UiMlVtRSiTY OF
ILLINOIS LIBRARY
URBANA CHAMPAIGN
BIOLOGY

1

FIELDIANA

Zoology

Published by Field Museum of Natural History

Volume 72, No. 2 December 16, 1977

Amphisbaena medemi, An Interesting New Species
from Colombia ( Amphisbaenia, Reptilia),

with a Key to the
Amphisbaenians of the Americas

CARL CANS

DIVISION OF BIOLOGICAL SCIENCES
UNIVERSITY OF MICHIGAN, ANN ARBOR

AND

SANDRA MATHERS

DIVISION OF BIOLOGICAL SCIENCES
UNIVERSITY OF MICHIGAN, ANN ARBOR

SUMMARY

Amphisbaena medemi, new species, is a small amphisbaenian from extreme north-
ern South America. The species belongs to the grouping of small, four-pored animals
and is suggestive of a stage intermediate between species from the mainland of
South America and from the Antilles. The paper includes a key to all recognized
forms of American amphisbaenians.

The amphisbaenians of northern South America (cf. Cans, 1967)
fall into two obvious groups. The first includes two large species,
Amphisbaena alba and Amphisbaena fuliginosa, wide-ranging
forms that occur across the Amazon basin and far to the south ( cf .
Cans, 1962a; Vanzolini, 1951). The second includes a series of five
much smaller species, all with relatively restricted ranges, perhaps
parapatric but certainly included within the ranges of the larger
forms. The character states of these small forms suggest some di-
versity; however, they all share such characteristics as fewer than
18 dorsal and fewer than 20 ventral segments to a mid-body annu-
lus, a bluntly-rounded head with relatively large and regular shields
and body annuli between 205 and 250. Four of the five species show
four precloacal pores. If the poorly characterized Amphisbaena

US ISSN 0015-0754

Publication 1271 l<^ 21 J J\N 2 7 1978

. .,

V\ J

22 FIELDIANA: ZOOLOGY, VOLUME 72

stejnegeri (known from two damaged specimens) is eliminated, the
clustering of character states becomes even more marked.

The assemblage is perhaps most interesting because one of its
members, Amphisbaena gracilis Stauch, has been shown to repre-
sent those conditions among all mainland forms that appear closest
to the character states of the nine species of Amphisbaena inhabit-
ing the Greater Antilles and adjacent islands (Sponga and Gans,
1971). Consequently, it is of some interest here to report on the dis-
covery of yet another small mainland species that not only fits into
the continental grouping but shows further affinity to the Antillean
populations.

We are grateful to Mr. Hymen Marx and Dr. Harold Voris, Field
Museum of Natural History (FMNH), for making these specimens
available for study and take pleasure in naming this new form after
Dr. Fred Medem, collector of most of the specimens, in recognition
of his substantial contribution to our knowledge of the herpetofauna
of Colombia. Supported by National Science Foundation grant
BMS 71 01380.

Amphisbaena medemi new species

Holotype. FMNH 165245, taken between 1 and 10 December
1965 at Cienaga de Amajehuevo, Canal, Depto. Atlantico, Colombia
by Federico Medem H.

Paratypes.-FMNH. 165243-165244, 165246-165247, taken be-
tween 1 and 10 December 1964 with the holotype, FMNH 165248-
165250, taken on 15 January 1965 by C. A. Velasquez, and FMNH
165251-165257 taken on 31 January 1965 by F. Medem; all from the
same locality.

Diagnosis. A small to medium-sized form of Amphisbaena with
the nasals totally separated or reduced to medial point contact by
the ascending rostral which generally contacts the frontals. Speci-
mens often have azygous fusion of postocular and parietal head
scales; three equally sized supralabials ; one medium, one large, and
one small infralabial on each side; two postgenial and no postmalar
rows of chin shields. There are 230-235 body annuli; 17-18 caudal
annuli with the autotomy constriction falling on the fifth to seventh
postcloacal annulus; 16 dorsal and 18 ventral segments per midbody
annulus; and four large circular precloacal pores in both sexes. The
specimens are brown dorsally, fading to a lighter color ventrally.
The color is densest in the rectangular centers of each segment, with
the dark area decreasing along the sides and dropping out by seg-

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23

FIG. 2. Amphisbaena medemi. Dorsal (top), lateral (middle), and ventral (bottom)
views of FMNH 165245 show segment arrangement. The line equals 1 mm. to scale.
(Don Luce, del.).

24

FIG. 3. Amphisbaena medemi. Dorsal, lateral, and ventral views of FMNH 165245
to show pigmentation, and the sculpturing of the surface.

25

FlG. 4. Amphisbaena medemi. Details to show variation. Frontal views of FMNH
165253 (a), and 165249 (b) to show extremes in the kinds of contact between rostral
tip and frontals. Views of the nuchal region of FMNH 165244 (c) showing fusion of
postocular to parietal on the right side and of FMNH 165256 (d) showing bilateral
fusion. (Don Luce, del.). The line equals 1mm. to scale.

26

CANS & MATHER: AMPHISBAENIANS

27

FIG. 5. Amphisbaena medemi. Dorsal view (left), lateral view (middle), and ven-
tral view (right) of FMNH 165243 at mid-body to show proportions and pigmen-
tations of segments.

ments in the neck and caudal regions. Many specimens show a light
nuchal band.

