Photo by Patrick Briggs
MID-BAJA CALIFORNIA GOPHER SNAKE
(Blainville, 1835 for vertebralis) (Klauber, 1946 for bimaris)
Pituophis vertebralis bimaris= (Pituophis catenifer bimaris)
By Patrick Briggs
When additional material that seemed significant became available to better describe Pituophis relationships occurring in Baja California, Laurence M. Klauber, Curator of Reptiles and Amphibians for the Society of Natural History decided to resurvey the snakes of the peninsula and reexamined the collections of various institutions. As a result, he formed 4 new subspecies that he described for the Society in 1946. One of them he called Pituophis catenifer bimaris which was similar to Pituophis catenifer vertebralis.
Some authorities currently disagree on the systematics of the Baja California gopher snake forms and relegate Pituophis catenifer vertebralis and Pituophis catenifer bimaris to synonomy as one species, Pituophis vertebralis composed of two pattern classes. Lee Grismer of La Sierra University in Riverside California and his collegues also consider (vertebralis) a distinct species separate from the (annectens) race of Pituophis catenifer, because the two forms overlap in distribution for nearly 180 kilometers in the northern part of Baja California, yet show no signs of interbreeding. Interestingly, Rodriguez-Robles and Jesus-Escobar (2000) consider vertebralis to be catenifer based on DNA sequence data. On this website, until it becomes more apparent, vertebralis will be used in reference to the species and both bimaris and vertebralis will refer to subspecies.
The bimaris form is closely related to vertebralis form. Bimaris differs in at least one aspect by its black or dark brown anterior blotches versus the red or reddish brown blotches found in vertebralis. Its overall color is generally less brilliant or drab in comparison to the intense reds generally desplayed by the vertebralis form.
Pituophis vertebralis bimaris is 36-60 inches (90-178 cm). The head is wedge-shaped and moderately distict from the neck when view from above and is light brown with few marks if any, and with a postorbital stripe that is faint or gone instead of being prominent. The margins of the labials are not edged in black. The eyes are somewhat protuberant with round pupils. Subcylindrical in its cross section, the body is variably marked with 34-46 black or brown biconcave dorsal blotches within a body ground color of shades of tan, straw-yellow, or cream. L. Grismer indicates that this subspecies' (pattern class) color intensifies with age and has more red-orange color at San Ignacio and southward. The anterior dorsal black blotches extend from one blotch to another on both sides surrounding the lighter interspaces forming enclosed round spots. There are 8-15 markings on the upper tail. The spotting along the sides are confluent and similar with those above anteriorly. They isolate the first interspaces forming light spots within a solid black band like those of most deserticola. Unlike deserticola, the spots are not dark streaked. The belly is pale from white to a faint yellow. The dark dorsal blotching is black or bolder towards the head and tail ends, while the mid-body region is often mohagany or brown and more faintly marked. Tails are longer in males which house the hemipenes. The underside of the tail exibits a black subcaudal stripe.
The Taxonimic Terms:
Herpetoculturists have been breeding these two forms of Baja California gopher snake for many years. They refer to them as "vertebralis" or "bimaris", so many ophidian enthusiasts are already familiar with these taxonomic terms. The specific or latter portion of the scientific epethit Pituophis vertebralis gets its name VERTEBRALIS from the Latin modification of the word which means "pertaining to the back". BIMARIS means "two seas" in reference to the Baja California peninsula located between the Gulf of California and the Pacific Ocean where this form is found.
This species with its two forms or races occurs commonly throughout the Vizcaino, Central Gulf Coast, Sierra la Laguna area, and arid to tropical areas in Baja California from 43 Kilometers by the road south of El Rosario to southern tip of the cape region of of Baja California Sur. It's also been reported from smaller islands such as Isla San Jose of the the gulf region, Magdelena, and along the Pacific coast; Santa Margarita. Its range apparently does not include outside the central highlands into the lower Colorado Valley Region of northeastern Baja California.
Rocks and boulders with brush and Cacti, Oceanside rocky banks and boulders, Oceanside rocky banks and boulders to about 1,200′, Baja California, Mexico
The P. v. bimaris subspecies ranges from Valle la Trinidad south to the Isthmus of La Paz. It reportedly intergrades with P. v. vertebralis between La Paz of the Cape Region and La Presa Region(L. Grismer 2002, Sweet and Parker 1990).
Pituophis vertebralis bimaris constricts feeding primarily on young or small mammals and birds. Even so, there are reports of small frog species such as Hyla regilla and lizards such as Uta stansburiana that are also prey to this species. In captivity, cannibalism has been reported and gopher snakes have been photographed eating others of their same species. Occassionally, other smaller snakes species are also eaten.
Visit the San Diego Museum site for the holotype below:
SDSNH Cat. No. 32621 http://www.sdnhm.org/archive/research/herpetology/record_detail.php?herp_id=92
See a good resource: AMPHIBIANS and REPTILES of BAJA CALIFORNIA
INCLUDING ITS PACIFIC ISLANDS AND THE ISLANDS IN THE SEA OF CORTES
L. Lee Grismer 2002 (pages 297-300)
Pituophis vertebralis bimaris
Scutelation: Imbricate Dorsal Scales with Vertebral Rows Sharply Keeled
Mid-body 31-35 usually 33 Supralabials 8-10 5th usually contacts eye
Ventrals 238-251 males Infralabials 11-15 (usually 13)
Ventrals 246-257 females
Subcaudals 60-72 males Preoculars 2
Subcaudals 56-63 females
Anal divided plate Postoculars 3-5
Prefrontals 4 sometimes inners fused to the outer to form 2 very wide
1st Temporals 3-6
Pituophis vertebralis bimaris Mid-Baja California Gopher Snake (below)
Photo by Patrick Houston Briggs Courtesy John Ginter
Mid-Baja California Gopher Snake Head Study Photo by Patrick Houston Briggs Courtesy John Ginter
Mid-Baja California Gopher Snake Photo by Patrick Houston Briggs Courtesy John Ginter
The image ABOVE, the MID-BAJA or BIMARIS pattern class (as herpetologist Grismer refers to it) is found over most of the Baja California Peninsula from central Baja California Norte to close visinity of La Paz, Baja California Sur. It lacks the grayish suffusion along the laterals and sports less than 50 dark dorsal markings with a darker less brilliant look than the other pattern class.
Pituophis vertebralis bimaris
Scanned Slide image by Pat Briggs Courtesy John Ginter
See this site image of bimaris: http://www.inaturalist.org/taxa/29050-Pituophis-catenifer-bimaris
Bimaris from Lat. 24' 21' N. to Lat. 30' N. (T. Moisi)