specific locality_, CNHM 22912, NMW 16830. _Jutiapa_: Hacienda Mongoy,
UMMZ 106725. _El Progreso_: El Progreso, CAS 67000; _El Rancho_, UMMZ
106724; _San Antonio_, CAS 66999. "Peten," USNM 6751(2), 6803.
_Sacatepequez_: Duenas, BMNH 64.1.26.17, 64.1.26.126-127. _Zacapa_:
Pepesca, AMNH 72555-56.
HONDURAS: _no specific locality_, AMNH 58364. _Cortes_: San Pedro
Sula, CNHM 5295-96. _Francisco Morazan: El Zamarano_, AMNH 70189;
Tegucigalpa, MCZ 49785, 49787-88, 49791, 49793, 49795.
MEXICO: _Chiapas_: _Soconusco_, UIMNH 33646-47; Tonala, USNM 109707.
=Conophis vittatus= Peters
_Tomodon lineatum_ (in part), Dumeril, Bibron and Dumeril,
Erpetologie Generale, 7(pt. 2):936-938, February 25, 1854.
_Conophis vittatus_ Peters, Monatsb. Akad. Wiss. Berlin, pp.
519-520, pl., fig. 3, October, 1860; Cope, Proc. Amer.
Philos. Soc., 11:162, 1870; Bocourt _in_ Dumeril, Bocourt and
Mocquard, Mission Scientifique au Mexique et dans l'Amerique
Centrale, 2:644-646, pl. 38, fig. 7, 1886; Guenther, Biologia
Centrali-Americana, p. 165, March, 1895; Boulenger, Catalogue
of the Snakes in the British Museum (Natural History),
3:123-124, 1896; Cope, Amer. Nat., 30:1024, 1896; Ann. Rept.
U. S. Natl. Mus. for 1898, pp. 1094-1095, 1232, 1900; Gadow,
Proc. Zool. Soc. London, 2:225, 1905; Amaral, Mem. Inst.
Butantan, 4:211, 1929; Gadow, Jorullo, p. 55, 1930; Smith,
Zool. Ser. Field Mus. Nat. Hist., 24:31-32, January 30, 1939;
Taylor and Smith, Univ. Kansas Sci. Bull., 25:252-253, pl. 23,
July 10, 1939; Stuart, Contr. Lab. Vert. Biol. Univ. Michigan,
65:23, March, 1954; Alvarez del Toro, Reptiles de Chiapas, pp.
153-154, 1960.
_Conophis lineatus_ Cope, Proc. Acad. Nat. Sci. Philadelphia,
16(3):167, 1864 [_nec_ Dumeril, Bibron and Dumeril,
Erpetologie Generale, 7(pt. 2):936-938, atlas, pl. 73,
February 25, 1854; specimen from Colima]; Sumichrast, Arch.
Sci. Nat., p. 246, 1873.
_Tomodon vittatus_, Bocourt, Journ. de Zool., p. 407, 1876.
_Conophis sumichrasti sumichrasti_ Cope, Journ. Acad. Nat.
Sci. Philadelphia, ser. 2, 8:137, 1876 (Types.--United
States National Museum, nos. 29123, 30258; type
locality.--Tehuantepec, Mexico); Bull. U. S. Natl. Mus.,
32:77, 1887; Smith and Taylor, Univ. Kansas Sci. Bull., 33(pt.
2):334, March 20, 1950; Maldonado-Koerdell, Inst. Mexicanos
Recursos Nat. Renov., p. 124, 1953.
_Conophis sumichrasti viduus_ Cope, Journ. Acad. Nat. Sci.,
Philadelphia, ser. 2, 8:137, 1876 (Type.--United States
National Museum, no. 30259; type locality.--Tehuantepec,
Mexico); Bull. U. S. Natl. Mus., 32:77, 1887; Cochran,
Bull. U. S. Natl. Mus., 220:167, 1961.
_Conophis sumichrasti_, Cope, Proc. Amer. Philos. Soc.,
18:271, August 11, 1879; Sumichrast, Bull. Soc. Zool. France,
p. 182, 1880; Cope, Trans. Amer. Philos. Soc., 18:194, April
15, 1895; Cochran, Bull. U. S. Natl. Mus., 220:167, 1961.
