B. c. orophias
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Bull. Mus. Comp. Zool., Harvard Univ., 132 (3); 245-273, December, 1964


No. 3-The Lesser Antillean Representatives of Bothrops and Constrictor



The taxonomy of four Lesser Antillean populations of snakes, two of Bothrops and two of Constrictor, has long been in a state of confusion. This situation is perhaps explicable, as so many similar situations in West Indian herpetology are, because there were until now very few examples of these populations in collections, and there was virtually no record of the animals in life.  I have combined in this paper a revision of the Lesser Antillean populations of the two genera because their zoogeography is quite comparable, while their taxonomy presents two very different patterns of differentiation in island forms.


  The genus Constrictor is also known at present from only two islands in the Lesser Antilles.  It occurs on Saint Lucia, with Bothrops, and on Dominica.  Three specimens in the MCZ were received from the New York Zoological Society; two of these, MCZ 6710-11, have no data; the third (MCZ 6659) was supposedly taken on " St. Kitts.  " All three are typical specimens of the Saint Lucian population.  A single specimen collected by Garman (MCZ 6106) represented the Dominican form.  During 1958 and 1959 I collected extensively in Dominica and sent a number of Constrictor to the Philadelphia Zoological Gardens, as well as to the MCZ; subsequently, some of those sent to Philadelphia died and have been placed in the MCZ.  During 1962 I collected in Saint Lucia and placed seven specimens of the Constrictor from that island in the MCZ.  All MCZ specimens are tabulated (Tables 3 and 4).

The nomenclatural problem in this genus is not, perhaps, less muddled than it was in Bothrops, but it is certainly easier to untangle.  There is only one South American species, and its nominate subspecies, Constrictor constrictor constrictor, is the one closest geographically to the Lesser Antillean forms, occurring both in Trinidad and Tobago.  As opposed to Bothrops atrox, which I cannot effectively define in relation to the other species in the genus (except to define the others, and then merely say that anything not fitting those definitions is a "Bothrops atrox"), c. c. constrictor may be defined for comparative purposes as follows:

  Constrictor constrictor constrictor has a slightly prominent snout and a straight or nearly straight canthus; there are 81 to 95 dorsal scale rows at midbody, 234 to 243 ventrals, and 15 to 22 rather neat, geometric, dark dorsal saddles to the level of the anus; the dorsal ground color is fawn-brown to tan; the venter white to yellow with little dark marking a dark stripe proceeds from the eye directly to the supralabials (subocular stripe), and a second proceeds from the eye anteriorly in the loreal region, then curves down onto the supralabials (loreal stripe) ; both stripes correspond to two dark blotches on the infralabials and chin. (See Figures 4 and 5.)

The oldest available date for a Lesser Antillean form is Boa orophias Linneaus (1758) ; the ventral count given unequivocally assigns the name to the Saint Lucian form since no other member of the genus has 28I ventrals.  Dumeril and Bibron (1844) applied the name diviniloqua to a Saint Lucian specimen; this name was originally proposed by Laurenti (1768).  Therefore, diviniloqua, sensu Dumeril and Bibron, is a junior synonym of orophias; diviniloquus, sensu Laurenti, does not seem to apply to any Lesser Antillean form, though, of the two (the Saint Lucian or the Dominican), it could only have applied to orophias.  No name has ever been proposed for the Dominican form, and the few available specimens have always been considered under orophias.  Stull (1935) combined both Saint Lucian and Dominican forms under orophias and separated this composite from constrictor at the species level.

The analogous zoogeographical situation is clear: in Bothrops and Constrictor there are continental forms which occur also on Trinidad (and, in Constrictor, on Tobago too) there is a population far to the north on Saint Lucia in each case, and a third population even farther north, in the case of Constrictor on Dominica.  The taxonomic situation is sharply different, however: the geographically intermediate Constrictor is, with respect to most characters of diagnostic value, morphologically intermediate as well.  There is feasible evidence, then, in Constrictor, for continuity of evolutionary role which simply does not exist in Bothrops.  I therefore regard the populations of Constrictor as members of a stepped-cline series demonstrating geographic variation in a single species and rank these forms as subspecifically related to each other.  The first population in geographic sequence is the Tet'chien of Saint Lucia:


  Boa orophias Linnaeus, 1758, Syst. Nat., 11: 215.

