The distribution and variation of the shovel-nosed snake Chionactis palarostris with the description of a new subspecies from coastal ,

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Authors Blake, Richard Anthony, 1944-

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Link to Item http://hdl.handle.net/10150/566351 THE DISTRIBUTION AND VARIATION OF THE

SHOVEL-NOSED SNAKE CHIONACTIS PALAROSTRIS

WITH THE DESCRIPTION OF A NEW SUBSPECIES

FROM COASTAL SONORA, MEXICO

by

Richard Anthony Blake

A Thesis Submitted to the Faculty of the

DEPARTMENT OF BIOLOGICAL SCIENCES

In Partial Fulfillment of the Requirements For the Degree of

MASTER OF SCIENCE WITH A MAJOR IN ZOOLOGY

In the Graduate College

THE UNIVERSITY OF ARIZONA

1 9 7 0 STATEMENT BY AUTHOR

This thesis has been submitted in partial fulfillment of re­ quirements for an advanced degree at The University of Arizona and is deposited in the University Library to be made available to borrowers under rules of the Library.

Brief quotations from this thesis are allowable without special permission, provided that accurate acknowledgment of source is made. Requests for permission for extended quotation from or reproduction of this manuscript in whole or in part may be granted by the head of the major department or the Dean of the Graduate College when in his judg­ ment the proposed use of the material is in the interests of scholar­ ship. In all other instances, however, permission must be obtained from the author.

SIGNED/

APPROVAL BY THESIS DIRECTOR

This thesis has been approved on the date shown below:

/3/ M 7o_

C. H. Lowe Date Professor of Zoology ACKNOWLEDGMENTS

I am indebted to the following individuals and institutions for allowing me to examine the material in their care: Dr. Robert

C. Stebbins, University of California, Berkeley (MVZ); Mr. Merrit

S. Keasey, Arizona Sonora Desert Museum (ASDM); Dr. Ernest E. Williams,

Harvard University, Museum of Comparative Zoology (MCZ); Mr. Joseph F.

Copp, 1441 Muirlands Drive, La Jolla, California (JFC); Dr. Richard B.

Loomis, California State College at Long Beach (CSCLB); Dr. Charles H.

Lowe, University of Arizona (UAZ); Dr. John W. Wright, Los Angeles

County Museum of Natural History (LACM); and Dr. Hobart M. Smith, Uni­ versity of Illinois, Museum of Natural History (UIMNH). Special thanks to Drs. C. H. Lowe, J. W. Wright, R. B. Loomis and Mr. Robert L. Bezy for their help in the preparation of this manuscript is acknowledged.

I also appreciate the efforts of Mr. Lynn W. Robbins and Mr. John K.

Cross and others for their field assistance.

iii TABLE OF CONTENTS

Page

LIST OF ILLUSTRATIONS...... v

LIST OF T A B L E S ...... vi

ABSTRACT ...... vii

INTRODUCTION ...... ; : ...... 1

CHIONACTIS PALAROSTRIS (KLAUBER) ...... 3

D i a g n o s i s ...... 3

CHIONACTIS PALAROSTRIS PALAROSTRIS (KLAUBER) ...... 5

Diagnosis ...... 5 R e m a r k s ...... 5

CHIONACTIS PALAROSTRIS ORGANICA KLAUBER ...... 7

D i a g n o s i s ...... 7 R e m a r k s ...... ' ...... 7

CHIONACTIS PALAROSTRIS SERI, SUBSP. NOV...... 9

Holotype ...... Paratypes ......

Diagnosis ...... to t o t o Description of H o l o t y p e ...... 10 V a r i a t i o n ...... 16 H a b i t a t ...... 16 P r o b l e m s ...... & ...... 17

SPECIMENS EXAMINED ...... 18

Chionactis palarostris palafostfis, 23 ...... 18 Chlonactis palarostns organica, 2 4 ...... 18 ChionactisT palarostris seri, 14 ...... 19 Chionactis p_. organica x seri, 7 ...... 19

