ID challenge_02 #glossary


scitech200
 

A new image has now been added to the Monthly ID Challenge folder.

It's another larger centric specimen with distinctive features - 5x protuberances toward the perimeter. It has a domed central region and the focal plane has been selected to show as many different features as possible.
There are at least 5 specimens of this taxon on the ex Chappell slide, with diamaters varying by 10-15%. The largest of these is broken, but it seems to clearly show the distinctive feature as being a protuberance (process?), not a horn (spike).

The next image (ID_03) will be for one of "horned" variety on the same slide.

Enjoy,
Keith


Charles Suslavage
 

Hi Keith,
Your new centric fossil diatom challenge with the five 'protuberances', or processes, rimoportula, is probably genus Aulacodiscus. Species ID, at least for me will require detailed image of central area and outer edge.
Charles

--- In diatom_forum@..., "Keith Shaw" <scitech200@...> wrote:

A new image has now been added to the Monthly ID Challenge folder.

It's another larger centric specimen with distinctive features - 5x protuberances toward the perimeter. It has a domed central region and the focal plane has been selected to show as many different features as possible.
There are at least 5 specimens of this taxon on the ex Chappell slide, with diamaters varying by 10-15%. The largest of these is broken, but it seems to clearly show the distinctive feature as being a protuberance (process?), not a horn (spike).

The next image (ID_03) will be for one of "horned" variety on the same slide.

Enjoy,
Keith


Richard Carter
 

Keith,

Welcome back, you have been sorely missed!

Glad to see that you are continuing the monthly ID challenge, too.  And I am certainly looking forward to hearing more about the Kingfisher Pond studies, also.

I'm going to be doing Toome Bridge stuff for a while, but will be returning to Cherryfieldish stuff eventually.

And I'm trying to get slides made to send to you, and about five other people as well.  It proceeds slowly............

Warmest regards,

Dick


From: Keith Shaw
To: diatom_forum@...
Sent: Saturday, August 4, 2012 12:18 PM
Subject: [diatom_forum] ID challenge_02

 
A new image has now been added to the Monthly ID Challenge folder.

It's another larger centric specimen with distinctive features - 5x protuberances toward the perimeter. It has a domed central region and the focal plane has been selected to show as many different features as possible.
There are at least 5 specimens of this taxon on the ex Chappell slide, with diamaters varying by 10-15%. The largest of these is broken, but it seems to clearly show the distinctive feature as being a protuberance (process?), not a horn (spike).

The next image (ID_03) will be for one of "horned" variety on the same slide.

Enjoy,
Keith




scitech200
 

Charles,

Hey thanks for the prelim ID. I expect that you are right on track...

I had another image for a higher focal plane, for the same specimen, and it's now posted as ID_02.2 for your inspection.

I'll find the time tomorrow to try for better images, do a proper focal plane sequence and then a stacked image.

Best,
Keith


"charles" wrote:

Hi Keith,
Your new centric fossil diatom challenge with the five 'protuberances', or processes, rimoportula, is probably genus Aulacodiscus. Species ID, at least for me will require detailed image of central area and outer edge.
Charles


scitech200
 

Dick,

It's frustrating at times not being able to really focus (ha, ha) on some microscopy projects.

...but will be returning to Cherryfieldish stuff eventually.
Me too.
In the meantime I have some Pinnularia specimens from a local pond that I think may come close to matching the size of those big boys from Chalk Pond.

Also, the "Cherryfield diatoms" puzzle may continue for a bit.
I'm setting up for another field trip with my friend Jack and we are going to check out a specific pond not far from Cherryfield. It's close by the very deep pond that had the great distribution of desmid species. Hint: I'm intriqued by the locals referring to the Chalk Pond diatomite as "silica".

More later,
Keith



Richard Carter wrote:
Keith,
Welcome back, you have been sorely missed!
Glad to see that you are continuing the monthly ID challenge, too.  And I am certainly looking forward to hearing more about the Kingfisher Pond studies, also.

