Rare snakes--five new species from eastern Panama : reviews of northern Atractus and southern Geophis (Colubridae, Dipsadinae)

48 Pages·2003·5.7 MB·English

by  Myers, Charles W

AMERICAN MUSEUM
Novitates
PUBLISHED BY THE AMERICAN MUSEUM OF NATURAL HISTORY
CENTRAL PARK WEST AT 79TH STREET, NEW YORK, NY 10024
Number 3391, 47 pp., 20 figures, 2 maps, 3 tables February 19, 2003
Rare Snakes—Five New Species from Eastern
Panama: Reviews of Northern Atractus and
Southern Geophis (Colubridae: Dipsadinae)
CHARLES W. MYERS!
CONTENTS
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Gorgas Memorial Laboratory and the Panama Snake Census ....................... +
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Geophis: brachycephalus, (COpey .- 6. 4.6.28 Bn 8 as FRAG AA ee > RAR Pa Pe Glee enka 37
CLEGDUISESPCETCS TG UIFCME ae bP Le wet gg cht ee LTR Bette here tee LIN Rots aee p sects ERs se eg ag 38
CEODIIS HO PINONTIAOW AP ETCES) Fo Biv.s a x bee a poe de hed ye panes ae oer dale & 40
Museum: Abbreviations and Acknowledgments «5 8c ee Ie ae Ae ee 43
INGIETON Coste, 5 oo ATA cocticece Me re foci a EE Or nes eee B Aye PFa ea deel a ce ee RD one 44
‘Curator Emeritus, Division of Vertebrate Zoology (Herpetology), American Museum of Natural History.
Copyright © American Museum of Natural History 2003 ISSN 0003-0082
AMERICAN MUSEUM NOVITATES NO. 3391
ABSTRACT
The South American genus Atractus barely enters political North America on the eastern
half of the Isthmus of Panama, where it is extraordinarily rare. Collected over a period of 39
years, the five Panamanian specimens of Atractus known to the author represent five species!
Four new species are described: A. darienensis, A. hostilitractus, A. imperfectus, and A. de-
pressiocellus. The fifth species is A. clarki Dunn and Bailey, for which a second specimen is
reported from the Colombia Choco. The noncapitate hemipenis of A. clarki may be primitive
in being calyculate and deeply bilobed.
The morphologically convergent Geophis is primarily a Middle American genus—Mexico
to western Panama, with two or three outlying species in the western Andes of Colombia (G.
betaniensis, G. nigroalbus, and probably G. hoffmanni). The genus is unrecorded from eastern
Panama, and a few old records for central Panama seem to have been based on erroneous
specimen data. Nonetheless, the genus does occur in east-central Panama, based on two spec-
imens of G. hoffmanni (W. Peters) and on a specimen each of Geophis bellus, new species,
and G. brachycephalus (Cope)—the latter representing a disjunct population separated by
about 340 km from those in the Boquete area of western Panama.
Geophis bellus is a tiny snake differing from sympatric G. brachycephalus and South Amer-
ican G. nigroalbus in characters of size, color, and hemipenis. Geophis brachycephalus may
be a composite species in western Panama. Unicolored specimens from the Atlantic versant
seem to differ from those in the polymorphic Boquete population in hemipenial and other
characters, and they are set aside as a species inquirenda. The first specimen of Geophis
hoffmanni is reported from Colombia, but it lacks precise data.
Atractus depressiocellus, A. imperfectus, Geophis bellus, G. brachycephalus, and G. hoff-
manni are at least broadly sympatric on the “‘Piedras-Pacora Ridge’’—the continental divide—
between the upper drainages of the Rio Chagres and Rio Pacora, some 30 km northeast of
Panama City. This relatively low upland likely is a premontane forest refuge, where some
very rare snakes may be making a last stand prior to extinction.
RESUMEN
El género Atractus esta ampliamente distribuido en Sudamérica y tiene su limite norte en
la regi6n oriental del Istmo de Panama, adonde es extraordinariamente raro. jLos 5 tnicos
ejemplares panamefios conocidos y estudiados por el autor, colectados a lo largo de 39 afios,
corresponden a 5 especies! Cuatro son especies nuevas que se describen en este trabajo: A.
darienensis, A. hostilitractus, A. imperfectus, y A. depressiocellus. La quinta especie es A.
clarki Dunn & Bailey, de la cual se reporta un segundo ejemplar del Choc6 colombiano. Los
hemipenes no capitados de A. clarki podrian ser primitivos por ser caliculados y profunda-
mente bilobulados.
