scholarly journals How to Render Species Comparable Taxonomic Units Through Deep Time: a Case Study on Intraspecific Osteological Variability in Extant and Extinct Lacertid Lizards

2021 ◽  
Author(s):  
Emanuel Tschopp ◽  
James G Napoli ◽  
Lukardis C M Wencker ◽  
Massimo Delfino ◽  
Paul Upchurch
Keyword(s):  
Species Delimitation ◽  
Intraspecific Variability ◽  
Distinct Species ◽  
Deep Time ◽  
Extinct Species ◽  
Naturally Occurring ◽  
Extant Species ◽  
Lacertid Lizards ◽  
Single Genus

Abstract Generally, the species is considered to be the only naturally occurring taxon. However, species recognised and defined using different species delimitation criteria cannot readily be compared, impacting studies of biodiversity through Deep Time. This comparability issue is particularly marked when comparing extant with extinct species, because the only available data for species delimitation in fossils is derived from their preserved morphology, which is generally restricted to osteology in vertebrates. Here, we quantify intraspecific, intrageneric, and intergeneric osteological variability in extant species of lacertid lizards using pairwise dissimilarity scores based on a dataset of 253 discrete osteological characters for 99 specimens referred to 24 species. Variability is always significantly lower intraspecifically than between individuals belonging to distinct species of a single genus, which is in turn significantly lower than intergeneric variability. Average values of intraspecific variability and associated standard deviations are consistent (with few exceptions), with an overall average within a species of 0.208 changes per character scored. Application of the same methods to six extinct lacertid species (represented by 40 fossil specimens) revealed that intraspecific osteological variability is inconsistent, which can at least in part be attributed to different researchers having unequal expectations of the skeletal dissimilarity within species units. Such a divergent interpretation of intraspecific and interspecific variability among extant and extinct species reinforces the incomparability of the species unit. Lacertidae is an example where extant species recognised and defined based on a number of delimitation criteria show comparable and consistent intraspecific osteological variability. Here, as well as in equivalent cases, application of those skeletal dissimilarity values to palaeontological species delimitation potentially provides a way to ameliorate inconsistencies created by the use of morphology to define species.

scholarly journals Barcoding type specimens helps to identify synonyms and an unnamed new species in Eumunida Smith, 1883 (Decapoda : Eumunididae)

2011 ◽  
Vol 25 (4) ◽  
pp. 322 ◽  
Author(s):  
Nicolas Puillandre ◽  
Enrique Macpherson ◽  
Josie Lambourdière ◽  
Corinne Cruaud ◽  
Marie-Catherine Boisselier-Dubayle ◽  
...  
Keyword(s):  
Species Delimitation ◽  
Preliminary Analysis ◽  
Taxonomic Revision ◽  
Distinct Species ◽  
Molecular Clusters ◽  
Dna Barcodes ◽  
Type Specimens ◽  
Important Challenge ◽  
Identification Tool

The primary purpose of DNA-barcoding projects is to generate an efficient expertise and identification tool. This is an important challenge to the taxonomy of the 21st century, as the demand increases and the expert capacity does not. However, identifying specimens using DNA-barcodes requires a preliminary analysis to relate molecular clusters to available scientific names. Through a case study of the genus Eumunida (Decapoda : Eumunididae), we illustrate how naming molecule-based units, and thus providing an accurate DNA-based identification tool, is facilitated by sequencing type specimens. Using both morphological and unlinked molecular markers (COI and 28S genes), we analysed 230 specimens from 12 geographic areas, covering two-thirds of the known diversity of the genus, including type specimens of 13 species. Most hypotheses of species delimitation are validated, as they correspond to molecular units linked to only one taxonomic name (and vice versa). However, a putative cryptic species is also revealed and three entities previously named as distinct species may in fact belong to a single one, and thus need to be synonymised. Our analyses, which integrate the current naming rules, enhance the α-taxonomy of the genus and provide an effective identification tool based on DNA-barcodes. They illustrate the ability of DNA-barcodes, especially when type specimens are included, to pinpoint where a taxonomic revision is needed.

scholarly journals The late Miocene Phractocephalus catfish (Siluriformes: Pimelodidae) from Urumaco, Venezuela: additional specimens and reinterpretation as a distinct species

