Further polyphyly of pinnotheroid crabs: the molecular phylogenetic position of the polychaete-associated Aphanodactylidae

2018 ◽  
Vol 32 (1) ◽  
pp. 92 ◽  
Author(s):  
Ling Ming Tsang ◽  
Shane T. Ahyong ◽  
Hsi-Te Shih ◽  
Peter K. L. Ng

Pea crabs of the superfamily Pinnotheroidea De Haan, 1833 are known for their obligate commensal relationships with other marine invertebrates. The concomitant specialisations and adaptations of pinnotheroids have resulted in superficially similar body forms that include a high degree of structural reduction. This has confounded interpretation of their phylogenetic position in the Brachyura and interrelationships within Pinnotheroidea, though all were nevertheless believed to be united by a monophyletic origin of obligate commensalism. The family Aphanodactylidae Ahyong & Ng, 2009 was proposed for a group of genera associated with tube-dwelling polychaetes formerly classified in Pinnotheridae, and provisionally retained in the Pinnotheroidea. We investigated the phylogenetic position of Aphanodactylidae using molecular data from three markers (mitochondrial 12S and 16S rRNAs, and nuclear histone H3) covering five of the 12 described aphanodactylid species and a total of 15 thoracotreme families. We found Aphanodactylidae to be monophyletic, but widely distant from Pinnotheridae and instead most closely related to Macrophthalmidae (Ocypodoidea) and Varunidae (Grapsoidea). Therefore, the family Aphanodactylidae is corroborated, but its placement in Pinnotheroidea is rejected. Instead, the phylogenetic position of Aphanodactylidae, as clearly distant from other pinnotheroids, demonstrates that obligate commensalism has evolved independently multiple times within Thoracotremata.

Biologia ◽  
2011 ◽  
Vol 66 (4) ◽  
Author(s):  
Christina Bock ◽  
Marie Pažoutová ◽  
Lothar Krienitz

AbstractFollowing traditional morphological concepts, the genus Coronastrum is considered to be a rare member of the Scenedesmaceae (Chorophyceae). This classification may be called into question when molecular data are taken into account as well. Recent molecular phylogenetic studies revealed the polyphyletic origin of the family Scenedesmaceae within the Chlorophyceae and Trebouxiophyceae. In a combined approach of morphological analyses, SSU/ITS rRNA gene phylogeny and comparison of the ITS secondary structure, we analysed the systematics of Coronastrum strains available in public strain collections. Our molecular analyses revealed a new subclade within the Chlorella clade of the Chlorellaceae consisting of Coronastrum ellipsoideum, two strains with Dictyosphaerium-like morphology and one strain which fits the description of the genus Parachlorella. Four additional strains formed together a new lineage within the genus Parachlorella in the Parachlorella clade of the Chlorellaceae. These strains differ from the already known Parachlorella species in complementary base changes within the ITS2 and are here described for the first time as Parachlorella hussii sp. nov.


2019 ◽  
Vol 94 ◽  
Author(s):  
S.V. Shchenkov ◽  
S.A. Denisova ◽  
G.A. Kremnev ◽  
A.A. Dobrovolskij

Abstract The phylogenetic position of most xiphidiocercariae from subgroups Cercariae virgulae and Cercariae microcotylae remains unknown or unclear, even at the family level. In this paper, we studied the morphology and molecular phylogeny of 15 microcotylous and virgulate cercariae (11 new and four previously described ones). Based on morphological and molecular data, we suggested five distinct morphological types of xiphidiocercariae, which are a practical alternative to Cercariae virgulae and Cercariae microcotylae subgroups. Four of these types correspond to actual digenean taxa (Microphallidae, Lecithodendriidae, Pleurogenidae and Prosthogonimidae), while the fifth is represented by Cercaria nigrospora Wergun, 1957, which we classified on the basis of molecular data for the first time. We reassessed the relative importance of morphological characters used for the classification of virgulate and microcotylous cercariae, and discussed the main evolutionary trends within xiphidiocercariae. Now stylet cercariae can be reliably placed into several sub-taxa of Microphalloidea on the basis of their morphological features.


2014 ◽  
Vol 83 (3) ◽  
pp. 195-S7 ◽  
Author(s):  
Roberto Arrigoni ◽  
Zoe T. Richards ◽  
Chaolun Allen Chen ◽  
Andrew H. Baird ◽  
Francesca Benzoni

Novel micromorphological characters in combination with molecular studies have led to an extensive revision of the taxonomy and systematics of scleractinian corals. In the present work, we investigate the macro- and micromorphology and the phylogenetic position of the genera Australomussa and Parascolymia, two monotypic genera ascribed to the family Lobophylliidae. The molecular phylogeny of both genera was addressed using three markers, the partial mitochondrial COI gene and the nuclear histone H3 and the ribosomal ITS region. Based on molecular data, Australomussa and Parascolymia belong to the Lobophylliidae and they cluster together with the genera Lobophyllia and Symphyllia within the same clade. While A. rowleyensis and P. vitiensis are closely related based on the three gene regions examined, their macro and micromorphology suggest that these species are distinct, differing in several characters, such as continuity and thickness of the costosepta, the number of septa, septal tooth height, spacing, and shape, and the distribution and shape of granules. Thus, we revise the taxonomic status of the genus Australomussa as a junior synonym of Parascolymia.


