Phylogenetic relationships and evolution in the genus Dissodactylus Smith, 1870 (Crustacea: Brachyura: Pinnotheridae)

1987 ◽  
Vol 65 (9) ◽  
pp. 2292-2310 ◽  
Author(s):  
Hugh Griffith

A cladogram indicating sister-group relationships within the pinnotherid crab genus Dissodactylus is constructed from analysis of 28 morphological characters. The outgroup method was used to determine character polarities. Parapinnixa and Sakaina are shown to be a monophyletic group, and are suggested to be the sister group of Dissodactylus. Within Dissodactylus, two mutually exclusive, monophyletic subgroups are found, one containing nine, the other four species. Both of these groups include Atlantic and Pacific representatives. Two Atlantic–Pacific species pairs are suggested to be sister species (D. mellitae–D. glasselli and D. primitivus–D. schmitti). Members of the group of nine species are inhabitants primarily of mellitid sand dollars, although one species, D. primitivus, is a symbiont of heart urchins (Spatangoida). Members of the group of four species are inhabitants of sea biscuits of the genus Clypeaster (Clypeasteridae). An evolutionary scenario is presented, which suggests that a free-living ancestor colonized mellitid sand dollars, and subsequent specializations led to the colonizations of the genus Clypeaster and genera of Spatangoida.

2012 ◽  
Vol 46 (6) ◽  
pp. 31-48
Author(s):  
K. B. Sukhomlin

Abstract Phylogenetic relationships among the Palaearctic genera of the subfamily Simuliinae are analyzed based on the matrix of 100 morphological characters and 37 taxa, including 6 outgroups. Parsimonic analysis was resulted in 3 consensus trees (weighting based on CI, RI and RC indices) of slightly different topology, which show monophyly of the subfamily Simuliinae, tribes Stegopternini, Nevermanniini, Wilhelmiini and Simuliini, and a possible sister-group relationships between the latter two tribes. Tribe Ectemniini is apparently a paraphyletic formation. The analysis also supports transferring of the Stegopternini and Nevermanniini from Prosimuliinae to Simuliinae.


2005 ◽  
Vol 26 (2) ◽  
pp. 139-147 ◽  
Author(s):  
Francisca do Val ◽  
Paulo Nuin

AbstractThe systematics and phylogenetic relationships of the family Leptodactylidae are controversial as is the intrafamilial phylogeny of the leptodactylids. Here we analyze the relationships of the leptodactylid subfamily Hylodinae. This subfamily has been considered to be monophyletic and composed of three genera, Hylodes, Crossodactylus and Megaelosia. In the present study 49 characters were used, based on different studies on Leptodactylidae phylogeny. Maximum parsimony methods with unweighted and successively weighted characters were used to estimate the phylogeny of the Hylodinae. Upon analysis, the data provided further evidence of the monophyletic status of the three genera, with Megaelosia being the basal genus and the other two genera being sister taxa. The analysis with successive weighting results in a more resolved topology of the species subgroups of the genus Hylodes and separates this genus from Crossodactylus and confirms that the hylodines are monophyletic.


