Dendrophidion nuchale (PETERS, 1863)
Can you confirm these amateur observations of Dendrophidion nuchale?
|Higher Taxa||Colubridae, Colubrinae, Colubroidea, Caenophidia, Alethinophidia, Serpentes, Squamata (snakes)|
|Common Names||E: Peters' Forest Racer|
S: Culebra terrestre
|Synonym||Herpetodryas nuchalis PETERS 1863: 285|
Dendrophidion clarkii DUNN 1933: 78 (fide LIEB 1988)
Dendrophidion dendrophis — ROZE 1952: 99
Dendrophidion vinitor — WILSON 1966
Drymobius percarinatus — LANCINI 1979
Dendrophidion dendrophis — PETERS & OREJAS-MIRANDA 1970: 80
Dendrophidion nuchalis — BAUER et al. 1995: 72
Dendrophidion nuchale — KORNACKER 1999
Dendrophidion nuchale — ESQUEDA et al. 2001
Dendrophidion nuchale — WILSON & MCCRANIE 2002
Dendrophidion nuchalis — CARRERA et al. 2009
Dendrophidion clarkii — MCCRANIE 2011
Dendrophidion nuchale — WALLACH et al. 2014: 225
|Distribution||N Venezuela (coastal cordillera, Zulia, Carabobo, Guárico, Miranda, Yaracuy); elevation: <100-1270 m (see comment).|
Type locality: “Caracas” [Venezuela]
|Types||Syntypes: ZMB (lost)|
Neotype: USNM 129579 (designated by LIEB 1988; invalid fide CADLE 2012)
|Diagnosis||Diagnosis. Dendrophidion nuchale is characterized by (1) dorsocaudal reduction from 8 to 6 occurring posterior to subcaudal 25 (range, 27–54); (2) anal plate single or divided (approximately equal frequencies); (3) subcaudal counts > 135 in males and females; (4) ground color of head and body brown; dark crossbands with embedded pale ocelli present on the posterior half or more of the body and tail (Fig. 1); tail not strongly differentiated in color from posterior body; (5) blackish or dark brown nuchal collar present in adults (evident or not in juveniles); (6) ventral scutes in adults usually with irregular dark anterior borders to each scale (often interrupted midventrally) and sometimes with other irregular dark flecks or spots (Fig. 1); (8) total number of enlarged spines on the hemipenis relatively few (< 60); spines in the distal row uniform in size and numbering < 15 (12–14).|
Apart from Dendrophidion nuchale, no other species of Dendrophidion except the allopatric species D. clarkii has a prominent blackish nuchal collar in adults (less distinct or absent in juveniles). Dendrophidion nuchale differs from species of the D. percarinatum group in having a more distal dorsocaudal reduction (typically proximal to subcaudal 25 in the percarinatum group compared to > 25 in D. nuchale). Single anal plates occur in the D. percarinatum group only in some individuals of D. paucicarinatum. Dendrophidion boshelli has 15 midbody dorsal scale rows (17 in D. nuchale).
Dendrophidion nuchale differs from species of the D. dendrophis group as follows. The three species of the D. vinitor complex (D. vinitor, D. apharocybe, D. crybelum; Cadle 2012a) lack a nuchal collar, have prominent pale bands on the anterior body of adults and fewer subcaudals (< 130) than D. nuchale (> 135). Dendrophidion dendrophis lacks a nuchal collar and has a longer tail (> 70% of SVL in adults) and more subcaudals ( 150) than D. nuchale (< 70% and < 150, respectively). Dendrophidion atlantica lacks a nuchal collar.
Dendrophidion nuchale has previously been confused with the two other members of the nuchale complex, D. clarkii and the new species described herein, D. rufiterminorum, but it is allopatric to both species. Dendrophidion rufiterminorum lacks a nuchal collar and has a reddish head and tail; see its species account for further distinctions and comparisons. Dendrophidion nuchale and D. clarkii both have dark nuchal collars but otherwise differ greatly in coloration. In D. clarkii the head and anterior one third to two thirds of the body are bright green in life (brown in D. nuchale, although with greenish edging to some anterior dorsal scales in some individuals). Dendrophidion nuchale also typically has fewer ventrals and subcaudals than D. clarkii (Table 1).
Juveniles of D. nuchale, D. clarkii, and D. rufiterminorum can be more easily confused than adults because the color characteristics of adults (e.g., dark nuchal collar in the first two species, red head and tail in the last) are less distinct or absent in juveniles. Sympatry among these species occurs between D. clarkii and D. rufiterminorum on the Caribbean versant and uplands of extreme northwestern (Pacific versant) Costa Rica. The head and sometimes the tail of juvenile D. rufiterminorum are usually reddish brown and somewhat paler than the adjacent portions of the body, as shown by photographs of D. rufiterminorum in Savage 2002: pl. 414 and Solórzano 2004: fig. 56 (see Fig. 17 in the species account for D. rufiterminorum). The head and tail of juvenile D. nuchale are not differentiated in color and juveniles of D. clarkii have a bright green head and anterior body. The dorsocaudal reduction of D. rufiterminorum is distal to subcaudal 45 (< 55 in D. nuchale and D. clarkii; Table 1) [from CADLE & SAVAGE 2012].
|Comment||Synonymy partly after PETERS & OREJAS-MIRANDA 1970, VILLA et al. 1988, LIEB 1988, CADLE & SAVAGE 2012. In much of the literature on Venezuelan snakes prior to 1988, Dendrophidion nuchale was referred to by the name “D. percarinatum”.|
Distribution: restricted to N Venezuela fide CADLE & SAVAGE 2012 who split up the species into D. nuchale, D. clarkii, and D. rufiterminorum. Previously the species was considered to be widespread in Central and South America, including Belize, Costa Rica, Nicaragua, Honduras, Panama, Colombia, Ecuador, Venezuela (coastal cordillera, Zulia, Carabobo, Guárico, Miranda, Yaracuy). Most of that range is now assigned to D. clarkii. Symbols for D. nuchale and D. dendrophis are reversed in figure 1 of Natera- Mumaw 2008.
Abundance in Honduras: rare
|Etymology||Nuchale is derived from the Medieval Latin noun nucha, meaning the back of the neck or nape (originally from an Arabic word meaning spinal cord, with transfer of meaning) + the adjectival ending –alis (pertaining to). It presumably is an allusion to the black nape collar of Dendrophidion nuchale. The form “nuchalis” (the masculine and feminine form of the adjective) is often seen in combination with Dendrophidion, but the neuter form nuchale is required in this case to agree with the Greek neuter diminutive ending –ion of the genus name.|