Using a novel combination of palaeohabitat modelling and genetic mixture analyses, we identify an... more Using a novel combination of palaeohabitat modelling and genetic mixture analyses, we identify and assess a sea-level-driven recolonization process following the Last Glacial Maximum (LGM). Our palaeohabitat modelling reveals dramatic changes in estuarine habitat distribution along the coast of California (USA) and Baja California (Mexico). At the LGM (approx. 20 kya), when sea level was approximately 130 m lower, the palaeo-shoreline was too steep for tidal estuarine habitat formation, eliminating this habitat type from regions where it is currently most abundant, and limiting such estuaries to a northern and a southern refugium separated by 1000 km. We assess the recolonization of estuaries formed during post-LGM sea-level rise through examination of refugium-associated alleles and approximate Bayesian computation in three species of estuarine fishes. Results reveal sourcing of modern populations from both refugia, which admix in the newly formed habitat between the refuges. We in...
Revista Mexicana de Biodiversidad www.ib.unam.mx/revista/ Revista Mexicana de Biodiversidad 87 (2... more Revista Mexicana de Biodiversidad www.ib.unam.mx/revista/ Revista Mexicana de Biodiversidad 87 (2016) 390-398 Taxonomy and systematics Morphometric and meristic characterization of the endemic Desert chub Gila eremica (Teleostei: Cyprinidae), and its related congeners in Sonora, Mexico
Records of gray whales (Eschrichtius robustus) at and near their two known calving sites in the G... more Records of gray whales (Eschrichtius robustus) at and near their two known calving sites in the Gulf of California (Sea of Cortés), México, are reviewed up to 1995. The sites of Tojahui/Yavaros (Sonora) and Bahía Santa María (Sinaloa) represented the most distant calving grounds regularly visited by the species. Prior observations (mainly in the 1950s and 1960s) revealed relatively small but seasonally consistent numbers of whales, with maximum counts, including calves, of 30 individuals at Bahía Santa María in 1954, and 17-19 at Tojahui/Yavaros in 1955, 1963 and 1971. Observations (initiated in 1979) as well as interviews with longtime local residents and fishermen, document a decline in numbers and occupancy times of whales, especially cow/calf pairs, visiting these sites. In contrast, 19th century whaling records indicate that many more gray whales were found seasonally along these coasts. The recent decline, leading to the apparent disappearance, is likely to be due to human-ind...
Plate tectonics and sediment processes control regional continental shelf topography. We examine ... more Plate tectonics and sediment processes control regional continental shelf topography. We examine the genetic consequences of how glacial-associated sea-level change interacted with variable near-shore topography since the last glaciation. We reconstructed the size and distribution of areas suitable for tidal estuary formation from the Last Glacial Maximum, ~20 thousand years ago, to present from San Francisco, California, USA (~38 °N) to Reforma, Sinaloa, Mexico (~25 °N). We assessed range-wide genetic structure and diversity of three co-distributed tidal estuarine fishes (California Killifish, Shadow Goby, Longjaw Mudsucker) along ~4,600 km using mitochondrial control region and cytB sequence, and 16–20 microsatellite loci from a total of 524 individuals. Results show that glacial-associated sea-level change limited estuarine habitat to few, widely separated refugia at glacial lowstand, and present-day genetic clades were sourced from specific refugia. Habitat increased during postglacial sea-level rise and refugial populations admixed in newly formed habitats. Continental shelves with active tectonics and/or low sediment supply were steep and hosted fewer, smaller refugia with more genetically differentiated populations than on broader shelves. Approximate Bayesian computation favored the refuge-recolonization scenarios from habitat models over isolation by distance and seaway alternatives, indicating isolation at lowstand is a major diversification mechanism among estuarine (and perhaps other) coastal species. Because sea-level change is a global phenomenon, we suggest this top-down physical control of extirpation-isolation-recolonization may be an important driver of genetic diversification in coastal taxa inhabiting other topographically complex coasts globally during the Mid- to Late Pleistocene and deeper timescales
Mitochondrial evidence for a new evolutionary significant unit within the Gila eremica lineage (T... more Mitochondrial evidence for a new evolutionary significant unit within the Gila eremica lineage (Teleostei, Cyprinidae) in Sonora, Northwest Mexico. We present the phylogenetic affinities and DNA barcode of Gila cf. eremica, a geographically isolated and morphologically divergent population from G. eremica DeMarais, 1991. Mitochondrial phylogenetic analyses of cyt-b, cox1 and nd2 show a clades pattern within the G. eremica lineage, placing G. cf. eremica in a clade of specific identity to and sharing a putative common ancestor with G. eremica from the Mátape River basin. The barcoding analysis using a character-based approach of CAOS showed seven single pure characters discriminating G. eremica from its regional congener G. purpurea, and one fixed character in G. cf. eremica discriminating it from G. eremica. These results and the recent detection of diagnostic morphological differences between G. cf. eremica and G. eremica support the hypothesis of Gila cf. eremica as an significant evolutionary unit within the G. eremica lineage.