Boa diviniloqua, Dumeril et Bibron, 1844, Erp. Gen., 6: 515.

Boa diviniloquax, Jan, 1864, Icon. Gen., p. 81, pl. iii.

Boa diviniloqua (part), Boulenger, 1893, Cat. Snakes, Brit. Mus., 1: 118.

Constrictor orophias (part), Stull, 1935, Proc. Boston Soc. Nat. Hist., 40 (8): 405.  Barbour, 1914, Mus. Comp. Zool., 44 (2): 329.

  Type:  A specimen currently in the Museum de Geer with 280 ventrals is taken to be Linnaeus' type, fide Andersson (1899).

  Type locality: None designated; here restricted to Praslin, Saint Lucia.

  Diagnosis.  A Constrictor with a prominent snout and a convex canthus; 65 to 75 dorsal scale rows at midbody, 270 to 288 ventrals, and 27 to 31 distinct, subrectangular, dark dorsal saddles to the level of the anus; dorsal ground color rich brown; venter white with black or grey spotting pronounced; subocular stripe distinct and complete; loreal stripe largely obsolete; dark pigment on chin and infralabials not closely corresponding to the facial stripes.

  Description.  In general habitus this form closely corresponds to C. c. constrictor of Trinidad, Tobago, and part of South America.  The principal differences, aside from squamation, are in the darker dorsal coloration, increase of grey patches on the venter, and the general decomposition of the bold, regular pattern so characteristic of C. c. constrictor.  Figures 4 and 5 show the facial markings, more prominent snout, and dorsal pattern of this form compared with those of C. c. constrictor.

  As compared with C. c. constrictor, orophias shows an increase in the number of dark dorsal saddles, and their greater irregularity contributes to the anastomosis of some of the posterior ones.  There is a decrease in number of dorsal scale rows at midbody; however, there is also an increase in number of ventrals and, with respect to this character, orophias is not intermediate between constrictor and nebulosus subsp. nov. of Dominica.  The character, however, is far from being absolute; merely a higher average number of ventrals is not, I think, sufficient to claim that this form represents a distinct species.  Nevertheless, orophias of Saint Lucia, not nebulosus subsp. nov. of Dominica, has the highest ventral counts in the genus.

  Habits and habitat.  Large adults are readily collected simply because of their stationary habits; a specimen seen a week, two weeks, or even a month previously is usually in the same vicinity and easily relocated when one goes to collect it.  Some, e.g. MCZ 75848, from Praslin, were said to have been using the same den sites for many years. Young specimens are very much more "as you find them"; I collected several while hunting for other things, and most often found young ones in trees -one as high as twelve meters from the ground (MCZ 75845).  The Tet'chien is, at any age, rather lethargic; they hiss a great deal when aroused and will strike savagely, though their accuracy leaves a good deal to be desired.   They never seem to be found in the same places as Bothrops: for example, though I got both at Fond Citron of Grande Anse, the Constrictor was in uncultivated woods, the Bothrops in a coconut grove.  Most estate owners and managers protect the Tet'chien, sometimes even fining workers for killing one; this practice is based on the belief that the Tet'chien destroys rats - which it certainly does - though probably not with anything like the efficiency of the Serpent.  Barbour (1937) claimed that the Tet'chien is "rare" on Saint Lucia; I could find no evidence of this.  I never made any special attempt to find one, but rather collected them only when it was easy and convenient.   The people of Saint Lucia certainly do not regard Constrictor as the least bit rare, though admit that they are not found in the fantastic concentrations that Bothrops often are.   To anyone who has ever seen both a mongoose and a Constrictor - even a young one - the idea that mongooses could exterminate the latter must seem a shade ludicrous.

  Range.  The Tet'chien of Saint Lucia occupies the same region as does Bothrops caribbaeus, almost exactly.  It does occur to higher elevations, however: ca. 350 meters.