Geophis, que es morfol6gicamente convergente con Atractus, es primariamente un género
mesoamericano—se distribuye desde México hasta el oeste de Panama, con dos o tres especies
aisladas en los Andes occidentales de Colombia (G. betaniensis, G. nigroalbus, y probable-
mente G. hoffmanni). Geophis no ha sido registrado hasta ahora en el este de Panama, y unos
pocos registros viejos del centro de Panama parecen haber sido basados en especimenes de
procedencia incierta. Sin embargo, el género ocurre en el centro-este de Panama, como lo
indican dos especimenes de Geophis hoffmanni (W. Peters), un espécimen de G. bellus (especie
nueva), y un espécimen de G. brachycephalus. Este tltimo representa una poblaci6n disyunta,
distante aproximadamente 340 km de las poblaciones mas cercanas en el oeste de Panama.
Geophis bellus es una pequefiita culebra que se diferencia de la especie simpatrida brachy-
cephalus y de la sudamericana nigroalbus en caracteres de tamafio, coloracién y hemipenes.
La especie polimoérfica G. brachycephalus podria ser una especie compuesta en el oeste de
Panama. Ejemplares monocromiaticos de la pendiente atlantica parecen diferir en caracteristicas
de los hemipenes y de otros caracteres, y son mantenidos como especie inquirenda. Se reporta
el primer espécimen de Geophis hoffmanni de Colombia, aunque faltan datos precisos.
Atractus depressiocellus, A. imperfectus, Geophis bellus, G. brachycephalus, y G. hoffmanni
son ampliamente simpatridas en la “‘cresta Piedras-Pacora’’, la divisoria de los altos drenajes
de los rios Chagres y Pacora, unos 30 km al nordeste de la ciudad de Panama. Esta serrania
2003 MYERS: SNAKES FROM PANAMA 5
baja es probablemente un refugio de bosque montano, adonde algunas serpientes muy raras
podrian presentar una Ultima resistencia a la extincion.
INTRODUCTION albiceps is Barro Colorado Island, which
supports one of the world’s best known trop-
This paper is about some rare snakes on
ical herpetofaunas (Myers and Rand, 1969;
the eastern half of the Isthmus of Panama.
Biologists familiar with the great diversity of Rand and Myers, 1990). Perhaps Tantilla al-
biceps is extinct, at least on Barro Colorado
serpents in tropical rain forests know that rar-
ity or the appearance of rarity is compounded Island. Perhaps biologists on the island have
by several factors, including: (1) many, in- failed to differentiate an occasional specimen
from the more common and similar appear-
deed most, wet-forest snakes seem to have
low population densities relative to temperate ing Enuliophis sclateri. Such explanations
are unverifiable and unsatisfactory.
species; (2) many are hard to find because of
Five or six species in the two genera of
secretive habits; and (3) some are less likely
to be encountered because of small geo- concern in this paper seem to be, like the
example above, really rare, although to be
graphic ranges and/or specialized microhab-
sure they come from less well-trodden
itats.
ground. The terrestrial or semifossorial
With time, however, sufficient specimens
accumulate to allow approximation of geo- snakes of the genus Atractus reach the north-
graphic and ecologic distributions and as- ern limits of the generic range in east-central
Panama. To my knowledge, only five Pana-
sessment of morphological variation. But
there are exceptions to this generalization— manian specimens of Atractus have been col-
there are snakes seemingly rare in an abso- lected—in the years 1936, 1938, 1966, 1967,
1974—-with each specimen a different spe-
lute sense, so rare as to resist verifiable ex-
planation of their rareness. For example, the cies, of which one was named in 1939 and
the other four are described herein.
little Tantilla albiceps is known to science
only from a single specimen that was found The second genus of concern, the semi-
fossorial Geophis, ranges throughout much
in central Panama three-quarters of a century
of Middle America and occurs also in the
ago (Barbour, 1925); the type locality of 7.
western Andes of northern South America.
