[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Dinosaur "fleas" misidentified? (free pdf)



I had the exact same impression as Mickey.  Dittmar et al.'s critique
is largely typological:  Fleas have characters A, B and C.  Gao et
al's "wingless invertebrates" do not have A, B and C.  Ergo, they
cannot be fleas (neither stem fleas or crown fleas).  Never mind that
characters A, B and C diagnose *extant* fleas, and their stem
relatives may not have gotten around to evolving these particular
characters yet.  (At the time, they were doing quite well without
these characters.)  Additionally, stem fleas may also have evolved
characters J, K and L that never arose in the crown group.  Again,
this shouldn't be a surprise.

Nor were stem fleas obliged to go extinct once the crown group arrived
on the scene.  This is a curious interpretation of Dittmar &c, who
seem perplexed at the prospect that "extant siphonapteran lineages...
would then overlap in age with the morphologically very distinct
Cretaceous fossils".  In fact, a whole bunch of diverse stem flea taxa
undoubtedly lived at the same time as the first members of crown
Siphonaptera (= extant flea lineages), each species with its own niche
(or host).  In today's world, cockroaches co-exist with termites - and
the former are paraphyletic relative to the latter.




On Wed, Jan 13, 2016 at 3:16 PM, Mickey Mortimer
<mickey_mortimer111@msn.com> wrote:
> Gotta say that Gao et al.'s response to Dittmar et al.'s criticisms seems 
> valid.  I'm no entomologist, but Dittmar et al. sound like BANDits when they 
> say the fossils differ from crown fleas (with no alternative identification 
> proposed) and state that each proposed flea-like character is individually 
> found in other insects without considering the character evidence as a whole.
>
> Mickey Mortimer
>
> ----------------------------------------
>> Date: Tue, 12 Jan 2016 19:53:37 -0800
>> From: bcreisler@gmail.com
>> To: dinosaur@usc.edu
>> Subject: Dinosaur "fleas" misidentified? (free pdf)
>>
>> Ben Creisler
>> bcreisler@gmail.com
>>
>> A new paper in open access:
>>
>> Katharina Dittmar , Qiyun Zhu, Michael W. Hastriter & Michael F. Whiting 
>> (2016)
>> On the probability of dinosaur fleas.
>> BMC Evolutionary Biology (advance online publication)
>> DOI: 10.1186/s12862-015-0568-x
>> http://link.springer.com/article/10.1186/s12862-015-0568-x
>>
>> Recently, a set of publications described flea fossils from Jurassic
>> and Early Cretaceous geological strata in northeastern China, which
>> were suggested to have parasitized feathered dinosaurs, pterosaurs,
>> and early birds or mammals. In support of these fossils being fleas, a
>> recent publication in BMC Evolutionary Biology described the extended
>> abdomen of a female fossil specimen as due to blood feeding.
>>
>> We here comment on these findings, and conclude that the current
>> interpretation of the evolutionary trajectory and ecology of these
>> putative dinosaur fleas is based on appeal to probability, rather than
>> evidence. Hence, their taxonomic positioning as fleas, or stem fleas,
>> as well as their ecological classification as ectoparasites and blood
>> feeders is not supported by currently available data.
>