Geographic isolation facilitates the evolution of reproductive isolation and morphological divergence

The systematics of the subfamilies Salmoninae and Coregoninae of recently glaciated regions are reviewed. Interrelation between systematics and fisheries biology are stressed, pointing out the abundance of intraspecific genetic diversity of some salmonid fishes manifested in ecological and behavioral specializations, but not necessarily by morphological divergence. Innate, reproductive homing behavior of salmonid fishes may allow closely related populations to exist in sympatry and maintain reproductive isolation. Examples are cited to support the contention that many sympatric "sibling species" have evolved from a common ancestor in postglacial times. Closely related, sympatric populations are a major taxonomic problem, but this phenomenon which allows a species to consist of genetically discrete units with reproductive isolation between the stocks is of great significance for fisheries management. Postglacial salmonid communities are typically fragile and highly susceptible to disruption or destruction by introductions, eutrophication, and exploitation. Every effort should be made to protect the genetic diversity of a species.

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Selection and geographic isolation influence hummingbird speciation: genetic, acoustic and morphological divergence in the wedge-tailed sabrewing (Campylopterus curvipennis)

BMC Evolutionary Biology ◽

10.1186/1471-2148-11-38 ◽

2011 ◽

Vol 11 (1) ◽

Cited By ~ 59

Author(s):

Clementina González ◽

Juan Francisco Ornelas ◽

Carla Gutiérrez-Rodríguez

Keyword(s):

Morphological Divergence ◽

Geographic Isolation

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Reproductive isolation and morphological divergence between cryptic lineages of the copepod Acartia tonsa in Chesapeake Bay

Marine Ecology Progress Series ◽

10.3354/meps12569 ◽

2018 ◽

Vol 597 ◽

pp. 99-113 ◽

Cited By ~ 7

Author(s):

LV Plough ◽

C Fitzgerald ◽

A Plummer ◽

JJ Pierson

Keyword(s):

Reproductive Isolation ◽

Chesapeake Bay ◽

Acartia Tonsa ◽

Morphological Divergence

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Interpreting variability among isolates of Macrophomina phaseolina in pathogenicity, pycnidium production, and chlorate utilization

Canadian Journal of Botany ◽

10.1139/b95-172 ◽

1995 ◽

Vol 73 (10) ◽

pp. 1596-1603 ◽

Cited By ~ 62

Author(s):

J. D. Mihail ◽

S. J. Taylor

Keyword(s):

General Population ◽

Reproductive Isolation ◽

Key Words ◽

East Africa ◽

Initial Level ◽

Macrophomina Phaseolina ◽

Host Tissue ◽

Host Specialization ◽

Geographic Isolation ◽

Tissue Source

One hundred and fourteen isolates of Macrophomina phaseolina from tissue of hosts in the Asteraceae, Euphorbiaceae, Fabaceae, and Poaceae, and from cultivated and noncultivated soils in Somalia (east Africa) and Arizona were tested for pathogenicity, ability to form pycnidia, and chlorate-utilization phenotype. Hyphal interactions of pairs of isolates from noncultivated soils in Somalia and Arizona were examined to address the possibility of genetic reproductive isolation of two geographically separated populations. Isolates from the Poaceae were less pathogenic and formed pycnidia less frequently compared with isolates from dicot host tissue. Chlorate-utilization phenotype was unrelated to host tissue source. However, isolates that infrequently or never produced pycnidia were more likely to have chlorate-sensitive phenotypes. Apparently successful hyphal fusions were observed for 64.3% of confrontations where one isolate was taken from Arizona and one was from Somalia, implying no barrier to genetic interchange at this initial level of interaction. While M. phaseolina is a heterogeneous species that cannot be partitioned into distinct subspecific groups based upon function, it appears that isolates colonizing the Poaceae are more restricted in pathogenicity than the general population. Key words: chlorate utilization, geographic isolation, host specialization, hyphal interactions, Macrophomina phaseolina.

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Insular morphological divergence in the lizard Liolaemus pictus (Liolaemidae)

Amphibia-Reptilia ◽

10.1163/156853806776052146 ◽

2006 ◽

Vol 27 (1) ◽

pp. 103-111 ◽

Cited By ~ 17

Author(s):

Marco Méndez ◽

Alberto Veloso ◽

Marcela Vidal

Keyword(s):

Morphological Characters ◽

Lateral View ◽

Morphological Divergence ◽

Glacial Period ◽

Southern Chile ◽

Geographic Isolation ◽

Morphometric Data ◽

Head Shape ◽

Lizard Species ◽

Geometric Morphometric

AbstractLiolaemus pictus is a widely distributed arboreal lizard species in southern Chile. Within this species, mainland and island subspecies have been described mainly based on external morphological characters, however, their diagnostic characters have not been accurately demarcated. We used both traditional and geometric morphometrics to study the morphological divergence in L. pictus subspecies. Since geographic isolation can be related to environmental variation (e.g., variation in abundance and richness of insects or fruits), we predict that the L. pictus morphology could vary in head shape between mainland and island localities.Our results show morphological divergence in all variables analyzed among the island and mainland localities. The traditional morphometric approach reveals differences between populations from the mainland and island localities, where the mainland populations show a larger head size. Geometric morphometric data indicate that the eye orbits of the island specimens are more extended than in the mainland specimens in the dorsal view; this is probably related to a different capacity of substrate used. Also, in the lateral view, the eye orbits are extended and the head shape is less dorso-ventrally compressed in the island locality than in mainland populations and the terminal mouth position is more posterior in island specimens. We suggest that the morphological variation between mainland and island localities could be related to the fact that these populations were isolated during the last maximum glacial period in southern Chile, a period in which geomorphologic and bioclimatic features of this area were modified forming the present archipelago.

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