A new genus of rhizodontid (Sarcopterygii, Tetrapodomorpha) from the Lower Carboniferous Horton Bluff Formation of Nova Scotia, and the evolution of the lower jaws in this group

2005 ◽  
Vol 42 (8) ◽  
pp. 1481-1499 ◽  
Author(s):  
Martin D Brazeau

Letognathus gen. nov. is described from the Lower Carboniferous (Tournaisian) Horton Bluff Formation. Included in this genus is the species Letognathus hardingi (Dawson 1868), which was originally assigned toRhizodus and later toStrepsodus, but it is distinct from these genera in tooth morphology and the presence of several more primitive rhizodontid characters. By contrast with these latter more derived genera, the parasymphysial plate contacts the first coronoid; the first coronoid bears a row of lingually deflected teeth, the tooth striations occur around the entire circumference of the crown and are much finer and less regular than those ofStrepsodus, and marginal tooth row reaches anteriorly to the dentary symphysis. Phylogenetic analysis indicates that rhizodontid jaws primitively bear symphysial tusks; slender recumbent teeth; an anterior projection of the dentary over the anteromesial depression for the median symphysial plate and shows the highly derived jaws ofStrepsodus andRhizodus evolved within the Rhizodontida, rather than as primitive characters for the group. This new jaw material supports earlier models of mandibular kinesis and shows that the coronoid fangs were oriented such as to facilitate kinesis. Rhizodontid jaw evolution seems to be marked by parallelisms with tristichopterids and early tetrapods.

2010 ◽  
Vol 47 (6) ◽  
pp. 901-912 ◽  
Author(s):  
David M. Mazierski ◽  
Robert R. Reisz

Ianthasaurus hardestiorum , a basal edaphosaurid from the Upper Pennsylvanian of Garnett, Kansas, has been described on the basis of two incomplete, juvenile specimens and a series of disarticulated vertebral elements. New skeletal material of this poorly known species includes previously unknown cranial elements, increasing our knowledge of the anatomy and variation in this taxon. The complete ossification of the neural arches and the overall larger size of the vertebrae relative to those previously described indicate that they were part of an adult individual, and marginal tooth morphology resembles more closely that seen in the genus Edaphosaurus . Phylogenetic analysis of edaphosaurid synapsids confirms the hypothesis that Ianthasaurus is a sister-taxon of all other members of the clade. However, the incomplete fossil record of other putative edaphosaurids, such as Lupeosaurus and Glaucosaurus , makes full resolution of their phylogenetic interrelationships difficult to assess.


Phytotaxa ◽  
2013 ◽  
Vol 146 (1) ◽  
pp. 1 ◽  
Author(s):  
PETER B. HEENAN ◽  
ROB D. SMISSEN

The generic taxonomy of the Nothofagaceae is revised. We present a new phylogenetic analysis of morphological characters and map these characters onto a recently published phylogenetic tree obtained from DNA sequence data. Results of these and previous analyses strongly support the monophyly of four clades of Nothofagaceae that are currently treated as subgenera of Nothofagus. The four clades of Nothofagaceae are robust and well-supported, with deep stem divergences, have evolutionary equivalence with other genera of Fagales, and can be circumscribed with morphological characters. We argue that these morphological and molecular differences are sufficient for the four clades of Nothofagaceae to be recognised at the primary rank of genus, and that this classification will be more informative and efficient than the currently circumscribed Nothofagus with four subgenera.        Nothofagus is recircumscribed to include five species from southern South America, Lophozonia and Trisyngyne are reinstated, and the new genus Fuscospora is described. Fuscospora and Lophozonia, with six and seven species respectively, occur in New Zealand, southern South America and Australia. Trisyngyne comprises 25 species from New Caledonia, Papua New Guinea and Indonesia. New combinations are provided where necessary in each of these genera.