  Size.  The largest specimen I collected, a male from Anse-La-Raye, was 2.365 meters (MCZ 75847); a female from Praslin (MCZ 75848) was 2.305 meters.  Both of these are sizable snakes, but not by any means of maximum size: a considerably larger individual remains contentedly at Anse-LA-Raye simply because I had no intention of either attempting to carry it out of the bush or to preserve it even if I got it out.

  Relationships. The differences between this form and C. c. constrictor are absolute with respect to a number of characters (e.g., ventrals, dorsal saddles and loreal stripe).  Were it not for the fact that the Dominican form is likewise absolutely distinct, and even more extreme in the same direction with respect to all characters except ventral count - so rendering orophias intermediate between two extremes of coloration, morphology, and geography - I would regard full species status as necessitated for this form.   As it happens, however, we have a remarkable “stepped-cline” series of which orophias is the middle member of three steps.

  Actually, in terms of color and shape of dorsal markings, orophias and constrictor are quite similar; with respect to squamation and number of dorsal markings, orophias is more similar to the Dominican Tet'chien.  In allusion to the extremely dark, clouded appearance of the latter form I describe it as:


  Boa diviniloqua (part), Dumeril and Bibron, 1844, Erp.   Gen., 6: 515.

Boa diviniloqua (part), Boulenger, 1893, Cat. Snakes, Brit. Mus., 1: 118.

Constrictor orophias (part), Barbouir, 1914, Mem.  Mus. Comp. Zool., 44 (2): 329; Stull, 1935, Proc. Boston Soc. Nat. Hist., 40 (8): 405.

  Type:  MCZ 65493, J. D. Lazell, Jr. coll., 30 July, 1959.

  Type locality: Woodford Hill., Dominica.

  Diagnosis.  A Constrictor with a prominent snout and a strikingly convex canthus; 59 to 69 dorsal scale rows at midbody, 258 to 273 ventrals, and 32 to 35 very obscure, irregular transverse markings to the level of the anus; dorsal ground color very dark, clouded, grey-brown; venter ash to slate grey, blotched and mottled with black; both loreal and subocular stripes absent, or, at most, partially indicated and largely obsolete infralabials and chin merely grey.

  Description of the type.  MCZ 65493 is an adult female with 64 dorsal scale rows at midbody, and 264 ventrals.  The anal is single.  There are 19 supralabials on each side; there are 21 infralabials on the right, 20 on the left.  Preserved, the type measures 1,438 mm, of which 172 mm are tail.

  There are 33 dark transverse markings to the level of the anus; these markings are irregular in shape, not much darker than the dorsal ground color and appear almost more as mottling than actual transverse saddles.  The dorsal ground color, in life, was greyish chocolate-brown.  Posteriorly, the transverse markings become more distinct, black bordered and dark brown; the ground color, contrastingly, becomes yellower brown.  On the tail, therefore, the pattern consists of very dark brown, blackbordered saddles set off by intervals of ochre.

  The venter is ash grey anteriorly and becomes very dark -slate grey to black - posteriorly; there are irregular dark blotches along the lateral edges of the ventrals anteriorly, and these become obliterated posteriorly.  The chin is entirely grey, though paler medially.

  The head has a dark temporal stripe, extending from the eye to beyond the commissure of the mouth, distinctly darker- bordered along its ventral edge.  In life, there was a discernible dark streak down the middle of the head. The face is paler grey, and there was, in life, a pink suffusion below the eye and on the loreal region.  There are no indications of subocular or loreal stripes.

  Paratypes:  MCZ 65494, same data as the type; MCZ 65492, Moore Park, Dominica, J. D. Lazell, Jr. coll., 21 June, 1958; MCZ 65495, Layou Park, Dominica, J. D. Lazell, Jr. coll., 14 August 1959; MCZ 58772, Trafalgar, Dominica, J. D. Lazell, Jr. coll., 18 June, 1958; MCZ 74371, Trafalgar, Dominica, J. D. Lazell, Jr. coll., 18 June, 1959; MCZ 6106, Portsmouth, Dominica, S. Garman coll., 1879.