? Pérez-Santos and Martinez (1997: 451) erroneously Geophis is well known from Costa Rica and
reported Tantilla albiceps from Isla Coiba off the Pacific western Panama, but published records for
coast of western Panama; this record is based on a spec-
central Panama are based on erroneous lo-
imen of the widespread Enulius flavitorques. The col-
cality data and the genus has not been doc-
lector, Ignacio De la Riva, kindly provided photographs
of the specimen in life, showing a smooth-scaled, long- umented from the eastern half of the isthmus.
tailed small snake, dark brown above, grayish white on I am still unaware of specimens from ex-
the lower few scale rows. The dark dorsal coloring is
treme eastern Panama, but four snakes rep-
conspicuously broken by a yellowish nuchal collar
resenting three species of Geophis were col-
crossing the rear halves of the parietals; the collar is
interrupted by a small irregular brown blotch posteriorly lected in east-central Panama in the 1950s
on the interparietal suture. The left side of the head in and 1960s. Two specimens represent a sim-
profile shows a prominent rostral, a longer-than-high lo- ple range extension of the widely distributed
real plate entering the eye (no preocular), two postocu-
G. hoffmanni, whereas a third specimen pro-
lars, and 1 + 2 temporals. All these characters match
well with E. flavitorques. vides a widely disjunctive eastward exten-
According to J.M. Savage (personal commun.), the sion of G. brachycephalus. The fourth spec-
unpublished notes of E.R. Dunn contain reference to a imen is of an undescribed species that is
second specimen of Tantilla albiceps from Barro Colo-
named herein.
rado obtained in 1952, but no one else seems to have
Apparent rarity often implies insufficient
been aware of the specimen, and its whereabouts is un-
known (there is no second specimen of T. albiceps en- collecting, and certainly the survey of the
tered in the electronic databases of ANSP, FMNH, or rich Panamanian herpetofauna is not (and
MCZ—the main depositories for Panamanian specimens may never be) complete. Nonetheless, Pan-
examined by Dunn in the early 1950s). No other spec-
amanian snakes have been better collected
imens have been reported (Ibafiez et al., “‘1995”’ [1997]:
153,2156); than in most tropical countries. My claims of
- AMERICAN MUSEUM NOVITATES NO. 3391
unusual rarity for some of the snakes in hand Dunn and Bailey, 1939). Dunn obtained
can be put in perspective by consideration of background information on the census meth-
the activities of the Gorgas Memorial Labo- ods during his visits to GML starting in
ratory (GML), which operated out of Panama 1939, and his 1949a paper is the most com-
City from its opening in 1929 until its un- plete and easily accessible summary of
fortunate demise in 1991. (GMLs parent cor- Clark’s GML snake census.
poration in Washington, D.C.—the Gorgas Dunn’s 1949a account, however, did not
Memorial Institute of Tropical and Preven- include the census collections from most of
tive Medicine, Inc.—subsequently was reor- western Panama nor from the limited uplands
ganized in name under the Ministry of of eastern Panama (see below). But new spe-
Health in Panama, but GML had been de- cies, new country records, and other note-
pendent on a permanent annual contribution worthy specimens from those areas were re-
from the U.S. Congress for its core support.) ported elsewhere (Dunn, 1942; Dunn and
Bailey, 1939). Unfortunately, over 90% of
GORGAS MEMORIAL LABORATORY (GML) the GML specimens were apparently discard-
ed after Dunn’s study, except for whole spec-
AND THE PANAMANIAN SNAKE CENSUS
imens and selected heads especially of rare
Dr. Herbert C. Clark (1877-1960), first Di- species that were placed in major museums.