2010 ◽  
Vol 84 (4) ◽  
pp. 695-708 ◽  
Author(s):  
Andrea Jiménez-Sánchez ◽  
Robert L. Anstey ◽  
Beatriz Azanza

Zootaxa ◽  
2021 ◽  
Vol 4964 (2) ◽  
pp. 330-344
Author(s):  
YEHUDA BENAYAHU ◽  
LEEN P. VAN OFWEGEN ◽  
J. P. RUIZ ALLAIS ◽  
CATHERINE S. MCFADDEN

Because of the problematical identity and status of the type of the xeniid soft coral genus Cespitularia Milne-Edwards & Haime, 1850, the species C. stolonifera Gohar, 1938 is revised. Examination of the type colonies has led to the establishment of the new genus Unomia gen. n. which is described and depicted. This genus features a stalk, commonly divided into branches featuring a diffuse polypiferous part consisting of distal clustered polyps and proximal individual ones on the stalk or the basal membranous part of the colonies. The sclerites are ellipsoid platelets composed of dendritic calcite rods whose tips are distinct on the surface of the platelets. Freshly collected material from Venezuelan reefs where the species is invasive was subjected to molecular phylogenetic analysis, the results of which substantiate the taxonomic assignment of the new genus under U. stolonifera comb. n. A new species, U. complanatis, from Japan and Green Island (Taiwan) is described and further illustrates the extent of the interspecific morphological variation within the genus. The results reveal that the biogeographic distribution of Unomia gen. n. includes Pacific Ocean reefs in addition to the previously reported invaded Caribbean reefs. 


Zootaxa ◽  
2010 ◽  
Vol 2481 (1) ◽  
Author(s):  
CARLOS MOLINERI

The 12 species previously placed in Tortopus together with 3 species newly described here, are revised and included in a phylogenetic analysis. Based on synapomorphic characters on the nymphs and adults of both sexes, Tortopus is restricted to T. igaranus Needham & Murphy, T. circumfluus Ulmer, T. harrisi Traver, T. zottai (Navás), T. bellus Lugo-Ortiz & McCafferty, and T. arenales sp. nov., and the genus is defined by: female parastyli receptors with long furrows anterior to sockets; penes entirely flattened; male ninth abdominal sternum almost separated in two portions by a median notch; mesosternum with furcasternal protuberances contiguous only on basal corner; and nymphs with two subapical tubercles on mandibular tusks. Tortopsis is newly described for T. bruchianus (Navás), T. limoncocha sp. nov., T. obscuripennis (Domínguez), T. parishi (Banks), T. primus (McDunnough), T. puella (Pictet), T. sarae (Domínguez), T. spatula sp. nov., and T. unguiculatus (Ulmer). Tortopsis is characterized by: R sector of female fore wing without additional veins between R 2 and IR; female parastyli receptors C or V-shaped, with sockets opening towards median line; male gonopore associated with a claw-like structure; penes separated from the base; parastyli more than 5 times length of pedestals; parastyli curved in lateral view; nymphs with a single subapical tubercle on mandibular tusks. The study of available type material permitted inclusion of comparative diagnoses, with figures and redescriptions as needed. The male imago of the type species of Tortopus (T. igaranus Needham & Murphy) is described for the first time, as are the female adults of Tortopus bellus Lugo-Ortiz & McCafferty and T. harrisi Traver. Three new Neotropical species based on male and female adults are described: Tortopus arenales and Tortopsis limoncocha from Ecuador, and Tortopsis spatula from Colombia. Keys to separate the adults and nymphs of the genera of Polymitarcyidae, and for male and female adults of all the species of Tortopus and Tortopsis are presented, as well as line drawings, pictures and SEM photographs of important structures.


2018 ◽  
Author(s):  
Robert Boessenecker ◽  
R. Ewan Fordyce

The early evolution of toothless baleen whales (Chaeomysticeti) remains elusive despite a robust record of Eocene-Oligocene archaeocetes and toothed mysticetes. Eomysticetids, a group of archaic longirostrine and putatively toothless baleen whales fill in a crucial morphological gap between well-known toothed mysticetes and more crownward Neogene Mysticeti. A historically important but perplexing cetacean is “Mauicetus” lophocephalus (upper Oligocene South Island, New Zealand). The discovery of new skulls and skeletons of eomysticetids from the Oligocene Kokoamu Greensand and Otekaike Limestone permit a redescription and modern reinterpretation of “Mauicetus” lophocephalus, and indicating that this species may have retained adult teeth. A new genus and species, Tokarahia kauaeroa, is erected on the basis of a well-preserved subadult to adult skull with mandibles, tympanoperiotics, and cervical and thoracic vertebrae, ribs, sternum, and forelimbs from the Otekaike Limestone (>25.2 Ma). “Mauicetus” lophocephalus is relatively similar and recombined as Tokarahia lophocephalus. Phylogenetic analysis supports inclusion of Tokarahia within the Eomysticetidae alongside Eomysticetus, Micromysticetus, Yamatocetus, and Tohoraata, and strongly supports monophyly of Eomysticetidae. Tokarahia lacked extreme rostral kinesis of extant Mysticeti and primitively retained a delicate archaeocete-like posterior mandible and synovial temporomandibular joint, suggesting that Tokarahia was capable of at most, limited lunge feeding in contrast to extant Balaenopteridae, and utilized an alternative as-yet unspecified feeding strategy.