I'm going to be doing Toome Bridge stuff for a while, but will be returning to Cherryfieldish stuff eventually.

And I'm trying to get slides made to send to you, and about five other people as well.  It proceeds slowly............

Warmest regards,
Dick


klaus.kemp <klaus.kemp@...>
 

Keith,
I think this might be Aulacodiscus rogersii (Bailey) A. Schmidt, but will see what others think. Can you tell me where the location is?
Klaus

--- In diatom_forum@..., "Keith Shaw" <scitech200@...> wrote:

Dick,

It's frustrating at times not being able to really focus (ha, ha) on some microscopy projects.

...but will be returning to Cherryfieldish stuff eventually.
Me too.
In the meantime I have some Pinnularia specimens from a local pond that I think may come close to matching the size of those big boys from Chalk Pond.

Also, the "Cherryfield diatoms" puzzle may continue for a bit.
I'm setting up for another field trip with my friend Jack and we are going to check out a specific pond not far from Cherryfield. It's close by the very deep pond that had the great distribution of desmid species. Hint: I'm intriqued by the locals referring to the Chalk Pond diatomite as "silica".

More later,
Keith



Richard Carter wrote:
Keith,
Welcome back, you have been sorely missed!
Glad to see that you are continuing the monthly ID challenge, too.  And I am certainly looking forward to hearing more about the Kingfisher Pond studies, also.

I'm going to be doing Toome Bridge stuff for a while, but will be returning to Cherryfieldish stuff eventually.

And I'm trying to get slides made to send to you, and about five other people as well.  It proceeds slowly............

Warmest regards,
Dick


scitech200
 

Klaus,

I do not know the location.
This is one of the strew slides within the ex Chappell collection that has no label! However, it's a nice clean strew slide - just like those we have come to enjoy from a certain gentleman in the UK...
Dave Richman has talked recently with folks at the ANSP and evidently they think that Cyrus Chappell may have been mounting slides for Charles Boyer. This is an interesting possibility, given the unlabeled slides and hand written notes/diagrams.

I expect that the fossil specimens are of Miocene vintage. It could also be from a marine environment, based upon a single Triceratium sp. that has shown up...
Hopefully, as we ID additional specimens from this slide we'll be able to narrow down possible locations.

As always, thank you for your assistance.

Best regards,
Keith


"klaus.kemp" wrote:

Keith,
I think this might be Aulacodiscus rogersii (Bailey) A. Schmidt, but will see what others think. Can you tell me where the location is?
Klaus


Richard Carter
 

I would agree, Klaus.  For those interested, there are some excellent SEM images of this taxon in the set that Bill Dailey has made available on his website.  There are hyperlinks in my file entitled "Dunkirk Diatoms".

Dick


From: klaus.kemp
To: diatom_forum@...
Sent: Sunday, August 5, 2012 5:57 AM
Subject: [diatom_forum] Re: ID challenge_02

Keith,
I think this might be Aulacodiscus rogersii (Bailey) A. Schmidt, but will see what others think. Can you tell me where the location is?
Klaus


Charles Suslavage
 

Hello Keith,

I made a quick search through my Miocene collection, not extensive enough I’m afraid, and found one similar, five rimoportula, from a slide labeled Nottingham Maryland.

Charles




From: Keith Shaw
To: diatom_forum@...
Sent: Sun, August 5, 2012 6:30:19 AM
Subject: [diatom_forum] Re: ID challenge_02

 

Klaus,

I do not know the location.
This is one of the strew slides within the ex Chappell collection that has no label! However, it's a nice clean strew slide - just like those we have come to enjoy from a certain gentleman in the UK...
Dave Richman has talked recently with folks at the ANSP and evidently they think that Cyrus Chappell may have been mounting slides for Charles Boyer. This is an interesting possibility, given the unlabeled slides and hand written notes/diagrams.

I expect that the fossil specimens are of Miocene vintage. It could also be from a marine environment, based upon a single Triceratium sp. that has shown up...
Hopefully, as we ID additional specimens from this slide we'll be able to narrow down possible locations.

