scholarly journals Hyperphalangy in a new sinemydid turtle from the Early Cretaceous Jehol Biota

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5371 ◽  
Author(s):  
Shuai Shao ◽  
Lan Li ◽  
Yang Yang ◽  
Chang-Fu Zhou

Hyperphalangy is a rare condition in extant aquatic turtles, and mainly limited to soft-shelled turtles. Here we report a new freshwater turtle,Jeholochelys lingyuanensisgen. et sp. nov. from the Early Cretaceous Jehol Biota of western Liaoning, China. This new turtle is characterized by a hyperphalangy condition with one additional phalanx in pedal digit V, rather than the primitive condition (phalangeal formula: 2-3-3-3-3) of crown turtles.J. lingyuanensisis recovered with other coexisting turtles in the family Sinemydidae in the phylogenetic analysis. This discovery further confirms that hyperphalangy occurred multiple times in the early evolutionary history of the crown turtles. Hyperphalangy is possibly a homoplasy inJeholochelysand the soft-shelled turtles to adapt to the aquatic environments.

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Takuya Imai ◽  
Yoichi Azuma ◽  
Soichiro Kawabe ◽  
Masateru Shibata ◽  
Kazunori Miyata ◽  
...  

AbstractThe Early Cretaceous basal birds were known largely from just two-dimensionally preserved specimens from north-eastern China (Jehol Biota), which has hindered our understanding of the early evolution of birds. Here, we present a three-dimensionally-preserved skeleton (FPDM-V-9769) of a basal bird from the Early Cretaceous of Fukui, central Japan. Unique features in the pygostyle and humerus allow the assignment of FPDM-V-9769 to a new taxon, Fukuipteryx prima. FPDM-V-9769 exhibits a set of features comparable to that of other basalmost birds including Archaeopteryx. Osteohistological analyses indicate that FPDM-V-9769 is subadult. Phylogenetic analyses resolve F. prima as a non-ornithothoracine avialan basal to Jeholornis and outgroup of the Pygostylia. This phylogenetic result may imply a complex evolutionary history of basal birds. To our knowledge, FPDM-V-9769 represents the first record of the Early Cretaceous non-ornithothoracine avialan outside of the Jehol Biota and increases our understanding of their diversity and distribution during the time.


1990 ◽  
Vol 3 (1) ◽  
pp. 145
Author(s):  
DJ Colgan

This paper is a review of the use of information regarding the presence of duplicate genes and their regulation in systematics. The review concentrates on data derived from protein electrophoresis and restriction fragment length polymorphism analysis. The appearance of a duplication in a subset of a group of species implies that the members of the subset belong to the same clade. Suppression of the duplication may render this clade apparently paraphyletic, but may itself be informative of relations within the lineage through patterns of loss of expression in all, or some tissues, or through restrictions of the formation of functional heteropolymers in polymeric enzymes. Examples are given of studies which have used such information to establish phylogenetic hypotheses at the family level, to identify an auto- or allo-polyploid origin of polyploid species and to determine whether there have been single or multiple origins of such species. The likelihood of homoplasy in the patterns of appearance and regulation of duplicates depends on the molecular basis of the duplication. In particular, the contrast between the expected consequences of tandem duplication and the expression of pseudogenes emphasises the value of determining the mechanism of the original duplication. Many instances of sporadic gene duplication are now known, and polyploidisation is a common event in the evolutionary history of both plants and animals. So the opportunities to discover duplicationrelated characters will arise in many systematic studies. A program is presented to increase the chances that such useful information will be recognisable during the studies.


