Distribution and phylogeny of glacier ice worms (Mesenchytraeus solifugus and Mesenchytraeus solifugus rainierensis)

2005 ◽  
Vol 83 (9) ◽  
pp. 1206-1213 ◽  
Author(s):  
Paula L Hartzell ◽  
Jefferson V Nghiem ◽  
Kristina J Richio ◽  
Daniel H Shain

Glacier ice worms, Mesenchytraeus solifugus (Emery, 1898) and Mesenchytraeus solifugus rainierensis Welch, 1916 (Enchytraeidae), are the only known oligochaetes adapted to life in ice. We have collected ice worm specimens from over 100 populations throughout the Pacific northwestern region of North America. Their current range extends ~2500 km along the Pacific coastline between south-central Alaska and central Oregon, with most populations occurring on relatively low-elevation, temperate glaciers. Phylogenetic analyses utilizing partial nuclear 28S rDNA and mitochondrial cytochrome c oxidase subunit I (COI) loci revealed the presence of two geographically distinct clades (northern and southern). The northern clade comprises all Alaskan populations, while the southern clade contains British Columbia, Washington State, and Oregon State populations. No evidence of gene flow was detected between these two lineages or between noncontiguous glaciers throughout their geographic range. Our results suggest that the mechanism of ice worm dispersal is primarily active, though at least one episode of passive dispersal is noted at the southern extent of their range.

2017 ◽  
Vol 284 (1864) ◽  
pp. 20171081 ◽  
Author(s):  
Shirley A. Lang ◽  
Naim Saglam ◽  
Joseph Kawash ◽  
Daniel H. Shain

Segmented worms (Annelida) are among the most successful animal inhabitants of extreme environments worldwide. An unusual group of enchytraeid oligochaetes of genus Mesenchytraeus are abundant in the Pacific northwestern region of North America and occupy geographically proximal ecozones ranging from low elevation rainforests and waterways to high altitude glaciers. Along this altitudinal transect, Mesenchytraeus representatives from disparate habitat types were collected and subjected to deep mitochondrial and nuclear phylogenetic analyses. Our data identify significant topological discordance among gene trees, and near equivalent interspecific divergence levels indicative of a rapid radiation event. Collectively, our results identify a Mesenchytraeus ‘explosion’ coincident with mountain building in the Pacific northwestern region that gave rise to closely related aquatic, ice, snow and terrestrial worms.


Zootaxa ◽  
2018 ◽  
Vol 4504 (1) ◽  
pp. 1 ◽  
Author(s):  
MARINA F. MCCOWIN ◽  
GREG W. ROUSE

Lamellibrachia Webb, 1969 has eight currently recognized species reported from chemosynthetic environments in the Pacific, Atlantic, and Mediterranean. Of these, Lamellibrachia barhami Webb, 1969 has been reported in the eastern Pacific from Canada to Costa Rica. In this study, phylogenetic analyses of Lamellibrachia tubeworms sampled from the Costa Rica margin confirm the large geographic range of L. barhami and reveal a new Lamellibrachia species from a single methane seep between 999 and 1,040 meters. Lamellibrachia donwalshi sp. nov. differs genetically and morphologically from all congeneric species. Despite its geographic proximity to the eastern Pacific L. barhami, L. donwalshi sp. nov. formed a clade with Atlantic and Mediterranean Lamellibrachia species. This suggests a vicariant event may have occurred after an Atlantic radiation of Lamellibrachia. 


2002 ◽  
Vol 80 (10) ◽  
pp. 1078-1087 ◽  
Author(s):  
George E Mustoe

Middle Eocene lacustrine deposits in south-central British Columbia and north-central Washington state preserve two types of Ginkgo leaves. A morphotype characterized by deeply divided multiple lobes is herein described as Ginkgo dissecta sp.nov. Leaves that are either undivided or shallowly divided into bilobate symmetry are indistinguishable from foliage of extant Ginkgo biloba Linnaeus. These fossils contradict the widely held belief that only a single Ginkgo species, Ginkgo adiantoides (Unger) Heer, inhabited Cenozoic forests.Key words: British Columbia, Eocene, fossil, Ginkgo adiantoides, Ginkgo biloba, Ginkgo dissecta, McAbee, Republic, Tertiary, Washington.


