Posts Tagged ‘Aphonopelma’

johnny-cash-tarantula-2 (1)


This systematic study documents the taxonomy, diversity, and distribution of the tarantula spider genusAphonopelma Pocock, 1901 within the United States. By employing phylogenomic, morphological, and geospatial data, we evaluated all 55 nominal species in the United States to examine the evolutionary history of Aphonopelma and the group’s taxonomy by implementing an integrative approach to species delimitation. Based on our analyses, we now recognize only 29 distinct species in the United States. We propose 33 new synonymies (A. apacheum, A. minchi, A. rothi, A. schmidti, A. stahnkei = A. chalcodes; A.arnoldi = A. armada; A. behlei, A. vogelae = A. marxi; A. breenei = A. anax; A. chambersi, A. clarum, A.cryptethum, A. sandersoni, A. sullivani = A. eutylenum; A. clarki, A. coloradanum, A. echinum, A. gurleyi, A.harlingenum, A. odelli, A. waconum, A. wichitanum = A. hentzi; A. heterops = A. moderatum; A. jungi, A.punzoi = A. vorhiesi; A. brunnius, A. chamberlini, A. iviei, A. lithodomum, A. smithi, A. zionis = A. iodius; A.phanum, A. reversum = A. steindachneri), 14 new species (A. atomicumsp. n., A. catalinasp. n., A.chiricahuasp. n., A. icenogleisp. n., A. johnnycashisp. n., A. maderasp. n., A. marekisp. n., A. moellendorfisp. n., A. parvumsp. n., A. peloncillosp. n., A. prenticeisp. n., A. saguarosp. n., A. superstitionensesp. n., and A. xwalxwalsp. n.), and seven nomina dubia (A. baergi, A. cratium, A. hollyi, A. mordax, A. radinum, A.rusticum, A. texense). Our proposed species tree based on Anchored Enrichment data delimits five major lineages: a monotypic group confined to California, a western group, an eastern group, a group primarily distributed in high-elevation areas, and a group that comprises several miniaturized species. Multiple species are distributed throughout two biodiversity hotspots in the United States (i.e., California Floristic Province and Madrean Pine-Oak Woodlands). Keys are provided for identification of both males and females. By conducting the most comprehensive sampling of a single theraphosid genus to date, this research significantly broadens the scope of prior molecular and morphological investigations, finally bringing a modern understanding of species delimitation in this dynamic and charismatic group of spiders.

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Phylogeographical studies in the Mojave and Sonoran deserts often find genetic discontinuities that pre-date the Pleistocene. A recent synthesis of phylogeographical data, called the Mojave Assembly Model, provides a hypothesis for the historical assembly of these desert biotas but does not adequately capture the complexity of pre-Pleistocene vicariance events. We tested this model and assessed pre-Pleistocene divergences by exploring the phylogeography of theAphonopelma mojave group, which is composed of turret-building tarantula species from the Mojave and Sonoran deserts.


Mojave and Sonoran deserts, south-western USA.


We augmented the sampling from a previous study by sequencing mitochondrial DNA (COI) from new material of the A. mojave group. We used phylogenetic and network analyses to identify clades and a molecular clock and lineages-through-time plots (LTT plots) to explore the timing and tempo of diversification. We tested for demographic expansion using neutrality tests and mismatch distributions. Species distribution models (SDMs) were constructed to compare current suitable habitat to that at the Last Glacial Maximum (LGM).


Phylogenetic, network and molecular-clock analyses identified six major clades that probably diverged during the late Miocene. The rate of diversification appears to have slowed during the Pliocene. Most clades exhibit signals of recent demographic expansion. SDMs predicted that suitable habitat shifted south and to lower elevations during the LGM.

Main conclusions

Phylogeographical analyses suggest that the A. mojave group experienced a burst of diversification in the late Miocene, followed by population expansions during the Pleistocene. Six major clades with origins in the late Miocene cannot be adequately explained by the Mojave Assembly Model. We propose the novel hypothesis that Miocene extensional tectonics caused populations to diverge in allopatry by producing low-elevation habitat barriers. Geological models, such as kinematic reconstructions, provide an ideal but underutilized framework for testing biogeographical hypotheses in these deserts and the wider Basin and Range Province.

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Random pictures from 2010 in Amarillo Texas:

T hawk 2 T hawk 1Peps


Blog title update:  Expanding  into news with general arachnids relevant to North America all in one place.  Mexico and the western states in the U.S. presents various transitions zones and micro habitats and is thus unique in arachnid taxa.

Hope you enjoy the site for educational and regional informations !


Chad Lee B.Sc. 1995.

Biology and Natural Resource Management.  Texas Certified Applicator



Tarantulas in the North American genus Aphonopelma are poorly known due to their challenging patterns of morphological variation and questionable taxonomy; few specimens can be confidently identified using existing keys or comparisons to original descriptions. In an effort to identify new strategies for resolving what has been characterized as a “taxonomic and nomenclatural nightmare”, we employed five different approaches for delimiting species in a group of closely related tarantulas from the Mojave Desert in the southwestern United States. These methods included the application of single techniques (morphology, DNA barcoding, shared genealogical exclusivity among independent loci, and generalized mixed Yule coalescent) and an integrative approach that incorporates genealogical and ecological information. Results demonstrate that the taxonomy of these spiders as presently defined underestimates actual species-level diversity and the group is in need of revision. The number of species delimited by each approach, however, was variable and we argue that it is this discordance that emphasizes the importance of incorporating multiple lines of evidence into an integrative taxonomic framework that can be used for constructing robust taxonomic hypotheses for Aphonopelma species




Citation: Hamilton CA, Formanowicz DR, Bond JE (2011) Species Delimitation and Phylogeography of Aphonopelma hentzi (Araneae, Mygalomorphae, Theraphosidae): Cryptic Diversity in North American Tarantulas.

The primary objective of this study is to reconstruct the phylogeny of the hentzispecies group and sister species in the North American tarantula genus,Aphonopelma, using a set of mitochondrial DNA markers that include the animal “barcoding gene”. An mtDNA genealogy is used to consider questions regarding species boundary delimitation and to evaluate timing of divergence to infer historical biogeographic events that played a role in shaping the present-day diversity and distribution. We aimed to identify potential refugial locations, directionality of range expansion, and test whether A. hentzi post-glacial expansion fit a predicted time frame.