1993 ◽  
Vol 67 (4) ◽  
pp. 549-570 ◽  
Author(s):  
Bruce S. Lieberman

Phylogenetic parsimony analysis was used to classify the Siegenian–Eifelian “Metacryphaeus group” of the family Calmoniidae. Thirty-eight exoskeletal characters for 16 taxa produced a shortest-length cladogram with a consistency index of 0.49. A classification based on retrieving the structure of this cladogram recognizes nine genera: Typhloniscus Salter, Plesioconvexa n. gen., Punillaspis Baldis and Longobucco, Eldredgeia n. gen., Clarkeaspis n. gen., Malvinocooperella n. gen., Wolfartaspis Cooper, Plesiomalvinella Lieberman, Edgecombe, and Eldredge (used to represent the malvinellid clade), and Metacryphaeus Reed. The malvinellid clade is most closely related to a revised monophyletic Metacryphaeus. Typhloniscus is the basal member of the “Metacryphaeus group,” and the monotypic Wolfartaspis is sister to the clade containing the malvinellids and Metacryphaeus. Six new species are diagnosed: Punillaspis n. sp. A, “Clarkeaspis” gouldi, Clarkeaspis padillaensis, Malvinocooperella pregiganteus, Metacryphaeus curvigena, and Metacryphaeus branisai. Primitively, this group has South African and Andean affinities, and its evolutionary history suggests rapid diversification. In addition, evolutionary patterns in this group, and the distribution of character reversals, call into question certain notions about the nature of adaptive radiations. The distributions of taxa may answer questions about the number of marine transgressive/regressive cycles in the Emsian–Eifelian of the Malvinokaffric Realm.


2021 ◽  
Author(s):  
Keerthic Aswin ◽  
Srinivasan Ramachandran ◽  
Vivek T Natarajan

AbstractEvolutionary history of coronaviruses holds the key to understand mutational behavior and prepare for possible future outbreaks. By performing comparative genome analysis of nidovirales that contain the family of coronaviruses, we traced the origin of proofreading, surprisingly to the eukaryotic antiviral component ZNFX1. This common recent ancestor contributes two zinc finger (ZnF) motifs that are unique to viral exonuclease, segregating them from DNA proof-readers. Phylogenetic analyses indicate that following acquisition, genomes of coronaviruses retained and further fine-tuned proofreading exonuclease, whereas related families harbor substitution of key residues in ZnF1 motif concomitant to a reduction in their genome sizes. Structural modelling followed by simulation suggests the role of ZnF in RNA binding. Key ZnF residues strongly coevolve with replicase, and the helicase involved in duplex RNA unwinding. Hence, fidelity of replication in coronaviruses is a result of convergent evolution, that enables maintenance of genome stability akin to cellular proofreading systems.


1984 ◽  
Vol 8 ◽  
pp. 182-198
Author(s):  
Catherine Badgley

The evolutionary history of humans is well understood in outline, compared to that of many other groups of mammals. But human evolution remains enigmatic in its details, and these are compelling both scientifically and personally because they relate to the biological uniqueness of humans. Humans are placed in the primate family Hominidae, which, in traditional classifications, contains a single living species, Homo sapiens. The closest living relatives of humans are great apes: the chimpanzees Pan paniscus and Pan troglodytes, the gorilla Gorilla gorilla, and the orangutan Pongo pygmaeus. These apes have traditionally been placed in the family Pongidae as the sister group of Hominidae. Living Hominidae and Pongidae, together with Hylobatidae (gibbons) comprise the modern representatives of the primate suborder Hominoidea.


Symbiosis ◽  
2020 ◽  
Vol 80 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Ewa Sajnaga ◽  
Waldemar Kazimierczak

