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Taxacom: supposed evidence of Pacific ignuana dispersal

Michael Heads m.j.heads at gmail.com
Sat Mar 22 05:25:29 CDT 2025 

If protoiguanid-agamids, and then pre-  and proto-iguanids were already in
the west Pacific, there is no need for fully-fledged iguanids, let alone
Brachylophus, to migrate anywhere. The allopatry within Iguania
(pleurodonts - Fiji and east, vs acrodonts - Solomons and west) is the key
to the family distribution boundaries there (i.e.
phylogenetic-biogeographic breaks), but the authors don't mention it.

On Sat, Mar 22, 2025 at 9:45?PM Geoff Read via Taxacom <taxacom at lists.ku.edu>
wrote:

>
> No Michael, they don't "just say" that.  There is extensive discussion
> including of a Eurasian etc origin and they seem to cover every prior
> hypothesis.Don't go way up the classification.  Do that and anything is a
> possibility.Down at the subfamily level of Iguaninae their work links
> Fijian species Brachylophus bulabula in a clade with Dipsosaurus dorsalis
> of the Southwestern United States and northwestern Mexico. And the other
> iguanas nearby in their tree are N. American, Galapagos, and Antilles.The
> tree as published is the salient part, not the full tree, which would be
> nice to see - apparently that is in the supplementary data.
> Geoff
>
> --
> Geoffrey B. Read, Ph.D.
> Wellington, NEW ZEALAND
> gread at actrix.gen.nz
>
> ---- Original Message ----
> From: Michael Heads
> To: "Geoff Read"
> Cc: "taxacom"
> Sent: Sat, Mar 22, 2025, 5:27 PM
> Subject: Re: Taxacom: supposed evidence of Pacific ignuana dispersal
>
>   They just say: 'Pleurodonta = Iguanidae sensu ( 16 ) (e.g., anoles,
> horned lizards, and relatives), are also largely restricted to the western
> hemisphere'.  They don't mention the sister group, let alone vicariance
> with it, although it's a classic case of vicariance that's been cited many
> times.
>       Pleurodonta: Madagascar + Americas + Fiji/Tonga. (i..e trans-Pacific
> + Atlantic).
>       Acrodonta (sis group of Pleurodonta): Madagascar + Africa + Europe +
> Asia to Australia and Solomons. (Trans-Indian).
> The groups are allopatric except in Madagascar. The distributions are
> determined by breaks (of a global ancestor) in the Atlantic, around
> Madagascar, and between the Solomons and Fiji, all areas of major rifting.
> There is no dispersal indicated except (perhaps) in Madagascar.
> On Sat, Mar 22, 2025 at 12:26?PM Geoff Read via Taxacom  wrote:
>  Here's one of the news articles mentioned by John.
>
> https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fapnews.com%2Farticle%2Figuana-fiji-raft-float-journey-travel-9732d828c28a8374a6873fbc1b3d4af2&data%7C02%7Ctaxacom%40lists.ku.edu%7C257f32bac53a4bdaa37708dd692be6a1%7C3c176536afe643f5b96636feabbe3c1a%7C0%7C0%7C638782359905598376%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C60000%7C%7C%7C&sdata=PDD82Strv73phZu8fallGLMt%2B50%2FVFDHfX%2FK4uaahOM%3D&reserved=0
> (
> https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fapnews.com%2Farticle%2Figuana-fiji-raft-float-journey-travel-9732d828c28a8374a6873fbc1b3d4af2&data%7C02%7Ctaxacom%40lists.ku.edu%7C257f32bac53a4bdaa37708dd692be6a1%7C3c176536afe643f5b96636feabbe3c1a%7C0%7C0%7C638782359905615361%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C60000%7C%7C%7C&sdata=p2DIKgzFuHfP6ZE%2BbIi4F7s8%2BYeaB%2F9%2FZVjDEkcz1oY%3D&reserved=0
> )
>  I've read the PNAS article and it does seem to be a very thorough
> even-handed assessment of all the possibilities in their discussion.
>  They say humans have observed iguanas making landfall on islands and quote
> this presumably famous instance:
>  "In 1995, a vegetation mat
>  with at least 15 individual green iguanas (Iguana iguana) that likely
>  originated on the islands of Guadeloupe was observed making landfall
>  on Anguilla, an island 300 km away that was already inhabited by
>  a different species of iguana, I. delicatissima"
>  One quibble is that they work at a genus-level with little mention of
> species.  The genus is an 'it' as though it is a physical entity. A
> practice more familiar of palaeontologists rather than molecular
> biologists.
>  This quote illustrates the style:  "Brachylophus , which contains 4 extant
> and 1 extinct species, is morphologically divergent from other iguanas and
> occurs extremely far from all of its extant relatives"
>  Substitute 'are' for 'is' and 'their' for 'its' and see how it reads. The
> actual species is Brachylophus bulabula.  It gets just one mention (in a
> figure), and there are relations on different Fijian islands, plus
> apparently also one iguana human-transported.
>  --
>  Geoffrey B. Read, Ph.D.
>  Wellington, NEW ZEALAND
>  gread at actrix.gen.nz (mailto:gread at actrix.gen.nz)
>  >---- Original Message ----
>  >From: John Grehan via Taxacom
>  >To: "taxacom"
>  >Sent: Fri, Mar 21, 2025, 9:33 AM
>  >Subject: Taxacom: supposed evidence of Pacific ignuana dispersal
>  >
>  >Some of you may have seen this as it's been splashed around widely on the
>  >propaganda circuit.
>  >
>  >Iguanas rafted more than 8,000 km from North America to Fiji PNAS 2025
> Vol.
>  >122 No. 12 e2318622122 https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdoi.org%2F10.1073%2Fpnas.2318622122&data%7C02%7Ctaxacom%40lists.ku.edu%7C257f32bac53a4bdaa37708dd692be6a1%7C3c176536afe643f5b96636feabbe3c1a%7C0%7C0%7C638782359905628325%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C60000%7C%7C%7C&sdata=eqj31WLrwSGCH1cxC2Ztf80oU8Skc3TL9bSo%2Bc2M1nc%3D&reserved=0
