Part 6

Diagnosis.--Lateral dark stripe anteriorly passing through eye and posteriorly involving fourth scale-row only; first scale-row darkly pigmented; no paravertebral stripe; no dark pigment on vertebral row; six or eight dark stripes at mid-body, secondary stripes often present posteriorly; usually eight (sometimes seven) supralabials immaculate or having dark ventral margins.

Variation.--Twenty-six specimens have 157 to 169 (163.5 +- 3.59) ventrals. Twenty of these snakes having complete tails have 60 to 73 (66.5 +- 4.26) subcaudals; the number of ventrals plus subcaudals varies from 224 to 238 (230.1) in nineteen of these. In 26 specimens the reduction from 19 to 17 dorsal scale-rows takes place between ventrals 91 and 107 (100.2 +- 3.59). Sexual dimorphism is evident in the number of subcaudals; nine females have 60 to 66 (62.4), and 11 males have 68 to 73 (69.8) subcaudals. The largest specimen (AMNH 19643) is a male from "Mexico," having a body length of 626 mm., a tail length of 168 mm. and a total length of 786 mm. No small juveniles have been examined; the smallest specimen (AMNH 19618) is a male from Veracruz, Mexico, having a body length of 325 mm., a tail length of 90 mm. and a total length of 415 mm.

The greatest variation is in coloration. In preserved specimens the ground-color is white, tannish-white, or often pale blue, with dark stripes of black or deep brown present dorsolaterally and laterally. Secondary stripes of paler brown are sometimes present, but the pale browns have faded badly on many specimens. Normally four black stripes are present at mid-body--a lateral pair on the 4th row of dorsal scales and a dorsolateral pair on the 7th row (fig. 1, D). The lateral pair is the posterior continuation of the stripe that on the head passes through the eye; it continues on the nape as a narrow stripe on the 4th row only. In a few specimens the lateral stripe broadens to include the upper third of the 3rd row posterior to the nape. In some specimens both the dorsolateral and lateral dark stripes are present on the nape as a row of elongated spots or dashes that become continuous stripes of even width one-third to one-half of the distance posteriorly along the body; in other specimens the stripes are continuous on the nape. Posterior to the place of dorsal scale-reduction from 19 to 17 rows by the fusion of the 3rd and 4th rows, the lateral and dorsolateral stripes are moved downward by one row. In some specimens secondary black or dark brown stripes are present in the form of a series of dashes on the 5th and 8th rows; posterior to the place of scale reduction, these dashes are on the 4th and 7th rows. These dashes form a continuous stripe near the base of the tail. On the tail the secondary and primary stripes on adjacent rows sometimes fuse into a single broader stripe.

Usually the 1st row of dorsal scales is dark brown; in some specimens the brown on the 1st or 7th row has faded in preservative. A few specimens have small black spots on the moderate brown background of the 1st row; in others the 1st row is only a somewhat darker brown than the ground-color. The 2nd row sometimes is a medium brown, and appears to be an additional stripe.

The ventrals usually have more or less conspicuous dark spots laterally; in some specimens there are no spots. Except for the lateral spots (when present) the ventrals are immaculate white. The dorsal ground-color is pale brownish-white, white or pale blue between the 4th and 7th rows of dorsal scales and dorsally between the 7th rows on each side. Stripes are never present on the uniformly pale colored 8th, 9th and vertebral scale-rows.

Usually there are eight supralabials on each side; however, seven of the 27 specimens examined have seven supralabials on each side, and three others have seven on one side, and eight on the other. Never is more than the lower third of the supralabials dark brown. In many specimens little or no brown is on the supralabials. There is little or no brown on the chin.

Variation in coloration and in number of supralabials appears to be of no geographic significance.

Although no juveniles have been collected, I expect that juveniles resemble adults in coloration. Probably there would be a greater contrast between the dark stripes and the pale ground-color in juveniles.

In life an adult from three miles northwest of Lerdo de Tejada, Veracruz, Mexico (UMMZ 114484), had black stripes on the 4th and 7th rows of dorsal scales, and black spots on a brown background on the 1st row. The 2nd row had a medial, pale to medium brown auxiliary stripe on a brownish-white background. Posterior to the nape the 3rd row was medium brown. The area between the 4th and 7th rows and the dorsum between the 7th row of scales on each side was a pale brownish-white. Posterior to the place of scale-reduction the primary stripes were displaced downward by one row to the 3rd and 6th rows and secondary stripes originated as elongated spots on the 4th and 7th rows. Near the tail the secondary stripes were broad and continuous. The head was white or tannish-white with three dark brown or black stripes.