_Tachymenis lineata_ (in part), Garman, Mem. Mus. Comp. Zool.,
8:60-61, July, 1884.
_Conophis vittatus sumichrasti_, Cope, Ann. Rept. U. S. Natl.
Mus. for 1898, p. 1095, 1900.
_Conophis vittatus videns_ Cope, Ann. Rept. U. S. Natl. Mus.,
for 1898, p. 1095, 1900 (apparent _lapus_ for _viduus_).
_Conophis vittatus vittatus_, Cope, Ann. Rept. U. S. Natl.
Mus. for 1898, p. 1095, 1900; Smith, Journ. Washington Acad.
Sci., 31:119-120, March 15, 1941; Proc. U. S. Natl. Mus.,
92:395, November 5, 1942; Proc. U. S. Natl. Mus., 93:408,
October 29, 1943; Ann. Carnegie Mus., 30:91, November 2, 1944;
Smith and Taylor, Bull. U. S. Natl. Mus., 187:44, October 5,
1945; Smith, Rev. Soc. Mexicanos Hist. Nat., 7:71, December,
1946; Smith and Taylor, Univ. Kansas Sci. Bull., 33(pt.
2):331, March 20, 1950; Davis and Smith, Herpetologica, 8:134,
January 30, 1953; Maldonado-Koerdell, Inst. Mexicanos Recursos
Nat. Renov., p. 130, 1953; Peters, Occas. Papers Mus. Zool.
Univ. Michigan, 554:22, June 23, 1954; Duellman, Occas. Papers
Mus. Zool. Univ. Michigan, 560:15, October 22, 1954; Webb and
Fugler, Herpetologica, 13:35, March 30, 1957; Duellman, Occas.
Papers Mus. Zool. Univ. Michigan, 589:15, March 21, 1958;
Zweifel, Amer. Mus. Novitates, 1949:2, 5, June 17, 1959;
Duellman, Univ. Kansas Publ. Mus. Nat. Hist., 15(1):91-92,
December 20, 1961.
_Conophis vittata_, Gadow, Proc. Zool. Soc. London, 2:196,
1905; Through Southern Mexico, p. 181, 1908.
_Conophis viduus_, Smith, Zool. Ser. Field Mus. Nat. Hist.,
24:31, January 30, 1939; Hartweg and Oliver, Misc. Publ. Mus.
Zool. Univ. Michigan, 47:26-27, July 13, 1940.
_Conophis vittatus viduus_, Smith, Journ. Washington Acad.
Sci., 31:120-121, March 15, 1941; Proc. U. S. Natl. Mus.,
92:395, November 5, 1942; Proc. U. S. Natl. Mus., 93:408,
October 29, 1943; Woodbury and Woodbury, Journ. Washington
Acad. Sci., 34(11):370, 1944; Smith and Taylor, Proc. U. S.
Natl. Mus., 187:44, October 5, 1945; Univ. Kansas Sci. Bull.,
33(pt. 2):340, March 20, 1950; Werler and Smith, Texas Journ.
Sci., 4:565, fig. 16, December 30, 1952; Maldonado-Koerdell,
Inst. Mexicanos Recursos Nat. Renov., p. 130, 1953; Davis and
Dixon, Proc. Biol. Soc. Washington, 72:82-83, July 24, 1959.
_Conophis vittatus vittatus_ x _Conophis vittatus viduus_,
Alvarez del Toro and Smith, Herpetologica, 12:13, March 6,
1956.
_Type._--Zoologisches Museum Berlin. Type locality not given, for the
specimen was purchased from a dealer in Hamburg. The type locality was
first restricted to "Acapulco," Guerrero, by Smith (1941:119), then to
Laguna Coyuca, Guerrero, Mexico, by Smith and Taylor (1950:331).
_Diagnosis._--Three or four dorsal dark stripes, each involving two or
more adjacent scale-rows; never having brown or black on the 1st
scale-row; seven supralabials immaculate white or pale tannish-white.
