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opencc-zeroDec 2012View details →

Data from: Multilocus species delimitation in a complex of morphologically conserved trapdoor spiders (Mygalomorphae, Antrodiaetidae, Aliatypus)

Species are a fundamental unit for biological studies, yet no uniform guidelines exist for determining species limits in an objective manner. Given the large number of species concepts available, defining species can be both highly subjective and biased. Although morphology has been commonly used to determine species boundaries, the availability and prevalence of genetic data has allowed researchers to use such data to make inferences regarding species limits. Genetic data also have been used in the detection of cryptic species, where other lines of evidence (morphology in particular) may underestimate species diversity. In this study, we investigate species limits in a complex of morphologically conserved trapdoor spiders (Mygalomorphae, Antrodiaetidae, Aliatypus) from California. Multiple approaches were used to determine species boundaries in this highly genetically fragmented group, including both multilocus discovery and validation approaches (plus a chimeric approach). Additionally, we introduce a novel tree-based discovery approach using species trees. Results suggest that this complex includes multiple cryptic species, with two groupings consistently recovered across analyses. Due to incongruence across analyses for the remaining samples, we take a conservative approach and recognize a three species complex, and formally describe two new species (Aliatypus roxxiae, sp. nov. and Aliatypus starretti, sp. nov.). This study helps to clarify species limits in a genetically fragmented group and provides a framework for identifying and defining the cryptic lineage diversity that prevails in many organismal groups.

opencc-zeroDec 2011View details →

Data from: Crossing the uncrossable: novel trans-valley biogeographic patterns revealed in the genetic history of low dispersal mygalomorph spiders (Antrodiaetidae, Antrodiaetus) from California

Antrodiaetus riversi is a dispersal-limited, habitat specialized mygalomorph spider species endemic to mesic woodlands of northern and central California. Here we build upon prior phylogeographic research using a much larger geographic sample and include additional nuclear genes, providing more detailed biogeographic insights throughout the range of this complex. Of particular interest is the uncovering of unexpected and replicated trans-valley biogeographic patterns, where in two separate genetic clades western haplotypes in the California south Coast Ranges are phylogenetically closely-related to eastern haplotypes from central and northern Sierran foothills. In both instances, these trans-valley phylogenetic patterns are strongly supported by multiple genes. These western and eastern populations are currently separated by the Central Valley, a well-recognized modern-day and historical biogeographic barrier in California. For one clade the directionality is clearly northeast to southwest, and all available evidence is consistent with a jump dispersal event estimated at 1.2-1.3 million years ago. During this time period, paleogeographic data indicate that northern Sierran rivers emptied to the ocean in the south Coast Ranges, rather than at the San Francisco Bay. For the other trans-valley clade genetic evidence is less conclusive regarding the mechanism and directionality of biogeographic exchange, although the estimated timeframe is similar (approximately 1.8 Ma). Despite the large number of biogeographic studies previously conducted in central California, to the best of our knowledge no prior studies have discussed or revealed a northern Sierran to south Coast Range biogeographic connection. This uniqueness may reflect the low-dispersal biology of mygalomorph spiders, where "post-event" gene exchange rarely erases historical biogeographic signal.

FIGURE 3 in A new trapdoor spider species from the southern Coast Ranges of California (Mygalomorphae, Antrodiaetidae, Aliatypus coylei, sp. nov,), including consideration of mitochondrial phylogeographic structuring

FIGURE 3. Female spermathecae, viewed ventrally: A) MY1013 (CASENT9039431) paratype female, Carmel Valley Road (site 18), B) MY1326, Laureles Grade Road (site 13), C) MY374, Jack's Peak County Park (site 12), D) MY955, W of Pinnacles NM (site 8), E) MY3059, Palo Colorado Road (site 15), F) MY4194, Harlan Mtn Road (site 5), G) MY4362, Hidden Valley Road (site 1), H) MY1645, Coalinga Road (site 10), I) MY1642, Lonoak Road (site 11), J) MY829, E of Santa Margarita (site 22), K) MY1010, S of Gorda (site 20), L) MY2671, Kanan Dume Road (site 24). Colored dots correspond to genetic groups of Fig. 5. Site numbers correspond to Table 1 and Fig. 1C. Scale bar = 0.5 mm.

FIGURE 2 in A new trapdoor spider species from the southern Coast Ranges of California (Mygalomorphae, Antrodiaetidae, Aliatypus coylei, sp. nov,), including consideration of mitochondrial phylogeographic structuring

FIGURE 2. Male holotype, MY999 (CASENT9039430), W of Arroyo Center (site 19): A) carapace and abdomen, viewed dorsally, B) left pedipalp, viewed retrolaterally, C) left leg I, viewed retrolaterally, D) sternum and chelicerae, viewed ventrally, E) palpal bulb, viewed ventrally. Scale bar A–D = 1 mm, E = 0.5 mm.

FIGURE 1. A in A new trapdoor spider species from the southern Coast Ranges of California (Mygalomorphae, Antrodiaetidae, Aliatypus coylei, sp. nov,), including consideration of mitochondrial phylogeographic structuring

FIGURE 1. A) Adult female Aliatypus coylei (MY4194), Harlan Mountain Road, Gabilan Range, San Benito County; B) Aliatypus trapdoor, Harlan Mountain Road, Gabilan Range, San Benito County; C) Known distribution of Aliatypus coylei. Site numbers correspond to Table 1; some geographically adjacent sites are represented by a single white circle. Regional records of other Aliatypus species as follows: red dots = A. janus, blue dots = A. torridus (records from Coyle 1974, Coye & Icenogle 1994; Satler et al. in review; personal observations). San Luc = Santa Lucia Range, Gab = Gabilan Range, Diablo = Diablo Range.

FIGURE 5. A in A new trapdoor spider species from the southern Coast Ranges of California (Mygalomorphae, Antrodiaetidae, Aliatypus coylei, sp. nov,), including consideration of mitochondrial phylogeographic structuring

FIGURE 5. A) Majority-rule consensus phylogram resulting from partitioned Bayesian analysis. Aliatypus coylei haplotypes are labeled with specimen number, location abbreviation, and site number (corresponding to Fig. 1). Posterior probability values are shown for both partitioned (above branches) and unpartitioned (below branches) analyses. Samples with morphological images included in Figs 3 and 4 are highlighted. B) Geographic distribution of haplotype groupings. Site numbers correspond to Fig. 1.

FIGURE 4 in A new trapdoor spider species from the southern Coast Ranges of California (Mygalomorphae, Antrodiaetidae, Aliatypus coylei, sp. nov,), including consideration of mitochondrial phylogeographic structuring

FIGURE 4. Female sternal sigilla, viewed ventrally: A) paratype female, MY1013, Carmel Valley Road (site 18), B) MY374, Jack's Peak County Park (site 12), C) MY2671, Kanan Dume Road (site 24), D) MY4194, Harlan Mtn Road (site 5), E) MY1642, Lonoak Road (site 11) F) MY829, E of Santa Margarita (site 22). Colored dots correspond to genetic groups of Fig. 5. Site numbers correspond to Table 1 and Fig. 1C. Scale bar = 1 mm.

publicOct 2012View details →

Data from: Crossing the uncrossable: novel trans-valley biogeographic patterns revealed in the genetic history of low dispersal mygalomorph spiders (Antrodiaetidae, Antrodiaetus) from California

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