Remarks.--In his diagnosis of C. l. lineatus, Smith (1941:122) states: "lateral dark stripe ... very narrow posterior to nape, extending along fourth scale row; posteriorly a stripe along third and eighth (farther posteriorly the seventh) scale rows; a narrow dark stripe along sixth scale row, continuous throughout length of body...." I fail to find a dark stripe on the 6th row throughout the length of the body. In all specimens that I have seen, there is a dark stripe on the 7th row anteriorly and on the 6th row posteriorly. In many specimens the stripes on the 3rd and 8th (posteriorly the 7th) scale-rows are absent or present so far posteriorly that the 8th row is never involved.

The dark brown on the first scale-row and the presence of a lateral dark stripe on the 4th row of dorsal scales only, in combination with the characteristics of the genus, distinguish C. l. lineatus from all other snakes in Mexico.

Distribution.--Semi-arid habitats on the coastal plain of Veracruz, Mexico, from Tecolutla to Lerdo de Tejada and Piedras Negras (fig. 2).

Specimens examined.--Total of 27, as follows: MEXICO: no specific locality, AMNH 19614-15, 19621-24, 19642-43, NMW 16827. Veracruz: no specific locality, AMNH 19618-20, CAS 73640, NMW 16829; 4 km. S Alvarado, KU 58124; 14 mi. N Alvarado, UIMNH 46978; 6 mi. SE Boca del Rio, UIMNH 28023; Etiopa, 2 mi. S Tecolutla, UIMNH 3847; ca. 30 mi. E Jalapa, AMNH 81948; 3 mi. NW Lerdo de Tejada, UMMZ 114484-85; Paso del Macho, USNM 109708; Rio Blanco, 20 km. WNW Piedras Negras, KU 23253; Veracruz, AMNH 19612, UF 8990; W side Veracruz, AMNH 19616; 2 mi. W Veracruz, AMNH 19617, 19619.

=Conophis lineatus concolor= Cope

Conophis vittatus Cope, Proc. Acad. Nat. Sci. Philadelphia, 13:300, December 28, 1861 (nec Peters, 1860; type.--United States National Museum, no. 4941; type locality--"Peten," Guatemala); Journ. Acad. Nat. Sci. Philadelphia, ser. 2, 8:137, 1876; Bull. U. S. Natl. Mus., 32:76, 1887.

Conophis concolor Cope, Proc. Acad. Nat. Sci. Philadelphia, 18:318-319, February 20, 1867; Journ. Acad. Nat. Sci. Philadelphia, ser. 2, 8:137, 1876; Bocourt in Dumeril, Bocourt and Mocquard, Mission Scientifique au Mexique et dans l'Amerique Centrale, 2:648, 1886; Mueller, Verh. Ges. Basel, 8:263, 1887; Cope, Bull. U. S. Natl. Mus., 32:77; 1887; Ann. Rept. U. S. Natl. Mus. for 1898, p. 1095, 1900; Schmidt and Andrews, Zool. Ser. Field Mus. Nat. Hist., 20:178, October 31, 1936; Andrews, Zool. Ser. Field Mus. Nat. Hist., 20:358, December 28, 1937; Smith, Occas. Papers Mus. Zool. Univ. Michigan, 388:7, October 31, 1938; Taylor and Smith, Univ. Kansas Sci. Bull., 25:253, July 10, 1939; Smith, Zool. Ser. Field Mus. Nat. Hist., 24:31, January 30, 1939; Cochran, Bull. U. S. Nat. Mus., 220:167, 1961; Neill and Allen, Herpetologica, 17:44-46, fig. 3, April 15, 1961.

Conophis lineatus (in part), Guenther, Biologica Centrali-Americana, p. 165, March, 1895; Gaige in Pearse, et al. Carnegie Inst. Washington Publ., 457:302, February 5, 1936.

Conophis lineaticeps Cope, Ann. Rept. U. S. Natl. Mus. for 1898, pp. 1094-95, 1900 (Substitute name for Conophis vittatus Cope, 1861, nec Peters, 1860).

