 |
| Aphonopelma jacobii Hamilton & Hendrixson, in Hamilton, Hendrixson & Bringas, 2024 |
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.
Key words: Biodiversity hotspot, Chiricahua Mountains, conservation, cryptic species, molecular systematics, phylogenomics, spider taxonomy
 |
| Live habitus of Aphonopelma jacobii sp. nov. a male holotype (APH-5002) b female paratype (APH-5001). |
Aphonopelma jacobii Hamilton & Hendrixson, 2024, sp. nov.
Diagnosis: 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, but its distribution overlaps with A. chalcodes Chamberlin, 1940, A. chiricahua, A. gabeli Smith, 1995, and A. vorhiesi at lower elevations in the oak and pine-oak woodlands.
...
Etymology: The specific epithet is a patronym in honor of our friend, Michael A. Jacobi, who facilitated many of our field trips into the Chiricahua Mountains in 2018 and 2019. In addition, he generously carried out field work in the MSI on our behalf and discovered many important specimens, including the first female burrows of A. chiricahua and this remarkable new species. His tireless work in the field and passion for natural history have immensely helped improve our knowledge of tarantula biology and biodiversity in the Chiricahua Mountains and surrounding areas.
 |
| Habitat images of Aphonopelma jacobii sp. nov. from the Chiricahua Mountains, Cochise County, Arizona a, b type locality along Forest Road 42D above Onion Saddle c, d Barfoot Park e along Forest Road 42A f open burrow at the type locality. Photographs of images d and e provided by Michael A. Jacobi. |
Chris A. Hamilton, Brent E. Hendrixson and Karina Silvestre Bringas. 2024. Discovery of A New Tarantula Species from the Madrean Sky Islands and the first documented instance of syntopy between two montane endemics (Araneae, Theraphosidae, Aphonopelma): A Case of prior mistaken identity. ZooKeys. 1210: 61-98. DOI: doi.org/10.3897/zookeys.1210.125318
