Ecology and evolution of sympatric sticklebacks (Gasterosteus): origin of the species pairs

1993 ◽  
Vol 71 (3) ◽  
pp. 515-523 ◽  
Author(s):  
J. D. McPhail

Pairs of plankton-feeding and benthos-foraging sticklebacks (Gasterosteus aculeatus) (limnetics and benthics) coexist in six small lakes in southwestern British Columbia. In spite of a persistent low level of hybridization the pairs maintain themselves as distinct genetic and ecological entities; because of this they are viewed as biological species. They appear to be restricted to the central Strait of Georgia region, and the geological history of the area argues that they are of postglacial origin. The pairs occur on three islands (Vancouver, Texada, and Lasqueti), but even on these islands they are not found in all available lakes. Both lake morphometry (size and depth) and altitude appear to influence local distribution. Hypotheses that might explain the origin of the pairs are examined. Neither theory nor data support a sympatric origin, but an allopatric origin through two invasions of marine sticklebacks is consistent with both the geological history of the area and the details of local distribution. An independent but parallel evolution of the pairs on at least two islands (Vancouver and Texada) is implicit in this hypothesis. The hypothesis also assumes that although the initial divergence started in allopatry, competitive interactions in sympatry played a major role in the evolution of reproductive isolation and resource partitioning.

1984 ◽  
Vol 62 (7) ◽  
pp. 1402-1408 ◽  
Author(s):  
J. D. McPhail

Two morphological forms of three-spined stickleback (Gasterosteus) coexist in Enos Lake near Nanoose Bay, Vancouver Island. For convenience, the two forms are referred to as "benthics" and "limnetics." Morphological and biochemical characteristics of the two forms were examined and artificial hybrids (F1 and F2) reared in the laboratory. The two forms differ in male nuptial colour, body shape, and gill raker architecture. These differences are inherited and have remained stable for several generations. Benthics and limnetics also differ in allele frequencies at three loci (Mdh-3, Ck, and Pgm). At one of these loci (Mdh-3) the limnetic form is polymorphic and the benthic form is fixed. Since the two forms maintain themselves as discrete entities and there is no evidence of gene flow, they are considered separate biological species. It is not certain that either of these species is Gasterosteus aculeatus. Similar species pairs exist in other lakes in the Strait of Georgia region but, at present, their relationship to the species pair in Enos Lake is unknown.


2000 ◽  
Vol 30 (3) ◽  
pp. 474-476 ◽  
Author(s):  
LUIZ JOSÉ TOMAZELLI ◽  
SÉRGIO REBELLO DILLENBURG ◽  
JORGE ALBERTO VILLWOCK

2018 ◽  
Vol 938 (8) ◽  
pp. 38-43
Author(s):  
S.A. Kotler ◽  
I.D. Zolnikov ◽  
D.V. Pchelnikov

The types of geological and geomorphological structure of the Katun valley are distinguished in the work. For this, a method of geoinformation mapping using morphometric indicators of the valley’s width and meandering of the channel was developed. The morphometric parameter of the valley’s width was calculated as the total area of terraces. As the morphometric parameters of the channel’s meandering, the angles of the river segments’ deviation relative to each other were calculated. Conjugated analysis of these morphometric indicators enabled identifying 18 morphotypes. These morphotypes according to the geological and geomorphological structure of the valley were combined into 4 classes. Separation of the Katun valley in certain classes and morphotypes is due to the different geological history of these sites during the Quaternary period. The most important reasons predetermining the modern variety of geological and geomorphological types of the valley are neotectonic movements and exogenous phenomena (glaciers, dam lakes, landslides, etc.) naturally localized in the space from the upstream of the river to its exit into the foothills. The developed method can be applied for quantitative morphometric classification of the mountain rivers’ valleys in other regions.


2016 ◽  
Author(s):  
Celine Martin ◽  
◽  
George E. Harlow ◽  
George E. Harlow ◽  
George E. Harlow ◽  
...  

