B. c. ortonii
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We wish to thank Dennis Sargent for kindly providing this description.


May 4, 1877.                                                                                                                                   (Cope)

Synopsis of the Cold Blooded Vertebrata, procured by Prof. James Orton during his Exploration of Peru in 1876-77.

 By E. D. Cope 

(Read before the American Philosophical Society May 4, 1877.)






12.       BOA ORTONII, Cope, sp. Nov.

  This species is intermediate in character between the Boa constrictor and the Boa imperator.  It has the stout proportions of both species, while the squamation of the head is like that of the former, and that of the body resembles that of the latter.  There are no large scuta on the loreal or orbital regions, and the scales of the head generally are characterized by their small size.  The characters of the species are best brought out in a comparative table, which I give :


  Sect I.  89-95 rows of scales on the body.

  Orbital ring not in contact with labials, gastrosteges 234-40;

urosteges 49-56………………………………………………………..B. constrictor.

  Sect. II.  55-69 rows of scales.

  a  Orbital series separated from labials by a row of scales;

No large loral plate; form stout; g. 252, u. 53; labials 19;

orbital ring composed of 19 scales; 64 rows on the body……………..B. ortonii.

  aa   Orbital ring reaching labials.

No large loral plate; stout; u. 56; 57-62 rows on body;

Orbitals 13-17…………………………………………………………B. imperator.

  A loral plate as large as the orbit; proportions as in the last…………B. eques.

  No large loral plate; form elongate; g. 272; u. 69……………………B. diviniloqua.


  With the typical specimen I associate one from Greytown, Nicaragua, which agrees with it in the generally smaller size of the scales of the head and body than is found in the B. imperator, the usual Mexican species.  It has 69 rows of scales; 21 labials and 17 scales in the orbital ring; gastrosteges 242.

  No. 1 from Chilete, near Pacasmayo, 3000 feet above the sea.  This species is dedicated to Professor James Orton, whose explorations of the western regions of South America have yielded such abundant results.

We would like to thank Jim Pomaville (translated by William Joy) for kindly providing this material.

Boa constrictor ortonii  Cope

  1878.---Boa ortonii, Cope; Proc. Amer. Phil. Soc., 17, p. 35, Chilete near Pacasmayo.

  1923.---Constrictor constrictor, Dunn; Proc. Biol. Soc. Wash. Vol. 36, p. 186, Perico and Rio Maranon.

  1943.---Constrictor constrictor ortonii, Schmidt and Walker Jr., Field Mus. Nat. Hist., Vol. 24, No. 27, pp. 305-306.

  1947.---Constrictor constrictor ortonii, Prado and Hoge, Mem. Inst. Butantan XX, p. 284.

    MATERIAL STUDIED.---1 adult male (Of. 155), Trujillo (State of La Libertad), (Fig. 19) and adult female (Of. 50), Chanchamayo (State of Junin).

    SPECIMANS  EXAMINED.---A total of 2 (see table no. 6).

    COMMON NAME.---Boa.

    SPECIES CHARACTERS.---Anterior mandibular and maxillary teeth larger than the rest, gradually decreasing in size.

  The head presents three dark brown stripes, one medial with faint lateral projections beginning behind the rostral, running between the eyes where it widens, joining the first band on the body; the remaining two are wide, beginning near each nostril, encompassing the first supralabials until touching the preoculars, continuing behind the eyes going down through the corner of the mouth until reaching near the neck, (fig. 18-c).  In the juvenile specimen a narrow dark brown bar is seen beneath the eye.

  Rostral slightly wider than it is tall, barely visible from above.  Nasals separated by tiny scales.  Head with tiny scales slightly larger than the snout, one of the preoculars a little larger than the rest.  Orbital scales number from 16 to 18 and 14 small scales cross the forehead from eye to eye.  There is no loreal scale; instead there are 9 to 10 tiny scales between the nostril and the eye.  The orbitals are separated from the supralabials by a row of scales on both sides of the head.  Labial pits are not present.

    COLORATION.---The whole body has a light brown color in both sexes (male #29 and female #29) hexagonal shaped transverse on the dorsum, wider than in Boa constrictor constrictor Linnaeus, dark brown in color, with light colored longitudinal lines on the wider part, one on each end; on the tail of the adult male specimen two dark bands can be seen near the anus and the remainder has an irregular dark brown colored shape.  Ovoid or rhomboid designs on the sides with one or two light colored spots in the center.  Beneath the ovoid or rhomboid designs are smaller dark spots that go down until they reach the ventral scales.  Venter pink with sparse, dark flecks.

  SCALATION.---29 transverse bands on the body. Dark median line on the head with faint lateral projections between the eyes.  57-72 dorsal scale rows, with dark brown areas on the tail.  243-253 ventrals.  42-59 subcaudals.  19-20 supralabials.

   DISTRIBUTION.---From Perico and the upper valley of the Maranon, Pv. Jaen (State of Cajamarca) to Piura and toward the south to La Libertad, in the arid region of northwestern Peru (according to Dunn) and the Chanchamayo Valley (State of Junin, central Peru).

  Note.   This is an extremely rudimentary description but it is the only material I have been able to find.  If you can provide the original description or more data we would be interested in hearing from you.

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