w 
BREVIORA 
MiiseTjinti of Coimparative Zoology 
Cambridge. Mass. April 10, 1!)()4 Number 200 
AN ANGUID LIZARD FliOM THE LEEWARD ISLANDS 
By Garth Underwood 
Department of Zoology, University of the West Indies, Trinidad. 
Through the good offices of Mr. L. Kasasian of the University 
of the West Indies, I received from Mr. J. Phillips, Director of 
Agriculture in Montserrat, a lizard which I was amazed to see 
was an anguid of the genus Diploglossus; the family had not 
previously been known, living or fossil, from the Lesser Antilles. 
Scarcely less amazing was the observation that this lizard resem- 
bles the Central American D. monotropis in respect of several 
major differentiating characters, and differs conspicuously from 
the known Greater Antillean species. 
The specimen was collected in Montserrat by Mr. J. Kingsley 
Howes who tells me that he has only once before seen this lizard, 
and that twenty -five years ago. On the grounds that I am therefore 
unlikely soon to see another I describe for the second time 
(Underwood, 1959a) a new species of Diploglossus on the basis 
of a single specimen. Once again my description contains tedious 
detail, some of which may be eliminated when more specimens 
are examined. As explained in the earlier paper, I do not recog- 
nize the genus Celestus as distinct from Diploglossus. Li the 
condition of the claws, prefontals, nasals, and numerous scale 
organs on the back, this species resembles only D. ynonofropis. 
I therefore borrowed two specimens of monotropis and prepared 
the description with these before me ; the specimens are MCZ 
37139 Yavisa, Panama, and MCZ 15353 Limon, Costa Rica. 
The name of the island of Montserrat is Spanish, from the 
Latin moiis serratus. As this is quite the most remarkable reptile 
yet reported from Montserrat, and as no other reptile bears the 
name of this island, I call it Diploglossus montisserrati. 
BREVIORA 
No. 200 
Family ANGUIDAE Cope 
DiPLOGLOSsus MONTissERRATi iiew species 
Type and only known specimen: adult $ MCZ 76924, and from 
this specimen : left ramus of lower jaw; slide 1, prefontals, frontal 
(damaged), frontoj^arietals, interparietal (damaged), parietals 
and occipital scales ; slide 2, series of 10 scales back from occipital ; 
slides 3a, b and c, 12 longitudinal rows of 10 dorsal scales ; slide 4, 
transverse row of scales from middorsal to midflank ; slide 5, 
three rows of 10 scales forward from groin ; slide 6, transverse 
row of tail scales at level of ankle from middorsal to midventral ; 
slide 7, series of 20 scales back from mental ; slide 8, 25 midbelly 
scales. Collected by J. Kingsley Howes at Woodlands Spring, 
elevation about 600 feet, Montserrat, West Indies, 16° 45i// N, 
62° 13' W. 
Diagiiosis: A large strong-limbed DipJoglossus with sheathed 
claws ; three prefrontal scales ; contact between nasal and rostral 
scales ; numerous scale organs on dorsal scales but none on belly 
scales ; very numerous scale organs on dorsal tail scales ; more 
than 80 scales from occipital to base of tail ; back plain brown, no 
crossbands. 
Fi^. 1. Dorsal view, head of Diplofjlossus montis.serrati type. Area of 
posterior frontal aud frontoparietals may be a little inaccurate owing to 
damage. 
1964 AN ANGUIl) FROM MONTSERRAT 3 
Description: As this species rather closely resembles mono- 
tropis, I note in square brackets the features in which monotropis 
differs. Upon receipt of the tir.st draft of my manuscript Mr. 
Benjamin Shreve kindly examined an additional seven specimens 
of monoivopis: in the Museum of Comparative Zoolo<iy for the 
characters which I had thought useful. His data are incorporated 
here. Shreve 's counts on the type of montisscrraii, when they 
differ from mine, are cited in parentheses. 
