scholarly journals Systematics of Chasmosaurus -  new information from the Peabody Museum skull, and the use of phylogenetic analysis for dinosaur alpha taxonomy

F1000Research ◽  
2015 ◽  
Vol 4 ◽  
pp. 1468
Author(s):  
Nicholas Longrich

The horned dinosaur Chasmosaurus from the late Campanian Dinosaur Park Formation of Alberta, is known from numerous skulls and skeletons, but over a century after its description, the taxonomy of the genus is controversial. Two species, Chasmosaurus belli and C. russelli, are currently recognized, with a third species, C. irvinensis, recently placed in a new genus, Vagaceratops. Here, the Yale Chasmosaurus skull is described, and implications for Chasmosaurus systematics are explored. The Yale skull is intermediate between typical C. belli and C. irvinensis. C. belli-like features include large, triangular lateral epiparietals, large parietal fenestrae, and an emarginate parietal. Yet the skull also exhibits derived features of C. irvinensis, including a posteriorly inclined narial strut, brow horns replaced by rugose bosses, reduced parietal emargination, five pairs of epiparietals, and epiparietals that fuse at their bases and hook forward over the frill. Specimen-level phylogenetic analysis provides a hypothesis of relationships upon which to base the taxonomy of Chasmosaurus. C. belli is paraphyletic with respect to C. irvinensis, and the Peabody skull is closer to C. irvinensis than to other C. belli. The holotype of C. russelli clusters with C. belli, making C. russelli a junior synonym of C. belli. Accordingly, Chasmosaurus can be divided into three species: C. belli, C. irvinensis, and C. priscus sp. nov, including specimens previously referred to C. russelli. The systematics of Chasmosaurus show how specimen level phylogeny can provide an evolutionary framework upon which to establish taxonomies. However, the resulting phylogenies may lead to paraphyletic species and genera.

Zootaxa ◽  
2019 ◽  
Vol 4559 (2) ◽  
pp. 245
Author(s):  
MATHIAS JASCHHOF ◽  
CATRIN JASCHHOF

The taxonomy of several genera of the tribe Dicerurini (subfamily Porricondylinae) is revisited, induced by the discovery of 11 new species in Malaise catches of various provenances. The bulk of the specimens interpreted here is of Swedish origin. Species described as new to science are Desertepidosis grytsjoenensis sp. nov. (from Sweden), D. robusta sp. nov. (Sweden), Linnaeomyia pratensis sp. nov. (Czech Republic), Neurepidosis ekdalensis sp. nov. (Sweden), N. emarginata sp. nov. (Sweden, Czech Republic), N. hybrida sp. nov. (Sweden), Tetraneuromyia brevipalpis sp. nov. (Sweden, Slovak Republic), T. discrepans sp. nov. (Sweden), T. errata sp. nov. (Sweden), and T. lapponica sp. nov. (Sweden). A new genus, Gardenforsia gen. nov., is introduced for G. oelandica sp. nov. (Sweden), a new species with regressive male morphology. The generic definitions of Desertepidosis Mamaev & Soyunov, 1989 (including Ubinomyia Mamaev, 1990 syn. nov. as new junior synonym) and Linnaeomyia Jaschhof & Jaschhof, 2015 are revised. A key to males of Desertepidosis is presented. New information on the morphology and geographic distribution is provided for Linnaeomyia hortensis Jaschhof & Jaschhof, 2015; Tetraneuromyia bulbifera Mamaev, 1964; and T. lamellata Spungis, 1987. 


2010 ◽  
Vol 84 (4) ◽  
pp. 681-694 ◽  
Author(s):  
Nicholas R. Longrich

A new genus of long-horned chasmosaurine ceratopsid is described from the Dinosaur Park Formation (upper Campanian) of Western Canada. Mojoceratops perifania is represented by a skull and a parietal from the Dinosaur Park Formation of Alberta and an isolated parietal from the Dinosaur Park Formation of Saskatchewan. Several other specimens are provisionally referred to this taxon. While Mojoceratops shares many plesiomorphies with Chasmosaurus, the animal lacks the forward-curving parietal epoccipitals and reduced postorbital horns that diagnose the genus Chasmosaurus, and it differs from all other chasmosaurines in exhibiting a prominent sulcus on the anterior margin of the parietal, swellings on the anterodorsal surface of the parietal rami, and a small accessory process on the first parietal epoccipital. Other unusual features include anteriorly extended parietal fenestrae, a broad, heart-shaped frill, and transverse expansion of the postfrontal fontanelle. The type material of “Eoceratops canadensis” and “Chasmosaurus kaiseni” are nondiagnostic and these names are therefore considered nomina dubia, but their morphology is consistent with Mojoceratops and they probably belong to this genus. The frill of Mojoceratops shows marked variation. Some of this variation probably results from intraspecific variation or ontogenetic changes, but because the Dinosaur Park Formation encompasses more than a million years of time, evolution may explain some of these differences. Phylogenetic analysis shows that Mojoceratops forms a clade with Agujaceratops mariscalensis; Chasmosaurus is the most basal member of Chasmosaurinae.


