Evolutionary History of Venom Glands in the Siluriformes

Wright, Jeremy J.

doi:10.1007/978-94-007-6458-3_9

Cited by 7 publications

(2 citation statements)

References 45 publications

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“…is probably a case of Müllerian mimicry, since both genera share the defensive tripod formed by the pungent dorsal and pectoral spines (Fine & Ladich, ), a view with which we concur. Moreover, both Callichthyidae and Heptapteridae have venomous species (Wright, , ), which may also be the case for the species discussed here ( Brachyrhamdia spp. can inflict very painful wounds with their pectoral spines; F.C.T.L., pers.…”

Section: Discussionmentioning

confidence: 99%

Deconstructing an octogenarian misconception reveals the true Corydoras arcuatus Elwin 1938 (Siluriformes: Callichthyidae) and a new Corydoras species from the Amazon basin

Tencatt

Lima

Britto

2019

Journal of Fish Biology

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After 80 years of misidentifications, the analysis of the holotype of Corydoras arcuatus plus several non‐type specimens attributed to this species allowed its recognition and also revealed a new species, both sharing the following diagnostic features: a long, arched, continuous black stripe that runs parallel to the dorsal profile of the body and extends at least from the anterior margin of the first dorsolateral body plate to the posterior portion of caudal peduncle; absence of transverse black bars on caudal fin; infraorbital 2 in contact with sphenotic and compound pterotic. In addition to these features, C. arcuatus can be distinguished from congeners by having the posterior margin of both dorsal and pectoral spines with laminar serrations directed towards their origins. The new species can be additionally distinguished from its congeners by presenting the following combination of features: ventral surface of trunk entirely or partially covered by relatively large and coalescent platelets; absence of spots or blotches on dorsal fin; and posterior margin of both dorsal and pectoral spines with serrations directed towards their tips. Finally, an identification key to all arc‐striped species of Corydoras is provided.

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Section: Discussionmentioning

confidence: 99%

Deconstructing an octogenarian misconception reveals the true Corydoras arcuatus Elwin 1938 (Siluriformes: Callichthyidae) and a new Corydoras species from the Amazon basin

Tencatt

Lima

Britto

2019

Journal of Fish Biology

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“…Certain ecological and life history traits may relax selective pressures related to the maintenance of the specialised glands dedicated to venom production, leading to their eventual loss (Morgenstern and King 2013). This phenomenon has been observed in some species of catfish, where increased body sizes effectively protect them from predators, as well as in sea snakes feeding on eggs (Li et al 2005), rendering their venom unnecessary (Wright 2017). One case of secondary loss of venom glands has also been reported in spiders, although with limited evidence.…”

Section: Introductionmentioning

confidence: 99%

Beyond venomous fangs: Uloboridae spiders have lost their venom apparatus but not their toxins

Peng,

Dederichs,

Lüddecke

et al. 2023

Preprint

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Venom is one of the most potent chemical secretions in nature which has played a significant role in the evolutionary success of many animal groups, including spiders. However, the family Uloboridae has seemingly lost the venom-producing organs, leaving the presence and function of toxins in question. Uloborids employ a distinct hunting method involving extensive silk-wrapping and regurgitation of digestive fluids onto the whole prey, yet the precise mechanism by which prey is immobilized remains unknown. One hypothesis is that toxins may have shifted from the venom to other secretions that come into contact with prey, such as silk or digestive fluids. Here, we use a combination of histology and multi-tissue transcriptomics, to 1) investigate the absence of venom glands, and 2) examine the expression of venom toxins in different body parts of Uluborus plumipes. Our findings indicate that U. plumipes effectively does not possess venom glands, nor the duct opening in the fangs. However, we identified putative neurotoxins that are highly expressed in the digestive gland, suggesting that these may contribute to prey immobilization. Among the most highly expressed were U3-aranetoxins, U24-ctenitoxins, and a defensin, although the latter was not predicted to have neurotoxic activity. These results support our hypothesis that Uloboridae spiders have lost their venom apparatus, but not their toxins. These "digestive toxins" might be responsible for complete prey immobilisation and represent an alternative hunting strategy that replaced the loss of a frontal venom system.

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Convergent evolution of venom gland transcriptomes across Metazoa

Zancolli

Reijnders

Waterhouse

et al. 2021

Proc. Natl. Acad. Sci. U.S.A.

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Animals have repeatedly evolved specialized organs and anatomical structures to produce and deliver a mixture of potent bioactive molecules to subdue prey or predators—venom. This makes it one of the most widespread, convergent functions in the animal kingdom. Whether animals have adopted the same genetic toolkit to evolved venom systems is a fascinating question that still eludes us. Here, we performed a comparative analysis of venom gland transcriptomes from 20 venomous species spanning the main Metazoan lineages to test whether different animals have independently adopted similar molecular mechanisms to perform the same function. We found a strong convergence in gene expression profiles, with venom glands being more similar to each other than to any other tissue from the same species, and their differences closely mirroring the species phylogeny. Although venom glands secrete some of the fastest evolving molecules (toxins), their gene expression does not evolve faster than evolutionarily older tissues. We found 15 venom gland–specific gene modules enriched in endoplasmic reticulum stress and unfolded protein response pathways, indicating that animals have independently adopted stress response mechanisms to cope with mass production of toxins. This, in turn, activates regulatory networks for epithelial development, cell turnover, and maintenance, which seem composed of both convergent and lineage-specific factors, possibly reflecting the different developmental origins of venom glands. This study represents a first step toward an understanding of the molecular mechanisms underlying the repeated evolution of one of the most successful adaptive traits in the animal kingdom.

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Evolutionary History of Venom Glands in the Siluriformes

Cited by 7 publications

References 45 publications

Deconstructing an octogenarian misconception reveals the true Corydoras arcuatus Elwin 1938 (Siluriformes: Callichthyidae) and a new Corydoras species from the Amazon basin

Deconstructing an octogenarian misconception reveals the true Corydoras arcuatus Elwin 1938 (Siluriformes: Callichthyidae) and a new Corydoras species from the Amazon basin

Beyond venomous fangs: Uloboridae spiders have lost their venom apparatus but not their toxins

Convergent evolution of venom gland transcriptomes across Metazoa

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