Volume 4 — THE SPECIES OF THE REPTILIAN GENUS ANNIELLA, WITH ESPECIAL REFERENCE TO ANNIELLA TEXANA AND TO VARIATION IN ANNIELLA NIGRA

BY JOHN VAN DENBURGH

Curator of the Department of Herpetology.

The genus Anniella was established by J. E. Gray[10], in 1852, to contain a single species which he named Anniella pulchra and described in the following terms:

"Silvery (in spirits); upper part with very narrow brown zigzag lines placed on the margin of the series of scales, the line down the center of the back and two or three on the upper part of the sides being thicker and nearly half the width of the scales.

Hab. California, J. O. Goodridge, Esq., Surgeon R. N."

This species has since been more completely described by Bocourt,[11] Boulenger,[12] Cope,[13] and Van Denburgh.[14]

In 1885 Fischer[15] described under the name Anniella nigra a specimen said to have been collected at San Diego, California. This, he stated, differed from Anniella pulchra in the following characters:

Twenty-eight longitudinal rows of scales.

The three median preanal scales twice as long as those preceding.

Tail one-third total length.

Color above black.

I have elsewhere[16] stated that the number of scale rows in Anniella pulchra varies from twenty-four to thirty-four. The preanal scales in both the dark and light forms may be small, moderately enlarged, or twice the length of those preceding. The tail of A. pulchra may equal or exceed one-third of the total length of the animal. I have been unable to discover any differences in the squamation of dark and light specimens; and since the recognition of A. nigra as distinct from A. pulchra must rest solely upon the difference in pigmentation, one is tempted to inquire whether this is not merely an instance of melanism. Upon this subject I shall have more to say, but I wish first to consider certain peculiarities of squamation which have been held to distinguish another species.

Anniella texana was described by Mr. Boulenger,[17] in 1887, from a single specimen labeled El Paso, Texas—a locality so far beyond the limits of the known range of the genus and of other Californian reptiles that it must be regarded with much suspicion until confirmed by the capture of additional specimens. The type of A. texana agrees in coloration with Anniella pulchra, but Mr. Boulenger finds it to differ in certain details of squamation. He assigns to it the following characters:

Head less depressed, snout more rounded than in A. pulchra.

A horizontal suture from nostril to second labial.

Frontal twice as broad as long.

Anterior supraocular nearly as broad as its distance from its fellow.

Interparietal and occipital divided (anomalously?) by a longitudinal suture.

Six upper labials, etc.

A narrow shield separates the third labial from the loreal.

Five lower labials.

Twenty-eight scales around middle of body.

No enlarged preanal scales.

Tail ending obtusely, three-eighths total length.

Dark gray above, with three fine black longitudinal lines; sides and lower surfaces whitish.

I will now consider these characters in connection with variations found in a series of specimens of A. pulchra and A. nigra.

1. The shape of the head and snout is subject to some variation in both A. pulchra and A. nigra. Unless the difference in shape in the type of A. texana is very great, one is safe in ignoring it as a basis of specific distinction.

2. One of my specimens of A. nigra (Cal. Acad. Sci. No. 6255) shows a horizontal suture extending from the nostril to the second labial. Another (No. 6244) has such a suture between the nostril and the rostral plate.

3. There is considerable variation in the shape and size of the frontal plate in both A. pulchra and A. nigra. It not infrequently is twice as broad as long (No. 6236, etc.), but may be nearly as long as broad. Sometimes it nearly touches the rostral (No. 5103).

4. The anterior supraocular is nearly as broad as the distance which separates it from its fellow in some specimens of A. pulchra (No. 5110) and A. nigra (Nos. 6233, 6243, 6249, etc.). In some specimens it has scarcely more than half this breadth.

5. I regard the plates which Mr. Boulenger calls interparietal and occipital as frontoparietal and interparietal, respectively. The former plate is not completely divided in any of my specimens. One example of A. pulchra (No. 5110), however, has it longitudinally divided throughout the posterior third of its length. The interparietal (occipital of Mr. Boulenger) is completely divided longitudinally in one example of A. nigra (No. 6228) and divided through one-fifth its length in another (No. 6218).