LITERATURE C I T E D ...... 20 iv LIST OF ILLUSTRATIONS

Figure Page

1. Variation in the number of ventrals plus caudals for four populations of Chionactis palarostris (above), and in the number of scales between the parietals and first body band (below). Vertical lines represent the sample mean, hori­ zontal lines, the range of variation and solid bar, the mean t\95 times the standard error of the m e a n ...... 11

2. Chionactis p. seri, female, SDSNH 45222, 10 miles east of Kino Bay, Sonora, Mexico. Photo by Ron Garrison, San Diego Zoo L a b ...... 12

3. Map of Sonora, Mexico and southern Arizona showing the distribution of the four populations of Chionactis palarostris ...... 13

v LIST OF TABLES

Table Page

1. Data for comparison of four populations of Chionactis palarostris ...... 14

2. Data for the thirteen paratypes of Chionactis 2. seri. Column numbers represent (1) number of scales between parietals and first band, (2) total number of bands, (3) number of complete bands, (4) number of ventral caudal scales, and (5) ratio ' midbody and interspace widths ...... 15

vi ABSTRACT

A comparison of samples of known populations of Chionactis palarostris (Klauber, 1937) indicates that it is desirable to recognize three subspecies: (X palarostris (Klauber, 1951), jx organica

(Klauber, 1951), and a new subspecies, C_. £. seri, from the coast of

Sonora, Mexico. Five characters were utilized: (1) the number of scales between the paired parietals and the first black band (parictal-

1st band), (2) the total number of black bands, (3) the percentage of black bands completely encircling the body, (4) the ventral + caudal counts (v + c), and (5) the relative widths of the mid-body black bands and the adj acent interspaces (bw/iw).

Chionactis |K palarostris differs from jx organica and jx seri by having more scales between the parietals and first band, a fewer number of bands, and a lower mid-body band and interspace widths ratio.

Chionactis jx organica differs from jx seri by having a higher mid-body band and interspaces widths ratio, a higher percentage of bands complete, and a lower ventral-caudal count.

Chionactis jx organica appears to be geographically isolated from both (% jx palarostris and £. ]x seri and has been recorded only from Organ Pipe Cactus National Monument, Pima County, Arizona.

Chionactis p. palarostris has been recorded between and

Guaymas, Sonora, Mexico. Chionactis p. seri has been recorded from Kino

Bay to 40 miles north of El Desemboque del Rio San Ignacio, between

vii viii

Kino Bay and Hermosillo, and 8-20 miles north of Hermosillo. Specimens recently collected near Altar, Sonora, seem to be intermediate between

C. £. organica and . seri. INTRODUCTION

Klauber (1937) described a new snake, Sonora palarostris, based on a single specimen reportedly collected five miles south of Magdalena,

Sonora, Mexico. Although this specimen resembled iS. occipitalis in con­ figuration, it had slightly fewer ventrals, fewer number of black bands on the body, and a different body pattern. Stickel (1941) examined a specimen of Sonora from the Costa Rica Ranch, 40 miles northwest of

Hermosillo, Sonora, having band counts intermediate between ZL occipi­ talis and S. palarostris described by Klauber. Stickel believed that additional intermediate specimens would be found in northwestern Sonora.

He therefore reduced £>. palarostris to the subspecific status of EL occipitalis palarostris. Stickel (1943) divided Sonora into two genera, re-establishing Chionactis Cope for £. occipitalis. Hensley (1950) reported several specimens as Chionactis occipitalis palarostris in Or­ gan Pipe National Monument, Pima County, Arizona. With several speci­ mens of £. o^. palarostris available, Klauber (1951) again examined the populations of Chionactis and found differences between (L o. palaros­ tris and the populations of CL occipitalis as well as differences between the populations of (L ck palarostris. Therefore, he proposed re-establishing (L palarostris (Klauber), applying the name C^, £. palarostris to the Sonoran population and erecting a new subspecies, C.

organica, for the Arizona population reported by Hensley (1950).

1 2

At the time of his work, Klauber had three specimens of (% £.• palarostris available to him.. One specimen from El Pocito (between

Hermosillo and Guaymas), Sonora, was similar to the. type specimen re­ portedly collected five miles south of Magdalena, Sonora. Both of these specimens were unlike the specimen collected on the Costa Rica

Ranch, which Stickel (1941) reported as an intermediate. Klauber (1951) suggested that additional collecting would be needed to establish the status of this specimen from the Costa Rica Ranch.