2003 ◽  
Vol 1 (2) ◽  
pp. 97-109 ◽  
Author(s):  
John G. Lundberg ◽  
Orangel Aguilera
Keyword(s):  
Coastal Region ◽  
Distinct Species ◽  
Large River ◽  
Fossil Species ◽  
Extinct Species ◽  
Upper Miocene ◽  
Tooth Plate ◽  
Extant Species ◽  
Lateral Ethmoid ◽  
Pectoral Spine

Based on additional specimens the fossil pimelodid catfish from the upper Miocene Urumaco Formation, Falcón State, Venezuela originally assigned to the extant species Phractocephalus hemioliopterus is described as a new, extinct species. †Phractocephalus nassi n. sp. is diagnosed by the following combination of characters: 1) posterior half of frontals and anterior half of supraoccipital with elongate, coarse ridges and sulci in addition to reticulating ridges and subcircular pits; 2) very broad and ornamented mesethmoid bone; 3) lateral ethmoid margin convex and eliminating orbital notch but not projecting far anteriorly over palatine condyle; 4) anterior cranial fontanelle closed or represented by a small pit; 5) supraoccipital process rounded laterally and posterolaterally, concave posteriorly and completely concealing Weberian complex in dorsal view; 6) opercle covered with reticulating ridges and pits; 7) cleithrum coarsely ornamented along ventral edge and bulging outward lateral to spine articulation; 8) pectoral spine mostly ornamented with coarse ridges and sulci. †Phractocephalus nassi is compared to modern P. hemioliopterus and an undescribed extinct species from the upper Miocene Solimões Formation, Acre, Brazil. New diagnostic characters of Phractocephalus are presented that apply to the modern and fossil species, including: 1) ornamentation of skull, pectoral girdle and fin spines comprising a coarse meshwork of reticulating ridges surrounding rounded pits plus some elongate ridges and sulci; 2) supraoccipital posterior process greatly expanded laterally and posteriorly behind occipital wall; 3) lateral ethmoid and sphenotic broadly sutured behind eye; 4) anterior cranial fontanelle reduced or completely closed and posterior cranial fontanelle closed; 5) vomerine tooth plate large, roughly pentagonal to triangular in form, and with fine teeth. Today Phractocephalus ranges widely throughout the lowland Orinoco, Amazon and Essequibo basins. However, the genus does not occur west or north of the Andes or Venezuelan coastal ranges. Recognizing the Urumaco Phractocephalus as a distinct species does not alter the obvious conclusion that this catfish marks a large river connection between the Caribbean coastal region and the Orinoco system during at least part of the Neogene. Other Urumaco fossils show this same biogeographic relationship.

scholarly journals Phylogenetic value of jaw elements of lacertid lizards (Squamata: Lacertoidea): a case study with Oligocene material from France

Cladistics ◽  
2021 ◽  
Author(s):  
Lukardis Charlotte Marie Wencker ◽  
Emanuel Tschopp ◽  
Andrea Villa ◽  
Marc Louis Augé ◽  
Massimo Delfino
Keyword(s):  
Lacertid Lizards

West Palearctic cobras of the genus Naja (Serpentes: Elapidae): interrelationships among extinct and extant species

1990 ◽  
Vol 11 (4) ◽  
pp. 385-400 ◽  
Author(s):  
Jean-Claude Rage ◽  
Zbigniew Szyndlar
Keyword(s):  
Monophyletic Group ◽  
Close Relative ◽  
African Species ◽  
Naja Naja ◽  
Extinct Species ◽  
Extant Species ◽  
Asiatic Species ◽  
Extinct Genus

AbstractSome basic osteological cranial features of living and fossil members of the genus Naja are described. The extinct genus Palaeonaja Hoffstetter, 1939, is synonymized with the modern Naja Laurenti, 1768, and the extinct species Palaeonaja crassa Hoffstetter, 1939, is synonymized with Naja romani (Hoffstetter, 1939). Anatomically, the genus Naja can be divided into two main complexes, composed of: (1) living African species, N. antiqua from the Moroccan Miocene, and N. iberica from the Spanish Miocene; (2) living Asiatic species and N. romani from the Miocene of France, Austria, and Ukraine. Living members of the Asiatic complex make up a monophyletic group; they belong to at least three distinct lineages: N. oxiana, N. naja s.s. ( = N. naja naja), and the remaining taxa named here informally the 'East Asiatic Naja'. The African complex is thought to be most primitive and perhaps paraphyletic; Africa is presumed to be the centre of earliest radiation of the genus. The precise relationships of Walterinnesia, a close relative of Naja occupying the area between Asiatic and African ranges of Naja, remain unclear.