A review of published research indicates that the Northern Gulf of California is, historically an... more A review of published research indicates that the Northern Gulf of California is, historically and currently, one of the most biologically productive marine regions on Earth. This high productivity is driven by a unique mix of factors, including: coastal upwelling, wind-driven mixing, extreme tidal mixing and turbulence, thermohaline circulation that moves intermediate waters into the mixed layer, coastal-trapped waves, regular sediment resuspension, and, to a lesser extent, agricultural runoff, released nutrients from erosion of ancient Colorado River Delta
Conservación de truchas natives mexicanas y su descubrimiento, estatus, protección y redescubrimi... more Conservación de truchas natives mexicanas y su descubrimiento, estatus, protección y redescubrimiento de la trucha del Conchos, la primera especie nativa. i 1 DEAN A
Errors in Nelson et al. (2004) that have come to our attention are listed below. Some of these we... more Errors in Nelson et al. (2004) that have come to our attention are listed below. Some of these were caught in page proof but not changed in the final publication. Corrections to scientific names follow those given in Eschmeyer (1998, Online). Some minor typographical errors that ...
Using a novel combination of palaeohabitat modelling and genetic mixture analyses, we identify an... more Using a novel combination of palaeohabitat modelling and genetic mixture analyses, we identify and assess a sea-level-driven recolonization process following the Last Glacial Maximum (LGM). Our palaeohabitat modelling reveals dramatic changes in estuarine habitat distribution along the coast of California (USA) and Baja California (Mexico). At the LGM (approx. 20 kya), when sea level was approximately 130 m lower, the palaeo-shoreline was too steep for tidal estuarine habitat formation, eliminating this habitat type from regions where it is currently most abundant, and limiting such estuaries to a northern and a southern refugium separated by 1000 km. We assess the recolonization of estuaries formed during post-LGM sea-level rise through examination of refugium-associated alleles and approximate Bayesian computation in three species of estuarine fishes. Results reveal sourcing of modern populations from both refugia, which admix in the newly formed habitat between the refuges. We in...
Revista Mexicana de Biodiversidad www.ib.unam.mx/revista/ Revista Mexicana de Biodiversidad 87 (2... more Revista Mexicana de Biodiversidad www.ib.unam.mx/revista/ Revista Mexicana de Biodiversidad 87 (2016) 390-398 Taxonomy and systematics Morphometric and meristic characterization of the endemic Desert chub Gila eremica (Teleostei: Cyprinidae), and its related congeners in Sonora, Mexico
Records of gray whales (Eschrichtius robustus) at and near their two known calving sites in the G... more Records of gray whales (Eschrichtius robustus) at and near their two known calving sites in the Gulf of California (Sea of Cortés), México, are reviewed up to 1995. The sites of Tojahui/Yavaros (Sonora) and Bahía Santa María (Sinaloa) represented the most distant calving grounds regularly visited by the species. Prior observations (mainly in the 1950s and 1960s) revealed relatively small but seasonally consistent numbers of whales, with maximum counts, including calves, of 30 individuals at Bahía Santa María in 1954, and 17-19 at Tojahui/Yavaros in 1955, 1963 and 1971. Observations (initiated in 1979) as well as interviews with longtime local residents and fishermen, document a decline in numbers and occupancy times of whales, especially cow/calf pairs, visiting these sites. In contrast, 19th century whaling records indicate that many more gray whales were found seasonally along these coasts. The recent decline, leading to the apparent disappearance, is likely to be due to human-ind...
