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The Tadpoles of Bufo cognatus Say

BY
HOBART M. SMITH


University of Kansas Publications
Museum of Natural History

Volume 1, No. 3, pp. 93-96, 1 figure in text

August 15, 1946


UNIVERSITY OF KANSAS
LAWRENCE
1946




UNIVERSITY OF KANSAS PUBLICATIONS, MUSEUM OF NATURAL HISTORY

Editors: E. Raymond Hall, Chairman, Donald S. Farner, Donald F. Hoffmeister

Volume 1, No. 3, pp. 93-96

Published August 15, 1946


UNIVERSITY OF KANSAS
Lawrence, Kansas


PRINTED BY
FERD VOILAND, JR., STATE PRINTER
TOPEKA, KANSAS
1946

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The Tadpoles of Bufo cognatus Say

By

HOBART M. SMITH


The tadpoles of this species have been described by Bragg (Copeia,
1936: 14-20, figs. 1-13; Amer. Midl. Nat., 18:273-284, figs. 1-5,
1937). The drawings and descriptions of the mouthparts, however, appear
to have been taken from dried, or immature, or transforming
individuals, for they do not agree among themselves nor do they agree
with larvae obtained in the field and now in the Museum of Natural
History of the University of Kansas.

At hand are two series of tadpoles of this species; one series was
collected July 2, 1938, 1.5 miles east of Meade County State Park,
Kansas, and the other lacks data. The second lot contains numerous
sizes of tadpoles from 14 mm. to 31 mm., and several transforming
specimens which clearly possess the pattern so typical of this species.

[Illustration: FIG. 1.--Mouthparts of a tadpole of _Bufo cognatus_.
Disk widely spread. Approximately × 45.]

Mouthparts in both series (consisting all told of about 200 specimens)
are fairly constant except in the transforming and extremely young
specimens. The accompanying figure shows them as seen with the mouth
disk widely spread. The indentations at the corners of the mouth in the
papillary fringe are more prominent when the mouthparts are less
extended. The outer row of teeth of the lower labium is sometimes a
little shorter or longer than the figure shows, but the average is
about as indicated. The extent of the medial edge of the papillae on
the lower labium varies somewhat; in some, the papillae barely reach
the level of the ends of the outer row of teeth, while in others they
overlap the ends slightly.

Measurements agree with those given by Bragg, except that appearance of
the hind legs occurs at about 15 mm.; the fore legs appear at about 28
mm. A pattern recognizably similar to that of the adult is evident at
about 20 mm.

These tadpoles show such a striking similarity to those referred by
Wright to _Bufo compactilis_ Wiegmann (Proc. U. S. Nat. Mus., 74:4, pl.
5, fig. 6, 1929) that their conspecificity is suggested. If on the
other hand, the specimen figured by Wright is properly identified, then
the two species must in reality be very closely related. A direct
comparison of positively identified tadpoles of each species is much to
be desired.


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