Subspecies
There are 10 current subspecies of Boa constrictor, however much of these are poorly differentiated and it is thought that further research will redefine many of these subspecies. Some appear to be based more on location than biological differences, such as B. c. orophias (the St. Lucia Boa).
| Subspecies | Taxon author | Common name | Geographic range |
|---|---|---|---|
| B. c. amarali | Stull, 1932 | Amaral's boa | Brazil, Bolivia and Paraguay |
| B. c. constrictor | Linnaeus, 1758 | Red-tailed boa | South America |
| B. c. imperator | Daudin, 1803 | Common northern boa | Central America and northern South America |
| B. c. longicauda | Price & Russo, 1991 | Tumbes Peru boa | Northern Peru |
| B. c. melanogaster | Langhammer, 1983 | Ecuadorian boa | Ecuador |
| B. c. nebulosa | (Lazell, 1964) | Dominican clouded boa | Dominica |
| B. c. occidentalis | Philippi, 1873 | Argentine boa | Argentina and Paraguay |
| B. c. orophias | Linnaeus, 1758 | St. Lucia boa | St. Lucia |
| B. c. ortonii | Cope, 1878 | Orton's boa | South America |
| B. c. sabogae | (Barbour, 1906) | Pearl Island boa | "Pearl Islands" off the coast of Panama |
There have also been several other subspecies described at different times, but currently these are no longer considered to be subspecies by many herpetologists and taxonomists. These include:
- Boa constrictor mexicana (Jan 1863): This was described from a single specimen which had 55 dorsal scale rows, but otherwise appeared the same as a B. c. imperator. Since then B. c. mexicana has been included within the B. c. imperator subspecies by most authors, as Smith (1963) commented that no Mexican boas have been proven to have 55 dorsal scale rows. However, there is still controversy as Andrew (1937) reported four Mexican specimens with dorsal scale rows between 56–62.
- Boa constrictor eques (Eydoux & Souleyet, 1842): Based upon a single specimen from Peru that had one large orbital scale. However, no other such specimens have been found and it is thought that the snake was an aberrant B.c.imperator.
- Boa constrictor diviniloqua (Duméril & Bibron, 1844): Now known to be synonymous with B. c. orophias.
- Boa constrictor sigma (Smith 1943): A very controversial possible subspecies from the Tres Marias Islands, Mexico. It appears like a B. c. imperator but has a higher number of ventral scales than B. c. imperator. It is possible a slightly different climate may have caused such a change, but this could then undermine the other insular subspecies such as B. c. orophias and B. c. nebulosa.
- Boa constrictor isthmica (Garman 1883): Considered synonymous with B. c. imperator. It is from Panama.
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