MCZ 
B R E,XJ O R A 
useiim ofj_^(gf^jyi|v||t|[jative Zoology 
I I K I 1 V / r- r-) :-? I -T' \/ 
US ISSN 0006-9698 
Cambridge, Mass. 25 March 1991 Number 492 
A PERUVIAN PHENACOSAUR 
(SQUAMATA: IGUANIA) 
Ernest E. Williams' and Russell A. Mittermeier^ 
Abstract. A small lizard from Venceremos, Department of San Martin. Peru, 
is identified as a hatchling Phenacosaurus and possibly the third known specimen 
of Phenacosaurus orcesi Lazell, 1969. It is the first known specimen of the genus 
from Peru. 
INTRODUCTION 
The anoline lizard genus Phenacosaurus was initially known 
only from Colombia. Its type species, P. heterodermus, was de- 
scribed by A. Dumeril, 1851, in Dumeril and Dumeril (1851), 
from numerous specimens from "Nouvelle Grenade," the name 
of Colombia at that time (including Panama). Dunn (1944) added 
two more Colombian species, P. nicefori ("vicinity of Pamplona, 
Norte de Santander") and P. richteri ("Tabio, Cundinamarca"), 
and Hellmich (1949) still another, P. paramoensis ("Paramo de 
Sumapaz" at the border between Cundinamarca and Meta). The 
latter two have since been synonymized with P. heterodermus 
(Lazell, 1969). A new giant Colombian species has very recently 
been described {P. inderenae Rueda and Hemandez-Camacho, 
1988, from Gutierrez, Department of Cundinamarca). 
Specimens or species known or suspected to be from adjacent 
' Museum of Comparative Zoology, Harvard University, Cambridge, Massachu- 
setts 02138. 
- President Conservation International, 1015 18th Street NW, Washington, D. C. 
20036. 
2 BREVIORA No. 492 
countries have, however, been reported. A specimen from the 
Sierra de Perija (Museo de Historia Natural La Salle, Caracas 
4477), regarded by both Aleman (1953) and Lazell (1969) as P. 
nicefori, is from a peak (Cerro Tetari) in Zulia, Venezuela. (It is 
probably an undescribed species.) The Field Museum's P. nicefori 
(FMNH 5684) from "Paramo de Tana," cited by Lazell (1969), 
may, as Rueda and Hemandez-Camacho (1988) have comment- 
ed, be from Venezuela and not Colombia, since the locality given 
is precisely at the border between the two countries. The latter 
problem is rendered moot by more recent collections, since P. 
nicefori is now known from unpublished material from Betania, 
State of Tachira, further inside Venezuela (specimens in the col- 
lections of the Museo de Ciencias Naturales, Caracas, and the 
Museum of Natural History, Kansas), and a small series of an 
undescribed phenacosaur has been collected by the expeditions 
to the Cerro de La Neblina, State of Amazonas, in the extreme 
south of Venezuela. (These are under study by Charles Myers.) 
Still another phenacosaur, a single specimen in the collection of 
the Museo de Ciencias Naturales La Salle, Caracas, has been 
collected by S. Gorzula and A. Farrera on the Massif de Chimanta, 
a tepuy in the State of Bolivar, in southeastern Venezuela (to be 
described by Williams, Prasiderio, and Gorzula). 
From Ecuador, Lazell, in his 1969 revision, has described the 
very distinctive species P. orcesi on the basis of two specimens, 
the type from "Mt. Sumaco," Napo Province, and a paratype 
from "between L'Alegria [sic] and La Bonita," both localities in 
the Sucumbios Province (formerly the northwest part of the Napo 
Province). Only recently, specimens of another giant species of 
phenacosaur have been collected at La Alegria and adjacent lo- 
calities (specimens in the Museo Ecuatoriano de Ciencias Natu- 
rales, the Escuela Politecnica Nacional, the National Museum of 
Natural History, and in the Museum of Comparative Zoology, 
to be reported on by FEW and collaborators). 
Now a juvenile phenacosaur (MCZ 16521 1) has been collected 
in Peru at Venceremos, in the northern part of the Department 
of San Martin, very near the Department of Amazonas border. 
This juvenile, both because it is small and immature and because 
it is not ideally preserved, is conservatively regarded as the third 
known specimen of Phenacosaurus orcesi despite the great dis- 
1991 A PERUVIAN PHENACOSAUR 
Figure 1. Phenacosaurusorcesijuv., MCZ 16521 1. Lateral view of head. (Right 
side reversed.) 
tance between it and the nearest other specimen of that species, 
the type from Mt. Sumaco. The new specimen is important enough 
to deserve detailed description, provided below in a format elab- 
orated from the one that has been used by the senior author in 
descriptions oi Anolis over many years (see also Figs. 1^). 
