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Fig. 5 in A new species of whiptail armored catfish, genus Pseudohemiodon (Siluriformes: Loricariidae) from the Orinoco River basin, Llanos region of Colombia and Venezuela

Fig. 5. Map of northern South America (Colombia and Venezuela) showing capture localities of Pseudohemiodon unillano, red star is type locality, some symbols may represents more than one lot.

Fig. 3 in A new species of whiptail armored catfish, genus Pseudohemiodon (Siluriformes: Loricariidae) from the Orinoco River basin, Llanos region of Colombia and Venezuela

Fig. 3. Pseudohemiodon unillano, paratype, IAvH-P 19088, 183.2 mm SL. Detail of buccal ornamentation and teeth. Photograph by L. M. Mesa.

Fig. 1 in A new species of whiptail armored catfish, genus Pseudohemiodon (Siluriformes: Loricariidae) from the Orinoco River basin, Llanos region of Colombia and Venezuela

Fig. 1. Pseudohemiodon unillano, new species, holotype, IAvH-P 19034, 162.0 mm SL. Photograph by J. Lopez-Castaño.

Fig. 2 in A new species of whiptail armored catfish, genus Pseudohemiodon (Siluriformes: Loricariidae) from the Orinoco River basin, Llanos region of Colombia and Venezuela

Fig. 2. Pseudohemiodon unillano, paratype, IAvH-P 19088, 183.2 mm SL. Detail of mouth in live specimen. Photograph by A. Ortega-Lara.

opencc-zeroDec 2004View details →

FIGURE 5 in A new species of whiptail stingray of the genus Dasyatis Rafinesque, 1810 from the Southwestern Atlantic Ocean (Chondrichthyes: Myliobatiformes: Dasyatidae)

FIGURE 5: Dasyatis colarensis n. sp., UERJ 2006, paratype. Detail of mouth showing the coloration of the lower lip margin.

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Data from: Understanding species boundaries that arise from complex histories: Gene flow across the speciation continuum in the spotted whiptail lizards

Gene flow between diverging lineages challenges the resolution of species boundaries and the understanding of evolutionary history in recent radiations. Here, we integrate phylogenetic and coalescent tools to resolve reticulate patterns of diversification and use a perspective focused on evolutionary mechanisms to distinguish interspecific and intraspecific taxonomic variation. We use this approach to resolve the systematics for one of the most intensively studied but difficult to understand groups of reptiles: the spotted whiptail lizards of the genus Aspidoscelis (A. gularis complex). Whiptails contain the largest number of unisexual species known within any vertebrate group and the spotted whiptail complex has played a key role in the generation of this diversity through hybrid speciation. Understanding lineage boundaries and the evolutionary history of divergence and reticulation within this group is therefore key to understanding the generation of unisexual diversity in whiptails. Despite this importance, long-standing confusion about their systematics has impeded understanding of which gonochoristic species have contributed to the formation of unisexual lineages. Using reduced representation genomic data, we resolve patterns of divergence and gene flow within the spotted whiptails and clarify patterns of hybrid speciation. We find evidence that biogeographically structured ecological and environmental variation has been important in morphological and genetic diversification, as well as the maintenance of species boundaries in this system. Our study elucidates how gene flow among lineages and the continuous nature of speciation can bias the practice of species delimitation and lead taxonomists operating under different frameworks to different conclusions (here we propose that a two species arrangement best reflects our current understanding). In doing so, this study provides conceptual and methodological insights into approaches to resolving diversification patterns and species boundaries in rapid radiations with complex histories, as well as long-standing taxonomic challenges in the field of systematic biology.

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opencc-by-4.0Mar 2007View details →

Fig. 3 in Hybridization Between the Endangered Unisexual Gray-Checkered Whiptail Lizard (Aspidoscelis dixoni) and the Bisexual Western Whiptail Lizard (Aspidoscelis tigris) in Southwestern New Mexico

Fig. 3. Dorsolateral views of three whiptail lizards (Aspidoscelis). Upper, diploid unisexual A. dixoni C from Antelope Pass (AMNH R-148360, body length 96 mm). Middle, triploid female hybrid of A. dixoni C X A. tigris punctilinealis from Antelope Pass (AMNH R-148141, body length 93 mm). Lower, diploid bisexual A. t. punctilinealis male from Antelope Pass (AMNH R-148113, body length 90 mm).

