A New Fossorial Snake Of The Genus Geophis (Reptilia, Serpentes, Colubridae) From The Cordillera de-Talamanca Of Costa rica

7 Pages·1994·2.1 MB·English

by  K R Lips

PROC. BIOL. SOC. WASH.
107(2), 1994, pp. 410-416
A NEW FOSSORIAL SNAKE OF THE GENUS GEOPHIS
(REPTILIA: SERPENTES: COLUBRIDAE) FROM THE
CORDILLERA DE TALAMANCA OF COSTA RICA
Karen R. Lips and Jay M. Savage
—
Abstract. Geophis talamancae, a new species ofcolubrid snake from south-
central Costa Rica is described. The new form belongs to the sieboldi group,
which includes five Mexican species, G. nasalis (Guatemala), G. hoffmanni
(Honduras to western Panama), G. zeledoni(central Costa Rica), G. nigroalbus
(eastern Panama to Colombia), and G. brachycephalus (northern Costa Rica,
Panama and Colombia). We reallocate Geophis betaniensis ofColombia, pre-
viously referred to the championi group, to the sieboldi group; present scale
counts of G. godmani from populations geographically intermediate to those
previously known; comment on distinguishing between Geophis and Atractus
on the basis of chin shields and temporal scales; and present a key to the
Geophis species ofLower Central America and Colombia.
Resumen.—En este trabajo se describe a Geophis talamancae, una nueva
especie de serpiente colubrida del centro-sur de Costa Rica. Esta nueva forma
pertenece algruposieboldi, el cual incluye a 5 especies mexicanasya G. nasalis
(Guatemala), G. hoffmanni(HondurasaPanamaoccidental), G. zeledoni(Costa
Rica central), G. nigroalbus (Panama oriental hasta Colombia) y G. brachy-
cephalus (norte de Costa Rica, Panama, y Colombia). Se reasigna a Geophis
betaniensisde Colombia, previamenteenelgrupo championi, algruposieboldi;
se proporcionan niimeros de escamas de G. godmani de poblaciones inter-
medias geograficamente a las conocidas anteriormente y se comenta sobre la
distincion entre Geophis y Atractus con base en las escamas geneiales y tem-
porales. Finalmente se presente una clave para las especies de Geophis del sur
de Centroamerica y Colombia.
A single example ofa rather nondescript Canton Coto Brus: Zona Protectora Las
m
snake of the genus Geophis was collected Tablas, Finca Jaguar, 1800 elevation;
during a survey ofthe herpetofauna ofthe taken 1 Sep 1992 by Karen R. Lips.
Zona Protectora Las Tablas ofthe Reserva Etymology.—The species name is de-
delaBiosferalaAmistadofCostaRica,near rivedfromtheCordilleradeTalamanca,the
the Costa Rica-Panama border by the se- mountain range from which the specimen
nior author in 1992. A comparison with was collected.
otherGf-op/z/^confirmsthattheuniquetype Definition.—The features listed below
appears to represent a population that may characterize the species and follow the for-
be called: mat used by Downs (1967) in his revision
ofthe genus: 1) dorsal scale rows in 15-15-
Geophis talamancae, new species
^3 ^^^^ ^^^^^^^^ ^^^1^^ ^^ posterior half
^^' of body; 2) no anterior temporal; 3) one
Holotype.—CRE 5343, an adult female supraocular and one postocular scale; 4)
from Costa Rica: Puntarenas Province: snoutbluntandshovel-shaped,rostralbare-
VOLUME 107, NUMBER 2 411
ly projecting posteriorly between intema- riorly between intemasals; its length from
sals; 5) dorsal surfaces ofbody and ofhead above about ^i its distance from frontal;
uniform iridescent black; 6) venter white intemasalslarge, roundedanteriorly, slight-
withblackbandsonposterioredgesofscutes. ly shorter than suture with prefrontal; pre-
Diagnosis.—The new form is a member frontals short, their median suture about %
ofthe sieboldi group (Downs 1967), previ- length offrontal; frontal slightly wider than
ouslyrepresentedby 12 speciesrangingfrom long, quadrangular, incontactwithprefron-
MexicotoColombiaandincludingfourthat tals, supraoculars, and parietals, distinctly
occur in Costa Rica and Panama. Geophis angulate anteriorly; parietals moderately
talamancae may be distinguished from G. long, broad, their median suture almost
brachycephalus by having the dorsal scales equal to length offrontal; parietal does not
ontheanteriorhalfofthe body smooth and contact prefrontal above middle of orbit,
a uniform dorsal coloration (in brachyceph- but meets the supraocular and postocular
alus the dorsal scales are keeled except on scales. There is one postocular and one su-
the neck and there is often a distinct dorsal praocularscaleoneachsideofthehead(Fig.
