Berthold). However, in 1954 E. H. Taylor described one specimen fromthe area as a new subspecies, B. schlegelii supraciliaris. Wermanreturned supraciliaris to synonymy with schlegelii four decadeslater. However, morphometric and color pattern in a SW Costa Ricapopulation (25 specimens) differ from those of specimens (N=57) fromother parts of Costa Rica and from descriptions a South Americanspecimens. Here the epithet Bothriechis schlegelii supraciliarisTaylor 1954, is reestablished as a valid taxon and elevated tospecific rank as B. supraciliaris stat.nov. It is closely related toB. schlegelii from which it differs by its color patterns based on auniform ground color with polymorphic dorsal designs and its lowercounts of ventral and caudal scales.]]>
Abstract
The populations of pit vipers from South West CostaRica, have traditionally been identified as Bothriechis schlegelii(Berthold). However, in 1954 E. H. Taylor described one specimen fromthe area as a new subspecies, B. schlegelii supraciliaris. Wermanreturned supraciliaris to synonymy with schlegelii four decadeslater. However, morphometric and color pattern in a SW Costa Ricapopulation (25 specimens) differ from those of specimens (N=57) fromother parts of Costa Rica and from descriptions a South Americanspecimens. Here the epithet Bothriechis schlegelii supraciliarisTaylor 1954, is reestablished as a valid taxon and elevated tospecific rank as B. supraciliaris stat.nov. It is closely related toB. schlegelii from which it differs by its color patterns based on auniform ground color with polymorphic dorsal designs and its lowercounts of ventral and caudal scales.
Key words
Bothriechis, Viperidae, Serpentes, pitvipers, neotropical, Costa Rica, Pleistocene refugia, taxonomy.
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Wilson & Meyer (1982,1985) examined Taylor's type and againbased on that single specimen, considered it as a slightly aberrantform of B. schlegelii. However, a series of specimens collected inthe mid-elevations of Coto Brus, increased the sample size to 26 andshowed remarkable deviations from the typical schlegelii patterns ofcoloration and prompted a review. Based on coloration and scalecounts we propose that Taylor's taxon is a discrete entity and shouldbe accorded specific rank.
Materials and Methods
Fifty-seven specimens of typical Bothriechis schlegelii (sensulato), from various parts of Costa Rica and twenty-five specimenscollected in the forest reserve of the Las Cruces Biological Station,Coto Brus, Puntarenas, at 1000-1400 m a.s.l., were compared (numbersand localities in Appendix 1) for scale counts and for color patternsof live specimens.
Results
Scale counts: Coto Brus specimens (Table 1 and Fig. 4): dorsalrows 21-23; supralabials 7-11; infralabials 10-12; interoculars 6-9;preoculars 2-4; postoculars 2-4; 1 elongated subocular; 1-2 (rarely3) scales between subocular and supralabials; anal scale entire.Dorsal scales keeled, except for paraventrals. Dorsocaudals keeled.
Ventral and caudal scale counts in Bothriechis schlegelii and B.supraciliaris. Mean in bold to facilitate comparisons.
B. schlegelii B. supraciliaris
Mean S.D. Range N Mean S.D. Range N
Ventrals Males 160.1 2.44 153-167 9 147.3 2.22 145-150 4
Females 156.8 4.75 146-167 48 143.9 2.13 141-148 14
Caudals Males 56.8 2.44 53-61 9 50.2 2.63 48-54 4
Females 51.6 4.34 33-61 43 47.3 2.06 45-52 14
S.D. Standard Deviation. Range (Minimum-Maximum). N Sample size. ]]>
Color pattern: Specimens from Coto Brus have consecutive,well-defined blotches of variable shapes (circular, rhomboidal,disjunct circles and bands, transverse banding) along center ofdorsum, ranging from coffee brown or dark green to rusty brown orreddish maroon. These patterns visibly differ from the rather diffusecoloration of all specimens known from elsewhere in Costa Rica (Figs.1-3). Additionally, the ground color of the Coto Brus specimens,albeit highly variable in hues and shades, is almost always uniformand lacks secondary pigments, while the dorsal ground coloration ofspecimens from elsewhere in the country is highlighted by a varietyof dots, spots or bars of secondary pigmentation (Figs. 1 and 3).Furthermore, the "oropel" morph of typical B. schlegelii, yellowishto golden orange, so well known from other Costa Rican sites isextremely rare in the General-Coto Brus area, where only one specimen(immature male) was seen in ten years of observations by one of theauthors (L.D.G.).