As always, thank you for your assistance.

Best regards,
Keith

"klaus.kemp" wrote:
> Keith,
> I think this might be Aulacodiscus rogersii (Bailey) A. Schmidt, but will see what others think. Can you tell me where the location is?
> Klaus


Richard Carter
 

Charles,

I think it's a good bet that the sample on this unlabeled slide is of Miocene age, and that it was from the east coast of the US.  I have specimens of this taxon from Dunkirk and "Patuxent River", Maryland, and from the Kirkwood Formation at Atlantic City, New Jersey.

Dick


From: charles suslavage
To: diatom_forum@...
Sent: Sunday, August 5, 2012 7:27 AM
Subject: Re: [diatom_forum] Re: ID challenge_02

 
Hello Keith,
I made a quick search through my Miocene collection, not extensive enough I’m afraid, and found one similar, five rimoportula, from a slide labeled Nottingham Maryland.
Charles



From: Keith Shaw
To: diatom_forum@...
Sent: Sun, August 5, 2012 6:30:19 AM
Subject: [diatom_forum] Re: ID challenge_02

 
Klaus,

I do not know the location.
This is one of the strew slides within the ex Chappell collection that has no label! However, it's a nice clean strew slide - just like those we have come to enjoy from a certain gentleman in the UK...
Dave Richman has talked recently with folks at the ANSP and evidently they think that Cyrus Chappell may have been mounting slides for Charles Boyer. This is an interesting possibility, given the unlabeled slides and hand written notes/diagrams.

I expect that the fossil specimens are of Miocene vintage. It could also be from a marine environment, based upon a single Triceratium sp. that has shown up...
Hopefully, as we ID additional specimens from this slide we'll be able to narrow down possible locations.

As always, thank you for your assistance.

Best regards,
Keith

"klaus.kemp" wrote:
> Keith,
> I think this might be Aulacodiscus rogersii (Bailey) A. Schmidt, but will see what others think. Can you tell me where the location is?
> Klaus




Charles Suslavage
 

Hi Dick,

In this instance are you using ‘taxon’ to indicate genus or species? I have several different species of Aulacodiscus from Miocene deposits on both the east and west coast but the only location having one similar Aulacodiscus was Nottingham. I am pretty sure your usage is not related to a Clade (chuckle chuckle).

Charles




From: Richard Carter
To: "diatom_forum@..."
Sent: Sun, August 5, 2012 7:48:30 AM
Subject: Re: [diatom_forum] Re: ID challenge_02

 

Charles,

I think it's a good bet that the sample on this unlabeled slide is of Miocene age, and that it was from the east coast of the US.  I have specimens of this taxon from Dunkirk and "Patuxent River", Maryland, and from the Kirkwood Formation at Atlantic City, New Jersey.

Dick


From: charles suslavage
To: diatom_forum@...
Sent: Sunday, August 5, 2012 7:27 AM
Subject: Re: [diatom_forum] Re: ID challenge_02

 
Hello Keith,
I made a quick search through my Miocene collection, not extensive enough I’m afraid, and found one similar, five rimoportula, from a slide labeled Nottingham Maryland.
Charles



From: Keith Shaw
To: diatom_forum@...
Sent: Sun, August 5, 2012 6:30:19 AM
Subject: [diatom_forum] Re: ID challenge_02

 
Klaus,

I do not know the location.
This is one of the strew slides within the ex Chappell collection that has no label! However, it's a nice clean strew slide - just like those we have come to enjoy from a certain gentleman in the UK...
Dave Richman has talked recently with folks at the ANSP and evidently they think that Cyrus Chappell may have been mounting slides for Charles Boyer. This is an interesting possibility, given the unlabeled slides and hand written notes/diagrams.

I expect that the fossil specimens are of Miocene vintage. It could also be from a marine environment, based upon a single Triceratium sp. that has shown up...
Hopefully, as we ID additional specimens from this slide we'll be able to narrow down possible locations.

As always, thank you for your assistance.

