Clarifying the ID confusion on New Zealand *Dendrodoris nigra* complex (Nudibranch-Phylum Mollusca)

Hi all,

Currently, on iNatNZ, two scientific names are used for the Black doris found in NZ.
Based on their colourations they appear to be D. arborescens at some point instead of D. nigra which is the name used more often. However, there has been no reliable genetical studies about them, and also their colourations are known to be extremely variable.

Therefore, on iNaturalist, we should leave all their IDs to the genus level (Dendrodoris sp.) or use the name popular in NZ, *D. nigra*, until a peer-reviewed article about them clarifies which one is the species in NZ , or if both species occur in NZ.

(Although previously D. nigra was registered as species complex on iNat, it is usually best not to use species complex and it is no longer listed)

If you agree with this, please help update IDs of D. arborescens from the Identify page. Since Zach and I have updated IDs to D. nigra or D. sp. , many of the observations are currently needing IDs at genus level. Thank you!

Note: iNaturalist is not a place to discuss taxonomy and iNat only aims to preserve good records of wild organisms, so it is usually best to stick with the most often used names, unless there is evidence which suggests that it is not accurate.

This has been discussed in @fiestykakapo 's journal(url) previously, however most people hasn't updated their IDs yet, which is why I am writing this again.

Please comment below if you have any questions about it or if disagree, and I am happy to discuss about it :-)

Mentioning main identifiers and observers of genus Dendrodoris observed in NZ (random order):

@predomalpha
@fiestykakapo
@clinton
@stephen_thorpe
@hsini_lin
@sam_15
@luca_dt
@simonnicholas
@sascha_schulz

@erwinkoehler

@tangatawhenua

@jpsilva

@shaun-lee

@lloyd_esler
@lisa_bennett
@drmattnimbs

@jordi_nz
@vie
@lcolmer
@emr_auckland

@shaun-lee
@jordi_nz
@mette10
@simonf7532

@chicky67

@jhanwell

@lawrencetroup
@titine
@daan_hoffmann

@jacqui-nz

@albeer23

@beaumasters

@emma_brockes
@indeynz

@oscar_dove
@sam_15
@shanmonkey31

Thanks,

Saryu Mae / Glycymeris

Posted on 02 September, 2022 19:43 by invertebratist invertebratist

Comments

@glycymeris Thanks for posting your thoughts, however, there are a few points you make that I disagree with.

Firstly, iNaturalist is a place to discuss taxonomy. Given that identifications are crowd based, it is vital that taxonomy, identification and characteristics are discussed so that people may become aware of them.

The statement that black dorids in NZ should be kept as D. nigra in the absence of a study that doesnt identify another species present, even though colour variants are found there, and have been identified as another species on the western side of the same body of water is only one argument. To support this using the further argument that D. nigra should be kept for NZ animal because "that's what it's always been called" is very weak.

Identifying animals that look like D. arborescens as D. arborescens is not 'creating an unstable' taxonomic situation. It is identifying a species based on the known characters and in reference to the literature current at the time. If the literature fails to note D. arborescens as present in NZ, that does not mean that it doesn't, it simply means that black dorids in NZ have not been thoroughly studied. There is plenty of material there, but no one has done it. A call to leave the identification as one until its proven to be another is only one argument. The reverse is also true. Obviously its always better to not have a misidentification, and a consensus is always desirable, but I disagree that iNaturalist users should follow a call to amend their own identification based on these points.

Posted by drmattnimbs over 1 year ago

Agree with Matt (@drmattnimbs)!

Posted by hsini_lin over 1 year ago

@drmattnimbs @hsini_lin
Thanks for your comments :)

Dendrodoris nigra is also known to be extremely variable and I am sure that someone will make the border clear in the future using DNA. At the moment I don't think there is a perfect way to tell these two species apart, especially considering that there must be a lot of misidentifications in the past as well. Therefore we don't want to make the situation more confusing by identifying them as D. arborescens which is different to the name recognized within NZ.
It might be the best to put back Complex status for D. nigra so it will be clear that we don't mean D. nigra [sensu stricto].

Also, iNat policy clearly notes that iNaturalist is not a place to argue about taxonomy.
"Following taxonomic authorities helps us avoid having these arguments on iNat. We can argue about which authorities to follow, but following authorities allows us to skip arguments about each and every paper"
https://www.inaturalist.org/pages/curator+guide#policies

Of course my post is just a suggestion, and all identifiers should decide which ID to add based only on their thoughts.

Posted by invertebratist over 1 year ago

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