In recent years several collections of Chionactis have been made in the regions of Hermosillo, Guaymas and Kino Bay. The purpose of this investigation is to determine the status of the Costa Rica Ranch

specimen and to better define the distribution and variation of

Chionactis palarostris. CHIONACTIS PALAROSTRIS (KLAUBER)

Sonora palarostris Klauber, 1937:363

Sonora occipitalis palarostris: Stickel, 1941:135

Chionactis occipitalis, palarostris: Stickel, 1943:109

Chionactis palarostris palarostris: Klauber, 1951:141

Diagnosis

Chionactis palarostris differs from C. occipitalis^ by having a blunt, convex snout; fewer and wider bands; fewer ventrals and cau­ dal s; and a head crescent involving almost the entire surface of the parietals.

Chionactis palarostris characterized by black bands on creamy to white ground color; interspace saddles varying from red to orange, not interrupted at any point in series. A small percentage of specimens have black-brown maculations in interspace, usually not including en­ tire scale, rather just scale edges and restricted to lateral portions of interspace.

Scalation, excluding ventrals and caudals, similar to C^. occipi­ talis; 17-21 smooth scales at head decreasing to 15 at midbody and anus; paired parietals, supraoculars, prefrontals, internasals, postoculars,

and two paired chin shields; single frontal, rostral, loreal, mental, and

1. The circumstances surrounding the description and, therefore the status of Chionactis saxatilis (Funk, 1967) are of such question that it is not recognized herein.

3 usually single preocular; six to eight supra and infralabials; anal divided.

Head crescent usually involving two-thirds of frontal and

supraoculars, usually, all of parietals and postoculars, and often

including portions of preoculars, loreal, temporals and supralabials. CHIONACTIS PALAROSTRIS PALAROSTRIS (KLAUBER)

Sonora palarostris Klauber, 1937:363

Sonora occipitalis palarostris: Stickel, 1941:135

Chionactis occipitalis palarostris: Stickel, 1943:109

Chionactis palarostris palarostris: Klauber, 1951:141

Diagnosis

Scales between paired parietals and first band 8-20, mean 11.9

(+1.45); bands (body plus tail including black tip if present) 11-18, mean 13.9 (+0.724); percentage of bands complete 0.775 (+0.025); incom­ plete bands often blotched on venter, always anterior. Ventrals plus caudals 168-196, mean 181.1 (+3.2). Ratio (bw/iw) of midbbdy band and interspace widths 0.276-0.552, mean 0.384 (+0.013).

Remarks

The type locality of £. palarostris was reported as five miles south of Magdalena, Sonora (see Fig. 3). Dr. George Lindsay

(Director, California Academy of Sciences) collected the type specimen.

In regard to the stated type locality. Dr. Lindsay (pers. comm.) states that "the type specimen of Chionactis palarostris was collected in

Sonora, Mexico. However, through no fault of Dr. Klauber, the precise locality given in the original description may be in error. I suspect that the specimen was taken a few miles south of Hermosillo, rather than near Magdalena, and that the wrong locality information was given to

5 6

Dr. Klauber. I think the snake locality data was confused with some plant collections made a few miles south of Magdalena, Sonora."

Chionactis jk palarostris has been recorded only between Hermo- sillo and Guaymas; no specimens of iC. palarostris have been recorded between Magdalena and Hermosillo (see Fig. 3), although Chionactis occipitalis are recorded 40 miles northwest of , Sonora. Since the type locality of C. jk palarostris seems to be in error, it is here redesignated as six miles south of Hermosillo, Sonora, Mexico. CHIONACTIS PALAROSTRIS ORGANICA KLAUBER

Chionactis palarostris organica Klauber, 1951:141

Diagnosis

Scales between paired parietals and first band 4-6, mean 4.9

(+0.119); bands (body plus tail including black tip" if present) 17-24, mean 19.8 (+0.743); percentage of bands complete, 0.84 (+0.019). In­ complete bands often blotched on venter, always anterior. Ventrals plus caudals 184-199, mean 191.6 (+1.709). Ratio (bw/iw) of mid-body band and interspace widths 0.60-0.925, mean 0.763 (+0.039).