1989 ◽  
Vol 63 (4) ◽  
pp. 454-483 ◽  
Author(s):  
Barry S. Kues

The benthic, free-living oyster Texigryphaea was the dominant constituent of many late Albian marine communities in the Texas and southern Western Interior regions. Large topotypic assemblages of three common lower–middle Washita Group species (T. navia and T. pitcheri in Oklahoma and T. tucumcarii in New Mexico) each display considerable morphological variation in valve shape and the proportions and expression of various features. Variation within an assemblage is partly due to ontogenetic changes but is mainly ecophenotypic, with local variation in nature of substrate, water turbulence, length of attachment time, and other factors influencing the final morphology of the mature shell. The T. navia assemblage is distinct in several important morphological characters from the other species, and the differences become more pronounced with growth. Texigryphaea navia appears to have been adapted to relatively firm substrates in moderately agitated conditions, in contrast to the other species, which occupied softer substrates in quieter environments. The essentially contemporaneous T. pitcheri and T. tucumcarii assemblages display much overlap in all measured dimensions of the left valve and in the range of intergrading morphs that compose each assemblage. Accordingly, T. tucumcarii is considered a synonym of T. pitcheri, representing populations of that species that lived in the West Texas-New Mexico area and developed only minor differences from the eastern populations. Within the T. navia topotypic assemblage are specimens intermediate between T. navia and T. pitcheri, and the eastern and western T. pitcheri assemblages contain forms apparently transitional to two other species, T. washitaensis and T. belviderensis. Ecophenotypic variation in the T. pitcheri assemblages appears to be greater than that in European Jurassic Gryphaea species and mirrors to some extent phyletic variation in European Jurassic Gryphaea lineages.


2018 ◽  
Vol 93 (2) ◽  
pp. 208-219
Author(s):  
J.F. Santos Neto ◽  
N.G.S. Costa ◽  
G.B. Soares ◽  
M.V. Domingues

AbstractTwo new species of Diaphorocleidus and one new species of Rhinoxenoides n. gen. are described from the gills of Acestrorhynchus falcatus (Bloch) from rivers of north-eastern Pará, Brazil. Diaphorocleidus jaymedeloyolai n. sp. is characterized by a male copulatory organ (MCO) possessing three counterclockwise coils; similar anchors with subtriangular superficial roots; a ventral bar with posteromedial projection; and hooks of pairs 1, 4 and 7 approximately three times longer than hook pair 5. Diaphorocleidus sclerocolpus n. sp. differs from its congeners by a dual-branched accessory piece articulated with the MCO and a sclerotized tubular vagina with a bottle-shaped vestibule. Rhinoxenoides n. gen. is proposed and is characterized by possessing: MCO sclerotized with clockwise coils; an accessory piece articulated to the base of MCO; a sinistroventral vaginal aperture; ventral anchor with conspicuous roots; dorsal anchor with superficial root five times longer than deep root; and absence of dorsal bar. The proposal of Rhinoxenoides n. gen. is also supported by its phylogenetic relationship with Protorhinoxenus prochilodi and species of Rhinoxenus, using 16 morphological characters, which resulted in the following hypothesis of sister-group relationships: Rhinoxenoides n. gen. [Protorhinoxenus (Rhinoxenus curimatae (R. nyttus (R. bulbovaginatus (R. guianensis, R. piranhus, R. euryxenus (R. arietinus, R. anaclaudiae)))))].


2011 ◽  
Vol 279 (1731) ◽  
pp. 1093-1099 ◽  
Author(s):  
Maria Heikkilä ◽  
Lauri Kaila ◽  
Marko Mutanen ◽  
Carlos Peña ◽  
Niklas Wahlberg

Although the taxonomy of the ca 18 000 species of butterflies and skippers is well known, the family-level relationships are still debated. Here, we present, to our knowledge, the most comprehensive phylogenetic analysis of the superfamilies Papilionoidea, Hesperioidea and Hedyloidea to date based on morphological and molecular data. We reconstructed their phylogenetic relationships using parsimony and Bayesian approaches. We estimated times and rates of diversification along lineages in order to reconstruct their evolutionary history. Our results suggest that the butterflies, as traditionally understood, are paraphyletic, with Papilionidae being the sister-group to Hesperioidea, Hedyloidea and all other butterflies. Hence, the families in the current three superfamilies should be placed in a single superfamily Papilionoidea. In addition, we find that Hedylidae is sister to Hesperiidae, and this novel relationship is supported by two morphological characters. The families diverged in the Early Cretaceous but diversified after the Cretaceous–Palaeogene event. The diversification of butterflies is characterized by a slow speciation rate in the lineage leading to Baronia brevicornis , a period of stasis by the skippers after divergence and a burst of diversification in the lineages leading to Nymphalidae, Riodinidae and Lycaenidae.


