Flag for Taxon: Long-beaked Common Dolphin (Delphinus capensis)
| Flagger | Content Author | Content | Reason | Flag Created | Resolved by | Resolution |
|---|---|---|---|---|---|---|
| loarie | Long-beaked Common Dolphin (Delphinus capensis) |
lumped with Delphinus delphis in MDD |
Dec. 3, 2021 00:15:49 +0000 | loarie |
see comments |
Comments
Delphinus capensis is not recognized as a valid species by the Society of Marine Mammalogy. Long story as most taxonomic revisions are, best summarized here:
https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/
"Previous editions of this list recognized two globally distributed species of common dolphins: the short-beaked common dolphin D. delphis and the long-beaked common dolphin D. capensis as proposed by Heyning and Perrin (1994). However, evidence that D. capensis thus considered is a polyphyletic taxon has been accumulating for some time. The long-beaked condition is apparently a convergent character state induced by regional ecology. In some regions, long-beaked common dolphins are genetically more closely related to short-beaked common dolphins than to long-beaked common dolphins in other regions (e.g., see Natoli et al. 2006). Cunha et al. (2015) summarized the relevant data and analyses, along with additional molecular data and analysis, and recommended that Delphinus capensis not be further used as proposed by Heyning and Perrin (1994). That recommendation is followed here. Cunha et al. (2015) noted that because the sympatric/parapatric long-beaked and short-beaked common dolphins off California in the Eastern North Pacific (ENP) appear not to interbreed, perhaps the ENP long-beaked common dolphins might be recognized as a separate species D. bairdii Dall,1873 (as advocated by Banks and Brownell (1969) based on the long-beaked condition). However, the molecular analysis for the ENP (Rosel et al. 1994) did not include common dolphins from the contiguous regions to the south in the eastern tropical and eastern South Pacific. Pending a more complete global review and revision of the common dolphins, the long-beaked ENP form is considered here provisionally as a subspecies D. delphis bairdii following the usage of Hershkovitz (1966). Delphinus capensis Gray,1828 from South Africa remains in the synonymy of Delphinus delphis Linnaeus,1758. The long-beaked common dolphin of the Indian Ocean is retained as a subspecies D. delphis tropicalis."
Looped in duplicate flags https://www.inaturalist.org/flags/559406 & https://www.inaturalist.org/flags/560618
@zebs @jim_carretta @clinton so swap
D. capensis -> D. delphis bairdii
D. capensis capensis -> D. delphis bairdii
D. capensis tropicalis -> D. delphis tropicalis
?
Hi Scott, the advice I have from our marine mammal expert (Anton van Helden, former collection manager of marine mammals at the Museum of New Zealand) is yes, they're all recognised as subspecies of D. delphis now.
Current recognition, would could always change from Society of Marine Mammalogy Taxonomy page:
https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/
Delphinus delphis Linnaeus, 1758. Common dolphin
D. d. delphis Linnaeus, 1758. Common dolphin
D. d. bairdii Dall, 1873. Eastern North Pacific long-beaked common dolphin
D. d. ponticus Barabash, 1935. Black Sea common dolphin
D. d. tropicalis van Bree, 1971. Indo-Pacific common dolphin
great thanks all - I'll make this change. Any input on this related marine mammal issue appreciated https://www.inaturalist.org/flags/554121
Hi all,
I'm a little confused by the notion that all D. capensis observations, save for D. capensis tropicalis, should be moved to D. delphis bairdii. From the MDD D. delphis species-specific notes: "bairdii is likely a distinct species in the north Pacific, but further research is required to confirm this." The Society for Marine Mammalogy refers to bairdii "provisionally as a subspecies"; while it's distinct from sympatric common dolphins in the ENP, a lack of sampling from contiguous regions (eastern tropical and south Pacific) means that issues could arise if it was given species status. In accordance to the Society for Marine Mammalogy's list, only ENP (ssp. bairdii) and Indo-Pacific long-beaked dolphins (ssp. tropicalis) are assigned subspecies, while (for now) the other "long-beaked common dolphins" remain at species-level.
D. capensis ssp. tropicalis (Indo-Pacific) -> D. delphis ssp. tropicalis
D. capensis (ENP) -> D. delphis ssp. bairdii
D. capensis (all other regions) -> D. delphis
This genus has brought up a great deal of confusion, so I'd appreciate hearing everyone's thoughts.
Ok I went ahead and did:
D. capensis ssp. tropicalis -> D. delphis ssp. tropicalis
D. capensis ssp. capensis -> D. delphis
D. capensis -> D. delphis
to be conservative because of mesoplodon's concerns and not wanting to do anything more elaborate. That means there will be some manual IDing work to roll things forward to D. delphis ssp. bairdii, thanks for your help doing this!
And to make things messier, there was a presentation by colleagues this month at the Society of Marine Mammalogy Bienniel meeting that makes a genetics and morphology case for referring to the Eastern North Pacific long-beaked form as a full species, 'Delphinus bairdii'.
Here's the abstract from the meeting and an idea of what's to come:
The eastern Pacific long-beaked common dolphin (Delphinus bairdii): Taxonomic status
and re-description Thomas Jefferson, Frederick (Eric) Archer ,Kelly Robertson
"In the past, neritic, long-beaked common dolphins have been described as species distinct
from the more oceanic and globally distributed short-beaked species, Delphinus delphis,
although recent molecular studies have challenged this view. In the eastern North Pacific
(ENP), the taxonomic status of the long-beaked form has been controversial since its original
description in 1873, and has vacillated back and forth between species, subspecies, and
geographic form several times. It is currently provisionally viewed as a subspecies of D.
delphis (D. delphis bairdii), though this is controversial. To clarify the situation, we
reviewed relevant literature and conducted additional analyses using extensive molecular genetic and cranial morphometric datasets. The results indicate that there are diagnostic
differences in skull morphology and genetics between the ENP long-and short-beaked forms.
Further we found that, despite a large distributional hiatus, the long-beaked population
off Peru (South Pacific) clusters with the ENP long-beaked form. These differences, along with
indications of ecological distinctions, including important differences in life history parameters
and reproductive timing, strongly suggest that the long- and short-beaked forms are on divergent
evolutionary pathways. As such, we consider them to be distinct, though closely related,
species in the eastern Pacific. The long-beaked species is referable to Delphinus bairdii Dall,
1873, and is hereby re-described as such."
should we lump or deviate? Delphinus capensis has ~600 obs