Remarks

Chionactis £. organica is known only from Organ Pipe Cactus

National Monument, Pima County, Arizona. All the specimens examined were recorded on Arizona State Highway 85 between Lukeville and the northern boundary of the monument with the exception of one specimen recorded one mile southeast of Sonoyta, Sonora (see Fig. 3).

Chionactis £. organica and (3. £. palarostris are similar in configuration and coloration, although the interspace color of £. jk palarostris is scarlet whereas C. g_. organica is Brazil red (Ridgway,

1912). These color determinations are consistent with Klauber (1951).

The two populations differ consistently in: (1) the number of scales between the parietals and first band (see Fig. 1), organica

7 8

4-6, palarostris more than 8; (2) the number of bands, organica 17-24

(mean 19.8), palarostris 11-18 (mean 13.9); (3) the number of ventrals plus caudals (see Fig. 1), organica 184-199 (mean 191.6), palarostris

168-196 (mean 181.1); (4) the ratio (bw/iw) of the midbody band and interspace widths (see Table 1), organica 0.60-0.925 (mean 0.763), palarostris 0.276-0.552 (mean .0.384).

The geographic distribution of the two populations appears to be disjunct. Chionactis ,p. organica, with one exception, has been recorded only from Organ Pipe Cactus National Monument, Arizona, where­ as specimens of j]. £. palarostris are known from several localities be­ tween Hermosillo and Guaymas, Sonora, 230 air miles south of Organ Pipe

(see Fig. 3). Although the stated type locality of £. £. palarostris is within this 230 mile interval, I believe the locality is in error. CHIONACTIS PALAROSTRIS SERI, SUBSP. NOV.

Holotype

LACM 40598, subadult female from 18.2.miles south of El Desem- boque del Rio San Ignacio, Sonora, Mexico, collected February 18, 1968, by Richard S. Felger.

Paratypes

Thirteen (all from Sonora, Mexico): ASDM 1517, mainland oppo­

site Tiburon Island; ASDM 1726, Kino Bay; LACM 40599, 4 miles east Kino

Bay; LACM 40600, 8 miles north Hermosillo; MCZ 36890, Costa Rica Ranch;

MVZ 76496, 20 miles north Hermosillo; SDSNH 45222, 10 miles east of Kino

Bay; SDSNH 45223, 15 miles east of Kino Bay; UAZ 20969, 2 miles north­

east Desemboque (Rancho Miramar); UAZ 28054, 40.5 miles north Kino Bay;

UAZ 29283, El Desemboque del Rio San Ignacio; UAZ 30923, 40.5 miles

north Kino Bay; UIMNH 79484, 14.5-16.5 miles west Hermosillo.

Diagnosis

A subspecies of Chionactis palarostris distinguished by having

4-6 scales between paired parietals and first band; number of bands

(body and tail including black tip if present) 17-24; ratio of complete

bands to total bands, 0.70; ventrals plus caudals 168-193; ratio (bw/iw)

midbody band and interspace widths 0.37-0/73.

9 10

Chionactis p. seri differs from C^. palarostris in; (1) num­ ber of scales between parietals and first band (see Fig. 1), seri 4-6, palarostris more than 8; (2) number of bands, seri 17-24 (mean 20.4), palarostris 11-18 (mean 13.9); ratio (bw/iw) of midbody band and inter­ space widths (see Table 1), seri 0.37-0.73 (mean 0.56, palarostris

0.276-0.552 (mean 0.384). Ventral caudal counts similar (see Fig. 1); seri 168-193 (mean 180.5), palarostris 168-196 (mean 181.1).

Chionactis £. seri differs from C^. ]3. organica in: (1) ventral-caudal counts (see Fig. 1), seri 168-193 (mean 180.5), organica

184-199 (mean 191.6); (2) ratio (bw/iw) of midbody band and interspace widths (see Table 1); seri 0.37-0.73 (mean 0.56), organica 0.60-0.925

(mean 0.763); (3) percentage of complete bands, seri 0.70 (+0.046), organica 0.84 (+0.019). Chionactis p. seri is similar to C^. £.• organica in: (1) number of scales between parietals and first band (see Fig. 1), seri 4-6 (mean 5.6), organica 4-6 (mean 4.9); (2) number of bands, seri

17-24 (mean 20.4), organica 17-24 (mean 19.8).