Best regards,
Keith

"klaus.kemp" wrote:
> Keith,
> I think this might be Aulacodiscus rogersii (Bailey) A. Schmidt, but will see what others think. Can you tell me where the location is?
> Klaus




Richard Carter
 

Charles,

I use the term to mean essentially "a taxonomic unit, either species or variety."  I don't know if it can also be used for units at higher levels, e.g. a genus.  So my intended sense was "the taxonomic unit illustrated in Keith's photo," whether we can name it or not.  And I have seen no records of this taxon from the west coast, nor do I know if it occurs in the Miocene of Europe.  Certainly a beautiful diatom!

Dick


From: charles suslavage
To: diatom_forum@...
Sent: Sunday, August 5, 2012 1:28 PM
Subject: Re: [diatom_forum] Re: ID challenge_02

 
Hi Dick,
In this instance are you using ‘taxon’ to indicate genus or species? I have several different species of Aulacodiscus from Miocene deposits on both the east and west coast but the only location having one similar Aulacodiscus was Nottingham. I am pretty sure your usage is not related to a Clade (chuckle chuckle).
Charles



From: Richard Carter
To: "diatom_forum@..."
Sent: Sun, August 5, 2012 7:48:30 AM
Subject: Re: [diatom_forum] Re: ID challenge_02

 
Charles,

I think it's a good bet that the sample on this unlabeled slide is of Miocene age, and that it was from the east coast of the US.  I have specimens of this taxon from Dunkirk and "Patuxent River", Maryland, and from the Kirkwood Formation at Atlantic City, New Jersey.

Dick


From: charles suslavage
To: diatom_forum@...
Sent: Sunday, August 5, 2012 7:27 AM
Subject: Re: [diatom_forum] Re: ID challenge_02

 
Hello Keith,
I made a quick search through my Miocene collection, not extensive enough I’m afraid, and found one similar, five rimoportula, from a slide labeled Nottingham Maryland.
Charles



From: Keith Shaw
To: diatom_forum@...
Sent: Sun, August 5, 2012 6:30:19 AM
Subject: [diatom_forum] Re: ID challenge_02

 
Klaus,

I do not know the location.
This is one of the strew slides within the ex Chappell collection that has no label! However, it's a nice clean strew slide - just like those we have come to enjoy from a certain gentleman in the UK...
Dave Richman has talked recently with folks at the ANSP and evidently they think that Cyrus Chappell may have been mounting slides for Charles Boyer. This is an interesting possibility, given the unlabeled slides and hand written notes/diagrams.

I expect that the fossil specimens are of Miocene vintage. It could also be from a marine environment, based upon a single Triceratium sp. that has shown up...
Hopefully, as we ID additional specimens from this slide we'll be able to narrow down possible locations.

As always, thank you for your assistance.

Best regards,
Keith

"klaus.kemp" wrote:
> Keith,
> I think this might be Aulacodiscus rogersii (Bailey) A. Schmidt, but will see what others think. Can you tell me where the location is?
> Klaus






Charles Suslavage
 

Hi Dick,

I’m not much of a word smith so I do get confused easily.

The Glossary of the International Code of Zoological Nomenclature (1999) defines “taxon, (pl. taxa), n. A taxonomic unit, whether named or not: i.e. a population, or group of populations of organisms which are usually inferred to be phylogenetically related and which have characters in common which differentiate (q.v.) the unit (e.g. a geographic population, a genus, a family, an order) from other such units. A taxon encompasses all included taxa of lower rank (q.v.) and individual organisms. [...]"

When not sure about a word or how it is being used I look it up and your emails frequently send me on a search. the above definition is only one and it seems taxonomists are not in uniform agreement on its usage.

Charles




From: Richard Carter
To: "diatom_forum@..."
Sent: Sun, August 5, 2012 2:25:23 PM
Subject: Re: [diatom_forum] Re: ID challenge_02

 

Charles,

I use the term to mean essentially "a taxonomic unit, either species or variety."  I don't know if it can also be used for units at higher levels, e.g. a genus.  So my intended sense was "the taxonomic unit illustrated in Keith's photo," whether we can name it or not.  And I have seen no records of this taxon from the west coast, nor do I know if it occurs in the Miocene of Europe.  Certainly a beautiful diatom!