1975 ◽  
Vol 12 (3) ◽  
pp. 489-502 ◽  
Author(s):  
J. A. Westgate ◽  
R. J. Fulton

The Olympia interglacial sediments in the Interior Plateau region of British Columbia contain several thin, fine-grained rhyolitic and dacitic tephras, which undoubtedly represent the distal portions of widespread air-fall eruptive units. Successful discrimination of these tephras can be made by their mineral assemblage and composition of glass, magnetite and ilmenite, as determined by use of an electron microprobe; positive identification is not possible solely on the basis of field criteria such as coloration, degree of weathering, granulometry, thickness and stratigraphic position.Each tephra layer serves as a valuable time-parallel stratigraphic marker because of its regional extent and distinctive character. Those documented in this study include, in order of increasing age: Rialto Creek tephra, about 20 000 years old; Cherryville tephra, about 25 000 years old; Riggins Road tephra, about 30 000 years old; Duncan Lake tephra, about 34 000 years old; Dufferin Hill and Sweetsbridge tephras are probably close in age to Duncan Lake tephra; Kamloops Lake tephra is slightly older than 34 000 years; Mission Flats tephra is probably older than 35 000 years; Coutlee tephra is more than 37 000 years old; and the exact age of Okanagan Centre tephra is unknown. Such a detailed tephrochronological record should greatly facilitate geochronological and correlation studies of Olympia interglacial sediments in south-central British Columbia and adjacent areas of the Pacific Northwest.No definitive statement can be made at present on the identity of source volcanoes, but it is very likely that the commungtonite-rich tephras are derived from Mount St. Helens in Washington State.


2021 ◽  
Vol 95 ◽  
Author(s):  
B. Neov ◽  
G.P. Vasileva ◽  
G. Radoslavov ◽  
P. Hristov ◽  
D.T.J. Littlewood ◽  
...  

Abstract The aim of the study is to test a hypothesis for the phylogenetic relationships among mammalian hymenolepidid tapeworms, based on partial (D1–D3) nuclear 28S ribosomal RNA (rRNA) genes, by estimating new molecular phylogenies for the group based on partial mitochondrial cytochrome c oxidase I (COI) and nuclear 18S rRNA genes, as well as a combined analysis using all three genes. New sequences of COI and 18S rRNA genes were obtained for Coronacanthus integrus, C. magnihamatus, C. omissus, C. vassilevi, Ditestolepis diaphana, Lineolepis scutigera, Spasskylepis ovaluteri, Staphylocystis tiara, S. furcata, S. uncinata, Vaucherilepis trichophorus and Neoskrjabinolepis sp. The phylogenetic analyses confirmed the major clades identified by Haukisalmi et al. (Zoologica Scripta 39: 631–641, 2010): Ditestolepis clade, Hymenolepis clade, Rodentolepis clade and Arostrilepis clade. While the Ditestolepis clade is associated with soricids, the structure of the other three clades suggests multiple evolutionary events of host switching between shrews and rodents. Two of the present analyses (18S rRNA and COI genes) show that the basal relationships of the four mammalian clades are branching at the same polytomy with several hymenolepidids from birds (both terrestrial and aquatic). This may indicate a rapid radiation of the group, with multiple events of colonizations of mammalian hosts by avian parasites.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Manokaran Kamalakannan ◽  
Chandrakasan Sivaperuman ◽  
Shantanu Kundu ◽  
Govindarasu Gokulakrishnan ◽  
Chinnadurai Venkatraman ◽  
...  

AbstractWe discovered a new Crocidura species of shrew (Soricidae: Eulipotyphla) from Narcondam Island, India by using both morphological and molecular approaches. The new species, Crocidura narcondamica sp. nov. is of medium size (head and body lengths) and has a distinct external morphology (darker grey dense fur with a thick, darker tail) and craniodental characters (braincase is rounded and elevated with weak lambdoidal ridges) in comparison to other close congeners. This is the first discovery of a shrew from this volcanic island and increases the total number of Crocidura species catalogued in the Indian checklist of mammals to 12. The newly discovered species shows substantial genetic distances (12.02% to 16.61%) to other Crocidura species known from the Indian mainland, the Andaman and Nicobar Archipelago, Myanmar, and from Sumatra. Both Maximum-Likelihood and Bayesian phylogenetic inferences, based on mitochondrial (cytochrome b) gene sequences showed distinct clustering of all included soricid species and exhibit congruence with the previous evolutionary hypothesis on this mammalian group. The present phylogenetic analyses also furnished the evolutionary placement of the newly discovered species within the genus Crocidura.


