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Photo#159817
springtail - Ptenothrix beta

springtail - Ptenothrix beta
Anthony Chabot Regional Park, Alameda County, California, USA
October 28, 2007
Size: 1-1.5mm
Hopefully this is the right family (short pointed 4th antennal segment).
At first I thought this was the same genus as the one I posted earlier this year, but I can't make out a "subsegmented apical part of the 3rd antennal segment" on this one.

Images of this individual: tag all
springtail - Ptenothrix beta springtail - Ptenothrix beta

Moved

Ptenothrix beta
Good point, Joyce!

Moved
Moved from Ptenothrix.

Ptenothrix cf. renateae
It is indeed the same species as you have posted before. It is a juvenile specimen. The pigmentation is not yet fully developed. But it compares well with that of the other specimens: such as the white 'neck' area, the white 'cross-like' pattern on the anterior part of the dorsum, the bilateral array of dark spots at the posterior part of the dorsum.
That we cannot see the sugsegmentation of the 3rd antennal segment is also due to fact that it is a juvenile specimen in which the subsegmentation is not yet fully developed.
I IDed the species provisionaly at 'cf. renateae' since the pigmentation matches best but not perfect with that of renateae.

 
thanks for the additional details
Thanks for educating me (and others) about springtails. Very interesting about the differences between juveniles and adults.

Should I go ahead and move these to a species page? I was going to leave the images at the genus level but I see you have them at the species level on your site.

 
Yes, go ahead
I check and recheck the IDs periodically. If it turns out otherwise, I'll let you know.

Moved
Moved from Dicyrtomidae.

Ptenothrix sp.
Yes, Joyce, the family is certainly correct.
I can't make out the "subsegmented apical part of the 3rd antennal segment" on this one either... But I assume it is present. IMHO this has to do with the aperture used. Also the large setae on the 2nd antennal segment are not visible.

 
thanks Frans
I'll have to get more samples of these guys. I took a lot more than two photos of this individual, and in none of them are the subsegments of the 3rd antennal segment clear, whereas they are clear in many of the photos I took of the other individual. There were some differences with my camera settings & amount of magnification, so it could be that.

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