Dendrophidion percarinatum (COPE, 1893)
Can you confirm these amateur observations of Dendrophidion percarinatum?
|Higher Taxa||Colubridae, Colubrinae, Colubroidea, Caenophidia, Alethinophidia, Serpentes, Squamata (snakes)|
|Common Names||E: South American Forest Racer|
G: Gekielte Waldnatter
|Synonym||Drymobius percarinatus COPE 1893: 344|
Drymobius dendrophis — BOULENGER 1894: 16 (part)
Cacocalyx percarinatus — COPE ‘‘1894’’ (1895): 427
Drymobius dendrophis — GÜNTHER 1885–1902: 127 (? part)
Drymobius dendrophis — AMARAL ‘‘1929’’ : 154 (part)
Dendrophidion percarinatus — SMITH 1941: 73
Dendrophidion percarinatus — PETERS & OREJAS-MIRANDA 1970: 80
Dendrophidion percarinatum — VILLA et al. 1988
Dendrophidion percarinatum — SAVAGE 2002
Dendrophidium percarinatum — SANTOS-BARRERA et al. 2008
Dendrophidion percarinatus — RIVAS et al. 2012
Dendrophidion percarinatum — WALLACH et al. 2014: 225
Dendrophidion percarinatum — CURLIS et al. 2020
|Distribution||N Honduras (Atlántida Province; McCranie, 2011), Nicaragua, N Colombia, NW Venezuela (Rojas-Runjaic and Rivero, 2008), W Colombia (Chocoan region), pacific versant in Costa Rica, Panama, and Colombia; Honduras (McCranie 2011: 109), Costa Rica (Savage (2002: 657). (Lieb 1996, revised map in Figure 9 in Cadle 2012).|
Elevation usually <1,000 m elevation but up to 1,200 m in SW Costa Rica. In Honduras <685 m (McCranie, 2011: 110). other records: 930 m (Panama), 520 m (Nicaragua), and 200 m (Colombia) [Cadle 2012].
Type locality: Boruca and Buenos Aires, Costa Rica.
|Types||Lectotype: AMNH 17366 (designated by Taylor 1954: 727)|
|Diagnosis||Diagnosis. Dendrophidion percarinatum is characterized by (1) dorsocaudal reduc- tion from 8 to 6 occurring anterior to subcaudal 27 (range, 5–26 ); (2) divided anal plate; (3) subcaudal counts .130 in males and females; (4) subadults with narrow pale bands or transverse rows of ocelli (<1 dorsal row wide throughout the body) separated by fewer than three dorsal rows on the neck (bands retained or become obscure in adults, often heavily invested with dark pigment); total number of pale bands on the body >70 (range, 71–96); (5) ventrals immaculate except for lateral dark blotches or mottling; (6) in life, dorsal coloration various shades of brown or gray and usually including dark-bordered pale crossbands anteriorly (sometimes indistinct) and dark brown or blackish stripes posteri- orly (often a broader pair of paravertebral stripes and a narrow lateral stripe on dorsal rows 2 and/or 3); venter without extensive dark spots or transverse lines (scattered small spots may be present), and (7) everted hemipenis of the ‘‘robust’’ morphology, with a relatively short, narrow hemipenial body proximal to a bulbous region bearing spines, calyces, and other apical ornamentation (retracted hemipenis usually extending to between subcaudals 6 to 9, rarely reaching subcaudal 10); total number of enlarged spines on hemipenis <45 (range, 26–40).|
Dendrophidion percarinatum differs from species of the D. dendrophis species group (D. dendrophis, D. atlantica, D. nuchale auctorum, D. apharocybe, D. crybelum, D. vinitor) in having a more proximal reduction in the dorsocaudal scales (nearly always >30 in the D. dendrophis group). A high number of subcaudals and divided anal plate will distinguish it from D. apharocybe, D. crybelum, and D. vinitor (<130 sub- caudals and anal plate nearly always single in these species). Dendrophidion dendrophis, D. atlantica, and D. nuchale auctorum have different color patterns (often with extensive dark ventral spots and flecks; see Duellman, 1978: 236–237, 2005: pl. 175; Savage, 2002: 654–655, fig. 11.39c, pls. 413– 415), attain greater sizes than D. percar- inatum, and have several enormously en- larged hemipenial spines (not so enlarged in D. percarinatum). Dendrophidion percari- natum differs from D. boshelli in having 17 midbody scale rows (15 in D. boshelli).
Dendrophidion percarinatum differs from D. paucicarinatum in having pale dorsal crossbands (variably distinct), often has dark longitudinal stripes on the poste- rior body, and has an immaculate venter. Dendrophidion paucicarinatum usually has a more uniformly colored dorsum lacking distinct pale crossbands, has narrow dark lines across the venter in adults and many juveniles, and has a higher number of ventrals (>175) than D. percarinatum (nearly always <170 except occasional individuals from Panama and Colombia; see discussion of geographic variation). Dendrophidion paucicarinatum may have either a single or divided anal plate.
Dendrophidion bivittatum differs from D. percarinatum in having a color pattern consisting of prominent blackish dorsal stripes on the posterior body and a greenish dorsal ground color. Dendrophidion bivitta- tum also has a shorter tail and fewer subcaudals (<60% of SVL and usually <130, respectively) than D. percarinatum. Dendrophidion brunneum has a greenish to brownish dorsum generally without pale crossbands in adults (often with dark stripes or paravertebral punctations and often with dark transverse lines and other markings on the venter). Dendrophidion percarinatum differs from the two new species described herein (D. prolixum and D. graciliverpa) in having a ‘‘robust’’ hemipenial morphotype as char- acterized herein (‘‘gracile’’ in the last two species). Dendrophidion percarinatum also differs from these species in coloration. Dendrophidion prolixum and D. graciliverpa are green on the anterior body (sometimes restricted to the head) and often have narrow dark transverse lines on the anterior edges of ventral scutes, especially on posterior body. Additional differentiating characters and comparisons are given in the diagnoses for the new species.
|Comment||Relative abundance in Honduras: infrequent|
Habitat: terrestrial, semi-arboreal (Harrington et al. 2018).
Sympatry: Dendrophidion percarinatum is sympatric with several other species of Dendro- phidion within its range. The range of D. percarinatum overlaps with D. apharocybe and/or D. nuchale auctorum from Hon- duras to Panama, and all three occur together at some localities (e.g., La Selva Biological Station, Costa Rica). At the Las Cruces Biological Station in southwestern Costa Rica D. percarinatum is sympatric with three other species—D. crybelum, D. nuchale auctorum, and D. paucicarinatum—yielding perhaps the highest species density of Dendrophidion anywhere. In western Colombia the distributions of D. percarinatum, D. prolixum, and D. nuchale auctorum overlap broadly, with two of the three documented sympatrically at several localities; it would be unsurprising to find the three species occurring together.