Zootaxa ◽  
2011 ◽  
Vol 2918 (1) ◽  
pp. 15 ◽  
Author(s):  
I. WESLEY GAPP ◽  
BRUCE S. LIEBERMAN ◽  
MICHAEL C. POPE ◽  
KELLY A. DILLIARD

The Early Cambrian olenelline trilobites are a diverse clade and have been the subject of several phylogenetic analyses. Here, three new species of Bradyfallotaspis Fritz, 1972 (B. coriae, B. nicolascagei, and B. sekwiensis) and one new species of Nevadia Walcott, 1910 (N. saupeae) are described from the Sekwi Formation of the Mackenzie Mountains, Northwest Territories, Canada. In addition, new specimens potentially referable to Nevadia ovalis McMenamin, 1987 were recovered that may expand that species’ geographic range, which was thought to be restricted to Sonora, Mexico. The results of a phylogenetic analysis incorporating several olenelline taxa, including Judomia absita Fritz, 1973 from the Sekwi Formation, are also presented herein. This species has been assigned to various olenelline genera, including Judomia Lermontova, 1951 and Paranevadella Palmer & Repina, 1993. Phylogenetic analysis suggests this species is closely related to Judomia tera Lazarenko, 1960 from Siberia. This phylogenetic relationship provides further support for the hypothesis that a close biogeographic relationship existed between Laurentia and Siberia during the Cambrian.


2006 ◽  
Vol 120 (2) ◽  
pp. 163
Author(s):  
George W. Douglas ◽  
Jenifer L. Penny ◽  
Ksenia Barton

In Canada, Dwarf Woolly-heads, Psilocarphus brevissimus var. brevissimus, is restricted to the Similkameen River valley, south of Princeton in southwestern British Columbia and the extreme southeast and southwest corners of Alberta and Saskatchewan, respectively. This paper deals with the three British Columbia populations which represent the northwestern limit of the species which ranges from south-central British Columbia, southward in the western United States to Montana, Idaho, Washington, Oregon, Nevada, Utah, Wyoming, California and Baja California, Mexico. In British Columbia, P. brevissimus is associated with calcareous vernal pools and ephemeral pond edges in large forest openings. This habitat is rare in the area the few existing populations could easily be extirpated or degraded through slight changes in groundwater levels, coalbed methane gas drilling, housing development or recreational vehicles.


2017 ◽  
Vol 4 (4) ◽  
pp. 170105 ◽  
Author(s):  
Karen L. Bell ◽  
Haripriya Rangan ◽  
Manuel M. Fernandes ◽  
Christian A. Kull ◽  
Daniel J. Murphy

Acacia s.l. farnesiana , which originates from Mesoamerica, is the most widely distributed Acacia s.l. species across the tropics. It is assumed that the plant was transferred across the Atlantic to southern Europe by Spanish explorers, and then spread across the Old World tropics through a combination of chance long-distance and human-mediated dispersal. Our study uses genetic analysis and information from historical sources to test the relative roles of chance and human-mediated dispersal in its distribution. The results confirm the Mesoamerican origins of the plant and show three patterns of human-mediated dispersal. Samples from Spain showed greater genetic diversity than those from other Old World tropics, suggesting more instances of transatlantic introductions from the Americas to that country than to other parts of Africa and Asia. Individuals from the Philippines matched a population from South Central Mexico and were likely to have been direct, trans-Pacific introductions. Australian samples were genetically unique, indicating that the arrival of the species in the continent was independent of these European colonial activities. This suggests the possibility of pre-European human-mediated dispersal across the Pacific Ocean. These significant findings raise new questions for biogeographic studies that assume chance or transoceanic dispersal for disjunct plant distributions.


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