> (https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdoi.org%2F10.1073%2Fpnas.2318622122&data%7C02%7Ctaxacom%40lists.ku.edu%7C257f32bac53a4bdaa37708dd692be6a1%7C3c176536afe643f5b96636feabbe3c1a%7C0%7C0%7C638782359905639869%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C60000%7C%7C%7C&sdata=UoqFWWu0s3fYQXZ7SHR5GAYNRXK3EE8N4P5bvePZsec%3D&reserved=0)
>  >
>  >It's just another duplication of the same old trash. Abstract claims that
>  >?Here, we investigate the occurrence and timing of the greatest known
>  >long-distance oceanic dispersal event in the history of terrestrial
>  >vertebrates?the rafting of iguanas from North America to Fiji.?
> Trouble
>  >with this is that it makes out that this ?long-distance oceanic
> dispersal
>  >event? is an established scientific fact when it is not.
>  >
>  >
>  >Then they assert that ?Iguanas are large-bodied herbivores that are
>  >well-known overwater dispersers, including species that colonized the
>  >Caribbean and the Gal?pagos islands.? when there is absolutely no
>  >empirically based evidence that the Galapagos iguanas ever dispersed
>  >overwater to the Galapagos.
>  >
>  >
>  >
>  >And the central rot (as in decay) of their claims is the same as all the
>  >other center of origin-chance dispersal recipes: The divergence estimate
> is
>  >based on fossil calibration which can only render minimum ages. Anything
>  >else (such as priors) is conjecture. So their timeline is erroneous in
> this
>  >respect. The other is that their ancestral-areas analysis is simply a
>  >recipe that cannot empirically distinguish between chance dispersal and
>  >vicariance as either can generate the same phylogenetic area sequence.
>  >
>  >
>  >
>  >Given their calling attention to the Galapagos it seems an incredible
>  >oversight to have missed Heads & Grehan 2021 on Galapagos biogeography,
>  >including the Fiji connection. I've seen this before, where there is a
>  >narrow range of citations restricted to the same school of thought.
>  >Anything else does not exist. This, then, is the pinnacle of academic
>  >achievement in the US (maybe a good argument for the government trashing
>  >science?).
>  >
>  >
>  >Cheers, John
>  _______________________________________________
>  Taxacom Mailing List
>  Nurturing nuance while assailing ambiguity for 38 years, 1987-2025.
>  Send Taxacom mailing list submissions to: taxacom at lists.ku.edu
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> --
> Dunedin, New Zealand.
> My books:
>         Biogeography and evolution in New Zealand. Taylor and Francis/CRC,
> Boca
> Raton FL. 2017.
>
> https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.routledge.com%2FBiogeography-and-Evolution-in-New-Zealand%2FHeads%2Fp%2Fbook%2F9781498751872&data%7C02%7Ctaxacom%40lists.ku.edu%7C257f32bac53a4bdaa37708dd692be6a1%7C3c176536afe643f5b96636feabbe3c1a%7C0%7C0%7C638782359905651244%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C60000%7C%7C%7C&sdata=0vA3zyyHYRH6eElgTsgvuNzf%2BwZZHxApteaLcWs7d6I%3D&reserved=0
> (
> https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.routledge.com%2FBiogeography-and-Evolution-in-New-Zealand%2FHeads%2Fp%2Fbook%2F9781498751872&data%7C02%7Ctaxacom%40lists.ku.edu%7C257f32bac53a4bdaa37708dd692be6a1%7C3c176536afe643f5b96636feabbe3c1a%7C0%7C0%7C638782359905664783%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C60000%7C%7C%7C&sdata=SVenldAt3i3qdc2YkYCw0T1YlZdxwte7h9q0%2BbeXPaM%3D&reserved=0
> )
>         Biogeography of Australasia:  A molecular analysis. Cambridge
> University
> Press, Cambridge. 2014. https://nam10.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.cambridge.org%2F9781107041028&data%7C02%7Ctaxacom%40lists.ku.edu%7C257f32bac53a4bdaa37708dd692be6a1%7C3c176536afe643f5b96636feabbe3c1a%7C0%7C0%7C638782359905677506%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C60000%7C%7C%7C&sdata=0WqFkeD1BaaN%2FbmrMUMYB6%2B3tL3rUwDeO8O0VJ2p4C0%3D&reserved=0
> (https://nam10.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.cambridge.org%2F9781107041028&data%7C02%7Ctaxacom%40lists.ku.edu%7C257f32bac53a4bdaa37708dd692be6a1%7C3c176536afe643f5b96636feabbe3c1a%7C0%7C0%7C638782359905690966%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C60000%7C%7C%7C&sdata=T8xPcx8WdM9ECV2MmKdRcWuSldwBJUPYXVxWvEQZ%2BVM%3D&reserved=0)
>         Molecular panbiogeography of the tropics. University of California
> Press,
> Berkeley. 2012. https://nam10.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.ucpress.edu%2Fbook.php%3Fisbn%3D9780520271968&data%7C02%7Ctaxacom%40lists.ku.edu%7C257f32bac53a4bdaa37708dd692be6a1%7C3c176536afe643f5b96636feabbe3c1a%7C0%7C0%7C638782359905704500%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C60000%7C%7C%7C&sdata=Zcng%2FPURoVxMkpOQIMHjouXID6fFkpxEIJFxZnG8igY%3D&reserved=0
> (https://nam10.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.ucpress.edu%2Fbook.php%3Fisbn%3D9780520271968&data%7C02%7Ctaxacom%40lists.ku.edu%7C257f32bac53a4bdaa37708dd692be6a1%7C3c176536afe643f5b96636feabbe3c1a%7C0%7C0%7C638782359905717277%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C60000%7C%7C%7C&sdata=DKoDYJZ5D%2B%2FuJMQBLilTI%2Bv3%2FbP9PJFxu2ABN9m%2FsDA%3D&reserved=0)
>         Panbiogeography: Tracking the history of life. Oxford University
> Press,
> New York. 1999. (With R. Craw and J. Grehan).
> https://nam10.safelinks.protection.outlook.com/?url=http%3A%2F%2Fbooks.google.co.nz%2Fbooks%3Fid%3DBm0_QQ3Z6GUC&data%7C02%7Ctaxacom%40lists.ku.edu%7C257f32bac53a4bdaa37708dd692be6a1%7C3c176536afe643f5b96636feabbe3c1a%7C0%7C0%7C638782359905728587%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C60000%7C%7C%7C&sdata=vCa5WpJ1qhqCCrb8bhb1nOViaiXNmKQN%2BPttKquRpAw%3D&reserved=0
> (
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>
>
> _______________________________________________
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-- 
Dunedin, New Zealand.