Dick


From: charles suslavage
To: diatom_forum@...
Sent: Sunday, August 5, 2012 1:28 PM
Subject: Re: [diatom_forum] Re: ID challenge_02

 
Hi Dick,
In this instance are you using ‘taxon’ to indicate genus or species? I have several different species of Aulacodiscus from Miocene deposits on both the east and west coast but the only location having one similar Aulacodiscus was Nottingham. I am pretty sure your usage is not related to a Clade (chuckle chuckle).
Charles



From: Richard Carter
To: "diatom_forum@..."
Sent: Sun, August 5, 2012 7:48:30 AM
Subject: Re: [diatom_forum] Re: ID challenge_02

 
Charles,

I think it's a good bet that the sample on this unlabeled slide is of Miocene age, and that it was from the east coast of the US.  I have specimens of this taxon from Dunkirk and "Patuxent River", Maryland, and from the Kirkwood Formation at Atlantic City, New Jersey.

Dick


From: charles suslavage
To: diatom_forum@...
Sent: Sunday, August 5, 2012 7:27 AM
Subject: Re: [diatom_forum] Re: ID challenge_02

 
Hello Keith,
I made a quick search through my Miocene collection, not extensive enough I’m afraid, and found one similar, five rimoportula, from a slide labeled Nottingham Maryland.
Charles



From: Keith Shaw
To: diatom_forum@...
Sent: Sun, August 5, 2012 6:30:19 AM
Subject: [diatom_forum] Re: ID challenge_02

 
Klaus,

I do not know the location.
This is one of the strew slides within the ex Chappell collection that has no label! However, it's a nice clean strew slide - just like those we have come to enjoy from a certain gentleman in the UK...
Dave Richman has talked recently with folks at the ANSP and evidently they think that Cyrus Chappell may have been mounting slides for Charles Boyer. This is an interesting possibility, given the unlabeled slides and hand written notes/diagrams.

I expect that the fossil specimens are of Miocene vintage. It could also be from a marine environment, based upon a single Triceratium sp. that has shown up...
Hopefully, as we ID additional specimens from this slide we'll be able to narrow down possible locations.

As always, thank you for your assistance.

Best regards,
Keith

"klaus.kemp" wrote:
> Keith,
> I think this might be Aulacodiscus rogersii (Bailey) A. Schmidt, but will see what others think. Can you tell me where the location is?
> Klaus






Richard Carter
 

Charles,

Thanks for this!  The first part of the definition certainly covers the way I use it, but it's good to know that it can be used at any taxonomic rank -- I was not sure about that.

Dick


From: charles suslavage
To: diatom_forum@...
Sent: Sunday, August 5, 2012 4:03 PM
Subject: Re: [diatom_forum] Re: ID challenge_02

 
Hi Dick,
I’m not much of a word smith so I do get confused easily.
The Glossary of the International Code of Zoological Nomenclature (1999) defines “taxon, (pl. taxa), n. A taxonomic unit, whether named or not: i.e. a population, or group of populations of organisms which are usually inferred to be phylogenetically related and which have characters in common which differentiate (q.v.) the unit (e.g. a geographic population, a genus, a family, an order) from other such units. A taxon encompasses all included taxa of lower rank (q.v.) and individual organisms. [...]"
When not sure about a word or how it is being used I look it up and your emails frequently send me on a search. the above definition is only one and it seems taxonomists are not in uniform agreement on its usage.
Charles



From: Richard Carter
To: "diatom_forum@..."
Sent: Sun, August 5, 2012 2:25:23 PM
Subject: Re: [diatom_forum] Re: ID challenge_02

 
Charles,

I use the term to mean essentially "a taxonomic unit, either species or variety."  I don't know if it can also be used for units at higher levels, e.g. a genus.  So my intended sense was "the taxonomic unit illustrated in Keith's photo," whether we can name it or not.  And I have seen no records of this taxon from the west coast, nor do I know if it occurs in the Miocene of Europe.  Certainly a beautiful diatom!