_Variation._--One hundred seventy-one specimens have 149 to 181 (163.7
+- 6.33) ventrals. One hundred fifty-three of these having complete
tails have 55 to 76 (64.8 +- 4.90) subcaudals; the number of ventrals
plus subcaudals varies from 214 to 245 (228.5). In 170 specimens the
reduction from 19 to 17 dorsal scales takes place between ventrals 84
and 118 (102.3 +- 6.60). Sexual dimorphism is evident in the number of
subcaudals; 58 females have 55 to 66 (60.0) and 95 males have 59 to 76
(67.8) subcaudals. The longest specimen (AMNH 68004) is a male from
Escurano, Oaxaca, Mexico, having a body length of 668 mm., a tail
length of 182 mm. and a total length of 850 mm. A juvenile (CNHM
40435) from Tehuantepec, Oaxaca, Mexico, has a body length of 133 mm.,
a tail length of 31 mm. and a total length of 164 mm.
Variation in coloration is of such magnitude that it has been used as
the basis for recognition of subspecies. Unfortunately, until this
time, most specimens reported upon in the literature represented the
two extremes of variation. After examining the coloration of 174
specimens with respect to geographic distribution, I conclude that
only one highly variable species is represented. Specimens from the
northern and western parts of the range (Michoacan, Colima, and
Durango) have the color pattern of _C. vittatus_ as described by
Peters (1860:518-521); these snakes have four narrow black stripes on
a white or pale tan background, and an immaculate white venter. The
lateral dark stripe, which on the head passes through the eye, is
present on the dorsal half of the 3rd and the ventral half of the 4th
scale-rows; the dorsolateral dark stripe, which passes along the
middle of the head and splits on the nape, is present on the middle of
the 8th scale-row. The other extreme in color pattern consists of
three broad stripes; the two dorsolateral stripes are fused. This
pattern is prevalent in specimens from the area around Tehuantepec,
Oaxaca. The lateral stripes include the dorsal half to two-thirds of
the 2nd, all of the 3rd and 4th, and half of the 5th scale-rows; the
fused dorsolateral stripes sometimes cover all of the area dorsal to
and including the dorsal third of the 7th scale-row.
Snakes from areas between Tehuantepec and the margins of the
distribution of this species are variously intermediate between the
extremes described above. In some snakes from these areas the lateral
stripes are broad and include either the dorsal half of the 2nd
scale-row or the ventral half of the 5th scale-row, but not both on
the same specimen. Also, the dorsolateral stripes are broad and
include most of the 9th and a part of the 10th scale-rows. Many
specimens from the area around Tehuantepec, where the three-striped
pattern is prevalent, have an intermediate pattern. Some have white on
the center of the 10th scale-row or lateral stripes that are not so
broad as to include the 3rd and 4th and half of each of the 2nd and
5th scale-rows.
The supralabials are immaculate white or pale tan, except that in some
specimens the dorsalmost part of some supralabials are dark brown or
black as they are included in the ventral boundary of the dark stripe
that passes through the eye. There are no dusky markings on the chin
or on any of the ventral scales.
There is no ontogenetic change in color pattern; juveniles have the
same coloration as adults from the same geographic area.
Color in life is not greatly different from that of preserved
specimens. One specimen (UMMZ 114483) from 10.8 miles south of Oaxaca,
had in life black stripes, a pale yellowish tan dorsal ground-color
and a pale off-white venter.
An excellent photograph of this species appears in Schmidt and Inger
(1957:230) under the name _Conophis lineatus_.
_Remarks._--I have been unable to find variation of geographic
importance in scutellation in this species. A wide range of variation
in the characters of scutellation is present in specimens from most
localities; it shows no significant clinal or geographic trends. As I
have stated previously, in the discussion of variation, coloration has
been the feature primarily used by previous workers to distinguish two
"subspecies" for this species; _C. vittatus vittatus_ having four
black stripes and _C. vittatus viduus_ having three black stripes.
Most of the three-striped snakes occur in the vicinity of Tehuantepec,
Oaxaca, whereas the four-striped snakes are found near the margins of
the range of the species in Durango, Colima, Michoacan, Morelos and
Puebla. Specimens that would have to be considered intergrades between
the "subspecies" are found in Michoacan, Guerrero, Oaxaca and Chiapas.
At the time the subspecies were proposed only specimens from
Tehuantepec or from marginal areas were known. Utilizing the large
number of specimens of this species presently available, geographic
variation is found to be clinal, from those with three stripes from
near Tehuantepec, through several intermediate patterns present on
specimens from single localities in Guerrero, Oaxaca and Chiapas, to
those with four dark stripes in areas farthest removed to the north
and west from Tehuantepec. Since only coloration shows geographic
variation, and since this variation represents a continuous cline,
subspecies cannot be recognized for this species.
