take a break from the "Liassaurus" entry to write a different kind of post.  Stephan sent me copies of several of his papers this week, which means I'm one of a handful of people to own them.  Many of you are probably wondering just what does a Pickering paper look like?  Well now's your chance to find out.  I'd also like to thank Stephan for (finally) sending me the papers, as it took quite a bit of time on his part.  So, the papers I received can be divided into a few categories.

One is an in progress version (from 2003) of his bibliography of Richard Owen, with illustrations by Knight and Stout.  Simple enough.

Another is a flier for Mutanda Dinosaurologica, Pickering's in progress book.  This lists the species covered in the book, which consists of all the standard Pickering theropods, as well as Liliensternus, Sarcosaurus, Elaphrosaurus, Magnosaurus as Megalosaurus nethercombensis, Megalosaurus bucklandii, Eustreptospondylus, Metriacanthosaurus parkeri, Streptospondylus, Poekilopleuron and Proceratosaurus.  Presumably these were the taxa redescribed by Welles and Powell for their European theropod review which was never published, and I assume that the Extract from Archosauromorpha papers described below are basically the kind of content that will be included (albeit with possible revisions) if Pickering ever publishes.


Cover of volume about Dilophosaurus "breedorum."

Six are titled "An Extract from: Archosauromorpha: Cladistics and Osteologies".  Two such papers were mentioned by Olshevsky on the DML, about Dilophosaurus "breedorum" and Megalosaurus bucklandii.  Pickering has not sent me the latter yet.  The others I received are- "Merosaurus", Elaphrosaurus? "philtippettensis", "Altispinax" "lydekkerhueneorum", "Walkersaurus" and Maleevosaurus.  Two (about Maleevosaurus and "Altispinax") are stated to be volume 14, the others lack numbers.  They all begin with photocopied copyright certificates, though of course no one doubts much of the material was written by Welles and Powell in 1974, 1993, etc..  The problem is that the ICZN doesn't care about copyright, but rather whether it's "produced in an edition containing simultaneously obtainable copies by a method that assures numerous identical and durable copies."  The content itself is basically what you see from Pickering in his comments here- basic info, lists of previous references to the specimen in the literature, generally problematic diagnoses, then a very Welles-ian description.  You'll recognize the format if you've read Welles' 1984 Dilophosaurus osteology- descriptions of each element focusing on measurements of landmarks, followed by comparisons to similar taxa but without any phylogenetic context.  The Maleevosaurus paper breaks the mold a bit in that it has an extensive set of measurement tables instead of a description.  There are quite a few original photos taken by Welles in 1974 I presume, and original illustrations of Dilophosaurus and the "Merosaurus" type femur.  The other line drawings are taken from previously published sources.  One common issue I have with these taxa is several are based on non-overlapping elements with no justification for their referral.  I've already noted this for "Merosaurus" for instance, but the Altispinax paper is a particularily egregious example.  The proposed lectotype is the Becklespinax holotype of three high-spined dorsals.  Yet referred specimens include teeth, metatcarpals, metatarsals (such as the Valdoraptor holotype), pedal phalanges, etc..  Pickering doesn't identify the taxon past Tetanurae, so can't even use a rationale like Benson's that the large Taynton Limestone theropod material is all megalosaurid or compatible with such an identification.  Similar issues are seeimingly true for "brevis", "reynoldsi" and "philtippettensis".


Page 12 of King Kong: Unauthorized Jewish Fractals in Philopatry, including section naming Allosaurus "whitei" and Tyrannosaurus "stanwinstonorum."

The final object is a pamphlet that I believe was distributed with an issue of Prehistoric Times in 1996, which gives it the highest and most official distribution of any Pickering work.  This is the famous "King Kong: Unauthorized Jewish Fractals in Philopatry. A Fractal Scaling in Dinosaurology Project."  It's thirteen pages long, and is quite Pickering-esque if I do say so.  The first four pages are confusingly labeled as advertisements, though they don't differ qualitatively from the rest.  Large pictures relating to Jurassic Park 2: The Lost World and King Kong are strewn throughout, and the text is divided into nine chapters, a prologue (between chapters 6 and 7), a postscript and an epilogue.  The first six chapters are commentary on The Lost World, while the prologue and chapters 7-9 are commentary on King Kong.  They are not scientific writings by any means, though they would be fine (if verbose) articles in a theater magazine.  The postscript is partly a speculation of dinosaur mating habits based on birds, which is flawed by the large (almost total) amount of speculation and the author's well known habit of calling all birds dinosaurs.  So we get "spotted sandpiper dinosaurs" and "Scandinavian pied-flycatcher-dinosaurs."  Not that this is inaccurate, it's simply tedious and redundant, much as African elephant mammals and alligator snapping-turtle-reptiles would be.  There's another paragraph about such varied topics as ceratopsian limb posture and sauropod metabolism, but the interesting portion of the postscript is that titled Freud's Door (though it is not about Freud at all).  By way of a criticism of certain phylogenetic practices, Pickering lists "the superspecies of Tyrannosaurus" including T. [rex] bataar, T. [rex] rex, and T. [rex] stanwinstonorum followed by diagnoses for each.  I'm really not sure what a superspecies is, nor what his bracketed notation indicates, but in any case the diagnosis for "stanwinstonorum" is based on characters which are probably individual variation (larger body size than T. rex; reduced nasal rugosities), incorrect (palatine recess absent; rugosity absent on ventral pterygoid wing of palatine; supradentary absent), or ambiguous (reduced postorbital-orbital joint). Pickering also mentions Allosaurus and provides a diagnosis of A. "whitei", which as Chure (2000) notes in detail is invalid for the same reason Paul's version of A. atrox and Bakker's version of Creosaurus are.  Finally, the Epilogue consists of a taxonomic criticism, leading the reader to his erection of a new species of Ceratosaurus- C. "willisobrienorum."  It turns out this is based on both the holotype of C. magnicornis (the proposed type of Pickering's species) AND C. dentisulcatus.  I have no opinion on the taxonomy of Ceratosaurus at the moment, as I have not studied the issue.  This is directly followed by a more opaque concluding paragraph which has been partially quoted by Chure in his thesis ("Multiple levels of ebbulient perception inundate one's post-Obie existence, as the epochal significance of King Kong is to be firmly positioned in the imagi-nation..."), involving theater, Judaism and the like.

