Posts Tagged ‘Biogeography’



Scorpions are among the oldest terrestrial arthropods, which are distributed worldwide, except for Antarctica and some Pacific islands. Scorpion envenomation represents a public health problem in several parts of the world. Mexico harbors the highest diversity of scorpions in the world, including some of the world’s medically important scorpion species. The systematics and diversity of Mexican scorpion fauna has not been revised in the past decade; and due to recent and exhaustive collection efforts as part of different ongoing major revisionary systematic projects, our understanding of this diversity has changed compared with previous assessments. Given the presence of several medically important scorpion species, the study of their venom in the country is also important. In the present contribution, the diversity of scorpion species in Mexico is revised and updated based on several new systematic contributions; 281 different species are recorded. Commentaries on recent venomic, ecological and behavioral studies of Mexican scorpions are also provided. A list containing the most important peptides identified from 16 different species is included. A graphical representation of the different types of components found in these venoms is also revised. A map with hotspots showing the current knowledge on scorpion distribution and areas explored in Mexico is also provided.

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Two new species of Pseudouroctonus are described from southeastern Arizona, USA, Pseudouroctonus santarita, sp. nov. from the Santa Rita Mountains and P. kremani, sp. nov. from the Santa Catalina Mountains. These new species are closely related to P. apacheanus (Gertsch et Soleglad, 1972). A combination of morphological differences in the hemispermatophore, the mating plug, and several morphometric-based characters are identified as diagnostic. New substructures are identified for the mating plug.

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Camel spiders (Solifugae) are a diverse but poorly studied order of arachnids. No robust phylogenetic analysis has ever been carried out for the order or for any family within the Solifugae. We present a molecular phylogenetic analysis of the endemic North American family Eremobatidae Kraepelin, 1899, the first such analysis of a family of Solifugae. We use a multi-locus exemplar approach using DNA sequences from partial nuclear (28S rDNA and Histone H3) and mitochondrial (16S rRNA and Cytochrome c Oxidase I) gene loci for 81 ingroup exemplars representing all genera of Eremobatidae and most species groups within the genera Eremobates Banks, 1900, Eremochelis Roewer, 1934, andHemerotrecha Banks, 1903. Maximum Likelihood and two Bayesian analyses consistently recovered the monophyly of Eremobatidae, Eremorhax Roewer, 1934 andEremothera Muma, 1951 along with a group comprising all subfamily Eremobatinae Kraepelin, 1901 exemplars except Horribates bantai Muma, 1989 and a group comprising all Eremocosta Roewer, 1934 exemplars except Eremocosta acuitalpanensis (Vasquez and Gavin, 2000). The subfamily Therobatinae Muma, 1951 and the genera Chanbria Muma, 1951, Hemerotrecha, Eremochelis, and Eremobateswere polyphyletic or paraphyletic. Only the banksi group of Hemerotrecha was monophyletic; the other species groups recognized within Eremobates, Eremochelis, and Hemerotrecha were paraphyletic or polyphyletic. We found no support for the monophyly of the subfamily Therobatinae. A time-calibrated phylogeny dated the most recent common ancestor of extant eremobatids to the late Eocene to early Miocene, with a mean estimate in the late Oligocene (32.2 Ma)




A new species of Vaejovis is described from the Mexican state of Aguascalientes. It is assigned to the “mexicanus” group and compared with similar species from Jalisco, Guanajuato, and San Luis Potosí. A map with their known distributions is provided.







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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The scorpion genus Diplocentrus Peters, 1861, endemic to North and Central America, is the most diverse in family Diplocentridae
Karsch, 1880. There is considerable morphological variation among the species of Diplocentrus. It is necessary to test the monophyly and
phylogenetic position of Diplocentrus in order to revise its diagnosis and taxonomic limits. The present contribution provides a phylogenetic
analysis of 29 species of Diplocentrus, five exemplar species representing the three putatively most closely related diplocentrid genera,
and an exemplar of a more distantly related diplocentrid genus. The analysis was based on 95 morphological characters and 4202 aligned
nucleotides from DNA sequences of five markers in the nuclear and mitochondrial genomes. Separate and simultaneous parsimony analyses
of the morphological and DNA sequence data were conducted with equal weighting and six implied weighting regimes. The nuclear
and mitochondrial DNA datasets were also analyzed separately and simultaneously with Bayesian inference. The resulting topologies
recovered the monophyly of Diplocentrus, with the exception of two neobothriotaxic species from central Mexico, for which a new genus
Kolotl Santibáñez-López et al., 2014, is justified. The keyserlingii group, as previously defined, was not monophyletic due to the placement
of two species in the mexicanus group; the rest of its component species were monophyletic, however. A third clade was recovered that has
not been previously recognized: the zacatecanus group, comprising four species from northern Mexico and the southwestern U.S.A. New
insights are provided concerning relationships among Diplocentrus and the diplocentrid genera Bioculus Stahnke, 1968 and Didymocentrus
Kraepelin, 1905, the phylogenetic positions of which were previously ambiguous..

Edit note with format issues…Thanks and will try to correct.



The first rigorous analysis of the phylogeny of the North American vaejovid scorpion subfamily Syntropinae is presented. The analysis is based on 250 morphological characters and 4221 aligned DNA nucleotides from three mitochondrial and two nuclear gene markers, for 145 terminal taxa, representing 47 species in 11 ingroup genera, and 15 species in eight outgroup genera. The monophyly and composition of Syntropinae and its component genera, as proposed by Soleglad and Fet, are tested. The following taxa are demonstrated to be para- or polyphyletic: Smeringurinae; Syntropinae; Vaejovinae; Stahnkeini; Syntropini; Syntropina; Thorelliina; Hoffmannius; Kochius; and Thorellius. The spinose (hooked or toothed) margin of the distal barb of the sclerotized hemi-mating plug is demonstrated to be a unique, unambiguous synapomorphy for Syntropinae, uniting taxa previously assigned to different subfamilies. Results of the analysis demonstrate a novel phylogenetic relationship for the subfamily, comprising six major clades and 11 genera, justify the establishment of six new genera, and they offer new insights about the systematics and historical biogeography of the subfamily, and the information content of morphological character systems.

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Thanks to the Scorpion Files posting the news.  Its been a long time coming to see the results from the Scorpion Lab at AMNH.

A new scorpion species, Vaejovis grayae sp. nov. is described and placed in the “vorhiesi” group of the genus Vaejovis. This small brown species is found near Yarnell, Arizona, USA. It appears most similar to V. trinityae Ayrey and V. crumpi Ayrey et Soleglad. It can be distinguished from the other members of the “vorhiesi” group by aunique combination of non-overlapping morphological characters and multilocus DNA data (Bryson et al., 2013). The pedipalp fixed finger has 6 ID denticles and the movable finger has 7, like most other northern Arizona “vorhiesi” group species. Another characteristic of this species is its unique Arizona chaparral habitat.


Published at Euscorpius Online Journal:  Occasional papers in scorpiology


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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



Vaejovis coalcoman sp. n. from Sierra de Coalcomán, in the northwestern part of the state of Michoacán, Mexico, is described. It belongs to the “mexicanus” group and it is compared with related species from the states of Jalisco and Guanajuato. A map with the known distribution of the related taxa is provided.

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