Beyond Venom and Constriction: Bite Performance and Trophic Ecology in the Genus Drymarchon

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  Beyond Venom and Constriction: Bite Performance and Trophic Ecology in the Genus Drymarchon Abstract Snakes exhibit extreme cranial kinesis that facilitates ingestion of prey with large cross-sectional area, but this ability is widely predicted to reduce bite performance due to decreased structural rigidity. Consequently, most large-bodied snakes rely on envenomation or constriction to subdue prey prior to ingestion. Species within the genus Drymarchon represent a notable exception: these large, non-venomous, non-constricting snakes routinely consume a wide range of prey, including large and potentially dangerous vertebrates, using only simple seizing and pinioning behaviors. Here, we quantify bite performance in three species of Drymarchon ( D. corais, D. couperi, and D. melanurus ), examine morphological predictors of biting performance, compare biting pressure to constriction pressure in similarly sized snakes, and synthesize dietary records across the genus. Our results sh...

Biogeography of the widespread Aotearoa New Zealand mite harvester genus Rakaia (Arachnida, Opiliones, Cyphophthalmi) based on UCE-derived subgenomic data

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Biogeography of the widespread Aotearoa New Zealand mite harvester genus Rakaia (Arachnida, Opiliones, Cyphophthalmi) based on UCE-derived subgenomic data

Abstract

Aotearoa New Zealand is home to a remarkable number of endemic taxa, some of which have existed on the archipelago since before the breakup of Gondwana. The mite harvesters (suborder Cyphophthalmi), tiny non-spider arachnids that dwell in forest leaf litter and caves, are one such group. The mite harvester family Pettalidae Shear exhibits a classic Gondwanan distribution with notable diversity in Aotearoa, which is home to three pettalid genera. Our research focuses on the evolution of the most widespread and speciose Aotearoa pettalid genus, Rakaia Hirst, 1926. Through phylogenetic analysis, we provide a window into patterns of ancient diversification and infer historical biogeographic trends. We generated subgenomic data through target enrichment of ultraconserved elements (UCEs) using an Arachnida-specific probe set; the 50% and 75% taxon-occupancy matrix retrieved 848 and 585 loci, respectively. In addition to generating the first fully resolved phylogeny of Rakaia, we performed a molecular clock analysis and tested for shifts in diversification rates in order to explore the effect of geological events such as the Oligocene Drowning, the uplift of Kā Tiritiri o te Moana, and forest habitat contraction and fragmentation during the Last Glacial Maximum.

Alafranji, Z. R., Morisawa, R., Aspholm, P. L., Fu, P. A., W. Moyes, N. H., A. Heine, H. L., Hejmadi, S. R., Derkarabetian, S., & Boyer, S. L. (2026). Biogeography of the widespread Aotearoa New Zealand mite harvester genus Rakaia (Arachnida, Opiliones, Cyphophthalmi) based on UCE-derived subgenomic data. Systematic Entomology, 51(1), e70021. https://doi.org/10.1111/syen.70021