My final judgement is a mixed bag.  The osteologies contain much useful information, though I prefer Benson's descriptive method, explanatory line drawings and phylogenetic context.  Of course Welles wrote much of it in the 70's and 80's, so the lack of much phylogenetic context isn't surprising.  The taxonomic and specimen referrals are often undefended and problematic, which is another downfall.  Much of "King Kong: Unauthorized Jewish Fractals in Philopatry" isn't as bad as it's been made out to be- for a pair of movie commentaries.  It's usually readable, if that sort of thing interests you.  But it's not anything you'd find in a technical journal, and the dinosaur sections lack a common theme.  They might be appropriate for Prehistoric Times, though I think there's too much speculation and too little evidence to back it up.  Pickering's idiosyncratic terminology for birds also elicits eye rolls after a while.  The new names proposed in this paper seem like afterthoughts.  They merit a name, material list and a diagnosis, and then it's on to the next topic.  Even ignoring the ICZN, that's no way to propose a new taxon.

Next up, "Liassaurus", then probably a couple more taxa to round out the month.

Saturday, April 17, 2010

Pickering's taxa 4: Merosaurus newmani

Owen received the partial hindlimbs BMNH 39496 and GSM 109560 in 1858 and used them as the basis for his dinosaur genus Scelidosaurus in an encyclopedia entry the following year. While this is often claimed to be an nomen nudum (e.g. Newman, 1968), genus names published before 1931 do not require species names or illustrations to be valid (ICZN Article 12). Owen later (1861) gave his taxon the species name harrisonii and described it in detail, referring the ungual GSM 109561, a partial postcranium in the Lyme Regis Museum, and the skull of BMNH R1111. Lydekker (1888) made BMNH 39496 the type specimen, though the basal thyreophoran BMNH R1111 (whose postcranium was soon found and described in 1862) formed the basis for peoples' ideas of Scelidosaurus. Newman (1968) believed BMNH 39496 and GSM 109560 to be megalosaurids, and possibly GSM 109561 as well. However, they were only compared to Megalosaurus among theropods, making this familial assignment in need of verification. As the name Scelidosaurus had been associated with the thyreophoran, Charig and Newman (1994) petitioned the ICZN to recognize BMNH R1111 as the lectotype, which was accepted in 1994 as Opinion 1788. Pickering (1995) credited the name Merosaurus newmani to Welles, Powell and Pickering in an unpublished bibliographic manuscript. This is a nomen nudum however, as he didn't follow ICZN Article 8.1.3- it must have been produced in an edition containing simultaneously obtainable copies by a method that assures numerous identical and durable copies. The name may date from the English megalosaur redescription of Welles and Powell from the 1970's which was never published. Olshevsky (DML, 1999) believed "Merosaurus" referred to BMNH 29496, and statements by Pickering on a private newsgroup in 2005 confirmed it is based on this specimen and GSM 109560. He referred to BMNH 39496 as the type, comparing it favorably to Sarcosaurus, Dilophosaurus and Ceratosaurus in morphology. Pickering will presumably describe it in his in progress work Mutanda Dinosaurologica. Carrano and Sampson (2004) stated BMNH 29496 probably belongs to a basal tetanurine without explanation, but viewed it as indeterminate. Naish and Martill (2007) referred all three specimens to Tetanurae without comment. Most recently, Benson (2009, 2010) redescribed BMNH 39496 and GSM 109560. He found BMNH 39496 to be a coelophysoid when entered in his matrix, but noted that non-tetanurines were poorly sampled so this may not mean much. Benson considered it to be Theropoda incertae sedis, and the other two specimens to be indeterminate theropods.


Intended "Merosaurus" holotype BMNH 39496.  Femur in A/B anterior, C medial, D/E posterior, F lateral and L distal views (after Benson, 2010). Tibia in G anterior, H medial, I posterior, J/K lateral and M proximal views (after Benson, 2010). Fibula in O lateral, P posterior and tibia and fibula in N distal views (modified from Owen, 1861). Scale = 100 mm.

“Merosaurus” Welles, Powell and Pickering vide Pickering, 1995
“M. newmani” Welles, Powell and Pickering vide Pickering, 1995
Hettangian-EarlySinemurian, Early Jurassic
Blue Lias Formation, England
Material- (BMNH 39496; holotype of Scelidosaurus harrisonii) distal femur (~640 mm), proximal tibia, proximal fibula (lost)
Diagnosis- (suggested) combination of bulbous fibular crest on tibia and very shallow extensor groove on distal femur.