Dick


From: charles suslavage
To: diatom_forum@...
Sent: Sunday, August 5, 2012 1:28 PM
Subject: Re: [diatom_forum] Re: ID challenge_02

 
Hi Dick,
In this instance are you using ‘taxon’ to indicate genus or species? I have several different species of Aulacodiscus from Miocene deposits on both the east and west coast but the only location having one similar Aulacodiscus was Nottingham. I am pretty sure your usage is not related to a Clade (chuckle chuckle).
Charles



From: Richard Carter
To: "diatom_forum@..."
Sent: Sun, August 5, 2012 7:48:30 AM
Subject: Re: [diatom_forum] Re: ID challenge_02

 
Charles,

I think it's a good bet that the sample on this unlabeled slide is of Miocene age, and that it was from the east coast of the US.  I have specimens of this taxon from Dunkirk and "Patuxent River", Maryland, and from the Kirkwood Formation at Atlantic City, New Jersey.

Dick


From: charles suslavage
To: diatom_forum@...
Sent: Sunday, August 5, 2012 7:27 AM
Subject: Re: [diatom_forum] Re: ID challenge_02

 
Hello Keith,
I made a quick search through my Miocene collection, not extensive enough I’m afraid, and found one similar, five rimoportula, from a slide labeled Nottingham Maryland.
Charles



From: Keith Shaw
To: diatom_forum@...
Sent: Sun, August 5, 2012 6:30:19 AM
Subject: [diatom_forum] Re: ID challenge_02

 
Klaus,

I do not know the location.
This is one of the strew slides within the ex Chappell collection that has no label! However, it's a nice clean strew slide - just like those we have come to enjoy from a certain gentleman in the UK...
Dave Richman has talked recently with folks at the ANSP and evidently they think that Cyrus Chappell may have been mounting slides for Charles Boyer. This is an interesting possibility, given the unlabeled slides and hand written notes/diagrams.

I expect that the fossil specimens are of Miocene vintage. It could also be from a marine environment, based upon a single Triceratium sp. that has shown up...
Hopefully, as we ID additional specimens from this slide we'll be able to narrow down possible locations.

As always, thank you for your assistance.

Best regards,
Keith

"klaus.kemp" wrote:
> Keith,
> I think this might be Aulacodiscus rogersii (Bailey) A. Schmidt, but will see what others think. Can you tell me where the location is?
> Klaus








Charles Suslavage
 

Hi Dick,

Once again I’ve learned a tad more. This forum is very enjoyable and it will be good when I can once again devote more time.

Charles



From: Richard Carter
To: "diatom_forum@..."
Sent: Sun, August 5, 2012 5:51:49 PM
Subject: Re: [diatom_forum] Re: ID challenge_02

 

Charles,

Thanks for this!  The first part of the definition certainly covers the way I use it, but it's good to know that it can be used at any taxonomic rank -- I was not sure about that.

Dick


From: charles suslavage
To: diatom_forum@...
Sent: Sunday, August 5, 2012 4:03 PM
Subject: Re: [diatom_forum] Re: ID challenge_02

 
Hi Dick,
I’m not much of a word smith so I do get confused easily.
The Glossary of the International Code of Zoological Nomenclature (1999) defines “taxon, (pl. taxa), n. A taxonomic unit, whether named or not: i.e. a population, or group of populations of organisms which are usually inferred to be phylogenetically related and which have characters in common which differentiate (q.v.) the unit (e.g. a geographic population, a genus, a family, an order) from other such units. A taxon encompasses all included taxa of lower rank (q.v.) and individual organisms. [...]"
When not sure about a word or how it is being used I look it up and your emails frequently send me on a search. the above definition is only one and it seems taxonomists are not in uniform agreement on its usage.
Charles



From: Richard Carter
To: "diatom_forum@..."
Sent: Sun, August 5, 2012 2:25:23 PM
Subject: Re: [diatom_forum] Re: ID challenge_02

 
Charles,

I use the term to mean essentially "a taxonomic unit, either species or variety."  I don't know if it can also be used for units at higher levels, e.g. a genus.  So my intended sense was "the taxonomic unit illustrated in Keith's photo," whether we can name it or not.  And I have seen no records of this taxon from the west coast, nor do I know if it occurs in the Miocene of Europe.  Certainly a beautiful diatom!