The presence and position of the three or four dark stripes on the
body and the absence of brown on the 1st scale-row or on the ventral
scales, in combination with the generic characters, distinguish
_Conophis vittatus_ from all other Mexican snakes. The only other
snake that occurs in western Mexico that has been confused with _C.
vittatus_ is _Coniophanes piceivittus taylori_, which has 25, instead
of 19, scale-rows.
_Distribution._--Semi-arid habitats on Pacific slopes from extreme
southern Durango southeastward to Tuxtla Gutierrez, Chiapas, and
inland in the eastern Balsas Basin to Morelos and western Puebla
(fig. 5).
[Illustration: FIG. 5. Selected locality records for _Conophis
vittatus_.]
_Specimens examined._--Total of 174, as follows: MEXICO: _no specific
locality_, AMNH 66150-52, SU 9465. _Chiapas_: Piedra Parada, USNM
121453. _Pizo de Oro_, UIMNH 40821. Tuxtla Gutierrez, Parque Madero,
UIMNH 37992-93, 38036-37. _Colima: no specific locality_, MCZ 46860,
USNM 31394, 31396-97. 1 mi. SW Colima, AMNH 12783. S of Manzanillo,
AMNH 19641. _Durango_: Hacienda de Gabriel, AMNH 14217. _Guerrero:
Acahuizotla_, TCWC 7419, 9469. _1 mi. W Acahuizotla_, TCWC 7418. 3 mi.
W Acapulco, AMNH 71626. _6 mi. E Acapulco_, TCWC 9476-77. _10 mi. S
Acapulco_, TCWC 8578. _Agua del Obispo_, CNHM 104948, TCWC 11586. near
Chilpancingo, MVZ 45067, UMMZ 85722-23. _1 mi. SW Colotlipa_, TCWC
9471-74. _2 mi. SW Colotlipa_, TCWC 9475. 14 mi. S Ixtapan de la Sal,
KU 67648. _Laguna Coyuca_, CNHM 25881, UMMZ 80942. near La Union, AMNH
66337. _Magueyes, Laguna Coyuca_, AMNH 66149. _Playa Encantada_, TCWC
9470. 1 mi. S Tierra Colorada, KU 67649. near _Xaltinanguis, km. 405_,
CNHM 104947. _Michoacan_: Coalcoman, UMMZ 104693. _1/2 mi. SE
Coalcoman_, UMMZ 104492. _1 mi. N. Coalcoman_, UMMZ 112543. _1 mi. NE
Coalcoman_, UMMZ 104692. Puerta de la Playa, UMMZ 105155. 12 mi. S
Tzitzio (by road), UMMZ 99153. _Morelos: 12 km. NW Axochiapan_, TCWC
7311, UIMNH 17613, 25924. 7 mi. SE Cuernavaca, MVZ 32258. _Huajintlan,
km. 133_, CNHM 103270. 12 km. S Puente de Ixtla, km. 133, CNHM 104949.
_Oaxaca: Bisiliana_, AMNH 68010. _near Caoba, foot of Cerro Arenal_,
AMNH 68009. _Cerro Arenal_, AMNH 68000-03. _Cerro de Laollaga_, UIMNH
36213. _Cerro de San Pedro_, UIMNH 17616. _Cerro Palma de Oro_, UIMNH
37116. "_C. Madrena, Sto. T. Quieri_," UIMNH 46904. near Chivela, MCZ
25021. Cinco Cerros, UIMNH 37114. _Dami Liesa_, AMNH 66877, UIMNH
6158, 37115. _Escuranos_, AMNH 66873-74, 68004-06. _Finca Santa
Teresa, 2 km. NW Tehuantepec_, UMMZ 82648. _Huilotepec_, AMNH 66878,
UIMNH 40820. _between Huilotepec and Tehuantepec_, AMNH 65106, UMMZ
82644-45. _Las Tejas_, UIMNH 6151-54. _Mixtequilla_, UIMNH 6157,
36211. _between Mixtequilla Mountains and Tehuantepec_, UMMZ 82652.
