A Revision of Snakes of the Genus Conophis Part 2

Costa Rica. D. _C. l. lineatus_ (KU 23253) from Rio Blanco, 20 km. WNW Piedras Negras, Veracruz, Mexico. E. _C. nevermanni_ (ANSP 22424) "San Jose," Costa Rica. F. _C. pulcher_ (UIMNH 33646) from Soconusco, Chiapas, Mexico. G. _C. vittatus_ (KU 39626) from Atencingo, Puebla, Mexico. H. _C. vittatus_ (TCWC 9473) from 1 mi. S Colotlipa, Guerrero, Mexico. I. _C.

vittatus_ (UMMZ 82653) from "vicinity of" Salina Cruz, Oaxaca, Mexico. Approximately 3/4.]

=Conophis lineatus= (Dumeril, Bibron and Dumeril)

_Tomodon lineatum_ (in part) Dumeril, Bibron and Dumeril, erpetologie Generale, 7(pt. 2):936-938, February 25, 1854.

_Diagnosis._--No dark pigmentation posterior to nape; lateral dark stripe anteriorly pa.s.sing through eye and posteriorly involving 4th or 3rd and 4th scale-rows only; first scale-row darkly pigmented; no paravertebral dark stripe; six to thirteen (or no) dark stripes at mid-body; usually eight (sometimes seven) supral.a.b.i.als immaculate white or having dark ventral margins.

_Variation._--The variation in this species is discussed more completely in the descriptions of the subspecies. One hundred and seven specimens have 157 to 178 (164.8) ventrals. Eighty-eight of these snakes having complete tails have 56 to 80 (68.0) subcaudals; the number of ventrals plus subcaudals varies from 222 to 247 (233.5) in 87 of these. On 107 specimens the reduction from 19 to 17 dorsal scale-rows takes place between ventrals 89 and 114 (101.8). s.e.xual dimorphism is evident in the number of subcaudals; there are, on the average, fewer subcaudals in females than in males of each subspecies.

The largest specimen is a male _C. l. concolor_ (USNM 46345) from Chichen Itza, Yucatan, Mexico, having a body length of 893 mm., a tail length of 274 mm. and a total length of 1167 mm. The smallest is a juvenile _C. l. dunni_ (MCZ 49749) from Tegucigalpa, Honduras, having a body length of 162 mm., a tail length of 51 mm. and a total length of 213 mm.

The greatest variation is in coloration. Dark color, or lack thereof, has been used to separate the subspecies of _C. lineatus_. The ground-color is pale brown, pale olive or white, either with no stripes on the body or with eight to thirteen dark stripes at mid-body. Specimens having dark stripes on the body always have black or dark brown pigmentation on the first, 4th and 7th dorsal scale-rows. In some there is dark pigmentation on the 2nd, 3rd, 8th and 10th rows of scales. The stripes appear on the nape or farther posteriorly, usually on the anterior third of the body, either as a series of spots or dashes that form a continuous stripe farther posteriorly or as a continuous stripe.

The ventrals usually have more or less conspicuous dark spots laterally on those specimens having dark stripes present on the dorsum; spots are absent on all specimens having no dorsal stripes and on some specimens having dorsal stripes. Except for the dark lateral spots (when present) the ventrals are immaculate white. Usually the dorsal ground-color is pale tan, especially on the striped forms. The ground-color is usually palest on the lower dorsal scale rows and darkest dorsally.

Three populations are separable as subspecies; one has no stripes on the body and occurs in the Yucatan Peninsula. The other two have stripes on the dorsum and vary clinally in coloration from the north (Veracruz, Mexico) to south (Costa Rica) (Fig. 2). Reasons for separating these widespread, variable snakes into two subspecies are that they are discontinuous in distribution (the population in Veracruz is disjunct from the one that extends from Guatemala to Costa Rica), and that these populations have distinctly different color patterns.

[Ill.u.s.tration: FIG. 2. Selected locality records for the subspecies of _Conophis lineatus_.]

=Conophis lineatus dunni= Smith

_Psammophis lineatus_, Gunther, Catalogue of Colubrine Snakes in the Collection of the British Museum, p. 135, 1858.

