scholarly journals The accessory neural arch: development, morphology, and systematic distribution

Zoomorphology ◽  
2021 ◽  
Author(s):  
Philipp Thieme ◽  
Timo Moritz

AbstractThe accessory neural arch is an oddly distributed character present in several non-acanthomorph teleostean taxa. Its homology was often implied but never satisfyingly tested. In this study, we attended this pending problem. We analyzed the morphology, development, and systematic distribution of the accessory neural arch in teleosts. Using a comprehensive taxon sampling of cleared and stained specimens, we evaluated if the accessory neural arch fulfils existing homology criteria. We then combined these data with recent genetic phylogenies and ancestral character state estimation to reconstruct the evolutionary history of the accessory neural arch. While its gross morphology and development fit homology criteria, results from ancestral character state estimations suggest multiple independent evolutions within teleosts. Although the accessory neural arch cannot be homologous between several teleostean taxa, the concept of parallelism may explain the presence of such a similar character in a variety of non-acanthomorph teleostean taxa.

Author(s):  
Agustín J Elias-Costa ◽  
Julián Faivovich

Abstract Cascades and fast-flowing streams impose severe restrictions on acoustic communication, with loud broadband background noise hampering signal detection and recognition. In this context, diverse behavioural features, such as ultrasound production and visual displays, have arisen in the evolutionary history of torrent-dwelling amphibians. The importance of the vocal sac in multimodal communication is being increasingly recognized, and recently a new vocal sac visual display has been discovered: unilateral inflation of paired vocal sacs. In the diurnal stream-breeding Hylodidae from the Atlantic forest, where it was first described, this behaviour is likely to be enabled by a unique anatomical configuration of the vocal sacs. To assess whether other taxa share this exceptional structure, we surveyed torrent-dwelling species with paired vocal sacs across the anuran tree of life and examined the vocal sac anatomy of exemplar species across 18 families. We found striking anatomical convergence among hylodids and species of the distantly related basal ranid genera Staurois, Huia, Meristogenys and Amolops. Ancestral character state reconstruction identified three new synapomorphies for Ranidae. Furthermore, we surveyed the vocal sac configuration of other anuran species that perform visual displays and report observations on what appears to be unilateral inflation of paired vocal sacs, in Staurois guttatus – an extremely rare behaviour in anurans.


Author(s):  
Sergei Tarasov ◽  
Istvan Miko ◽  
Matthew Yoder ◽  
Josef Uyeda

Ancestral character state reconstruction has been long used to gain insight into the evolution of individual traits in organisms. However, organismal anatomies (= entire phenotypes) are not merely ensembles of individual traits, rather they are complex systems where traits interact with each other due to anatomical dependencies (when one trait depends on the presence of another trait) and developmental constraints. Comparative phylogenetics has been largely lacking a method for reconstructing the evolution of entire organismal anatomies or organismal body regions. Herein, we present a new approach named PARAMO (Phylogenetic Ancestral Reconstruction of Anatomy by Mapping Ontologies, Tarasov and Uyeda 2019) that takes into account anatomical dependencies and uses stochastic maps (i.e., phylogenetic trees with an instance of mapped evolutionary history of characters, Huelsenbeck et al. 2003) along with anatomy ontologies to reconstruct organismal anatomies. Our approach treats the entire phenotype or its component body regions as single complex characters and allows exploring and comparing phenotypic evolution at different levels of anatomical hierarchy. These complex characters are constructed by ontology-informed amalgamation of elementary characters (i.e., those coded in character matrix) using stochastic maps. In our approach, characters are linked with the terms from an anatomy ontology, which allows viewing them not just as an ensemble of character state tokens but as entities that have their own biological meaning provided by the ontology. This ontology-informed framework provides new opportunities for tracking phenotypic radiations and anatomical evolution of organisms, which we explore using a large dataset for the insect order Hymenoptera (sawflies, wasps, ants and bees).


2021 ◽  
Author(s):  
Damián Villaseñor-Amador ◽  
José Alberto Cruz ◽  
Nut Xanat Suárez

Representative locomotion types in lizards include terrestrial, arboreal, grass swimmer, sand swimmer and bipedal. Few studies explain the locomotion habit of extinct lizards, and even less asses those of bipedal ones. Here, we use quantitative methods to infer the type of locomotion of two Albian Mexican lizards (Lower Cretaceous) and three Cretaceous lizards from Brazil, North America and Spain, assessing the similarities of the hindlimb-forelimb length ratio amongst extinct and extant species. Additionally, an ancestral character state reconstruction analysis was performed, to evaluate the evolution of lizard locomotion habits. The species Huehuecuetzpalli mixtecus was bipedal while Tijubina pontei was facultative bipedal, Hoyalacerta sanzi, Tepexisaurus tepexii and Polyglyphanodon sternbergi cannot be differentiated amongst terrestrial or arboreal with the approach used in this work. The ancestral character state reconstruction analysis showed a terrestrial ancestral locomotion type, with a basal character state of hindlimbs longer than forelimbs. Equal length between hind and forelimbs appear to be a derivate state that evolved multiple times in lizard evolutionary history.


