HARVARD UNIVERSITY

Ernst Mayr Library

of the Museum of

Comparative Zoology

^^^ 4 2006

PROCEEDINGS

MCZ

LIBRARY

of the

San Diego Society of Natural Histor)0CT 1 5 1990

Founded 1874

HARVARD

UNIVERSITY

Number 4

16 September IWO

A New Long-Nosed Snake (Rhinocheilus lecontei)

from Isia Cerralvo, Baja California Sur, Mexico

L. Lee Grismer

Department of Biology, San Diego State University. San Diego, California 92182, USA

ABSTRACT. — A population of Rhinocheilus lecontei from Isia Cerralvo, Baja California Sur, Mexico (previously included in R. I. lecontei), is

described here as a new subspecies based partly on its possession of uniquely shaped loreal and temporal scales, shallow dorsal body blotches, and

large size. It is most closely related to R. I. antonii of northwestern Mexico and probably arrived on Isia Cerralvo as the result of a relatively recent

overwater dispersal.

RESUMEN. — Una poblacion de Rhinocheilus lecontei de Isia Cerralvo. Baja California del Sur, Mexico anteriormente reconocido como R. I.

lecontei. se describe aqui como una subespecie nueva. R. I. ctheridgei. en honor de Richard E. Etheridge. Rhinocheilus I. etlwriclgei esta mas

relacionada aR.l. antonii de noroeste Mexico costero y probablemente Uego a Isla Cerralvo via un dispersulo reciente a traves el Golfo de California.

INTRODUCTION

The long-nosed snake. Rhinocheilus lecontei. currently consists

of three subspecies: R. I. antonii. which ranges from southern

Nayarit to northern Sonora, Mexico, west of the Sierra Madre

Occidental; R. I. tessellattis. ranging from southern San Luis Potosi

in central Mexico north to southwestern Kansas; and R. I. lecontei.

ranging from eastern Arizona and western Utah to coastal Califor-

nia and south to northern Sonora and northern Baja California,

Mexico. In Baja California Norte (BCN). R. I. lecontei has been

reported as far south as Mision San Borja, approximately 500 km

south of the international border. It is also known from a disjunct

population on Isla Cerralvo, Baja California Sur (BCS) (Medica

1975). The presence of/?. /. lecontei on the Baja California penin-

sula presumably led Soule and Sloan (1966) to consider the Isla

Cerralvo population (known at the time from a single specimen) as

R. I. lecontei, although it occurs 800 km south of the nearest known

peninsular locality.

The genus Rhinocheilus is notably constant in scalation and

variable in color pattern ( Klauber, 1 94 1 ). It is peculiar among North

American colubrids in that it has a characteristic color pattern

inversion or transposition where the centers of the scales in the

lateral portions of the alternating red and black bands are colored

black or reddish, respectively (Fig. I). Rhinocheilus lecontei

tessellatns and R. I. lecontei illustrate this character the best,

whereas in R. I. antonii, color pattern transposition is sometimes

weak. In morphology the subspecies are rather similar except for

the shape of the snout (Klauber, 1941 ). Rhinocheilus. I. tessellatns

has a sharp upturned snout resulting from an enlarged rostral scale.

In R. I. antonii this characteristic is similar (Fig. 2) but less pro-

nounced. In R. I. lecontei. the rostral scale is enlarged but not up-

turned (Fig. 2). Klauber (1941) characterized the subspecies as

follows: R, I. antonii has elongate dark body blotches that usually

number less than 17, a moderately upturned snout, and little in the

way of color pattern transposition; R. I. tessellatns has an extensive

amount of color pattern transposition, a sharply upturned snout, and

more than 17 dark body blotches; R. I. lecontei has at least 16 dark

body blotches, color pattern transpositions, but no upturned snout.

I have obtained four additional specimens from Isla Cerralvo

and find them sufficiently distinct in morphology and color pattern

to warrant a reexamination of this population's relationships and

taxonomic allocation.