2021 ◽  
Vol 106 ◽  
pp. 325-339
Author(s):  
Shirley A. Graham ◽  
Peter W. Inglis ◽  
Taciana B. Cavalcanti

Crenea Aubl. (Lythraceae) is a ditypic genus of subshrubs occurring in mangrove vegetation on the coasts of northern South America. Phylogenetic analyses based on morphology have offered unresolved and conflicting phylogenetic positions for the genus in the family. This study presents the first molecular sequences for Crenea, from nrITS, rbcL, trnL, trnL-F, and matK regions. Molecular phylogenetic analyses find full support for Crenea within Ammannia L., a relationship not previously recognized. Ammannia is a globally distributed genus of terrestrial to amphibious herbs mostly occurring in freshwater marshes and wetlands. It was recently reconfigured based on phylogenetic evidence to include the genera Nesaea Comm. ex Kunth and Hionanthera A. Fern. & Diniz. The transfer of Crenea to Ammannia further extends the morphological, ecological, and biogeographical diversity of Ammannia and provides the final evidence defining Ammannia as a monophyletic lineage of the Lythraceae. A revised circumscription of Ammannia s.l. adds several new morphological character states and the first species in the genus restricted to mangrove vegetation. Two changes in taxonomic status are made: Ammannia maritima (Aubl.) S. A. Graham, P. W. Inglis, & T. B. Cavalc., comb. nov., and Ammannia patentinervius (Koehne) S. A. Graham, P. W. Inglis, & T. B. Cavalc., comb. nov. The new combinations are described, a list of exsiccatae examined is provided, and the effects of the reconfiguration to the morphology and biogeography of the genus are detailed.


2012 ◽  
Vol 81 (3) ◽  
pp. 125-146 ◽  
Author(s):  
Francesca Benzoni ◽  
Roberto Arrigoni ◽  
Fabrizio Stefani ◽  
Bastian T. Reijnen ◽  
Simone Montano ◽  
...  

The scleractinian species Psammocora explanulata and Coscinaraea wellsi were originally classified in the family Siderastreidae, but in a recent morpho-molecular study it appeared that they are more closely related to each other and to the Fungiidae than to any siderastreid taxon. A subsequent morpho-molecular study of the Fungiidae provided new insights regarding the phylogenetic relationships within that family. In the present study existing molecular data sets of both families were analyzed jointly with those of new specimens and sequences of P. explanulata and C. wellsi. The results indicate that both species actually belong to the Cycloseris clade within the family Fungiidae. A reappraisal of their morphologic characters based on museum specimens and recently collected material substantiate the molecular results. Consequently, they are renamed Cycloseris explanulata and C. wellsi. They are polystomatous and encrusting like C. mokai, another species recently added to the genus, whereas all Cycloseris species were initially thought to be monostomatous and free-living. In the light of the new findings, the taxonomy and distribution data of C. explanulata and C. wellsi have been updated and revised. Finally, the ecological implications of the evolutionary history of the three encrusting polystomatous Cycloseris species and their free-living monostomatous congeners are discussed.


2020 ◽  
Vol 86 (4) ◽  
pp. 401-421 ◽  
Author(s):  
Giulia Fassio ◽  
Valeria Russini ◽  
Barbara Buge ◽  
Stefano Schiaparelli ◽  
Maria Vittoria Modica ◽  
...  

ABSTRACT Species in the family Capulidae (Littorinimorpha: Capuloidea) display a wide range of shell morphologies. Several species are known to live in association with other benthic invertebrates—mostly bivalves and sabellid worms, but also other gastropods—and are believed to be kleptoparasitic filter feeders that take advantage of the water current produced by the host. This peculiar trophic ecology, implying a sedentary lifestyle, has resulted in highly convergent shell forms. This is particularly true for the genus Hyalorisia Dall, 1889, which occurs in deep water in the Caribbean and Indo-West Pacific provinces, with two nominal species recognized so far. Combining morphological, ecological and molecular data, we assessed the diversity of the genus, its phylogenetic position inside the family and its association with its bivalve host, the genus Propeamussium de Gregorio, 1884 (Pectinoidea), resulting in the description of nine new cryptic species. When sympatric, species of Hyalorisia are associated with different host species, but the same species of Propeamussium may be the host of several allopatric species of Hyalorisia.