Lepidosis: Specimens from Coto Brus and those from elsewhere inCosta Rica differ in number of ventral and caudal scales (Fig. 4).There are no significant differences in length and number of dorsalscales (Fig. 4).
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Based on these results, we conclude that Bothriechis supraciliariswarrants specific recognition and it is here redescribed:
Bothriechis supraciliaris (Taylor 1954), Fig. 1.
Diagnosis: Closely related to B. schlegelii from which it differsby its color patterns based on a uniform ground color withpolymorphic, dorsal designs and its lower counts of ventral andcaudal scales.
Description: Pitviper of small to moderate size (maximum 600 mm),prehensile tail and strongly triangular outline of head and, fromTaylor's original description: "Front of snout rounding, covered byabout 70 strongly keeled scales anterior to level of thesupraoculars; rostral approximately as wide as high, not visibleabove; on canthus a tiny median scale above rostral; each undividednasal bordered above by three scales with free outer edges; lorealseparated from the upper preocular by one small scale; these threescales bordered above by five scales, three of which have the keelsstrongly elevated into soft, flattened "spines" and forming a linewith the two elevated supraorbital spines; the supraoculars divided,each bearing one or two small, spine-like outer projections;supraoculars separated from the eyes by a row of ten small granularscales; the next row consists of about five scales, two of which arethe elevated supraorbital spines, this row separated from orbit byeight or nine small granules, two or three small postoculars; a longnarrow subocular runs under orbit to or very close to the lowerpreocular; three preoculars, the median and lower border pit; secondlabial separated from lower preocular by small scale, broadlyentering pit and with a scale bordering it above forms the anteriorborder of pit; the second labial has no partial suture entering fromits anterior edge; three to five small lower loreals (prefoveals);9-10 supralabials, the first continuously bordering the nasal; thethird, fourth, and sixth separated from the subocular by three scalerows; infralabials 12-12, only two of which touch the firstchinshields; first pair of chinshields much larger than the threefollowing pairs, but distinctly smaller but perhaps a little widerthan the first pair of labials; temporal scales keeled strongly, thekeels compressed and elevated; about 56 scales across head at angleof jaw; no scales between nasal and rostral. Scale formula: 25, 23,23, 23, 19, 19; ventrals (counting from first widened scale), 146,caudals 46, anal single; the terminal scute of tail rather large; thetail a tip with six rows of scales; 15 in the postanal region; allscales except outer row, and scales on underside of head, keeled."
Our scale counts of the holotype agree with Taylor's, except thatthe caudals are 47. There is a marked sexual dimorphism: the femalesare longer and thicker (pers. observ. of 14 females and 4 males) asin B. schlegelii.
Natural history: B. supraciliaris may tend to spend more time onthe ground than other palm or eyelash pitvipers: 22 out of 25 werefound on the forest floor. The stomach contents of four dissectedspecimens consisted mostly of small rodents of the forest floor. B.schlegelii hunts more arboreal prey such as anoles, hummingbirds andsmall bats.
Specimens collected in resting positions were found curled in aloose circle and mostly on horizontal, wide surfaces, while typicalschlegelii often droop and loop on forks of stems and branches orform a tight S-shaped pattern on almost vertical, rough-barked treetrunks. ]]>
The following specimens are proposed as neoparatypes, deposited atMuseo de Zoología, Universidad de Costa Rica (UCR) andCollection of Vertebrates, University of Texas at Arlington (UTA):Alturas del Río Cotón, Coto Brus, Puntarenas Prov.,1500 m UCR-12082; Estación Biológica Las Cruces, CotoBrus, 1000-1400 m, Puntarenas Prov. UCR- 10641, 12075-12081,13500-13502, 2276, 2277. UTAR-35192, 35193, 35194, 35246.Discussion
Among neotropical pitvipers Bothriechis schlegelii is knownparticularly for its impressive color variation throughout itsgeographical range (Werman 1984, Campbell & Lamar 1989). Itsusual habitat is lowland rainforests although it is also known frommoderate to high elevations (Campbell & Lamar 1989, Crother etal. 1992). In Costa Rica B. schlegelii is amply distributed in theCaribbean and southern Pacific lowlands, but the Pacific range isgeographicaly isolated from the rest of the country(Crother et al.1992).
