Proposed re-organization of Rodentia taxa between Order and Family

Rodentia is the most speciose mammalian order, comprising of about 40% of all living mammals (Behringer et al. 2006). Rodentia is also one of the most "diverse" orders, in a sense that all living members are divided into ~35 families. Compared to Chiroptera, the second most speciose mammalian order, there are no taxonomic ranks between order and family on iNaturalist for Rodentia, nor are there any acknowledged by iNat's external mammal authority, the Mammal Diversity Database (MDD). The lack of such ranks potentially isolates rodent observations at the order level, and transitively limits the potential for a rodent observation to reach a specific identification (e.g. a rodent is "clearly" a caviomorph, but the discrepancies between a slender capybara [Caviidae] and a large agouti [Dasyproctidae] is less apparent to the user, so they leave their ID at "Rodentia"). Additionally, the lack of ranks between order and family make navigating the rodent section of our taxonomic tree potentially more overwhelming, as users see a wall of families with similar vernaculars and scientific names instead of suborders and superfamilies that contain members of more immediately diagnosable relatability.

Even in acknowledgment of these issues, it is understandable why iNat and the MDD do not recognize ranks between order and family. The relatedness between the rodent families has historically been very difficult to understand due to the independent emergence of traits found across distantly related taxa. For a long time, the tenability of groups - particularly suborders such as Castiomorpha and Myomorpha - was dubious. However, the proposal I suggest below follows Fabre et al. 2012. It is an extremely adequate overview of recent phylogenetic work done on rodents and validates the relatedness of certain families (including the tenability of the rodent suborders). With this study in mind (and with slight modifications to accommodate the families recently split [e.g. Zenkrellidae, Sminthidae] - as acknowledged by the MDD), here is my suggested revision of Rodentia (new taxonomic entries are bolded for clarity):

Order Rodentia
Suborder Anomaluromorpha
.....↪ Anomaluridae
.....↪ Pedetidae
.....↪ Zenkrellidae
Suborder Castorimorpha
.....↪ Castoridae
.....↪ Geomyidae
.....↪ Heteromyidae
Suborder Ctenohystrica
.....↪ Infraorder Hystricognathi
..........↪ Parvorder Caviomorpha
...............↪ Superfamily Cavioidea
....................↪ Caviidae
....................↪ Cuniculidae
....................↪ Dasyproctidae
....................↪ Dinomyidae
...............↪ Superfamily Chinchilloidea
....................↪ Abrocomidae
....................↪ Chinchillidae
...............↪ Superfamily Erethizontoidea
....................↪ Erethizontidae
...............↪ Superfamily Octodontoidea
....................↪ Capromyidae
....................↪ Ctenomyidae
....................↪ Echimyidae
....................↪ Octodontidae
..........↪ Bathyergidae
..........↪ Heterocephalidae
..........↪ Hystricidae
..........↪ Petromuridae
..........↪ Thryonomyidae
.....↪ Superfamily Ctenodactyloidea
..........↪ Ctenodactylidae
..........↪ Diatomyidae
Suborder Myomorpha
.....↪ Superfamily Dipodoidea
..........↪ Dipodidae
..........↪ Sminthidae
..........↪ Zapodidae
.....↪ Superfamily Muroidea
..........↪ Cricetidae
..........↪ Calomyscidae
..........↪ Muridae
..........↪ Nesomyidae
..........↪ Platacanthomyidae
..........↪ Spalacidae
Suborder Sciuromorpha
.....↪ Aplodontidae
.....↪ Gliridae
.....↪ Sciuridae

Publicado por bobby23 bobby23, 03 de marzo de 2019

Comentarios

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Tagging my fellow mammal curators for feedback, as well as iNat's resident rodent experts: @jakob @jwidness @maxallen @loarie @sea-kangaroo @nateupham @nba52 @napoleon1799

To clarify, I am the taxon curator for Rodentia on iNaturalist, and I can implement these changes myself. However, this is a significant amount of deviation from the MDD, so I am hesitant to make so many changes without discussing them with others first.

Publicado por bobby23 hace alrededor de 2 años (Marca)
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Yes these are pretty uncontroversial higher-level groupings for Rodentia -- However, the five suborders that you break out can additionally be grouped into Mouse-related clade (Myomorpha, Anomaluromorpha, Castorimorpha ) vs. the Guinea-pig related and Squirrel-related clades. This is the latest convention, although does deviate from latinized names.

See our recent Mammalia-wide species-level phylogeny study, now on bioArxiv here: https://www.biorxiv.org/content/10.1101/504803v1

Those 3 rodent higher-level clades are supported, but the relationships between them are controversial. E.g., see
Blanga-Kanfi, S., H. Miranda, O. Penn, T. Pupko, R. W. DeBry, and D. Huchon. 2009. Rodent phylogeny revised: analysis of six nuclear genes from all major rodent clades. BMC Evolutionary Biology 9:12.
Churakov, G., M. K. Sadasivuni, K. R. Rosenbloom, D. Huchon, J. Brosius, and J. Schmitz. 2010. Rodent Evolution: Back to the Root. Molecular Biology and Evolution 27:1315–1326. http://mbe.oxfordjournals.org/content/27/6/1315
Esselstyn, J. A., C. H. Oliveros, M. T. Swanson, and B. C. Faircloth. 2017. Investigating Difficult Nodes in the Placental Mammal Tree with Expanded Taxon Sampling and Thousands of Ultraconserved Elements. Genome Biology and Evolution 9:2308–2321. https://academic.oup.com/gbe/article/9/9/2308/4095375

Publicado por nateupham hace alrededor de 2 años (Marca)
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Thanks for the response Nate (as well as the literature).

I personally don't mind non-latinized names, but iNaturalist does not currently support "clade" as a rank. I think dividing the rodent families into the five suborders specified above would be suffice for iNaturalist.

Is there any specific reason why the MDD does not recognize higher classification ranks for rodents, @nateupham @jwidness ?

Publicado por bobby23 hace alrededor de 2 años (Marca)
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Hey Bobby -- no, no specific reason why the MDD doesn't have more higher rank categories. Its something we will look into for the next revision. I agree that they are super useful as long as up-to-date with the latest phylogenetic results.

Publicado por nateupham hace alrededor de 2 años (Marca)

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