Friday, October 21, 2016

Bushmaster, Lachesis muta (Family Viperidae)

Other common names: Pineapple snake, mapepire zanana. Size: 2 m, maximum TL 3353 m; at hatching 350−380 mm. Triangular rostral not visible from above; nostrils very anterior, open laterally in a divided nasal; heat-sensing pits located in the second labial scale which is fused with the prelacunal scale; preocular large and separated from nasal by a small loreal; 2–3 very small postoculars; two pairs of enlarged scales above the nasals; remaining scales on crown small and somewhat granular, except for large supraoculars; subocular elongate in Trinidad specimens, but divided in specimens from elsewhere in the range; between subocular and upper labials four rows of small scales; upper labials 9–10, lower labials 12–17; first pair of lower labials form the mental groove with the single pair of enlarged chin shields; dorsal scales in first row are smooth and ovate, scales in rows 2–6 are smooth to weakly keeled; and scales closest to midline are lanceolate, strongly keeled with raised conical keels. Dorsal scale rows at midbody 27 in one Trinidad specimen when small abnormal scales are omitted from the count. Ventrals 200–230, cloacal plate single, 32–50 paired subcaudals (but some may be single). Crown of head uniform or slightly spotted with dark blotches; dark postocular stripe extending above and past the comer of mouth; body with 25 transverse blotches that may fuse on the midline; blotches narrow toward ventrals and expand toward midline; dark pigment predominates on tail and is separated by narrow tan or orange-brown rings. Large triangular head distinct from neck, dorsum usually yellow with darker triangular markings; scales with conical keels given the skin a rough appearance; 9 or 10 upper labials and distal subcaudals divided into five rows will distinguish this snake from the Trinidad Bothrops. Occurs in greater Amazonia and Trinidad; widespread on Trinidad, but limited by human activity. Habitat: Forest dweller often associated with agouti, paca, or armadillo burrows. Nocturnal. Often sits in ambush for long periods of time, along fallen trees or tree buttresses. When not hunting or searching for mates these snakes are likely spending most of their time underground in the burrows of the mammals noted above. Diet mostly mammals. Juvenile bushmasters have a yellow tail tip suggesting that they may use caudal luring to obtain prey, but this has not yet been documented. Bushmasters are the only documented New World pitviper to lay eggs, although anecdotal evidence suggests there is another species that does so. Egg laying was first reported in bushmasters from Trinidad by Raymond Ditmars. Captive female bushmasters that lay eggs attend them by coiling around the clutch. Clutches of 6−12 eggs reported for this species with an incubation period of 60−69 days. Captive have been reported to live for more than 16 years, but Trinidad specimens have the reputation for not living long after capture and pentastomid parasites (lungworms) are suspected of being the cause of death.

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