Comments- BMNH 39496 consists of a distal femur, proximal tibia and a proximal fibula which has been lost subsequent to Newman's description. Both Pickering and Benson proposed the lack of a deep extensor groove as a non-tetanurine character, but this is true in some basal tetanurines (Chuandongocoelurus), megalosauroids (Dubreuillosaurus, Eustreptospondylus, "Brontoraptor") and most coelurosaurs. Contra Pickering, the popliteal notch is concave and the ectocondyle elliptical and posterolaterally directed even in tetanurines like Megalosaurus and Eustreptospondylus. Benson claims the fibular crest which extends to the lateral condyle is a non-tetanurine character, but this is also found in Afrovenator, Megalosaurus and Gasosaurus. One feature of the tibia might suggest this specimen is a tetanurine- the fibular crest is bulbous as in Piatnitzkysaurus, Megalosaurus and Sinraptor. However, including BMNH 39496 in my saurischian supermatrix results in equally parsimonious trees where it is in Coelophysoidea or non-avetheropod Tetanurae. Morphologies in the preserved areas are not consistantly variable between these groups, making further identification difficult. Thus it is here assigned to Avepoda incertae sedis.


Ceratosaur femur GSM 109560 in N/O medial, P/Q anterior, R posterior and S lateral views (after Benson, 2010). Scale = 100 mm.

Ceratosauria indet. (Owen, 1861)
Hettangian-EarlySinemurian, Early Jurassic
Blue Lias Formation, England
Material- (GSM 109560) partial femur (~380 mm), partial tibia (lost)

Comments- GSM 109560 is based on a femur lacking the head and distal end, and a tibial shaft which was not illustrated by Owen and has been lost. Contra Owen and Pickering, there is no reason to refer this to the same taxon as BMNH 39496 as they share only a short area of distal shaft, and the GSM specimen is only ~60% as large. Also contra Pickering, the anterior trochanter is not conical but is lateromedially narrower than anteroposteriorly, making it alariform. The specimen is not a robust coelophysoid or ceratosaur individual based on the absence of a ridge-like trochanteric shelf. It is most similar to Liliensternus, Dilophosaurus, Ceratosaurus and tetanurines in having a straight shaft in anterior view. The anteroposterior width of the anterior trochanter seems less than in tetanurines, but greater than basal coelophysoids. It may be a gracile morph of ceratosaur.

Massopod pedal ungual GSM 109561 in A dorsal, B lateral(?) and C proximal views (after Owen, 1861).

Massopoda indet. (Owen, 1861)
Hettangian-EarlySinemurian, Early Jurassic
Blue Lias Formation, England
Material- (GSM 109561) pedal ungual (74.5 mm)

Comments- The ungual GSM 109561 was not associated with BMNH 39496 or GSM 109560 and was not necessarily assigned to "Merosaurus" by Pickering. Newman stated it was "possibly the terminal phalange of the first digit of a megalosaurian", while Benson believed it to be an indeterminate theropod. However, compared to basal theropod pedal unguals, GSM 109561 is much straighter, stouter, broader and lacks the dorsal overhang on its proximal surface. A closer resemblence is seen to pedal unguals of basal massopods like Blikanasaurus and Jingshanosaurus. It is here provisionally referred to that clade.

References- Owen, 1859. Palaeontology. Encyclopaedia Britannica, Edition 8. 17, 91-176.

Owen, 1861. Monograph of the fossil Reptilia of the Liassic formations. Part I. A monograph of the fossil dinosaur (Scelidosaurus harrisonii Owen) of the Lower Lias. Palaeontolographical Society Monographs. 13, 1-14.

Owen, 1862. Monographs on the British Fossil Reptilia from the Oolitic Formations. Part second, containing Scelidosaurus harrisonii and Pliosaurus grandis. Palaeontolographical Society Monographs. 1-16.

Lydekker, 1888. Catalogue of the Fossil Reptilia and Amphibia in the British Museum (Natural History), Cromwell Road, S.W., Part 1. Containing the Orders Ornithosauria, Crocodilia, Dinosauria, Squamata, Rhynchocephalia, and Proterosauria. British Museum of Natural History, London. 309 pp.

Newman, 1968. The Jurassic dinosaur Scelidosaurus harrisoni Owen. Palaeontology. 11, 40-43.

Charig and Newman, 1992. Scelidosaurus harrisonii Owen, 1861 (Reptilia, Ornithischia): Proposed replacement in inappropriate lectotype. Bulletin of Zoological Nomenclature. 49, 280-283.

ICZN, 1994. Opinion 1788. Scelidosaurus harrisonii Owen, 1861 (Reptilia, Ornithischia): Lectotype replaced. Bulletin of Zoological Nomenclature. 51(3), 288.

Pickering, 1995. Jurassic Park: Unauthorized Jewish Fractals in Philopatry. A Fractal Scaling in Dinosaurology Project, 2nd revised printing. Capitola, California. 478 pp.

Olshevsky, DML 1999. http://dml.cmnh.org/1999Dec/msg00193.html

Carrano and Sampson, 2004. A review of coelophysoids (Dinosauria: Theropoda) from the Early Jurassic of Europe, with comments on the late history of the Coelophysoidea. Neues Jahrbuch fur Geologie und Palaontologie Monatshefte. 2004, 537-558.