Dick


From: charles suslavage
To: diatom_forum@...
Sent: Sunday, August 5, 2012 1:28 PM
Subject: Re: [diatom_forum] Re: ID challenge_02

 
Hi Dick,
In this instance are you using ‘taxon’ to indicate genus or species? I have several different species of Aulacodiscus from Miocene deposits on both the east and west coast but the only location having one similar Aulacodiscus was Nottingham. I am pretty sure your usage is not related to a Clade (chuckle chuckle).
Charles



From: Richard Carter
To: "diatom_forum@..."
Sent: Sun, August 5, 2012 7:48:30 AM
Subject: Re: [diatom_forum] Re: ID challenge_02

 
Charles,

I think it's a good bet that the sample on this unlabeled slide is of Miocene age, and that it was from the east coast of the US.  I have specimens of this taxon from Dunkirk and "Patuxent River", Maryland, and from the Kirkwood Formation at Atlantic City, New Jersey.

Dick


From: charles suslavage
To: diatom_forum@...
Sent: Sunday, August 5, 2012 7:27 AM
Subject: Re: [diatom_forum] Re: ID challenge_02

 
Hello Keith,
I made a quick search through my Miocene collection, not extensive enough I’m afraid, and found one similar, five rimoportula, from a slide labeled Nottingham Maryland.
Charles



From: Keith Shaw
To: diatom_forum@...
Sent: Sun, August 5, 2012 6:30:19 AM
Subject: [diatom_forum] Re: ID challenge_02

 
Klaus,

I do not know the location.
This is one of the strew slides within the ex Chappell collection that has no label! However, it's a nice clean strew slide - just like those we have come to enjoy from a certain gentleman in the UK...
Dave Richman has talked recently with folks at the ANSP and evidently they think that Cyrus Chappell may have been mounting slides for Charles Boyer. This is an interesting possibility, given the unlabeled slides and hand written notes/diagrams.

I expect that the fossil specimens are of Miocene vintage. It could also be from a marine environment, based upon a single Triceratium sp. that has shown up...
Hopefully, as we ID additional specimens from this slide we'll be able to narrow down possible locations.

As always, thank you for your assistance.

Best regards,
Keith

"klaus.kemp" wrote:
> Keith,
> I think this might be Aulacodiscus rogersii (Bailey) A. Schmidt, but will see what others think. Can you tell me where the location is?
> Klaus








klaus.kemp <klaus.kemp@...>
 

Dick,
It seems you should be congratulated for your excellent idea of creating a Toome Bridge image database. I have to say that it has caused me to be able to dig out some of the slide I have made with the only identification being to Genus, now I am a little wiser. This is an area that Bernard Hartley was keen for me to come to grips with and I miss his mentoring. Regarding your Pinnularia H I would have placed it in Pinnularia brevicostata Cleve, so now it is your turn to mentor me, what have I missed in my naming?
Klaus

--- In diatom_forum@..., Richard Carter <rcarter68502@...> wrote:

I would agree, Klaus.  For those interested, there are some excellent SEM images of this taxon in the set that Bill Dailey has made available on his website.  There are hyperlinks in my file entitled "Dunkirk Diatoms".

Dick



________________________________
From: klaus.kemp <klaus.kemp@...>
To: diatom_forum@...
Sent: Sunday, August 5, 2012 5:57 AM
Subject: [diatom_forum] Re: ID challenge_02

Keith,
I think this might be Aulacodiscus rogersii (Bailey) A. Schmidt, but will see what others think. Can you tell me where the location is?
Klaus


Richard Carter
 

Klaus,

Thanks for your comment on the Toome Bridge images.  Most of them are just quick "snapshots", that I make for measurements.  And I regret that some are a bit dark -- I have yet to learn how to cut down the contrast in my camera, and can only manage "hot spots" by lowering the exposure.  Must get out the instruction manual again..........!