MATERIALS AND METHODS

On 14 and 15 June 1988 I visited Arroyo Viejos at the south-

western tip of Isla Cerralvo opposite the village of El Sargento on

the peninsula. Here, two specimens of Rhinocheilus lecontei were

collected between 2230 and 0100 hours. These specimens and two

others previously collected from this arroyo (Soule and Sloan,

1966, and see below) were compared to the data of Klauber ( 1941 )

and to preserved specimens from throughout the range of/?, lecontei

representing all of the known subspecies (Appendix I). One of the

two previously collected (on 26 April 1988) was lost in transit from

the Hospital Militar de La Paz (HMLP) to the San Diego Natural

History Museum but not before it was examined and photographed.

It is referred to as HMLP 27.37.

All scale counts (ventrals, subcaudals, dorsals, supralabials, and

infralabials) and body and caudal blotch counts (from both living

and preserved specimens) were taken according to the methods of

Klauber ( 1941 ). The shapes of the rostral, frontal, loreal, and tem-

poral scales were compared. Comparisons of coloration included

degree of red on the head, black on the supralabial scales, presence

L. Lee Grismer

Figure 1. Three specimens ol RInnocliciliis lecontei elheridxei ssp nov. Upper, hololype. SDSNH 66294; middle, paratype, SDSNH 66309; lower,

HMLP 2737.

Long-Nosed Snake Irom Isia Ccrralvo

Figure 2. Side view of heads of Rluiuicheilus leionrei ankinii (upper,

LACM 125584). holotype of R. I. etherid^ei ssp. nov. (middle, SDSNH

66294). and R. I. Iccontei (lower, SDSNH 16028). Bar equals 2 cm.

or absence of ventral mottling, and presence or absence of caudal

color transpositions in the red bands. Also compared were tongue

coloration and total length.

RESULTS

Klauber (1941) noted that the rostral scales of Rhinocheilus

lecontei tessellatiis and fi. I. antonii are much more prominent and

protuberant than that o{ R. I. lecontei. He noted also that the edges

of the rostral scale in R. I. tessetlatus and some R. I. anumii are

raised above those of adjacent scales. The rostral of the Isla Cerralvo

population is similarly shaped (Fig. 2). In the Isla Cerralvo popu-

lation, the rostral also extends posteriorly for more than one-half the

length of the intemasals, and in one specimen, HMLP 2737, it

almo.st completely separated them (Fig. 1). Klauber (1941) noted

that the rostral extended farther posteriorly in R. I. tessellatiis than

in R. I. lecontei. but in the specimens 1 examined, their conditions

were nearly equal. In roughly 38% of the R. I. antonii 1 examined,

the rostral separated the intemasals for over one-half their length.

The anterior end of the frontal scale in the Isla Cerralvo popula-

tion tends to indent more deeply into the prefrontals than does that

of Rhinocheilus lecontei lecontei or R. I. antonii. In the latter, the

frontal tends to have a straight anterior margin. Klauber (1941)

noted that a deeply indenting frontal scale occurs in R. I. tessellatus,

but 1 found it in less than one-half of the specimens I examined.

Klauber (1941) noted that the posterior edge of the loreal in

Rhinocheilus lecontei tessellatiis is more vertical than that of R. I.

lecontei. This difference results from the difference m height of the

loreal scales. The loreal scale of R. I. tes.sellatiis is higher, resulting

in less of an anterior inclination of the posterior edge as well as a

less rectangular shape of the entire scale. This condition is exag-

gerated in the Isla Cerralvo population, in which the loreal is nearly

square (Fig. 2). Also in the Isla Cerralvo population, the posterior

edge is longer than the anterior edge and gives the dorsal margin a

forward tilt, a condition not observed in the other subspecies.

Klauber ( 1941 ) staled that R. I. antonii has a rectangular loreal, and

in the material I examined (Appendix I), I found its loreal shape like

that of R. I. te.s.sellaliis (Fig. 2). All but one (SDSNH 34.'i3.'S) R. I.

lecontei examined had narrow, rectangular loreals. SDSNH 34535

approached the condition seen in R. I. antonii and R. I. tes.sellatiis.