DESCRIPTION 
Head 
No trace of a casque, not even the ridges that bound the parietal 
region in adults of the smaller species. All scales smooth. 
Dorsal Head Scales. Antorbital region: Rostral much wider than 
long. Four postrostrals, these defined as all those scales posteriorly 
in contact with the rostral and therefore including the left cir- 
cumnasal that has a narrow contact on that side. The right cir- 
cumnasal is excluded from the rostral by a postrostral. Circum- 
nasals round or ovoid, the nostril nearly central. No differentiated 
anterior or inferior nasals. Each circumnasal broadly in contact 
with the first supralabial of its side. Three scales between the 
circumnasals dorsally. Scales posterior to the circumnasals much 
smaller than the anteriormost canthals, the scales of the frontal 
area, or the median series of three scales anterior to the frontal 
area. 
BREVIORA 
No. 492 
Figure 2. P. orcesi'}u\., MCZ 16521 1. Dorsal view of head. 
Figure 3. P. orcesi ']\iw., MCZ 16521 1. Ventral view of head. 
Frontal depression very shallow. Scales of the frontal area mod- 
erately large, polygonal, markedly varying in size. No rosette of 
larger scales surrounding smaller central scales. Four to six scales 
between the anterior canthals depending upon where the count is 
made. 
1991 A PERUVIAN PHENACOSAUR 
Figure 4. P. orcesi}u\., MCZ 165211. Lateral view of body scales. Arrow 
points anteriorly. 
Canthals five on each side, gently arched, not keeled, the first 
(= the posteriormost) largest on both sides, those on the right side 
grading smaller anteriorly, on the left side the third and fifth larger. 
Orbital region: Scales of the supraorbital semicircles large, two 
scales on the left side in broad contact with three on the right. 
The two largest supraocular scales in contact with the semicircles 
on each side. The next largest supraocular on the right side sep- 
arated from the semicircle of its side by granules; the comparable 
scale on the left in contact with a lateral supraocular scale. The 
other scales of the supraocular areas variable in size, smaller 
laterally. Two to four rows separate the largest supraocular scales 
from the superciliaries. On each side the two anteriormost su- 
perciliaries larger and elongate, the remainder subgranular. 
Parietal region: A parietal eye indicated by a light spot. The 
interparietal apparently fused with other scales: as indicated by 
an anterior median partial sulcus, by the marked asymmetry of 
6 BREVIOR.4 No. 492 
this, the largest scale in the parietal region, and by the slight 
depression containing the parietal eye, which does not at all cor- 
respond to the scale boundaries. The scales lateral to the inter- 
parietal strikingly larger than those posterior to it, although these 
again are sharply distinct from the nape scales. About five rows 
in the approximate midline between the interparietal and the nape 
scales. A penultimate row of the posterior parietal scales markedly 
enlarged. 
Lateral Head Scales. Loreal rows three on the right side, two 
on the left. Total loreals on the right side 1 1, on the left 10. Two 
preoculars (defined as the scales below the anterior comer of the 
eye) on each side, the uppermost in contact with the sulcus be- 
tween the first and second canthals. Four suboculars on the right 
side, three on the left. Postoculars ill-defined, grading into the 
lower temporals. 
Temporals in two areas, upper and lower, separated by the 
double row of slightly enlarged scales on the low ridge that in- 
dicates the lower border of the skeletal supratemporal fenestra. 
Lower temporals smallest centrally; the upper temporals more 
nearly subequal but slightly larger anteriorly. 
Ear many times the size of any adjacent scale, but much smaller 
than the (probably compound) interparietal. 
Supralabials more or less elongate rectangles, seven to nine 
below the center of the eye. 
Ventral Head Scales. Mental very deep, as deep as wide, almost 
wholly divided by a median sulcus, slightly indented by two very 
small medial gulars between the very large first sublabials. Three 
sublabials on each side in contact with the infralabials. Six to 
eight infralabials to below the center of the eye. 
The anterior gulars (those posterior to the medial gulars that 
are in contact with the mental) small, elongate, slightly swollen, 
larger than the central gulars posterior to them, but not as wide. 
The latter becoming more granular and more imbricate near the 
median insertion of the dewlap but larger and still juxtaposed 
next to the sublabial series of each side. Lateral gulars intervening 
between the sublabials and the infralabials at the level of the third 
sublabials, after which it becomes impossible to distinguish be- 
tween lateral gulars, sublabials, and the lateralmost central gulars. 