2002 ◽  
Vol 33 (2) ◽  
pp. 185-237 ◽  
Author(s):  
Jason P.W. Hall

AbstractA phylogenetic revision of the Neotropical riodinid genus Calydna Doubleday and relatives is presented. A phylogenetic analysis for all twenty species of Calydna using thirty-eight characters of adult morphology generated four most parsimonious cladograms. Calydna is characterised to contain eighteen species, divided here into three monophyletic species groups with the relationship caieta group + (thersander group + hiria group). A new genus Echydna Hall gen. n. is described for the most basal clade, containing chaseba Hewitson and punctata C. & R. Felder, which are transferred from Calydna (combs. n.). The taxonomy, morphology, biogeography and biology of both genera are discussed, locality data is listed and mapped, and the adults and male and female genitalia are illustrated for all species. Concealed male abdominal androconial scales, which phylogenetically unite the thersander and hiria groups, are reported for the first time outside of the tribes Symmachiini and Nymphidiini. Two new species are described, Calydna jeannea sp. n. and Calydna nicolayi sp. n., and the replacement name fissilisima is provided for the unavailable name fissilis Stichel; maculosa Bates is transferred from Calydna to Callistium Stichel (comb. n.).


2021 ◽  
pp. SP521-2020-249
Author(s):  
Daran Zheng ◽  
Edmund A. Jarzembowski ◽  
De Zhuo ◽  
André Nel

AbstractHemiphlebiidae are the most basal lestomorphan family following the latest phylogenetic analysis of the Zygoptera: this unique damselfly family today contains one relict species found in the wetlands of Australia. It was, however, very diverse and widespread during the Mesozoic. Nevertheless, very few species were known obscuring the origination and early evolution of the family. Here we propose a new stem hemiphlebioid taxon (Protohemiphlebiidae Zheng, Jarzembowski & Nel, fam. nov.) based on a new genus and two species: Protohemiphlebia zhangi Zheng, Jarzembowski & Nel, sp. nov. and Protohemiphlebia meiyingae Zheng, Jarzembowski & Nel, sp. nov. The new family shares the characters of both Hemiphlebiidae and Coenagrionoidea, but it is more closely related to Hemiphlebiidae in having the pterostigma with a ‘star-shaped’ microsculpture, and AA originating from the wing base slightly distal of Ax0. Protohemiphlebia Zheng, Jarzembowski & Nel, gen. nov. is further considered to belong to the stem group of Hemiphlebioidea, instead of belonging to the Hemiphlebiidae, in possessing pretibial combs and a weakly kinked RP1 below the Pt-brace. The new damselflies will help to calibrate the origin of Hemiphlebiidae, which could be earlier than their current oldest records in the Kimmeridgean (Late Jurassic).


2021 ◽  
Author(s):  
Juan F Cornejo-Franco ◽  
Francisco Flores ◽  
Dimitre Mollov ◽  
diego fernando quito-avila

Abstract The complete sequence of a new viral RNA from babaco (Vasconcellea x heilbornii) was determined. The genome consisted of 4,584 nucleotides organized in two non-overlapping open reading frames (ORFs 1 and 2), a 9-nt-long noncoding region (NCR) at the 5’ terminus and a 1,843 -nt-long NCR at the 3’ terminus. Sequence comparisons of ORF 2 revealed homology to the RNA-dependent-RNA-polymerase (RdRp) of several umbra- and umbra-related viruses. Phylogenetic analysis of the RdRp placed the new virus in a well-supported and cohesive clade that includes umbra-like viruses reported from papaya, citrus, opuntia, maize and sugarcane hosts. This clade shares a most recent ancestor with the umbraviruses but has different genomic features. The creation of a new genus, within the Tombusviridae, is proposed for the classification of these novel viruses.


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