patternoflight, usuallyred,bars, spotsand/ 1).
or stripes). The new form differs from both Nasal divided, postnasal about the same
Geophis zeledoni and G. hoffmanni in the sizeasprenasal,theircombinedlengthabout
keeling ofthe dorsal scales since these two 70% length ofloreal; loreal relatively long,
formshavekeelsonlyondorsalscalesabove slightlymorethan Vilengthofsnout, slightly
the vent. Unlike G. nigroalbus, which has more than 2 times eye diameter; eye small,
thepostocularandsupraocularseparatedby contained about 4'/3 times in snout length
an anterior projection of the parietal, the (tip ofsnout to anterior border ofeye), its
supraocular is in broad contact with the vertical diameter about equal to distance
postocular in G. talamancae. The new spe- from supralabials; supralabials 6-6, 3 and 4
cies is distinguished from G. betaniensis of in contact with orbit on both sides, 5th in
west-central Colombia (features for that contact with parietal; anterior temporal di-
form in parentheses) by having keeled pos- rectly above 6th supralabial, not fusedwith
terior dorsal scales (smooth dorsal scales) nuchals along parietal margin.
and one (two) postocular. Finally, it differs Mental rounded anteriorly, definitely
most obviously from the several species of broader than long, separated from chin
the G. championi group, all of which are shields by first pair ofinfralabials; infrala-
endemic to Costa Rica and/or Panama, in bials6-6,first3incontactwithanteriorchin
the shape of the head and associated fea- shields; anterior chin shields slightly longer
tures of scutellation. Geophis talamancae than broad, longer than posterior chin
has an elongate snout that is rounded in shields; posteriorchin shields short, in con-
dorsal outline, a rostral that barely extends tact anteriorly, diverging posteriorly; 3 gu-
posteriorly between the intemasals, and a lars separate chin shields from first ventral.
shortpostnasalthatishigherthanwide(Fig. Dorsal scale rows 15-15-15, keeled on
1). In the four members of the championi posterior half of body and tail; posterior
group {G. championi, G. downsi, G. god- dorsalscaleswithoutdiscernibleapicalpits.
mani, and G. ruthveni), the elongate snout Ventrals 138; anal entire; subcaudals 33.
is pointed, the rostral separates the inter- Ventrals + subcaudals 171. Standardlength
nasalsformuchoftheirlengthandthepost- (snout-to-vent) 185 mm, taillength 33 mm;
nasal is broad, the width being at least 75% tail length 16 percent oftotal length.
ofits height. Coloration.—Dorsal surfaces ofheadand
General characteristics.—Yiedid not dis- body uniform dark charcoal grey to black.
tinct from neck; snout elongate, rounded in Head color extends ventrally to supralabi-
dorsal profile; rostral not extending poste- als, infralabials, mental, and chin shields.
412 PROCEEDINGS OFTHE BIOLOGICALSOCIETY OFWASHINGTON
Fig. 1. SemidiagrammaticrepresentationofA)dorsalandB)lateralheadscutellation fortheholotype(CRE
5343) ofGeophis talamancae.
