Anilios zonula ELLIS, 2016
Can you confirm these amateur observations of Anilios zonula?
|Higher Taxa||Typhlopidae (Asiatyphlopinae), Typhlopoidea, Serpentes, Squamata (snakes)|
|Common Names||E: West Kimberley Blindsnake|
|Synonym||Anilios zonula ELLIS 2016|
|Distribution||Australia (Storr Island, Augustus Island, Western Australia)|
Type locality: Storr Island, Western Australia, Australia (15°57’8.71’’S, 124°33’49.54’’E; datum = WGS84.
|Types||Holotype: WAM R171667 (Fig. 1), adult female, collected on 20 May 2009 by V. Kessner. Fixed in 10% formalin, stored in 70% ethanol at WAM. Paratype: WAM R106250, subadult female collected from Augustus Island, Western Australia, Australia (15816012.0000S, 124833028.8000E), on 12 July 1990 by A. Sanders. Fixed in 10% formalin, stored in 70% ethanol at WAM.|
|Diagnosis||Diagnosis. A moderately slender and elongate Anilios, total length to 187 mm. Distinguished from all other congeners by a combination of midbody scales in 18 rows, total dorsal scales 446–482, dorsal body scales 431–471; snout bluntly rounded in dorsal and profile view (Fig. 2); rostral scale large and ovate about one-half of head width, with posterior edge terminating anterior to level of eyes; nasal scale divided, nostril positioned closer to rostral than preocular, distance between nostril and rostral about one- half of nostril width; nasal cleft originating from second supralabial, extending dorsally and anteriorly to reach nostril and thence anteriorly to reach rostral; eye inconspicuous, equal to or slightly smaller than width of nostril, positioned under preocular scale; tail tip bluntly rounded, terminal tail spine absent; coloration purplish–pink to pale pink, darkest anteriorly, gradually becoming lighter posteriorly.|
Coloration. In life (Fig. 1A in Ellis 2016), patternless, purplish–pink to pale pink, darkest anteriorly, gradually becoming lighter posteriorly; tail pale pink; snout and lower jaw to level of eyes pink, much lighter than crown and remainder of head to anterior body. In preservative (Fig. 1B,C), anterior half of body darker than posterior half, anterior half light cream to pale pink, snout slightly lighter, posterior half (including tail) pale cream to tan. Coloration uniform on dorsal, lateral, and ventral surfaces, no darker pigmentation on scales; eyes dark but inconspicuous.
Variation. Only one additional specimen is available, the paratype (WAM R106250). The morphology of the paratype is consistent with the holotype; however, where variation occurs, the data are presented below for the paratype. Measurements and counts: SVL 154 mm; TailL 3.1 mm, 2.0% of SVL; MBW 2.4 mm; TDS 482; BDS 471; MBSR 18; SCS 11. Frontal approximately 1.25 times larger than postfrontal in area. Interparietal approximately 1.5 times the size of postfrontal. Parietals slightly narrower than supraoculars, widely separated by interparietal. Nasals narrowly separated by frontal, separation about one-fifth of frontal width. Eyes positioned in apex of preocular scale.
Sexual dimorphism: unknown, as both known specimens are female.
Comparison. Anilios zonula differs from 34 of the other 44 Anilios species in Australia by the number of MBSR (18 vs. 16, 20, 22, or 24), which, with the exception of A. leptosoma (16 or 18 MBSR), does not vary within any species of Anilios. It is further distinguishable from all remaining congeners except A. aspina by the lack of a terminal tail spine. Anilios zonula differs from A. aspina by having nasal divided, nasal cleft extending anteriorly to reach rostral from nostril and not visible in dorsal view (vs. extending dorsally, not reaching rostral and visible in dorsal view).
Of the 10 congeners with 18 MBSR, A. zonula can be diagnosed by a combination of the following characteristics: DBS 446–482 (vs. .500 in A. grypus, A. guentheri, and A. leptosoma); snout bluntly rounded in dorsal view (vs. weakly trilobed in A. grypus, A. leptosoma, and A. margaretae) and bluntly rounded in profile view (vs. bluntly angular in A. affinis and A. margaretae, or beak-like and hooked in A. grypus); rostral scale ovate and not truncating anteriorly (vs. rostral ovate, truncating anteriorly in A. micromma, A. leptosoma, and A. grypus); nasal scale divided (vs. not completely dividing nasal in A. aspina, A chamodracaena, A. guentheri, and A. margaretae); eye equal to or smaller than width of nostril (vs. equal to or larger in A. affinis, A. aspina, A. grypus, A. guentheri, A. howi, A. margaretae, and A. yampiensis); nostril positioned closer to rostral than preocular, nasal cleft originating from second supralabial (vs. preocular in A. yampiensis) extending dorsally and anteriorly to reach nostril, then anteriorly to reach rostral; tail tip blunt and rounded, lacking terminal tail spine (vs. terminal tail spine present in A. affinis, A. chamodracaena, A. grypus, A. guentheri, A. howi, A. leptosoma, A. margaretae, A. micromma, and A. yampiensis); coloration darkest anteriorly, gradually becoming lighter posteriorly, and tail and/or head lacking any black pigmentation (vs. black pigment present on head and/or tail in A. grypus and A. guentheri).
Of the 10 Anilios species known to occur in the Kimberley region of Western Australia, A. zonula can be diagnosed from five (A. diversus, A. kimberleyensis, A. ligatus, A. troglodytes, and A. ungirostris) by having midbody scales in 18 rows (vs. 16, 20, 22, or 24). Of the five species in the region with 18 MBSR, A. zonula differs from A. grypus in the lack of any dark brown or black pigment on the head or tail, lack of a hooked beak, and fewer DBS (,500 vs. .500). It differs from A. guentheri by the absence of any dark brown or black pigment on its head and tail and lack of terminal tail spine, fewer DBS (,500 vs. .500), and nasal cleft completely dividing nasal scale. It is further diagnosed from A. howi by the lack of dark brown or black pigmentation on the head or tail, eye equal to or smaller than width of nostril (vs. equal to or larger than width of nostril), path of nasal cleft from nostril, extending anteriorly to reach rostral scale (vs. cleft curving dorsally and anteriorly towards rostral), and lack of terminal tail spine.
Within the Kimberley region of Western Australia, Anilios zonula is most similar to A. micromma and A. yampiensis. From A. micromma, the new species differs by the position of the nostril, positioned closer to rostral than preocular; distance from rostral approximately equal to width of nostril (vs. equidistant or closer to rostral but distance more than the width of nostril); path of nasal cleft, from nostril extending anteriorly to reach the rostral, and not visible in dorsal view (vs. extending dorsally and anteriorly, and visible from above in A. micromma); the lack of a terminal tail spine; and the size and shape of rostral scale, about one-half of head width at level of eyes (vs. about one-third of head width), not truncating anteriorly (vs. truncating anteriorly) with posterior edge not reaching the level of the eyes (vs. at level of eyes). From A. yampiensis, the new species differs by the origin of nasal cleft from second supralabial (vs. preocular); small eye, approximately equal to or smaller than width of nostril (vs. eye greater than width of nostril); lack of terminal tail spine; and rostral about one-half the width of head (vs. about one-third width of head) with posterior edge not reaching level of eyes (vs. at level of eyes).
|Comment||Habitat: Both specimens were collected from under sandstone rocks. R171667 was collected from a rocky slope in a vine thicket (Ellis 2016: 276).|
|Etymology||The specific epithet is from the Latin word zo ̄nula meaning ‘‘little belt,’’ in reference to the narrow and slender appearance of the species. Used as a noun in apposition.|