Overview of the generic status of Acacia (Leguminosae: Mimosoideae)

2003 ◽  
Vol 16 (1) ◽  
pp. 1 ◽  
Author(s):  
B. R. Maslin ◽  
J. T. Miller ◽  
D. S. Seigler

The systematic treatment and circumscription of the group of plants presently recognised as the genus Acacia has a complex history. The genus was first described by Philip Miller in 1754 and until 1842, when George Bentham clearly defined it's generic limits (by restricting the name Acacia to mimosoid plants having numerous free stamens), a number of species which are now referable to genera within tribes Ingeae and Mimoseae had been referred to it. As presently defined, Acacia is a cosmopolitan genus containing in excess of 1350 species and together with the monotypic genus Faidherbia Chev. (which occurs in Africa and the Middle East), comprises tribe Acacieae within subfamily Mimosoideae. The current classification of Acacia views the genus as comprising three large subgenera, namely subg. Acacia (c. 161 species, pantropical), subg. Aculeiferum Vassal (235 species; pantropical) and subg. Phyllodineae (DC.) Seringe (syn. subg. Heterophyllum Vassal) (960 species, largely confined to Australia). In 1986, Pedley proposed that these three subgenera be attributed generic rank, namely Acacia, Senegalia Rafinesque and Racosperma C.Martius, respectively, but this proposal was not widely adopted. Subsequently, the results of monographic and floristic works have greatly expanded knowledge, not only of Acacia, but also of its presumed relatives in tribes Ingeae and Mimoseae. Cladistic analyses of chloroplast genes have been especially informative in developing a better understanding of phylogenetic relationships of the group. The new data clearly show that the genus as presently defined (i.e. Acacia sens. lat.) is not monophyletic. Furthermore, five separate monophyletic groups can be recognised within Acacia sens. lat. and it is recommended that these each be recognised as a distinct genus. The five genera correspond to those recognised by Pedley, except that Senegalia sens. lat. is now regarded as comprising three genera, namely Senegalia sens. str., Acaciella Britton & Rose [based on Acacia subg. Aculeiferum sect. Filicinae (Benth.) Pedley] and an undescribed genus based on a group of species related to Acacia coulteri Benth. Acacia subg. Acacia appears to be located in tribe Mimoseae. The relationships of subg. Phyllodineae, subg. Aculeiferum sens. str., sect. Filicinae, the 'Acacia coulteri' group and Faidherbia are not fully resolved, although in all studies these groups are shown to be monophyletic. Although it is appropriate that each be recognised as a distinct genus, the application of the names Acacia and Racosperma is currently under consideration and it is therefore not appropriate to use these names until this matter is resolved.

2020 ◽  
Vol 5 (1) ◽  
pp. 17-38 ◽  
Author(s):  
K. Seto ◽  
S. Van Den Wyngaert ◽  
Y. Degawa ◽  
M. Kagami

During the last decade, the classification system of chytrids has dramatically changed based on zoospore ultrastructure and molecular phylogeny. In contrast to well-studied saprotrophic chytrids, most parasitic chytrids have thus far been only morphologically described by light microscopy, hence they hold great potential for filling some of the existing gaps in the current classification of chytrids. The genus Zygorhizidium is characterized by an operculate zoosporangium and a resting spore formed as a result of sexual reproduction in which a male thallus and female thallus fuse via a conjugation tube. All described species of Zygorhizidium are parasites of algae and their taxonomic positions remain to be resolved. Here, we examined morphology, zoospore ultrastructure, host specificity, and molecular phylogeny of seven cultures of Zygorhizidium spp. Based on thallus morphology and host specificity, one culture was identified as Z. willei parasitic on zygnematophycean green algae, whereas the others were identified as parasites of diatoms, Z. asterionellae on Asterionella, Z. melosirae on Aulacoseira, and Z. planktonicum on Ulnaria (formerly Synedra). According to phylogenetic analysis, Zygorhizidium was separated into two distinct order-level novel lineages; one lineage was composed singly of Z. willei, which is the type species of the genus, and the other included the three species of diatom parasites. Zoospore ultrastructural observation revealed that the two lineages can be distinguished from each other and both possess unique characters among the known orders within the Chytridiomycetes. Based on these results, we accommodate the three diatom parasites, Z. asterionellae, Z. melosirae, and Z. planktonicum in the distinct genus Zygophlyctis, and propose two new orders: Zygorhizidiales and Zygophlyctidales.