Description of Holotype

Subadult female, snout-vent length 139 mm, tail length 29 mm

(measured five days after preservation); ventrals 142, caudals 45; scale rows 15 at midbody.

Color of interspace saddle Begonia Rose (Ridgway, 1912); inter­ space saddle at midbody involving 11 scale rows and not entering first or second scale rows on either side; posterior saddles of tail touching

subcaudals; 14 black body bands, three incomplete; four black tail bands

(no tail tip). OPCNM C.p.organica 191.2 dh 0.75 - N= 2 3

1 it N ALTAR C.p. orqanicaxseri 183.5 ± 1.53 z .

KINO C.g. seri 1 8 0 .5 ± 1 .8 2 INM z 1 A

HERMOSILLO- C.p. palarostris 181.1 ± 1.41 IN w c O GUAYMAS 1 1 1 1 1 1 1 i 165 170 175 180 185 190 195 2 0 0

OPCNM C.p.organica 4.9 1 ±0.1 jL N = 2 3

ALTAR C.p. organica x seri 4 .8 3 db 0.17 JL N = 7 Tt z KINO C.p. seri 5 . 6 ± 0 . 2 2 II

HERMOSILLO-■ C.p.palarostris 11- 9 ± 0 . 2 6 A N 9 20 GUAYMAS 1 i i i 1 1 0 5 10 15 20 25

Figure 1. Variation in the number of ventrals plus caudals for four populations of Chionactis palarostris (above), and in the number of scales between the parietals and first body band (below). Vertical lines represent the sample mean, horizontal lines, the range of variation and solid bar, the mean + t.95 times the standard error of the mean. %*«*»•>

Figure 2. Chionactis p. seri, female, SDSNH 45222, 10 miles east of Kino Bay, Sonora, Mexico. Photo by Ron Garrison, San Diego Zoo Lab. 13

Altar

Hermosillo

A = C. p. organica Guaymas ★ = C.p. organica x ser; 0 = C.p. seri © - C.p. palarostris

SCAUE 25 50 75 100 miles

Figure 3. Map of Sonora, Mexico and southern Arizona showing the distri­ bution of the four populations of Chionactis palarostris. TABLE 1

Data for comparison of four populations of Chionactis palarostris. See text and Fig. 1

Scales Total Bands• Ventrals + Band Width/ Parietal- Number Complete (%) Caudals Interspace 1st Band Black Bands Width

£. j k organica 4.9 +_ 0.12 19.8 ^ 0.74 0.84 +_ 0.019 191.6 +_ 1.71 0.76 +_ 0.039

£. organica x seri 4.8 +_ 0.17 19.3 +_ 0.65 0.79 +_ 0.068 183.5 ^ 1.53 0.61 +_ 0.025

£. £. seri 5.6 + 0.22 20.4 + 0.65 0.70 + 0.046 180.5 + 1.82 0.56 + 0.032

£. £. palarostris 11.9 + 1.45 13.9 + 0.72 0.76 + 0.025 181.1 + 3.20 0.38 + 0.013' 15

TABLE 2

Data for the thirteen paratypes of Chionactis £. seri. Column numbers represent (1) number of scales between parietals and first band, (2) total number of bands, (3) number of complete bands, (4) number of ventral caudal scales, and (5) ratio midbody and inter­ space widths.

Paratypes 1 2 3 4 5

SDSNH 45222 6 19 11 179 74:130 mm

SDSNH 45223 5 19 13 187 76:109 mm

UAZ 20969 6 23 . 16 193 30:50 mm

UAZ 28054 4 21 21 187 17:27 mm

UAZ 29283 4 21 12 179 55:75 mm

UAZ 30923 5 24 17 180 42:113 mm

ASDM 1517 4 23+ 21 174 40:70 mm

ASDM 1726 4 25 22 181 58:86 mm

MCZ 36890 5 19 15 174 23:51 mm

MVZ 76496 6 21 7 173 50:129 mm

LACM 40599 5 20 18 185 50:89 mm

LACM 40600 6 17 10 181 51:121 mm

UIMNH 79484 6 17 7 168 17:39 mm 16

Head with black crescent involving all or portions of following scales: posterior one-half of frontal and supraoculars, all but pos­ terior edge of parietals, all of paired postoculars, portions of third, fourth and fifth supralabials, portions of temporals and one-half of preoculars.