_Conophis lineatus_, Cope, 3rd Ann. Rept. Peabody Acad. Sci., p. 82, 1871; Proc. Acad. Nat. Sci. Philadelphia, 23:204, October 24, 1871; Journ. Acad. Nat. Sci. Philadelphia, ser. 2, 8:137, 1876; Bull. U. S. Natl. Mus., 32:77, 1887; Gunther, Biologia Centrali-Americana, p. 165, March, 1895; Boulenger, Catalogue of the Snakes in the British Museum (Natural History), 3:122-123, 1896; Werner, Arch. Naturges., 90, abt. A, 12:143, 1925; Schmidt, Zool. Ser. Field Mus. Nat. Hist., 12:199-200, November 21, 1928; Amaral, Mem. Inst. Butantan, 4:212, 1929; Werner, Zool. Jahrb., 57:184, 1929; Stuart, Occas.

Papers Mus. Zool. Univ. Michigan, 292:5, June 29, 1934; Dunn, Copeia, no. 4:214, December 31, 1937.

_Conophis lineatus similis_ Smith, Journ. Washington Acad.

Sci., 31:123-124, March 15, 1941 (Type.--United States National Museum, No. 79963; type locality.--Managua, Nicaragua; _nec_ Bocourt _in_ Dumeril, Bibron and Mocquard, Mission Scientifique au Mexique et dans l'Amerique Centrale, 2:647-648, 1886); Cochran, Bull. U. S. Natl. Mus., 220:167, 1961.

_Conophis lineatus dunni_ Smith, Proc. U. S. Natl. Mus.

92:394-395, November 5, 1942; Savage, Trans. Kansas Acad. Sci., 50:483-486, December 31, 1949; Taylor, Univ. Kansas Sci. Bull., 34(pt. 1):145, October 1, 1951; Neill and Allen, Publ. Res.

Div. Ross Allen's Rept. Inst., 2:56, November 10, 1959; Herpetologica, 16:146-148, fig. 2, September 23, 1960.

_Conophis pulcher pulcher_, Stuart, Misc. Publ. Mus. Zool.

Univ. Michigan, 69:79, June 12, 1948; Contr. Lab. Vert. Biol.

Univ. Michigan, 45:24, May, 1950; Contr. Lab. Vert. Biol.

Univ. Michigan, 49:14, August, 1951; Contr. Lab. Vert. Biol.

Univ. Michigan, 65:19-20 (part), March, 1954.

_Conophis pulcher plagosus_, Mertens, Zool. Anz., 148:93, February, 1952; Abhand. Senken. Naturw. Gesell., 487:61-62, December 1, 1952.

_Conophis lineatus nevermanni_, Taylor, Univ. Kansas Sci.

Bull., 37(pt. 1):563-565, fig. 16, October 15, 1955.

_Type._--United States National Museum, no. 79963, obtained by Lt. H.

C. Kellers. Type locality: Managua, Nicaragua. There are also three paratypes; one a topotype (USNM 79964), one from "Nicaragua" (USNM 25237), and one from Esparta, Costa Rica (USNM 37758).

_Diagnosis._--Lateral dark stripe anteriorly pa.s.sing through eye and posteriorly involving 3rd and 4th scale-rows; 1st scale-row darkly pigmented; no paravertebral dark stripe, although vertebral row sometimes darkly pigmented; six to thirteen stripes at mid-body; eight supral.a.b.i.als immaculate or having dark ventral margins.

_Variation._--Thirty-six specimens have 159 to 178 (167.2 4.56) ventrals. Thirty of these snakes having complete tails have 60 to 80 (70.5 5.36) subcaudals; the number of ventrals plus subcaudals varies from 224 to 247 (237.6). In 36 specimens the reduction from 19 to 17 dorsal scales takes place between ventrals 91 and 111 (102.1 4.59). s.e.xual dimorphism is evident in the number of subcaudals; 16 females have 60 to 72 (67.1), and 14 males have 67 to 80 (74.5) subcaudals. The largest specimen (ERA-WTN BH-300) is a female from Augustine, British Honduras, having a body length of 732 mm., a tail length of 183 mm. and a total length of 915 mm. A juvenile (MCZ 49794) from Tegucigalpa, Honduras, has a body length of 162 mm., a tail length of 51 mm. and a total length of 213 mm.