Fossil Record ◽  
2013 ◽  
Vol 16 (2) ◽  
pp. 179-196 ◽  
Author(s):  
J. E. Martin ◽  
P. Vincent

The fourth complete skull of the marine crocodilian <i>Machimosaurus</i> von Meyer, 1837 is hereby described together with an associated complete mandible and disarticulated postcranial elements from the Kimmeridgian of Neuffen, Germany. Although the genus has been described fairly recently on the basis of two nearly complete skulls, their state of preservation did not allow a thorough examination of the entire skull anatomy. Here, we add new information with the description of nicely preserved cranial and mandibular elements of a single individual attributable to <i>Machimosaurus hugii</i> von Meyer, 1837. The diagnosis is updated for the genus and for the species <i>M. hugii</i> and challenges the validity of the second species <i>M. mosae</i> (Liénard, 1876). Moreover, previous assumption that <i>Steneosaurus obtusidens</i> Andrews, 1913 is a junior synonym of <i>Machimosaurus hugii</i> is not supported by our observations. Notably, <i>M. hugii</i> differs from <i>S. obtusidens</i> by a lower tooth count, the morphology of the dentition, the shape of the supratemporal fenestrae and the absence of an antorbital fenestra. Comparative anatomy and a phylogenetic analysis show that <i>Machimosaurus</i> is more closely related to the genus <i>Steneosaurus</i> than to <i>Teleosaurus cadomensis</i> (Lamouroux, 1820). <br><br> doi:<a href="http://dx.doi.org/10.1002/mmng.201300009" target="_blank">10.1002/mmng.201300009</a>


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.


Zootaxa ◽  
2017 ◽  
Vol 4319 (1) ◽  
pp. 177
Author(s):  
MARIA HELENA M. GALILEO ◽  
ANTONIO SANTOS-SILVA

Hudepohlellus Chemsak & Hovore, 2010, a monotypic genus, is considered a junior synonym of Monneellus Hüdepohl, 1985 and M. semilunatus (Chemsak & Hovore, 2010) is a new combination. Kozlovellus bicolor, a new genus and new species of Rhopalophorini is described from Costa Rica. 


Zootaxa ◽  
2018 ◽  
Vol 4540 (1) ◽  
pp. 7
Author(s):  
BEVERLY S. GERDEMAN ◽  
RUFINO C. GARCIA ◽  
ANDREW HERCZAK ◽  
HANS KLOMPEN

The generic classification of millipede associated Heterozerconidae in the Oriental region is revised. The genus Allozercon Vitzthum is re-diagnosed and Asioheterozercon Fain is designated as an subjective junior synonym of Allozercon. Philippinozercon gen. nov., with the type species P. makilingensis sp. nov., is described for all instars. This genus may be endemic for the Philippines, but is quite widespread in that country. All immature instars are described, making this the second species of Heterozerconidae known for all instars. The morphology of the immatures is compared with that of immatures of the temperate species Narceoheterozercon ohioensis and unnamed species from Brazil and Thailand. All immatures were collected from millipede frass and litter, never from millipedes. Adults are associated with millipedes in the family Trigoniulidae (Spirobolida). 


2020 ◽  
pp. 41-48
Author(s):  
FELIX SCHLAGINTWEIT

Orbitolina daviesi Hofker, 1966 (family Orbitolinidae) was validly described and thoroughly illustrated from Thanetian limestones of Pakistan. Although its attribution to the genus Orbitolina d’Orbigny and any phylogenetic relationships with the Cretaceous taxa have been refuted shortly afterwards, the species has not been taxonomically revised since then. Karsella hottingeri Sirel, 1999 was established as new genus and new species from the Thanetian of Turkey, without taking into account J. Hofker’s publication. The original description and genus diagnosis of Karsella has meanwhile been emended to include the occurrence of a radial zone with septula that follow a zig-zag pattern and associated linear arrangement of the foramina, as well as a complex embryo. Orbitolina daviesi clearly displays these features and is here considered a species of the genus Karsella Sirel. Karsella hottingeri is regarded as a subjective junior synonym of O. daviesi Hofker and therefore, the only species of the genus is given as a new combination: Karsella daviesi (Hofker). From a suprageneric viewpoint, the two Paleogene genera Karsella Sirel and Cushmania Silvestri display a complex embryo and might belong to a new subfamily of the Orbitolinidae, phylogenetically different and unrelated to the lower-mid Cretaceous Orbitolininae.


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