Head scalation resembling other populations of Chionactis having paired postoculars; single preocular and loreal; seven supra­ labials and infralabials. Midbody band width 35 nun; adjacent inter­ space width 60 mm.

Variation

Number of scales between parietals and first body band 4-6, mean 5.64 (^.22); number of bands (body plus tail including tip if pre­ sent) 17-24, mean 20.4 (+0.65); mean of percentage of bands complete

0.70 (+0.046); ventrals plus caudals 168-193, mean 180.5 (+1.82); mid­ body band and interspace widths ratio 0.37-0.73, mean 0.56 QH).03) (see

Table 2). Convex snout in all specimens examined (snout of Costa Rica

Ranch specimen MCZ 36890, not determined).

Habitat

The type locality is approximately sea level near the beach.

The hills, a short distance to the cast, are 30-60 meters in elevation

with a north-northwesterly trending peak of 713 meters and a

south-southwesterly trending peak of 561 meters. A complex mosiac of

sand and desert pavement covers most of the Desemboque area. Felger

(1965) has discussed the habitat and cited some of the common perennial

plants of the region. 17

Problems

Recent collecting has uncovered, in the vicinity of Altar,

Sonora (see Fig. 3), specimens of palarostris which seem to be intermediate between jd. organica and C^. ■£_. seri (see Table 1 and

Fig. 1). Only seven specimens have been collected and at this time it is impossible to allocate them to either population. It is conceivable that in the future, additional specimens of palarostris will be found along the foothills and bajadas from Arizona to Kino Bay where the moisture is sufficient to support the vegetation with which (% palarostris seems to be associated.

The close relationship between (X £. organica and C_. jk seri has been demonstrated. The almost sympatric association between C. ]3.- palarostris and C^. ]3. seri with no apparent intergradation of characters is difficult to explain. In the vicinity of Hermosillo, collecting re­ cords show that individuals from these two *'subspecies11 occur within a few miles of each other, but the character analysis gives no indication of intergradation. Unfortunately, recent agricultural developments in this area have destroyed much of the habitat and may render this problem unsolvable. SPECIMENS EXAMINED

Chionactis palarostris palarostris, 23

Mexico, Sonora: ASDM 1346, 43 miles south of Hermosillo;

ASDM 1407, 35 miles south Hermosillo; ASDM 1725, 72 miles north Guaymas;

CSCLB 1162, 4 miles north Guaymas; CSCLB 1163, 3.5 miles north Guaymas;

CSCLB 1164 , 6 miles north Guaymas; CSCLB 1165, 5 miles north Guaymas;

CSCLB 1166, 15 miles north Guaymas; CSCLB 1167, 3 miles north Guaymas;

CSCLB 2252, 7.3 miles north Guaymas; CSCLB 3014, 33 miles south Hermo­

sillo; CSCLB 3015, 30 miles south Hermosillo; CSCLB 3016, 31 miles south

Hermosillo; LACM 9122, 6 miles south Hermosillo; LACM 9123, 43 miles

south Hermosillo; LACM 9124, 6 miles south Hermosillo; LACM 9125, 13 miles south Hermosillo; MVZ 50809, 40.7 miles south Hermosillo; SDSNH

26771, 5 miles south Magdalena; UAZ 20970, 34 miles south Hermosillo;

UAZ 20971, 20 miles south La Peintada; UAZ 20972, 6 miles south Hermo­

sillo; UAZ 20973, 11.7 miles south Hermosillo.