scholarly journals Evolution of halophytes: multiple origins of salt tolerance in land plants

2010 ◽  
Vol 37 (7) ◽  
pp. 604 ◽  
Author(s):  
Timothy J. Flowers ◽  
Hanaa K. Galal ◽  
Lindell Bromham
Keyword(s):  
Salt Tolerance ◽  
Novel Species ◽  
Complex Trait ◽  
Land Plants ◽  
Salt Tolerant ◽  
Physiological Mechanisms ◽  
Multiple Origins ◽  
Naturally Occurring ◽  
Tolerant Plants

The evolution of salt tolerance is interesting for several reasons. First, since salt-tolerant plants (halophytes) employ several different mechanisms to deal with salt, the evolution of salt tolerance represents a fascinating case study in the evolution of a complex trait. Second, the diversity of mechanisms employed by halophytes, based on processes common to all plants, sheds light on the way that a plant’s physiology can become adapted to deal with extreme conditions. Third, as the amount of salt-affected land increases around the globe, understanding the origins of the diversity of halophytes should provide a basis for the use of novel species in bioremediation and conservation. In this review we pose the question, how many times has salt tolerance evolved since the emergence of the land plants some 450–470 million years ago? We summarise the physiological mechanisms underlying salt-tolerance and provide an overview of the number and diversity of salt-tolerant terrestrial angiosperms (defined as plants that survive to complete their life cycle in at least 200 mM salt). We consider the evolution of halophytes using information from fossils and phylogenies. Finally, we discuss the potential for halophytes to contribute to agriculture and land management and ask why, when there are naturally occurring halophytes, it is proving to be difficult to breed salt-tolerant crops.

Communicating emotions in L2 Chinese: Talk in the dorm during study abroad

2018 ◽  
Vol 4 (2) ◽  
pp. 337-359
Author(s):  
Qian Wu
Keyword(s):  
Study Abroad ◽  
Native Speakers ◽  
Human Interaction ◽  
Emotional Expressions ◽  
Genetic Method ◽  
Naturally Occurring ◽  
Expression Of Emotion ◽  
History Of ◽  
Oral Interaction

AbstractCommunication of emotion is at the heart of human interaction. For second language (L2) learners, the ability to communicate one’s emotion is crucial, especially in the context of study abroad when they are in frequent contact with native speakers. The aim of the case study is to investigate how an American sojourner Puppies and her Chinese roommate Kiki (both pseudonyms) participated in conversational narratives in the dormitory to construct emotions, and how the contextualized interaction facilitated Puppies’ development of a linguistic repertoire for the expression of emotion in Chinese. Informed by Vygotskian sociocultural theory, the study followed the genetic method in tracing the history of Puppies’ Chinese emotional repertoire across the semester, thereby elucidating the language developmental processes in the situated oral interaction. Audio-recorded everyday interaction in the dorm is triangulated by Puppies’ responses to the pre- and post-Mandarin Awareness Interview and interviews with Puppies and Kiki. Analysis revealed that the contextualized dorm talk provided abundant L2 resources for Puppies to develop a L2 emotional repertoire, especially fear-related emotion expressions. A discrepancy in the product of development as gleaned from the Mandarin Awareness Interview, and the process of development as seen in the naturally occurring dorm talk, suggests that Puppies’ use or non-use of local emotional expressions could be mediated by her partial understanding of the forms and the speech style and identity she wished to assume.

Specific features of supramolecular organisation and hydrogen bonding in proline cocrystals: a case study of fenamates and diclofenac

CrystEngComm ◽  
2018 ◽  
Vol 20 (43) ◽  
pp. 6970-6981 ◽  
Author(s):  
Artem O. Surov ◽  
Alexander P. Voronin ◽  
Mikhail V. Vener ◽  
Andrei V. Churakov ◽  
German L. Perlovich
Keyword(s):  
Hydrogen Bonding ◽  
Amino Acid ◽  
Naturally Occurring ◽  
Supramolecular Organisation

New zwitterionic cocrystals of fenamate drugs and diclofenac with the naturally occurring amino acid l-proline have been obtained and thoroughly characterised by a variety of experimental and theoretical techniques.

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