scholarly journals Embryo implantation during the short luteal phase of the corn mouse, Calomys musculinus, and the apparent lack of a lactational diapause in South American murid rodents

Reproduction ◽  
2001 ◽  
pp. 815-823 ◽  
Author(s):  
OL Buzzio ◽  
A Koninckx ◽  
NB Carreno ◽  
A Castro-Vazquez
Keyword(s):  
North American ◽  
Luteal Phase ◽  
Embryo Implantation ◽  
South American ◽  
Embryonic Diapause ◽  
South American Species ◽  
Apparent Lack ◽  
The North ◽  
Calomys Musculinus ◽  
Murid Rodents

As the corn mouse, Calomys musculinus, has a short luteal phase (2-3 days) that is not prolonged after copulation, it was hypothesized that (i) implantation would occur at the end of this phase, that is, earlier than it occurs in most murid species that have been studied, and (ii) a lactational embryonic diapause would not occur during the luteal phase. These hypotheses were tested in females that had copulated during postpartum oestrus and were either lactating or not lactating. Data were recorded from day 3 to day 5 of pregnancy (day 1 = day after coitus), at both 03:00-05:00 h and 17:00-19:00 h. Evidence of implantation in both non-lactating and lactating animals was apparent at 03:00-05:00 h on day 4 (endometrial 'blue reaction' in all cases and failure to recover free uterine embryos in some cases) and implantation swellings appeared within 24 h in both groups. In another experiment, the increase in duration of interbirth intervals in continuously mated females and their correlation with the number of suckling young were compared among C. musculinus, C. laucha, Akodon molinae (South American murid species) and Peromyscus maniculatus (a North American murid in which a lactational embryonic diapause has been shown). The results were indicative of a lactational embryonic diapause in the North American species, but not in the South American species. It was concluded that in C. musculinus (i) implantation occurs at the end of the spontaneous luteal phase, and (ii) that a lactational embryonic diapause does not occur: the absence of a lactational embryonic diapause may be common to other South American murid rodents.

CYTOTAXONOMIC STUDIES ON NEW WORLD SPECIES OF ANEMONE (SECTION ERIOCEPHALUS) WITH TUBEROUS ROOTSTOCKS

1966 ◽  
Vol 44 (7) ◽  
pp. 899-928 ◽  
Author(s):  
Cecily Joseph ◽  
Margaret Heimburger
Keyword(s):  
North American ◽  
New World ◽  
Diploid Species ◽  
Pollen Grain ◽  
South American ◽  
New Taxon ◽  
South American Species ◽  
The North ◽  
Additional Support ◽  
North And South

The American species of Anemone L. (section Eriocephalus Hook. f. & Thoms.) with tuberous rootstocks were studied by biosystematic methods. Anemone caroliniana Walt., A. heterophylla Nutt. ex Torr. & Gray, A. tuberosa Rydb., and A. edwardsiana Tharp (tentatively) are recognized from North America and A. decapetala Ard., A. triternata Vahl, and A. cicutifolia Johnst. from South America. Karyotypes of the diploid species (2n = 16), A. heterophylla, A. tuberosa, A. decapetala, and A. triternata are described. They resemble the karyotype of A. caroliniana published earlier. Anemone edwardsiana and A. cicutifolia are also presumed diploid from stomatal and pollen grain studies. A new taxon (2n = 32), of undecided status, was obtained from Chile. North American plants included by authors in A. decapetala are here referred to A. heterophylla. The North and South American species appear to form two separate groups, the species of each continent being more closely related among themselves than to those of the other continent. Fewer stomata, larger chromosome size, and higher DNA content are characteristic of the North American species. Additional support for the separation of the two groups derives from limited meiotic studies which indicate a larger number of inversion differences in inter- than in intra-continental hybrids.

