Aphonopelma jacobii

advan

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New species of Aphonoplema described!

Aphonopelma jacobii Chris A. Hamilton, Brent E. Hendrixson, Karina Silvestre Bringas 2024

https://zookeys.pensoft.net/article/125318

Abstract:
The Chiricahua Mountains in southeastern Arizona are renowned for their exceptional biodiversity and high levels of endemism. Morphological, genomic, behavioral, and distributional data were used to report the discovery of a remarkable new tarantula species from this range. Aphonopelma jacobii sp. nov. inhabits high-elevation mixed conifer forests in these mountains, but also co-occurs and shares its breeding period with A. chiricahua—a related member of the Marxi species group—in mid-elevation Madrean evergreen oak and pine-oak woodlands. This marks the first documented case of syntopy between two montane endemics in the Madrean Archipelago and adds to our knowledge of this threatened region’s unmatched tarantula diversity in the United States. An emended diagnosis and redescription for A. chiricahua are also provided based on several newly acquired and accurately identified specimens. Phylogenetic analyses of mitochondrial and genomic-scale data reveal that A. jacobii sp. nov. is more closely related to A. marxi, a species primarily distributed on the Colorado Plateau, than to A. chiricahua or the other Madrean Sky Island taxa. These data provide the evolutionary framework for better understanding the region’s complex biogeographic history (e.g., biotic assembly of the Chiricahua Mountains) and conservation of these spiders.


October of 2019, Tom Patterson @Philth and I flew down to AZ to meet up with Michael Jacobi, Brent Hendrixson and Chris Hamilton to collect more material for this description.

Here's some photos from the trip:

Adult male


Adult female #1




Adult female #2






 
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advan

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I am starting to think these are hybrids in the wild with so many Aphonopelmas🤔
Tell that to the authors who did extensive genetic testing. I would encourage you to click the link and read the description to further you understanding of how they came to the conclusion that these are a new species. ;)
 

l4nsky

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advan

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Just for my understanding, this specimen is also A. jacobii and not some other 'new' Aphonopelma (A. sp nov)?

https://youtube.com/shorts/uUyf3VwbU4A?feature=shared

I have a female, but she looks much closer to the specimen in your short than to the specimen that @advan has shared. I realize it's likely a lighting issue, but the only way to know is to ask :) .
The female in the video is a freshly molted female. The two in my pics are further along in their molt cycle. Female #1 being further along her molt cycle than female #2.
 

l4nsky

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The female in the video is a freshly molted female. The two in my pics are further along in their molt cycle. Female #1 being further along her molt cycle than female #2.
Ahh, thanks for confirming they're one in the same. The MF in the collection will darken considerably between molts like female #2, but she's never appeared like female #1 to me. It's likely an age issue as well, with her being on the younger side.

Freshly molted though, she's a fairly bright and reflective slate gray that will almost appear blue under some lighting conditions.
 

ggauna

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Pretty sure I found one of these as a kid near Flagstaff and thought it was a T. vegans 😂
I grew up in nor az In a town called Williams and I swear I would catch these when I was little what’s the difference between the Marxi and Jacobii they look very similar
 

l4nsky

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I grew up in nor az In a town called Williams and I swear I would catch these when I was little what’s the difference between the Marxi and Jacobii they look very similar
Outside of jacobii being severely geographically limited, there is also size. Marxi will be 5"+ DLS whereas jacobii is a dwarf species that maxes closer to 3".
 

advan

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I grew up in nor az In a town called Williams and I swear I would catch these when I was little what’s the difference between the Marxi and Jacobii they look very similar
The description linked has all the info you need.

" Aphonopelma jacobii sp. nov. is a member of the Marxi species group and can be distinguished by a combination of morphological, genomic, behavioral, and distributional features. This species is a mid- to late-fall breeder endemic to the Chiricahua Mountains in southeastern Arizona. Nuclear DNA identifies A. jacobii sp. nov. as a monophyletic lineage (Fig. 2) that is sister to A. marxi (distributed along the Colorado Plateau) and phylogenetically distinct from the other tarantula species endemic to the Chiricahua Mountains (i.e., A. chiricahua). Aphonopelma jacobii sp. nov. is probably the only tarantula species encountered in the high-elevation mixed conifer forests of the Chiricahua Mountains,"
 

l4nsky

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Aphonopelma jacobii sp. nov. is probably the only tarantula species encountered in the high-elevation mixed conifer forests of the Chiricahua Mountains
Famous last words lol.
 
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