Hello,
I am by no mean an expert on the species, but these are some of the things I have found or heard about. I hope it helps a little. First, I am sorry but I do not know if there are differences in scalation count numbers, but I would be interested to find out. I would suspect there is, as that is often a requirement when determining species classification. There does seem to be some definite differences between the two species in addition to the ones you have pointed out.
First the boa madagascariensis or the Madagascar ground boa reaches a larger adult size than Dumeril’s boa (boa dumerili). Why there are exceptions with both breeds the Madagascar Ground Boa typically reaches an adult size of eight to 10 feet while the Dumeril’s boa generally attains a smaller adult length at six to seven feet. However, I know of several breeders who have dumeril’s that have reached larger adult sizes. In addition, the Madagascar ground boa has fewer offspring. Ground boas typically produce fewer than 10 offspring while dumeril’s have been known to have over 20 offspring. However, I don’t know of many dumeril’s that have had that many babies, but again my experience is limited. My dumeril’s haven’t produced more than 15 offspring at one time. Finally, there seems to be a difference in the rostral scale of the snakes. The dumeril’s rostral scale is more heavily keeled while the ground boa’s rostral scale is more rounded.
The two species will and have been breed in captivity. There are also some people who feel that the two boas may also hybridize in the wild. Dumeril’s range is said to be in the south and southeast portions of Madagascar while the ground boa range is in the north and east. Some feel these ranges may overlap in specific areas. Breeding between the species could explain larger sizes of dumerils taken from northern parts of their range as compared to southern portions. However, environmental factors like temperatures and prey availability could also explain a difference in size. I would like to explain that I am not sure if anyone has done conclusive studies on these issues, these are just some of the things I have heard or read.
Finally, it is true that some dumeril’s were illegally exported into this country. It may be difficult to obtain accurate locality information from these specimens and this could make accurate classifications difficult. In addition, the dumeril’s boa is said to be one of the most interbred boas in captivity. However, that said there are a fair number of breeder in the U.S. who have detailed genetic history of their breeding pairs. Boas were legally exported from European countries and gave some U.S. lines needed diversity. In addition, some breeders are also working with U.S. zoo stock that can be reliably traced to F1 stock. Thus, I think it is fair to say that many breeders can accurately say their offspring are the dumeril’s boa as opposed to the Madagascar ground boa. I do not know as much about the importation history of the Madagascar Ground Boa but it may be similar to that of the Dumeril’s Boa.
I hope this information helps and please respond with any additional questions.