The most anterior temporal scales in the Isla Cerralvo popula-

tion are only slightly larger than those more posterior (Fig. 2). In all

other subspecies the anterior temporals are elongate and much

larger than the posterior temporal .scales. Klauber ( 1941 ) noted, as I

did, that temporal scales of Rhinocheilus lecontei tessellatus tend to

be smaller than those ofR. I. lecontei; however, they are not as small

as those of the Isla Cerralvo population. Rhinocheilus I. antonii

resembles R. I. lecontei in having elongate anterior temporal scales.

Rhinocheilus lecontei antonii and the Isla Cerralvo population

have red tongues with gray tips. In R. I. tessellatus and R. I. lecontei,

the tongue is black with gray tips (Klauber, 1941). Klauber (1941)

stated that in R. I. claius (= lecontei). the tongue is black with light

tips and a red-brown base. I was unable to confinn this in either

preserved or living material.

Of 313 specimens of Rhinocheilus lecontei lecontei examined

by Klauber ( 1941 ), the total length of the largest specimen was 892

mm, and 19 specimens (6.0%) were over 800 mm in length. The

longest R. I. tessellatus reported by Klauber ( 1941 ) was 936 mm in

total length, and of his 79 specimens, nine ( 1 1.4%) were over 900

mm. Conant (1975) stated that adult R. I. tessellatus range from 560

to 810 mm in length but listed a record individual at 1041 mm. The

largest R. I. antonii that I examined measured 1097 mm in total

length, and 1 1 specimens (9.0%) were over 900 mm long. Of the

four known specimens of the Isla Cerralvo population, CAS 98095

is 1246 mm. SDSNH 66294 is 1166 mm, SDSNH 66309 is 832

mm, and HMLP 2737 was 241 mm in total length. Therefore, the

largest known specimen of the Isla Cerralvo population is 354 mm

longer than the largest known R. I. lecontei and is similar to the

mainland Mexican forms in its large adult size. With such a small

sample size it is reasonable to assume that CAS 98095 and SDSNH

66294 are not the two largest individuals of the Isla Cerralvo

population and that additional material may prove to be larger.

The anterior portions of the frontal, prefrontals, nasals, and

rostral scales in the Isla Cerralvo population are heavily washed

with red-orange and dark only at the scale junctions (Fig. 1). A

similar condition occurs in Rhinocheilus lecontei tessetlatus. In R. I.

lecontei, the frontal is usually only cream colored on the edges, and

the prefrontals, nasals, and rostral are only occasionally red-orange.

The snout of R. I. antonii is heavily mottled, and the light areas are

also cream colored.

Klauber (1941) noted that all the supralabial scales of

Rhinocheilus lecontei lecontei are edged with black. 1 have con-

firmed this condition in the additional specimens from BCN that 1

examined, except one (SDSNH 42523) lacks such banding between

supralabials I and 2. Klauber (1941) reported the same condition

L. Lee Grismer

for R. I. anlonii. though I found that some specimens tend to lack

bands between the anterior supralabials. In R. I. lesseUatus. banding

between the first four surpalabials ranges from absent to present,

and banding is absent in all Isla Cerralvo specimens (Fig. 1 ).

The Isla Cerralvo specimens do not difler greatly from the other

subspecies in the number of dark body or caudal blotches, although

they do tend to have more blotches than does RhiiuKheilus Iccoiuei

anlonii (Table 1 ). In the Isla Cerralvo specimens, the dark body

blotches rarely extend ventrally past the third or second dorsal scale

row. This leaves the ventrolateral surface of the body immaculate

(Fig. I, upper). In all other subspecies, the body blotches almost

always extend ventrally far enough to reach the lateral edges of the

ventral scales.