Description. Figures 2 through 7 show aspects of segmentation,
pigmentation and body proportions. Figure 8 presents a scatter dia-
gram of tail lengths versus snout-vent lengths. The raw data for the
type series are given in Table 1.

This is a small to medium-sized species of Amphisbaena, showing
a brownish dorsal and a lighter ventral coloration. The tip of the
snout and the nuchal region tend to be lightened, while the dorsal,
lateral, and posterior surfaces of the tail are densely pigmented. The
lateral limits of pigmentation extend onto the ventral surface of the
tail so that only the medial two to four rows of segments are light-
ened. The intersegmental and interannular sutures are always
lighter than the scale centers. Rostral, nasals, and superlabials as
well as the chin shields tend to be unpigmented. Two or three annuli
between the second and seventh may be faded or may lack pigmen-
tation producing a light band across the nuchal region.

The dorsal surface is more or less uniformly pigmented with only
slight emphasis of the segmental centers. The two middorsal rows
of segments are significantly darkened. One or two rows below the

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CANS & MATHER: AMPHISBAENIANS 29

lateral sulcus the pigmentation becomes restricted to the segmental
centers and these may become very small and faint by the fifth or
sixth ventral row from each side. The three or four annuli anterior to
the cloaca and the midventral segments of the caudal annuli show
checkerboarding with the pigmentation appearing to drop sharply
and often asymmetrically on individual segments.

The head segmentation is characterized by a caudad projection of
the dorsal tip of the rostral which partially or totally separates the
nasals from medial contact and in some specimens inserts briefly
between the pref rentals, and by the generally azygous fusion of
parietal and postocular head scales; yet lacks other major fusions.
The head is dorsoventrally compressed; the slightly elongated
snout is dorsally arched but is of a horizontally oval cross-section.
The rostral tip extends beyond the lower jaw and the temporal
bulges noticeably posterior to the eye. There is some indication of
nuchal constriction and slight reduction of the diameter of the nu-
chal region. The trunk is approximately the same diameter along its
length and is compressed dorso-ventrally representing at midbody a
horizontally oval cross-section.

The rostral is visible from above, slightly larger than the first su-
pralabial, and of the same area as the nasals. Pairs of separated
nasals, large prefrontals, medium-sized frontals, and smaller, quad-
rangular to pentagonal parietals form a sequence along the dorsal
surface of the head. The posterior tips of the frontals insert along
the anterior suture between the parietals. Only four specimens have
discrete parietals, in six that of the right side is fused to the en-
larged postocular, in one fusion is on the left side and two show both
sides fused. The diamond-shaped oculars are in anterior contact
with the third supralabials and the large postocular. Each of three
subequal supralabials is slightly larger than the ocular. The post-
supralabial (just posterior to the angulus oris) abuts dorsally on the
very large first temporal (which may be in point contact with the
ocular). The postsupralabials, temporals, postoculars, and frontals
apparently comprise the dorsal segments of the first body annulus.
The four middorsal segments of the second body annulus are irregu-
larly enlarged and lie posterior to the parietals, which thus seem to
represent a medially intercalated pair of segments. The eye is clear-
ly apparent.

The mental is slightly narrower than the rostral, its area equiva-
lent to that of the first infralabials which are followed by large sec-

FIG. 6. Amphisbaena medemi. Ventral view of cloaca and tail of FMNH 165257
to show segmental proportions. The line equals 1 mm. to scale. ( Don Luce, del. ).

30

FIG. 7. Amphisbaena medemi. Dorsal and ventral views of the tail of FMNH
165243 to show pigmentation and overall proportions.

31

32 FIELDIANA: ZOOLOGY, VOLUME 72

ond infralabials and smaller rectangular third infralabials. The
ovate, posteriorly triangular postmental is in straight contact with
the mental, in broad contact with the first and second infralabials,
flanked by the elongate elements of the first, and in narrow contact
with the central element of the second postgenial row. The malars
are roughly as wide as long, in medial contact with the third infra-
labials and broadly contact the second infralabials. The malars flank
the two rows of postgenials, the interrupted first containing two
and the second containing three to five segments. The second row of
postgenials tends to be irregular and its segments may fuse with
those of the first body annulus. There is no postmalar row, nor are
the immediate postmalar segments enlarged by fusion.

Dorsally the first body annulus includes one to two small seg-
ments posterior to the third supralabial, the temporal, the postocu-
lar, and the frontals. The dorsal segments of the nuchal region are
enlarged and the corresponding ventral segments reduced. The dor-
sal segments along the trunk consistently decrease slightly in size
from the nuchal region towards the cloacal zone and onto the tail.

There are 230-235 body annuli from the back of the third infrala-
bial up to and including the pore-bearing precloacal. Irregularity of
the segmentation or dorsal half-annuli are rare. A midbody annulus
contains 14 to 16 (generally 16) dorsal and 16 to 18 (generally 18)
ventral segments.

