A new generic and family position for Bufo Borbonica

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ZOOLOGICAL SERIES

OF iasiTY OF ILLINOIS

FIELD MUSEUM OF NATURAL HISTORY

Volume XX CHICAGO, MAY 15, 1935 No. 12

A NEW GENERIC AND FAMILY POSITION FOR
BUFO BORBONICA

BY D. DWIGHT DAVIS

ASSISTANT, DIVISION OF OSTEOLOGY

Recent studies, as yet unpublished, have revealed that Bidder's
organ — the small structure lying in front of the gonads in certain
salientians — is an organ peculiar to the Bufonidae. Among many
species of bufonids and leptodactylids examined in this connection,
I have found but one exception to this rule. The long-legged East
Indian toad Bufo borbonica lacks both Bidder's organ and the
elongation of the testes characteristic of toads. Further examina-
tion reveals that these features are by no means the most extraor-
dinary points in the anatomy of this animal, since in addition it is
found to have a fully firmisternal pectoral girdle (fig. 8).

Through the courtesy of Mr. Arthur Loveridge I have been able
to examine the series of this species in the Museum of Comparative
Zoology, consisting of four specimens from Kuan Nieng Province,
Siam. I am also indebted to Dr. Leonhard Stejneger for the loan
of five specimens from Trong, Lower Siam, in the collections of the
National Museum, and for much-appreciated advice on the status
of the name Hylaplesia. Mr. H. W. Parker, of the British Museum
(Natural History), has been kind enough to examine specimens of
Bufo borbonica for me. He confirms my findings, pointing out some
additional characters, which I have incorporated in the description.
A great deal of invaluable advice and criticism has been given by
Mr. Karl P. Schmidt, Assistant Curator of Amphibians and Reptiles
in Field Museum, and to him I am especially grateful.

The taxonomic history of this toad has been decidedly erratic,
and since it has resulted in some confusion in the literature, it may
well be clarified here.

The generic name Hylaplesia was listed by Schlegel (1826a and b)
in two papers published simultaneously in German and French.1

1 In the French edition the name appears as Hysaplesia, apparently through
a misprint.

No. 345 87

88 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. XX

His report was based largely on an unpublished manuscript by Boie,
who in turn had drawn freely on a manuscript by his associates
Kuhl and van Hasselt. Schlegel credits the genus Hylaplesia to
Boie and, following Boie's manuscript, the species borbonica to
Kuhl and van Hasselt. Schlegel's borbonica, however, is a nomen
nudum without status. Tschudi (1839) next lists borbonica, together
with sufficient description to validate the name, again referring it
to Hylaplesia. Tschudi is therefore the author of the name borbonica,
but the generic name Hylaplesia is a synonym of Dendrobates, and
cannot be revived for borbonica, in spite of Peters's attempt to do so
(Peters, 1863, p. 81). The species was referred to the genus Bufo
by Cope (1867, p. 193), in which he was followed by Boulenger
(1882, p. 286). Bufo borbonica was transferred later to Nectophryne
by van Kampen (1911, p. 75) and returned by Smith (1925, p. 30)
to Bufo, where it has since remained.

The structure of the pectoral girdle, the urogenital system, and
other less conspicuous features of its anatomy, show that the species
borbonica cannot be retained in any of the genera to which it has
heretofore been referred; nor does it show affinities close enough to
warrant allocating it to any other genus, as will be shown below.
Since it cannot be referred to any existing genus, it is necessary to
erect for it a new one.

Cacophryne gen. nov.

Type, Hylaplesia borbonica Tschudi, from the East Indies.

Diagnosis. — Vertebral column procoelous. Pectoral girdle com-
pletely firmisternal; sternum slender and cartilaginous; omosternum
absent. Sacral diapophyses widely expanded; coccyx and sacrum
fused. Maxillary and vomerine teeth lacking; prevomer small,
ethmoid entire, palatine present. Ear complete. No palatal folds;
eustachian tubes present. Terminal phalanges simple. No inter-
calary cartilages. Pupil horizontal. Narrow, inconspicuous, parotid
glands present. Habitus slender, with elongated limbs.

Cacophryne borbonica (Tschudi).

Hylaplesia borbonica Schlegel, Isis, 20, p. 294, 1826 — nomen nudum.
Hysaphsia borbonica Schlegel, Bull. Sci. Nat. FeYussac, 9, p. 239, 1826 —
nomen nudum.

Hylaplesia borbonica Tschudi, Mem. Soc. Sci. Nat. Neuchatel, 2, p. 70, 1839;

Peters, Monatsber. Berlin Akad., 1863, p. 81.
Bufo borbonicus Cope, Jour. Acad. Nat. Sci. Phila., 6, p. 193, 1867; Boulenger,

Cat. Batr. Sal. Brit. Mus., p. 286, 1882; Horst, Notes, Leyden Mus., 5,

p. 236, 1883.