The Isla Cerralvo population lacks the color pattern transposi-

tion of black mottling in the red interspaces in the caudal region

(Fig. 1). Such a color transposition rarely occurs in Rhinoclicilus

lecontei anlonii and is present in all but one juvenile specimen o( R.

I. tessellatiis (SDSNH 33198; total length 278 mm). Caudal color

transposition is occasionally absent in hatchling and juvenile R. I.

lecontei. Klauber (1941) noted that color pattern transpositions are

absent in many juveniles but became frequent in progressively

larger specimens.

The venter in the Isla Cerralvo population is immaculate. This is

generally the case in Rhinocheihis lecontei tessellatiis except for

edgings on the lateral edges of the ventral scales by the black dorsal

blotches. The venters of R. I. lecontei and R. I. antonii are never

immaculate, and in the majority of/?. /. antonii the venter is heavily

marked.

From this analysis I believe the Isla Cerralvo population is

sufficiently distinct to warrant subspecific recognition and thus

propose the following new subspecies:

Rhinocheilus lecontei etheridi^ei new subspecies

Figures 1 and 2

Siii^gested common name. — Isla Cerralvo long-nosed snake.

Holotype.—^DSnn 66294; adult male, 1016 mm snout-to-

vent length (SVL); collected by Victor M. Velazquez, L. Lee

Grismer. and Mark A. Galvan on 14 June 1988 in Arroyo Viejos at

10 m in elevation on the southwestern end of Isla Cerralvo, Baja

Califomia Sur. Mexico.

Paratopes. — Two paratypes from same locality as holotype.

CAS 98095, adult male. 954 mm SVL, collected on 29 October

1961, and SDSNH 66309, adult male, 732 mm SVL. The lost fourth

specimen, HMLP 2737, is not considered part of the type series.

Diagnosis. — Rhinoclieilus lecontei elheridgei differs from all

other subspecies of R. lecontei by having ( 1) an enlarged, square

loreal scale with a forward-sloping dorsal margin; (2) shortened

anterior temporal scales (Fig. 2); (3) shallow dorsal body blotches

that do not extend onto the lateral edges of the ventral scales (Fig. 1,

upper); and (4) a much larger adult size. It differs further from R. I.

anlonii and R. I. lecontei in lacking darkened supralabial borders

anterior to the eyes (Fig. 1 ), from R. I. lecontei and R. I. tessellatiis

in having a red tongue, and from R. I. lecontei in having a greatly

enlarged rostral scale (Fig. 2).

Dislrihiilion. — Known only from the southwestern end of Isla

Cerralvo, Baja Califomia Sur, Mexico.

Description of holotype. — Adult male, 1016 mm SVL, 150 mm

tail length; body stout; head narrow and triangular, slightly distinct

from neck; snout sharply pointed in lateral aspect; diameter of eye

68% of distance from anterior edge of orbit to nostril; pupil round.

Rostral enlarged, pointed, protuberant, distinctly elevated from

adjacent scales, and concave below with dorsal process extending

Table 1. Ranges, means Cv), and standard errors (SE) of scale, dark body blotch, and

dark caudal blotch counts of the four subspecies of Rhinocheilus lecontei.

'HMLP 2737 included.

Long-Nosed Snake from Isla Cerralvo

posteriorly greater than one-half the length of the intemasals. Ros-

tral followed dorsoposteriorly in succession by a pair of triangular

intemasals meeting posteriorly on the midline, a pair of wedge-

shaped prefrontals curving ventrally over the rostrum and contact-

ing medially, a hexagonal frontal longer than wide and widest

anteriorly where it indents deeply mto the prefrontals, and a pair of

elongate parietals that are widest anteriorly, meet broadly on the

midline, and are separated anteriorly by the frontal. On each side of

frontal is an elongate supraocular that is pointed anteriorly. Fol-

lowing rostral posterolaterally in succession are a prenasal ( 1-1 ), a

postnasal ( 1-1 ). a large square loreal with a forward-sloping dorsal

margin ( 1- 1 ), and a moderate-sized preocular ( I - 1 ). Posterior to eye

are a pair of small equally sized postoculars (2-2) followed by

temporal scales (2-(-3-2-t-.^). anterior temporal scales only slightly

larger than those posteriorly. Supralabials 8-8 increasing in size

posteriorly. Infralabials 9-9. first pair contacting medially; second

infralabial one-half size of first and third, fifth infralabial largest;

