#Orcinus ater

[inatungulates]

And while I'm posting about taxonomy, I just found out that I missed the resurrection of Subulo for the common brown brocket "Mazama" gouazoubira, so I'll likely be updating that soon... though, I wonder if anything else will be placed in the genus? Mazama sensu lato is all over the place.

Also, the first steps of the big killer whale revision have been taken, but I may be slower to implement Orcinus rectipinnus and Orcinus ater (in part because several killer whale observations I have from the Eastern North Pacific may not be readily IDable to one form or the other, and in part because I'm hoping more stuff will follow soon).

[cmipalaeo]

It is worth pointing out that the authors aren’t claiming that the Bigg’s and Eastern North Pacific residents are the most different killer whales in the world and that the rest of Orcinus orca is one thing — just that these two are the best-studied so providing evidence of their distinctness is most straightforward. In their cladogram (which I confess I don’t remember what its basis is — mtDNA or what) the Bigg’s and ENP residents are very well separated, with Bigg’s being pretty much the basalmost member of the group apart from subantarctic “Type D”.

So what we’re seeing here is a breaking of the ice — if this meets with general acceptance, I think we’ll see a quickening of the recognition of the other ecotypes as new species as well. The cladogram in this study showed both Antarctic Type Bs to form a clade with Type C, so that would be an interesting case — a single species with three subspecies, two species with one monotypic and one with two subspecies, or three species…

🚨 A team of scientists, led by Phil Morin of NOAA, have published a new paper formally proposing two “new” species of killer whale: Bigg’s killer whales (Orcinus rectipinna) and resident killer whales (Orcinus ater).🚨

More than fifty years ago, researchers began studying the killer whales found off the west coast of North America. One keen-eyed scientist, Dr. Michael Bigg, noticed that there appeared to be two kinds of killer whales: a smaller, more gregarious form that fed on fish and a larger, stealthier type that fed on marine mammals. He and his colleagues dubbed the fish-eaters “resident” killer whales and the mammal-eaters “transient” killer whales (who were later renamed Bigg’s killer whales in his honor).

Two female Bigg’s killer whales in Washington (top) and a male and female resident killer whale in Alaska (bottom)

Many decades later, scientists have been hard at work trying to resolve whether or not these two forms are different species. It is not an easy task. This requires a thorough investigation into many factors, including evolutionary history, genetics, morphology, ecology, and behavior. In this paper, the researchers lay out all of the evidence and conclude that these two forms warrant elevation to species status.

As newly proposed species, both need new scientific names. There have been numerous killer whale species proposed and described in the past by other naturalists and researchers, including those in the North Pacific. Unfortunately, there are no type specimens— individual specimens upon which the first descriptions of a species are based—available for killer whales previously described from the North Pacific, so the researchers were left to examine drawings and illustrations of killer whales in the North Pacific in the late 1800s by Scammon and Cope.

The authors propose “Orcinus rectipinnus” for Bigg’s killer whales and “Orcinus ater” for resident killer whales. “Rectipinnus” presumably refers to tall dorsal fins, and “ater” means “black” or “dark” in Latin. Of note is the fact that a female killer whale from California originally examined and described by Scammon as “Orcinus rectipinnus” had seals in her stomach, suggesting she was a Bigg’s killer whale.

In addition, the authors note they are consulting with Indigenous tribes for a new common name for resident killer whales.

What’s next? In marine mammal biology, proposed taxonomic changes are reviewed by the Society for Marine Mammalogy’s taxonomy committee. If accepted, these species revisions become “official.” This has been an eagerly awaited paper by many in the field of killer whale biology and it is a great accomplishment, made possible by decades of research by scientists around the world.

A big thank you to lead author Phil Morin for letting me preview the manuscript and for answering my numerous questions in preparation for this post!

Read the paper here!

[kaijudyke]

DID YOU HEAR ABOUT THE NEW ORCA SPECIES

i'm assuming you're talking about the proposed distinction between resident and transient orcas? i had to check bc i hadn't actually seen that a decision had been made (i did see when the study came out a few months back so i knew it had been proposed) and it looks like they haven't actually been accepted as separate species but are for the moment being recognized as distinct subspecies. the society for marine mammalogy's list of marine mammal species and subspecies currently lists them like this:

Orcinus orca (Linnaeus, 1758). Killer whale, orca

O. o. ater (Cope in Scammon, 1869). Resident killer whale

O. o. orca (Linnaeus, 1758). Common killer whale

O. o. rectipinnus (Cope in Scammon, 1869). Bigg’s killer whale

and this is what the text says about it:

Based on genetic, morphological and ecological data, Morin et al. (2024) provided a taxonomic revision for two ecotypes of Orcinus orca in the eastern North Pacific: Bigg’s killer whale (also known as transient ecotype) and the resident killer whale. The level of differentiation observed led the authors to recommend their recognition as distinct species: O. rectipinnus (Bigg’s killer whale) and O. ater (resident killer whale). Although the majority of the voting members recognize the high level of differentiation between the two ecotypes in all the evidence presented in Morin et al. (2024), there was uncertainty whether this diagnosability represented species- or subspecies-level designation. Some points argued against species designation at the time included: 1) the nesting of both clades within the wider O. orca clade in the mitogenome phylogeny; 2) presence of episodic gene flow among the ecotypes, which needs further investigation; and 3) the need to conduct a more comprehensive analysis on a global context to better understand how distinct these two ecotypes are from other Orcinus orca clades, including those found at latitudes below ~34º N off the coasts of California and Mexico and the more northerly Bigg’s and offshore ecotypes, which were not evaluated in the paper. Previously, the Committee followed the recognition in Krahn et al. (2004) of two un-named subspecies of killer whales for the eastern North Pacific, which were listed in previous version of the List of Proposed Un-named Species and Subspecies. These two un-named subspecies correspond to the resident and Bigg’s/transient ecotypes, respectively. Therefore, pending a more complete global review and revision of the killer whales, the two ecotypes are considered here provisionally as distinct subspecies of Orcinus orca and named following Morin et al. (2024): O. orca ater (resident killer whale) and O. orca rectipinnus (Bigg’s killer whale), with O. orca orca (common killer whale) as the nominate subspecies.

it remains to be seen how everything shakes out after further research! thanks for prompting me to check back in with this, it had totally slipped my mind and if anyone i follow has talked about it since the decision was made it's escaped my notice. it's such a shame residents and transients are so much easier to study (and so much better understood as a result) than other ecotypes, i would love to see a really thorough examination of every extant ecotype and a judgment on speciation more broadly. i know they argue for this in the text but of course there's a reason the paper only covered two ecotypes. it feels so weird to see residents and transients listed next to "common killer whale" as if the rest of them are all the same! have you seen what a type D looks like?? i hope we get to learn more about the less studied ecotypes in the not too far future and that future decisions like this can have a broader scope!