In praise of subgenera: taxonomic status of cobras of the genus Naja Laurenti (Serpentes: Elapidae)

Wallach, Van; Wüster, Wolfgang; Broadley, Donald G.

doi:10.11646/zootaxa.2236.1.2

Cited by 60 publications

(59 citation statements)

References 36 publications

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“…These taxa ( P. reticulatus and P. timoriensis ) have been referred to as Broghammerus , a name originating from an act of "taxonomic vandalism" (i.e. an apparently intentional attempt to disrupt stable taxonomy) in a non-peer reviewed organ without data or analyses [163,164]. However, this name was, perhaps inadvertently, subsequently used by researchers in peer-reviewed work [165] and has entered into somewhat widespread usage [1].…”

Section: Resultsmentioning

confidence: 99%

A phylogeny and revised classification of Squamata, including 4161 species of lizards and snakes

2013

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BackgroundThe extant squamates (>9400 known species of lizards and snakes) are one of the most diverse and conspicuous radiations of terrestrial vertebrates, but no studies have attempted to reconstruct a phylogeny for the group with large-scale taxon sampling. Such an estimate is invaluable for comparative evolutionary studies, and to address their classification. Here, we present the first large-scale phylogenetic estimate for Squamata.ResultsThe estimated phylogeny contains 4161 species, representing all currently recognized families and subfamilies. The analysis is based on up to 12896 base pairs of sequence data per species (average = 2497 bp) from 12 genes, including seven nuclear loci (BDNF, c-mos, NT3, PDC, R35, RAG-1, and RAG-2), and five mitochondrial genes (12S, 16S, cytochrome b, ND2, and ND4). The tree provides important confirmation for recent estimates of higher-level squamate phylogeny based on molecular data (but with more limited taxon sampling), estimates that are very different from previous morphology-based hypotheses. The tree also includes many relationships that differ from previous molecular estimates and many that differ from traditional taxonomy.ConclusionsWe present a new large-scale phylogeny of squamate reptiles that should be a valuable resource for future comparative studies. We also present a revised classification of squamates at the family and subfamily level to bring the taxonomy more in line with the new phylogenetic hypothesis. This classification includes new, resurrected, and modified subfamilies within gymnophthalmid and scincid lizards, and boid, colubrid, and lamprophiid snakes.

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Section: Resultsmentioning

confidence: 99%

A phylogeny and revised classification of Squamata, including 4161 species of lizards and snakes

2013

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“…The continued recognition of the Bitis subgenera, however, does provide an effective way of highlighting the major evolutionary and ecological divisions within the genus whilst avoiding any potentially negative effects of generic reassignment. Overall, this results in a more information‐rich classification (Wallach, Wüster, & Broadley, ).…”

Section: Discussionmentioning

confidence: 99%

Ancient habitat shifts and organismal diversification are decoupled in the African viper genus Bitis (Serpentes: Viperidae)

Barlow

Wüster

Kelly

et al. 2019

Journal of Biogeography

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Aim The expansion of open habitats during the mid‐Miocene has been hypothesized as a driver of allopatric speciation for many African taxa. This habitat‐dependent mode of diversification has been implicated in the shift from C3 (e.g. forest/woodland) to C4 dominated systems (i.e. open savanna, grasslands) in a number of African squamates. We examined this hypothesis using a genus of African viperid snakes (Bitis) with both open habitat and forest‐dwelling representatives. Location Africa. Methods A comprehensive multilocus dataset was used to generate a calibrated species tree using a multispecies coalescent model. Individual gene trees and patterns of nuclear allele sharing were used to assess species monophyly and isolation. To test the habitat‐dependent evolution hypothesis, we generated an ancestral character state reconstruction for open and closed habitats using the dated phylogeny. This was related to the timing of open habitat expansion and forest/woodland contraction in Africa. Results The genus Bitis originated in the Oligocene, with species level diversification in the late Miocene/Pliocene. Four well‐supported clades correspond to the recognized subgenera Bitis, Keniabitis, Macrocerastes and Calechidna. Several previously unrecognized lineages potentially represent cryptic species. Main conclusions Habitat‐dependent evolution does not appear to have been a main driver for generic level viperine diversification: the ancestral state for Bitis was open habitat and at least one clade moved into forest in the Miocene, long after forest had contracted and fragmented. Forest‐dependent species diversified only in the late Miocene, presumably as forest became further reduced in extent, fitting an allopatric model of speciation. Although our results do not favour a general pattern of habitat‐dependent diversification in Bitis, cladogenesis within the subgenus Calechidna for “arenicolous” species (Bitis caudalis complex) and “rupicolous” species (B. atropos‐cornuta complex), corresponds to the aridification of southwest Africa. This suggests there are subtleties not captured in the broad open habitat category, which are relevant for understanding the role of habitat‐dependent evolution.