The cloacal region is characterized by four large, circular preclo-
acal pores, six to eight precloacal segments, 12 to 17 postcloacal
segments and three to five lateral rows. There are 17 to 18 caudal
annuli up to the smooth caudal cap, with the autotomy annulus fal-
ling on the fifth to seventh postcloacal annulus. No specimens show
autotomized tails or healed scars. Segments bearing rectangularly
pigmented centers extend further ventrally on the autotomy annulus
than on other caudal annuli. The tail is horizontally oval in section
at its base, then reaches a vertically oval section, with an indented
ventral surface in the terminal third. For the last three annuli it
shows a sharp bilateral flattening so that it terminates in a blunt
vertical keel.

The lateral sulci begin after approximately the 45th body annulus
and continue up to the level of the cloaca. These sulci are poorly de-
fined and narrower than one bordering segment. There is no obvious
dorsal sulcus. Lateral and ventral sulcal regions are characterized
by slight indentations of the trunk.

CANS & MATHER: AMPHISBAENIANS

33

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Snout-vent length in cm

FIG. 8. Amphisbaena medemi. Scatter diagram of tail lengths vs. snout-vent
lengths for the available specimens.

The middorsal segments of the midbody annulus are approxi-
mately two times as long as wide. The ventral segments are approx-
imately IVa times as wide as long.

Range. Known from the type locality only.

Ecology. The animals were taken during the construction of the
fish cultural station of Inderena at the Laguna de Amajahuevo (De-
partamento Atlantico) which lies on the shore of the Canal del Dique
close to the village San Cristobal ( Departamento Bolivar). The vil-
lage is ! 1 /2 hours by boat from the town of Soplaviento (Departa-
mento Bolivar; 53km. from Cartagena) and lies between the lagoon
(about l!/2 hectares) and the canal. All specimens, as well as some
Leptotyphlops and Bachia, were collected at depths of approxi-
mately 60 cm. to 1 m. in ditches easily excavated for foundations in

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CANS & MATHER: AMPHISBAENIANS 35

the dry and sandy soil. No rain fell during the period of collection.
Generally December is the end of the rainy season at this locality.

The site of the excavation was unshaded by large trees, but cov-
ered by pasture and scrubs. The mean temperature of the region is
about 25-35 C. in the shade. Locals indicate that the general region
sometimes floods during the rainy season.

Etymology. Named after Dr. Federico Medem M., who collected
the specimens, in recognition of his contributions to the biology of
South American reptiles. Dr. Medem informs us that the animals
are locally referred to as "tatacoas" or "ciegas."

DISCUSSION

Table 2 (based upon the reports of Gans, 1962b, 1963, 1964; Gans
and Alexander, 1962; Hoogmoed, 1973; Sponga and Gans, 1971;
Thomas, 1965, 1966) summarizes the character states of the various
small amphisbaenians of northern South America and the Antilles.
It shows that the character states of Amphisbaena medemi are very
close to those of A. fenestrata in body annuli, number of segments
to a mid-body annulus, rostro-frontal contact, and number of preclo-
acal pores. They differ in number of caudal annuli, in the tendency
of A. fenestrata to have a medial sulcus at least posteriorly, as well
as a postmalar row, and of A. medemi to have a longer tail and
caudal autonomy. A. fenestrata shows a checkerboard pigmentation
rather than the gradual fading of pigmentation that characterizes
medemi. While the similarity to A. fenestrata is considerable, it is
only an expression of a general similarity between such forms as A.
xera and A. caeca, on the one hand, and of A. medemi and A. gra-
cilis, on the other. A. medemi is similar to the Antillean form as it is
the only form of the northern mainland that has fewer dorsal than

Key to Table 2 opposite:

1. Key to abbreviations: Box, rectangular pigmentation in center of each seg-
ment; CB, checkerboard dropping out of pigment; Fad. pigment fading and grad-
ually from dorsal to ventral along sides of trunk; Unif ., uniform pigmentation across
entire surface of segments; X, first, second, and third genial or malar row present.

2. Key to Special States column. 1, Ocular fused to second supralabial; 2, extra
dorsal half annuli; 3, rostral and nasals fused; 4, rostral and frontals in contact;
5, caudal tuberculation; 6, rostral and frontals generally in contact; 7, body seg-
ments tuberculate; 8, mental and post mental fused.

36 FIELDIANA: ZOOLOGY, VOLUME 72

ventral segments to a midbody annulus. The various kinds of fu-
sions (listed under special states) would seem to represent indepen-
dent events rather than a sequence.

We must again echo Sponga and Cans (1971) in deferring conclu-
sions until additional and preferably internal character states of the
new form have been compared with those of other species. This
should presumably proceed in parallel with such analysis of the
small amphisbaenians now assigned to other genera.

The new form and the results of some other recent papers ( Sponga
and Gans, 1971; Vanzolini, 1971; Stimson, 1972; Gans and Diefen-
bach, 1972; Hoogmoed, 1973; Gans, 1974) permit amplification of
the key to the American Amphisbaenia (Gans and Diefenbach,
1970).

KEY TO THE AMERICAN AMPHISBAENIA

[The following key to the Recent amphisbaenians of the Americas
attempts to characterize the forms presently recognized on the basis
of external characteristics. No effort has been expended to make the
key natural but the most obvious and clearly apparent characteris-
tics have always been emphasized. As certain characteristics such
as pigmentation may occasionally be absent, and many species
demonstrate caudal autotomy, we have avoided use of characteris-
tics involving these and have provided multiple criteria for as many
couplets as possible in order to facilitate identification. The key
omits Amphisbaena polygrammica as being insufficiently charac-
terized to permit diagnosis.]