rector of the Gorgas Memorial Laboratory, Fewer than 1000 specimens with data were
initiated a snake census in Panama and con- saved from the Panama snake census, which
ducted it at varying levels of intensity from spanned a quarter of a century.*
January 1929 through 1953 (he retired in A total of 13,745 snakes, mostly heads
1954). Not a new concept, the census was only, were accumulated in the overall period
started as an extension of a then ongoing 1929-1953 (Wright, 1970: 269). Dunn
Central American snake census that used the
labor forces on plantations of the United 3 In describing one of the heads as a new species (Dip-
Fruit Company. Clark had earlier supervised sas nicholsi [see Cadle and Myers, 2003]), Dunn (1933)
the snake census in Tela, Honduras, but, with acknowledged ‘“‘the authorities of the Museum of Com-
parative Zoology for permission to examine the collec-
the resources of GML, Clark expanded the
tion’? (Dunn, 1933: 193). Later, however, it seems cu-
census in Panama well beyond the planta-
riously inappropriate for Dunn (1949a: 39, 55) to have
tions and continued it for a quarter of a cen- stated that the specimens were sent directly to him “‘dur-
tury. ing the years 1933 to 1945 inclusive, by Dr. H. C.
Clark’s primary aim was to learn the ven- Clark’’—without mention of the MCZ or, especially,
without acknowledgment to the late Thomas Barbour
omous species in Panama and to assess their
(died in 1946), who funded Dunn’s early fieldwork in
relative medical importance (Clark, 1942). the Neotropics (Adler, 1989: 93). According to the GML
Bounties were paid for killed snakes (mostly annual reports, yearly shipments of snakes were sent to
heads), which were accumulated in formalin the MCZ at least through 1938 and 1939, and the MCZ
continued to be mentioned as a cooperating institution
in central locations around the country. The
through 1943; Dunn’s identification services were ac-
GML snake census was initiated in cooper-
knowledged starting in the report for 1939, and the MCZ
ation with the old Antivenin Institute of is not mentioned after 1943.
America, one of whose founders was Thom- 4 The following counts are derived from collection da-
as Barbour. In 1932, Barbour involved the tabases: Clark sent the early material to the MCZ, in-
cluding 411 specimens from the Panama census and
Museum of Comparative Zoology (MCZ) of
some 300 from his prior Honduran census. E.R. Dunn
Harvard University, which “‘became actively subsequently presented 273 of Clark’s Panamanian spec-
interested in the studies and supported them imens to the ANSP, starting with a few specimens in
in part’ (Wright, 1970: 269). Early ship- 1939 and with the bulk being given during the early
1940s. Finally, with Clark’s approval, Dunn and GML
ments were sent to the MCZ (e.g., Clark,
staff member H. Trapido (see footnote 20) saw to it that
1937: 12), from where Barbour turned over
256 specimens from the Panama census went to the
the identification and study of the collection FMNH after Dunn’s examination (Clark, 1952: 20). A
to his former student E.R. Dunn, who iden- jar of uncataloged heads without data is also at FMNH
tified most of the material. Dunn eventually (Alan Resetar, personal commun.). In Panama, a small
number of specimens were kept for identification pur-
took over the study and reported on the re-
poses at least at GML and at Barro Colorado Island
sults (Dunn, 1933, 1942, 1949a, 1949b; (Myers and Rand, 1969: 5).
2003 MYERS: SNAKES FROM PANAMA Gy)
(1949a: 39, 55) reported on nearly 80% of herein; the other Geophis specimens repre-
the collection, that is on “‘10,960’’> speci- sent two species named in the 19th century.
mens from the lowlands of central Panama The first two of the aforesaid nine speci-
(““Chagres collection’’) and from the Pacific mens were obtained by the GML census in
lowlands of west-central and eastern Panama 1936 and 1938. I collected another two while
(combined collections from ‘‘Coclé-Herre- resident Visiting Scientist at GML during
ra’, ““Sabanas”’, “‘Darién’’). Excluding 1073 1964-1967. And five experienced field men
museum specimens, savanna collections, and (several earlier trained as collectors at GML)
those collections from west of the Panama each caught one of the other five specimens
Canal, Dunn’s (1949a; table 7) list of 70 spe- in the 23-year period 1952-1974.
cies includes 2500 snakes from forested low- As a further indication of rarity, it may be
lands in the Chagres drainage of central Pan- noted that five of the eight species (A. de-
ama and 3044 snakes from areas of mixed pressiocellus, A. imperfectus, G. bellus, G.