Head broad ; Avidth : length to anterior margin of earhole = 
0.83:1. Rostral one and a half times as broad as high, in 
contact with 1st labials, nasals, and supranasals. Pair of supra- 
nasals each meeting other supranasal, rostral, nasal, upper 
postnasal and frontonasal. Pair of frontonasals, each meet- 
ing other frontonasal, supranasal, upper postnasal, canthal 
and median prefrontal. Pair of canthals each meeting fronto- 
nasal, 2 prefrontals, 1st and 2nd loreal and upper postnasal [the 
same or meeting both postnasals and only 1st loreal]. Three 
prefrontals (sutures separating them incomplete posteriorly). 
Median prefrontal meets frontonasals, canthals and lateral pre- 
frontals [and sometimes frontal] ; each lateral prefrontal meets 
median prefrontal, canthal, 2nd loreal [1st or 2nd loreal], 1st 
and 2nd supraoculars [1st and 2nd or 1st only] and frontal. 
Fig. 2. Lateral view, head of Diploglossus montisserrati type. 
Frontal tapers to a point anteriorly, wide posteriorly ; meets pre- 
frontals, 2nd and 3rd supraoculars, frontoparietals and inter- 
parietal; broadly in contact with frontoparietals, narrowly in 
4 BREVIORA No. 200 
contact with interparietal [narrowly or broadly in contact with 
interparietal], excluded from contact with parietals. Palpebral 
aperture large. Four supraoculars, 2nd largest; 2nd loreal just 
meets first supraocular [no loreal meets supraoculars], 3rd loreal 
separated from supraoculars by 1st supraciliary [2nd or 3rd 
loreal so separated]. One subocular intruding only slightly be- 
tween 6th and 7th labials. Six supraciliaries [6 or 7 supracili- 
aries], postoculars 4, 6 [4 or 5]. Five temporals between fronto- 
parietal and labials, anterior lower temporal meets 7th and 8th 
labials. Single nasal meets rostral, supranasal, 1st and 2nd labials, 
and 2 postnasals. Three loreals [two or three loreals] : 1st small 
between 2 postnasals, 3rd labial, 2nd loreal and canthal ; 2nd 
loreal large, between 1st loreal, 3rd and 4th labials, 3rd loreal, 
1st supraciliary, 1st supraocular and prefrontal. [1st loreal 
l)etween lower postnasal, 3rd and 4th labials, 2nd loreal, supra- 
ciliary, prefrontal and canthal] ; 3rd loreal between 2nd loreal, 
4tli and 5th labials, preocular and 1st supraciliary [2nd loreal 
has the same contacts]. Small mental two-third.s width of rostral; 
8, 7 [6 or 8] infralabials, prominent postmental in contact witli 
labials, 1st and 2nd followed by 4 pairs of chin shields, 1st pair 
meeting in midline. Transparent area in lower eyelid covered by 
about 4 vertical scales. 
Middorsal scales from posterior part of neck to root of tail with 
prominent median keel. Keels reduced on tail at about level of 
hindfeet [keels on tail a little more pronounced]. From occiput 
to end of tail, dorsal scales have longitudinal striae. Keels and 
striae fade on lower flank. Scales on underside of body quite 
smooth. Scales on forelimb and hindlimb with striae and slight 
keels on dorsal surface only [no keels on scales of limbs]. Soles 
of feet with swollen soft scales. Vertical ridge-like scale in groove 
between 3rd and 4th toes and soft fold of skin on proximal 
posterior face of 3rd toe [this condition of the 3rd and 4th toes 
is not developed]. Dorsal scales of fingers smooth, dorsal scales of 
toes striated [no striation on scales of toes]. 
Forty-one (43) scale rows at midbody [36-40, also confirmed by 
Boulenger (1885) and Taylor (1956)] ; mental to vent 88 scales 
[85, 90] ; occipital to point above vent 91 scales (occiput to base 
of tail 86) [72-79] ; from anal to chest on line joining axillae 55 
scales [53, 55] ; at level of ankles 20 scale rows around tail [23, 
21]. 
Third digit of forelimb slightly longer than 4th ; lamellae 3rd 
digit: 8, 8 [7 or 8] ; lamellae 4th digit 7, 8 [7 or 8]. Length of 
4th digit of hindlimb to length of 3rd as 1.2:1; 4th toe lamellae 
11,11. 