Characterization of American Amphisbaenia: Body cylindrical, sometimes a ten-
dency toward slight dorsoventral or lateral compression. Temporal musculature
may be swollen and followed by a slight nuchal constriction in adults. Head often
not differentiated from body in juveniles. Anterior third of body often slightly thick-
ened but rarely with any significant diametric reduction between head and vent.
Tail always less than 20 percent of body length. Skin annulated with dorsal and ven-
tral half-annuli meeting at, and sometimes continuous across, a lateral groove on
each side which starts in the first third of the body and runs to the vent.

Head may be rounded, pointed, spatulate or keel-shaped with or without keratin-
ization. Mouth depressed, edges of lip inserted within head. Eye small, beneath skin,
clearly visible in fresh specimens but with pigments sometimes bleaching out in
preservative.

Precloacal pores in a single row present or absent with their expression often ex-
hibiting sexual dimorphism. Tail often with autotomy constriction at which it may
break and heal into a conical stump without regeneration. Distal tip of original tail
occasionally with keels, nobs or other modifications.

CANS & MATHER: AMPHISBAENIANS 37

1. Two well-developed forelimbs, but no hindlimbs (head large and bluntly
rounded; an enlarged azygous prefrontal; discrete nasals, preoculars and
supra oculars; dorsal and ventral half-annuli poorly aligned along lateral
sulci, with dorsal number 50 per cent higher; precloacal pores in two series,

widely separated) (Bipes ) 10

No external evidence of fore or hindlimbs 2

2. Snout shovel-shaped with a more or less obvious horizontal edge (shields

of pectoral region often markedly irregular; no precloacal pores, tail

short, generally lacking an autotomy plane) 3

Head rounded, pointed or vertically keeled 5

3. Rostral folded around center of horizontal edge; three pairs of regular

paired shields, but no azygous shields, follow it along midline of the
head; tail very short and blunt but with well marked narrow autotomy

constriction Aulura anomala

Rostral excluded from center of horizontal edge; one or more azygous
shields along midline on dorsal surface of head; tail lacking autotomy
constriction 4

4. Tip of snout broadly rounded; nostrils in discrete nasals; at least three

enlarged azygous shields on midline of head; caudal tip dorsoventrally

flattened, its dorsal surface covered with multiple small tubercles

Rhineura floridana

Tip of snout narrowly rounded or pointed; nostrils in a fused rostro-nasal

shield; caudal tip short and bluntly rounded without tuberculation

(Leposternon) 15

5. Prefrontal azygous (flanked laterally by a postnasal supraocular segment;

a single row of medially interrupted precloacal pores; tail short, round-
ed, lacking autotomy plane; pigmentation pattern involving spots and

blotches, more or less independent of the segmental arrangement)

(Cadea) 14
Prefrontals paired 6

6. Head keel-shaped; rostral very much enlarged, and ascending over the

face, keeping the nasals, prefrontals, and sometimes the frontals from
contact (keel sometimes keratinized; distal tip of tail may bear vertical

ridge; tail lacking autotomy plane) 7

Head pointed or rounded, otherwise slightly compressed laterally; rostrals
not separating frontals and prefrontals 9

7. Frontals in broad contact on midline ; rostral longer than high with a blunt

vertical keel (rarely keratinized); (two precloacal pores separated by a

median hiatus and three supralabials ; 259-281 body annuli)

Mesobaena huebneri

Frontals (and prefrontals) in point contact or separated by ascending
process of rostral; rostral higher than long with a sharp vertical keel;
(four precloacal pores in a continuous series or two supralabials) 8

8. Postmental larger than malar; three supralabials ; 214-249 body annuli (no

supernumeraries); four precloacal pores in an uninterrupted row

Anops kingi

38 FIELDIANA: ZOOLOGY, VOLUME 72

Postmental not larger than malar; two supralabials; 358-372 body annuli
(including supernumeraries); two precloacal pores in a medially inter-
rupted row Anops bilabialatus

9. Head with marked vertical compression; rostral in broad contact or ex-
cluded from contact with enlarged prefrontals; neither parietals nor
occipital segments enlarged; two medially-separated short rows of pre-
cloacal pores (Bronia) 10

Head generally rounded, pointed or only faintly compressed; rostral with-
out or with only narrow median contact with prefrontals, unless they
have fused with nasals; a variable number of round or oval precloacal
pores in a single row of procloacal segments without a major hiatus ....