PI

1935

.

POSITION OF BUFO BORBONICA — DAVIS

89

Bufo borbonica M. A. Smith, Sarawak Mus. Jour., 3, p. 30, 1925; Bull. Raffles

Mus., 3, p. 130, 1930.
Nectophryne borbonica van Kampen, Notes, Leyden Mus., 34, p. 75, 1911;

Amphibia Indo-Austr. Arch., p. 70, fig. 7, 1923.
Nectophryne sumatrana van Kampen, Natuurk. Tijdschr. Ned.-Ind., 69, p.

19, pi. 1, fig. 1, 1910.
Bufo jerboa Boulenger, Proc. Zool. Soc. Lond., 1890, p. 328, pi. 25, fig. 3;

Vert. Fauna Malay Pen., Kept, and Batr., p. 271, 1912; van Kampen,

Amphibia Indo-Austr. Arch., p. 76, 1923; Noble, Biol. Amphibia, p. 502,

fig. 161, 1931.

The problem of the allocation of this genus to the proper family
is far from simple. The structure of the urogenital system alone

mm* BF <

MAY. 3 11935

OF ILLINOIS

FIG. 8. Ventral view of shoulder girdle of Cacophryne borbonica. U. S. National Museum No. 24040.

seems sufficient evidence to warrant the exclusion of borbonica from
the family Bufonidae. On examination I find, furthermore, that the
pectoral girdle is completely firmisternal, which not only reinforces
this conclusion, but also eliminates the possibility of a reference to
the Leptodactylidae. The procoelous vertebrae ally it clearly to
these families, although Parker (1934) has shown that this con-
dition of the vertebral column is found also in many microhylid
genera. Examination of the thigh musculature, however, shows
that the tendon of the semitendinosus overlies that of the gracilis,
thus throwing out the diplasiocoelous families Ranidae, Polypeda-
tidae, and Microhylidae as possible relatives (Parker, 1934, p. 6).
By elimination, a single family, the Atelopodidae, remains, and
here apparently is its true relationship. The species under con-

90 FIELD MUSEUM OF NATURAL HISTORY— ZOOLOGY, VOL. XX

sideration has in fact a somewhat striking external resemblance to
members of the genus Atelopus.

The reference of Cacophryne to the Atelopodidae results in what
seems to be a distributional anomaly, since all atelopodids hitherto
known are neotropical. However, the presence in the Indo-Malayan
region of forms allied to the neotropical fauna is not wholly without
parallel. The American and Indian tapirs are probably the best-
known examples. The well-known resemblance between the faunas
of eastern North America and eastern Asia is continued by a less
sharply defined series of related forms in the tropics of Central
America and southeastern Asia. This is shown in particular by
such well-marked snakes as Trimeresurus and Sibynophis, and by the
ophidian family Achrochordidae, which has a single Central American
representative (Nothopsis), and the family Aniliidae, which is
represented in tropical America by the well-known genus Anilius
(Ilysia of authors), and in southeastern Asia by Cylindrophis and
Anomalochilus. The same parallel is exhibited by numerous fresh-
water turtles of the East Indies and North and Central America.
The situation among amphibians is less clear, being obscured by
the presence of several world-wide genera, such as Rana and Bufo,
as dominant types.

Published figures and descriptions show that several species of
long-legged East Indian toads are suspiciously similar to borbonica
in external appearance. It is altogether possible that such species
as Bufo penangensis, B. cruentatus, and B. leptopus will be found on
dissection to be referable to the genus Cacophryne.

The necessity of referring Cacophryne to the Atelopodidae brings
up the question of the status of this family. As defined by Noble
(1931) it is a polyphyletic assemblage of convergent types. He
states (p. 505) that "the Brachycephalidae [= Atelopodidae] show
more clearly than any other family of Salientia the details of their
origin. Each subfamily has arisen from a different stock of bufonids,
but as all the ancestral stocks were bufonids residing in the same
general region, the Brachycephalidae may be considered a natural,
even though a composite family." This curious line of reasoning
leads to difficulties. By definition, a "composite" family is an incon-
ceivable anomaly, since a family is a group of related genera, derived
from a common ancestor, in the same sense that a genus is a group of
related species of common origin. Indeed, a few pages farther on
Noble reverses his view completely. In speaking of the hylid genera
Hylella and Nyctimystes he says: "But as these genera are poly-

1935 POSITION OF BUFO BORBONICA — DAVIS 91

phyletic assemblages scarcely distinct from Hyla, they are not recog-
nized here." (p. 508.)