All gulars subgranular posteriorly alongside the dewlap. 
1991 A PERUVIAN PHENACOSAUR 
Trunk 
No trace of a middorsal crest. Dorsal and flank scales subequal, 
smooth or subimbricate, or (flank scales) sometimes with tiny 
granules visible between them. Ventrals larger, smooth, slightly 
convex, very weakly imbricate, in transverse rows. 
Limbs 
Scales smooth, anteriorly larger and imbricate on lower arm 
and lower leg, separated by naked skin on upper arm and thigh, 
posteriorly granular on upper arm and thigh but not so on lower 
arm and leg. Supradigitals smooth or very weakly carinate, wid- 
ened transversely, lamella-like. Lamellae under phalanges ii and 
iii of fourth toe ca. 21. 
Tail 
Curving at tip as though prehensile, weakly compressed, all 
scales weakly keeled, without a dorsal crest, but the middorsal 
row imbricate and weakly dentate. Enlarged postanals (male) small 
but distinctly larger than surrounding scales. 
Dewlap 
Strongly indicated (juvenile male), distinguished by the longi- 
tudinal orientation of its scales and extending onto belly beyond 
the insertion of the arms. Edge scales smaller than ventrals, lateral 
scales larger than edge scales but, perhaps, smaller than ventrals. 
Size 
Snout-vent length 32 mm; tail length 43 mm. 
Color in life 
(from kodachromes by Russell Mittermeier) 
Ground color cream mottled with brown. Dark brown streaks 
radiating from eye onto supralabials and toward ear. Dorsum 
with three broad dark brown bands variegated with lighter brown. 
Interstices of bands more or less vermiculate with darker brown. 
Limbs banded brown and cream. Small dewlap pinkish or or- 
angish with sparse black spotting. 
8 BREVIORA No. 492 
Locality 
Collected 14 December 1983 by Russell Mittermeier near Ven- 
ceremos ("few houses along the road"): "km 390-39 1 on the road 
between Rioja (6°05'S, 77°09'W) and Pedro Ruiz Gallo (= In- 
genio, ca. 5°56'S, 77°59'W), approximately 91-92 km from Rioja; 
downhill into the forest about one km from the road, on the forest 
floor, within ca. 100 m of a small rainforest stream; elevation 
4,750 ft in steep montane terrain, forest floor well covered with 
moss and humus." The locality is cloud forest with moss-covered 
trees and a springy, mossy floor. Much of the World Wildlife 
Fund film Monkey of the Clouds was shot in the area. The juvenile 
phenacosaur was the only herpetological specimen taken at Ven- 
ceremos in 1983. In 1978, frogs were collected: a number of frogs 
not yet identified, a species of Eleutherodactylus, two undescribed 
species of Colostethus, and toads of the Bufo granulosus and B. 
typhonius complexes. 
Discussion 
Because this specimen is a juvenile it lacks the casque that is 
one of the defining characters of adult phenacosaurs, but a casque 
\sabsQn\
2i\\]\x\Qm\QPhenacosaurus{MCZ 14165:/*. heteroder- 
mus, 30 mm SVL; EPN 2218: P. sp. 38 mm SVL). It also lacks 
the diflerentiated large round flat flank scales separated by gran- 
ules, characteristic of P. hetewdermus, the type species of the 
genus, and present also in P. nicefori and P. inderenae (but these 
are quite absent in the third described species, P. orcesi). In this 
juvenile there is no trace of the median crest present in most 
phenacosaurs (but absence as an individual variation has been 
demonstrated [in adults] for P. hetewdermus [Lazell, 1969] and 
occurs also in the adult paratype of P. orcesi). The Peruvian 
juvenile has two loreal rows on each side and only nine loreal 
scales on one side, 10 on the other, the unmodified circumnasal 
scale broadly in contact with the first supralabial, and a short tail, 
very little longer than snout-vent length, with a curvature sug- 
gestive of prehensility. All are characters congruent with deter- 
mination as a member of the genus Phenacosaurus. It is clearly 
closest to the two known adult specimens of P. orcesi, which it 
matches in the absence of enlarged flat round flank scales. Figures 
5-7 display the head of the paratype of that species, which has 
1991 
A PERUVIAN PHENACOSAUR 
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BREVIORA 
No. 492 
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1991 
A PERUVIAN PHENACOSAUR 
11 
Figure 7. P. orcesi Paratype, USNM 166533. Ventral view of head. 