Chionactis palarostris organica, 24

Arizona, Pima County: ASDM 1216, 36 miles south Ajo; ASDM 1762,

1.5 miles north Organ Pipe Headquarters; ASDM 1793, Organ Pipe Cactus

National Monument; CSCLB 1168, 36 miles south Ajo on Hwy. 85; CSCLB 1169,

29 miles south Ajo on Hwy. 85; CSCLB 1170, 16 miles south Ajo on Hwy. 85;

JFC 42-43, 6.1 miles north Lukeville; JFC 62-44, 9.3 miles south Hwy. 86

on Ariz. 85; LACM 34915, 13.8 miles south Organ Pipe Cactus National

18 19

Monument northern boundary; MCZ 62381,.Gila Bend Road, Sonoyta; SDSNH

43341, 15 miles south Gunsight Jet.; SDSNH 43342, 5 miles south Gun- sight Jot.; UAZ 20967, 5 miles north OPCNM Headquarters; UAZ 20968,

23.8 miles south on Hwy. 85 from Jet. Ajo Road; UIMNH 5602, 29.8 miles south Ajo; UIMNH 5603, 20.5 miles south Ajo; UIMNH 5604, 33.7 miles south Ajo; UIMNH 5605, 8 miles north Sonoyta; UIMNH 5606, 22 miles south

Ajo; UIMNH 5906, Organ Pipe Cactus National Monument; UIMNH 10629, 38.5 miles south Ajo; UIMNH 10630, 38 miles south Ajo; UIMNH 79485, 9 miles north Sonoyta.

Mexico, Sonora: LACM 25897, 1 mile southeast Sonoyta.

Chionactis palarostris seri, 14

Mexico, Sonora: ASDM 1517, mainland opposite Tiburon Island;

ASDM 1726, Kino Bay; LACM 40598, 18.2 miles south El Desemboque del Rio

San Ignacio; LACM 40599, 4 miles east Kino Bay; LACM 40600, 8 miles north Hermosillo; MCZ 36890, Costa Rica Ranch; MVZ 76496, 20 miles north

Hermosillo; SDSNH 45222, 10 miles east of Kino Bay; SDSNH 45223, 15 miles

east of Kino Bay; UAZ 20969, 2 miles northeast Desemboque (Rancho Mira­ mar) ; UAZ 28054, 40.5 miles north Kino Bay; UAZ 29283, El Desemboque

del Rio San Ignacio; UAZ 30923, 40.5 miles north Kino Bay; UIMNH 79484,

14.5-16.5 miles west Hermosillo.

Chionactis p. organica x seri, 7

Mexico, Sonora: LACM 50782, 19.7 miles southeast Altar; UAZ

30732, 22 miles southeast Altar; UAZ 30735, 24 miles southeast Altar;

UAZ 30736, 14 miles southeast Altar; UAZ 30740, 17 miles southeast Al­

tar; UAZ 30742, 20 miles southeast Altar; UAZ 31276, 18 miles SE Altar. LITERATURE CITED

Felger, Richard S. 1965 Xantusia vigilis and its habitat in Sonora, Mexico. Herpteologica, 21:146-147.

Funk, Richard S. 1967 A new colubrid snake of the genus Chionactis from Arizona. Southwest Nat. 12 (z):180-188.

Hensley, M. Max. 1950 Results of a herpetological reconnaissance in extreme southwestern Arizona and adjacent Sonora, with a des­ cription of a new subspecies of the Sonoran whipsnake, Masticophis bilineatus. Trans Kansas Acad. Sci., 53:270-288.

Klauber, L. M. 1937 A new snake of the genus Sonora from Mexico. Trans. San Diego Soc. Nat. Hist., 8:363-366.

______. 1951 The shovel-nosed snake, Chionactis with descrip­ tions of two new subspecies. Trans. San Diego Soc. Nat. Hist., 11:141-204.

Ridgway, Robert. 1912 Color standards and color nomenclature, Washing­ ton, pp. iii +43, 53 plates.

Stickel, William H. 1941 The subspecies of the spade-nosed snake, Sonora occipitalis. Bull. Chicago Acad. Sci., 6:135-140.

1943 The Mexican snakes of the genera Sonora and Chionactis with notes on the status of other colubrid genera. Proc. Biol. Soc. Wash., 56:109-128.

20 6 0 4 7 9