Author(s):  
Richard E. Young ◽  
Michael Vecchione ◽  
Heather E. Braid

A recent paper on the phylogenetic relationships of species within the cephalopod family Mastigoteuthidae made great progress in stabilizing the classification of the family. The authors, however, left the generic placement of Mastigoteuthis pyrodes unresolved. This problem is corrected here by placing this species in a new monotypic genus, Mastigotragus, based on unique structures of the photophores and the funnel/mantle locking apparatus.


Zootaxa ◽  
2005 ◽  
Vol 975 (1) ◽  
pp. 1 ◽  
Author(s):  
SHAUN L. WINTERTON ◽  
MARK A. METZ

An unusual new genus of Scenopinidae is described and figured from Namibia. Cyrtosathe kirkspriggsi gen. et sp. nov., represents the first record of a non-scenopinine window fly from subSaharan Africa. This monotypic genus does not fit well into the current classification of Scenopinidae and is likely an intermediate form between the subfamilies Proratinae and Scenopininae. The phylogenetic position of Cyrtosathe kirkspriggsi gen. et sp. nov. is discussed with respect to previous studies on Scenopinidae relationships and classification.


1993 ◽  
Vol 71 (3) ◽  
pp. 393-407 ◽  
Author(s):  
Jinliang Li ◽  
I. Brent Heath ◽  
Laurence Packer

We investigated the phylogenetic relationships of the Chytridiomycota and the chytridiomycetous gut fungi with a cladistic analysis of 42 morphological, ultrastructural, and mitotic characters for 38 taxa using both maximum parsimony and distance algorithms. Our analyses show that there are three major clades within the Chytridiomycota: the gut fungi, the Blastocladiales, and the Spizellomycetales–Chytridiales–Monoblepharidales. Consequently, we elevated the gut fungi to the order Neocallimasticales ord.nov. Our results suggest that a modified Chytridiales, including the Monoblepharidales, is a monophyletic group. In contrast the Spizellomycetales are paraphyletic because the Chytridiales arose within them. The separation of the traditional Chytridiales into two orders is thus doubtful. Although the Blastocladiales are closer to members of the Spizellomycetales than the Chytridiales, the cladistic analyses of both structural and rRNA sequence data do not support the idea that the Blastocladiales were derived from the Spizellomycetales. We suggest emendations to the classification of the Chytridiomycota and note which groupings require further analysis. Our phylogeny for the currently recognized species of gut fungi is inconsistent with the existing classification. Nonetheless, pending further investigations, we prefer to retain the existing, easily defined genera for which a key is provided. Key words: Chytridiomycota, rumen fungi, phylogeny, morphology, ultrastructure, mitosis.


2020 ◽  
Vol 5 (1) ◽  
pp. 243-251
Author(s):  
Akira Horibata ◽  
Tsuneo Kato

AbstractA total of 145 accessions of the genus Citrus and related genera, maintained in the Conservation Garden for Citrus Germplasm at the Experimental Farm of Kindai University, Yuasa, Wakayama, Japan, were examined for their phylogenetic relationships. The present classification was conducted using an inter-retrotransposon amplified polymorphism (IRAP) method based on the insertion polymorphism of a retrotransposon, CIRE1, identified in C. sinensis. The objective of this study was to evaluate the applicability of the IRAP method for citrus classification. The constructed dendrogram showed that the 145 accessions and two outgroup species were successfully classified into five major clades. A large number of C. sinensis accessions were divided into three traditional groups, navel orange, sweet orange, and blood orange, almost corresponding to the sub-clades in the dendrogram. Several other accessions belonging to the same species, and also many hybrid cultivars from crossbreeding, were localized into the respective sub-clades or near positions in the dendrogram. Several unclassified accessions could also be located in the dendrogram, suggesting novel relationships with other accessions. It was concluded that the IRAP method based on CIRE1 insertion polymorphism was suitable for the classification of citrus from a molecular point of view.


BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Joonhyung Jung ◽  
Changkyun Kim ◽  
Joo-Hwan Kim

Abstract Background Commelinaceae (Commelinales) comprise 41 genera and are widely distributed in both the Old and New Worlds, except in Europe. The relationships among genera in this family have been suggested in several morphological and molecular studies. However, it is difficult to explain their relationships due to high morphological variations and low support values. Currently, many researchers have been using complete chloroplast genome data for inferring the evolution of land plants. In this study, we completed 15 new plastid genome sequences of subfamily Commelinoideae using the Mi-seq platform. We utilized genome data to reveal the structural variations and reconstruct the problematic positions of genera for the first time. Results All examined species of Commelinoideae have three pseudogenes (accD, rpoA, and ycf15), and the former two might be a synapomorphy within Commelinales. Only four species in tribe Commelineae presented IR expansion, which affected duplication of the rpl22 gene. We identified inversions that range from approximately 3 to 15 kb in four taxa (Amischotolype, Belosynapsis, Murdannia, and Streptolirion). The phylogenetic analysis using 77 chloroplast protein-coding genes with maximum parsimony, maximum likelihood, and Bayesian inference suggests that Palisota is most closely related to tribe Commelineae, supported by high support values. This result differs significantly from the current classification of Commelinaceae. Also, we resolved the unclear position of Streptoliriinae and the monophyly of Dichorisandrinae. Among the ten CDS (ndhH, rpoC2, ndhA, rps3, ndhG, ndhD, ccsA, ndhF, matK, and ycf1), which have high nucleotide diversity values (Pi > 0.045) and over 500 bp length, four CDS (ndhH, rpoC2, matK, and ycf1) show that they are congruent with the topology derived from 77 chloroplast protein-coding genes. Conclusions In this study, we provide detailed information on the 15 complete plastid genomes of Commelinoideae taxa. We identified characteristic pseudogenes and nucleotide diversity, which can be used to infer the family evolutionary history. Also, further research is needed to revise the position of Palisota in the current classification of Commelinaceae.


Insects ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 640
Author(s):  
Natalia R. Moyetta ◽  
Fabián O. Ramos ◽  
Jimena Leyria ◽  
Lilián E. Canavoso ◽  
Leonardo L. Fruttero

Hemocytes, the cells present in the hemolymph of insects and other invertebrates, perform several physiological functions, including innate immunity. The current classification of hemocyte types is based mostly on morphological features; however, divergences have emerged among specialists in triatomines, the insect vectors of Chagas’ disease (Hemiptera: Reduviidae). Here, we have combined technical approaches in order to characterize the hemocytes from fifth instar nymphs of the triatomine Dipetalogaster maxima. Moreover, in this work we describe, for the first time, the ultrastructural features of D. maxima hemocytes. Using phase contrast microscopy of fresh preparations, five hemocyte populations were identified and further characterized by immunofluorescence, flow cytometry and transmission electron microscopy. The plasmatocytes and the granulocytes were the most abundant cell types, although prohemocytes, adipohemocytes and oenocytes were also found. This work sheds light on a controversial aspect of triatomine cell biology and physiology setting the basis for future in-depth studies directed to address hemocyte classification using non-microscopy-based markers.


2007 ◽  
Vol 139 (3) ◽  
pp. 297-307 ◽  
Author(s):  
Željko Tomanović ◽  
Ehsan Rakhshani ◽  
Petr Starý ◽  
Nickolas G. Kavallieratos ◽  
Ljubiša Ž. Stanisavljević ◽  
...  

AbstractWe analyzed the phylogenetic relationships between eight Aphidius Nees and six Lysaphidus Smith species on the basis of 12 morphological characters by parsimony analysis. The consensus tree does not support the generic status of Lysaphidus. Aphidius iranicus, sp. nov., associated with Titanosiphon bellicosum Nevsky on Artemisia absinthium L. from Iran, is described. The new parasitoid species is described and illustrated by line drawings, and its diagnostic characters are discussed. The taxonomic position of the subgenus Tremblayia Tizado and Núñez-Pérez is also considered. Tremblayia and Lysaphidus are newly classified as synonyms of Aphidius. The following new or revised combinations are proposed: Aphidius adelocarinus Smith, comb. rev., A. ramythirus Smith, comb. rev., A. rosaphidis Smith, comb. rev., A. viaticus (Sedlag), comb. nov., A. arvensis (Starý), comb. nov., and A. erysimi (Starý), comb. nov.


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