VOLUME 107, NUMBER 2 413
Gular area immaculate creamy white, be- rows; nopostocular, no supraocular, andno
coming flecked with black on first ventral temporal scales. Thenumberofventralsfor
and becoming progressively more flecked the three males (CRE 5344, 5319, 5072)
along anterior edge of scutes, until only a ranges from 139-141; subcaudals 34-38;
verythinwhiteposteriorborderremainson ventrals + subcaudals 173-179. The single
scutes near vent. Subcaudals completely female specimen (CRE 5337) has 140 ven-
black, without white markings. trals, 27 subcaudals, and 167 ventral + sub-
Distribution.—¥j\o-wnonlyfromthetype caudals. These valuesdo not differsubstan-
locality in the Lower Montane Rainforest tiallyfromthoseofspecimensfromthenorth
(Holdridge 1967, Tosi 1969) in the Cordil- in Costa Rica contra Downs' (1967) pre-
lera de Talamanca of Costa Rica near the diction. Geographical variation in G. god-
m
Panama border at 1800 elevation. maniexists,however, intheamountofven-
Remarks.—The type specimen was col- tral pigmentation between those specimens
lected from beneath a series of saplings from the area ofthe Barva-Poas volcanoes
whose roots were enclosed in plastic bags (venter almost uniformly bright yellow in
that had recently (within 4 months) been color) and those from Volcan Turrialba
transported frofti the region of the central south through the Cordillera de Talamanca
Cordillera de Talamanca along the Carre- to Las Tablas (bright yellow color ofventer
tera Interamericana, about 100 km north- limited to anterior edge ofscutes, posterior
west of the type locality. There is a slight edge black). It is clear from the differences
possibility that this snake might have been inventralcolorthattheescapedsnakemen-
brought to the Las Tablas area in this ship- tioned above was not G. godmani.
ment. However, a second specimen prob- Relationships.—The, new species is re-
ably ofthe same species (white belly with ferredtothe Geophissieboldigroup (Downs
distinct black bands on ventral scutes, uni- 1967) on the following basis: snout long,
form black dorsum) was collected from the projecting well beyond lowerjaw, rounded
Las Tablas area earlier in the year but es- in dorsal outline; rostral not produced pos-
capedbeforeanaccurateidentificationcould teriorly between internasals; internasals
be made. short, theirgreatestlength 33-62%ofsuture
FourspecimensofGeophisgodmaniwere between prefrontals; postnasal short, width
alsocollectedfromtheLasTablasarea, rep- about 50% ofheight; prefrontalsand loreals
resenting an intermediate population be- elongate; no anterior temporal; rounded
tween the two previously known but dis- mental; maxillaryextendsforwardtosuture
junct localities: a population from the betweensecondandthirdsupralabials, with
Cordillera Central and extreme northern 14subequalteeth,tipofmaxillarytoothless;
edgeoftheCordilleradeTalamancainCos- posteriorendofmaxillarytaperingtoablunt
ta Rica, and a population 250 km ESE of point.
Las Tablas on Volcan Baru in Chiriqui, The sieboldi group as understood by
Panama. The Panamanian specimens are Downs (1967) in his generic revision in-
representedonlybyheadsandnecks(Downs cluded four Mexican species {Geophis pe-
1967) so variation in ventral and subcaudal tersi, G. russatus, G. sallei, and G. sieboldi),
counts from the southern part ofthe range oneGuatemalan form{G. nasalis), oneNic-
was unknown. Because G. brachycephalus araguan endemic (G. dunni) and G. brachy-
and G. hojfmannihave distinctlylowerseg- cephalus(Costa Rica to Colombia), G. hoff-
mentalcountsonVolcanBaruthaninCosta manni (Honduras to western Panama), G.
Rica, Downs (1967) predicted that Pana- nigroalbus (eastern Panama to Colombia)
manian G. godmani would vary similarly. and G. zeledoni (Costa Rica). Downs pro-
All four specimens have 15-15-15 scale vided detaileddescriptions ofmost ofthese
414 PROCEEDINGS OFTHE BIOLOGICALSOCIETY OFWASHINGTON
forms but gave belated recognition to G. (rounded). These differences clearly pre-
nigroalbusand G. russatusonlyin footnotes clude inclusion of G. betaniensis in the
(p. 146 and p. 138, respectively). Campbell championi group.