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“…Hooding is a distinctive characteristic of the genera Hemachatus , Naja and Ophiophagus and members of these genera are found in Africa and Asia [22]. Since Ophiophagus is not closely related to Naja and Hemachatus [15,17], hooding has likely evolved on at least two separate occasions.…”

Section: Introductionmentioning

confidence: 99%

How the Cobra Got Its Flesh-Eating Venom: Cytotoxicity as a Defensive Innovation and Its Co-Evolution with Hooding, Aposematic Marking, and Spitting

Panagides

Jackson

Ikonomopoulou

et al. 2017

Toxins

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The cytotoxicity of the venom of 25 species of Old World elapid snake was tested and compared with the morphological and behavioural adaptations of hooding and spitting. We determined that, contrary to previous assumptions, the venoms of spitting species are not consistently more cytotoxic than those of closely related non-spitting species. While this correlation between spitting and non-spitting was found among African cobras, it was not present among Asian cobras. On the other hand, a consistent positive correlation was observed between cytotoxicity and utilisation of the defensive hooding display that cobras are famous for. Hooding and spitting are widely regarded as defensive adaptations, but it has hitherto been uncertain whether cytotoxicity serves a defensive purpose or is somehow useful in prey subjugation. The results of this study suggest that cytotoxicity evolved primarily as a defensive innovation and that it has co-evolved twice alongside hooding behavior: once in the Hemachatus + Naja and again independently in the king cobras (Ophiophagus). There was a significant increase of cytotoxicity in the Asian Naja linked to the evolution of bold aposematic hood markings, reinforcing the link between hooding and the evolution of defensive cytotoxic venoms. In parallel, lineages with increased cytotoxicity but lacking bold hood patterns evolved aposematic markers in the form of high contrast body banding. The results also indicate that, secondary to the evolution of venom rich in cytotoxins, spitting has evolved three times independently: once within the African Naja, once within the Asian Naja, and once in the Hemachatus genus. The evolution of cytotoxic venom thus appears to facilitate the evolution of defensive spitting behaviour. In contrast, a secondary loss of cytotoxicity and reduction of the hood occurred in the water cobra Naja annulata, which possesses streamlined neurotoxic venom similar to that of other aquatic elapid snakes (e.g., hydrophiine sea snakes). The results of this study make an important contribution to our growing understanding of the selection pressures shaping the evolution of snake venom and its constituent toxins. The data also aid in elucidating the relationship between these selection pressures and the medical impact of human snakebite in the developing world, as cytotoxic cobras cause considerable morbidity including loss-of-function injuries that result in economic and social burdens in the tropics of Asia and sub-Saharan Africa.

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In praise of subgenera: taxonomic status of cobras of the genus Naja Laurenti (Serpentes: Elapidae)

Cited by 60 publications

References 36 publications

A phylogeny and revised classification of Squamata, including 4161 species of lizards and snakes

A phylogeny and revised classification of Squamata, including 4161 species of lizards and snakes

Ancient habitat shifts and organismal diversification are decoupled in the African viper genus Bitis (Serpentes: Viperidae)

How the Cobra Got Its Flesh-Eating Venom: Cytotoxicity as a Defensive Innovation and Its Co-Evolution with Hooding, Aposematic Marking, and Spitting

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