My books:

*Biogeography and evolution in New Zealand. *Taylor and Francis/CRC, Boca
Raton FL. 2017.
https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.routledge.com%2FBiogeography-and-Evolution-in-New-Zealand%2FHeads%2Fp%2Fbook%2F9781498751872&data%7C02%7Ctaxacom%40lists.ku.edu%7C257f32bac53a4bdaa37708dd692be6a1%7C3c176536afe643f5b96636feabbe3c1a%7C0%7C0%7C638782359905751316%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C60000%7C%7C%7C&sdata=zoWgRzHCH6wLH3sOm0LFdtsebcQcdOhkJueDtkul3A0%3D&reserved=0


*Biogeography of Australasia:  A molecular analysis*. Cambridge University
Press, Cambridge. 2014. https://nam10.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.cambridge.org%2F9781107041028&data%7C02%7Ctaxacom%40lists.ku.edu%7C257f32bac53a4bdaa37708dd692be6a1%7C3c176536afe643f5b96636feabbe3c1a%7C0%7C0%7C638782359905763070%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C60000%7C%7C%7C&sdataÞ9XKsqpCYWRsZBJu1WBGH3g8yCWN9UdgbQdgqN%2BaPY%3D&reserved=0


*Molecular panbiogeography of the tropics. *University of California Press,
Berkeley. 2012. https://nam10.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.ucpress.edu%2Fbook.php%3Fisbn%3D9780520271968&data%7C02%7Ctaxacom%40lists.ku.edu%7C257f32bac53a4bdaa37708dd692be6a1%7C3c176536afe643f5b96636feabbe3c1a%7C0%7C0%7C638782359905775456%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C60000%7C%7C%7C&sdata=nWfkAetk7WDYTpBDabYcWFiLdtStHipYKfiRPKbgHXU%3D&reserved=0


*Panbiogeography: Tracking the history of life*. Oxford University Press,
New York. 1999. (With R. Craw and J. Grehan).
https://nam10.safelinks.protection.outlook.com/?url=http%3A%2F%2Fbooks.google.co.nz%2Fbooks%3Fid%3DBm0_QQ3Z6GUC&data%7C02%7Ctaxacom%40lists.ku.edu%7C257f32bac53a4bdaa37708dd692be6a1%7C3c176536afe643f5b96636feabbe3c1a%7C0%7C0%7C638782359905787981%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C60000%7C%7C%7C&sdata=eI9FRig0FUlH38rX5%2FzHV8id6MEy865c5K%2B2vJiAq%2FE%3D&reserved=0
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