Ammonites phylogenetic analysis: state of the art and new prospects

2004 ◽  
Vol 175 (5) ◽  
pp. 507-512 ◽  
Author(s):  
Isabelle Rouget ◽  
Pascal Neigeet ◽  
Jean-Louis Dommergues

Abstract Two main types of data are available to resolve phylogenies using fossils data: (1) stratigraphic ordering of taxa, and (2) morphological characters. In most phylogenetic studies dealing with ammonites, authors have given priority to the stratigraphic distribution of taxa. This practice is classically justified by the fact that the ammonite fossil record is frequently outstandingly good. In practice, the level of integration of stratigraphic and morphologic information in a single analysis depends on the confidence that authors have in the quality of data. Besides, many evolutionary concepts, which could differ over time and between authors (e.g. anagenesis, cladogenesis, iterative evolution), are added to these data to help infer phylogenetic relationships. As a result, phylogenetic hypotheses are based on eclectic methods which depend on the relative weight given to stratigraphic and morphologic information as well as on evolutionary concepts used. The validity of relationships proposed by previous authors is not dealt with in this paper. Instead, our goal is to draw attention to problems that these eclectic methods may cause, that is to say: (1) ammonites systematics is poorly formalised and (2) phylogenetic hypotheses as they are classically constructed are not rigorously testable. During the last 10 years, cladistic analysis has been applied to ammonites but is still unpopular among ammonitologists. However, studies have consistently shown that cladistics is not as unsuited a tool for ammonites phylogenetic reconstruction as is widely believed. Moreover, classical works open new questions about ammonite phylogeny and in particular, help to reappraise our view on the definition of morphological characters and their phylogenetic significance.

2006 ◽  
Vol 84 (2) ◽  
pp. 225-241 ◽  
Author(s):  
M Manuel

The most recent advances concerning the phylogeny and evolution of calcareous sponges (Calcarea or Calcispongia) are reviewed here, in the light of the history of taxonomy of the group and conceptions about its evolution, starting from Haeckel's works at the end of the 19th century. Calcisponge phylogeny has recently started to be addressed using modern tools of phylogenetic reconstruction: cladistic analysis of morphological characters and molecular phylogeny (so far using 18S and 28S rDNA sequences). The monophyly of calcareous sponges is strongly supported in these works, as is their subdivision into two clades, Calcinea (whose proposed synapomorphy is the basal position of nuclei in choanocytes, with no relation to the flagella) and Calcaronea (whose possible synapomorphy is the formation of the amphiblastula larva through the original process of eversion of the stomoblastula). While the molecular phylogeny of Calcinea is still in its infancy because of insufficient taxonomic sampling, several lines are emerging for the phylogeny of Calcaronea, and these are in strong disagreement with the classification issued from the "traditional" morphological approach. Phylogenetic hypotheses also permit the reconstruction of morphological character evolution, which appears complex and subject to a high level of homoplasy.


Zootaxa ◽  
2021 ◽  
Vol 5074 (1) ◽  
pp. 1-66
Author(s):  
ANDRZEJ WOLSKI

Cylapini, as currently circumscribed, is a relatively small group of plant bugs currently comprising 17 genera and 65 species. Most representatives of the tribe are distributed in the New World (10 genera and 47 species) with other members occurring in the Afrotropical, Oriental, and Australian regions. They have primarily tropical and subtropical distributions with only a few members inhabiting temperate regions. This paper provides a taxonomic review of three of the New World Cylapini genera: Cylapinus Carvalho, 1986, Cylapoides Carvalho, 1952, and Peltidocylapus Poppius, 1909. Most species are diagnosed and redescribed. Eight new species are described as new: Cylapinus yasunagai sp. nov., Peltidocylapus calyciformis sp. nov., P. caudatus sp. nov., P. ecuadorensis sp. nov., P. pallidus sp. nov., P. parallelus sp. nov., P. simplex sp. nov., and P. spinosus sp. nov. Cylapus festinabundus Bergroth, 1922 is transferred to Peltidocylapus (comb. nov.). Illustrations of male genitalia, scanning electron micrographs of selected structures of certain species, and an identification key of the genera Cylapinus, Cylapoides and Peltidocylapus are provided. Female genitalia are described and illustrated for the first time for most genera of Cylapini. A cladistic analysis of the tribe based on 81 morphological characters is presented as a contribution to the understanding of the ingroup relationships of Cylapini and its relationships with other groups of Cylapinae. The analysis comprises 30 ingroup species and 15 outgroup species. Both equal- and implied weighting parsimony analyses were used in the phylogenetic reconstruction. This analysis was based solely on morphological characters because an insufficient number of specimens suitable for molecular studies were available for most taxa. The study confirmed a close affinity of the taxa currently included in Cylapini, but the tribe was rendered paraphyletic by inclusion of the tribe Vanniini. The grouping comprising both Cylapini + Vanniini and most of its subordinated clades received low nodal support. Both analyses recovered a decisively supported clade comprising the New World genera Amapacylapus, Cylapus, Peltidocylapus, and Valdasus which accommodate most of the Cylapini species, justifying the recognition of the Cylapus complex suggested by previous authors. The results presented here are discussed and compared with previous phylogenetic hypotheses based on different datasets.  