The only possible view that is compatible with modern taxonomic
conceptions is that if, as Noble contends, the three "subfamilies"
Rhinodermatinae, Dendrobatinae, and Atelopodinae have each arisen
independently from different stocks, whether these stocks resided
in the same general region or not, and no matter how similar the
derived groups may appear to be, they must be accorded full family
status, or else absorbed in the parent family. The latter course
hardly seems indicated in this case, since each of the three groups
differs from the Leptodactylidae in one or more fundamental respects.
I propose, therefore, that the subfamilies Rhinodermatinae, Dendro-
batinae, and Atelopodinae be accorded full family status, forming,
together with the Bufonidae and the Leptodactylidae, the super-
family Bufonoidea.

Regarding the family relations of the new genus, Mr. Parker
writes me: "Comparison of the characters I give for the various
firmisternal groups puts it at once in the Atelopodidae. Concern-
ing this group I am still very uncertain, but B. borbonica seems to
me to bear exactly the same relation to Pedostibes as Didynamipus
does to Nectophryne."1 This alternative, that Cacophryne is still
a fourth independent derivative from the arciferal Bufonoidea,
seems to be negatived by its complete agreement in essential
characters with the South American genera. If the view suggested
by Parker were adopted, the natural assumption would be to look
upon the geographically close Pedostibes as the parent stock from
which Cacophryne has been derived. It is well known that the
firmisternal condition of the pectoral girdle has been assumed upon
numerous occasions by various salientians, and the firmisternal
pectoral girdle in Cacophryne would by no means rule out the arciferal
Pedostibes as the ancestral stock.

The morphology of the urogenital organs is still more significant.
All available evidence, as yet unpublished, indicates that Bidder's
organ, once developed, has persisted in all derived types of Bufonidae.
Closely related forms (e.g., Leptodactylus) have the elongated testes,
but never possess a Bidder's organ. In Cacophryne, however, not
only is Bidder's organ lacking, but the testes are of the oval form
typified by Rana. The derivation of Cacophryne from any bufonid
genus, in spite of the fact that it would greatly simplify the situation

1 Parker (1931, p. 1247) has shown that the firmisternal Didynamipua should
be regarded as independently derived from the arciferal Nectophryne.

92 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. XX

from the standpoint of geographical distribution, seems highly
improbable.

Cacophryne must be assumed to have originated from an unknown
leptodactylid stock when this was more extensively represented in
the northern hemisphere. This genus then takes its place in the
restricted family Atelopodidae, which can thus no longer be regarded
as an endemic South American family.

REFERENCES

BOULENGER, G. A.

1882. Catalogue of the Batrachia Salientia s. Ecaudata in the Collection of the
British Museum. London, Brit. Mus., xvi + 495 pp.

COPE, E. D.

1867. On the Families of the Raniform Anura. Jour. Acad. Nat. Sci. Phila.,
6, pp. 189-206.

KAMPEN, P. N. VAN

1911. Javanische Amphibien, gesammelt von Edw. Jacobson. Notes, Leyden

Mus., 34, 75-79 pp.
1923. The Amphibia of the Indo-Australian Archipelago. Leiden, E. J. Brill,

xii + 304 pp.

NOBLE, G. K.

1931. The Biology of the Amphibia. New York, McGraw-Hill, xiii+ 577 pp.
PARKER, H. W.
1931. Parallel Modifications in the Skeleton of the Amphibia. Arch. Zool.

Ital., 16, pp. 1239-1248.

1934. A Monograph of the Frogs of the Family Microhylidae. London,
Brit. Mus., viii + 208 pp.

PETERS, W.

1863. Uber verschiedene Batrachier, namentlich iiber die Original-exemplare
der von Schneider und Wiegmann beschriebenen Arten des Zoologischen
Museums zu Berlin. Monatsber. Akad. Wiss. Berlin, 1863, pp. 78-82.

SCHLEGEL, H.

1826a. Erpetologische Nachrichten. Isis, 20, pp. 282-294.
1826b. Notice sur 1'erpetologie de Tile de Java; par M. Boie. Bull. Sci. Nat.
Fe>ussac, 9, pp. 233-240.

SMITH, M. A.

1925. Contributions to the Herpetology of Borneo. Sarawak Mus. Jour., 3,
pp. 15-34.

1930. The Reptilia and Amphibia of the Malay Peninsula. Bull. Raffles Mus.,
3, xviii+149 pp.

TSCHUDI, J. J.

1839. Classification der Batrachier mit Beruchsichtigung der fossilen Thiere
dieser Abtheilung der Reptilien. Mem. Sci. Nat. Neuchatel, 2, 1-99 pp.

MAY 3 1 1935

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