infralabials decrease in size from this point posteriorly. Mental

small, triangular, and completely enclosed within first pair of

infralabials which are followed by an elongate pair of chin shields

that make broad medial contact and contact the second and third

infralabials laterally. Dorsal scales smooth. 25 rows one head length

behind depression of neck. 23 at midbody. and 19 one head length

anterior to vent; 212 ventrals. lateral portions curving dorsally and

easily visible on side of body. Anal plate entire; subcaudals 52,

34th. and last 15 divided, the rest single.

Cotonilion ofholotype in life. — Head suffused with red-orange,

frontal and parietals black centrally and red-orange laterally.

Temporals and adjacent posterior dorsals have red-orange centers

and dark edges; supralabial banding restricted to edges of

supralabials 4-8. Pupils red; tongue bright red with gray tips. Body

markings consist of 24 black blotches that taper ventrally and reach

to the second dorsal scale row at most. The four to seven most

ventral scale rows of the dark dorsal blotches suffused centrally

with cream; secondary blotches usually present between main body

blotches on first to fifth scale rows. Twenty-four red-orange

interspaces on body with dark suffusion in scale centers of the most

ventral five to seven rows of the red-orange interspace; interspace

solid red-orange medially. Tail with seven black blotches showing

same color transposition as in body blotches; eight red-orange

caudal interspaces almost completely devoid of dark suffusion.

Ventrum cream-yellow and immaculate; ventral color usually ex-

tending dorsally to middle of fourth dorsal scale row.

Variation. — The paratypes approximate the holotype very

closely in scale morphology; the only noteworthy difference is that

the posterior extension of the rostral scale in HMLP 2737 almost

completely separated the intemasals (Fig. I. lower).

CAS 98095 is nearly identical to the holoype in coloration. The

same is tme for SDSNH 66309 except that its dorsal interspaces are

narrower (Fig. 1 ). HMLP 2737 varied widely in both coloration and

dorsal blotching (Fig. I ). The dorsal blotches of the central third of

the body formed a reticulated pattem and their color transposition

was more prominent centrally. Also, the interspaces on its body and

tail were light orange instead of red-orange. The light coloration on

its head was cream-yellow and the iris was silver-gray instead of

red-orange. HMLP 2737 was only 241 mm in total length, sug-

gesting that these colors may change with age. Klauber (1941)

noted an ontogenetic change in coloration in the other subspecies.

Etymology. — It is with great honor and pleasure that I name this

population after Richard E. Etheridge in recognition of his early

work on Isla Cerralvo (Etheridge. 1961 ).

Ecological notes. — The first specimen oi Rhinocheilus lecontei

etheridgei to be collected (CAS 98095 ) was found on 29 October

1961 (Soule and Sloan, 1966) during the day coiled beneath a bush

in the shade eating a Dipsosaurus dorsalis lucasensis (Banks and

Famier. 1963). HMLP 2737 was collected on 26 April 1988 at 1100

hours on coastal dunes at the mouth of Arroyo Viejos. SDSNH

66309 was collected on 14 June 1988 at 0100 hours in Arroyo

Viejos approximately 1 km from its mouth. This specimen was

crawling in the arroyo bottom on loose gravel. SDSNH 66294 was

collected on the same date as SDSNH 66309 at 2230 hours and was

found slightly over 2 meters above the ground in an elephant tree

{BurseiLi miciophylla). Earlier that evening, several individuals of

the lizard Salor grandaevus were observed roosting in the branches

of B. miciophylla and other brush. Other specimens of S.

grandaevus were observed out in the open on the arroyo bottom and

retreated into the lower branches of the brush when frightened by

our lights. Arboreal activities by Rhinocheilus have never been re-

ported. Presumably this snake was foraging for S. grandaevus,

though its eyes were opaque when it was collected.