Recently the systematics of the genera Bothrops and Bothriechishas been the subject of diverse morphological and biochemical studies(Campbell & Lamar 1989, 1992, Shätti et al. 1990,Shätti & Kramer 1991, Cadle 1992, Crother et al. 1992,Werman 1992, Kuch and Freire 1995, Wüster and McCarthy 1996).Taylor's (1954) keen observation of a single specimen (Type, KU.31997) was notable and gross differences shown by the material athand were correct, although the main parameters used for hisdescription were not, as he based the distinction on the aspect andmorphology of some scales that often are ontogenetically variablewithin the species, such as the divided supraoculars and the color ofthe tail tip.
This study shows that, despite normal variation, specimens fromCoto Brus display a notable and constant coloration divergence fromthe rest of the country.
Coloration of the Costa Rican taxon is equally and stronglyrelated to some morphotypes from Colombia and Ecuador as describedand illustrated in Campbell & Lamar (1989). The close resemblanceand affinity of the SW Costa Rican Pacific versant supraciliaris tothe NW South American schlegelii seems to support the hypothesis ofan ancestral continuum of a schlegelii stock, a hypothesis furtherenhanced by the existence of other cases (Solórzano 1995),such as Porthidium volcanicum Solórzano and its vicar P.lansbergii, or by Lachesis muta melanocephala Solórzano &Cerdas (1986) whose color pattern and scaling is closer to the SouthAmerican L. muta muta than to L. muta stenophrys from the Atlanticversant of Costa Rica. In contrast, Zamudio and Greene (1997) defenda greater affinity between this and Stenophrys.
Unlike Werman (1984), we used a larger sample that has evidencedsignificant differences in the number of ventral and caudal scales.Allozyme comparisons of five individuals from Coto Brus, one fromUpala in NE Costa Rica, and one from Ciudad Neily, 35 km SW of CotoBrus, support the differentiation (Crother, unpublished).
The geographical range of supraciliaris seems to be confined tomid and higher elevations (800-1700 m) (Appendix 1). For schlegelii,the range is ampler but mostly confined to lowland rainforestsoutside and within SW Costa Rica. To date, we have found no overlapof the ranges of the two taxa. There is a closer similarity insquamation between Costa Rican supraciliaris and Colombian schlegelii(see Renjifo 1979 for summary statistics of Colombian populations).
The species redescribed here is thus far only known from the Valledel General and the Coto Brus altiplano in SW Costa Rica, and itsexistence suggests that an exhaustive revision of the systematics of Bothriechis schlegelii throughout its range, from NorthernPerú to Mexico, would likely reveal similarly isolated anddiscrete genotypes. ]]>
Resumen
Las poblaciones de toboba de pestañas o bocaracá delsuroeste de Costa Rica han sido denominadas tradicionalmenteBothriechis schlegelii supraciliaris Taylor 1954. Sin embargo, lamorfometría y el patrón de coloración sugierenque es una especie aparte, que aquí se propone comoBothriechis supraciliaris stat.nov.
Aknowledgements
We are grateful to William W. Lamar, Mahmoud Sasa, José M.Gutiérrez and two anonymous reviewers for suggestions togreatly improve this manuscript, and to Alberto León S. forhis drawings. Michael and Patricia Fogden supplied some photographs.The Organization for Tropical Studies, provided logistical supportfor the two senior authors.
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1 Sepentario Nacional, Ave. 1, c. 9/11, San José, CostaRica and Instituto Clodomiro Picado, Universidad de Costa Rica, 2060San José, Costa Rica.
2 Jardín Wilson, Organización para EstudiosTropicales, Las Cruces, Coto Brus, Costa Rica.
3 Centro de Investigación Académica, UniversidadEstatal a Distancia, Sabanilla M. Oca, San José, Costa Rica.Mailing address: Biología Tropical, Universidad de Costa Rica,2060 San José, Costa Rica. Telefax (506)2075550; julianm@cariari.ucr.ac.cr
4 Dept. Biological Sciences, SE Louisiana University, Hammond, LA, USA.
UCR-Number Collection locality Reference collection, Instituto Clodomiro Picado,
3309 Osa, Puntarenas San José, Costa Rica
2879 Penshurt, Limón
3628 Guápiles, Limón Specimen Collection locality ]]>