The greatest variation is in coloration. The ground-color is pale brown or white with dark stripes of black or deep brown present dorsally and laterally. Some specimens from Costa Rica have as many as 13 dark stripes at mid-body (fig. 1, C). In these snakes the first row of dorsal scales bears a series of large, slightly elongated, dark spots; on the 2nd row a narrow dark brown stripe on the middle of the scales; on the 3rd a black stripe on the dorsal one-third to one-half of the scales; on the 4th and the 7th rows black stripes on the medial half of the scales of each row; on the 8th and 10th (vertebral) rows dark brown stripes on the medial third of the scales of each row. A specimen from Guatemala (UMMZ 107339) shows the greatest reduction of stripes and dark pigmentation (fig. 1, A); it has only eight stripes at mid-body: on the first row of dorsal scales a discontinuous stripe is formed by a series of dashes; the 3rd row bears a series of small black spots near the base and tip of each scale; the 4th and 7th rows bear continuous black stripes on the medial third to fourth of the scales of each row; the 8th row has extremely small dark spots near the tips of some scales.

The primary stripes, characteristic of the species _lineatus_, are those on the 1st, 4th and 7th rows of dorsal scales; these are the most prominent stripes. In some specimens these primary stripes begin as spots or dashes on the nape and become continuous stripes posteriorly; in others they are continuous for the length of the body.

The stripe on the 1st row is most variable; usually it consists of only a discontinuous series of dashes for most of its length. The secondary stripes are those on the 3rd and 8th rows; of these, only the one on the 3rd scale-row is present on the nape. The stripe on the 3rd row in combination with the dark stripe on the 4th row is the posterior continuation of the dark stripe that on the head pa.s.ses through the eye; this stripe is characteristic of _C. lineatus dunni_.

Both secondary stripes usually begin anteriorly as a series of spots or dashes and become continuous stripes posteriorly; occasionally near the base of the tail they fuse with the primary stripes on the 4th and 7th rows. In some specimens in Costa Rica indistinct stripes are present on the 10th (posteriorly the 9th) rows, and in some specimens in Honduras, Nicaragua, and Costa Rica similar indistinct stripes are present on the 2nd row.

Usually there are more or less conspicuous dark spots laterally on the ventrals, but in some specimens there are no spots. Except for the dark lateral spots (when present) the ventrals are immaculate white.

The dorsal ground-color is a pale brown or brownish white in preserved specimens on the 1st, 2nd, 3rd and 4th rows of scales where dark stripes or spots are not present. The ground-color of the dorsum between the 5th rows on each side is a somewhat darker shade of pale to medium brown.

Never is more than the lower one-third of each of the supral.a.b.i.als brown. In many specimens little or no brown is present on the lower margins of these scales. Some of the specimens having brown on the supral.a.b.i.als also have dusky markings of tan or gray on the chin and infral.a.b.i.als. Specimens from the northern part of the range (Guatemala) less frequently have dark chins and supral.a.b.i.als than do specimens from the southern part of the range (Costa Rica). There is, nevertheless, at any one locality considerable variation in the amount of dark pigmentation present on the chin and supral.a.b.i.als, thereby indicating that the slight geographic trend in this character is not significant.

Probably the most common pattern of dorsal coloration consists of eight or ten dark stripes (fig. 1, B). In snakes having this pattern the stripes on the 1st, 3rd, 4th and 7th rows are always present and prominent, although those on the 1st and 3rd rows sometimes are present as discontinuous rows of dashes. The ground-color from the venter to the 7th row is usually pale brown, and that dorsally between the 7th rows on each side is usually a darker, medium brown. A series of spots or dashes or a continuous stripe is sometimes present on the 8th row of scales.

Snakes having a larger number of dark stripes and more dark pigmentation occur in the southern part of the range. There seems to be a cline from paler snakes having fewer stripes in the north to darker snakes in the south.