Naish and Martill, 2007. Dinosaurs of Great Britain and the role of the Geological Society of London in their discovery: Basal Dinosauria and Saurischia. Journal of the Geological Society. 164, 493-510.

Benson, 2009. The taxonomy, systematics and evolution of the British theropod dinosaur Megalosaurus. PhD thesis. University of Cambridge.

Benson, 2010. The osteology of Magnosaurus nethercombensis (Dinosauria, Theropoda) from the Bajocian (Middle Jurassic) of the United Kingdom and a re-examination of the oldest records of tetanurans. Journal of Systematic Palaeontology. 8(1), 131-146.

Pickering, in prep. Mutanda Dinosaurologica.

Friday, April 9, 2010

Pickering's taxa 3: Metriacanthosaurus reynoldsi

"Metriacanthosaurus" "reynoldsi" Welles, Powell and Pickering vide Pickering, 1995
Early Bathonian, Middle Jurassic
Chipping Norton Limestone Formation, England

Material- ?(BMNH R9679) sacrum
?(BMNH R9680) sacrum
?(GSM 37523) dorsal vertebra
?(OUM J.13720) proximal caudal vertebra
?(OUM J.29799) proximal caudal vertebra
?(SDM 44.7) distal caudal vertebra
?(SDM 44.10) dorsal vertebra
?(SDM 44.16) proximal scapula (Reynolds, 1939)
?(SDM 44.17) proximal scapula (Reynolds, 1939)
(SDM 44.19; intended holotype) ilium (Reynolds, 1939)
?(SDM 44.22) humerus
? tooth (Reynolds, 1939)

Diagnosis- (suggested) several pronounced vertical ridges above the supracetabular shelf extending halfway to the blade's dorsal edge.

Other diagnoses- Pickering (DML, 2002) listed several features as differing from Metriacanthosaurus parkeri. Of these, the straighter dorsal ilial margin and broadly exposed medial wall of the brevis shelf are seen in Eustreptospondylus, while the long ischial peduncle is also present in "Szechuanosaurus" zigongensis. The lower ilial blade are seen in both. Contra Pickering, the pubic peduncle is not noticably longer nor the subpreacetabular notch more open than in Metriacanthosaurus.

Comments- Lydekker (1888) referred a metatarsal III (BMNH R413) from the Chipping Norton Formation to Megalosaurus bucklandi. Gardiner (1937, 1938) and Reynolds (1938) reported large theropod remains from two quarries in the Chipping Norton Limestone Formation, which Reynolds (1939) described and referred to Megalosaurus. Pickering (1995) credited the name Metriacanthosaurus reynoldsi to Welles, Powell and Pickering in his 1995 unpublished bibliographic manuscript. It was later used in the comparative section of another unpublished manuscript (Welles and Pickering, 1999). This paper was largely extracted from the European megalosaur manuscript Welles and Powell worked on in the 1970s but never published, specifically the Megalosaurus redescription section. Pickering intends to publish an updated version of the megalosaur manuscript as Mutanda Dinosaurologica, and has posted small excerpts including the diagnosis of Metriacanthosaurus "reynoldsi" online (DML, 2002). In any case, the name is a nomen nudum as Pickering didn't follow ICZN Article 7 Recommendation 7a, Article 8a or Recommendation 8A. The 1999 paper shows his new taxon to be based on all the Chipping Norton theropod material from both quarries, as well as BMNH R413, scapula OUM J.29800 and a few other elements. Day and Barrett (2004) believed both their Megalosaurus femoral morphotypes A and B were present in the sample- SDM 44.23 (Q in the figure below) as morphotype B and SDM 44.24 as morphotype A. Benson (2009, 2010) referred the New Park Quarry material to Megalosaurus bucklandii based on the close resemblence of maxilla SDM 44.1 (A) to Taynton Limestone specimens and an M. bucklandii autapomorphy in sacrum SDM 44.4 (G), while other elements were provisionally referred as there is no evidence of more than one taxon in the quarry. These additional elements are- maxilla BMNH R8303 (B), anterior dentary BMNH R8304 (D), partial dentary BMNH R8305 (C), proximal ischium BMNH R9668, proximal caudal vertebrae BMNH R9672-9673 (H), partial anterior cervical vertebra BMNH R9674 (E), mid caudal vertebrae BMNH R9675-9676 (J, K?), proximal caudal vertebra BMNH R9677 (I), mid caudal vertebra SDM 44.5 (L), coracoids SDM 44.14-15 (M), humerus SDM 44.18 (N), femur SDM 44.24 (P) and distal metatarsal IV 44.25. BMNH R413 and OUM J.29800 were also referred to M. bucklandii based on autapomorphies. Finally, Benson (2010) referred two specimens from Oakham Quarry to M. bucklandii based on autapomorphies (ischium SDM 44.20 [O] and metatarsal III BMNH R9665 [R]), but refrained from referring additional elements from this quarry as he notes some "can be referred to a second, unnamed taxon (R. B. J. Benson, unpubl. data)." This near certainly refers to "reynoldsi", whose intended holotype is an ilium from Oakham Quarry (SDM 44.19). Further study by Benson and/or Pickering may clarify the identity of the other Oakham Quarry elements. The material Welles and Pickering referred to "reynoldsi" is here provisionally retained in the species, as none has been usefully described in the published literature.


