Dipsas cisticeps (BOETTGER, 1885)
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Higher Taxa | Colubridae (Dipsadinae), Colubroidea, Caenophidia, Alethinophidia, Serpentes, Squamata (snakes) |
Subspecies | |
Common Names | E: Neotropical Snail-eater |
Synonym | Leptognathus (Dipsadomorus) [sic] cisticeps BOETTGER 1885: 237 Dipsas cisticeps — BERTONI 1914: 29 Dipsas indica cisticeps — PETERS 1960: 78 Dipsas indica cisticeps — PETERS & OREJAS-MIRANDA 1970: 87 Dipsas bucephala cisticeps — HARVEY & EMBERT 2008: 64 Dipsas cisticeps — CACCIALI et al. 2016 Dipsas cisticeps — ATKINSON et al. 2017 |
Distribution | E Bolivia (Cochabamba, Santa Cruz), NW Argentina, W Paraguay Type locality: Paraguay |
Reproduction | |
Types | Holotype: unlocated, not in SMF (Pier Cacciali and Sebastian Lotzkat, pers. comm., 1 Aug 2017). |
Diagnosis | Diagnosis. The following combination of characters distinguishes Dipsas bucephala from all congeners: (1) dorsals 13, usually without reduction or with reduction to 11 relatively close to vent; (2) temporals excluded from orbit by postoculars; (3) usually two pairs of infralabials in contact behind mental; (4) infralabials broadly contacting second pair of chinshields or sublabials occasionally (22% of the time) separating infralabials and second pair of chinshields; (5) loreal square, entering orbit; (6) preocular present above loreal, excluding prefrontal from orbit; (7) dorsal head scales with few large brown spots edged in yellow; (8) labials immaculate or with scattered black marks not concentrated at dorsal apices of scales or forming regular bars; (9) nuchal collar tan to light gray; first blotch not reaching rictus and separated from parietals by 4–8 vertebrals; (10) dorsum tan to light gray with darker markings narrowly edged first in yellow then in dark brown; body blotches, and often interspaces, with row of subcircular cream to yellow spots, at least anteriorly; (11) dorsal blotches incomplete ventrally; widest at paraventrals, longer than interspaces over most of body; usually not forming bands anteriorly; (12) interspaces mostly immaculate dorsally; large dark brown accessory blotch of paraventral region fusing to varying degrees with body blotches; (13) paraventral pattern extending onto venter, center of venter mostly immaculate or with narrow longitudinal line; (14) ventrals 169–194; (15) subcaudals 77–107; (16) maxillary teeth 14–15 (Harvey & Embert 2008: 64). Variation. Peters (1960a) examined 11 Bolivian specimens that he referred to Dipsas indica cisticeps. Mensural and meristic data for our larger sample of mostly new material expand known ranges for some characters (Table 3–4). Specimens in our sample have 8– 10 supralabials (8 6 1, 36), 11–14 (13 6 1, 33) infralabials, 19–28 (24 6 2, 25) blotches on the body, and 12–19 (15 6 2, 24) blotches on the tail. The first blotch extends for 7–14 (10 6 2, 19) vertebrals and 4–8 (6 6 1, 26) vertebrals separate it from the parietals. Neither ventral (t9,15 5 1.58, P 5 0.13) nor subcaudal (t7,14 5 0.53, P 5 0.60) counts are obviously sexually dimorphic in this species, however we did not investigate the power of our statistical test and the insignificant P value for ventral counts may be due to small sample size. On the other hand, males have relatively longer tails than females (t9,14 5 5.25, P 5 0.00). Males in our sample have 173–194 (182 6 6, 15) ventrals and 81–107 (90 6 7, 15) subcaudals, and females have 169–194 (178 6 7, 9) ventrals and 77–97 (84 6 7, 9) subcaudals. The tail is 25.2–26.9% (26.1 6 0.6, 14) of total length in males and 22.8– 26.0% (24.2 6 1.0, 10) in females. This species has one (68%, 37) or two (32%, 37) primary temporals and two (72%, 37) or three (28%, 37) secondary temporals. Tertiary temporals are usually (62%, 37) absent. A preocular invariably excludes the prefrontal from the orbit, and two (88%, 34) or three (12%, 34) postoculars completely exclude the temporals from the orbit. Peters (1960a) found no specimens with suboculars, however AMNH 6780 has a presubocular on one side. Peters (1960a) noted that the type of D. i. cisticeps has three supralabials entering the orbit on both sides, whereas most (91%, 22 sides) of his Bolivian specimens have only two. We found three supralabials entering the orbit to be slightly more common (23%, 35) than did Peters (1960a, 9%, 11), but still uncommon in this subspecies. Measurements were taken from a limited sample of Bolivian D. bucephala and selected morphometric characters are summarized in Table 3. NK 3516 had an unusually short frontal and its frontal length/width (39.7%) and frontal length/parietal length (27.0%) ratios were left out of ranges and descriptive statistics. In two Bolivian specimens, Peters (1960a) counted 14–15 maxillary teeth. In her field notes for UTA 38081, B. A. Phillips described the iris of this species as being ‘‘golden beige’’ with dark brown reticulation and a very fine ciliary ring. The tongue of this specimen was black with dirty white tines (Harvey & Embert 2008: 65). |
Comment | Distribution: not confirmed in Brazil fide Nogueira et al. 2019 although sometimes reported from Mato Grosso. |
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