scholarly journals An Evolutionary Study of Carex Subg. Psyllophorae (Cyperaceae) Sheds Light on a Strikingly Disjunct Distribution in the Southern Hemisphere, With Emphasis on Its Patagonian Diversification

2021 ◽  
Vol 12 ◽  
Author(s):  
Carmen Benítez-Benítez ◽  
Ana Otero ◽  
Kerry A. Ford ◽  
Pablo García-Moro ◽  
Sabina Donadío ◽  
...  

Carex subgenus Psyllophorae is an engaging study group due to its early diversification compared to most Carex lineages, and its remarkable disjunct distribution in four continents corresponding to three independent sections: sect. Psyllophorae in Western Palearctic, sect. Schoenoxiphium in Afrotropical region, and sect. Junciformes in South America (SA) and SW Pacific. The latter section is mainly distributed in Patagonia and the Andes, where it is one of the few Carex groups with a significant in situ diversification. We assess the role of historical geo-climatic events in the evolutionary history of the group, particularly intercontinental colonization events and diversification processes, with an emphasis on SA. We performed an integrative study using phylogenetic (four DNA regions), divergence times, diversification rates, biogeographic reconstruction, and bioclimatic niche evolution analyses. The crown age of subg. Psyllophorae (early Miocene) supports this lineage as one of the oldest within Carex. The diversification rate probably decreased over time in the whole subgenus. Geography seems to have played a primary role in the diversification of subg. Psyllophorae. Inferred divergence times imply a diversification scenario away from primary Gondwanan vicariance hypotheses and suggest long-distance dispersal-mediated allopatric diversification. Section Junciformes remained in Northern Patagonia since its divergence until Plio-Pleistocene glaciations. Andean orogeny appears to have acted as a northward corridor, which contrasts with the general pattern of North-to-South migration for temperate-adapted organisms. A striking niche conservatism characterizes the evolution of this section. Colonization of the SW Pacific took place on a single long-distance dispersal event from SA. The little ecological changes involved in the trans-Pacific disjunction imply the preadaptation of the group prior to the colonization of the SW Pacific. The high species number of the section results from simple accumulation of morphological changes (disparification), rather than shifts in ecological niche related to increased diversification rates (radiation).

1979 ◽  
Vol 57 (20) ◽  
pp. 2179-2225 ◽  
Author(s):  
Rudolf M. Schuster

The dispersal of a considerable number, if not the vast majority, of southern hemisphere Hepaticae chiefly belonging to "old" families and suborders can be visualized as resulting primarily from short-range or "step-wise" dispersal, as part of structural communities, before the final disassembly of the presently fragmented Gondwanaland. Often with the disruption of gene flow, disjunct populations of once continuously distributed Gondwanalandic taxa have undergone speciation, in most cases as physical disruption occurred. Significant relict and disjunct distribution patterns for 21 hepatic taxa are mapped and discussed. A discussion of (i) rate of speciation and genus formation, (ii) efficiency of long-distance dispersal, and (iii) the geological background is presented with the purpose of explaining the origins of antipodal distribution patterns within the Hepaticae.


2020 ◽  
Vol 2 (3) ◽  
Author(s):  
Rory Hodd ◽  
Fred Rumsey

The occurrence of the fern Stenogrammitis myosuroides (Sw.) Labiak in Europe is reported for the first time. A small population was discovered on two boulders beside a stream in Atlantic oak woodland in the Killarney National Park, Co. Kerry, in southwest Ireland. The main identification features of this taxa and features that distinguish it from other similar taxa are laid out and discussed. S. myosuroides is elsewhere known to occur in the Neotropics, in Cuba, Jamaica and the Dominican Republic, and is thought to have colonised its Irish site through long-distance spore dispersal. Two Grammitid species of similar ecology have been discovered in the Azores in the past five decades and a number of bryophyte species share a similar disjunct distribution between Ireland and the Neotropics, all of which supports the theory that long-distance dispersal is the most plausible explanation for the occurrence of S. myosuroides in Ireland. It is not clear how long S. myosuroides has been present in Ireland, although morphological differences suggest that it may have been separated from the Neotropical populations for a long period. However, molecular analysis is required to elucidate this.