2019 ◽  
Vol 104 (1) ◽  
pp. 69-82 ◽  
Author(s):  
Mónica M. Carlsen ◽  
Thomas B. Croat

This study presents an evaluation of the currently accepted sectional classification of the genus Anthurium Schott (Araceae) in light of a recently published molecular phylogeny for the group. In general, disagreements between these two occur because many diagnostic morphological characters used in the sectional classification turned out to be highly homoplasious within Anthurium, with multiple independent gains or losses of seemingly similar morphologies in distantly related clades. A new sectional classification of Anthurium that more accurately represents species relationships and the evolutionary history of the genus is much needed, and here we propose the first steps toward it. Results from this study suggest that out of the 18 sections and two series recognized in Anthurium, only seven of these groups are monophyletic (i.e., sections Andiphilum (Schott) Croat, Calomystrium (Schott) Engl., Dactylophyllium (Schott) Engl., Leptanthurium (Schott) Engl., Polyphyllium Engl., Tetraspermium (Schott) Engl., and the newly recognized section Multinervia (Croat) Carlsen & Croat, previously a series within section Pachyneurium (Schott) Engl.). All other sections are either not monophyletic or their monophyly could not be accurately tested. A complete revision of the sectional classification of Anthurium will require a more comprehensive taxon sampling and a better supported molecular phylogeny.


Author(s):  
Robert J Kallal ◽  
Dimitar Dimitrov ◽  
Miquel A Arnedo ◽  
Gonzalo Giribet ◽  
Gustavo Hormiga

Abstract We address some of the taxonomic and classification changes proposed by Kuntner et al. (2019) in a comparative study on the evolution of sexual size dimorphism in nephiline spiders. Their proposal to recircumscribe araneids and to rank the subfamily Nephilinae as a family is fundamentally flawed as it renders the family Araneidae paraphyletic. We discuss the importance of monophyly, outgroup selection, and taxon sampling, the subjectivity of ranks, and the implications of the age of origin criterion to assign categorical ranks in biological classifications. We explore the outcome of applying the approach of Kuntner et al. (2019) to the classification of spiders with emphasis on the ecribellate orb-weavers (Araneoidea) using a recently published dated phylogeny. We discuss the implications of including the putative sister group of Nephilinae (the sexually dimorphic genus Paraplectanoides) and the putative sister group of Araneidae (the miniature, monomorphic family Theridiosomatidae). We propose continuation of the phylogenetic classification put forth by Dimitrov et al. (2017), and we formally rank Nephilinae and Phonognathinae as subfamilies of Araneidae. Our classification better reflects the understanding of the phylogenetic placement and evolutionary history of nephilines and phonognathines while maintaining the diagnosability of Nephilinae. It also fulfills the fundamental requirement that taxa must be monophyletic, and thus avoids the paraphyly of Araneidae implied by Kuntner et al. (2019).


2016 ◽  
Vol 3 (10) ◽  
pp. 160453 ◽  
Author(s):  
Sandra R. Schachat ◽  
George W. Gibbs

Details of the ancestral groundplan of wing venation in moths remain uncertain, despite approximately a century of study. Here, we describe a 3-branched subcostal vein, a 5-branched medial vein and a 2-branched cubitus posterior vein on the forewing of Agathiphaga vitiensis Dumbleton 1952 from Vanuatu. Such veins had not previously been described in any Lepidoptera. Because wing veins are typically lost during lepidopteran evolutionary history, rarely—if ever—to be regained, the venation of A. vitiensis probably represents the ancestral character state for moths. Wing venation is often used to identify fossil insects as moths, because wing scales are not always preserved; the presence of a supposedly trichopteran 3-branched subcostal vein in crown Lepidoptera may decrease the certainty with which certain amphiesmenopteran fossils from the Mesozoic can be classified. And because plesiomorphic veins can influence the development of lepidopteran wing patterns even if not expressed in the adult wing, the veins described here may determine the location of wing pattern elements in many lepidopteran taxa.


1995 ◽  
Vol 73 (6) ◽  
pp. 1048-1064 ◽  
Author(s):  
Mark E. Siddall ◽  
Eugene M. Burreson

The phylogenetic relationships of leeches were investigated by examining 22 species representative of the 10 euhirudinean familes in a cladistic analysis. Forty-five characters relating to internal and external morphology as well as cocoon deposition characteristics were used. Polarization of character states was accomplished using Acanthobdella peledina as the sister-taxon to the Euhirudinea. Two equally parsimonious solutions resulted. One was chosen as a preferred tree on the basis of defensible character state transformations. Previous speculations as to evolutionary branching patterns are largely consistent with the results obtained by cladistic analysis. Similarly, contemporary taxonomic groupings of leeches into higher taxonomic categories were found to be largely consistent with monophyletic groups identified in the analysis. The family Piscicolidae was found to be paraphyletic; elevating the constituent piscicolid subfamilies to the level of family is proposed. The origin of sanguivory as a life-history mode was investigated by optimizing this characteristic on the phylogenetic hypothesis, indicating the possibility of at least two origins of blood-feeding in the evolutionary history of leeches, depending largely on how the feeding biology of acanthobdellids is interpreted. Sanguivory is seen to have been lost at least twice.