Megalosaurus bucklandii material referred to "Metriacanthosaurus" "reynoldsi" by Welles and Pickering (1999).  Not to scale.  For specimen numbers, see list above.  Taken from Benson (2010), except F, K and M from Reynolds (1939) and P and Q from Benson (2009).

The identity of SDM 44.19 is difficult to determine from the published illustration, since many useful ilial characters would only be visible in medial or ventral views. However, it is a tetanurine based on the lack of a strong crest between the supracetabular crest and brevis fossa, and is not a coelurosaur based on the large ischial peduncle and widely exposed brevis fossa in lateral view. It differs from Megalosaurus and Metriacanthosaurus in many of the same ways- anteroposteriorly narrow pubic peduncle; broad medial wall to the acetabulum, especially posteriorly; longer ischial peduncle; broad esposure of medial wall of the brevis fossa; low ilial blade. It is more similar to Metriacanthosaurus in the wide subpreacetabular notch, and anteroposteriorly wide ischial peduncle, but shares a series of short vertical ridges above the acetabulum with Megalosaurus (albeit more pronounced). Pickering's (DML, 2002) only ilial character for Metriacanthosaurus is "ilium + ischium fused", which isn't true of M. parkeri or "reynoldsi." Thus is seems whatever "reynoldsi" is, there's no reason to refer it to Metriacanthosaurus. A greater resemblence is seen to Eustreptospondylus, which shares the narrow pubic peduncle, broad esposure of medial wall of the brevis fossa, and low ilial blade. Another similar ilium is that of "Szechuanosaurus" zigongensis, which shares the broad medial wall to the acetabulum, longer ischial peduncle, and low ilial blade. Which of these two taxa it is more closely related to will require study of the specimen itself and additional specimens from Oakham Quarry. For now it is best placed either in basal Tetanurae or Eustreptospondylinae.


Ilia compared in right lateral view- A. Megalosaurus bucklandii (after Benson, 2010). B. Metriacanthosaurus parkeri (modified from Walker, 1964). C. "Metriacanthosaurus" "reynoldsi" (modified from Reynolds, 1939). D. Eustreptospondylus (after Sadlier et al., 2008). E. "Szechuanosaurus" zigongensis (modified after Gao, 1993).

The illustrated Oakham tooth (BMNH or SDM colls) is short (height/FABL 1.66) and moderately recuved with perpendicular serrations on at least the apical half of the distal carina. Only light longitudinal striations are indicated on the enamel. At least one of the scapulae (SDM 44.16 and 44.17) is unfused to the coracoid, though it is unknown if these were from Oakham Quarry, or merely from New Park Quarry and unreferred by Benson to Megalosaurus.

References- Lydekker, 1888. Catalogue of the Fossil Reptilia and Amphibia in the British Museum (Natural History), Cromwell Road, S.W., Part 1. Containing the Orders Ornithosauria, Crocodilia, Dinosauria, Squamata, Rhynchocephalia, and Proterosauria. British Museum of Natural History, London. 309pp.

Gardiner, 1937. Reptile-bearing oolite, Stow. Reports of the British Association for the Advancement of Science (Blackpool). 1936, 296.

Gardiner, 1938. Reptile-bearing oolite, Stow. Reports of the British Association for the Advancement of Science (Nottingham). 1937, 290.

Reynolds, 1938. A collection of reptilian bones from the Oölite near Stow-in-the-Wold, Glos. Reports of the British Association for the Advancement of Science. 1937, 356-357.

Reynolds, 1939. A collection of reptile bones from the Oolite near Stow-on-the-Wold, Gloucestershire. Geological Magazine. 76, 193-214.

Pickering, 1995. Jurassic Park: Unauthorized Jewish Fractals in Philopatry. A Fractal Scaling in Dinosaurology Project, 2nd revised printing. Capitola, California. 478 pp.

Welles and Pickering, 1999. Megalosaurus bucklandii. Private publication of Stephen Pickering, An extract from Archosauromorpha: Cladistics & Osteologies. A Fractal Scaling in Dinosaurology Project. 119 pp.

Day and Barrett, 2004. Material Referred to Megalosaurus (Dinosauria: Theropoda) from the Middle Jurassic of Stonesfield, Oxfordshire, England: one taxon or two? Proceedings of the Geologists' Association. 115, 359-366.
Benson, 2009. An assessment of variability in theropod dinosaur remains from the Bathonian (Middle Jurassic) of Stonesfield and New Park Quarry, UK and taxonomic implications for Megalosaurus bucklandii and Iliosuchus incognitus. Palaeontology. 52(4), 857-877.

Benson, 2010. A description of Megalosaurus bucklandii (Dinosauria: Theropoda) from the Bathonian of the UK and the relationships of Middle Jurassic theropods. Zoological Journal of the Linnean Society. DOI 10.1111/j.1096-3642.2009.00569.x

Pickering, in prep. Mutanda Dinosaurologica.

Saturday, April 3, 2010

Pickering's taxa 2: Metriacanthosaurus brevis

Part 2 of Pickering's taxa.  The comments on all these are going to have a similar section of course, since they all involve the same collection of Pickering manuscripts.