Conophis lineatus concolor, Smith, Journ. Washington Acad. Sci., 31:122-123, March 15, 1941; Proc. U. S. Natl. Mus., 92:395, November 5, 1942; Proc. U. S. Natl. Mus., 93:407, October 29, 1943; Smith and Taylor, Bull. U. S. Natl. Mus., 187:43, October 5, 1945; Univ. Kansas Sci. Bull., 33(pt. 2):352, March 20, 1950.

Types.--Two in the United States National Museum, no. 12368 (two specimens). Type locality: "Yucatan," restricted to Chichen Itza, Yucatan, Mexico by Smith and Taylor (1950:352).

Diagnosis.--Dark stripes either absent posterior to the nape, or present as a row of small spots on fourth or seventh scale-row; no dark stripe on first scale-row; eight supralabials having dark ventral margins.

Variation.--Forty-five specimens have 158 to 170 (163.7 +- 1.56) ventrals. Thirty-eight of these snakes having complete tails have 56 to 74 (66.7 +- 4.77) subcaudals; the number of ventrals plus subcaudals varies from 222 to 245 (230.6). In 45 specimens the reduction from 19 to 17 dorsal scales takes place between ventrals 89 and 114 (102.5 +- 5.57). Sexual dimorphism is evident in the number of subcaudals; 16 females have 56 to 65 (61.8), and 22 males have 68 to 74 (70.3) subcaudals. The longest specimen (USNM 46395) is a male from Chichen Itza, Yucatan, having a body length of 893 mm., a tail length of 274 mm., and a total length of 1167 mm. A juvenile (AMNH 38833) from Chichen Itza, Yucatan, has a body length of 194 mm., a tail length of 50 mm., and a total length of 244 mm.

The venter is immaculate white or pale yellow and the dorsum of the body is immaculate pale gray to pale olive. Some specimens have small dark brown spots on the tips of the scales of the 4th or of the 7th row, but never on both. Only on the nape are spots present on both the 4th and the 7th rows; these spots are the posterior continuations of the dark stripes on the head and on many specimens do not reach the nape. Posterior to the place of scale reduction from 19 to 17 rows by the fusion of the 3rd and 4th rows of scales, the dark spots (when present) are on the 3rd or 6th row of scales.

The coloration of juveniles is the same as that of adults. Color in life is thought not too different from that of preserved specimens, for notes on the color of living individuals (Neill and Allen, 1961:44) agree with what I have observed on preserved snakes.

Remarks.--The specimen from "Peten" (USNM, no. 4941) is the only specimen that has a controversial history. As can be seen from the synonymy of the species, the relationship of this specimen with the rest of the genus has been interpreted in several ways. Smith (1941:122-123) stated that the above specimen was catalogued as being from El Salvador; however, the locality was presumed by him to be El Peten, Guatemala, due to the presence in the bottle of a piece of paper inscribed "Conophis vittatus, Peten, J. M. Dow." This specimen is the one mentioned by Cope (1861:300, 1876:76, and 1900:1094-95), and in the first paper is ascribed to Guatemala. In 1900 this specimen was named C. lineaticeps by Cope who thought the specimen differed significantly from C. concolor (Cope, 1867:318-319). This specimen has the coloration normal for C. l. concolor as far posteriorly as mid-body; beyond mid-body the dark lines, typical of C. l. lineatus or of C. l. dunni, are present. It is likely that this specimen is an intergrade between C. l. concolor and C. l. dunni, the other subspecies present in Guatemala.

The only specimen not from the Yucatan Peninsula is allegedly from Patuca, Honduras (USNM 20271). It was obtained in the 1870's. Possibly more collecting will verify the presence of C. l. concolor in northern Honduras. This individual may be merely a genetically aberrant specimen from an area where normal specimens are C. l. dunni. Neill and Allen (1961:44-45) suggested that the specimen from Patuca implies widely overlapping distributions for C. l. dunni and C. concolor. The occurrence of C. l. concolor in Honduras needs to be verified before this assumption is made. There can, therefore, at present be no objection to the view that intergradation between the subspecies C. l. dunni and C. l. concolor could occur through a relatively broad area of El Peten and British Honduras.

Neill and Allen (1961:44-45) further suggest that the present range of C. l. dunni extends "presumably still farther northward toward the Mexican state of Veracruz where C. l. lineatus exists." Actually the presence of the subspecies C. l. dunni and C. l. lineatus as presently disjunct populations implies merely that they were presumably a continuous population at some time in the past.

The characteristics of the genus in combination with the reduction of dark coloration posterior to the head distinguish this snake from all other snakes in Mexico and Central America.