2021 ◽  
Vol 46 (4) ◽  
pp. 998-1010
Author(s):  
Javier Jauregui-Lazo ◽  
Daniel Potter

Abstract— Acaena (Rosaceae) is the most complex and ecologically variable genus in Sanguisorbinae. Although it has been the subject of several taxonomic treatments, the largest phylogenetic analysis to date only sampled a small fraction of the total global diversity (five to seven out of 45 to 50 species). This study included most of the species to elucidate the phylogenetic relationships of Acaena and biogeographic patterns in Sanguisorbinae. Phylogenetic analyses of non-coding nuclear (ITS region) and chloroplast (trnL-F) DNA sequence markers using maximum likelihood and Bayesian analyses suggested that Acaena is a paraphyletic group with species of Margyricarpus and Tetraglochin nested within it. We identified strong support for eight subclades that are geographically or taxonomically structured. Nevertheless, the species-level relationships within subclades are still uncertain, which may be due to rapid diversification and lack of informative characters in the markers used. Sanguisorbinae, a primarily Southern Hemisphere clade, exhibits a classic Gondwana disjunct distribution. This current distribution is explained primarily by eight long-distance dispersal events. Our results suggested that Sanguisorbinae split into Cliffortia and Acaena around 13.6 mya. While Cliffortia diversified in southern South Africa, Acaena experienced several migration events in the Southern Hemisphere. Our estimation of the ancestral range suggested that Acaena likely originated in South Africa, followed by migration and subsequent diversification into southern South America. From there, the genus migrated to New Zealand, throughout the Andes, and to tropical areas in Central America, reaching as far north as California. Chile and New Zealand are the main sources of propagules for dispersal as well as the greatest diversity for the genus. The evolutionary relationships of species in Acaena combine a history of rapid diversifications, long-distance dispersals, and genetic variation within some taxa. Further research should be undertaken to clarify the infraspecific classification of A. magellanica.


2020 ◽  
Vol 130 (3) ◽  
pp. 480-496
Author(s):  
Ana Sofia Bartolomeu Rodrigues ◽  
Anabela Martins ◽  
César Augusto Garcia ◽  
Cecília Sérgio ◽  
Ron Porley ◽  
...  

Abstract The ‘Rand flora’ is a biogeographical disjunction which refers to plant lineages occurring at the margins of the African continent and neighbouring oceanic archipelagos. Here, we tested whether the phylogeographical pattern of Exormotheca pustulosa Mitt. was the result of vicariance induced by past climatic changes or the outcome of a series of recent long-distance dispersal events. Two chloroplast markers (rps4-trnF region and psbA-trnH spacer) and one nuclear marker (ITS2) were analysed. Phylogenetic and phylogeographical relationships were inferred as well as divergence time estimates and ancestral areas. Exormotheca possibly originated in Eastern Africa during the Late Oligocene/Early Miocene while Exormotheca putulosa diversified during the Late Miocene. Three main E. pustulosa groups were found: the northern Macaronesia/Western Mediterranean, the South Africa/Saint Helena and the Cape Verde groups. The major splits among these groups occurred during the Late Miocene/Pliocene; diversification was recent, dating back to the Pleistocene. Climate-driven vicariance and subsequent long-distance dispersal events may have shaped the current disjunct distribution of E. pustulosa that corresponds to the Rand Flora pattern. Colonization of Macaronesia seems to have occurred twice by two independent lineages. The evolutionary history of E. pustulosa populations of Cape Verde warrants further study.


1995 ◽  
Vol 10 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Claudio Delgadillo M.

North and South America share about 675 species that show two basic patterns, namely, those with a continuous range and those with a disjunct distribution. Both may have resulted from step-bystep migration, but the latter, including 118 species, may be due to break up of previous distributions by post-Tertiary tectonic and climatic changes or by long-distance dispersal.


2020 ◽  
Author(s):  
Thaís Elias Almeida ◽  
Alexandre Salino ◽  
Jean-Yves Dubuisson ◽  
Sabine Hennequin

AbstractThe epiphytic fern genus Microgramma (Polypodiaceae) comprises 30 species occurring mainly in the Neotropics with one species in Africa, being an example of trans-Atlantic disjunction. Morphologically and ecologically, Microgramma presents a wide variation that is not seen in its closest related genera. Recent works changed the circumscription of Microgramma to better conform with phylogenetic evidence, but no comprehensively sampled study has addressed the evolution of this lineage. This study aimed to investigate phylogenetic relationships, ecological and morphological evolution within Microgramma, as well as test the role of long-distant dispersal in the history of the genus. Sequences from five plastid regions were used to infer the phylogenetic relationships and estimate divergence times. Our results show five clades in Microgramma that do not corroborate any infrageneric classification system proposed. Several morphological traits seem to be homoplastic, such as leaf dimorphism. Tuber-like myrmecodomatia are suggested to be synapomorphic for one clade, although ant-plant association appears in two distinct lineages. Microgramma lycopodioides and M. mauritiana are not closely related, with the African species nested within an Atlantic Forest clade, indicating a long-distance dispersal event estimated to have occurred around 15 Ma from South America to Africa, followed by speciation.


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