andMurphy(1977)addedanotherMexican Comparison ofthe featuresofheadshape
species (G. pyburni) to the group. Within andscutellation o^Geophisbetaniensiswith
the genus, G. talamancae most closely re- those ofthe other speciesgroups ofGeophis
sembles G. nigroalbus but differs most ob- (Downs 1967) show a complete concor-
viously in the relation ofthe parietal to the dance between the Colombian species and
supraocularandpostocular(borderingthem members of the sieboldi group (see list of
posteriorly in talamancae, separating them characteristics at the beginning ofthis sec-
in nigroalbus). tion). In terms of skeletal and dentitional
Restrepo & Wright (1987) on the occa- features the championi and sieboldi groups
sion ofdescribing Geophis betaniensis from areverysimilarexceptthatinthelatterthere
Colombia expressed difficulty in accepting is no tooth on the tip ofthe maxillary (pres-
Downs' (1967) definitions ofspeciesgroups ent in the former) andthe hemipenes ofthe
and referred their new form to the cham- championi group differ in lacking capita-
pioni group. This decision was reached in tion. Unfortunately, features of the hemi-
part because G. betaniensis keyed out to G. penes were not included by Restrepo &
championi in Downs' key (couplet 29) to Wright (1987) in their original description
the genus. When they used Savage's (1981) because the only specimens referred to G.
key to Costa Rican and Panamanian Geo- betaniensis are both females. Nevertheless
phis, theyreachedacouplet(number4)that webelievethatevidencefromphysiognomy
distinguishedbetween G. hoffmanniand G. (general shape ofthe head) and scutellation
zeledoni {sieboldi group species) and this support the inclusion of G. betaniensis in
seems to be the basis for their puzzlement the sieboldi group.
over species group definitions. BecauseColombianspeciesofGeophisare
Bothkeys(Downs 1967, Savage 1981)are sympatricwithmembersofthe superficially
artificial ones based upon the most obvious similar genus Atractus, another fossorial
characters of the included species and are group, Restrepo & Wright (1987) discussed
designed for field identifications. No at- features of external morphology that may
tempt was made by either author to design be utilizedtodistinguishbetweenthem. Af-
akeyinwhich presumablyrelatedform(i.e., ter some discussion with Frances J. Irish,
members of the same species group) were who is undertaking a systematic revision of
placed together. Atractus, they concluded that the presence
Downs (1967), contrary to Restrepo & (inAtractus) and absence (in Geophis) ofan
Wright (1987), provided unambiguous def- anterior temporal scale and the number of
initions ofthe seven species groups that he chin shields (two pairs in Geophis and one
recognizedwithin Geophis. Members ofthe pair in Atractus) are diagnostic for those
championi group differ from G. betaniensis species found in Central and South Amer-
(features for that species in parentheses) in ica.
the following characteristics: snout elon- Unfortunately,thesituationismorecom-
gate, pointed (rounded); rostral produced plicated than these authors suggest. As
posteriorlybetween internasals (barely pro- pointed out by Savage (1960) and Downs
jecting between internasals); internasals (1967), presence or absence ofthe anterior
elongate, greatest length 67-100% of pre- temporal exhibits both interspecific and
frontal suture (50%); postnasal long, width some intraspecific variability in both gen-
atleast 75%ofheight(postnasal short,width era; those Geophis characteristically having
about 50% of height); mental acuminose an anterior temporal are confined to Mex-
VOLUME 107, NUMBER 2 415
Fig. 2. Diagrammaticdifferences in chin shields between A) Geophisand B)Atractus.
ico, and most examples ofAtractus consis- 2a. Two postoculars
tently have one. G. betaniensis (Colombia)
Savage (1960) had previously noted that 2b. One postocular 3
Geophis and Atractus from the area ofgeo- 3a. Uppermost dorsal scales keeled
graphic overlap in Panama and Colombia at least on posterior halfofbody
could be distinguished on the basis of the and tail 4
chin shield feature. Downs (1967) however, 3b. Dorsal and caudal scales smooth
questionedthe utilityofthischaractersince orsmoothexceptforsomefaintly
it isdifficultin somecasestodistinguishthe keeled scales above vent 8
posteriorchinshieldfromtheadjacentgular 4a. Dorsal scales on body (exclusive
scales in Geophis, which approaches the ofneck) and tail distinctly keeled 5
condition found in Atractus. Nevertheless, 4b. Dorsal scales on anterior halfof
although the posterior pair ofchin shields body smooth 6
are often small and usually separated by a 5a. Dorsal scales in 15 rows; dorsum
mediangularscale, there is noambiguity in dark, often with light lateral
using this feature to separate lower Central blotches, crossbands, or stripes
.
and SouthAmerican GeophisfromAtractus .G. brachycephalus (Costa Rica to
. .