_between Niltepec and "Carixxal,"_ AMNH 68876. 10.8 mi. SE Oaxaca,
UMMZ 114483. _Quiengola_, UIMNH 17617. _between Quiengola Mountains
and Tehuantepec_, UMMZ 82647. _Rancho Poso Rio, 6 km. S Tehuantepec_,
UIMNH 6144-49, 37117-19, UMMZ 82649-51. _Rincon Bamba_, CNHM
105129-30, UIMNH 17615. _Salazar_, AMNH 66875. _vicinity of Salina
Cruz_, UMMZ 82653. _San Geronimo_, AMNH 4306, CNHM 1457. _San Lucas
Ixtepec_, UIMNH 36206. San Juan Lajarcia, UIMNH 36212. San Mateo del
Mar, AMNH 65914. _San Pablo_, UIMNH 36207. _Santa Maria (Cerro de
Liesa)_, AMNH 68011. Tapanatepec, MCZ 27806-11. Tehuantepec, AMNH
19644, 65107-09, 65907-13 plus 7, 66871-72, 66879, 68007-08, CNHM
40435-36, 105126-28, MCZ 46403, UIMNH 6150, 17614, 17618, 29692,
36208, 37120-21, UMMZ 82642-43, 82646, USNM 109709-14, _1-2 leagues
SSE Tehuantepec_, UMMZ 82639-41. Tenango, UIMNH 36209-10. between
Tlacolulita and Tequisistlan, CNHM 105125. _Yerba Santa_, UIMNH
6155-56. Puebla: Atencingo, KU 39626.
Skull
In studying the osteology of the genus _Conophis_, I have examined
two complete skeletons (one _C. vittatus_ and one _C. lineatus_); two
additional skulls of _C. vittatus_ and _C. lineatus_; and 24 sets of
dentigerous bones, representing all of the species. Terminology
of the skeletal elements is that of Duellman (1958), Parker (1878),
Radovanovic (1937) and Szunyoghy (1932). The drawing of
the right side of the skull of a specimen of _Tomodon lineatus_ that
appears in Jan and Sordelli (1881:liv. 50, pl. 2, fig. 34) is of little
value due to its small size and lack of detail.
The skull of _Conophis_ is typical of a relatively unspecialized
colubrid snake. Skulls of _Conophis lineatus concolor_ and _C. vittatus_
closely resemble each other. The following description is based
primarily on the skull of _C. lineatus concolor_ (UMMZ S-778).
The elements are discussed in the following order: nasal region,
cranium and associated elements, maxillo-palatal-pterygoid arch,
mandible, dentition, and vertebrae.
[Illustration: FIG. 6. The skull, lacking dentigerous bones, of
_Conophis lineatus concolor_ (UMMZ S-788) showing (A) dorsal,
(B) lateral, and (C) ventral views. x 3.]
_Nasal region._--The premaxillary is relatively heavy and has a
concavity posteroventrally. The lateral processes slope downward, but
remain fairly thick, and do not project far laterally. This shape
(fig. 6) tends to strengthen the nasal region; this anterior
strengthening may be a reflection of the fossorial habits of these
snakes. There are no posterior processes of the premaxillary; thus the
line of fusion with the nasals and septo-maxillaries is broad. The
nasal plate is more than twice as long as wide. The nasals are
relatively flat above, although each curves slightly downward medially
and fuses into the medial nasal septum; laterally each nasal is
narrower and deflected downward, forming a small dorsal shield over
the nasal cavity. The septo-maxillaries are closely associated with
the vomers and form the cavity in which the organ of Jacobson is
situated. The broad medial part of the septo-maxillary forms the roof
and anterior border of the cavity, whereas the anterior part of the
vomer contains the main part of the capsule and forms the posterior
and most of the lateral borders of the cavity. The vomer has a thin
anterior ridge that gradually disappears before it reaches the border
of the premaxillary. The vomer is approximately U-shaped, when viewed
from below. It has no posterior process and does not articulate with
the parasphenoid; there is a sizeable gap between the two bones. The
septo-maxillary has a lateral process that terminally is directed
slightly anteriorly.
_Cranium and associated elements._--The frontal is almost three times
as long as it is wide; it is flat above with an emarginate
dorsolateral margin that forms the upper limit of the optic capsule.
