Re: [dinosaur] How many end-Cretaceous dinosaur genera were there

[Thomas Richard Holtz <tholtz@umd.edu>]

Consider that the VAST majority of these bird species are concentrated on a few clades (like passerines) of relatively recent origin. Clades of organisms aren't required to have the same diversity in each branch.

Furthermore, with much greater ontogenetic size spread than either typical large placental mammals or typical avians, non-avialian dinosaurs ecological were potentially equivalent to multiple species of large mammal today.

All that said, the answer to Poekilopleuron's answer is "we don't know". But for a rough approximation, take the Hell Creek fauna (by FAR the best studied terminal Maastrichtian fauna) and then multiply if a few times: for the European archipelago, for eastern and central Asia, for India, for Australasia, for Madagascar, for continental Africa, for South America. This number would probably be within an order of magnitude of truth.

On Sun, Dec 4, 2016 at 2:00 AM, Mike Habib <biologyinmotion@gmail.com> wrote:

Correction: Obviously I meant “Of those 5,416 species of mammals, about 75% of them are a rodent or a bat”. Sorry for the ridiculous typo.

—Mike


Michael Habib, MS, PhD
Assistant Professor, Cell and Neurobiology
Keck School of Medicine of USC
University of Southern California
Bishop Research Building; Room 403
1333 San Pablo Street, Los Angeles 90089-9112

Research Associate, Dinosaur Institute
Natural History Museum of Los Angeles County
900 Exposition Blvd, Los Angeles, CA 90007

biologyinmotion@gmail.com
(443) 280-0181

> On Dec 3, 2016, at 10:53 PM, Mike Habib <biologyinmotion@gmail.com> wrote:
>
> Of those 5,416 species of mammals, about 75% of them are a bird or bat, i.e. small bodied animals that don’t have particularly good parallels among non-avian dinosaurs. The best cross-comparison to those taxa among dinosaurs would be the small-bodied dinosaur radiation (paravians, of which most are birds). My understanding is that the Jean Le Loeuff estimate is for non-avian dinosaurs, only (though I’ll have to check). If that is the case, then a better rough comparison would probably be with the 25% of mammals that are not rodents or bats (which is still a bit dodgy, because many of them are other small bodied things like Eulipotyphlans etc).
>
> So, being generous, that’s about 1,354 species of mammals that are roughly cross-comparable (assuming we think living mammal diversity is a good guide to expected dinosaur diversity, which it might not be). That is moderately, but not exceptionally, outside the maximum dinosaur species estimate from Le Loeuff (which, of course, should be taken to have significant error margins on it).
>
> Species diversity estimates for dinosaurs are typically not based on an assumption that we have a complete (or even near complete) sampling of faunas, but rather on specific models of how incomplete the sample is likely to be. The Le Loeuff model may be on the conservative end of that spectrum.
>
> —Mike
>
>
> Michael Habib, MS, PhD
> Assistant Professor, Cell and Neurobiology
> Keck School of Medicine of USC
> University of Southern California
> Bishop Research Building; Room 403
> 1333 San Pablo Street, Los Angeles 90089-9112
>
> Research Associate, Dinosaur Institute
> Natural History Museum of Los Angeles County
> 900 Exposition Blvd, Los Angeles, CA 90007
>
> biologyinmotion@gmail.com
> (443) 280-0181
>
>
>
>
>
>
>> On Dec 3, 2016, at 9:21 PM, Ruben Safir <ruben@mrbrklyn.com> wrote:
>
>> According to Mammal Species of the World, 5,416 species were known in
>> 2006. These were grouped in 1,229 genera, 153 families and 29 orders
>>
>> from wikipedia...
>>
>> and I bet that is a severe underestimate of the number of mammal species
>> alive today.
>>
>> I have no idea how they get 628 to 1076 but if it is based on the
>> thought that we have anything near a complete image of the fauna from 70
>> million years ago (after a comet smashed a huge hole into the earths
>> crust the size of the midwest), then I think you need to reconsider.
>>
>> and who said birds weren't to count as dinosaurs.  think about how many
>> species were discovered just since you have entered the field.  And you
>> have lost whole continents.
>>
>>
>>>
>>>> --Mike
>>>>
>>>> Sent from my Cybernetic Symbiote
>>>>
>>>>> On Dec 3, 2016, at 7:18 PM, Ruben Safir <ruben@mrbrklyn.com> wrote:
>>>>>
>>>>>> On 12/03/2016 10:12 PM, john-schneiderman@cox.net wrote:
>>>>>> I am not aware of any current world-wide census of terminal late Cretaceous Dinosaur genus/species. But there is an estimate of between 628 and 1076 dinosaur species existed prior to the K-Pg event. I'm referencing the study by Jean Le Loeuff
>>>>>
>>>>>
>>>>> Does that make sense?  How many bird species are there today?
>>>>>
>>
>>
>> --
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>>
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>

--

Thomas R. Holtz, Jr.
Email: tholtz@umd.edu         Phone: 301-405-4084
Principal Lecturer, Vertebrate Paleontology

Office: Geology 4106, 8000 Regents Dr., College Park MD 20742

Dept. of Geology, University of Maryland
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