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Herrerasaurus



     First of all, thanks to eveybody who sent me references.  I've got 
enough Herrasaurus references at least to get started.  The most useful 
references are Sereno & Nova's papers in Science (1992, 258: 1137-1140) 
and JVP (1993, 13(4): 400-476) dealing largely with the most recently 
discovered and spectacular H.ischigualastensis (PVSJ 407).  Some interesting 
points:
      Sereno and Novas consider Herrerasaurus not only to be a true 
saurischian ("subnarial foramen between the premaxilla and maxilla, 
hyposphene-hypantrum articulations in the dorsal vertebrae, epipophyses 
on mid- and posterior cervical vertebrae, and an elongate manus that 
approaches or exceeds half the length of the proximal part of the 
forelimb" Science article, p 1139) but imply that it is a true (basal) 
theropod as well ("pubic foot, elongate prezygapophyses in the distal 
caudal vertebrae" Science, p 1139) rather than a basal dinosaur 
independant of either Saurischia and Ornithischia.  They list the 
following dinosaurian synapomorphies for Herrerasaurus: "absence of the 
prefrontal...extension of the abductor musculature onto the frontal, 
lateral exposure of the quadrate head, and a reduction of the 
posttemporal opening to a foramen...addition of the dorsal vertebrae to 
the sacrum, an elongate deltopectoral crest on the humerus, loss of ungal 
on the fourth digit of the hand, a brevis fossa on the illium, a 
subrectangular femoral head, a cnemial crest on the tibia, and an 
ascending process on the astragalus." Science, p. 1138) 
      Novas considers the other Ischigualasto carnivores 
Frenguellisaurus (Reig, 1963), Ischisaurus (Novas, 1986), and cf. 
Staurikosaurus (Brinkman & Sues, 1987) to belong to Herrerasaurus 
(JVP, 401-402).  I'm using the dinosaur genera list as my guide for 
which genera to mention, so I might make up seperate references for 
Fruenguellisaurus and Ischisaurus (Staurikosaurus is a valid genus from the
Santa Maria Formation) anyway, and simply say they are probably referrable to 
Herrerasaurus.          
      I'm unsubscibing tonight until Christmas vacation is over in 
January, so I probably won't receive any responses to this posting.  One 
thing I plan to ask about when I get back is a taxonomic framework for 
the DinoPages.  I'm thinking about using two or three seperate models that 
are more or less representative of differing opinions.  Its something I need to 
discuss with Doug before I get back on it.
      Later!

LN Jeff