Tantilla hendersoni STAFFORD, 2004
Can you confirm these amateur observations of Tantilla hendersoni?
|Higher Taxa||Colubridae, Colubrinae, Colubroidea, Caenophidia, Alethinophidia, Serpentes, Squamata (snakes)|
|Common Names||E: Peten Centipede Snake|
|Synonym||Tantilla hendersoni STAFFORD 2004|
Tantilla hendersoni — WALLACH et al. 2014: 701
Type locality: 0.5 km east of Las Cuevas on trail to Monkey Tail River, Cayo District, elevation 580 m.
|Types||Holotype: BMNH 2002.3|
|Diagnosis||Diagnosis: A species of the T. taeniata group that may be distinguished from all other members of the genus by having (1) a dark gray-brown, almost black ground color; (2) a pale nape band that is complete medially; (3) a middorsal|
stripe confined to the vertebral scale row and extending to the distal portion of the tail; (4) narrow pale lateral stripes occupying adjacent thirds of scale rows 3 and 4 that extend to the tip of the tail; (5) the lower third of the paraventral scale row mostly unpigmented; (6) dark mottling on the lateral edges of the ventrals; and (7) 153 ventrals and 64 subcaudals (excluding terminal spine) in the single known female.
Coloration: In life, the pale middorsal stripe was orange tan, the pale lateral stripes were yellowish white, and the pale nape band was bright yellow, all of these markings contrasting sharply with the blackish brown color of the dorsolateral and ventrolateral areas. The dorsal surface of the head was pale brown anteriorly, grading on the posterior cranial scutes to medium brown, the peripheries of these scales notably darker; the light-colored areas on the side of the head were yellow; the mental, infralabials, and margins of adjacent chinshields were also yellow. Except for the dark mottling on the lateral edges of the ventrals, the venter was pearl white and semi-translucent. The tongue was dark brown at its tip, grading posteriorly to pale reddish brown. The iris of the eye was uniformly black.
Comparisons. Wilson and Meyer (1971) recognized two sections within the taeniata group of Tantilla based on differences between the species in dorsal color pattern, the reticulata section, consisting of Tantilla flavilineata, Tantilla oaxacae, and Tantilla reticulata and the taeniata section (subsequently redefined by Wilson, 1983), to which Tantilla briggsi, Tantilla cuniculator, T. impensa, Tantilla jani, Tantilla johnsoni, Tantilla slavensi, Tantilla striata, T. taeniata, Tantilla tayrae, Tantilla tecta, Tantilla tritaeniata, Tantilla trilineata, Tantilla triseriata, and Tantilla vulcani can be allocated. In having a pale lateral stripe on scale rows 3 and 4, T. hendersoni is associated nominally with the latter section; the pale lateral stripe in T. flavilineata and T. oaxacae is wider, occupying scale row 4 and adjacent portions of rows 3 and 5, whereas in T. reticulata scale row 4 and adjacent portions of rows 3 and 5 are brown. Tantilla flavilineata and T. oaxacae further differ from T. hendersoni in having fewer subcaudals in both sexes (43–52 and 46–52, respectively, vs. 64).
Tantilla hendersoni differs from all other species in the T. taeniata group except T. impensa, T. jani, T. slavensi, and T. tecta in having a narrow pale middorsal stripe confined to the central area of the vertebral scale row. In T. briggsi, T. cuniculator, T. tayrae, and T. vulcani, the pale middorsal stripe is absent, ill-defined posteriorly, or reduced to a series of spots, whereas in the remaining species it is expanded laterally to include all of the vertebral scale row and adjacent portions of the paravertebral rows. The pale lateral stripe in T. impensa, T. jani, T. slavensi, and T. tecta is distinctly bordered above (and in T. jani, T. slavensi, and T. tecta also below) by dark flecking or a narrow, continuous dark line, and in these species the color of the dorsum either side of the middorsal stripe is also somewhat paler. Tantilla jani may be further distinguished from T. hendersoni in having less distinct pale lateral stripes that usually terminate on the posterior section of the body, a nape band that is reduced to a pair of pale spots, a smaller light postorbital marking confined mostly to the fifth supralabial, the first pair of infralabials usually in contact, and fewer segmental counts (females with 143–147 ventrals and 44–47 subcaudals vs. 153 þ 64 in the female holotype of T. hendersoni). Tantilla slavensi further differs from T. hendersoni in having a pale nape band that is interrupted medially (vs. complete) and no more than one dorsal scale in length (vs. two in T. hendersoni), a pale lateral stripe that is indistinct on the tail (vs. evident even at tip of tail), an orange venter in life (vs. pearl white), and 52– 56 subcaudals (vs. 64 in T. hendersoni). In T. tecta, the snout is marked with a pale spot involving the upper portion of the rostral, internasals, and anterior two-thirds of the prefrontals, the mid-dorsal pale stripe is ill-defined posteriorly, and there are fewer ventrals and subcaudals (148 + 54 in the single known female).
Ventral and subcaudal scale counts in T. hendersoni fall directly within the range of T. taeniata, to which the new form also bears resemblance in aspects of proportion and general habitus. As indicated by the ordination pattern in Figure 4, however, it is perhaps most closely related to T. impensa. This species has a comparable number of subcaudals (65–72 in females vs. 64 in the holotype of T. hendersoni), a similarly narrow middorsal stripe that is confined to the central area of the vertebral scale row and extends onto the distal portion of the tail, and a dark ventrolateral field. In T. impensa however, the dark ground color on either side of the middorsal stripe is typically paler than that below the lateral stripe (Fig. 2) and bordered above and below by dark gray-brown, the lateral edges of the ventrals are unpigmented, and females have a higher number of ventrals (164–172 vs. 153 in T. hendersoni). Tantilla impensa is potentially also a larger species, with females attaining total lengths in excess of 720 mm (Campbell, 1998a).
|Comment||Similar species: T. impensa and T. taeniata.|
Synonymy: The specific status of this taxon is in doubt. Stafford et al. (2010: 385) stated that “in light of photographs we recently examined of a second, larger specimen from the same locality (ca. 350 mm) ... we suspect that BMNH 2002.3 probably represents a juvenile T. impensa Campbell (1998), and that differences between these two species (size, color pattern features, and ventral scale numbers) are attributable to a combination of geographic and ontogenetic variation. As and when additional material becomes available, we expect T. hendersoni to be relegated to the synonymy of T. impensa.” (cited in WILSON & MATA-SILVA 2015: 439).
|Etymology||Named after R.W. Henderson, Curator of herpetology at the Milwaukee Public Museum.|