Author(s):  
Christopher J. Glasby ◽  
Patricia A. Hutchings ◽  
Kathryn Hall

A phylogenetic analysis of the polychaete clade Terebelliformia (Terebellida) was undertaken in order to test monophyly of families and subfamilies and to determine their affinities. Parsimony analyses of 41 terebelliform species with outgroup Owenia fusiformis and 46 morphological characters yielded 106–144 most parsimonious trees with length 250, consistency index=0·432, retention index=0·659 and rescaled consistency index=0·285. Monophyly was indicated for Alvinellidae, Ampharetidae, Terebellidae and Trichobranchidae and the terebellid subfamily Polycirrinae. Monophyly of Terebellidae is supported by the presence of a ridge-like tentacular membrane. Monophyly of Polycirrinae is supported by the loss of branchiae, trilobed upper lip, pinnate secondary notochaetae and ventro-lateral pads. Recognition of Polycirrinae renders taxa in the other terebellid subfamilies—Terebellinae and Thelepodinae—paraphyletic. Our results do not support previous classifications that placed Trichobranchidae as a subfamily of Terebellidae; rather it should be considered equal in rank with Alvinellidae, Ampharetidae, Terebellidae and Pectinariidae. The following relationships were obtained: (Trichobranchidae ((Alvinellidae, Ampharetidae) (Pectinariidae, Terebellidae))). This is the first time a Pectinariidae–Terebellidae sister group relationship has been found; it is supported by the synapomorphic presence of ventral glandular shields.


Zootaxa ◽  
2016 ◽  
Vol 4196 (2) ◽  
pp. 289
Author(s):  
SERGIO TICUL ÁLVAREZ-CASTAÑEDA ◽  
CONSUELO LORENZO

Since Sylvilagus bachmani (Lagomorpha: Leporidae) from the Baja California Peninsula and S. mansuetus from San Jose Island, Mexico, display an allopatric distribution and are closely related, their taxonomy is unclear. The phylogenetic relationships among specimens of both species were evaluated using two mitochondrial genes (Cyt b, COI) and the beta-fibrinogen nuclear gene intron 7 (β-fib I7). The genetic analyses revealed that S. mansuetus was included within the S. bachmani clade as the sister-group of S. b. cerrosensis. The genetic distances among S. b. cerrosensis and mansuetus were relatively low (1.3% with Cyt b), similar to intraspecific distances observed within other species of Sylvilagus. We consider mansuetus to be a subspecies of S. bachmani, and the morphological traits previously used to differentiate the two taxa should be used to distinguish S. b. mansuetus from the other subspecies of S. bachmani. 


1998 ◽  
Vol 11 (4) ◽  
pp. 267 ◽  
Author(s):  
J. P. Rourke

In Africa the Proteaceae are represented by 16 genera of which two (Dilobeia Thouars. and Malagasia L.Johnson and B.Briggs) are endemic to Madagascar and one (Faurea Harv.) is common to both Madagascar and Africa where it is widespread in forest and savannah woodland from the southern Cape to Eritrea. The remaining 13 genera are Cape-centred (10 are endemic to the western Cape) and with the exception of the monotypic riverine Brabejum L. (Grevilleoideae), are confined to fynbos (heathland) communities on oligotrophic soils. These 12 Cape heathland genera currently assigned to two subtribes (Proteinae and Aulacinae) within the subfamily Proteoideae have all been recently revised or are in the final stages of revision. Preliminary cladistic studies now suggest that they could be arranged in several new subtribes within the subfamily Proteoideae to reflect more accurately their phylogenetic relationships. Using morphological characters in a cladistic analysis, the South African Proteoideae (tribe Proteeae) resolve into two broad groups; Aulax Berg., Faurea Harv. and Protea L. form a weakly supported group while the second, large, well-supported group resolves into two clades in which the heterogeneous Leucadendron R.Br. stands apart while the other clade underpinned by Vexatorella Rourke resolves into two further groups, the ‘Leucospermum group’ and the ‘Serruria group’. The dioecious genera Leucadendron and Aulax previously united in the subtribe Aulacinae have been shown to differ markedly and should probably be placed in separate subtribes. Selection pressure, especially from fire and pollinators, has resulted in major morphological modifications in the 12 fynbos genera from the western Cape.