Fig. 51 in Hybridization Among Western Whiptail Lizards (Cnemidophorus Tigris) In Southwestern New Mexico: Population Genetics, Morphology, And Ecology In Three Contact Zones

Fig. 51. Electrophoretic phenotypes of proteins of several subspecies of C. tigris. Left. ESTD polymorphism in C. t. septentrionalis. The fluorescent patterns were photographed in ultraviolet light. Right. Banding patterns of PGM2 that distinguish septentrionalis (SEP, genotype cc) from punctilinealis (PUN genotype dd), marmoratus (MAR, genotype dd), and aethiops (genotype dd, not illustrated). Arrows indicate sites of sample application; anode is to the right.

Fig. 49 in Hybridization Among Western Whiptail Lizards (Cnemidophorus Tigris) In Southwestern New Mexico: Population Genetics, Morphology, And Ecology In Three Contact Zones

Fig. 49. The contact region. Horizontal lines represent range of pure punctilinealis (coloration indices of 0–0.1; table 24), and vertical lines pure marmoratus (coloration indices of 0.8–1.0). Sites in between (2–5, 18, 19, 26, and 41–44) represent primarily hybrids (coloration indices of 0.11–0.79).

Fig. 52 in Hybridization Among Western Whiptail Lizards (Cnemidophorus Tigris) In Southwestern New Mexico: Population Genetics, Morphology, And Ecology In Three Contact Zones

Fig. 52. Differences in the tissue distribution of lactate dehydrogenase, a tetramer. Top (six lanes) LDH1 predominates in heart. Bottom (five lanes). Both LDH1 and LDH2 are active in liver and the banding patterns include numerous isozymes composed of subunits of both. Note the fivebanded patterns for LDH1 for heterozygous diploid C. neomexicanus (NEO) and a triploid hybrid (HYB) of neomexicanus × tigris. In the heart tissue, LDH1 genotype ab for neomexicanus, the isozymes approximate activities of 1:4:6:4:1. For the triploid hybrid with genotype aab, the faster migrating isozymes stain most intensely (activities approximate the theoretically expected ratio of 16:32:24:8:1). These patterns are consistent with the origin of the hybrid from a mating between C. neomexicanus (NEO) and C. t. punctilinealis (PUN). Other abbreviations are: UNI, C. uniparens; MAR, C. t. marmoratus. Arrow indicates sites of sample application; anode is to the right.

Fig. 47 in Hybridization Among Western Whiptail Lizards (Cnemidophorus Tigris) In Southwestern New Mexico: Population Genetics, Morphology, And Ecology In Three Contact Zones

Fig. 47. Relationship between body length and number of eggs per clutch in specimens of C. tigris from the contact region. MAR, pure marmoratus; PUN, pure punctilinealis; HYB, hybrids. Data are summarized in table 30 and figure 48.

Fig. 48 in Hybridization Among Western Whiptail Lizards (Cnemidophorus Tigris) In Southwestern New Mexico: Population Genetics, Morphology, And Ecology In Three Contact Zones

Fig. 48. Relationship between body length and number of eggs per clutch (same data as table 30 and fig. 47), showing 95% confidence intervals (broken lines) for each plot. M, pure marmoratus P, pure punctilinealis; H, hybrids.

Fig. 46 in Hybridization Among Western Whiptail Lizards (Cnemidophorus Tigris) In Southwestern New Mexico: Population Genetics, Morphology, And Ecology In Three Contact Zones

Fig. 46. Polygons and letters representing the scores of 27 specimens of C. tigris on the first two principal components extracted from the correlation matrix of nine morphological characters observed in the southern transect (table 28). P represents 9 punctilinealis from site 36; M, 9 marmoratus from site 48; and H, 9 hybrids from site 42, the center of the southern hybrid zone (fig. 5).