DISCUSSION

Relationships. — Most often, subspecies are the result of subjec-

tive designation of sections of a more widely ranging continuous

population (Frost and Hillis. 1990) responding differently to re-

gional environmental constraints. Although each of the continental

subspecies of Rhinocheilus lecontei can be clearly diagnosed from

one another, none is demonstrably monophyletic. On the other

hand, there is no evidence suggesting that they are paraphyletic and

thus a designation as metataxa (Gauthier et al., 1988) for these

subspecies is appropriate.

Rhinocheilus lecontei etheridgei has the greatly enlarged and

protuberant rostral scale characteristic of R. I. antonii and R. I.

tes.sellatus (Fig. 2). This character varies clinally (Klauber. 1941 ),

the scale being intermediate in size where R. I. lecontei intergrades

narrowly with R. I. antonii and R. t. lessellatus in northern Sonora

and southeastem Arizona, respectively (Medica. 1975). The ab-

sence of this feature in species of the related colubrid genera

Lampropeltis. Pituophis. Elaphe. Cemophora. Arizona, and

Phyllorhynchus (Dessauer. 1967; Underwood. 1967; Bury et al.

1970). considered here as outgroups. suggests that enlargement of

the rostral is a derived condition. Thus. R. I. etheridgei. R. I. antonii,

and R. I. tessellatus form a clade exclusive of R. I. lecontei. To as-

sess relationships within this clade. R. I. lecontei can be used as the

functional first outgroup (Watrous and Wheeler, 1981). Both R. I.

antonii and R. I. etheridgei have red tongues and lack color trans-

positions in the caudal interspaces (see above for variation), char-

acter states not shared with R. I. tessellatus or the outgroup R. I.

lecontei. suggesting that the former two are sister taxa (Fig. 3).

Although R. I. etheridgei is more similar to R. I. tes.sellatus in

overall color pattem than it is to R. I. antonii (Table 2). 1 prefer to

base relationships on the presence of shared derived character

states. Rhinocheilus I. etheridgei has the autapomorphic states of an

enlarged square loreal. shortened anterior temporals, and shallow

dorsal body blotches. The weakness here is that only one outgroup

could be employed and that additional outgroups could demonstrate

that these character states are equivocal. Given the poor resolution

of relationships among North American colubrid genera, however. I

believe this is the most reasonable estimate that can be made at this

point.

Biogeography. — Medica (1975) and Murphy and Ottley ( 1984)

followed Soule and Sloan (1966) and listed the Isla Cerralvo

population as Rhinocheilus lecontei lecontei. Medica ( 1975) stated

that R. lecontei will most likely be found to inhabit all of the Baja

California peninsula, and Murphy and Ottley ( 1984) suggested that

R. I. etheridgei is a peninsular derivative. 1 disagree with both

statements. It is likely R. I. lecontei ranges throughout the Sierra

San Borja. BCN. and even possibly the Sierra San Francisco. BCS.

as far south as the Magdelena Region, approximately 150 km south

L. Lee Grismer

lecoutei

tessellatus* antonii

etheridgei

■nlargcd square loreal;

shortened anterior temporals;

shallow dorsal body blotches

red tongue; no caudal

color transposition

greatly enlarged rostral

scale

Figure 3. Cladistic relationships of the subspecies of Rhiiiochciliis leconrei. Asterisks designate metataxa.

of its current southernmost record. However, its apparent absence

from heavily collected areas in the vicinity of San Ignacio, BCS, at

the northern edge of the Magdalena Region suggests it does not

occur there. Furthermore, I showed the Isia Cerralvo specimens

(while living) to many ranchers throughout BCS (especially in the

Cape Region) who have proven to be knowledgeable and reliable

sources in the past and none had any knowledge of this species.

