Rhadinella xerophila ARIANO-SÁNCHEZ & CAMPBELL, 2018
Can you confirm these amateur observations of Rhadinella xerophila?
|Higher Taxa||Colubridae (Dipsadinae), Colubroidea, Caenophidia, Alethinophidia, Serpentes, Squamata (snakes)|
|Synonym||Rhadinella xerophila ARIANO-SÁNCHEZ & CAMPBELL 2018|
Type locality: northern limit of Heloderma Natural Reserve (HNR) at El Arenal (14.868878 N, 89.790526 W; 580 m above sea level, asl hereafter), Cabañas, Zacapa, Guatemala
|Types||Holotype. UVG R-7003, adult male, collected on 29 October 2016 by D. Ariano-Sánchez.|
|Diagnosis||Diagnosis. Small, slender and gracile snake of genus Rhadinella, which can be distinguished from the other congeners by the following unique combination of characters: head only slightly distinct from neck; inverted dark U-shaped marking on rostral; anterior supralabials with dark edges and pale centers; conspicuous orange collar on neck divided at mid-dorsum, extending 3.5 scale lengths at mid-dorsum and three scale lengths on side of head, posterior to ultimate supralabial; no subpreocular scale; no broad diastema; temporals 1 + 2; dorsal scale rows 17, smooth, unreduced throughout body; ventrals 158; cloacal scute divided; tail complete, subcaudals 116, divided; dorsal coloration dark gray to blackish, almost totally obfuscating longitudinal striping, ground color not extending to lateral edges of ventrals.|
Rhadinella xerophila differs from R. godmani, R. hannsteini (Stuart 1949), R. hempsteadae, R. kanalchutchan (Mendelson & Kizrian 1995), R. kinkelini, R. lachrymans (Cope 1970), R. montecristi (Mertens 1952), R. pegosalyta (McCranie 2006), R. rogerromani (Köhler & McCranie 1999), R. serperaster (Cope 1871) and R. tolpanorum (Holm & Cruz 1994) by having a dark gray dorsal body coloration and absence of conspicuous striping (vs. conspicuous striping and lighter brown color dorsal body coloration). Additionally, the new species differs from R. godmani, R. hempsteadae, R. kanalchutchan, R. montecristi, R. pegosalyta, and R. serperaster by having 17 dorsal scale rows (vs. > 17 dorsal scale rows). Rhadinella xerophila can be most easily confused with R. donaji (Campbell 2015), R. dysmica (Campillo, Dávila-Galavíz, Flores-Villela & Campbell 2016), R. schistosa (Smith 1941), R. pilonaorum, and R. posadasi (Slevin 1936), all of which have almost uniformly dark brown or black dorsum, pale dashes on most dorsal scales, and often an indistinct dark vertebral line. Rhadinella xerophila has a mostly dark head with broad orange edging on supracephalic scales differing from R. donaji with a mostly white head, R. dysmica, R. posadasi, and R. schistosa with mostly or uniformly black heads, and R. pilonaorum with top of head mostly orange with black mottling; differing from R. donaji and R. dysmica by having fourth and fifth infralabials contacting posterior genials (vs. third and fourth); differing from R. donaji, R. dysmica, R. pilonaorum and R. posadasi by having 1+1 temporals (vs. 1 + 2); segmental count differences difficult to evaluate owing to paucity of material, but R. xerophila appears to have more ventrals in males, 158, than do R. schistosa (145–147), R. posadasi (136–141), and R. pilonaorum (151–153), and less than R. donaji (158 vs. 166); number of subcaudals in R. xerophila exceeds the number known for all other dark Rhadinella (Table 1).
|Comment||Habitat: The holotype was found active crawling on sandy soil in a dry gully at approximately 19:30 h. The landscape is composed of patches of seasonally dry tropical forest and tropical thorn scrub, within a matrix of cornfields and melon crops. Most of the topography is undulating, with steep slopes (Fig. 1B). The vegetation includes such distinctive dry forest species as Bursera excelsa (Burseraceae), Nopalea guatemalensis (Cactaceae), Pilosocereus leucocephalus (Cactaceae), Stenocereus pruinosus (Cactaceae), Leucaena collinsii (Mimosaceae), Lysiloma divaricatum (Mimosaceae), Bucida macrostachya (Combretaceae), and Bonellia macrocarpa (Theophrastaceae).|
Sympatry: Ctenosaura palearis (Stejneger 1899) and Heloderma charlesbogerti (Campbell & Vannini 1988).
Distribution: see map in ARIANO-SÁNCHEZ & CAMPBELL 2018: 342 (Fig. 3).
|Etymology||The specific name is a feminine noun in apposition from the Greek ξηρός (xeros), meaning dry and the Latin phila, meaning loving, in reference to its characteristic of being the sole known member of Rhadinella that inhabits in forest experiencing the harsh and extended dry season characterizing the Motagua Valley. It also represents the urgent need that people and governments take the dry forest seriously as a biodiversity relevant forest that deserves the same levels of protection and love as other more known and charismatic forests such as rainforest.|