Plate tectonics and sediment processes control regional continental shelf topography. We examine ... more Plate tectonics and sediment processes control regional continental shelf topography. We examine the genetic consequences of how glacial-associated sea-level change interacted with variable near-shore topography since the last glaciation. We reconstructed the size and distribution of areas suitable for tidal estuary formation from the Last Glacial Maximum, ~20 thousand years ago, to present from San Francisco, California, USA (~38 °N) to Reforma, Sinaloa, Mexico (~25 °N). We assessed range-wide genetic structure and diversity of three co-distributed tidal estuarine fishes (California Killifish, Shadow Goby, Longjaw Mudsucker) along ~4,600 km using mitochondrial control region and cytB sequence, and 16–20 microsatellite loci from a total of 524 individuals. Results show that glacial-associated sea-level change limited estuarine habitat to few, widely separated refugia at glacial lowstand, and present-day genetic clades were sourced from specific refugia. Habitat increased during postglacial sea-level rise and refugial populations admixed in newly formed habitats. Continental shelves with active tectonics and/or low sediment supply were steep and hosted fewer, smaller refugia with more genetically differentiated populations than on broader shelves. Approximate Bayesian computation favored the refuge-recolonization scenarios from habitat models over isolation by distance and seaway alternatives, indicating isolation at lowstand is a major diversification mechanism among estuarine (and perhaps other) coastal species. Because sea-level change is a global phenomenon, we suggest this top-down physical control of extirpation-isolation-recolonization may be an important driver of genetic diversification in coastal taxa inhabiting other topographically complex coasts globally during the Mid- to Late Pleistocene and deeper timescales
Mitochondrial evidence for a new evolutionary significant unit within the Gila eremica lineage (T... more Mitochondrial evidence for a new evolutionary significant unit within the Gila eremica lineage (Teleostei, Cyprinidae) in Sonora, Northwest Mexico. We present the phylogenetic affinities and DNA barcode of Gila cf. eremica, a geographically isolated and morphologically divergent population from G. eremica DeMarais, 1991. Mitochondrial phylogenetic analyses of cyt-b, cox1 and nd2 show a clades pattern within the G. eremica lineage, placing G. cf. eremica in a clade of specific identity to and sharing a putative common ancestor with G. eremica from the Mátape River basin. The barcoding analysis using a character-based approach of CAOS showed seven single pure characters discriminating G. eremica from its regional congener G. purpurea, and one fixed character in G. cf. eremica discriminating it from G. eremica. These results and the recent detection of diagnostic morphological differences between G. cf. eremica and G. eremica support the hypothesis of Gila cf. eremica as an significant evolutionary unit within the G. eremica lineage.
A review of published research indicates that the Northern Gulf of California is, historically an... more A review of published research indicates that the Northern Gulf of California is, historically and currently, one of the most biologically productive marine regions on Earth. This high productivity is driven by a unique mix of factors, including: coastal upwelling, wind-driven mixing, extreme tidal mixing and turbulence, thermohaline circulation that moves intermediate waters into the mixed layer, coastal-trapped waves, regular sediment resuspension, and, to a lesser extent, agricultural runoff, released nutrients from erosion of ancient Colorado River Delta
Conservación de truchas natives mexicanas y su descubrimiento, estatus, protección y redescubrimi... more Conservación de truchas natives mexicanas y su descubrimiento, estatus, protección y redescubrimiento de la trucha del Conchos, la primera especie nativa. i 1 DEAN A
Errors in Nelson et al. (2004) that have come to our attention are listed below. Some of these we... more Errors in Nelson et al. (2004) that have come to our attention are listed below. Some of these were caught in page proof but not changed in the final publication. Corrections to scientific names follow those given in Eschmeyer (1998, Online). Some minor typographical errors that ...
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