Megalosaurus Buckland, 1824
M. bucklandii Mantell, 1827
= Metriacanthosaurus "brevis" Welles, Powell and Pickering vide Pickering 1995
Middle Bathonian, Middle Jurassic
Taynton Limestone Formation (=Stonesfield Slate), England

Referred- (BMNH 31806) femur (805 mm) (Owen, 1857)
(BMNH 31809) tibia (645 mm) (Owen, 1857)
(BMNH 31811; intended holotype of Metriacanthosaurus "brevis") partial ilium (Owen, 1857)
(OUM J13562) tibia (660 mm) (Galton and Molnar, 2005)
(OUM J29888) (scapulocoracoid 795 mm) partial scapula, partial coracoid (Day and Barrett, 2004)

Comments- Owen (1857) originally described Megalosaurus ilia as coracoids, noting three specimens were in the BMNH and figuring one. Lydekker (1888) recognized these as ilia and incorrectly listed the one illustrated by Owen as BMNH 31811, though Pickering (DML, 2002) notes it is actually BMNH R1100. BMNH 31811 remained as a specimen of Megalosaurus bucklandii until Pickering credited the name Metriacanthosaurus brevis to English theropod material in his 1995 unpublished bibliographic manuscript. It was later used in the comparative section of another unpublished manuscript (Welles and Pickering, 1999). This paper was largely extracted from the European megalosaur manuscript Welles and Powell worked on in the 1970s but never published, specifically the Megalosaurus redescription section. Pickering intends to publish an updated version of the megalosaur manuscript as Mutanda Dinosaurologica, and has posted small excerpts including the diagnosis of Metriacanthosaurus "brevis" online (DML, 2002). In any case, the name is a nomen nudum as Pickering didn't follow ICZN Article 7 Recommendation 7a, Article 8a or Recommendation 8A. Pickering says of M. "brevis" and Metriacanthosaurus parkeri, "their great height and shortness -- diagnostic for Metriacanthosaurus -- separates them from ilia of Megalosaurus bucklandii and Allosaurus." Additionally, Allain and Chure (2002) stated BMNH 31811 and R1100 (misidentified as OUM J13560) are "quite different from one another in shape in proportions." However, Day and Barrett (2004) found the shortness was an illusion caused by a broken postacetabular process and a plaster reconstructed preacetabular process. Benson (2009) agreed and also found it shared an autapomorphy with other M. bucklandii ilia- a series of posterodorsally oriented ridges that give the posterior part of the median ridge an undulating texture. Indeed, the characters Pickering lists as distinguishing M. "brevis" from M. parkeri are largely also those that distinguish M. bucklandii from M. parkeri (nearly straight upper margin; taller preacetabular process), or don't distinguish M. "brevis" from M. bucklandii (narrower notch between preacetabular process and pubic peduncle; longer, lower acetabulum; 250 mm long). So I see no reason to support M. "brevis" and synonymize it with M. bucklandii.


Top left- photo and line drawing of intended holotype of Metriacanthosaurus "brevis" BMNH 31811 (after Benson, 2009).
Bottom left- Megalosaurus bucklandii ilium OUM J13560 (after Benson, 2009) and superimposed image of it and "brevis" specimen to show similarity except for broken ends.
Top right- Metriacanthosaurus "brevis" referred femur BMNH 31806 in anterior, mdial, lateral, posterior and distal views (after Benson, 2010).
Bottom right- Metriacanthosaurus "brevis" referred tibia BMNH 31809 in anterior, lateral, posterior, medial, proximal and distal views (after Benson, 2010).

Pickering also referred several other specimens to M. "brevis". OUM J29888 is a pectoral girdle which Day and Barrett and Benson couldn't distinguish from M. bucklandii. BMNH 31806 is a femur which Allain and Chure stated differs from the paralectotype in being straight with a medially directed head. Day and Barrett (2004) used this as the basis for their morphotype A femora, but Benson (2009) found the head orientation to be individual variation and the curvature of type B femora to be taphonomic. Additional differences between morphotype A and B femora were also found to be preservational or individual variation (see below), and Benson (2009, 2010) referred both types to M. bucklandii. Ironically, M. parkeri's femur has a sigmoid shaft, though it does have a medially directed head. BMNH 31809 and OUM J13562 are tibiae which Benson (2009, 2010) referred to M. bucklandii and which share a bulbous fibular crest with that taxon. BMNH 31809 differs from M. parkeri in having a smaller cnemial crest which is not as laterally angled and a smaller and more laterally placed fibular crest. Thus all supposed Metriacanthosaurus "brevis" material is referrable to Megalosaurus bucklandii and does not bear particular resemblence to Metriacanthosaurus itself. Coincidentally, BMNH 31806 and 31809 are the femur and tibia illustrated as examples of those elements in Benson's (2010) redescription of M. bucklandii, though the other tibia and the pectoral girdle remain unillustrated.

References- Owen, 1857. Monograph on the Fossil Reptilia of the Wealden Formations. Part III. Dinosauria (Megalosaurus). Palaeontographical Society Monographs. 34, 1-26.

Lydekker, 1888. Catalogue of the Fossil Reptilia and Amphibia in the British Museum (Natural History), Cromwell Road, S.W., Part 1. Containing the Orders Ornithosauria, Crocodilia, Dinosauria, Squamata, Rhynchocephalia, and Proterosauria. British Museum of Natural History, London. 309pp.

Pickering, 1995. Jurassic Park: Unauthorized Jewish Fractals in Philopatry. A Fractal Scaling in Dinosaurology Project, 2nd revised printing. Capitola, California. 478 pp.

Welles and Pickering, 1999. Megalosaurus bucklandii. Private publication of Stephen Pickering, An extract from Archosauromorpha: Cladistics & Osteologies. A Fractal Scaling in Dinosaurology Project. 119 pp.