6. This is the normal arrangement, but is subject to variation.

7. This shield may be absent.

8. The number of lower labials ranges from five to seven.

9. The number of scales around the middle of the body varies in A. pulchra from twenty-four to thirty-four, while in 54 specimens of A. nigra the number is twenty-eight in 12, thirty in 36, and thirty-two in 6.

10. The preanal scales, as already stated, may be not enlarged, moderately enlarged, or twice as long as those preceding them. This is true in both A. pulchra and A. nigra.

11. The length of the tail is subject to so much variation that it cannot be regarded as furnishing a good specific character. The longest ones I have seen are one-third the total length in A. nigra and two-fifths in A. pulchra.

12. This is the coloration of some specimens of A. pulchra.

It will be seen that, with one exception, all of the characters of Anniella texana have been found in specimens of A. pulchra and A. nigra either as the normal condition or as individual variations. The single exception is the complete division of the frontoparietal plate—a condition which is manifestly anomalous, since this plate has been found partially divided in other specimens. It is evident therefore that Anniella texana must stand as a synonym of A. pulchra Gray.

Anniella texana being thus disposed of, one is tempted to treat A. nigra in the same way, regarding it as based merely upon melanistic individuals of A. pulchra. This view we certainly should have to adopt if both dark and light colored specimens occurred in the same localities, but I believe this has not yet been shown to be the case. Fischer, to be sure, states that the type of A. nigra came from San Diego, where A. pulchra is especially abundant, but it is quite possible that his specimen did not really originate there. All of the dark specimens I have seen, have been secured on the coast of Monterey County; and, aside from Fischer's, I know of no records of the black Anniella from any other locality, except Cope's[18] reference to specimens from San Francisco. Aside from the type locality, then, it would seem that the dark form has a very limited range, being confined to the southern part of the Pacific Fauna of the Transition Zone.

In a large series of alcoholic specimens from the coast of Monterey County, I find very few showing a style of coloration similar to that of A. pulchra. A specimen from San Ardo, in the interior of this county, is typical of A. pulchra, but San Ardo is in the Upper Austral Zone. Not more than four or five of the fifty-four specimens from the coast zone could be in the least confusing, and all of these are more deeply pigmented above than is any example of A. pulchra before me. Forty-eight of these specimens were sent me alive, and in that condition exhibited a greater range of coloration than they show since preservation in alcohol, which seems to have intensified their dark pigmentation while dissolving the beautiful yellow of their lower surfaces. When the living lizards were received from Carmel and Point Pinos, they were divided into ten groups according to the intensity of the dorsal pigmentation, and measurements were taken of each specimen in each group. These grades of pigmentation of the living specimens, with measurements in millimeters from snout to anus and anus to tip of tail, are as follows:

1. Entire upper surface (ten, twelve, or fourteen rows of scales) and ventral surface of tip of tail very dark Indian purple. Chin and throat lighter Indian purple. More or less suffusion with Indian purple about anus. Rest of lower surfaces and sides bright gamboge yellow with chromium green staining near center of belly. Mouth flesh-color. Labials and temporals minutely dotted with iridescent greenish, silvery, or bronze. Eye black with bronze or silvery markings.

