The Coal Measures Amphibia of North AmericaMoodie, Roy Lee
Science
The Coal Measures Amphibia of North America
Moodie, Roy Lee
Amphibians, Fossil -- North America; Paleontology -- Carboniferous; Paleontology -- North America
The matter of especial interest in connection with this second specimen
is the remarkably perfect preservation of the alimentary canal, which is
entire, except for the very anterior end of the œsophagus. The posterior
portion of the œsophagus, which measures 3.5 mm., is clearly preserved.
Its anterior end is thrown around posteriorly and indicates that this
end was loosened after death and became displaced before fossilization.
The length preserved may represent the entire œsophagus. The œsophagus
is constricted before it enters the stomach, which shows the usual
curvature found in modern salamanders. The stomach measures 6 mm. in
length by 2 mm. in breadth, and consists of a single enlargement as in
the modern _Amblystoma punctatum_. It increases in size somewhat toward
the pyloric end and then very gradually constricts to the pylorus. Three
divisions of the small intestine can be seen. The most anterior one,
corresponding to the duodenum, is segmented, as though the intestine had
been filled with food before interment. The remainder of the intestine,
corresponding to the ilium, is looped in the form of two figures =8= which
are superimposed, with the upper portions of the =8= at right angles to
each other. The rectum is clearly discernible, though its lower portion
is somewhat obscured by having the lower part of the upper loop of the
intestine lying over it. The anus lies at a distance of 1.5 mm. posterior
to the transverse line from, the upper end of the femur, and is quite well
back on the tail, as in modern salamanders. In this specimen also occur
two oval bodies which may be identified as the lower ends of the oviducts,
thus indicating, in all probability, that the animal was a female.
[Illustration: Fig. 14. Mazon Creek Amphibia.
A. Third specimen of _Eumicrerpeton parvum_ Moodie, which exhibits
the alimentary canal well preserved. × 2. Original in United
States National Museum. _a_, anus; _f_, femur; _h_, humerus;
_ic_, interclavicle; _in_, intestine; _m_, mandible; _or_, orbit;
_st_, stomach; _t_, tibia and fibula.
B. Type specimen of _Amphibamus thoracatus_ Moodie. Original in
United States National Museum. × 2 (For description see P. 132.)
]
A dissection of several species of modern caudates has resulted in
the discovery that the adult condition of the alimentary canal of all
the species dissected (_Amblystoma punctatum_, _Necturus maculosus_,
_Diemyctylits torosus_, _D. viridescens_, etc.) is much more complex than
that exhibited by the specimen under discussion. A very near approach to
the condition found in _Eumicrerpeton parvum_ is found in an immature
branchiate individual of _Diemyctylits torosus_, 56 mm. in length, from
a fresh-water pond on Mount Constitution, on Orcas Island, Puget Sound,
Washington.
Public-domain text, read in full here on John Shaqi.
Reviews
Reviews
No reviews yet
Be the first to share your thoughts on this work.
Elsewhere in the archive
Join the Discussion
Join the discussion
Sign in to leave a comment or review.
Sign InorCreate an account