Phytotaxa ◽  
2013 ◽  
Vol 119 (1) ◽  
pp. 1 ◽  
Author(s):  
JULIANA SANTOS-SILVA ◽  
ANA MARIA GOULART DE AZEVEDO TOZZI ◽  
MARCELO FRAGOMENI SIMON ◽  
NAZARETH GUEDES URQUIZA ◽  
MATÍAS MORALES

With more than 500 species, Mimosa L. is one of the largest genera of the Leguminosae. It exhibits considerable trichome diversity among species. Trichome types have been used as diagnostic characters, but some are not well known and have been poorly described in taxonomic works, causing some difficulties for species identification and description. The morphology of trichomes of 35 species was studied using scanning electron microscopy and light microscopy to define the types of trichomes precisely. An ancestral character state reconstruction using a densely-sampled phylogeny of the genus was performed in order to investigate the evolution of trichome types in Mimosa. Two basic types of trichomes can be distinguished: glandular and non-glandular. The glandular trichomes can be sessile or stalked. The non-glandular trichomes can be unbranched or branched. Unbranched trichomes are unicellular and conical or cylindrical, whereas branched trichomes are multicellular and verruciform, medusiform, plumose, barbellate, stellate, stellate-lepidote, or lepidote. Character optimization analysis suggests that glandular and branched trichomes are derived and evolved independently in different lineages within Mimosa. The ancestral condition in Mimosa was probably non-glandular and unbranched trichomes, which was retained from piptadenioid ancestors. Our study provides a first insight into the evolutionary history of trichome morphology in the genus. Despite high levels of homoplasy, trichome morphology offers a set of characters that can be used for differentiating species and species groups in combination with other characters. 


2003 ◽  
Vol 9 ◽  
pp. 11-36 ◽  
Author(s):  
Lisa E. Park ◽  
R. Douglas Ricketts

The Ostracoda are one of the most diverse arthropod groups alive today; they also have a tremendous fossil record. Because of their widespread environmental distributions, small size and carbonate shell, they have become extremely useful biostratigraphic and paleoenvironmental proxy indicators, particularly in nonmarine environments. Despite this utility, little is known about the phylogenetic history of this important group. We reconstructed a phylogenetic history of the major orders and suborders of Ostracoda in order to test the legitimacy of current classification schemes, determine if it is possible for ostracodes to have a Precambrian origin, and test the fidelity of some of the major morphological characters that have documented trends of either increased complexity, such as the hinge and marginal pore canals, or reduction in segments, such as the adductor muscle scar.In our phylogenetic analysis to test taxonomic fidelity, we coded seven morphological hard part characters for nine taxa from the orders Archaeocopida, Leperditicopida, Palaeocopida, Podocopida, and Myodocopida. A parsimony analysis was performed using PAUP (v. 4.0) yielding 4 trees of 17 steps with low levels of homoplasy and a strong phylogenetic signal. A majority rule consensus tree indicates there is not complete agreement between the standard classification scheme and the phylogeny produced by the characters used to establish the classification. In our complete analysis of Ostracoda, we coded 28 morphological characters that included 14 hard part and 14 soft part characters for twelve taxa that include the Archaeocopida, Leperditicopida, Podocopida, and Myodocopida. A parsimony analysis was completed using PAUP (v. 4.0) yielding 1 tree of 125 steps with low levels of homoplasy and a strong phylogenetic signal. An unrooted analysis of this character set has the Cambrian Archaeopodocopida and the Ordovician-Devonian Leperditicopida in an unresolved polytomy with much younger groups such as the Myodocopina, suggesting a much deeper split in the lineage and a possible Precambrian origin for the Ostracoda. Testing the various character state acquisitions over the tree indicates that the hinge does not show an increase in complexity within a phylogenetic context, while the adductor muscle scars do show a significant trend of decrease in complexity across the tree topology. The marginal pore canals, which are functionally tied to osmoregulation as well as carapace secretion, are extremely homoplastic, indicating that this character, which is related to nonmarine invasions and tolerances, was acquired many times throughout the evolutionary history of Ostracoda.By creating an evolutionary framework for the Ostracoda such as is presented here, we can further assess character state acquisition, and how it functionally and evolutionarily relates to ostracode paleoenvironmental tolerances. The framework will not only allow us to understand the overall evolution ofthis group but will also allow us to compare the history of the ostracode clade with other groups that also have a history ofmarine and nonmarine transitions.


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