Because Rhinocheilus Iccuniei e!heiidi;ei is related to rnainland

Mexican taxa and Isla Cerralvo is an old continental island derived

from southwestern Mexico about 10-14 million years ago (Gastil

and Jensky, 1973), the population may have originated through

either vicariance or overwater dispersal. If R. I. elheridgei is the

sister taxon of R. I. anlonli, as I propose, both must be of relatively

recent origin because these are the most recently derived lineages

within R. lecontei (Fig. 3). Furthermore, \{ R. I. antonii is not de-

monstrably monophyletic, it could serve as the potential ancestor of

R. I. elheridi^ei. Other snakes proposed to have evolved on the Cape

Block have diverged much more from their mainland Mexican

sister taxon, which occurs in southwestern Mexico near the pro-

posed point of origin of the Cape Block (Grismer, 1990; Murphy,

1983). Overwater dispersals of mainland Mexican taxa to islands in

the Gulf of California that are geographically closer to the penin-

sula are not uncommon. Other insular taxa derived from mainland

Mexican stock that must have arrived by overwater dispersal are

Cnemiilophiinis ligris calcilinensis (Walker and Maslin, 1981 ) and

Lampropellis ijerula splcndida (Blanney, 1977) of Isla Santa

Catalina, Crolahis atrox atrox of Isla Santa Cruz (Murphy and

Ottley, 1984), and C. a. lortu^ensis of Isla Tortuga (Klauber, 1972).

APPENDIX I

Material of Rhini>chciliis lecontei Examined

Rhinocheilus lecontei antonii. — Sonora: LACM 7085, 9143.

9512, 27785-87, 37292-93, 51554, 192734-48, I1590-V08,

122376: SDSNH 3811, 18163. I8I74, 18175. 35914-15, 46085,

49552-53, 49913. Sinaloa: LACM 7055-84, 50907-09, 51557-58,

59126-27, 63459, 76594, 8658-59, 37323, 38199-201, 102712-

29, 115899-902, 121328-29, 125584-85, 136963; SDSNH 49554,

49572, 49572, 57008, 60489-90.

Rhinocheilus lecontei lecontei. — Baja California Norte: LACM

2660, 25077, 36576, 20821-22, 59125, 102709-11, 133919,

133921; MVZ

182121,189973, 189889, 189922. SDSNH 1689, 2257, 48147,

62225, 16028, 31450, 34003, .U535, 39705, 39706, 39940, 42094,

42176, 42439, 42543, 42632, 42747, 42989, 49571.

Rhinocheilus lecontei tessellatus. — New Mexico: SDSNH

25492, 40883, 32672. Texas: SDSNH 30420-22, 20513, 36171,

25523, 33198-200, 34548, 46180, 42484, 33395. Coahuila:

SDSNH 57025, 58402. Durango: SDSNH 49579. San Luis Potosi:

SDSNH 58396.

Table 2. Summary of diagnostic differences between the subspecies of Rhinocheilus

lecontei."

etheridgei

tessellatus

lecontei

Rostral enlarged

Long posterior extension of rostral

Frontal indenting deeply into prefrontals

Loreal enlarged and square''

Anterior temporals small'

Tongue red with gray tips

Adult total length > 1200 mm

Red-orange on rostrum

Intcr-supralabial banding

Body blotches shallow

Caudal color transposition in interspaces

Ventrutn immaculate

"+. character present; 0, character absent.

'Tendency toward condition of R. I. etheridf^ei in R. I. antonii and R. I. tessellatus.

Tendency toward condition of R. I. cthcndt^ei in R. I. tessellatus.

Long-Nosed Snake from Isia Cerralvo

Rhimicheilus lecimlei etheiidgei. — Baja California Sur: CAS

98095; HMLP 2737; SDSNH 66294. 66309.