1995 ◽  
Vol 43 (6) ◽  
pp. 557 ◽  
Author(s):  
MS Springer ◽  
LJ Hollar ◽  
JAW Kirsch

Andersen's 1912 monograph on megachiropterans remains the definitive work on the systematics of this group. Andersen argued that the Macroglossinae, containing the eonycterine and notopterine sections, are a monophyletic sister-group to other fruitbats (i.e. Andersen's Rousettus, Cynopterus and Epomophorus sections). Two recent molecular studies (DNA hybridisation and restriction mapping of ribosomal cistrons), as well as an analysis of female reproductive characters, challenge the monophyly of the Macroglossinae and several of Andersen's other conclusions such as the phylogenetic position of Nyctimene. We performed a cladistic analysis on 36 morphological characters, including 33 that were gleaned from Andersen, to determine whether phylogenetic hypotheses based on modem phylogenetic methods are in agreement with Andersen's original conclusions and to compare morphological and molecular phylogenetic hypotheses. Minimum-length trees based on parsimony are largely consistent with Andersen and support (1) a monophyletic Macroglossinae, within which the eonycterine section is paraphyletic with respect to a monophyletic notopterine section, (2) a monophyletic Cynopterus section, excepting the exclusion of Myonycteris, (3) a monophyletic Epomophorus section, excepting the exclusion of Plerotes, and (4) a paraphyletic Rousettus section, with several of the Rousettus-like forms branching off near the base of the tree. Bootstrapping analyses on a reduced data-set that included taxa shared in common with the DNA hybridisation study did not provide strong support (greater than or equal to 95%) for any clades but did provide moderate support (greater than or equal to 70) for several clades, including a monophyletic Macroglossinae. These findings are in marked contrast to the DNA hybridisation phylogeny. A high index of between-data-set incongruence is further evidence for the clash between DNA hybridisation and morphology. A phylogenetic framework was constructed on the basis of morphological data and DNA hybridisation data using a criterion of moderate support and shows little resolution, whereas employing a criterion of strong support produced a framework resolving several additional nodes. One implication of this framework is that characteristic macroglossine features such as a long tongue with a thick carpet of filiform papillae have evolved independently on several occasions (or evolved once and were lost several times). Rates of character evolution for the morphological characters employed in our analysis were calculated using divergence times estimated from DNA hybridisation data. Rates have apparently been fastest in the interior branches, and slower along the external branches, which suggests an early adaptive radiation in the history of fruitbats.


1995 ◽  
Vol 9 (6) ◽  
pp. 1211 ◽  
Author(s):  
MS Harlin ◽  
P Sundberg

A phylogeny for the 34 species we consider well enough described in the suborder Eureptantia (phylum Nemertea) is inferred by cladistic analysis based on 38 morphological characters. The phylogenetic reconstruction indicates that many previously recognised genera and families are paraphyletic. These findings are discussed and compared with earlier classifications. We also present an identification key to the species based on the cladistic analysis.