(Amphisbaena) 20

10. Nasal segments do not contact each other; 213-229 body annuli; 18-21/18-

21 midbody segments Bronia brasiliana

Nasal segments contact each other; 281 body annuli; 28/24 midbody seg-
ments Bronia kraoh

11. Six to eight precloacal pores; three to five digits per hand 12

Two wide precloacal pores ; five digits per hand Bipes biporus

12. Three digits per hand; 142 ventral and 169 dorsal half annuli; 32-35 dorsal

and 30-38 ventral segments to a midbody annulus .... Bipes tridactylus
Four to five digits per hand; more than 148 ventral (and near 200 dorsal
half annuli; apparently lower numbers of segments to a midbody annu-
lus) 13

13. Most specimens with fewer than 159 half annuli; always fewer than 201

dorsal half annuli Bipes c. canaliculatus

Most specimens with more than 165 ventral half -annuli; always more than
215 dorsal half annuli Bipes canaliculatus multiannulatus

14. Body annuli 175-218 (counted on ventral surface), caudal annuli 10-14,

segments in a midbody annulus 25-33, snout rounded, blunt

Cadea blanoides

Body annuli 274-320 (counted on ventral surface), caudal annuli 12-17,
segments in a midbody annulus 32-39, snout domed, laterally com-
pressed Cadea paliro strata

15. Only two rows of enlarged scales visible in dorsal view atop the head ( the

first of these the rostro-nasal, the second the azygous which may or may
not be followed by a fringe of very much smaller segments in the occipi-
tal region); suture pattern simple; pectoral region covered with very

large geometrically regular shields 16

Three or more rows of enlarged shields atop the head, suture pattern often
complex; pectoral region complexly divided or not 17

16. Rostro-nasal followed by an enormous azygous shield which covers nearly

the entire dorsal surface of the head, narrowly fringed posteriorly by a
single row of very much smaller segments; head shield strongly keratin-

ized; mental and postmen tal discrete; 253-305 postpectoral annuli

L. scutigerum

CANS & MATHER: AMPHISBAENIANS 39

Rostro-nasal followed by a very large azygous, flanked on each side by tri-
angular pref rentals and small temporals; headshields not significantly
keratinized; a single mental-postmental segment; 378 postpectoral
annuli. L. octostegum

17. A single, very small first supralabial followed by a large second and a

small third supralabial 18

A very large first supralabial followed by a smaller second supralabial. . 19

18. Azygous shield in contact with rostro-nasal; frontals and medial tempor-

als much larger than the azygous, longer than wide and arranged in a
characteristic linear grouping; infraocular absent; a small first followed
by a large second infralabial; pectoral shields in a regular arrangement
of large shields reminding of an hourglass; dorsal number of postpector-
al annuli generally equal to ventral, rarely up to 10 greater than; adults
of medium size ( snout-vent length equals 205-432 mm. ) . . L. polystegum

Azygous shield separated from contact with the rostro-nasal by a wide
suture between pref rentals; frontals about as wide as long, not sig-
nificantly larger than the azygous, temporals much smaller, infraocular
generally present; a very large first infralabial; pectoral segments only
slightly enlarged, rounded sometimes with irregular longitudinal fu-
sions; dorsal number of postpectoral annuli always five to 25 higher
than ventral number; adults very large (snout-vent length equals 285-
600 mm.) L. infraorbitale

19. Azyous always distinctly delineated; pectoral region covered by three to

four pairs of elongated regularly arranged shields which may fuse except
for the midline; number of dorsal and ventral postpectoral annuli more

or less equal; 242 to 265 postpectoral annuli L. wuchereri

Azyous often fused in various ways with adjacent head shields; a medial
pair of elongate pectoral shields with other modified, possibly enlarged
shields radiating out from these anteriorly; always significantly (5-25)
more dorsal than ventral postpectoral annuli with the increase greater in
the second, third, and fourth fifths of the trunk (177-242 postpectoral
annuli) L. microcephalum

20. Nasals entirely separated from medial contact by posterior tip of ros-

tral 21

Nasals in contact at midline 22

21. Body darker brown dorsally, lighter ventrally by checkerboarding, tail

faintly conical, pointed, with 12 to 14 annuli, lacking autotomy, malar

row present A. fenestrata

Body darker brown dorsally, lightened ventrally by reduction of seg-
mental centers. Tail rounded, with slight distal pinching, with 17 to 18
caudal annuli and an autonomy annulus at the 5th to 7th; no malar
row A. medemi

22. With constant and characteristic fusion of head shields 23

Without major fusions of head shields (rostral, nasals, pref rentals, fron-
tals, supralabials and oculars always discrete) 26

40 FIELDIANA: ZOOLOGY, VOLUME 72

23. Mental and postmental fused (243-247 body annuli; 6 precloacal pores;

33-39 segments per midbody annulus; nasals larger than prefrontals;

caudal autotomy near 9th annulus) A. stejnegeri

Mental and postmental discrete 24

24. Second supralabial and ocular fused; rostral and nasals discrete (199-

240 body annuli; 10-18 caudal annuli; 4-6 precloacal pores; 26-34 seg-
ments per midbody annulus; no postmalar row) (A. cubana) 25

Second supralabial and ocular discrete; rostral and nasals fused (209-
243 body annuli; 17-22 caudal annuli; 4-9 precloacal pores; no postmalar
row) A. manni