banana plantations and forest in the Darién brachycephalus, G. hoffmanni) are from the
of eastern Panama. region of the Piedras-Pacora Ridge, only
about 30 km northeast of Panama City. The
Neither Atractus nor Geophis is included
Piedras-Pacora Ridge—a section of the con-
in the nearly 11,000 lowland specimens ob-
tinental divide—delimits part of the south-
tained by the GML snake census and report-
eastern side of the Madden Lake® watershed,
ed in Dunn’s (1949a) summary paper. The
and is now included in the Parque Nacional
absence of Atractus and Geophis from the
Chagres. A team of Panamanian herpetolo-
large lowland collections seems surprising at
gists (Ibafiez et al., “1994” [1995]) surveyed
first blush, inasmuch as there are many
the herpetofauna of the Piedras-Pacora Ridge
Atractus occurring in the South American
in 1990-1995; they invested 1253 man-hours
lowlands and a specimen of Geophis hoff-
of collecting in both wet and dry seasons (in-
manni was collected not far from the Panama
cluding 166 man-hours at night in the wet
Canal in 1968. Recent sampling in the cen-
season). Their list is extensive, totaling 131
tral Panamanian lowlands has yielded neither
species of amphibians and reptiles, including
Atractus nor additional specimens of Geo-
37 species of snakes. Among the small
phis (Ibafiez et al., “1995” [1997]).
snakes collected was the third known speci-
Clark also pursued collections of snakes
men of Coniophanes joanae, but no new
from upland areas, which are of limited ex-
specimens of the still elusive Atractus or
tent in central and eastern Panama. Dunn and
Geophis.
Bailey (1939: 3) reported on “268 snakes
The Piedras-Pacora Ridge may be a pre-
from the uplands of eastern Panama gathered
montane forest refuge for some small part of
in 1936 to 1938 through the initiative of Dr.
the fauna that is barely surviving the climat-
H. C. Clark’’. There are no Geophis in this
ic-vegetational vicissitudes of the Pleisto-
collection, which, however, provided the first
cene. The mingling of several very rare spe-
two specimens of Atractus from Central
cies in one place, including three species
America.
known only from that place, leads me to fear
There are eight species to be reported in
that it may be their “‘last stand”’ on the way
the following pages (maps 1, 2). These eight
to extinction. Should this be so, their Latin
species are represented by a total of nine cen-
names may be their only epitaphs.
tral and eastern Panamanian specimens—five
specimens of Atractus and four of Geophis.
METHODS OF STUDY
One Atractus was named in 1939; four spec-
Total length and tail length were deter-
imens of Atractus and one of Geophis rep-
mined by moderately stretching preserved
resent five “‘new’’ species that are named
specimens along a metric rule. Head and
snout lengths, eye length, and head plates
> Apparently a minor error, repeated later (Dunn,
and their sutures were measured to the near-
1949b). Adding the column totals in Dunn’s (1949a) ta-
ble 7 gives a grand total of 10,693 specimens. His count
of 1073 museum specimens on page 55 agrees with the © Madden Lake is shown as Lago Alajuela on recent
column totals in the table. maps.
6 AMERICAN MUSEUM NOVITATES NO. 3391
tractus clarki
. darienensis
. hostilitractus
. Imperfectus
. depressiocellus
Map 1. Eastern Panama, showing locality records for the five Central American species of Atractus.
One species (A. clarki) is also known from a specimen of indefinite locality in the Colombian Choco,
the others are known only from the Panamanian holotypes. Type localities: (1) Santa Cruz de Cana, an
old gold mine; (2) north end of the Serrania de Pirre; (3) “‘Morti Hydro’’, a temporary helipad near the
Rio Morti; (4) Piedras-Pacora Ridge; (5) Cerro Jefe on the Piedras-Pacora Ridge.
est 0.1 mm with an ocular micrometer in a whereas one such as eye length/eye-to-lip
dissecting microscope. Some measurements may or may not match a figure, depending
are used for comparisons, but most were con- on perspective of the drawing (e.g., dorso-
verted to proportions for purposes of descrip- lateral or lateral) and degree to which the lip
tions. It bears emphasizing that snout length is flared.