[Ill.u.s.tration: FIG. 3. Patterns of dorsal coloration at mid-body of juveniles of two sympatric species of _Conophis_.

A. _C. lineatus dunni_ (MCZ 49794) from Tegucigalpa, Honduras.

B. _C. pulcher_ (MCZ 49791) from Tegucigalpa, Honduras.

Approximately 1.]

In juveniles, there are six or eight black stripes boldly contrasting with a white or pale tan ground-color (fig. 3, A). The first pair of stripes is on the 1st scale-row; the second pair, on the 3rd and 4th scale-rows; the third pair, on the 7th row; the fourth pair (when present), on the 8th row. Ontogenetic change in coloration consists of the splitting of the second pair of dark stripes in the juvenile.

Additional stripes may form later on the 2nd and/or 10th rows of dorsal scales.

_Remarks._--Savage (1949:483-486) stated that his specimen of _C. l.

dunni_ (from Honduras) resembled _l. lineatus_ in having secondary stripes on the 2nd and 8th rows and dark pigmentation throughout the length of the 2nd row. As can be seen from the preceding discussion of variation, a specimen having this color pattern is clearly within the observed range of variation of _l. dunni_. The specimen in no way represents an intergrade between _C. l. dunni_ and _l. lineatus_.

A specimen in the British Museum (Natural History), catalogued in 1853 (no. 53.2.4.16), has the locality listed as "Mexico." Since this specimen is of _C. l. dunni_ and this subspecies occurs only south of Mexico, the locality must be considered erroneous; possibly the locality as recorded referred only to the fact that the specimen came from tropical Middle America.

The absence of paravertebral stripes, the presence of a lateral dark stripe on the nape involving the 3rd and 4th rows of scales, and the darkly pigmented 1st scale-row, in combination with the characteristics of the genus, distinguish _C. l. dunni_ from all other snakes in Mexico and Central America. The only sympatric species of this genus, _C. pulcher_, differs in that it has paravertebral stripes (though never a vertebral dark stripe). _Conophis pulcher_ has a lateral dark stripe that includes the upper half of the second scale-row on the anterior part of the body; stripes of _C. l. dunni_ never include more than the 3rd and 4th rows. Even as juveniles the paravertebral row is not darkly pigmented in _C. l. dunni_ as it is in _C. pulcher_.

_Distribution._--Semi-arid habitats from sea level to elevations of 1000 m. from the Cuilco Valley in western Guatemala, El Peten and British Honduras southeastward to northeastern and southern Honduras, western Nicaragua and northwestern Costa Rica (fig. 2).

_Specimens examined._--Total of 41 specimens, as follows: BRITISH HONDURAS: _Cayo District_: Augustine, ERA-WTN BH-300; _Mountain Pine Ridge, 10 mi. E Augustine_, ERA-WTN BH-298.

COSTA RICA: _no specific locality_, AMNH 17309. "_Cartago_," BMNH 71.11.22.15. _Puntarenas_: 32 km. N Barranca, KU 35630; Esparta, USNM 37758. "_San Jose_," ANSP 3480, 12232.

EL SALVADOR: _Morazan_: El Divisadero, CNHM 10999. _San Miguel: San Pedro_, MCZ 57061.

GUATEMALA: _El Peten_: Sojio (Toocog), AMNH 69969, 69986.

_Huehuetenango_: flood plain Rio Cuilco, W of Finca Canibal, 18 km. N Tacana, UMMZ 98283. _Santa Rosa_: Santa Rosa, UMMZ 107339.

HONDURAS: _no specific locality_, AMNH 32814, UF 7657. _Cortes: Cofradia_, SU 8422; _Gracias_, CNHM 28560; _Hacienda de Santa Ana, W San Pedro Sula_, CNHM 5297; San Pedro Sula, UMMZ 68695(2); _near San Pedro Sula_, MCZ 27563. _Francisco Morazan: Potrero de Melio, Escuela Agricola Pan-americana_, MCZ 49987; Tegucigalpa, MCZ 49784, 49786, 49789-90, 49792, 49794.

MeXICO: _no specific locality_, BMNH 53.2.4.16.