(Fig. 2). Panama)
5b. Dorsal scales in 17 rows; dorsum
Key to Species ofGeophis from Lower light with dark blotches or sad-
Central America and Colombia dles G. dunni (Nicaragua)
6a. Postocular and supraocular in
la. Supraocular shields present .... 2 contact, excluding parietal from
lb. No supraocular scales 10 margin or orbit 7
416 PROCEEDINGS OFTHE BIOLOGICALSOCIETYOFWASHINGTON
6b. Postocular and supraocular sep- Biosphere Reserve, and to Marybel Soto
arated by extension of parietal Ramirez of the Organization for Tropical
that meets orbit Studies forexpeditingpermits. David Auth
G. nigroalbus (Colombia) (Florida Museum ofNatural History) pro-
7a. Snout pointed; rostral markedly vided specimens for comparison. We are
producedposteriorlybetween in- grateful to M. Donnelly for comments on
temasals; mental pointed themanuscriptandtoV. Sosaforproviding
G. ruthveni (Costa Rica) aSpanishtranslation. KRL'sfieldworkwas
7b. Snout rounded; rostral barely supported by the American Society ofIch-
producedposteriorlybetween in- thyologistsandHerpetologists' GaigeFund,
ternasals; mental rounded Society for the Study of Amphibians and
G. talamancae (Costa Rica) Reptiles Grants-in-Herpetology, Organiza-
8a. Five or fewer supralabials tion for Tropical Studies Pew/Mellon post-
G. hoffmani (Honduras to Panama) course grant. University ofMiami Tropical
.
8b. Six or more supralabials 9 Biology Fellowship, American Museum of
9a. Snout pointed; rostral markedly NaturalHistoryRooseveltFund,Explorer's
producedposteriorlybetween in- Club, andtheNational Geographic Society.
ternasals; mental pointed ante-
riorly; ventrals plus subcaudals
Literature Cited
156-158 G. championi (Panama)
. .
9b. Snout rounded; rostral barely Campbell,J.A.,&J.B.Murphy. 1977. Anewspecies
producedposteriorlybetween in- ofGeophis(Reptilia,Serpentes,Colubridae)from
ternasals; mental rounded; ven- the Sierra de Coalcoman, Michoacan, Mexi-
trals plus subcaudals 180-191 . Downs,coF..—L.Jou1r9n6a7l.ofInHterrapgeenteorliocgryel1a1t:i3o9ns7h-i4p0s3.among
G. zeledoni (Costa Rica) colubridsnakesofthegenusGeophisWagler.—
10a. Uppermost dorsal scales keeled Miscellaneous Publications ofthe Museum of
atleastonposteriorthirdofbody Zoology ofthe University ofMichigan 131:1-^^-1B
and on tail; ventrals 122-133; 193.
subcaudals 41-46 Holdridge, L. R. 1967. Life zone ecology. 2nd ed.
Tropical ScienceCenter, San Jose, Costa Rica.
G. downsi (Costa Rica) Restrepo,J.H.,&J.W.Wright. 1987. Anewspecies
10b. Dorsal scales smooth; ventrals ofthe colubrid snake genus Geophis from Co-
132-145; subcaudals 26-36 lombia.—Journal ofHerpetology 21:191-196.
G. godmani (Costa Rica to Panama) Savage, J. M. 1960. A revision ofthe Ecuadorian
snakes of the colubrid genus ^rrac/wi.—Mis-
Acknowledgments cellaneous Publications ofthe Museum ofZo-
Wewouldlike to thankthe family ofMi- olo1g9y8,1.UniNveerwsistpyecoifesMiocfhtihgeansec1r1e2t:i1v-e86c.olubrid
.
guel Sandi C. for their assistance to KRL. snakegenusGeophisfromCostaRica.—Copeia
We would also like to thank Juan Diego 1981:549-553.
Alfaroofthe Reserva BiosferaAmistadand Tosi, J. A., Jr. 1969. Mapa Ecologico. Tropical Sci-
ence Center, SanJose, Costa Rica.
Lie. Miguel Rodriguez R. ofthe Servicio de
Parques Nacionales del Ministerio de Re-
cursosNaturales, Energia, y MinasdeCosta DepartmentofBiology,UniversityofMi-
Rica forissuingpermits forworkwithin the ami, P.O. Box 2491 18, Coral Gables, Flor-
Zona Protectora Las Tablas ofthe Amistad ida 33124, U.S.A.