153 15 Lateral line present No dorsal line

150 73 Lateral line Trace dorsal line

150 70 Lateral line Trace dorsal line

150 38 Lateral line No dorsal line

147 40 No lateral line No dorsal line

146 75 No lateral line No dorsal line

146 25 Lateral line No dorsal line

145 70 Trace lateral line No dorsal line

143 17 Trace lateral line No dorsal line

140 68 Lateral line No dorsal line

140 50 Lateral line No dorsal line

138 32 Faint trace lateral lines No dorsal line

137 68 Lateral line Trace dorsal line

137 47 Lateral line Trace dorsal line

136 45 Lateral line No dorsal line

135 65 Lateral line No dorsal line

135 53 Trace lateral line No dorsal line

134 65 Lateral line No dorsal line

133 60 Lateral line No dorsal line

132 63 Lateral line Trace dorsal line

131 50 Lateral line No dorsal line

131 16 Lateral line No dorsal line

130 34 Lateral line No dorsal line

2. Dark hair-brown above; bright gamboge below; chin Indian purple.

146 70 Lateral line No dorsal line

131 20 Two lateral lines Trace dorsal line

3. Dark purplish drab above; wax-yellow with Paris or chromium green below; chin and throat lighter Indian purple.

140 40 Two lateral lines Trace dorsal line

134 20 Lateral line Faint trace dorsal line

123 25 Lateral line No dorsal line

120 60 Lateral line Fair dorsal line

4. Hair-brown above; gamboge below; chin Indian purple.

130 65 Two lateral lines Dorsal line

120 52 Lateral line Faint dorsal line

5. Dark drab above; waxy gamboge below.

126 65 Two lateral lines Distinct dorsal line

126 60 Lateral line Indistinct dorsal line

125 20 Two lateral lines Faint dorsal line

125 60 Two lateral lines Indistinct dorsal line

6a. Bronzed drab above; light wax-color below; chin light Indian purple.

125 63 Two lateral lines Faint dorsal line

6b. Drab above; light wax-color below; chin light Indian purple.

117 55 Two lateral lines Faint dorsal line

116 55 Two lateral lines Faint trace dorsal line

112 20 Two lateral lines Dorsal line

105 48 Two lateral lines Dorsal line

7. Grayish drab above; wax-yellow below; chin lighter Indian purple.

126 30 Two lateral lines Faint trace dorsal line

122 60 Two lateral lines Trace dorsal line

121 20 Two lateral lines Incomplete dorsal line

119 55 Strong lateral line Trace dorsal line

116 55 Strong lateral line Faint trace dorsal line

8. Dark drab-gray above; dull wax-yellow below; chin light Indian purple.

124 60 Lateral line Faint dorsal line

9. Drab-gray above; straw and Naples yellow below; chin light Indian purple.

118 56 Two lateral lines Dorsal line

10. Bronzed drab-gray above; pale wax-yellow below; chin light Indian purple.

92 41 Two lateral lines Very distinct dorsal line

These notes show clearly that the intensity of pigmentation increases quite gradually and fairly regularly with the size of the individual, and that while young specimens may be nearly as pale as some dark individuals of A. pulchra, all of the large specimens are of the dark type. It is also true in a general way that the smaller the specimen the more distinctly the lines are shown.

In the light of our present knowledge, therefore, it seems necessary to regard Anniella nigra as a local and probably recently differentiated race rather than as a melanistic phase of Anniella pulchra. While the difference is purely one of color, no intergradation has yet been shown to occur in adult specimens, and the two forms must therefore be recognized as distinct species occupying separate areas in different faunal zones.

If then we ignore the localities of the type specimens of "A. texana" and A. nigra, as open to question until confirmed by the finding of additional specimens, the known distribution of the species of the genus Anniella is as follows:

Anniella pulchra.

Upper Austral Zone.

San Diegan Fauna.

San Diego County.

San Diego, Coronado, mountains near San Diego.

Riverside County.

San Jacinto.

San Bernardino County.

San Bernardino.

Californian Fauna.

Kern County.

Oil City to Poso Creek.

Tulare County.

Sequoia National Park.

Fresno County.

Fresno.

Monterey County (interior).

San Ardo.

San Benito County.

Bear Valley.

Contra Costa County.

Anniella nigra.

Transition Zone.

Pacific Fauna.

Monterey County (coast).

Monterey, Pacific Grove, Point Pinos, Carmel Bay.

San Francisco County.

San Francisco.

San Francisco, California,

August 18, 1905.

PROCEEDINGS

OF THE

CALIFORNIA ACADEMY OF SCIENCES

Third Series

Zoology Vol. IV, No. 3

Issued December 2, 1905