1964 
AN ANGUID FROM MONTSERRAT 
As indicated, slides were made of scales from various ])arls of 
the body; of the monofropis only ]\ICZ 37139 had sufficient scales 
for a parallel set of i)reparations. 
There are numerous scale organs on the prefrontal, frontal, 
frontoparietal, parietal and occipital scales; there are none on the 
interparietal [many]. 
Ten rows of ten dorsal scales (less three missing) had an 
average of 4.94 [4.71] scale organs per scale. The totals of scale 
organs for ten longitudinal rows of ten showed a variance of 
16.7 per cent ; the totals for ten transverse rows of ten showed 
a variance of 10.6 per cent. This suggests that a transverse or 
oblique row gives a more reliable count than a longitudinal row. 
Six of the scales lacked central keels ; for the others the central 
keel divided the scale organs into two groups, mesial and lateral 
[central keel does not separate two groups]. Counting the scale 
rows from the vertebral line, the majority of scale organs lie on 
the lateral side of rows 1 and 2, the mesial side of rows 3 and 4, 
and all on the mesial side of rows 5 and 6. 
Descending the flank the scale organs become reduced in num- 
ber; on the belly there are none [on belly 2.08 organs/scale]. 
Three rows of ten scales forwards from the groin had a mean 
of 3.43 organs/scale [4.8]. On the dorsal tail scales there are 
very many scale organs, 42 - 73/scale [9 - 11/scale], falling to 
none on the underside [3 - 4/scale]. 
Fig. 3. Mesial view, left ramus of lower jaw of Diploglossus montisscrrati 
type. 
Left dentary bears 20 teeth. Teeth cylindrical ; crowns of an- 
terior teeth laterally compressed, crowns of posterior teeth 
rounded; many of the teeth show signs of wear on the lingual 
side of the crown. The outer face of the dentary has six foramina. 
I am indebted to Dr. Robert Hotfstetter for drawing my attention 
to the existence of a foramen on the inner face of the surangular 
before the posterior branch of the coronoid in the Cordylidae and 
some Anguidae. This specimen has two foramina in this position. 
BREVIORA 
No. 200 
The osteoderms show the network of canals in the basal area 
(buried in the dermis), as described and figured by Hoffstetter 
(1962) for D. monotropis. The distal, epidermis-covered area 
shows radiating canals. The scale organs lie in the portion of the 
skin beyond the margin of the osteoderm. It seems unlikely 
therefore that scrutiny of the osteoderm would give an indication 
of their presence. 
Fig-. 4. Tjower, middorsal osteodcini ; upper left, middorsal scale; 
upper riglit, dorsal tail scale: Diploglossus montisserrnti type. 
General coloration medium bi-owii. Top of head uniform brown, 
upper labials white with a few brown speckles mostly on margins, 
lower labials and underside of head immaculate. Starting on 
neck indistinct darker brown lines; aci-oss width of 12 dorsal 
scale rows plain brown; on flanks and onto side of tail speckles 
1964 AN AXGUID FROM MONTSERRAT 7 
generally covering one or two scales consisting of a dark brown 
mark followed by white ; regenerated portion of tail darker and 
more uniform brown. Legs with speckles similar to those on 
flanks. Underside of body immaculate. D. monotropis has dark- 
edged, white crossbands which Boulenger notes may be broken 
into ocelli on the flanks. Dr. Ernest Williams notes a constant 
dark streak on the temples of moyiotropis as an additional dif- 
ference from montisserrati. 
Dimensions (contorted in preservation) : snout to vent c. 180 
mm, tail (half regenerated) c. 165 mm, forelimb 41 mm, hind- 
limb 45 mm, axilla to groin c. 95 mm. 
DISCUSSION 
We may well ask if the resemblance between monotropis and 
montisserrati indicates close relationship. Reference to the table 
(1959a, p. 13) in my previous paper shows that before the discov- 
ery of montisserrati the only species to combine the four charac- 
ters which I hesitatingly regarded as primitive was monotropis. 