  Variation.  Variation in dorsal scale rows at midbody, number of ventrals, and number of transverse markings to the level of the anus is tabulated (Table 4).  Supralabials vary from 19 to 21; infralabials vary from 20 to 22.

  The dorsal ground color varies somewhat, MCZ 65493 representing the light extreme (still cloudy grey-brown and with very indistinct markings), and MCZ 65492 representing the darkest individual collected (were MCZ 65492 any darker, I would be forced to call it black).  MCZ 6106, collected in 1879, is pale, but this is due to fading; it is, despite this, typical in markings and shows them rather well. (A portion of a head also collected by Garman on the same trip bears the number MCZ 6107; it is deliberately not designated as a paratype.)

  Habits and habitat.   Barbour's (1937) comment that this form is "less uncommon" than the Tet'chien of Saint Lucia is misleading: I would describe them as being amazingly abundant.  The Dominican Tet'chien, like its relative in Saint Lucia, hisses loudly when aroused and strikes rather blindly.  Too, it is basically lethargic and prone to remaining in the same place for long periods of time.   While staying at Woodford Hill I capitalized on their habitual laziness to save snake sacks, and merely left the snakes where I found them: they were almost always still there when I returned, even after several weeks.   Congregations of three to twelve specimens denning in the same hollow log or tree stump are not at all uncommon, especially along the edges of machine-cleared banana fields where suitable den sites are often in profusion.

  The people of Dominica, unlike most in Saint Lucia, have no Bothrops to fear and thus enjoy being deathly afraid of the Tet'chien; sometimes they even kill them, though usually only when the snakes take to raiding hen houses, which seems to be rare.  Children, once initiated, are not at all afraid of even the biggest ones, however, and their parents are often shamed into changing their minds about the danger of the Tet'chien simply because the children come to regard them as play-toys.   Accidents are rare even so: even when a Tet'chien strikes with potentially dangerous accuracy, it will seldom remember to close its mouth in time to actually bite.

  The Dominican Constrictor, like its relatives, is often encountered in trees (though large adults rarely are).   Apparently they eat rats almost exclusively now, though agoutis (Dasyproctis) are abundant in many parts of the island and are no doubt taken as well.

  Range. Constrictor constrictor nebulosus seems to occur throughout the island, at least to elevations of ca. 350 meters.  It is, however, confined to wet ravines in dry country, e.g. at the south tip around Scott's Head, and may be largely replaced along the very dry northern leeward coast by the "Tet'chien Blanc," Clelia.

  Size.  The largest specimen collected, MCZ 65490-, is a female of 1,847 mm total length; the tail is truncated, being only 87 mm long.  Another female, MCZ 65492, is of more normal proportions, being 1,786 mm total length, of which 203 mm is tail.  As with the Saint Lucian form, however, these specimens are far short of maximum for their taxon.  A specimen owned by Rene’ Honegger of the Zurich Zoo (one of a litter produced in 1958 at the Philadelphia Zoo), is now "three meters" long (pers. comm.). For the sake of practicality, the biggest ones are best left in the bush.

  Relationships.  Constrictor constrictor nebulosus is the terminal form of a stepped-cline series, as discussed under C. c. orophias.  Breeding experiments with other subspecies of Constrictor constrictor would be most interesting in assessing whether or not the subspecific rank I have accorded this form, due to its membership in a stepped-cline series, has merit from the standpoint of reproductive potential, as well as geographical and morphological characteristics.  Such experiments are being contemplated by Honegger (pers. comm.), though the male he intends to use is a specimen of the very different C. c. occidentalis.  It must be noted, however, that these two completely allopatric forms have never been subjected to any selection pressure whatever relative to interbreeding, and therefore the presence or absence of reproductive isolation between them may be entirely happenstance, if they are artificially placed in "sympatry."