2007 ◽  
Vol 21 (4) ◽  
pp. 311 ◽  
Author(s):  
Christopher Mah

Morphology-based phylogenetic hypotheses developed for living and fossil goniasterid asteroids have provided several unique opportunities to study bathymetric and biogeographic shifts for an ecologically important group of prominent, megafaunal invertebrates. A cladistic analysis of 18 ingroup taxa employing 65 morphological characters resulted in a single most parsimonious tree. The tree supports assignment of the Atlantic Tosia parva (Perrier, 1881) and the Pacific Tosia queenslandensis Livingstone, 1932 to new, separate genera. The phylogenetic tree supports offshore to onshore bathymetric shifts between basal and derived taxa. The phylogeny is also consistent with historical events surrounding the separation of Antarctica from Australia and South Africa. Buterminaster Blake & Zinsmeister, 1988 from the Eocene La Meseta Formation, Antarctic Peninsula, was included in the phylogenetic analysis and is now supported as the only fossil species in the genus Pentagonaster Gray, 1840. Pentagonaster stibarus H. L. Clark, 1914 is separated from synonymy with P. dubeni Gray, 1847 and resurrected as a valid species. The new genus, Akelbaster, gen. nov., shows unusual new structures that resemble cribiform organs, although their function has not been determined. One specific ingroup lineage, including Tosia and Pentagonaster, attains a much larger adult size than those of its sister-taxa, suggesting that Cope’s rule may apply to asteroids within this clade. Pentagonaster and related genera are revised. Descriptions of four new genera and three new species are presented, including: Akelbaster novaecaledoniae, gen. nov., sp. nov., Ryukuaster onnae, gen. nov., sp. nov., Eknomiaster beccae, sp. nov., Pawsonaster parvus, gen. nov., comb. nov. and Anchitosia queenslandensis, gen. nov., comb. nov.


Zootaxa ◽  
2011 ◽  
Vol 2861 (1) ◽  
pp. 1 ◽  
Author(s):  
MARÍA ANA TOVAR-HERNÁNDEZ ◽  
LUIS F. CARRERA-PARRA

The present study deals with the revision of type and non-type material from 14 species of Megalomma Johansson, 1925 (Polychaeta: Sabellidae) which have been described from America: M. bioculatum (Ehlers, 1887), M. carunculata Tovar-Hernández and Salazar-Vallejo, 2008, M. circumspectum (Moore, 1923), M. coloratum (Chamberlin, 1919), M. fauchaldi Giangrande, Licciano and Gambi, 2007, M. gesae Knight-Jones, 1997, M. heterops Perkins, 1984, M. lobiferum (Ehlers, 1887), M. modestum (de Quatrefages, 1866), M. pacifici (Grube, 1859), M. perkinsi Tovar-Hernández and Salazar-Vallejo, 2006, M. pigmentum Reish, 1963, M. roulei (Gravier, 1908b) and M. splendidum (Moore, 1905); five from other world-wide localities: M. acrophthalmos (Grube, 1878), M. claparedei (Gravier, 1908a), M. lanigera (Grube, 1846), M. mushaense (Gravier, 1908a), M. sp.; and the formal description of a new species: Megalomma georgiense n. sp., from USA. The genus Megalomma was amended based on radiolar, peristomial and chaetal features. Megalomma roulei (Gravier, 1908b) is declared incertae sedis. Megalomma clara (Chamberlin, 1919) is synonymized with M. coloratum (Chamberlin, 1919). Megalomma pigmentum Reish, 1963 and M. monoculata Hartmann-Schröder, 1965 are cryptic. A key is included to the American species of Megalomma. A cladistic analysis was conducted based on examination of type material from the species reviewed in this study and from twelve species based on original descriptions (M. cinctum Fitzhugh, 2003, M. inflata Capa & Murray, 2009, M. interrupta Capa and Murray, 2009, M. kaikourense Knight-Jones, 1997, M. messapicum Giangrande and Licciano, 2008, M. miyukiae Nishi, 1998, M. multioculatum Fitzhugh, 2002, M. nechamae Knight-Jones, 1997, M. phyllisae Capa and Murray, 2009, M. trioculatum Reish, 1968, M. quadrioculatum (Willey, 1905) and M. vesiculosum (Montagu, 1815)). The phylogenetic reconstruction of Megalomma using parsimony analysis of 32 morphological characters yielded 26 equally most parsimonious trees (CI= 0.38, RI= 0.56). The hypotheses by Capa and Murray (2009) that considered species with dorsal collar margins fused to the faecal groove (Knight-Jones’s group 1) as part of an apomorphic clade, and those with dorsal collar margins unfused to the faecal groove (Knight-Jones’s group 2) as plesiomorphic, are not supported in this present study. In our analysis, species nested in group 2 comprises one of the most derived clades, while the clade containing species of group 1 was not recovered. DNA barcoding of M. coloratum, M. lobiferum and M. carunculata is included.