25. 199-218 body annuli; 10-14 caudal annuli, with caudal autotomy

A. c. cubana

226-240 body annuli; 14-18 caudal annuli, no caudal autotomy

A. cubana barbouri

26. Very large and thick (adults near 40-50 cm. in length, more than 1.5 cm.

in diameter); more than 65 segments to a midbody annulus; with prom-
inent temporal; tail of same diameter as the trunk; lacking caudal
autotomy; terminal caudal annuli weakly delimited; 4-10 precloacal

pores A. alba

Medium to large, generally more slender; between 48 and 65 segments to
a midbody annulus; head acutely pointed, to a spatulate rostral tip;
caudal autotomy lacking or if present the anterior body half annuli
meet at the middorsal line in a posteriorly open herringbone pattern

(A. angustifrons) 27

Small to medium-sized, adults less than 35 cm. long, less than 1 cm. in
diameter; fewer than 48 segments to a midbody annulus; lacking caudal
autotomy (diagnosis for A. miringoera based on illustration in Van-
zolini, 1971) 28

Small to large, generally more slender; fewer than 85 segments to a mid-
body annulus; head variously rounded or pointed, anterior body annuli
crossing middorsal line in a more or less straight line; caudal autotomy
annulus obviously present 38

27. Adults 28 to 41 cm. in snout-vent length; with body diameter 11 mm. or

greater; generally 205-218 body annuli; annuli of the postnuchal region
cross the back at right angles; no caudal autotmy; 13-19 caudal annuli

A. a. angustifrons

Adults less than 30 cm. in snout-vent length; with body diameter 11 mm.
or less; generally 233-282 (rarely 210) body annuli ; lateral half-annuli
of the nuchal region typically meet in a posteriorly open angle pre-
senting a "herringbone" pattern; autotomy between 5th and 9th caudal
annulus; 18-21 caudal annuli A. angustifrons plumbea

28. More than 238 body annuli 29

Fewer than 232 body annuli 33

29. More than 40 segments per midbody annulus A. o. occidentalis

Fewer than 41 segments per midbody annulus 30

CANS & MATHER: AMPHISBAENIANS 41

30. Fewer than 20 caudal annuli 31

More than 20 (22-24) caudal annuli; (250-262 body annuli; 12-15 ventral

segments to a midbody annulus; two precloacal pores) . . . A. miringoera

31. 14-16 caudal annuli; tail round ended; body cylindrical; head not smaller

than trunk; second supralabials by far larger than 1st and 3rd supra-
labials A. bakeri

17-19 caudal annuli; tail clearly vertically keeled; body widened after nu-
chal region; head very small relative to the trunk; second supralabials
not markedly larger than 1st and 3rd supralabials 32

32. 250-266 body annuli; 16 ventral segments to a midbody annulus

A. s. steindachneri

239-245 body annuli; generally more than 16 ventral segments to a mid-
body annulus A. s. borelli

33. Tail sharply conical, tip only one-half diameter of base; very distinct

nuchal constriction ( fewer than 193 body annuli) ; snout pointed

A. ridleyi

Tail cylindrical; without conspicuous nuchal constriction (185 or more
body annuli); snout broad 34

34. Tail with marked vertical keel distally (26-31 segments per midbody

annulus) A. bahiana

Tail with round end (29-42 segments per midbody annulus) 35

35. Postmental markedly larger than mental; postmalar row absent 36

Postmen tal shield around the same size as mental; postmalar row pre-
sent A. g. gonavensis

36. Two precloacal pores; 213-231 body annuli; second supralabial faintly

larger than first A. dubia

Four precloacal pores; 185-219 body annuli; second supralabial markedly
larger than first 37

37. Second row of postgenials with four or more shields; 9-14 caudal annuli

A. i. innocens

Second row of postgenials with four shields; 18-19 caudal annuli

A. innocens caudalis

38. Two supralabials and three or fewer infralabials 39

More than two supralabials and more than two infralabials 40

39. 204-211 body annuli; 22-26 segments per midbody annulus; postoculars

larger than prefrontals but smaller than parietals; two infralabials;
four round precloacal pores; autotomy at the fourth to sixth of 23-25

caudal annuli; uniform medium brown, with little counter shading

A. slevini

200-231 body annuli; 24-34 segments per midbody annulus; postoculars
smaller than parietals which are smaller than prefrontals; IVi infralabi-
als; four oval precloacal pores; autotomy at the 7th to 14th of 28-31
caudal annuli; uniform dark brown dorsally, generally light ventrally . . .

A. vanzolinii

42 FIELDIANA: ZOOLOGY, VOLUME 72

224-248 body annuli: 28-32 segments per midbody annulus; postocular
smaller than parietals which are smaller than pref rentals; 2!/2 to three
inf ralabials ; four large oval cloacal pores, autotomy at 6th to 7th of
21-22 caudal annuli; uniformly very dark brown dor sally and ventrally

A. graciUs

40. Without postmalar row 41

Postmalar row present 48

41. Two precloacal pores 42

Four or more precloacal pores 45

42. Fewer than 182 body annuli 43

More than 202 body annuli 44

43. Fewer than 162 body annuli; 24-28 segments per midbody annulus

A. neglecta

More than 161 (179-181) body annuli; 20-24 segments per midbody an-
nulus A. silvestrii

44. 203-220 body annuli; precloacal pores large and oval; nasals as large as or

larger than pref rentals; parietals as large as or larger than frontals;

tip of tail round A. mitchelli

240-265 body annuli; precloacal pores round or faintly oval; nasals smaller
than prefrontals; parietals never larger than frontals; tip of tail with
vertical keel A. roberti