Allain and Chure, 2002. Poekilopleuron bucklandii, the theropod dinosaur from the Middle Jurassic (Bathonian) of Normandy. Palaeontology. 45, 1107-1121.

Pickering, DML 2002. http://dml.cmnh.org/2002Mar/msg00553.html

Day and Barrett, 2004. Material Referred to Megalosaurus (Dinosauria: Theropoda) from the Middle Jurassic of Stonesfield, Oxfordshire, England: one taxon or two? Proceedings of the Geologists' Association. 115, 359-366.
Galton and Molnar, 2005. Tibiae of small theropod dinosaurs from Southern England, from the Middle Jurassic of Stonesfield near Oxford and the Lower Cretaceous of the Isle of Wight: In Carpenter (ed). The Carnivorous Dinosaurs. 3-22.

Benson, 2009. An assessment of variability in theropod dinosaur remains from the Bathonian (Middle Jurassic) of Stonesfield and New Park Quarry, UK and taxonomic implications for Megalosaurus bucklandii and Iliosuchus incognitus. Palaeontology. 52(4), 857-877.

Benson, 2010. A description of Megalosaurus bucklandii (Dinosauria: Theropoda) from the Bathonian of the UK and the relationships of Middle Jurassic theropods. Zoological Journal of the Linnean Society. DOI 10.1111/j.1096-3642.2009.00569.x

Pickering, in prep. Mutanda Dinosaurologica.

Thursday, April 1, 2010

Pickering's taxa 1: Megalosaurus phillipsi

As part of the reorganization of basal tetanurines on my site, I'm going through several taxa proposed by Stephen Pickering.  Pickering's certainly a character, as any dinosaur paleontologist who's been online in the last decade can tell you.  He has the manuscripts from Welles and Powell's European theropod study in the 70's which was never published, and he has distributed them in the form of privately printed papers sent to some of his colleagues.  This has the effect of keeping his work from most interested parties, since libraries or internet pages do not host it.  It seems there IS a good reason for ICZN Article 8a after all.  While I unfortunately don't have a copy of his 1995 or seemingly more useful 1999 works (though not for lack of trying), I do know which specimens his taxa are based on.  Thus we begin our journey into Pickeringdom...

"Megalosaurus" “phillipsi” Welles, Powell and Pickering vide Pickering, 1995
Kimmeridgian, Late Jurassic
Kimmeridgian Clay, England
Material- (OUM J29886) tibia (740 mm) (Huene, 1926)
....(OUM J13586) metatarsal II (360 mm), incomplete metatarsal III, incomplete metatarsal IV (Phillips, 1871)

Diagnosis- (from Pickering, DML 2002) cnemial crest more laterally angled.
(suggested) metatarsal II transversely narrower in proximal view; a wide lateral flare to the ventral rim of the lateral ligament pit on metatarsal II.

Other diagnoses- Pickering has listed his intended diagnosis for this species online (DML, 2002). Of his listed characters, the tibia does not seem noticably straighter in "phillipsi" than in Megalosaurus or Torvosaurus. The fibular crest begins at a similar position proximally. I cannot confirm the presence of a pit in the astragalar facet in M. bucklandii, and the "concavity of the distal end is wider" in Torvosaurus and "Brontoraptor" as well. The latter is also true of the medial malleolus, which "does not extend so far below the medial end." The tibia is equally robust in "Brontoraptor", Torvosaurus tanneri and T? sp. ML 430 from Portugal, which also share the transversely expanded lateral condyle. While the fibular crest extends more distally than in M. bucklandii, it does not do so more than "Brontoraptor" or ML 430.

Comments- OUM J29886 is intended as the holotype, though Huene (1926) felt they belonged to the same individual.

Phillips (1871) illustrated the metatarsus as Megalosaurus in figure 68. Huene (1926) later illustrated both the tibia and metatarsus as Megalosaurus bucklandi, incorrectly stating they derive from the Stonesfield Slate (Pickering, DML 2002). Huene also lists the metatarsals again as Megalosaurus sp. under entry 54 of his list, which also get listed as ?Megalosaurus sp. by him in 1932. Pickering (1995) first mentioned the name Megalosaurus phillipsi in an unpublished bibliographic manuscript. It was later used in the comparative section of another unpublished manuscript (Welles and Pickering, 1999). This paper was largely extracted from the European megalosaur manuscript Welles and Powell worked on in the 1970s but never published, specifically the Megalosaurus redescription section. Pickering intends to publish an updated version of the megalosaur manuscript as Mutanda Dinosaurologica, and has posted small excerpts including the diagnosis of "phillipsi" online (DML, 2002). In any case, the name is a nomen nudum as Pickering didn't follow ICZN Article 7 Recommendation 7a, Article 8a or Recommendation 8A. Curiously, Benson's (2010) recent redescription of Megalosaurus does not even mention the specimen, though it does lack the only character in his diagnosis of M. bucklandii for which it can be checked- complementary groove and ridge structures on the articular surfaces between metatarsals II and III.


Tibiae in anterior and proximal views of (from left to right) "Brontoraptor" (after Siegwarth et al., online), Portuguese Torvosaurus? sp. ML 430 (after Antuns and Mateus, 2003), Torvosaurus tanneri (after Britt, 1991), "Megalosaurus" "phillipsi" (after Huene, 1926), and Megalosaurus bucklandii (modified from Benson, 2010).