2020 ◽  
Vol 190 (2) ◽  
pp. 709-736
Author(s):  
Jae-Cheon Sohn ◽  
Shigeki Kobayashi ◽  
Yutaka Yoshiyasu

Abstract A northward trans-Wallacean radiation is demonstrated for Chrysorthenches, a member of the Orthenches group. Here we review Chrysorthenches and allied genera resulting in a generic transfer of Diathryptica callibrya to Chrysorthenches and two new congeners: C. muraseaeSohn & Kobayashisp. nov. from Japan and C. smaragdinaSohnsp. nov. from Thailand. We review morphological characters of Chrysorthenches and allied genera, and find polyphyly of Diathryptica and the association of the Orthenches-group with Glyphipterigidae. These findings were supported in a maximum likelihood phylogeny of DNA barcodes from ten yponomeutoids. We analysed 30 morphological characters for 12 species of Chrysorthenches, plus one outgroup, via a cladistic approach. The resulting cladogram redefined two pre-existing Chrysorthenches species-groups and identified one novel lineage: the C. callibrya species-group. We review the host associations between Chrysorthenches and Podocarpaceae, based on mapping the working phylogenies. Our review suggests that ancestral Chrysorthenches colonized Podocarpus and later shifted to other podocarp genera. Biogeographical patterns of Chrysorthenches show that they evolved long after the Podocarpaceae radiation. Disjunctive trans-Wallacean distribution of the C. callibrya species-group is possibly related to the tracking of their host-plants and the complicated geological history of the island-arc system connecting Australia and East Asia.


The Lake Rudolf Rift Valley Expedition was designed to carry out many different lines of investigation in the Lake Rudolf Basin. One of the chief of these was a study of the geological history of that part of the East African Rift Valley. The expedition was assisted financially by The Royal Society, The Geological Society of London, The Royal Geographical Society, The Percy Sladen Trustees and the Geographical and Geological Sections of the British Association. A general description of the activities of the Expedition was given in a paper read before the Royal Geographical Society (Fuchs 1935). Owing to the tragic loss of two members of the expedition, Dr W. S. Dyson and Mr W. R. H. Martin, two fruitless months were spent searching for them. Consequently a great amount of the work planned for the east side of the lake had to be abandoned. Nevertheless, the considerable distance travelled within the 50,000 sq. miles of the Rudolf Basin has enabled me to make out the chief events of its geological history. I am very much indebted to all those who assisted us in the field and at home, in particular to the Kenya Government, the Officers of the King’s African Rifles, and Mr H. L. Sikes of the Public Works Department; I would also like to thank Mr A. M. Champion, Provincial Commissioner of Turkana, who wholeheartedly assisted us in every way possible both in the field and at home, for he has placed at my disposal his own excellent topographical maps and his extensive observations on the geology of the area. I am also deeply indebted to Professor O. T. Jones, Mr Henry Woods and Mr W. Campbell Smith for their criticisms. Mr Campbell Smith has also given me provisional identifications of the rocks.


1918 ◽  
Vol 37 ◽  
pp. 327-349 ◽  
Author(s):  
B. N. Peach ◽  
J. Horne ◽  
E. T. Newton

A characteristic feature of the plateau of Cambrian Limestone in the neighbourhood of Inchnadamff is the occurrence in it of swallow-holes, caves, and subterranean channels which are intimately associated with the geological history of the region. The valley of Allt nan Uamh (Burn of the Caves), locally known as the Coldstream Burn, furnishes striking examples of these phenomena. One of the caves in this valley yielded an interesting succession of deposits, from which were collected abundant remains of mammals and birds. The discovery of bones of the Northern Lynx, the Arctic Lemming, and the Northern Vole among these relics, and the collateral evidence of the materials forming some of these layers, seem to link the early history of this bone-cave with late glacial time, or at least with a period before the final disappearance of local glaciers in that region.


Zootaxa ◽  
2022 ◽  
Vol 5091 (4) ◽  
pp. 501-545
Author(s):  
YI-FENG ZHANG ◽  
LING-ZENG MENG ◽  
ROGER A. BEAVER

The powder post beetles (Coleoptera: Bostrichidae) (except Lyctinae) of Yunnan Province in Southwest China are reviewed for the first time. Keys to twenty-six genera and fifty-two species from the Yunnan region are provided. One new genus and seven new species are described: Dinoderus (Dinoderastes) hongheensis sp. nov., Dinoderus (Dinoderastes) nanxiheensis sp. nov., Gracilenta yingjiangensis gen. nov., sp. nov., Calonistes vittatus sp. nov., Calophagus colombiana sp. nov., Xylodrypta guochuanii sp. nov. and Xylodrypta zhenghei sp. nov.. Fourteen species are recorded in China for the first time. The bostrichid fauna of Yunnan is compared with those of the neighbouring bio-geographically related Southeast Asian and Himalayan regions. The fauna has a close affinity with that of tropical Southeast Asia and a much weaker relationship with the Palearctic region. The differences with the Himalayas may reflect the separate evolutionary and complex geological history of the two areas.


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