Fig. 44 in Hybridization Among Western Whiptail Lizards (Cnemidophorus Tigris) In Southwestern New Mexico: Population Genetics, Morphology, And Ecology In Three Contact Zones

Fig. 44. Polygons and letters representing the scores of 39 specimens of C. tigris on the first two principal components extracted from the correlation matrix of nine morphological characters observed in the northern transect (table 28). P represents 10 punctilinealis from site 1; M, nine marmoratus from site 7; and H, 20 hybrids from site 3, the center of the northern hybrid zone (fig. 4).

Fig. 45 in Hybridization Among Western Whiptail Lizards (Cnemidophorus Tigris) In Southwestern New Mexico: Population Genetics, Morphology, And Ecology In Three Contact Zones

Fig. 45. Polygons and letters representing the scores of 85 specimens of C. tigris on the first two principal components extracted from the correlation matrix of nine morphological characters observed in the central transect (table 28). P represents 29 punctilinealis from site 20; M, 26 marmoratus from site 29; and H, 30 hybrids from site 26, the center of the central hybrid zone (fig. 5).

Fig. 43 in Hybridization Among Western Whiptail Lizards (Cnemidophorus Tigris) In Southwestern New Mexico: Population Genetics, Morphology, And Ecology In Three Contact Zones

Fig. 43. Scores of sample means for the first principal component extracted from the variance– covariance matrix of arcsine squareroottransformed frequencies of marmoratus alleles at the seven highly polymorphic loci (IDDH, sMDHP, EST2, PEPB, PEPD, GPI, and TF) plotted against sample locality on all three transects of the hybrid zones, as in figure 42. Data are from tables 6, 8, and 10.

Fig. 50 in Hybridization Among Western Whiptail Lizards (Cnemidophorus Tigris) In Southwestern New Mexico: Population Genetics, Morphology, And Ecology In Three Contact Zones

Fig. 50. Grassland WNW of Lordsburg, looking to the NW toward the Summit Hills that are immediately north of site 12 (fig. 49). Dark band of vegetation at the base of the hills is the creosote community. Thin diagonal line across grassland is the railroad, with shrubs along the tracks. Aerial photograph taken on 1 September 1990.

Fig. 41 in Hybridization Among Western Whiptail Lizards (Cnemidophorus Tigris) In Southwestern New Mexico: Population Genetics, Morphology, And Ecology In Three Contact Zones

Fig. 41. Mean frequency of the marmoratus nuclear alleles averaged over all four diagnostic loci of proteins, of the marmoratus 12S ribosomal mtDNA haplotypes, and of the marmoratus coloration hybrid indices at sites along the southern transect (fig. 5). Site 42 represents the center of the southern hybrid zone. Compare with figure 32.

Fig. 42 in Hybridization Among Western Whiptail Lizards (Cnemidophorus Tigris) In Southwestern New Mexico: Population Genetics, Morphology, And Ecology In Three Contact Zones

Fig. 42. Scores of sample means for the first principal component extracted from the variance– covariance matrix of arcsine squareroottransformed frequencies of marmoratus coloration characters plotted against sample locality on all three transects of the hybrid zones: northern (sites 1–7), central (sites 20–30 + 29), and southern (sites 36–40, 42, 44, 46, and 48). Numbers plotted are the collecting site numbers. Data are summarized in table 24.

Fig. 40 in Hybridization Among Western Whiptail Lizards (Cnemidophorus Tigris) In Southwestern New Mexico: Population Genetics, Morphology, And Ecology In Three Contact Zones

Fig. 40. Mean frequency of the marmoratus nuclear alleles averaged over all four diagnostic loci of proteins, of the marmoratus 12S ribosomal mtDNA haplotypes, and of the marmoratus coloration hybrid indices at sites along the central transect (fig. 5). Site 26 represents the center of the central hybrid zone. Compare with figure 31.