Re: Megalosaurids

["Mickey Mortimer" <Mickey_Mortimer111@msn.com>]

Nicholas Gardner wrote-

> 1.How many species are valid within Megalosaurus?

At least one- M. bucklandi.
Pickering has named another species- M. phillipsi, but whether this soon to
be described species will be accepted by the paleoontological community is
unknown.
Other potentially correctly assigned species are M. "dapukensis", M.
insignis, M. pombali and M. "tibetensis".  But the first and last are nomina
nuda, and the other two are known from fragmentary remains.

> 2.What horizon does it hail from?

The holotype of M. bucklandi is from the Middle Bathonian Stonesfield Slate
in England.  Other possibly correctly referred material is from the
Aalenian-Bajocian Inferior Oolite, the Early Bathonian Chipping Norton
Formation, the Late Bathonian Forest Marble and the Late Bathonian Cornbrash
Formation.
Megalosaurus phillipsi is from the Kimmeridgian Kimmeridge Clay of England.

> 5.What other species of amniotes were present?

Dinosaurs-
Streptospondylus? cuvieri
"Walkersaurus" hesperis
Magnosaurus nethercombensis
Eustreptospondylus oxoniensis
Metriacanthosaurus "brevis"
Metriacanthosaurus "reynoldsi"
Iliosuchus incognitus
Richardoestesia? sp.
unnamed troodontid?
unnamed velociraptorine
Cetiosaurus medius
Cetiosaurus? oxoniensis
Cardiodon rugulosus
Cetiosauriscus glyptonensis
Cetiosauriscus longus
Bothriospondylus robustus
Lexovisaurus? vetustus

> 6.What is the estimated length and mass of Megalosaurus?

The various specimens I have measurements for come out between seven and
nine meters long.  Estimating length is uncertain enough, the mass would be
somewhere over a half ton to less than two tons, depending on the specimen.

> 7.How much material has been assigned to the valid species?

For M. bucklandi, Pickering
(http://www.cmnh.org/dinoarch/2002Mar/msg00553.html) writes- 2 maxillae;
left jugal; 3 partial mandibles (1 lost); 1 cervical; 3 dorsals; 3 sacrums;
2 caudals; 6 pectoral girdles (variably complete); 2 humeri; 1 ulna; 6 ilia
(variably complete); 3 pubis (none complete); 2 ischia; 12 femora (4 lost,
all variably eroded); 6 tibiae (variably complete, 1 lost); 2 metatarsals;
lost pedal ungual; pedal phalanx.
And for M. phillipsi, a tibia and metatarsus.
I never did thank Stephen for that post.....  Thanks!

> 8.Is Megalosauridae a valid grouping?  If so, what supports it?
> 9.Should Torvosaurus and Poekilopleuron be sunk into Megalosauridae?

Perhaps.  Characters commonly used to support it include the anterior
expansion on the central part of the scapular blade (Megalosaurus, Edmarka),
short forearms (Megalosaurus, Poekilopleuron, Torvosaurus), wide pubes
(Megalosaurus, Torvosaurus) and down-kinked ischia (Megalosaurus ,
Torvosaurus).  Both Allain and Pickering will elaborate on the family and
what it contains and is diagnosed by soon.

Mickey Mortimer