(tip of snout to eye) was not measured on the The drawings are my own, made with the
oblique angle but on the sagittal plane by oc- aid of a camera lucida fitted to a Wild dis-
ular micrometer, whereas head plates and the secting microscope. I photographed speci-
distance from eye to lip were determined mens positioned under glass on a raised plas-
along the plane of the greatest dimension, tic platform to eliminate shadows, and under
meaning that the head had to be differently alcohol to reduce glare from reflective sur-
inclined for different measurements. There- faces of scales.
fore anyone comparing the descriptions with Ventral plates were counted by the Dowl-
the drawings will have to be alert to the usual ing (1951) method, starting with the first
problems of parallax: In no case, for exam- plate bordered on each side by the first dorsal
ple, will a proportion such as nasal plate/lo- scale rows; gular plates anterior to this, if
real plate be retrievable from the figures, wider than long, were termed preventrals
2003 MYERS: SNAKES FROM PANAMA i
@ Geophis bellus
® G. brachycephalus
® G. hoffmanni
Map 2. Locality records for three species of Geophis known to occur in eastern Panama. The
easternmost localities indicate broad sympatry on the Piedras-Pacora Ridge in Panama Province.
(Myers, 1974: 37) for purposes of comparing method over the older one summarized by
type specimens with old original descriptions Schmidt and Davis (1941: 26):
in which these plates were included in ven-
The ventrals and caudals of snakes correspond (with
tral counts.
some variation) to the number of vertebrae. It is cus-
Dowling’s method has the advantage of tomary to count their number beginning beneath the
giving a standard starting place for ventral chin with the first one distinctly wider than long [em-
counts that was said to correspond (in some phasis added], and excluding the anal plate ... The
first caudal, when they are in two rows, is the first
snakes) in position with the atlas-axis artic-
one that meets one of the opposite side. It is custom-
ulation of the vertebral column. But the first ary to count them on only one side, and to include
ventral is not always quickly ascertained in the terminal single scale [however, most workers
nowadays do not count the terminal spine as a sub-
the case of small, poorly preserved snakes
caudal].
with shiny scales, and I am sorry to have
adopted this method some years ago. I sel- Downs (1967: 23) may have found a reason-
dom notice more than a few “‘preventrals’’, able compromise between the above and
but comparisons with older literature are less Dowling’s sometimes tedious method of de-
accurate if these are not counted and added termining the first ventral:
to the total. Therefore, I would not be critical
The ventrals were counted from the first scale clearly
of anyone refusing to adopt the Dowling twice as broad as long ... this system does not fol-
8 AMERICAN MUSEUM NOVITATES NO. 3391
low the suggestion of Dowling (1951), but in practice in Fairchild and Handley (1966), whose im-
is identical or nearly identical with it. portant gazetteer of GML and other collect-
ing stations was based on an earlier 3-sheet
The practical reason for the above digression
1:500,000 map of the Republic.
is to be seen in this paper in footnote 19. As
a further aside, only a few workers (e.g., Pe-
ters, 1960: 10—12) have mentioned the oc- GENUS ATRACTUS
casional divided or “‘half-ventrals’’, which
Atractus is a large South American genus
may occur anywhere but are most common
whose range is now known to include the
in some snakes just anterior to the anal plate.
eastern half of Panama (map 1), where it
These correspond to anomalous vertebral du-
seems to be exceedingly rare. The four whole
plications (King, 1959) and are not counted,
specimens (figs. 1, 2) and the one head (fig.
although it may be useful to mention their
10) known to me represent five species! Two
occurrence in holotypes.
of these specimens come from the low up-
Except when a dentigerous bone was dis-
lands east of the Canal Zone and three are
sected out for illustrating, maxillary teeth
from Darién; all localities are in well-drained
were counted in situ (Myers, 1974: 27); the
(100 to >500 m) monsoon rain forest (My-
once common practice of excising maxillae
ers, 1969).
from rare snakes for the sole reason of count-
I have been unable to match any of the
ing teeth is neither necessary nor justified.