ACKNOWLEDGMENTS

For the loan of material I thank G. Pregill. San Diego Natural

History Museum (SDSNH). A. Leviton and J. Vindum. California

Academy of Sciences (CAS). J. W. Wright. Los Angeles County

Museum (LACM). and D. B. Wake. Museum of Vertebrate Zoology

(MVZ). The Isla Cerralvo specimens were collected under scien-

tific collecting pemiits issued to Lt. Victor M. Velazquez and L. Lee

Grismer by Jorge Rodriguez Reyes and Jose Luis Genel of the

Secretaria de Desarrollo Urbano y Ecologio (SEDUE). For com-

ments on the manuscript I thank R. E. Etheridge, J. Iverson. R A.

Medica. G. K. Pregill. S. Sweet. P. Unitl. and J. W. Wright.

LITERATURE CITED

Banks. R. C. and W. M. Famier. 1963. Observations on reptiles of

Cerralvo Island. Mexico. Herpelologica 18:246-250.

Blaney. R. M. 1977. Systematics of the common klngsnake.

Lcimpnipellis gelulus (Linnaeus). Tulane Studies in Zoology and

Botany 19:47-103.

Bury. R. B.. F. Grcss. and G. C. Gorman. 1970. Karyotypic survey of

some colubrid snakes of western North America. Herpelologica

16:461-466.

Conant. R. 197.'i. A Field Guide to Reptiles and Amphibians of Eastern

and Central North America. 2nd ed. Houghton Mifflin. Boston.

Dessauer. H. C. 1967. Molecular approach to the ta.xonomy of colubrid

snakes. Herpelologica 22:184-189.

Etheridge. R. 1961. Additions to the herpetological fauna of Isla

Cerralvo in Ihe Gulf of California. Mexico. Herpelologica

17:57-60.

Frost. D. R.. and D. M. llilhs. 1490. Species in concept and practice:

Hherpetological applications. Herpctologica 46:87-104.

Gaslil R. G.. and W. Jensky. 1973. Evidence for strike-slip displacement

beneath the Irans-Mexican volcanic belt. Pp. 171-1X0 in R. L.

Kovach and A. Nur (eds.). Proceedings of Ihe conference on tec-

Ionic problems of the San Andreas Fault system. Stanford Univer-

sity Publications in Geological Sciences 13.

Gauthier, J., R. Estes. and K. de Queiroz. 1988. A phylogenelic analysis

of Lepidosauromorpha. Pp. 1.5-98 in R. Estes and G. Pregill (eds.).

Phylogenetic Relationships of the Lizard Families. Stanford Uni-

versity Press. Stanford, California.

Grismer. L. L. 1990. Relationships, taxonomy, and biogeography of the

Maslicophis latentlis complex in Baja California. Mexico.

Herpelologica 46:66-77.

Klauber. L. M. 1941. The long-nosed snakes of the genus Rbinocheilus.

Transactions of the San Diego Society of Natural History

9:289-332. Medica. R A. 1975. Rlunocheilus. R. leamlei. Cata-

logue of American Amphibians and Reptiles: 175. Society for the

Study of Amphibians and Reptiles. New York.

Murphy. R. W. 1983. Paleobiogeography and genetic differentiation of

the Baja California herpetofauna. Occasional Papers of Ihe Cali-

fornia Academy of Sciences 137:1-48.

. and J. R. Ottley. 1984. Distribution of amphibians and reptiles

on islands in the Gulf of California. Annals of the Carnegie

Museum of Natural History 53:207-230.

Soule, M.. and A. J. Sloan. 1966. Biogeography and dislnbution of the

reptiles and amphibians on islands in the Gulf of California.

Mexico. Transactions of the San Diego Society of Natural History

14:137-156.

Underwood G. 1967. A Contribution to the Classification of Snakes.

British Museum (Natural History), London.

Walker. M. J., and P. Maslin. 1981. Systematics of Ihe Santa Catalina

whiptail [CnemiJophorus culalinensis) with reference to the

superspecies Cnemidiiphiinis lii^ris. American Midland Naturalist

105:84-92.

Watrous. L. E.. and Q. D. Wheeler 1981. The out-group comparison

method of character analysis. Systematic Zoology 30:1-11.