Pinnularia sp. H is one of several taxa that I have been unable to identify.  (When I post the next version of the Toome Bridge floral list, I'll be adding notes for each of these.)  First, the pronounced "ground glass spots" in the central area clearly mark this taxon as belonging to the gibba-complex, most of which have this pattern of four spots, two larger on the ventral side, two smaller on the dorsal side.  P. brevicostata is not a member of this complex, and shows no trace (at least in Krammer's photographs) of such markings.  (SEM images show that the spots are produced by a thinning of the silica on the valve interior.)  P. brevicostata occasionally shows a missing stria on one side, but never has a fascia.  And the morphometrics don't match: Krammer lists length 80-150 µm., breadth 19-22 µm., and striae 6-7/10 µm.  Pinnularia sp. H (my designation) is rather smaller; the specimen I illustrated is the largest I have yet seen at length 92 µm., breadth 12 µm., striae 9/10 µm.  Since valve breadth is the most consistent of the usual measurements, the fact that my largest specimen falls well below Krammer's minimum for P. brevicostata is particularly telling, I think.  (And I have specimens with length as short as 72 µm.)  In his description in Vol. 1 of the Diatoms of Europe, Krammer mentions that the taxonomy of P. brevicostata has been confused by many authors, and not all descriptions and images in the literature represent valid identifications.  Krammer bases his identification directly on measurements of Cleve's iconotype.

Pinnularia sp. H is a closer match for Pinnularia cruxarea Krammer, and I offered this ID in the earlier version of my floral list.  I now think this ID is wrong.  Although P. cruxarea is in the gibba-complex, and has close morphometrics, there is at least one significant difference: Krammer says that the fascia in cruxarea appears only on larger specimens, and is typically asymmetrical.  Pinnularia sp. H always has a fascia, even in smaller specimens, and the fascia is always symmetrical -- or virtually so.  Judging from Krammer's images, P. cruxarea has spots in the central area that are much less clear, and of a somewhat different nature, apparently often broken into a number of distinct flecks.  The specimens from Toome Bridge are all very consistent, with little variation.

Thanks a lot for asking the question!  I always feel that talking about taxonomy is about all I have to offer the group, since my slide-making ability is poor, my microtechnique is close to nonexistent, and I'm generally a klutz with any sort of equipment.  No manual dexterity, plus a worsening old-age tremor.  And I'm still trying to learn the basics of sample cleaning............!

Warmest regards,

Dick


From: klaus.kemp
To: diatom_forum@...
Sent: Tuesday, August 7, 2012 11:59 AM
Subject: [diatom_forum] Re: ID challenge_02

 
Dick,
It seems you should be congratulated for your excellent idea of creating a Toome Bridge image database. I have to say that it has caused me to be able to dig out some of the slide I have made with the only identification being to Genus, now I am a little wiser. This is an area that Bernard Hartley was keen for me to come to grips with and I miss his mentoring. Regarding your Pinnularia H I would have placed it in Pinnularia brevicostata Cleve, so now it is your turn to mentor me, what have I missed in my naming?
Klaus

--- In diatom_forum@..., Richard Carter wrote:
>
> I would agree, Klaus.  For those interested, there are some excellent SEM images of this taxon in the set that Bill Dailey has made available on his website.  There are hyperlinks in my file entitled "Dunkirk Diatoms".
>
> Dick
>
>
>
> ________________________________
> From: klaus.kemp <klaus.kemp@...>
> To: diatom_forum@...
> Sent: Sunday, August 5, 2012 5:57 AM
> Subject: [diatom_forum] Re: ID challenge_02
>
> Keith,
> I think this might be Aulacodiscus rogersii (Bailey) A. Schmidt, but will see what others think. Can you tell me where the location is?
> Klaus
>