AbstractEntomopathogenic bacteria from the genera Photorhabdus and Xenorhabdus are closely related Gram-negative bacilli from the family Enterobacteriaceae (γ-Proteobacteria). They establish obligate mutualistic associations with soil nematodes from the genera Steinernema and Heterorhabditis to facilitate insect pathogenesis. The research of these two bacterial genera is focused mainly on their unique interactions with two different animal hosts, i.e. nematodes and insects. So far, studies of the mutualistic bacteria of nematodes collected from around the world have contributed to an increase in the number of the described Xenorhabdus and Photorhabdus species. Recently, the classification system of entomopatogenic nematode microsymbionts has undergone profound revision and now 26 species of the genus Xenorhabdus and 19 species of the genus Photorhabdus have been identified. Despite their similar life style and close phylogenetic origin, Photorhabdus and Xenorhabdus bacterial species differ significantly in e.g. the nematode host range, symbiotic strategies for parasite success, and arrays of released antibiotics and insecticidal toxins. As the knowledge of the diversity of entomopathogenic nematode microsymbionts helps to enable the use thereof, assessment of the phylogenetic relationships of these astounding bacterial genera is now a major challenge for researchers. The present article summarizes the main information on the taxonomy and evolutionary history of Xenorhabdus and Photorhabdus, entomopathogenic nematode symbionts.


1938 ◽  
Vol 57 ◽  
pp. 221-227
Author(s):  
James Small

Applying Udny Yule's formulæ (1924) to the Compositæ, Small (1937) found that the average ages in doubling periods (Dp-ages) of the tribes of Compositæ, when plotted against a time-scale, gave points on an exponential curve called the BAT curve. If this curve is characteristic of average families of Angiosperms it should be possible to place the Dp-ages of tribes within other families on this curve as plotted against geological time, and thus obtain an order of geological origin which is quite independent of actual fossil records and which can be checked against any facts known concerning the evolutionary history of the family.


2019 ◽  
Vol 158 (2) ◽  
pp. 98-105 ◽  
Author(s):  
Suziane A. Barcellos ◽  
Rafael Kretschmer ◽  
Marcelo S. de Souza ◽  
Alice L. Costa ◽  
Tiago M. Degrandi ◽  
...  

As in many other bird groups, data on karyotype organization and distribution of repetitive sequences are also lacking in species belonging to the family Hirundinidae. Thus, in the present study, we analyzed the karyotypes of 3 swallow species (Progne tapera, Progne chalybea, and Pygochelidon cyanoleuca) by Giemsa and AgNOR staining, C-banding, and FISH with 11 microsatellite sequences. The diploid chromosome number was 2n = 76 in all 3 species, and NORs were observed in 2 chromosome pairs each. The microsatellite distribution pattern was similar in both Progne species, whereas P. cyanoleuca presented a distinct organization. These repetitive DNA sequences were found in the centromeric, pericentromeric, and telomeric regions of the macrochromosomes, as well as in 2 interstitial blocks in the W chromosome. Most microchromosomes had mainly telomeric signals. The Z chromosome displayed 1 hybridization signal in P. tapera but none in the other species. In contrast, the W chromosome showed an accumulation of different microsatellite sequences. The swallow W chromosome is larger than that of most Passeriformes. The observed enlargement in chromosome size might be explained by these high amounts of repetitive sequences. In sum, our data highlight the significant role that microsatellite sequences may play in sex chromosome differentiation.


2020 ◽  
Vol 287 (1928) ◽  
pp. 20200629 ◽  
Author(s):  
Xiumei Lu ◽  
Bo Wang ◽  
Weiwei Zhang ◽  
Michael Ohl ◽  
Michael S. Engel ◽  
...  

Mantidflies (Mantispidae) are an unusual and charismatic group of predatory lacewings (Neuroptera), whereby the adults represent a remarkable case of morphological and functional convergence with praying mantises (Mantodea). The evolutionary history of mantidflies remains largely unknown due to a scarcity of fossils. Here, we report the discovery of a highly diverse palaeofauna of mantidflies from the mid-Cretaceous (lowermost Cenomanian) of Myanmar. The raptorial forelegs of these mantidflies possess highly divergent morphological modifications, some of which are unknown among modern mantidflies, e.g. the presence of forked basal profemoral spines or even the complete loss of foreleg spine-like structures. A phylogenetic analysis of Mantispidae reveals a pattern of raptorial foreleg evolution across the family. The high species diversity and disparate foreleg characters might have been driven by diverse niches of predator–prey interplay in the complex tropical forest ecosystem of the mid-Cretaceous.


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