45. Postmental shield markedly longer and of larger area than mental 46

Postmental shield faintly larger, same size as, or smaller than mental

47

46. 225-234 body annuli; 10-16 caudal annuli; 5th to 7th caudal annulus

narrowed into autotomy constriction; first supralabial markedly smaller
than third A. xera

231-245 body annuli; 19-22 caudal annuli; 7th to 8th caudal annulus nar-
rowed into autotomy constriction; first supralabial around the same
size as third ( total length of adults, around 12 cm. ) A. carvalhoi

47. Fewer than 219 body annuli; 16-19 caudal annuli; 28-36 segments per mid-

body annulus; no distinct nuchal constriction; tail with pigmentation

pattern as trunk A. pericensis

222-226 body annuli; 19-24 caudal annuli; 26 segments per midbody an-
nulus; very distinct nuchal constriction; tail more darkly pigmented
than body A. nigricauda

48. More than 54 segments per midbody annulus; head clearly narrower

than body (acutely pointed) A. camura

Fewer than 56 segments per midbody annulus; head not markedly smaller
than trunk 49

49. More than four precloacal pores 50

Fewer than five precloacal pores 53

50. More than 10 precloacal pores; head and body to sixth annulus lacking

pigment A. leucocephala

CANS & MATHER: AMPHISBAENIANS 43

Fewer than 11 precloacal pores; head with same pattern of pigmentation
as body 51

51. Nasals larger than prefrontals; conspicuous checkered pattern of colora-

tion; third supralabial often split; suture between mental and first

infralabial sometimes fused A. fuliginosa

Nasals smaller than prefrontals; without conspicuous checkered pattern;
without splitting of third supralabial; suture between mental and first
infralabial distinct 52

52. Parietals of same size or larger than f rentals; no preocular shields; pig-

mentation of anterior part of body segments only; tail distinctly seg-
mented to tip A. mertensi

Parietals never larger than frontals; preocular shields (split off second
supralabial) often present; temporal bulges; tail relatively blunt with-
out distinct segmentation until tip (bulging temporal region; uniform
brown, ventral fading) A. pretrei

53. More than 260 body annuli A. occidentalis townsendi

Fewer than 261 body annuli 54

54. Medium to large-sized, with more than 211 body annuli and four sup-

ralabials A. vermicularis

Small, with fewer than 200 (196) body annuli and four supralabials ; (30

caudal annuli with autotomy on the llth) A. tragorrhectes

Medium to large-sized, with three or fewer supralabials, and small to

medium sized animals, with fewer than 219 body annuli and three or

four supralabials 55

55. Triangular mental and lozenge-shaped postmental meet in point contact;

also point contact between first parietals; head elongate and flattened

A. heat hi

Contact between mental and postmental forms a straight or posteriorly
convex line; rarely with point contact between first parietals 56

56. Uniform dark brown color throughout most of body; end of tail white

tipped A. slateri

Body generally not uniformly colored (often with ventral lightening);
caudal tip not especially pigmented 57

57. Postmental shield markedly larger, both in length and area, than men-

tal 58

Postmental shield of same size or smaller than mental 61

58. Two and one-half infralabials ; segments of the tail conical and tuber-

culated; (tip of snout high; lateral-most postmalar very widened; 18-20

caudal annuli) A. spurrelli

Three complete infralabials; segments of tail smooth 59

Fewer than 208 (192-207) body annuli; fewer than 19 (16-18) ventral seg-
ments to a midbody annulus; 18-22 caudals; autotomy at caudal 7-8

A. schmidti

More than 213 (214-236) body annuli; fewer than 20 (14-20) ventral seg-

44 FIELDIANA: ZOOLOGY, VOLUME 72

ments to a midbody annulus; 13-18 caudals; autotomy at caudal 5-8

A. caeca

More than 198 (199-221) body annuli; more than 19 (20-25) ventral seg-
ments to a midbody annulus; 16-21 caudals; autotomy at caudal
5-6 60

60. More than 18 ( 19-21 ) caudal annuli; more than 15 ( 16-18) dorsal segments

to a midbody annulus A. gonavensis hyporissor

Fewer than 20 (16-19) caudal annuli; fewer than 17 (15-16) dorsal seg-
ments to a midbody annulus A. gonavensis leberi

61. Segments of body and tail with squarish tuberculation; four supralabials ;

(medium size; 205-209 body annuli) A. rozei

Segments of body without tuberculation, tuberculation if present only
posterior to caudal autotomy constriction; generally three suprala-
bials 62

62. Two precloacal pores; more than 216 body annuli A. leeseri

Four, very rarely (individual variation) two precloacal pores; fewer than

219 body annuli 63

63. Generally one row of postgenials, or if there are two, the second with very

tiny segments; six to eight postmalars; autotomy constriction at 4th

to 6th caudal annuli; 177-191 body annuli A. hogei

Two rows of postgenials; generally more than seven postmalars; auto-
tomy constriction generally beyond 5th caudal annulus 64

64. Second supralabial generally smallest of supralabials; more than 196

body annuli A. munoai

Second supralabial generally larger than first and third; fewer than 208
body annuli 65