  In re-evaluating the taxonomy of Lesser Antillean Bothrops and Constrictor I have, in one case, separated at the species level two forms which had been previously lumped, not only with each other but with their South American relatives; in the other case, I have split one "species" into two forms, both of which I have placed as subspecies of their South American relative.  As these are island forms, I have had no possible recourse to evidence of reproductive isolation or the lack of it.  It would appear also that morphological degree of difference has not been consistently used in my classification.  Thus, Bothrops caribbacus is absolutely different from all other members of its genus only in the characters of ventral pigmentation and dorsal patterncolor characteristics that many consider trivial, no matter how constant and definitive.  Bothrops lawceolatus, though "more different" morphologically, is absolutely distinct ultimately only on the basis of its squamation characters combined with ventral pigmentation, thus falling back once again on a color character.

Constrictor constrictor orophias, however, is more different from any other subspecies of Constrictor constrictor than any of them are from each other (nebulosus excepted) with respect to such a conventionally respectable character as ventral count; this I have nevertheless made a subspecies.  My reasons for ranking these forms as I have center around the concept of the species set forth by Simpson (1961), in which the principal criterion of conspecificity is continuity of evolutionary role.

A subspecies, as I would define it, is a rather peculiar sort of geographical variant within a species that has a wider range; it must be sharply defined (as opposed to gradually clinal) and diagnostically homogeneous (as opposed to the sort of situation which arises from discordant variation).  Nevertheless, subspecies are, from the standpoint of evolutionary role, perfectly continuous with each other within their species.  Continuity of evolutionary role, even between forms that are morphologically very dissimilar in many respects, can be maintained by direct intergradation a d continuous gene flow.  As Simpson (p. -153) points out, however, geographic isolation tends to break the continuity of evolutionary role by actually breaking the continuity of gene flow.

  Therefore, I am willing to admit as geographic races of a single species only those geographically isolated forms in which there is apparent continuity of evolutionary role expressed in the characteristics of the animals.  (In the cases presented, the critical characteristics have been morphological but this is certainly not obligatory.)  In Constrictor there is a sequential increase proceeding northward through the three populations in the following, characters: scale size (= decrease in dorsal scale rows at midbody), number of transverse saddles, darkness of coloration, irregularity of pattern, obliteration of facial markings, and convexity of the canthus.  On the other side of the slate is ventral count; in this case the sequence is broken and the geographically intermediate form has the highest average.   Nevertheless, the balance of characters examined would seem to indicate that there is a continuity of evolutionary role, expressed in the morphology of the populations, proceeding from Constrictor constrictor constrictor through Constrictor constrictor orophias to Constrictor constrictor nebulosus.

  In the case of the Bothrops populations, the geographic conditions are admirably suited for this sort of pattern, but the animals fail completely to conform in all discernible characters.   Their morphological and behavioral characteristics are such that by any standard there can be no doubt that the Antillean forms are distinct species relative to each other.  Assigning one or the other to subspecific rank under one of the South American forms would require an initial arbitrary choice as to which of the Antillean populations should be assigned to a South American form - a subsequent arbitrary choice would then be necessary to determine under which South American form to place the Antillean population chosen.  In the end, we would be faced with the overwhelming reality that we had merged forms merely because they were allopatric.

  Two primary objections to my criteria of continuity may be cited: first, the islands may have been populated in a way which obscures the true relationships of the animals.  That is, had a distant island been the first place a new form differentiated, then a second, intermediate one colonized from that stock, and subsequently differentiated again, in each case the differentiation might have produced what would have been a stepped-cline series, had the geographic sequence been intelligible.  Secondly, it is readily seen that no less than three populations are necessary before we can discern the stepped cline.  That is, if Dominica and its Constrictor did not exist, I would have classified orophias as a full species, since there would have been no evidence for continuity of evolutionary role.

  Both of these arguments are quite valid. It must be pointed out, however, that whenever a geographically and reproductively isolated, absolutely distinct population is classed as a subspecies a special sort of geographical variant within a more wide-spread species), this is an act of presumption. Conservatively speaking, the form qualifies as a species completely. It is only by means of strong evidence to the contrary that we may really refuse to rank it as such.  As any taxonomist ultimately must admit, the relationships of an animal are not affected by our inability to discern them, but what we are able to say about them is.

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