2007 ◽  
Vol 55 (3) ◽  
pp. 197 ◽  
Author(s):  
Paul M. Oliver ◽  
Mark N. Hutchinson ◽  
Steven J. B. Cooper

Diplodactylid geckos offer a model system for investigating the biogeographic history of Australia and adaptive radiations in the arid zone, but there is considerable uncertainty in the systematics of several key genera. We used sequence data from mitochondrial DNA to carry out a comprehensive analysis of phylogenetic relationships of geckos in the genus Diplodactylus. Parsimony and Bayesian analyses were highly concordant and allocated all species to one of two monophyletic clades, one comprising the species placed in the vittatus and conspicillatus species groups, the other comprising species placed in the stenodactylus and steindachneri species groups, plus D. byrnei, formerly in the vittatus group. The distinctness of these two clades is supported by external morphology of the digits, body and limb proportions, and osteology of the bones in the orbital region, and we use these characters to formally define the two clades as genera. We revive and expand the genus Lucasium for D. byrnei, D. steindachneri and the stenodactylus group, with the other species staying in a redefined Diplodactylus. The monotypic Rhynchoedura is distinct from Lucasium, although the Bayesian mtDNA analysis (but not parsimony) gives some support for a sister-group relationship between Lucasium and Rhynchoedura. Molecular data suggest that each of these clades represents a distinct radiation into semiarid and arid terrestrial habitats during the mid-Tertiary, well before the hypothesised Pliocene onset of major aridification.


2020 ◽  
Vol 96 (2) ◽  
pp. 455-498
Author(s):  
Kai Horst George

Uncovering the systematics of CopepodaHarpacticoida, the second-most abundant component of the meiobenthos after Nematoda, is of major importance for any further research dedicated especially to ecological and biogeographical approaches. Based on the evolution of the podogennontan first swimming leg, a new phylogenetic concept of the Ancorabolidae Sars and Cletodidae T. Scott sensu Por (Copepoda, Harpacticoida) is presented, using morphological characteristics. It confirms the polyphyletic status of the Ancorabolidae and its subfamily Ancorabolinae Sars and the paraphyletic status of the subfamily Laophontodinae Lang. Moreover, it clarifies the phylogenetic relationships of the so far assigned members of the family. An exhaustive phylogenetic analysis was undertaken using 150 morphological characters, resulting in the establishment of a now well-justified monophylum Ancorabolidae. In that context, the Ancorabolus-lineage sensu Conroy-Dalton and Huys is elevated to sub-family rank. Furthermore, the membership of Ancorabolina George in a rearranged monophylum Laophontodinae is confirmed. Conversely, the Ceratonotus-group sensu Conroy-Dalton is transferred from the hitherto Ancorabolinae to the Cletodidae. Within these, the Ceratonotus-group and its hypothesised sister-group Cletodes Brady are combined to form a monophyletic subfamily Cletodinae T. Scott, subfam. nov. Consequently, it was necessary to restructure the Ancorabolidae, Ancorabolinae and Laophontodinae and extend the Cletodidae to include the displacement and exclusion of certain taxa. Moreover, comparison of the Ancorabolidae, Cletodidae, Laophontoidea and other Podogennonta shows that the Ancorabolidae and Cletodidae form sister-groups in a monophylum Cletodoidea Bowman and Abele, which similarly has a sister-group-relationship with the Laophontoidea T. Scott. According to the present study, both taxa constitute a derived monophylum within the Podogennonta Lang.


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