A new snake from Arabia

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UNIVERSITY OF ILLINCIS
ZOOLOGICAL SERIES

OF
FIELD MUSEUM OF NATURAL HISTORY

Volume XX CHICAGO, DECEMBER 11, 1933 Pages 9-10

A NEW SNAKE FROM ARABIA

BY KARL P. SCHMIDT

ASSISTANT CURATOR OF AMPHIBIANS AND REPTILES

A small collection of lizards and snakes made by Mr. A. R. M.
Rickards, of Aden, southern Arabia, in the Aden area in 1932 has
been presented to Field Museum by Mr. Henry Field, whose
enthusiastic interest in southwestern Asia has already brought
several other accessions of zoological specimens from this general
region. The interesting south Arabian reptilian fauna has not
previously been represented in Field Museum's collections. That
our knowledge of the reptilian fauna of this part of the world is
still far from complete is well shown by the numerous new forms
described in recent papers, by Mr. H. W. Parker on collections
from southeastern Arabia, and by Mr. G. Scortecci on reptiles from
Yemen. It is nevertheless surprising that Mr. Rickard's collection
contains a new species of snake, referable to the genus Rhyncho-
calamus, which has hitherto been known only from R. melanocephalus
in northwestern Arabia, Palestine, Syria, and Lower Egypt. The
description of this new form follows:

Rhynchocalamus arabicus sp. nov.

Type from Aden, Arabia. No. 18,219 Field Museum of Natural
History. Female. Collected 1932 by A. R. M. Rickards.

Diagnosis. — Closely allied to Rhynchocalamus melanocephalus
(Jan), with which it agrees in its reduced maxillary dentition and
greatly elongate posterior solid fang, and from which it is distin-
guished by its uniform dark color, much wider frontal shield, and
higher number of ventral plates and subcaudals.

Description of type. — Body elongate, slender; head only slightly
distinct from neck; ventrals distinctly angulate; pupil round; rostral
slightly offset from the adjacent scales, extending backward on the
upper surface of the head nearly halfway to the frontal; internasal
suture half as long as that between the pref rentals; frontal propor-
tionately very wide, nearly as wide as long, about as long as its

No. 320

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

distance from the tip of the snout; supraoculars narrow, narrower
anteriorly than posteriorly; parietals large; nasal undivided; a
subquadrate loreal slightly longer than high; one preocular and one
postocular; temporals 1-1 on each side; upper labials four on the
left and five on the right side, with a partial suture in the elongate
fifth labial, and a suggestion of one in the enlarged second labial on
the left side, indicating that the normal labial formula may be 6-6;
lower labials 8-8, the first pair broadly in contact behind the mental;
a large pair of anterior chin-shields; posterior chin-shields scarcely
differentiated from the gulars; dorsal scales in fifteen rows except
on the neck, where there are twenty-one rows at the first ventral,
dropping to fifteen at the ninth; ventral plates 240; anal divided;
subcaudals 81, the last five, including the terminal one, entire.

General color black, the scales faintly and narrowly outlined
with light.

Measurements. — Total length 278 mm., tail 49 mm.

Remarks.— This species is plainly the representative in south-
western Arabia of the Syrian R. melanocephalus. The very different
shape of the frontal, with the combination of additional characters,
appears to indicate that it is a fully distinct species. The distinctness
of the genus Rhynchocalamus from the East Indian and Indian
Oligodon, with which it was combined by Boulenger, has been
maintained by Barbour (Proc. New England Zool. Club, 5, p. 91,
1914). The genus is much more satisfactorily established by the
discovery of a second species, which fails in any way to bridge the
gap between R. melanocephalus and the Indian species of Oligodon,
and is directly allied to the former.

F

UNIVERSITY OF ILLINOIS-URBANA