65. Generally fewer than 23 segments in caudal annulus just anterior to

autotomy constriction 66

Generally more than 24 segments in caudal annulus just anterior to auto-
tomy constriction 67

66. Relatively short head; 24-35 segments per midbody annulus; with inter-

calated dorsal half annulus on neck; pigmentation dropping out at

ventral surface, generally in checkered pattern A. p. prunicolor

Relatively elongated head; 27-30 segments per midbody annulus; without
intercalated half annulus in nuchal region; light brown with ventral
fading A. prunicolor albocingulata

67. 178-199 body annuli; 18-23 caudal annuli; 16.5-22 ventral and 13-18 dor-

sal segments per midbody annulus; smooth generally rounded caudal
tip; long tail; medium size; long head shape; color is even to faintly

dotted; ventral surface generally clear A. d. darwini

190-207 body annuli; 13-17 caudal annuli; (15) 17.5-22 ventral and 14-
18.5 dorsal segments per midbody annulus; smooth caudal tip with
faint lateral constriction; short tail; small size; long-medium head

shape; dotted color (often only on anterior body and tail)

A. darwini heterozonata

GANS & MATHER: AMPHISBAENIANS 45

168-208 body annuli; 15-22 caudal annuli; 17-22.5 ventral and 14-21 dorsal
segments per midbody annulus; tuberculate caudal tip; medium tail;
large size; short head shape; markedly and entirely dotted (or lead-
colored); ventral surface generally pigmented A. darwini trachura

REFERENCES

GANS, C.
1962a. Notes on amphisbaenids (Amphisbaenia, Reptilia). 5. A redefinition and a

bibliography of Amphisbaena alba Linne. Amer. Mus. Novit., No. 2105, pp. 1-31.
1962b. Notes on amphisbaenids (Amphisbaenia: Reptilia). Redescription and

range extension of Amphisbaena spurrelli Boulenger. Breviora, No. 171,

pp. 1-11.

1963. Notes on amphisbaenids (Amphisbaenia, Reptilia). 8. A redescription of
Amphisbaena stejnegeri and the description of a new species of Amphisbaena
from British Guiana. Amer. Mus. Novit., No. 2128, pp. 1-18.

1964. Amphisbaena schmidti, a third species of the genus from Puerto Rico
(Amphisbaenia: Reptilia). Breviora, No. 198, pp. 1-11.

1967. A check list of Recent amphisbaenians (Amphisbaenia, Reptilia). Bull.

Amer. Mus. Nat. Hist, 135(2), pp. 61-106.
1974. New records of small amphisbaenians from northern South America. Jour.

Herpetol., 8(3), pp. 273-275.

GANS, C. and A. A. ALEXANDER

1962. Studies on amphisbaenids (Amphisbaenia, Reptilia). 2. On the amphis-
baenids of the Antilles. Bull. Mus. Comp. Zool., 128, pp. 65-158.

GANS, C. and C. O. DA C. DIEFENBACH

1970. Reptilia; Amphisbaenia: Amphisbaenidae. In Peters, J. A. and R. Donoso-
Barros, eds., Catalogue of neotropical Squama ta. Part II, Lizards and amphis-
baenians. Bull. U.S. Nat. Mus., 297, pp. 26-38.

1972. Description and geographical variation of the South American Amphis-
baena angustifrons: the southernmost amphisbaenian in the world (Reptilia,
Amphisbaenia). Amer. Mus. Novit., No. 2494, pp. 1-20.

HOOGMOED, M. S.

1973. Notes on the herpetofauna of Surinam IV. The lizards and amphisbaenians
of Surinam. W. Junk, den Haag, vi+419 pp.

LANCINI, V. A. R.

1963. Una nueva especie del genero Amphisbaena Linne: Amphisbaenidae de
Venezuela. Pub. Ocas. Mus. Cien. Nat., Zool., Caracas, No. 6, pp. 1-4.

SPONGA, M. A. G. and C. GANS

1971. Amphisbaena gracilis Strauch rediscovered (Amphisbaenia: Reptilia).
Copeia, No. 4, pp. 589-595.

STIMSON, A. F.

1972. A new species of Anops from Mato Grosso, Brazil (Reptilia; Amphisbaenia).
Bull. Brit. Mus. Nat. Hist. (Zool.), 24(3), pp. 205-212.

46 FIELDIANA: ZOOLOGY, VOLUME 72

THOMAS, R.

1965. Two new subspecies of Amphisbaena (Amphisbaenia, Reptilia) from the
Barahona Peninsula of Hispaniola. Breviora, No. 215, pp. 1-14.

1966. Additional notes on the amphisbaenids of greater Puerto Rico. Breviora,
No. 249, pp. 1-23.

VANZOLINI, P. E.

1951. Amphisbaena fuliginosa. Contribution to the knowledge of the Brazilian
lizards of the family Amphisbaenidae Gray, 1825. 6. On the geographical dis-
tribution and differentiation of Amphisbaena fuliginosa Linne. Bull. Mus.
Comp. Zool., 7(3), pp. 1-67.

1971. New Amphisbaenidae from Brasil (Sauria). Pap. Avul. Zool., Sao Paulo,
24(14), pp. 191-195.

UNIVERSITY OF ILLINOIS-URBANA