Sharp and fully loaded: 3D tissue reconstruction reveals how snake fangs stay deadly during fang replacement. Issue 1 (3rd August 2021)

• Record Type: Journal Article
• Authors: Cleuren, Silke G. C.; Parker, William M. G.; Richards, Hazel L.; Hocking, David P.; Evans, Alistair R.
• Is Part Of: Journal of anatomy. Volume 240:Issue 1(2022)
• Page Start: 1
• Page End: 10
• Publication Date: 2021-08-03
• Subjects: DiceCT -- fangs -- tooth replacement -- venom delivery system -- venom duct -- venomous snakes; Anatomy -- Periodicals; 571.3
• DOI: 10.1111/joa.13531
• Languages: English
• ISSNs: 0021-8782

Abstract

Abstract: Snake venom is produced, transported and delivered by the sophisticated venom delivery system (VDS). When snakes bite, the venom travels from the venom gland through the venom duct into needle‐like fangs that inject it into their prey. To counteract breakages, fangs are continuously replaced throughout life. Currently, the anatomy of the connection between the duct and the fang has not been described, and the mechanism by which the duct is reconnected to the replacement fang has not been identified. We examined the VDS in 3D in representative species from two families and one subfamily (Elapidae, Viperidae, Atractaspidinae) using contrast‐enhanced microCT (diceCT), followed by dissection and histology. We observed that the venom duct bifurcates immediately anterior to the fangs so that both the original and replacement fangs are separately connected and functional in delivering venom. When a fang is absent, the canal leading to the empty position is temporarily closed. We found that elapid snakes have a crescent‐shaped venom reservoir where venom likely pools before it enters the fang. These findings form the final piece of the puzzle of VDS anatomy in front‐fanged venomous snakes. Additionally, they provide further evidence for independent evolution of the VDS in these three snake taxa. Abstract : The connection between snake fang and venom gland is presented alongside the maintenance of these connections during the process of fang replacement, using histological imaging and diceCT. A bifurcating connection with both the original and replacement fang was observed, allowing both fangs to be functional at delivering venom. Differences across front‐fanged families was observed, where a venom reservoir anterior to the fang was only observed in Elapidae.