When entered into my saurischian supermatrix, "phillipsi" emerges in a polytomy with non-spinosaurid megalosauroids. This specimen will be compared to Megalosaurus bucklandii, Torvosaurus and "Brontoraptor" (note Pickering and Welles synonymized the first two at least), as it differs markedly from Eustreptospondylus (used as the outgroup comparison), while Magnosaurus and Dubreuillosaurus are too incomplete to be compared usefully and Afrovenator remains largely undescribed. Poekilopleuron differs in having a proximal corner on its medial malleolus and an astragalar facet that extends far up the medial edge of the tibia. As noted above in the 'other diagnoses' section, "phillipsi" apomorphically resembles Morrison megalosaurs and ML 430 more than Megalosaurus in being robust and having a transversely expanded lateral condyle. It apomorphically resembles "Brontoraptor" and ML 430 more in having a distally extending fibular crest, but is primitively more like Megalosaurus than any of these taxa in having a low angled medial malleolus. The proximodistally wide medial side to the astragalar facet is most similar to "Brontoraptor" and Torvosaurus, and the fibular crest lacks the apomorphically bulbous shape of Megalosaurus'. In proximal view, the incisura tibialis is plesiomorphically shallower than Megalosaurus as in Torvosaurus and "Brontoraptor", but the shape is plesiomorphically more similar to Megalosaurus than "Brontoraptor" in having a narrower cnemial crest and more posteriorly extensive medial condyle.



Left metatarsi in proximal, anterior and distal views of (from left to right) Torvosaurus tanneri (after Britt, 1991), "Megalosaurus" "phillipsi" (after Huene, 1926) and Megalosaurus bucklandii (after Benson, 2010).

Metatarsal II is of equal robusticity to Megalosaurus, unlike Torvosaurus' apomorphically massive element. It apomorphically shares the medial flare to the ventral rim of the collateral ligament pit with Torvosaurus though. It differs from both in being transversely narrower proximally and having a wide lateral flare to the ventral rim of the opposite collateral ligament pit. In proximal view, Megalosaurus and "phillipsi" both have a posterior concavity on metatarsal II, and share a convex anterior edge, as in the outgroup. Distally, it is primitively deeper than in either Megalosaurus or Torvosaurus. Metatarsal III is primitively more medially bowed than either, and is again less robust than Torvosaurus'. Proximally, metatarsal III is closer to Torvosaurus in having an apomorphic highly concave lateral margin and lacking the apomorphic sinuous medial margin of Megalosaurus. It has a primitively blunter posteromedial corner than either of them. Distally, the lateral condyle is apomorphically narrower as in Torvosaurus. Metatarsal IV has an apomorphically concave lateral edge as in Megalosaurus, unlike the sinusoidal edge of Torvosaurus. The distal shaft width is intermediate, and the articular end plesiomorphically expands transversely less than in Megalosaurus.
 
Ignoring the symplesiomorphies then, "phillipsi" shares five apomorphic states with Torvosaurus, and only one with Megalosaurus. It also shares these apomorphies with "Brontoraptor" and ML 430 where known, and shares the distally projecting fibular crest uniquely with those two specimens. I conclude Welles, Powell and Pickering were correct to refer "phillipsi" to their more inclusive version of Megalosaurus, but if Torvosaurus is separated as most modern workers do, it would be better referred to that genus. "Brontoraptor" has been recently assumed to be synonymous with Torvosaurus, and if so the features "phillipsi" shares with the former to the exclusion of the latter may be individual variation or incorrectly illustrated for "Brontoraptor". However, the fact Portuguese tibia ML 430 has the same characters suggests this may not be the case. Whether ML 430 should be referred to "phillipsi" is an interesting question, as they are both from Late Jurassic Europe. While the distally extensive fibular crest might suggest so, the broadly flared medial malleolus and laterally straight lateral malleolus of ML 430 resemble Torvosaurus more, while the medially narrow astragalar facet is more like Megalosaurus than any torvosaur. Both "phillipsi" and ML 430 are best referred to Torvosauridae.

References- Phillips, 1871. Geology of Oxford and the Valley of the Thames. Clarendon Press, Oxford.

Huene, 1926. The carnivorous Saurischia in the Jura and Cretaceous formations, principally in Europe. Revista del Museo de La Plata. 29, 35-167.

Huene, 1932. Die fossile Reptil-Ordnung Saurischia, ihre Entwicklung und Geschichte. Monographien zur Geologie und Palaeontologie. 4(1), viii + 361 pp.

Pickering, 1995. Jurassic Park: Unauthorized Jewish Fractals in Philopatry. A Fractal Scaling in Dinosaurology Project, 2nd revised printing. Capitola, California. 478 pp.

Welles and Pickering, 1999. Megalosaurus bucklandii. Private publication of Stephen Pickering. An extract from Archosauromorpha: Cladistics & Osteologies. A Fractal Scaling in Dinosaurology Project. 119 pp.

http://dml.cmnh.org/2002Mar/msg00553.html

Benson, 2010. A description of Megalosaurus bucklandii (Dinosauria: Theropoda) from the Bathonian of the UK and the relationships of Middle Jurassic theropods. Zoological Journal of the Linnean Society. DOI 10.1111/j.1096-3642.2009.00569.x

Pickering, in prep. Mutanda Dinosaurologica.