1994 ◽  
Vol 72 (1) ◽  
pp. 122-134 ◽  
Author(s):  
Marlise Franke ◽  
Joseph Morton

The taxonomic significance of morphological characters in fungi of Glomales (Zygomycetes) has been based solely on superficial resemblance. Ontogenetic comparisons among isolates of Scutellospora pellucida and Scutellospora heterogama were used to resolve discrete stages of differentiation in which characters were delimited and ordered hierarchically according to temporal and spatial origin in development. Character concepts were revised, and both species were redescribed. A spore wall, two inner walls, and a germination shield were designated primary characters because they appeared separately and in linear succession. Secondary characters included distinct layers differentiated within each wall. Tertiary characters were qualitative and quantitative properties of each layer. All characters in each developmental stage did not vary in two hosts, in separate experiments, and among five isolates of each species. Stability was attributed to causal epigenetic linkages between stages of differentiation, wherein each new stage depended on differentiation of all characters in the preceding stage. Characters at successively lower hierarchical levels are predicted to specify progressively less inclusive taxa in cladistic analysis. Developmental patterns will improve reinterpretations of phylogenetic relationships and provide a more empirical basis for grouping and ranking of organisms into species and higher taxa at the morphological level. Key words: evolution, morphology, mycorrhizae, taxonomy, VAM fungi.


Author(s):  
D. G. Melnikov ◽  
L. I. Krupkina

Based on the published data of molecular phylogenetic studies of the tribe Cariceae Dumort. genera (Cyperaceae), obtained by an international collaboration (The Global Carex Group, 2016; et al.), and morphological characters of the genera (Kukkonen, 1990; and others), new nomenclatural combinations and replacement names in the genus Carex L. are published for 11 species, one subspecies and two sections previously included in the genus Kobresia Willd.


Insects ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 518
Author(s):  
Bronwyn Egan ◽  
Zwannda Nethavhani ◽  
Barbara van Asch

Macrotermes termites play important ecological roles and are consumed by many communities as a delicacy and dietary complement throughout Africa. However, lack of reliable morphological characters has hampered studies of Macrotermes diversity in a wide range of scientific fields including ecology, phylogenetics and food science. In order to place our preliminary assessment of the diversity of Macrotermes in South Africa in context, we analysed a comprehensive dataset of COI sequences for African species including new and publicly available data. Phylogenetic reconstruction and estimates of genetic divergence showed a high level of incongruity between species names and genetic groups, as well as several instances of cryptic diversity. We identified three main clades and 17 genetic groups in the dataset. We propose that this structure be used as a background for future surveys of Macrotermes diversity in Africa, thus mitigating the negative impact of the present taxonomic uncertainties in the genus. The new specimens collected in Limpopo fell into four distinct genetic groups, suggesting that the region harbours remarkable Macrotermes diversity relative to other African regions surveyed in previous studies. This work shows that African Macrotermes have been understudied across the continent, and that the genus contains cryptic diversity undetectable by classic taxonomy. Furthermore, these results may inform future taxonomic revisions in Macrotermes, thus contributing to advances in termitology.


Zootaxa ◽  
2012 ◽  
Vol 3238 (1) ◽  
pp. 39 ◽  
Author(s):  
FELIPE LORENZ SIMÕES ◽  
AUGUSTO FERRARI ◽  
JOCÉLIA GRAZIA

The genus Elsiella Froeschner, 1981 is validated based on the analysis of a recently found male specimen of E. plana(Walker, 1867). A cladistic analysis comprising a data set of 40 morphological characters and 22 taxa, including the generaElsiella, Serdia Stål, Similliserdia Fortes & Grazia, Neotibilis Grazia & Barcellos, and Tibilis Stål, was performed. Elsiellaplana is redescribed and illustrated. Maps are provided for Elsiella and Serdia with biogeographical considerations for Serdia.


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