Evolutionary history of burrowing asps (Lamprophiidae: Atractaspidinae) with emphasis on fang evolution and prey selection

Abstract

Atractaspidines are poorly studied, fossorial snakes that are found throughout Africa and western Asia, including the Middle East. We employed concatenated gene-tree analyses and divergence dating approaches to investigate evolutionary relationships and biogeographic patterns of atractaspidines with a multi-locus data set consisting of three mitochondrial ( 16S , cyt b , and ND4 ) and two nuclear genes ( c-mos and RAG1 ). We sampled 91 individuals from both atractaspidine genera ( Atractaspis and Homoroselaps ). Additionally, we used ancestral-state reconstructions to investigate fang and diet evolution within Atractaspidinae and its sister lineage (Aparallactinae). Our results indicated that current classification of atractaspidines underestimates diversity within the group. Diversification occurred predominantly between the Miocene and Pliocene. Ancestral-state reconstructions suggest that snake dentition in these taxa might be highly plastic within relatively short periods of time to facilitate adaptations to dynamic foraging and life-history strategies.

Widespread Evolution of Molecular Resistance to Snake Venom α-Neurotoxins in Vertebrates

“… Sites of positive selection in α1-nAChR ligand-binding domain. Topology constructed from the consensus of TimeTree.org and taxon-specific phylogenies [ 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 ]. The most common amino acid sequence of the α1-nAChR ligand-binding is displayed for one species ( Danio rerio ) and differences from this sequence are displayed for all other species.…”

“…The nucleotide sequences were translated into amino acids, manually aligned, and trimmed down to the 14 codons of the ligand-binding domain using AliView 1.18 ( ) [ 79 ]. A phylogeny of all the species included in our dataset was compiled from a consensus generated by TimeTree.org and reconciled with taxon-specific phylogenies [ 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 ]. The data set was separated into five major clades: Actinopterygii, Mammalia, Archelosauria, toxicoferan lizards, and Serpentes.…”

Snake Venom in Context: Neglected Clades and Concepts

“…To our knowledge, the venoms from these arthropod-eating species have not been studied. Among Lamprophiidae, the subfamily Atractaspidinae includes the rear-fanged genus Aparallactus (11 species) that feeds on centipedes (with the exception of Aparallactus modestus, a fangless species that feeds on earthworms; Portillo et al, 2018Portillo et al, , 2019.…”

“…Among Lamprophiidae, the following rear-fanged genera (belonging to the tribe Atractaspidinae) feed mostly on snakes and fossorial squamates: Amblyodipsas, Brachyophis, Chilorhinophis, Hypoptophis, Macrelaps, Polemon, and Xenocalamus (32 species; Portillo et al, 2018Portillo et al, , 2019. Given its peculiar dentition (enlarged front and back maxillary teeth), use of venom and inclusion of skinks in its diet, the "mock viper" (genus Psammodynastes, 2 species, family Lamprophiidae) also deserves special interest (Jackson and Fritts, 1996).…”

Novelty in three-finger toxin evolution

“…In non-front-fanged snakes, ducts leading from the venom glands open into the mouth near the back of the maxilla [29]. All three of the front-fanged lineages have independently evolved maxillae that are reduced in size and number of teeth, which brings these anterior teeth and associated venom ducts towards the front of the mouth and simplifies the mechanical process of envenomation [30,31]. At the same time, these families' teeth were further adapted to become large (especially in Viperidae and Atractaspidae), tubular fangs which can conduct venom directly from the venom duct into the snake's target [32].…”