Panamanian specimens with previously
Hemipenes were treated as described in
named South American species. But identi-
Myers (1974), except that everted organs
fying Atractus is often difficult owing to the
were inflated with carmine-dyed petroleum
many inadequate, poorly illustrated descrip-
jelly (rather than wax or latex). A few hem-
tions that usually emphasize characters pre-
ipenes in preserved specimens were manu- sent in a majority of species. A major review
ally everted from either the retracted state
of the genus is needed. There have been good
(fig. 17) or from partially everted organs
taxonomic and variational studies for Ecua-
(figs. 14, 20B), after they were dissected out
dor (Savage, 1960), Venezuela (Roze, 1961,
and then soaked first in glycerin and finally
1966), Surinam (Hoogmoed, 1980), and east-
in a saturated solution of trisodium phos-
erm and central Amazonia (Cunha and Nas-
phate to restore elasticity. Although hemi-
cimento, 1983; Martins and Oliveira,
penial eversions made from preserved spec-
1993)—but the situation is less good for Co-
imens may be fully everted with all struc-
lombia, which has a rich Atractus fauna of
tures showing, some such organs may be less several dozen named species, whose varia-
completely inflated (i.e., less robust) than tion and relationships are virtually unknown
fresh preparations. Techniques are reviewed
(lists of nominal species in Daniel, 1949; Pe-
by Myers and Cadle (Ms).
ters and Orejas-Miranda, 1970; Sanchez-C.
All specimens were collected long before
et al., 1987; Pérez-Santos and Moreno,
the availability of Global Positioning System 1988). Although a majority of Colombian
(GPS) satellite receivers. The detailed 1: Atractus are Andean, it would not be sur-
50,000 map series of Panama is still incom- prising if an older Colombian (or other South
plete and, with one exception (See Atractus American) name were eventually found to be
hostilitractus), topographic maps of this applicable to one of the purportedly new spe-
scale are still unavailable for the type local- cies herein described as Panamanian endem-
ities in this paper. Therefore, approximate ics. To ease the burden of workers who may
geographic coordinates were determined have to decide this point without ready ac-
mainly from the maps Canal Zone and Vi- cess to all holotypes, the five Panamanian
cinity 1:100,000 (1957 edition, U.S. Army specimens are described and illustrated in
Map Service, Washington, DC) and the 12- some detail. I additionally discuss and illus-
sheet Mapa General de la Republica de Pan- trate a Colombian specimen of Atractus clar-
amd 1:250,000 (Ist ed., circa 1966—1967, ki Dunn and Bailey, a species heretofore re-
Direccion de Cartografia, Panama City). ported only from the Panamanian holotype.
Some coordinates differ slightly from those This genus has been confused with Geo-
2003 MYERS: SNAKES FROM PANAMA 9
phis, but, in Panama, known Atractus are cially close relationship between Atractus
easily distinguished by the generic character- and the Middle American Adelphicos.
istic of a single pair of genials (two pairs in Panamanian Atractus share a number of
southern Geophis) and 17 rows of smooth features’ that are possessed by a majority of
scales (15 rows of scales, smooth or poste- Species in the genus (e.g., see data matrix in
riorly keeled in southern Geophis); also, the Peters and Orejas-Miranda, 1970: 24-26).
southern Geophis have a usually diamond- They have 17 dorsal scale rows, large pre-
shaped or rhomboidal frontal plate that is frontals that are in contact with the eye, usu-
strongly angular anteriorly (as in fig. 12), ally two postoculars (2/3 in one), no preo-
whereas Panamanian Atractus have a more cular, an elongated loreal plate, seven su-
normal colubrid frontal that is roughly tri- pralabials, first pair of infralabials in contact
angular or pentagonal, with only a small an- behind the mental, and a basically cross-
terior apex at the prefrontal suture (fig. 3). banded or blotched color pattern. The five
Unfortunately, the four whole specimens Panamanian specimens/species are identifi-
of Panamanian Atractus are all females and
able by the following key (see also compar-
furnish no data on male genitalia, although
ative figures, diagnoses, and table 1):
opportunity is taken to describe and illustrate
a hemipenis from the Colombian specimen
KEY TO PANAMANIAN ATRACTUS
of A. clarki. Hemipenial differences men-
tioned by Savage (1960: 30) have since bro- 1. Venter black or clouded with dark pigment;
ken down with further study of Geophis (see no pale dashes on lower scale rows; eye
Downs, 1967: 184, and discussion herein un- length less than or scarcely greater than
der Geophis bellus), and the distinction is distance from its lower edge to lip .... 2
further blurred by the hemipenis of Atractus — Venter pale (fig. 2A); lower scale rows with
clarki (q.v.). Cadle (1984) considered Atrac- pale centers; eye length noticeably greater
tus a South American member of a mainly than distance to lip (fig. 3A) .........