The scale organs on the belly, which I did not notice in 1959, may 
represent an additional primitive character. The only differences 
which are greater than moderate differences of degree are the color 
pattern, the lack of scale organs on the interparietal and on the 
belly, and the very numerous scale organs on the dorsal side of the 
tail and, perhaps, the dorsal scale count. It is therefore difficult to 
suppose that the two species are not related and I suggest that it 
is plausible to assume that, widely separated as they are geograph- 
ically, they have diverged but little from a common ancestral 
stock. As I have previously suggested (1959a, p. 11) monotropis 
appears to be related to fasciatus and resplendens in South Amer- 
ica, to millepunctatus on lonely Malpelo Island and perhaps to the 
limbless Ophiodes. I have not examined material of bilohatus and 
lessonae but it seems possible that these species may be related to 
the monotropis stock with the difference that they have a single 
prefrontal scale (Boulenger, 1855; Schmidt and Inger, 1951; 
Taylor, 1956). In connection with this difference it may be noted 
that the sutures separating the median and lateral prefrontals of 
montisserrati are incomplete. The species of northern Central 
America and the Greater Antilles differ more markedly from the 
monotropis group. In the Greater Antilles, Jamaica and Hispan- 
iola have a diversity of forms while Cuba and Puerto Rico have 
onl}' one species each. The Puerto Rican species has not been 
reported in the Virgin Islands. 
8 BREVIORA No. 200 
It is interesting", therefore, to consider how montisserrati may 
have reached the Leeward Islands. There would seem to be two 
alternatives: either that monotropis-like Diploglossus was once 
widely spread in northern South America and from there reached 
Montserrat, or that monotropis-like stock reached the Greater 
Antilles from Central America and .sj^read eastward as far as 
the Leeward Islands. 
I regard arrival in the Leeward Islands via the Greater Antilles 
as unlikely. No forms are known in the Greater Antilles which 
resemble the monotropis group. We would have therefore to 
suppose that the monotropis stock passed through these islands 
but left no survivors, or that it underwent extensive evolutionary 
transformation there and gave rise to some of the now dissimilar 
modern forms yet survived with little change in the Leeward 
Islands. I have perhaps been too ready to assume in other cases, 
without detailed examination, that a genus which occurs in the 
Greater Antilles and the Leeward Islands has spread eastwards 
from Central America (Underwood, 1963). 
I consider the proposition more plausible that the monotropis 
group was once more widely distributed in northern South 
America. It is a long way from the mainland to Montserrat but 
the journey does not seem much more improl)able than the 
journe}' to Malpelo ; as there are many intervening islands the 
journey may not in fact have been made in one stage. As the 
ocean drift is westwards the take-off point would perhaps be 
somewhere in the Guianas. That there have been changes in the 
fauna of the coastal belt of northern South America is very 
likely. Phyllodactyliis has a distribution whicli is interesting in 
the present connection (Dixon, 1962). It occurs in Barbados, 
Grenada and Puerto Rico ; however, the easternmost record in 
northern South America is Patos Island in the Gulf of Paria, 
between Trinidad and Venezuela. The large and conspicuous 
Anolis richardii is common in Tobago, Grenada, and the Grena- 
dines and St. Vincent but none is known in Trinidad or on the 
mainland (Underwood, 1959b). Evidence of the former occur- 
rence or present survival of the monotropis group in the area 
from the Leeward Islands to the Guianas may yet be discovered. 
Diploglossus (lessonae) does in fact occur in eastern Brazil 
(Schmidt and Inger, 1951) south of the Amazon. 
What is the present status of Z>. montisserrati in Montserrat? 
Whatever may have been tlie manner of its arrival, it is now a 
relict, far removed geographically from relatives. I am inclined to 
]i*64 AN ANGUID F1{()IM IMONTSKRIJAT 9 
regard it as a survivor of the pluvial period, Avliicli lias persisted 
in a favourable habit<it in .spite of the recent climatic changes. 
llllUt barhudcnsis, on the other hand, is an example of a species 
wliieh Avas a])parently unable to survive the drying of the climate 
(Autt'enberg, 19.58). 