Phytotaxa ◽  
2017 ◽  
Vol 319 (1) ◽  
pp. 84 ◽  
Author(s):  
XUDONG LIU ◽  
HUAN ZHU ◽  
BENWEN LIU ◽  
GUOXIANG LIU ◽  
ZHENGYU HU

The genus Nephrocytium Nägeli is a common member of phytoplankton communities that has a distinctive morphology. Its taxonomic position is traditionally considered to be within the family Oocystaceae (Trebouxiophyceae). However, research on its ultrastructure is rare, and the phylogenetic position has not yet been determined. In this study, two strains of Nephrocytium, N. agardhianum Nägeli and N. limneticum (G.M.Smith) G.M.Smith, were identified and successfully cultured in the laboratory. Morphological inspection by light and electron microscopy and molecular phylogenetic analyses were performed to explore the taxonomic position. Ultrastructure implied a likely irregular network of dense and fine ribs on the surface of the daughter cell wall that resembled that of the genus Chromochloris Kol & Chodat (Chromochloridaceae). Phylogenetic analyses revealed that Nephrocytium formed an independent lineage in the order Sphaeropleales (Chlorophyceae) with high support values and a close phylogenetic relationship with Chromochloris. Based on combined morphological, ultrastructural and phylogenetic data, we propose a re-classification of Nephrocytium into Sphaeropleales, sharing a close relationship with Chromochloris.


2012 ◽  
Vol 81 (1) ◽  
pp. 43-54 ◽  
Author(s):  
James D. Reimer ◽  
Meifang Lin ◽  
Takuma Fujii ◽  
David J.W. Lane ◽  
Bert W. Hoeksema

The zoanthid genus Sphenopus (Cnidaria: Anthozoa: Zoantharia), like many other brachycnemic zoanthids, is found in shallow subtropical and tropical waters, but is uniquely unitary (solitary, monostomatous), azooxanthellate, and free-living. With sparse knowledge of its phylogenetic position, this study examines the phylogenetic position of Sphenopus within the family Sphenopidae utilizing specimens from southern Taiwan and Brunei collected in 1999-2011, and furthermore analyzes the evolution of its unique character set via ancestral state reconstruction analyses. Phylogenetic analyses surprisingly show Sphenopus to be phylogenetically positioned within the genus Palythoa, which is colonial (polystomatous), zooxanthellate, and attached to solid substrate. Ancestral state reconstruction strongly indicates that the unique characters of Sphenopus have evolved recently within Palythoa and only in the Sphenopuslineage. These results indicate that zoanthid body plans can evolve with rapidity, as in some other marine invertebrates, and that the traditional definitions of zoanthid genera may need reexamination.


Zootaxa ◽  
2005 ◽  
Vol 891 (1) ◽  
pp. 1 ◽  
Author(s):  
Magdalena Szarowska ◽  
Andrzej Falniowski ◽  
FRANK Riedel ◽  
Thomas Wilke

The phylogenetic position of the subfamily Pyrgulinae within the superfamily Rissooidea has been discussed very controversially. Different data sets not only led to different evolutionary scenarios but also to different systematic classifications of the taxon. The present study uses detailed anatomical data for two pyrgulinid taxa, the type species of the subfamily, Pyrgula annulata (Linnaeus, 1767), and the type species of the little known genus Dianella, D. thiesseana (Kobelt, 1878), as well as DNA sequencing data of three gene fragments from representatives of eight rissooidean families to A) infer the phylogenetic position of Pyrgulinae with emphasis on its relationships within the family Hydrobiidae, B) to study the degree of concordance between anatomyand DNAbased phylogenies and C) to trace the evolution of anatomical characters along a multi-gene molecular phylogeny to find the anatomical characters that might be informative for future cladistic analyses. Both anatomical and molecular data sets indicate either a very close or even sister-group relationship of Pyrgulinae and Hydrobiinae. However, there are major conflicts between the two data sets on and above the family level. Notably, Hydrobiidae is not monophyletic in the anatomical analysis. The reconstruction of anatomical character evolution indicates that many of the characters on which the European hydrobioid taxonomy is primarily based upon are problematic. The inability to clearly separate some hydrobiids from other distinct families based on those characters might explain why until only a few years ago, "Hydrobiidae" was a collecting box for numerous rissooidean taxa (mostly species with shells small and lacking any characteristic features). The present study not only stresses the need for comprehensive molecular studies of rissooidean taxa, it also demonstrates that much of the problems surrounding anatomical analyses in rissooidean taxa are due to the lack of comprehensive data for many representatives. In order to aid future comparativeanatomical studies and a better understanding of character evolution in the species-rich family Hydrobiidae, detailed anatomical descriptions for P. annulata and D. thiesseana are provided.Key words: Pyrgulinae, Pyrgula, Dianella, Hydrobiidae, phylogeny, DNA, anatomy, Greece


Zootaxa ◽  
2003 ◽  
Vol 355 (1) ◽  
pp. 1 ◽  
Author(s):  
WILLIAM P. LEONARD ◽  
LYLE CHICHESTER ◽  
JIM BAUGH ◽  
THOMAS WILKE

A new genus and species of arionid slug, Kootenaia burkei n. gen. et n. sp., are formally described from northern Idaho, United States. This taxonomic decision is based on comparative anatomical and molecular data involving representatives of a total of ten species and three additional genera (Hemphillia, Prophysaon, and Zacoleus) of the family Arionidae. The anatomical analyses show that the new genus is characterized by a major autapomorphy, the complete absence of an epiphallus, which is found in all other arionids. The molecular analyses using two mitochondrial genes and the anatomical data produce congruent topologies. Overall, there is a high degree of concordance between the anatomical and molecular datasets.


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