Ventrally the frontal is concave and forms the median limits of the
optic cavity. Farther ventrally the frontal joins with the
parasphenoid, which at this place forms the ventral extent of the
skull, and together with the basisphenoid forms the ventral part of
the posterior three-fourths of the skull. In ventral aspect, the
parasphenoid is a long, thin bone, slightly expanded anteriorly. It
forms the anterior floor of the optic foramen; whereas the frontal
forms the anterior roof of the same opening. The frontal and its
septo-maxillary process surround the olfactory fenestra. The
prefrontal articulates with the anterolateral process of the frontal.
The posterior surface of the prefrontal forms the anterior wall of the
orbit of the eye. The articulating surface upon which the median
process of the maxillary bone rests is situated ventrally. The
anterior dorsal surface of the prefrontal, together with the
anterolateral edge of the frontal, extends slightly over the nasal
cavity, affording some degree of protection for the contained organs
and forming the posterior border of the cavity. A small nasal process
also extends anteriorly from the ventrolateral surface of the
prefrontal. The orbital-nasalis foramen is located in the anterior
surface of the prefrontal. The parietals are fused into one large bone
that forms the roof and sides of the middle part of the cranial
cavity. From its suture with the frontal, the dorsal surface of the
parietal is relatively flat in the area bounded laterally by the
parietal crests, which extend posteromedially from the anterolateral
corners of the bone and converge medially at a point near its
posterior margin. A slight posterior extension of the parietal crests
forms the supratemporal crest, which is present on the posterior part
of the parietal and on the anterior part of the supraoccipital. The
postfrontals are attached to the anterolateral processes of the
parietal. Together the anterior surfaces of these two bones form the
posterior rim of the orbit of the eye. The postfrontal extends
laterally and ventrally and has a terminal extension that projects
anterolaterally. In an articulated skull the trans-palatine articulates
with the ventrolateral articulating surface of the postfrontal.
Anteromedially, the parietal forms the roof and posterior margin of
the optic foramen. The basisphenoid, which is fused with the
parasphenoid, also forms a small part of the posteroventral margin of
the optic foramen. The basisphenoid forms the floor of the middle part
of the cranial cavity and the ventromedial down-pouching that
contains the pituitary body. Posterolateral to the parietal and dorsal
to the posterior part of the basisphenoid is the prootic. Laterally
this bone is deeply emarginate; posteriorly it forms a large part of
the otic notch, through which the columella passes. The columella is a
long, thin bony rod that terminates posteriorly in cartilage. It is
the cartilagenous part of the columella that connects with the
external sound detecting mechanism. There are several foramina on the
lateral surface of the prootic. On the anterolateral surface of the
prootic, branches of the trigeminal nerve pass through three foramina
whereas the facial nerve passes through the single posterior foramen
near the otic notch. The squamosal is attached dorsoventrally to the
posterior part of the parietal and to the lateral part of the prootic.
At this place of attachment there is on the prootic a relatively heavy
crest that forms a rather broad articulating base. The squamosal is
long, flat, and curves slightly in a dorsal direction throughout its
length; it becomes thinner and narrower posteriorly. The posterior
third of the squamosal forms a broad base by means of which the
squamosal articulates with the quadrate. The columella and the
squamosal extend posteriorly beyond the limits of the braincase.
Posteriorly the skull consists of four bones: an unpaired median
dorsal supraoccipital, an unpaired median ventral basioccipital and
two lateral exoccipitals. The basioccipital does not have noticeable
pterygoid processes, but is rather smooth ventrally and only slightly
emarginate on its posterolateral margins. Posteriorly, this bone forms
the ventral part of the occipital condyle. The rest of the condyle, on
each side, is formed by the exoccipitals. The exoccipitals also form
part of the base to which the squamosal is attached. The exoccipitals
extend around the sides of the foramen magnum and meet dorsally. Each
exoccipital also forms the posterior part of the otic notch, which
traverses the exoccipital. The exoccipitals bear moderate occipital
crests that extend posterolaterally across the supraoccipital as
branches from the supratemporal crest. The supraoccipital also has a
medial crest that extends a short distance posteriorly from the
supratemporal crest onto the exoccipitals at their dorsal line of
fusion.
[Illustration: FIG. 7. The maxillo-palatal-pterygoid arch of
_Conophis lineatus concolor_ (UMMZ S-788) showing (A) dorsal,
(B) lateral, and (C) ventral views. x 3. Teeth shown by means
of broken lines were represented only by their sockets.]