Although Montserrat is a small island (321/2 sq. mi.), it is quite 
mountainous with peaks high enough (up to 3000 ft.) to pre- 
cipitate rainfall, and has a good cover of moist forest and a con- 
siderable number of small rivers. Woodlands Spring is on the 
west side of the Island and, according to the 1 :50,000 survey map 
(Directorate of Overseas Surveys) it drains into a small stream 
called Runaway Ghaut. 
Mr. Kingsley Howes writes, "This was the second one that I 
have seen, so they are very rare on the island. The first one I 
saw was about 25 years ago. . . . They were both seen near fresh 
water. The first Avas at sea level near the estuary of a stream, 
the second at Woodlands Spring, the elevation being 600'. I did 
not see either of them feeding, but it is po.ssible that the second 
was feeding on young crayfish which were scurrying around the 
wet rocks where it was found." The stomach of the specimen in 
fact appears to be empty. The occurrence of both near fresh 
water would seem to fit in with the idea that it may be a relict 
of the pluvial period. The fact that there are many damp situa- 
tions in the island means that there may be other surviving 
populations. Taylor describes a specimen of monoiropis taken 
"in vegetation growing at the edge of Lake Bonilla . . . Costa 
Rica." 
Most of the reptile stocks of the Leeward and AVindward 
Islands range through several adjacent islands. The montisscrrati 
stock may well have been more widely distributed in the Leeward 
Islands and indeed may survive on others besides Montserrat. 
Survival on the limestone Leeward Islands, from Anguilla to 
Marie Galante, is unlikely ; they are low lying and dry. Some of 
the volcanic Leeward Islands, from Saba to Basse Terre (Guade- 
loupe), on the other hand, have some good wet forest on their 
higher slopes. Montserrat is one of the islands on which mongoose 
have not been introduced and this may have been a factor in its 
survival. Both St. Kitts, Nevis and Guadeloupe have mongoose; 
however, the mongoose may not extend up to the elevation at 
which the wet forest persists. Saba and St. Eustatius have no 
mongoose but they have very limited moist forest, in fact, only 
inside the crater on St. Eustatius. Several collections of bones 
10 BREVIORA No. 200 
have been made in the Leeward Islands and it would not be 
surprising- if the remains of DipJoglossus were found on islands 
on which it no longer occurs. For this reason I have figured the 
lower jaw and an osteoderm. 
I owe the specimen on which this paper is based to the gen- 
erosity of Mr. Kingsley Howes of Woodlands, Montserrat. I am 
indebted to Dr. Ernest Williams for the loan of the specimens 
of monotropis and for discussion of my manuscript, and to Mr. 
Benjamin Shreve for the report upon additional specimens of the 
mainland species. 
LITEEATUEE CITED 
AUFFENBERG, W. 
1958. A small fossil herpetofauna from Barbuda, Leeward Is., with 
the description of a new species of Hyla. Quart. J. Florida Acad. 
Sci., 21: 248-254. 
BoULEiNGER, G. A. 
1885. Catalogue of lizards in the British Museum (Natural History). 
2d ed., vol II, xiii + 497 pp. 
Dixon, J. 
1962. The leaf -toed geckos, genus Phyllodaclylus, of northeastern South 
America. Southwestern Naturalist, 7: 211-226. 
HOFFSTETTER, E. 
1962. Observations sur les osteodermes et la classification des Anguides 
actuels et fossiles (Eeptiles, Sauriens). Bull. Mus. Nat. Hist. 
Natur., Paris, 34: 149-157. 
Schmidt, K. P. and E. F. Inger 
1951. Amphibians and reptiles of the Hopkins-Branner expedition to 
Brazil. Fieldiana, 31: 439-465. 
Taylor, E. H. 
1956. A review of the lizards of Costa Eica. Univ. Kansas Sci. Bull., 
28: 3-322. 
Underwood, G. 
1959a. A new Jamaican galliwasp (Sauria, Anguidae). Breviora, Mus. 
Comp. Zool., No. 102: 1-13. 
1959b. The anoles of the eastern Caribbean (Sauria, Iguanidae). Part 
III. Eevisionary notes. Bull. Mus. Comp. Zool., 121: 191-227. 
1963. Eeptiles of the eastern Caribbean. University of the West 
Indies, Dept. of Extramural Studies, Jamaica, 191 pp.