Central American xenodontine clade—now
2. Neck black with pale rings, or with black
recognized as the subfamily Dipsadinae—for
bands several times wider than those pos-
which the most diagnostic of several derived
teriorly on body; eye moderate, going less
hemipenial features is the distal division of
than 2.5 times into loreal; total length less
the sulcus spermaticus (Myers and Cadle,
than 500 mm (<400 mm in two females)
1994: 27; Zaher, 1999: 33). The sulcus sper-
maticus in the Dipsadinae usually divides — Neck brown like body, with black transverse
close to or within the capitulum; the hemi- lines not greatly wider than on rest of body
penis of A. clarki is noncapitate and the sul- (fig. 1C); eye very small (fig. 3E), con-
cus divides slightly below the midpoint of tained about three times in loreal plate; size
the organ (at least in the retracted condi- large (one female 750 mm total length) ..
tion)—somewhat lower than in most dipsa- Ror bebi eteak PAL TS ee By oe A. depressiocellus
dines but still higher than the basal bifurca- 3. Snout bluntly pointed in profile (fig. 9A, C);
tion in the great majority of Xenodontinae (in loreal well separated from internasal; labi-
alSsimoOsthy, WHE iokee Ie a aeeeeeee sd +
which the sulcate bifurcation may rarely ap-
— Snout in profile rounded like a coral snake
proach the midpoint of the organ, e.g., see
(fig. 9B); anterior corner of loreal ap-
Zaher, 1999: fig. 64, upper).
proaching or touching corner of internasal;
Atractus and Geophis have been often
labials mostly black; neck black with sev-
compared, but the closeness of their relation-
eral pale rings, changing posteriorly to light
ship is questionable and they are probably reddish brown ground color (red in life?)
convergent to a similar life-style. On the ba-
sis of immunological comparisons, Cadle
7 A peculiarity shared by four of the five Panamanian
(1984) saw a closer relationship for Geophis specimens, and some others I have seen, is that the
with Ninia and other Middle American dip- asymmetrical suture between the prefrontal plates is no-
ticeably dextral to the internasal suture (fig. 3). The dex-
sadines than with Peruvian Atractus elaps
tral orientation also is seen in seven of eight species
and A. major. Zaher (1999: 33) suggested,
figured by Hoogmoed (1980). Some Atractus have the
on the basis of a muscle character, an espe- two sutures aligned in the normal colubrid manner.
10 AMERICAN MUSEUM NOVITATES NO. 3391
Fig? Panamanian Atractus: Holotypes in dorsal view. A. A. clarki Dunn and Bailey (MCZ 28800),
X1.0. B. A. darienensis, new species (KU 110274), X0.8. C. A. depressiocellus, new species (AMNH
119876), X0.4. D. A. hostilitractus, new species (AMNH _ 130330), X0.8. See figure 10 for a fifth
Panamanian species (Atractus imperfectus, new species).
Atractus clarki Dunn and Bailey
elke ER ns somes phe Phe ioS PE A. hostilitractus
Figures 1A, 2A, 3A, 4, 53 map 1
4. Neck with black saddles (fig. 1B [obscure in
life]) several times wider than posterior Atractus clarki Dunn and Bailey, 1939: 8—9 (ho-
black bars, but narrow interspaces between lotype: MCZ 28800, an adult female collected
anterior saddles brown like rest of ground by native worker in 1938, at Mine at Santa Cruz
color, not whitish (or red or yellow); rostral de Cana [approx. 7°46'N, 77°41'W, 500 ml],
narrowly visible in dorsal view; eye length Province of Darién, eastern Panama).
less than 90% of distance to lip ......
SNR ont Wa on ee ee ae oa A. darienensis DIAGNOsIS: Atractus clarki is readily dis-
— Neck black with pale bars or ringlike mark- tinguished from other Panamanian species in
ings (fig. 10 [posterior pattern unknown]);
having a uniformly pale venter, narrow pale
rostral plate well visible in dorsal view; eye
dorsal bars, pale dashes on the lower scale
length about equal or slightly larger than
distance to lip rows, and in having a relatively large eye
whose length is noticeably greater than its