Diversification of the North American Doellingeria-Eucephalus Clade (Astereae: Asteraceae) Inferred from Molecular and Morphological Evidence

2019 ◽  
Vol 44 (4) ◽  
pp. 930-942
Author(s):  
Geraldine A. Allen ◽  
Luc Brouillet ◽  
John C. Semple ◽  
Heidi J. Guest ◽  
Robert Underhill
Keyword(s):  
North American ◽  
Sequence Data ◽  
Phylogenetic Analyses ◽  
Sister Group ◽  
Morphological Evidence ◽  
South American ◽  
New Combinations ◽  
The North ◽  
Hybridization Event ◽  
Ancient Hybridization

Abstract—Doellingeria and Eucephalus form the earliest-diverging clade of the North American Astereae lineage. Phylogenetic analyses of both nuclear and plastid sequence data show that the Doellingeria-Eucephalus clade consists of two main subclades that differ from current circumscriptions of the two genera. Doellingeria is the sister group to E. elegans, and the Doellingeria + E. elegans subclade in turn is sister to the subclade containing all remaining species of Eucephalus. In the plastid phylogeny, the two subclades are deeply divergent, a pattern that is consistent with an ancient hybridization event involving ancestral species of the Doellingeria-Eucephalus clade and an ancestral taxon of a related North American or South American group. Divergence of the two Doellingeria-Eucephalus subclades may have occurred in association with northward migration from South American ancestors. We combine these two genera under the older of the two names, Doellingeria, and propose 12 new combinations (10 species and two varieties) for all species of Eucephalus.

No longer shipwrecked—Selkirkia (Boraginaceae) back on the mainland with generic rearrangements in South American “Omphalodes” based on molecular data

Phytotaxa ◽  
2016 ◽  
Vol 270 (4) ◽  
pp. 231 ◽  
Author(s):  
NORBERT HOLSTEIN ◽  
JULIANA CHACÓN ◽  
HARTMUT H. HILGER ◽  
MAXIMILIAN WEIGEND
Keyword(s):  
Type Species ◽  
Molecular Data ◽  
Taxon Sampling ◽  
South American ◽  
South American Species ◽  
European Species ◽  
The North ◽  
Genus 2 ◽  
Eurasian Species ◽  
Group 1

The genus Omphalodes (Boraginaceae) has recently been shown to be polyphyletic. Two distantly related lineages have already been segregated into the genera Memoremea (Central Europe) and Nihon (East Asia), respectively. We expanded the taxon sampling in the Omphalodeae and confirm that the genus is still paraphyletic to the two monotypic genera Selkirkia from the Juan Fernández Islands off the coast of Chile and Myosotidium from Chatham Island off the coast of New Zealand, plus two South American species currently assigned to Cynoglossum, and one species recently segregated from the latter genus as Mapuchea. Four clades are retrieved in a narrowly delimited Omphalodes group: 1) Iberodes, the annual southwestern European species of Omphalodes s.l. that have been recently segregated into this genus, 2) Omphalodes s.str., perennial western Eurasian species (including the type species of the genus), 3) the North American species of Omphalodes, and 4) the southern hemispheric Myosotidium as sister to a monophyletic group with Mapuchea plus the two other South American species of “Cynoglossum” and the island shrub Selkirkia berteroi. We argue that the taxa of this latter clade are best placed into an expanded genus Selkirkia. Selkirkia then represents a morphologically coherent entity with glochidiate nutlets. Its considerable difference in vegetative morphology to Myosotidium is easily explained by the highly divergent habitats the respective plants occupy. Lectotypifications, illustrations, and descriptions are provided for Myosotidium and the species of the expanded genus Selkirkia.

ON THE GEOGRAPHICAL DISTRIBUTION OF NORTH AMERICAN LEPIDOPTERA

1886 ◽  
Vol 18 (11) ◽  
pp. 213-220
Author(s):  
Aug. R. Grote
Keyword(s):  
Geographical Distribution ◽  
North American ◽  
North American Species ◽  
South American ◽  
Seasonal Temperature ◽  
The South ◽  
Old World ◽  
The North

Again, the genera Citheronia and Eacles are a South American element in our fauna, while the typical Attacinæ, such as Actias, probably belong to the Old World element in our fauna, together with all our Platypteryginœ. Among the Hawk Moths the genera Philampelus and Phlegethontius are of probable South American extraction, though represented now by certain strictly North American species. Mr. Robert Bunker, writing from Rochester, N. Y., records the fact that Philampelus Pandorus, going into chrysaiis Augnst 1, came out Sept. 10 as a moth, showing that in a warmer climate the species would become doublebrooded. And this is undoubtedly the case with many species the farther we go South, where insect activities are not interrupted so long and so strictly by the cold of winter. Since the continuance of the pupal condition is influenced by cold, a diminishing seasonal temperature for ages may have originally affected, if not induced, the transformations of insects as a whole. Butterflies and Moths which are single brooded in the North become double brooded in the South.

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