12 BREVIORA No. 492 
Table 1 . Comparative scale variations in the Peruvian phenacosaur and orcesi 
and heterodermus. 
not been previously illustrated. (The head and body characters 
of the type off. orcesi are figured in Lazell, 1969.) 
It should be parenthetically mentioned that the issue of the 
validity or non-validity of the genus Phenacosaurus does not arise 
in the present context. That this Peruvian specimen belongs in 
the lineage that includes the species heterodermus is not, for us, 
in question. The validity of the genus Phenacosaurus depends 
upon osteological characters not observable in the present spec- 
imen and upon hypotheses of the phylogenetic significance of 
those characters. The placement of the Peruvian animal within 
the postulated lineage orcesi, nicefori, heterodermus depends upon 
external phenetic resemblances, unknown or very unusual in Ano- 
lis, that, in our judgment, demonstrate that these species are a 
clade. 
There are seven differences between the juvenile and the two 
adult P. orcesi, none of these such that they could not be ascribed 
to the sort of individual variation that is rampant in the one well- 
collected species, P. heterodermus. These are in bold face in Table 
1, which records counts for the Venceremos juvenile, the two 
Ecuadorian orcesi, and for 57 heterodermus. It is clear that vari- 
ation in these counts exceeds species boundaries. However, cer- 
1991 
A PERUVIAN PHENACOSAUR 
13 
COLOMBIA 
I 1 r 
100 200 
Figure 8. Map showing the Ecuadorian type locality of P. orcesi (Mt. Sumaco) 
and the locality for the Peruvian juvenile (Venceremos). 
tain counts generally tend to be associated with body size in 
anoles; thus the count of 2 1 for the fourth toe lamellae for the 
Peruvian juvenile may, possibly, indicate that the adults of this 
population might be nearer heterodermus size (maximum SVL 
ca. 80 mm) than orcesi size (known maximum SVL 67 mm). 
There are, therefore, only two reasons for hesitation for rec- 
ognizing the Peruvian juvenile as P. orcesi: (I) the fact that it is 
a juvenile, and (2) the very considerable range extension (more 
than 500 km; Fig. 8) from the southernmost (type) locality Mt. 
14 
BREVIOR.4 
No. 492 
as c. 
" 2 
00 — 
Pu <- 
1991 
A PERUVIAN PHENACOSAUR 
15 
Figure 10. Photograph of the Peruvian phenacosaur in life. Photo by R. A. 
Mittermeier. 
Sumaco, Napo Province, Ecuador (0°34'S, 77°09'W), to Vencere- 
mos, Department of San Martin, Peru (ca. 5°45'S, 77°45'W) (see 
Fig. 9). While P. orcesi is quite distinct from P. heterodermus and 
its relatives, P. nicefori, P. inderenae, and the undescribed giant 
species from Ecuador, the latter are a complex in which the species 
are not very sharply delimited morphologically; it is a possibility 
that P. orcesi is a complex also, and that the Peruvian juvenile is 
a distinct species. Provisionally we assign the Peruvian specimen 
(Fig. 1 0) to the species P. orcesi, but new material and much more 
careful collecting in the montane areas of Peru and Ecuador are 
clearly much to be desired. 
ACKNOWLEDGMENTS 
The figures of the phenacosaurs were done by Laszlo Meszoly, 
the maps by Stephen D. Nash and Laszlo Meszoly. 
16 BREVIORA No. 492 
LITERATURE CITED 
Aleman G., C. 1953. Contribucion al estudio de los reptiles y batracios de la 
Sierra de Perija. Memorias de la Sociedad de Ciencias Naturales La Salle 
[Caracas], 13(35): 205-225. 
DuMERiL, C, AND A. DuMERiL. 1851. Catalogue methodique de la collection 
des reptiles du Museum d'Histoire Naturelle de Paris. Paris: Gide et Baudry, 
224 pp. 
Dunn, E. R. 1944. The lizard genus /*/ze«aco5(3M/-M5. Caldasia, 3(1 1): 57-62. 
Hellmich, W. 1949. Auf der Jagd nach der Paramo-Echse. Deutsche Aquarien- 
und Terrarien-Zeitschrift, 2(5): 89-91. 
Lazell, J. D., Jr. 1969. The genus Phenacosaurus (Sauria: Iguanidae). Breviora, 
Museum of Comparative Zoology, 325: 1-24. 
RuEDA A., J. v., AND J. I. Hernandez-Camacho. 1988. Phenacosaurus indere- 
nae (Sauria: Iguanidae), nueva especie gigante, proveniente de la Cordillera 
Oriental de Colombia. Trianea (Acta Cientifica y Tecnologica INDERENA), 
2: 339-350.